显示样式:     当前期刊: Land Degradation & Development    加入关注       排序: 导出
我的关注
我的收藏
您暂时未登录!
登录
  • Net value of farmland ecosystem services in China
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-03
    Shixiong Cao; Junze Zhang; Yujie Liu; Zhongqi Yu; Xu Liu

    Farmland ecosystems are one of the most important landscapes in the world and provide many important ecosystem services for humans. However, most methods of calculating the value of ecosystem services (VES) for these ecosystems have neglected the costs of providing these services or have only considered direct costs. As a result, they have led to the adoption of uneconomical or suboptimal land use and environmental conservation strategies. Because it is increasingly necessary to identify approaches that will produce net benefits both for humans and for the environment that supports us, it is necessary to accurately account for these costs. In this paper, we propose a method for assessing the net value of ecosystem services (NES) for farmland ecosystems, which accounts for both direct and indirect costs, and apply this approach to agriculture in China to provide an improved basis for farmland management. We found that the NES of Chinese farmland decreased from 4.2 × 1012 RMB in 1952 to 3.7 × 1012 RMB in 2014 (1RMB=0.1628USD), in part due to reductions in the area of agricultural land. In addition, the NES in 2014 equaled only 47.4% of the VES, and this percentage would be even lower if more costs could be quantified. Because the direct and indirect costs differ among China's regions, the magnitude of this decrease also varies regionally. To protect China's food security and ecological health, the government will need to adjust farmland management in ways that account for these regional differences to ensure that both humans and our environment benefit.

    更新日期:2018-07-18
  • Three‐dimensional mapping of soil salinity in the southern coastal area of Laizhou Bay, China
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-23
    Wenquan Liu; Xingyong Xu; Fang Lu; Jianrong Cao; Ping Li; Tengfei Fu; Guangquan Chen; Qiao Su

    Soil salinization is an important driver of land degradation and has been a major factor inhibiting agricultural production and development in the southern coastal area of Laizhou Bay. In this study, 3‐D and 2‐D geostatistics were respectively used to evaluate the spatial distribution of soil salinity and groundwater total dissolved solids (TDS) and depth. Results showed that soil electrical conductivity differed greatly within the same soil layer, and the difference in average electrical conductivity of different soil layers was relatively small. The mean value of TDS exceeded 3.0 g L−1 and the mean value of groundwater depth was 13.359 m. The geographic distribution showed that the soil salinity gradually decreased from the north to the south horizontally, and the soil salinity showed a bottom accumulation tendency vertically. Over 90% of the study area has TDS values exceeding 1.0 g L−1, and approximately one‐third of the area had a groundwater depth less than 3.0 m. TDS and groundwater depth had good correlations with soil salinity, with coefficients of determination of 0.544 and 0.572, respectively. Changes in vegetation corresponded to changes in soil salinity. Soil salinity gradually decreased perpendicular to coastal lines in tidal flats without vegetative coverage to inland agricultural areas of wheat and vegetables. Soil salinization in the study area is mainly slight and moderate. Reasonable regional management measures are conducive to improving land economic benefits. The results provide a theoretical basis and reference for the partition, improvement, management of saline soil, and support for land degradation control.

    更新日期:2018-07-18
  • Digital soil erodibility mapping by soilscape trending and kriging
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-23
    Fabio Arnaldo Pomar Avalos; Marx Leandro Naves Silva; Pedro Velloso Gomes Batista; Lucas Machado Pontes; Marcelo Silva de Oliveira

    Spatial representation of soil erodibility (Universal Soil Loss Equation's [USLE] K factor) is critical for soil conservation and erosion modeling. K factor is directly linked to the soil properties, which have a spatially continuous and soilscape related variability. The objective of this study was to test a methodology to map the spatial distribution of soil erodibility in a 1,200 ha sub‐basin making use of available spatial covariates and field data. The analysis was run for the Posses sub‐basin, in southeast Brazil. The topsoil erodibility was calculated at 85 sampled locations. The spatial prediction of soil erodibility was performed using the scorpan approach, in which the trend term for kriging with external drift (KED) was modeled by soilscape covariates selected by multiple linear regression analysis. The results confirmed that relief data could produce feasible results for digital soil erodibility mapping, especially when combined with geostatistical procedures. A comparison with ordinary kriging showed better error statistics and decreased variance of the estimates for the KED model. This could affect significantly the uncertainty of further USLE applications. The best agreement between KED erodibility values and direct measurements of the K factor was observed for the Red–Yellow Argisol (Red–Yellow Ultisol), which is the dominant soil class in the sub‐basin.

    更新日期:2018-07-18
  • Green Roofs: Effects of Plant Species Used on Runoff
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-17
    XiaoXiao Li; JunJun Cao; PeiXian Xu; Ling Fei; Qin Dong; ZhaoLong Wang

    Green roofs are becoming a major nature‐based solution to reduce urban stormwater run‐off worldwide. Run‐off reduction and retention mainly depend on the hydrological characteristics of substrates and the water use strategies of plants. However, little is known about how plant species affect the hydrological performance of green roofs. Two commonly used succulent plants and four turfgrass species were investigated for their impacts on the hydrological performance and run‐off reduction of green roof lysimeters under controlled conditions using a rainfall simulator. The results showed that two succulent plants (Sedum lineare and Callisia repens) did not make significant contributions to canopy interception in any of the four seasons and made only minor contributions to evapotranspiration (ET) water loss in autumn and winter, resulting in minor effects on run‐off reduction by the green roofs. Festuca arundinacea contributed 47.4~116.7% of water loss via transpiration and 36.5% of run‐off reduction under a 25 mm/d rainfall intensity in spring and 48.0% of run‐off reduction under a 10 mm/d rainfall intensity in winter. Poa pratensis, Lolium perenne, and Agrostis stolonifera also significantly reduced run‐off. Run‐off reductions by extensive green roofs were mainly caused by ET rather than by their canopy interceptions. Plant shoot biomass and ET were the primary factors controlling the run‐off reduction by extensive green roofs. Our results strongly suggest that the run‐off reduction capacity of extensive green roofs can be greatly improved by selecting plant species with a higher shoot biomass and ET rate.

    更新日期:2018-07-18
  • Large‐Scale Comparison of Flow‐Variability Dampening by Lakes and Wetlands in the Landscape
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-17
    Andrew Quin; Georgia Destouni

    Considering the potential of wetlands to dampen temporal variability of water flow through the landscape, they are increasingly considered as possible nature‐based solutions to mitigate risks of flooding and drought. In this study, we investigate flow variability by means of a flow dampening factor and use observation data from 1984 to 2013 for 82 Swedish catchments to statistically and comparatively analyse the large‐scale effects on this factor of multiple wetlands and lakes in the landscape. The results show good correlation between large‐scale flow dampening and relative area of lakes and floodplain wetlands within a catchment. An increase in relative area up to around 15 % for lakes and 0.5 % for floodplain wetlands lowers the temporal standard deviation of runoff (R) to around 10‐15 % of that for precipitation (P), compared with a common flow‐variability dampening of around 35% for catchments with lake‐wetland area close to zero. Further increase in these relative areas, or in those of wetland types other than floodplain wetlands, has little or no flow dampening effect. The results indicate that the large‐scale flow dampening effect of lakes and floodplain wetlands is mainly due to their water‐storage capacity and less due to their possible effects on the partitioning of P between R and evapotranspiration. Overall, the results emphasise the importance of accounting for the problem scale and relative water‐storage capacity of wetlands when considering their large‐scale efficiency as possible nature‐based solutions for large‐scale flow‐variability regulation in whole catchments.

    更新日期:2018-07-18
  • Salt stress tolerance mechanisms and potential applications of legumes for sustainable reclamation of salt‐degraded soils
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-16
    Moses Akindele Abiala; Mostafa Abdelrahman; David J. Burritt; Lam‐Son Phan Tran

    Soil salinity is considered one of the most detrimental environmental problems affecting the productivity of many agricultural crops, with negative effects on seed germination, plant vigour and crop yields. To mitigate these negative effects, it is necessary to re‐strategize and identify viable options that are environmentally and economically applicable for sustainable agriculture. This review summarizes and evaluates soil reclamation strategies that have been employed and those that could potentially be used, concentrating on the use of legume crops. Apart from the fact that legumes have many nutritional benefits as foods, they are also an attractive option to re‐fertilize degraded and nitrogen‐deficient soils. Thus, the potential use of grain, grass, shrubby and tree legumes to restore degraded soils requires evaluation. In this review, we discuss and evaluate why legumes should be considered and used for the reclamation of degraded soils, with a particular focus on salt‐degraded soils. Globally relevant case studies that demonstrate how legumes could be used to reclaim salt‐degraded soils are highlighted.

    更新日期:2018-07-18
  • Evaluating the effect of diffuse and point source nutrient transfers on water quality in the Kombolcha River Basin, an industrializing Ethiopian catchment
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-16
    Eskinder Zinabu; Peter Kelderman; Johannes van der Kwast; Kenneth Irvine

    Many catchments in sub‐Sahara Africa are subject to multiple pressures, and addressing only point sources from industry does not address more widespread diffuse pollution from sediment and nutrient loads. This study reports on a preliminary study of nutrient transfers into rivers in two catchments in the industrializing city of Kombolcha, North‐Central Ethiopia. Sampling of rivers and industrial effluents was done over two sampling periods in the wet season of 2013 and 2014. Catchments boundaries and land‐use map were generated from remote sensing and ground data. Higher total nitrogen concentrations were found from sub‐catchments with largest agricultural land use, while highest total phosphorus was associated with sub‐catchments with hilly landscapes and forest lands. Emissions from brewery and meat processing were rich in nutrients (median TN: 21‐44 mg L‐1; TP: 20‐58 mg L‐1), but contributed on average only 10% (range 4 – 80 %) of the TN and 13 % (range 3‐25 %) of the TP loads. Nutrient concentrations in the rivers exceeded environmental quality standards for aquatic life protection, irrigation and livestock water supply. In Ethiopia, more than 85% of farmers operate on less than 2 hectares of land, with concomitant pressure for more intensive farming. Land tenure is exclusively owned by the State, reducing a sense of land stewardship. As the city of Kombolcha moves to agricultural intensification and increased industrialization, attention is needed to fill gaps in monitoring of nutrient pollution in rivers and use information to reconcile development with land use and its degradation.

    更新日期:2018-07-18
  • Evaluation of estuary shoreline shift in response to climate change: A study from the central west coast of India
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-22
    Rajasree B. R.; M. C. Deo

    The prediction of coastal sediment transport and rate of change of shorelines into the future are traditionally done by analysis of historical satellite imageries and field observations or by empirical/numerical modeling. The modeling is traditionally done on the basis of historical data. Instead, here, we suggest the use of future conditions impacted by the climate change for this purpose and a procedure based on regional climate models. Further, considering the difficulty at some places to acquire a large amount of data of various parameters to run a numerical model, we propose the use of simple neural network as an alternative. The location studied belongs to the shoreline adjoining the estuary of River Gangavali, along the central west coast of India. Waves were simulated using a numerical wave model for past and future time periods of 36 years each, and a numerical coastal evolution model was run with this input. It was found that in future, the wave activity at this site would intensify along with certain shift in the direction of wave attack. This will push the net and gross sediment transports up by 131.7% and 114.3%, respectively, and also enhance the shoreline change rate. It was noticed that the future shifts in the wave direction could be as influential as those in the wave height and can cause more accretion of the shoreline. The study emphasizes the importance of considering the projected climate over the past one in planning a regional coastal ecosystem.

    更新日期:2018-07-16
  • Quantitative Interactions Between Total and Specific Enzyme Activities and C and N Contents in Earthworm‐Affected Pear Orchard Soil
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-16
    M. Brzezińska; J. Lipiec; M. Frąc; K. Oszust; P. Szarlip; M. Turski

    The current study describes quantitatively the interactions between (i) activity of extracellular enzymes: β‐glucosidase (BG), protease (Prot), alkaline phosphatase (Alk P), acid phosphatase (Acid P); (ii) intracellular activities: respiration, dehydrogenase activity (DHA); and (iii) C and N contents of soil: Corg – organic carbon, Cmic – microbial biomass, ratio Cmic:Corg, Ntot – total nitrogen, and ratio C:N in earthworm‐affected and surrounding loess soil under a pear orchard. The soil was sampled from the compartments: burrow wall (BW, 0‐3 mm), transition zone (TZ, 3‐7 mm) that form drilosphere, bulk soil (BS, 20 mm from the burrow wall) and cast aggregates (CA). The enzyme activities were presented as total (‘tot’) (per gram of dry soil mass) and specific ‘spec’ (per Cmic). It was shown that soil Cmic, basal respiration, BGtot, Prottot, and Alk Ptot were significantly positively correlated with Corg, Cmic:Corg, Ntot, and C:N (r = 0.627‐0.976). However, the specific BGspec, Protspec, and Acid Pspec were negatively correlated, while specific respiration (qCO2) and Alk Pspec were not correlated with most soil characteristics. The relationships between DHAtot, DHAspec, and all soil characteristics were positive and had the highest correlation coefficients (r = 0.703 ‐ 0.989). Response ratio of the enzyme activity was more strongly affected by enzyme activity location (extra‐ vs. intracellular) and presentation method (total vs. specific), than by earthworm‐affected soil compartments. The results suggest a need to consider the method of enzyme activity presentation (specific vs. total) that implicates understanding ecologically relevant microbial processes in the earthworm‐inhabited orchard soils.

    更新日期:2018-07-16
  • Assessment of Periglacial Response to Increased Runoff. An arctic Hydrosystem Bears Witness
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-16
    Eric Bernard; Jean Michel Friedt; Sophie Schiavone; Florian Tolle; Madeleine Griselin

    In the general context of global warming, the cryosphere appears as an environment which exhibits a strong sensitivity to climate variations. Overall glacier systems are now known to be reliable indicators of climate trends. Although glacier dynamics are subject to international monitoring networks, periglacial environments are much less observed. However, these newly deglaciated areas get wider since glaciers are retreating, and their dynamics become increasingly significant. The observed increase in water fluxes, temperature and precipitation, permafrost melting and reduced cold periods, induce a combined control on modifications of the glacier and periglacial dynamics. Such consequences are also visible on the landscape, hinting at an adaptation of the environment to the climatic forcing.

    更新日期:2018-07-16
  • Effects of precipitation and topography on vegetation recovery at landslide sites after the 2008 Wenchuan earthquake
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-15
    Wentao Yang; Wenwen Qi; Jinxing Zhou

    An important form of land degradation is that induced by landslides. Vegetation recovery at coseismic landslide sites not only plays an important role in reducing soil erosion and increasing land stability but also records the transformation of loose, exposed landslide surfaces into stable hillslopes during the post‐seismic years. However, little is known about the vegetation recovery process or its influencing factors. In this study, we use the Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) dataset, Tropical Rainfall Measuring Mission (TRMM) 3B42 daily precipitation data, and a digital elevation model (DEM) to study the impacts of precipitation and topographic parameters on vegetation recovery after the 2008 Wenchuan earthquake. Our results reveal significant NDVI decreases during the 2008 earthquake and strong recovery in the following years at the coseismic landslide sites. We also found significant negative correlations between precipitation and the derivative of the NDVI trend (NDVIDT) in 2010 and 2011 and significant positive correlations in 2009 and 2013 at the regional scale. These significant negative correlations indicate that precipitation may trigger landslides to remobilize, depressing the recovery of vegetation at coseismic landslide sites during the first few years following a major earthquake. The results further show that site‐specific vegetation recovery is determined by topographic parameters at the local scale. In general, vegetation recovery is weaker at low elevations (< 1300 m) and high elevations (> 3300 m), and it is also weaker on gentler slopes (< 35°) than on steeper slopes (> 35°).

    更新日期:2018-07-16
  • Restoring soil functions by means of cyanobacteria inoculation: Importance of soil conditions and species selection
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-23
    José Raúl Román; Beatriz Roncero‐Ramos; Sonia Chamizo; Emilio Rodríguez‐Caballero; Yolanda Cantón

    In recent years, soil inoculation with cyanobacteria has become one of the most promising biotechnological strategies for restoring soil functionality in degraded drylands because of their critical role in increasing soil fertility and preventing erosion. Nevertheless, in order to fully exploit this biotechnology on a large scale, it must still be shown whether inoculated cyanobacteria are capable of developing in soils with different physicochemical properties, and new candidates adapted to desert conditions must be explored. To evaluate the potential of cyanobacteria for restoring soil functions of degraded dryland soils, in this laboratory study, we analyzed the effect of inoculating three native N‐fixing species (Nostoc commune, Scytonema hyalinum, and Tolypothrix distorta), individually and as a consortium, on soil properties from three different semiarid ecosystems in southeast Spain. The biocrust colonization was monitored by determining chlorophyll a content (the typical surrogate used for biocrust biomass). Other methodologies, such as the analysis of soil spectral response and image classification were also applied for cover estimation of the biocrust. After 3 months, all inoculated soils showed cyanobacteria cover of up to 50%, lower albedo and higher chlorophyll a content. Cyanobacterial inoculation also improved soil functions, as they promoted a significant gain in total organic carbon and total nitrogen in all soils. Among inoculation treatments, Nostoc commune and the mixture of all three species promoted the most cyanobacteria coverage, chlorophyll content, and surface darkening, as well as organic carbon and total nitrogen gains in the soil, highlighting their excellent performance in biocrust development.

    更新日期:2018-07-14
  • Modeling of spatiotemporal variations in runoff contribution areas and analysis of hydrologic connectivity
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-23
    Kendall Grimm; Xuefeng Chu

    Traditional delineation and modeling methods do not consider the spatial arrangement and dynamic threshold control of surface depressions. Instead, full structural hydrologic connectivity, uniform well‐connected drainage networks, and an invariant contributing area are often assumed. In reality, depressions play an important role in quantifying functional connected areas (ACs) and contributing area. This study is aimed to develop a new procedure to analyze functional hydrologic connectivity related to topography at a mesoscale, specifically in depression‐dominated areas by (a) characterizing surface topography, (b) quantifying and locating dynamic hydrologic connectivity, and (c) analyzing hydrologic connectivity and threshold‐controlled dynamics of contributing area using a set of dimensionless indicators and a new normalized connected area function. Thorough analyses for different topographic surfaces provided improved understanding of the intrinsic relationship and interaction between structural and functional hydrologic connectivity patterns. In addition, the new procedure was compared against a traditional delineation method, terrain analysis using digital elevation models (TauDEM), to determine structural and functional connectivity. It was found that spatial arrangement and scale of depressions had a direct effect on hydrologic connectivity. A stepwise trend, unique to depression‐dominated areas, highlighted the effect of threshold behaviors on contributing area and ACs. Conversely, dendritic surfaces showed an expedited surface connectivity due to the assumption of depressionless topography. Thus, precisely locating and quantifying ACs and contributing area via the new analysis procedure improve our understanding of the mechanisms of topography‐controlled overland flow and sediment transport dynamics, and hence, the findings are valuable in making informed decisions about water quantity and quality across varying topographic surfaces.

    更新日期:2018-07-14
  • Optimizing stand structure for trade‐offs between overstory timber production and understory plant diversity: A case‐study of a larch plantation in northwest China
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Bilal Ahmad; Yanhui Wang; Jia Hao; Yanhui Liu; Eve Bohnett; Kebin Zhang

    Trade‐offs are often required for an optimal and sustainable supply of competing services from forests. A study was conducted in northwest China to explore a practical trade‐off approach, for promoting the rehabilitation of service‐degraded plantation, focusing on the two main competing services of timber production and understory plant diversity conservation (expressed by understory vegetation species number [UVSN]). To describe the stand structure parameter variation with age and tree density, the logistic growth model and power function were coupled and fit with field data from 82 plots of larch (Larix principis‐rupprechetii Mayr) plantation within the estimated age range of 12–33 years. The UVSN variation with canopy density and tree density were also quantified. These models and relations developed can serve as a tool for estimating trade‐offs. The results showed that with rising tree density, the single tree timber volume decreased but the stand timber volume increased. The UVSN increased until its maximum, at the canopy density range of 0.6–0.7, and then decreased quickly. A proper tree density corresponding to the optimal canopy density of around 0.7 should be kept for maintaining higher UVSN and adequate timber production. In case of the larch plantation studied, optimal tree densities were found around 2,600, 2,000, 1,600, 1,250, and 1,000 trees/ha for the ages of 15, 20, 25, 30, and 35 years, respectively. Although only two main services were considered, the trade‐off approach developed here can be a reference for future studies to guide the rehabilitation and multifunctional management of service‐degraded plantation.

    更新日期:2018-07-14
  • Land use/land cover change and it's impacts on diurnal temperature range over the agricultural pastoral ecotone of Northern China
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Baocheng Wei; Yaowen Xie; Xu Jia; Xiaoyun Wang; Hongjie He; Xiaoyu Xue

    The agricultural pastoral ecotone of Northern China (APENC), as a fragile ecological zone, has experienced dramatic land use/land cover changes (LULCC) owing to intensive human disturbances. The understanding of the impacts of LULCC on climate, especially the diurnal temperature range (DTR), is not sufficient in this region. The spatio‐temporal processes of LULCC and its impacts on DTR were quantitatively analyzed, using the Terra/Aqua MODIS data (MYD11A2 and MCD12Q1, 2003–2013), on the premise of eliminating or weakening the effects of background climate. Results showed that the areas of croplands, forests, and waterbody increased with the annual rate of 2.84%, 0.95%, and 8.2%, respectively, whereas grasslands and bare land decreased with the annual rate of 0.69% and 7.32%, and built‐up remained quite stable during the period of 2003–2013. The annual changing rate of LULC for 2008–2013 was nearly 2.84 times the value for 2003–2008. In general, LULC contributed to a decline of DTR over the whole APENC both at monthly/seasonal timescale. Croplands, forests, and mutual transformation between croplands and grasslands tended to decrease daytime maximum temperature (Tmax), resulting in a decline of DTR. The grasslands could reduce the DTR by decreasing Tmax and increasing nighttime minimum temperature (Tmin). By contrast, the conversion of grasslands into forests tended to increase Tmax and decrease Tmin, thus a rise of DTR for winter, summer, and autumn had observed. These results can assist land resource development and relevant policies making in APENC.

    更新日期:2018-07-14
  • Structural heterogeneity of vegetation fire ash
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-03-02
    Anna Brook; Lea Wittenberg; Daniella Kopel; Maria Polinova; Dar Roberts; Charles Ichoku; Nurit Shtober‐Zisu

    Any wildfire generates ash, the solid residue derived from burning biomass. Vegetation fire ash consists of charred organic material, charcoal, and inorganic mineral substances. Recent studies identified ash deposits as a dual system: soil and ash strata. The addition of ash to the soil profile alters soil properties and dynamics. A thorough analysis of ash–soil profile reveals a structural appearance of thin laminas. The laminas differ in a variety of physical properties and mineral composition. This research aims at assessing the unique properties of ash–soil profiles by performing an infrared spectroscopic study and statistical analysis. For that purpose, several laboratory experiments were conducted. The paper presents semiquantitative results of spectral analysis calculated by 4 statistical methods. The results indicate a well‐established laminar structure of the ash and evaluate the characteristics of each lamina. The proposed methodology was examined under real‐world conditions; a field experiment of 2‐m2 parcel with in situ O horizon was flamed and burned out. The field samples illustrated the formation of microlaminas, which proved to be similar to the laboratory samples. This detailed approach may promote a better understanding of the complex nature to the ash, the ash–soil interactions and its effect on the edaphic ecosystem.

    更新日期:2018-07-14
  • Assessment of postfire soils degradation dynamics: Stability and molecular composition of humic acids with use of spectroscopy methods
    Land Degrad. Dev. (IF 7.27) Pub Date : 29 Decembe
    Evgeny Abakumov; Ekaterina Maksimova; Anna Tsibart

    The effect of wildfires on the soils of the south taiga and forest‐steppe environments of Central Russia (Histic Spodosols and Eutric Fluvic Arenosols) was investigated in terms of the content and quality of humic acids (HAs) using instrumental spectroscopic methods (solid‐state carbon‐13 nuclear magnetic resonance and electron spin resonance). The bulk elemental composition of HAs was not essentially altered in postfire soils; however, the organic matter of fire‐affected superficial soil layers was characterized by changes in the structural composition and biochemical activity levels. Solid‐state carbon‐13 nuclear magnetic resonance spectroscopy showed that there is an intensive increase in aromatic compounds in HA molecules in soil from both the south taiga and forest‐steppe environments. There is a pronounced and statistically significant decline of aliphatic chain content in response to exposure to fire. The free radicals content and the degree of molecular stabilization assessed with electron spin resonance showed an essential alteration of the HAs, expressed in the increase in the radical's portion, in postfire soils compared with that found in soils not exposed to fire. It was also shown that the accumulation of aromatic compounds indicates only apparent stabilization of HAs due to the loss of periphery alkylic carbon species, which was confirmed by destabilization of the molecules as illustrated by the increase of free radicals.

    更新日期:2018-07-14
  • Composition of microbial community in swine manure biochar‐amended soils and the linkage to the heavy metals accumulation in rice at harvest
    Land Degrad. Dev. (IF 7.27) Pub Date : 19 Decembe
    Xinqiang Liang; Lingling Chen; Ziwen Liu; Yi Jin; Miaomiao He; Ziyi Zhao; Chunlong Liu; Christophe Niyungeko; Yuji Arai

    Manure biochar (MB) is recognized to be a beneficial material for absorbing heavy metals from soil and alleviating soil degradation. However, the effects of the addition of MB on the phospholipid fatty acid concentrations and their linkage to heavy metals accumulation in rice are poorly understood. A microcosm incubation experiment was conducted to study the effects of a swine MB amendment on (a) the composition of the soil microbial community in 2 soils (clay‐loam vs. silt‐loam) and (b) heavy metals accumulation in rice grains and straws. MB amendment increased microbial diversity, and bacteria had greater magnitude of increase than did fungi in 2 soils after 98 days of incubation. The G− rather than G+ bacteria phospholipid fatty acid concentrations were significantly increased with MB amendment rates for both soils. The higher MB addition rate (1.5%) did not get more benefit for aerobic bacteria but significantly led to anaerobic bacteria proliferation as compared with the 0.5% MB treatment. The 1.5% MB addition suppressed grain and straw Pb, Cu, and As, while it increased grain and straw Cd and Zn from two soils. Significant soil type × MB rate interactions were observed in most microbial indicators (except F/B and G+) and grain Pb, grain As, and straw Zn. Linkages of bacteria (mainly as G− and/or An), actinobacteria, fungi, and protozoa (in silt‐loam soil) to the MB rate and heavy metals in rice were identified.

    更新日期:2018-07-14
  • Pyrolysis temperature during biochar production alters its subsequent utilization by microorganisms in an acid arable soil
    Land Degrad. Dev. (IF 7.27) Pub Date : 04 Decembe
    Yu Luo; Jennifer A. J. Dungait; Xiaorong Zhao; Philip C. Brookes; Mark Durenkamp; Guitong Li; Qimei Lin

    Biochar amendment of agricultural soils can have a significant impact on microbial carbon (C) metabolism by providing C substrates and altering soil properties, including amelioration of soil acidity. It remains unclear whether available C of biochar or its pH effects determines the utilization of biochar by microorganisms. Compound‐specific stable 13C isotope analysis of phospholipid fatty acids (13C‐phospholipid fatty acid analysis) was used to explore which microbial group utilized biochar distinguished with pHs and C availability. C4 Miscanthus biochar (δ13C = −12.2‰) was prepared at 2 pyrolysis temperatures (350 °C and 700 °C) and applied (50 mg C g−1 soil) to a very acid soil (pH 3.7, δ13C = −27.7‰), which was sampled from the long term Hoosfield Acid Strip experiment at Rothamsted Research, and incubated for 14 months. Biochar700 increased soil pH to 5.1 and biochar350 increased soil pH to 4.3. All microbial groups (Gram‐positive bacteria, Gram‐negative bacteria, actinobacteria, and fungi) were more abundant in the biochar‐treated soils. The 13C values of biomarker phospholipid fatty acid analysis suggested that all groups of microorganisms, and especially Gram‐positive bacteria, were using the C from the biochar350, but not the biochar700, as a substrate. We conclude that its utilization of biochar by microorganisms after 14 months was largely determined by the pyrolysis temperature controlling the availability of biochar C, instead of the pH effects, in a very acidic soil.

    更新日期:2018-07-14
  • Impact of forest fires generated black carbon deposition fluxes in Great Hinggan Mountains (China)
    Land Degrad. Dev. (IF 7.27) Pub Date : 29 Novembe
    Chuanyu Gao; Jiabao He; Jinxin Cong; Shaoqing Zhang; Guoping Wang

    Black carbon is produced by incomplete combustion of fossil fuels and biomass. The production of black carbon over the last several centuries has been primarily influenced by human activities. Human exploitation of forest resources, together with increases in regional fire frequency and intensity, can increase regional black carbon emissions and can led more black carbon deposited into natural ecosystem. Here, based on 210Pb age‐depth model, we investigated black carbon deposition over several key periods in the last 150 years in 5 peatlands of the Great Hinggan Mountains (Northeast China), an area that has been exploited by humans without forest protection policies. The results showed that average black carbon deposition fluxes from different peatlands in the Great Hinggan Mountains were 1.1 to 4.8 mg·year−1·cm−2, which were similar to other peatland distribution regions and higher than other ecosystems. Frequent and intense fire events during the exploitation period led to regional peak black carbon deposition before the 1980s. After the 1980s, fire events were controlled, and the government implemented forest protection policies that decreased the trend in regional fire frequency in the Great Hinggan Mountains and markedly decreased black carbon deposition. Fire events controlled by regional human activities are therefore the major factor that influence regional black carbon deposition fluxes, and frequent forest fires could increase black carbon deposition fluxes in surrounding ecosystem.

    更新日期:2018-07-14
  • Simultaneous measurement of bacterial abundance and composition in response to biochar in soybean field soil using 16S rRNA gene sequencing
    Land Degrad. Dev. (IF 7.27) Pub Date : 26 Novembe
    Xiaorui Liu; Jia Li; Lu Yu; Hong Pan; Haiyang Liu; Yimeng Liu; Hongjie Di; Yong Li; Jianming Xu

    Biochar is an important soil conditioner. However, we have limited understanding of biochar effects on the microbial community traits of the rhizosphere and bulk soil in the field. The aim of this study was to examine the impacts of biochar amendment on microbial abundance and community in the rhizosphere and bulk soils in soybean‐growing fields. We applied 16S ribosomal RNA (rRNA) gene sequencing with an internal standard gene to quantitatively investigate biochar‐mediated changes in microbial composition and abundance in rhizosphere and bulk soils. The results indicated that the absolute abundance of bacterial taxa with internal standard can be more informative in describing soil microbial population distribution. A linear discriminant analysis effect size differential analysis showed that the biochar amendment significantly altered the soil microbial abundance and community composition. The bacteria in the rhizosphere soil showed more clear responses to biochar addition than the bacteria in the bulk soil. These results highlight the enhanced effect by biochar on bacterial population distribution in the rhizosphere. 16S rRNA gene sequencing with internal standard gene represents an effective method that can substantially improve 16S‐seq based microbiome studies by determining the 16S rRNA gene abundance and bacterial community composition simultaneously.

    更新日期:2018-07-14
  • Impact of biochar properties on soil conditions and agricultural sustainability: A review
    Land Degrad. Dev. (IF 7.27) Pub Date : 29 Novembe
    Mohammad I. Al‐Wabel; Qaiser Hussain; Adel R.A. Usman; Mahtab Ahmad; Adel Abduljabbar; Abdulazeem S. Sallam; Yong Sik Ok

    This review summarizes the influences of pyrolysis conditions and feedstock types on biochar properties and how biochar properties in turn affect soil properties. Mechanistic evidence of biochar's potential for enhancing crop productivity, carbon sequestration, and nutrient use efficiency are also discussed. The review identifies the knowledge gaps, limitations, and future research directions for large‐scale use of biochar. Both pyrolytic parameters and feedstock types are considered to be the main factors controlling biochar properties such as nutrient content, recalcitrance, and pH. Biochar produced at low temperatures may improve nutrient availability and crop yield in acidic and alkaline soils, whereas high‐temperature biochar may enhance long‐term soil carbon sequestration. Biochar can also improve the efficiency of inorganic and organic fertilizers by enhancing microbial functions and reducing nutrient loss, thereby making nutrients more available to plants. Integration of biochar and chemical or organic fertilizers generally provides for better nutrient management and crop yield in most types of soils. Although biochar can improve degraded soils, it is not a panacea; as such, soil‐ and crop‐specific biochar are needed in order to ensure optimum crop yield and agricultural sustainability.

    更新日期:2018-07-14
  • Eastern China coastal mudflats: salt‐soil amendment with sewage sludge
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-13
    Yanchao Bai; Wengang Zuo; Lijuan Mei; Boping Tang; Chuanhui Gu; Xukui Wang; Hongbo Shao; Yongxiang Guan

    The mudflats developed along the east coast of China can be important alternative land sources for agricultural purpose after amending with organic fertilizers in large amounts. Abundant in quality organic matter and other plant nutrients, municipal sewage sludge has great potential to be used in mudflat amendment. However, the conflict between agricultural benefits from soil fertility elevation and environmental risks from hazard substances existing in sewage sludge is the critical issue to be resolved before large‐scale application of sewage suldge into salt‐affected degradaed mudflats. In compliance with the national standard for land application in China, raw sewage sludge and its compost can be used to amend mudflat salt‐soil by one‐time or multiple‐time application. One‐time input of sewage sludge followed by planting and tilling green manure has proved to be an optimal way for rapidly improving salt‐affected soil degradation with sustaining fertility benefits and minimal environmental risks. In salt‐soil amended with sludge, soil organic matter content was significantly elevated, and soil physicochemical properties were subsequently improved due to the increase of soil porosity, available nitrogen and phosphorus and the decrease in bulk density, salinity and pH in salt‐soil. Application of sewage sludge to mudflat soils increases soil total and bio‐available heavy metals derived from sludge application, thus increases risk of metal uptake by plants grown in mudflat salt‐soil. Environmental risks still represent a major issue in mudflat salt‐soil amendment by sewage sludge. Future holistic environmental risk assessment is warranted before using sewage sludge to amend mudflat salt‐affected degradated soil in China.

    更新日期:2018-07-14
  • An assessment of the variation of soil properties with landscape attributes in the highlands of Cameroon
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-23
    Bertin Takoutsing; John C. Weber; Jose Antonio Rodríguez Martín; Keith Shepherd; Ermias Aynekulu; Andrew Sila

    Soil properties are useful for assessing the potential of landscapes to provide terrestrial ecosystem services, but they are affected by anthropogenic activities and environmental factors including landscape attributes. This study assessed how soil properties are influenced by landscape attributes and their interactions in the highlands of Cameroon using the Land Degradation Surveillance Framework as a data collection tool. Soil properties (soil organic carbon [SOC], clay content, exchangeable bases [ExBas], electric conductivity [EC], boron [B], manganese [Mn], phosphorus [P], pH) were quantified within classes of landscape attributes. Soil samples were collected on 160 (1,000 m2) plots randomly located in a sentinel site of 100 km2 and were analyzed using a combination of conventional laboratory methods and mid‐infrared spectroscopy. Soil properties were highly affected by soil depths, land use types, slope gradients, and topographic positions, but less by their interactions. Significant interactions existed between land use types and topographic positions for SOC, EC, ExBas, and pH, and between slope gradients and topographic positions for pH, whereas Mn was influenced by the interaction between land use types and slope gradients. Most soil properties were higher in low altitude plots and those with higher vegetation cover but decreased in the upslope direction. The pH and clay contents were less affected by slope gradient confirming the inherent nature of the properties. These results are useful for site‐specific implementation of ecological intensification in areas with complex topography such as the highlands of Cameroon, offering a reference for future ecological policies and landscape restoration.

    更新日期:2018-07-12
  • What deep‐soil profiles can teach us on deep‐time pH dynamics after land use change?
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-22
    Boris Brasseur; Fabien Spicher; Jonathan Lenoir; Emilie Gallet‐Moron; Jérôme Buridant; Hélène Horen

    Soil profiles keep records of the legacies of historical land uses on soil physicochemical properties with deep‐soil (3‐m depth) profiles providing information on centuries‐old dynamics. By combining geohistorical archives on past land uses and management practices together with soil pH data from 19 plots scattered across five study areas in North France, we analyzed the effect of two contrasting historical land‐use change trajectories (afforestation of former arable land vs. cultivation after deforestation) on the acidification and alkalinization dynamics along 3‐m‐depth loessic Luvisols profiles. An analysis of covariance and a generalized additive model were used to test the interaction effect between depth and the two studied chronosequences levels on soil pH. Results show two contrasting alkalinization dynamics for formerly acidic forest soils converted to arable land depending on past management practices. One century of liming practices based on hydrated lime is enough for a complete deprotonation, whereas alkalinization dynamic was much slower (two to four centuries are necessary to neutralize the relictual acidity below 2 m) under liming based on chalk‐blocks supply. Per contra, afforestation of former arable land cultivated and limed during at least 2–4 centuries keep an alkaline ‘memory’ effect over more than a millennium. The acidification process is progressive through time from the surface to deeper soil horizons. This suggests that soil pH profiles can be used to estimate time since afforestation of former arable land. Linking deep‐soil pH profiles with chronosequences is a powerful tool to understand the potential impact of future land‐use change trajectories on soil physicochemical properties.

    更新日期:2018-07-12
  • Paddy periphyton: Potential roles for salt and nutrient management in degraded mudflats from coastal reclamation
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Haiying Lu; Weicong Qi; Jia Liu; Yanchao Bai; Boping Tang; Hongbo Shao

    Periphyton exists ubiquitously in paddy ecosystems of coastal mudflat area, playing significant roles in salt and nutrient cycling between the water and soil interface. However, the definition, composition, influenced factors, and potential function of paddy periphyton are still unclear. We attempt to define paddy periphyton as an integrated and independent microcosm, which is dominated by phototrophic communities, containing both biotic components, such as algal, fungal, bacterial, protozoan, and metazoan, and abiotic components, such as soil, extracellular polymeric substance, and detritus. They interact with each other such as predation and competition, co‐inhabiting in a common microhabitat. The development of paddy periphyton mainly includes three processes: growth stage, mature stage, and fading stage. Paddy periphyton has a significant influence on the salt migration in paddy ecosystem that was reclaimed from coastal mudflat by improving the soil structure, assimilating and adsorbing the salt like sodium chloride, and inhibiting the salt accumulation near the soil surface. As for nutrient management, the roles of paddy periphyton can be summarized as a slow‐released bio‐fertilizer, a nutrient‐removal agent, a nutrient mediator, and a nutrient indicator in mudflat‐reclaimed paddy ecosystem. All these imply that paddy periphyton may be a new and promising biotechnological tool for better salt and nutrient management in paddy ecosystems that degraded from mudflat land, which has a vast potential in the amelioration and fertility improvement of salt‐affected soils, as well as control of nonpoint agricultural pollution in coastal areas.

    更新日期:2018-07-12
  • Measuring the impacts of anthropogenic activities on Inner Mongolian temperate grassland
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Hongrui Ren; Guangsheng Zhou

    Measuring the impacts of anthropogenic activities on grassland ecosystems is of great significance to establish effective grassland management policies. Due to the uncertainty and complexity of the anthropogenic activities, the impacts are difficult to quantify, especially at large spatial and long temporal scales. We used the Zhou Guangsheng model to simulate climate‐driven potential net primary productivity (NPPP) and MOD17A3 NPP data to acquire actual NPP (NPPA) influenced by both anthropogenic activities and climate change over the temperate grassland of Inner Mongolian from 2000 to 2014. We then simulated human‐induced NPP (NPPH), calculated as the difference between actual and potential NPP (NPPH = NPPA − NPPP), to determine anthropogenic effects on the temperate grassland. By comparing the NPPH and its time‐series linear slope from 2000 to 2014, we further proposed six types of anthropogenic impacts. Along the temperate grassland climate gradient, vegetation changed from meadow steppe in the east to typical steppe in the middle and desert steppe in the west, and NPPA and NPPP decreased. NPPH had no obvious spatial pattern. We observed positive effect (NPPH > 0) on only 4.2% of total grassland area. The area where the types of “positive effect (NPPH > 0) decrease – negative effect (NPPH < 0) increase” and “negative effect (NPPH < 0) increase” were observed in time‐series trends accounted for 68.8% of total grassland area. The grazing withdrawal and ecological compensation programs implemented around 2004 did not lead to a decline in the number of livestock and NPPH. Governments need to improve livestock number controls and strengthen grazing regulations.

    更新日期:2018-07-12
  • Plant community ecological strategy assembly response to yak grazing in an alpine meadow on the eastern Tibetan Plateau
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Jun Wang; Chunyan Zhang; Hao Yang; Chengxiang Mou; Li Mo; Peng Luo

    Predicting the impact of grazing on vegetation structure, and thus on ecosystem services, is one of the main technical bottlenecks in alpine grassland conservation and management. However, past researches based on the fixed, discrete, and qualitative indicators limited our understanding for the effect of grazing on plant community assembly. Research based on the quantitative competitor, stress tolerator, and ruderal (CSR) theory increases the possibilities for analyzing this ecological process. To test the hypothesis that the dominant plant strategy in alpine meadow plant community will shift from S‐selection to R‐selection with increased grazing intensity, the plant community CSR strategy assemblies among the cold‐seasonal grazing meadows along a gradient of grazing intensity were studied on the eastern Tibetan Plateau. The dominant strategy concentrated in the S‐selected corner under the low grazing intensity, which provided a direct evidence to the environmental filters in the alpine area, and suggested that species of strong S‐selection should dominate the undisturbed alpine grassland plant community. The C‐selection of dominant strategies increased (R2 = 0.431, p = 0.004), and the extent of S‐selection decreased with greater grazing intensity; however, the R‐selection of them only slightly increased under intermediate grazing intensity and finally decreased under high grazing intensity, reflecting a selective grazing disturbance combined with localized enrichment of soil that can provide microsites for the establishment of competitors. The strong C‐selected species may dominate the plant community on the eastern Tibetan Plateau in place of S‐selected and R‐selected species, if the grazing intensity is continually high.

    更新日期:2018-07-12
  • Spatial prediction of soil erosion susceptibility using a fuzzy analytical network process: Application of the fuzzy decision making trial and evaluation laboratory approach
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Farzaneh Sajedi‐Hosseini; Bahram Choubin; Karim Solaimani; Artemi Cerdà; Ataollah Kavian

    Soil erosion is a worldwide threat that results in soil degradation, agriculture abandonment, and crop yield reduction. There is a need to find methods to survey soil erosion rates in order to improve and develop sustainable land planning. The present study utilizes new approaches based on the fuzzy set both in designing the problem (through the fuzzy decision making trial and evaluation laboratory) and in prioritizing the effective factors to mitigate soil erosion (using a fuzzy analytical network process, FANP). This study is first to apply these methods to soil erosion. A set of geo‐environmental factors influencing soil erosion was characterized to evaluate the potential risk of soil erosion in the Nor‐Rood watershed in Iran. The layers of information were developed using expert knowledge, and a network structure was designed by the fuzzy decision making trial and evaluation laboratory method. Then, the weights of layers were calculated by the FANP method by considering the internal and external interaction between factors. The erosion susceptibility map was produced by combining layers based on their weights in a geographic information system platform and was validated using erosion occurrences recorded in field surveys. Results revealed that FANP model accuracy is high (83.4% accuracy) for the study area. We found that vegetation, drainage density, land use, and soil erodibility are the key parameters to explain the soil erosion rates. The soil erosion risk map developed by the FANP method provides useful information for sustainable planning and risk mitigation and can be used in a data‐poor environment.

    更新日期:2018-07-12
  • Construction of coastline shelterbelts and assessment of their environmental effects in Yuyao, China
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Qihua Shan; Jianfeng Zhang; Shiyong Sun; Guangcai Chen; Handan Zhang; Liming Shen

    There is 18,000 km of coastline in China. It is extremely important to construct coastal shelterbelts as they have a unique and irreplaceable role in the prevention and mitigation of natural disasters and in maintaining the ecological balance of coastal regions. A coastal shelterbelt was constructed near Yuyao City, Zhejiang Province, and three plots (wasteland, farmland, and forest) were studied to investigate the effects of environmental factors on the diversity of herbaceous plants. The environmental benefits were analyzed by field surveys and soil sampling. A total of 31 species from 30 genera and 14 families of halophyte and salt‐tolerant grasses were found in the survey area. The wasteland included 21 species from 20 genera and 9 families, whereas the shelterbelt forest had 19 species from 19 genera and 8 families, with Poaceae and Asteraceae dominating. Moreover, the Sørensen coefficient for the shelterbelt forest and wasteland was 65 and that for the shelterbelt forest and farmland was 55.56. Additionally, the salinity decreased from 0.52% to 0.02% after 2 years, similar to the value for farmland that has been cultivated for decades. The organic matter content increased from 5.1 to 9.5 g/kg, and the total nitrogen content increased from 0.34 to 0.47 g/kg. We concluded that coastline shelterbelts could be successfully established on the muddy coast. With coastline shelterbelts growing, the structure and diversity of herbaceous plants were affected, and the soil conditions were improved. Therefore, the construction of shelterbelt forest would improve the coastal landscape and enhance soil properties, accelerating the succession of herbaceous plants.

    更新日期:2018-07-12
  • Effects of land‐use changes on runoff and sediment yield: Implications for soil conservation and forest management in Xishuangbanna, Southwest China
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Xiai Zhu; Wenjie Liu; Xiao Jin Jiang; Pingyuan Wang; Weixia Li

    Effects of vegetation traits and soil physical properties on runoff and sediment yield were investigated under different land uses in Xishuangbanna, Southwest China. The cutting‐ring method was applied, and field plot experiments were conducted to determine soil physical properties and monitor runoff and sediment yield in response to land‐use change by comparing tropical rainforest (TR), rubber monoculture (Rm), and four rubber‐based agroforestry systems. Results showed that conversion of tropical forest to rubber resulted in lower leaf area index (LAI), canopy cover, less litter, and an unfavorable soil environment (i.e., high bulk density [BD], low porosity, etc.). The runoff from the Rm was 33.2‐ and 2.6‐ times higher than the TR and the rubber‐based agroforestry systems, respectively. In general, sediment yield from the TR, Rm, and agroforestry systems was 0.041, 11.54, and 2.73 t ha−1, respectively. These trends suggested that the forest conversion caused negative hydrological consequences (i.e., excessive runoff and sediment yield). Compared with the Rm, rubber‐based agroforestry systems could more effectively reduce runoff volume and sediment yield. Overall, the sediment yield were significantly negatively correlated with LAI, canopy cover, stand litter, and saturated water capacity, while positively correlated with BD and runoff. The effects of precipitation on the sediment yield of agroforestry systems in this region became less important due to their partly improved soil conditions and vegetation traits. Solely from the point of erosion control, we recommend that local governments and farmers should consider intercropping Flemingia macrophylla and Theobroma cacao tree species within Rm plantations.

    更新日期:2018-07-12
  • Statistical check of USLE‐M and USLE‐MM to predict bare plot soil loss in two Italian environments
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Vincenzo Bagarello; Vito Ferro; Giuseppe Giordano; Francesco Mannocchi; Francesca Todisco; Lorenzo Vergni

    The USLE‐M and the USLE‐MM estimate event plot soil loss. In both models, the erosivity term is given by the runoff coefficient, QR, times the single‐storm erosion index, EI30. In the USLE‐MM, QREI30 is raised to an exponent b1 > 1 whereas b1 = 1 is assumed in the USLE‐M. Simple linear regression analysis can be applied to parameterize both models, but logarithmically transformed data have to be used for USLE‐MM. Parameterizing the USLE‐MM with nonlinear regression of untransformed data could be a more appropriate procedure. A statistical check of the two suggested models (USLE‐M and USLE‐MM), considering two alternative parameterization procedures for the USLE‐MM, was carried out for the Masse and Sparacia experimental stations, in Italy. The analysis showed that the USLE‐MM with the linear regression parameterization procedure was the only correctly specified model, that is, with normally distributed and homoscedastic residuals. With this model, the normalized soil loss, Ae,N, prediction error did not exceed a factor of 5.7 for Ae,N > 17.3 Mg ha−1 at Masse and of 3.5 for Ae,N > 27.5 Mg ha−1 at Sparacia. Stable values of b1 require inclusion of high Ae,N values in the calibration dataset. Using a common exponent b1 for the two stations increases the practical interest for the model and did not imply a substantial worsening of the model performances, especially for the highest soil loss values. Development of a USLE‐MM‐type model having a wide applicability appears possible, and data from other experimental sites could make this conclusion more robust.

    更新日期:2018-07-12
  • Recovery of biogeochemical processes in restored tropical dry forest on a coal mine spoil in La Guajira, Colombia
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Jeiner Castellanos Barliza; Juan Diego León Peláez; Julio Campo

    Open‐cast coal mining eliminates vegetation, alters physical and chemical characteristics of soils, and therefore limits the establishment of native vegetation by lack of sufficient moisture, increase bulk density, and low organic matter content. Restoration of extremely degraded areas through plantation of fast growing species is expected to accelerate the recovers of soil organic matter and nutrient cycles. The purposes of this study were to compare intrasystem cycling of C, N, P, and base cations in native and restored forests at an open‐cast coal mine in a dry region of Colombia. Leaf‐fall, standing leaf litter, and their N, P, Ca, Mg, and K contents were measured for 1 year in native forests and restored forests of various ages (7, 10, and 21 years). The exploitation of coal in La Guajira degraded soil fertility, and although tree planting was sufficient to achieve the partial recovery of soil chemistry and N cycling relative to reference conditions (i.e., native forest), a P deficiency in forest function remained unresolved even 21 years after restoration. The restoration of biogeochemical processes, particularly of critical processes of the P cycle, requires additional human interventions (such as the application of nutrient‐rich litterfall from native forests of the region) that favor nutrient dynamics and lead to the recovery of a self‐sustaining ecosystem. Thus, multiple efforts are needed for the restoration of these dryland forests to recover ecosystem services (such as soil fertility) that improve C sequestration and help mitigate climate change.

    更新日期:2018-07-12
  • Establishing a land degradation neutrality national baseline through trend analysis of GIMMS NDVI Time‐series
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Helene Gichenje; Sérgio Godinho

    The land degradation‐neutrality (LDN) national baseline for Kenya in 2015 was established in terms of the three LDN indicators (land cover, land productivity, and carbon stocks), and using trends in GIMMS NDVI and land cover datasets over the 24‐year period from 1992 to 2015. Human‐induced land degradation was separated from degradation driven by climate factors using soil moisture data and the residual trend method. On the basis of Kendall's tau of the NDVI residuals computed using annual mean data of the NDVI and soil moisture relationship, the country has experienced persistent negative trends (browning) over 21.6% of the country, and persistent positive trends (greening) in 8.9% of the country. The land cover change map for the period 1992–2015 showed that in 5.6% of the area there was a change from one land cover class to another. Pronounced changes in terms of land area were the increase in grasslands by 12,171 km2, the decrease of bare land by 9,877 km2, and the decrease in forests by 7,182 km2. Browning and greening trends account for 13% and 12%, respectively, of the land cover change areas. By establishing the LDN national baseline, the LDN concept is now operational. As a first step, targeted field level assessments, alongside the collection of data for the computation of soil organic carbon stocks, should be undertaken in selected browning, greening, and land cover change sites. These field studies will provide decision makers with key information on how to plan for the implementation and monitoring of LDN interventions.

    更新日期:2018-07-12
  • Management of pruning residues for soil protection in olive orchards
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Manuel Moreno‐García; Miguel Angel Repullo‐Ruibérriz de Torres; Rosa María Carbonell‐Bojollo; Rafaela Ordóñez‐Fernández

    Erosion is one of the main environmental problems affecting soil in olive orchards. The present research aims to study the protection effect against soil erosion of three different managements of pruning residues in olive orchard. The investigation was carried out in an olive orchard with a total production of 0.39 kg m−2 of dry weight of pruning residues every 2 years. These pruning were chopped and scattered in 2 m‐wide strips through three different managements. Management A, with densities of 1.56 kg m−2 distributed in all the inter‐rows of olive orchard. Management B, with densities of 3.12 kg m−2 distributed on half of the inter‐rows of olive orchard. And management C, with densities of 3.12 kg m−2 distributed on half of the inter‐rows of olive orchard, alternating this application every 2 years with another half of the inter‐rows. The influence of the residues on soil protection has been measured through the evolution of three parameters of the residues over 4 years: residues mass degradation, soil cover percentage, and spatial distribution. The results of the study have shown that the management C is the one that best protects the soil from erosion in olive orchard. This management maintains a protecting cover over inter‐rows of olive orchard above 40%, maintaining homogeneity of the cover twice as much as the management in which pruning residues are left in all inter‐rows.

    更新日期:2018-07-12
  • Influence of climate and land use changes on recent trends of soil erosion rates within the Russian Plain
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Valentin Golosov; Oleg Yermolaev; Leonid Litvin; Nelli Chizhikova; Zoya Kiryukhina; Gusel Safina

    The Russian Plain (within the Russian Federation) occupies an area of approximately 3.5 × 106 km2. Water erosion is the main land degradation factor within the Russian Plain. Previous quantitative assessments of erosion rates for the entire area of the Russian Plain were undertaken in the 1980s. The application of erosion models and analysis of different factor dynamics allow for the evaluation of the mean annual total soil losses and erosion rates for the post‐Union of Soviet Socialist Republics period, as well as the determination of the trends of erosion rates and soil losses for different landscape zones, for 1980 and 2012. The significant reductions of cultivated land area in all of the landscape zones after 1991 are the main reason behind the 46% reduction in the total annual soil losses in 2012 compared with 1980. The most significant decrease in the soil erosion rate for cultivated lands (from 7.3 Mg ha−1 yr−1 in 1980 to 4.1 Mg ha−1 yr−1 in 2012) was identified in the forest zone of the Russian Plain. Soil erosion rates slightly decreased in the forest‐steppe zone and increased in the steppe zone (from 3.9 to 4.6 Mg ha−1 yr−1). We attribute the decreasing erosion rates in the forest and forest‐steppe zones to the reduction of surface runoff during snowmelt. The increased use of perennial grasses in crop rotations promoted the reduction of erosion rates in the forest zone. The increasing erosion rates in the steppe zone were attributed to the increasing frequency of heavy rainstorms.

    更新日期:2018-07-12
  • Modelling and mapping erosion in smallholder agro‐ecosystems, Tanzania
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Juma Wickama; Aad Kessler; Geert Sterk

    The West Usambara Highlands in north‐eastern Tanzania have many smallholder agro‐ecosystems with unknown composition, management, and vulnerability to erosion. Their specific locations and spatial extent are difficult to trace by satellite images or remote sensing imagery alone. To address these limitations, we combined ground soil surveys, geographic information system, and erosion modelling to (a) locate and map smallholder agro‐ecosystems, (b) determine their biophysical characteristics, and (c) model their soil losses. Land resource information was collected from 301 random 0.1‐ha plots sampled from a total area of 200 km2. Annual soil losses were estimated using the universal soil loss equation. The study located six dominant agro‐ecosystems with the following spatial extent: maize‐bean (24.9%), maize‐bean‐agroforestry (31.2%), maize‐bean‐agroforestry‐high value trees (18.9%), tree farms (7.0%), forests (15.6%), and grazing lands (2.3%). Agroforestry and other tree‐based agro‐ecosystems dominate the area due to historical land use change and later institutional interventions. This study finds combined use of soil surveys, geographic information system, and modelling to be reliable in locating, mapping, and assessing soil losses in smallholder agro‐ecosystems. The agro‐ecosystems differ significantly (p < 0.05) in slope, vegetation cover, soil conditions, and soil losses. Soil loss in the maize‐bean agro‐ecosystem (28.3 t ha−1 yr−1) was 18 times higher compared with natural forests (1.57 t ha−1 yr−1) due to lower soil cover and inefficient conservation and cultivation practices. Our results show that adoption of soil conservation measures and improved vegetation cover technologies across the agro‐ecosystems reduces soil losses by 37% and increases organic carbon levels by 16%.

    更新日期:2018-07-12
  • Identification of the most limiting factor for rice yield using soil data collected before planting and during the reproductive stage
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-06
    Ming‐Ming Wang; Pichu Rengasamy; Zhi‐Chun Wang; Fu Yang; Hong‐Yuan Ma; Li‐Hua Huang; Miao Liu; Hao‐Yu Yang; Jing‐Peng Li; Feng‐Hua An; Yang‐Yang Li; Xiao‐Long Liu; Zheng‐Wei Liang

    Soil parameters, measured before crop planting, are typically used to quantify the relationship between soil properties and crop yield and to identify factors limiting crop yield. However, soil properties during sensitive stages of crop growth may have a greater effect on crop yield than the initial values. We determined if inclusion of soil properties, measured during the reproductive stage, could improve the accuracy of crop yield prediction. Classification and regression trees were used to determine the explanatory power of different soil and rice variables for predicting rice yield in alkaline salt‐affected paddy fields in northeast China. The traditional method explained 77.5% of the rice yield variation and identified soil CO32− in the 0‐ to 10‐cm soil layer, with single explanatory power of 53.4%, as the most important predictor. The whole explanatory power of the methods including soil variables during the reproductive stage and yield components, with/without soil variables before planting, increased to 81.3%. The residual sodium carbonate, measured in the 0‐ to 10‐cm soil layer during the reproductive stage, was identified as the most limiting factor due to its single maximum explanatory power of 60.5%. We conclude that inclusion of soil properties, measured during the reproductive stage, has potential for improving the rice yield prediction accuracy by enhancing the explanatory power in identification of the most limiting factor. These results encourage further investigation of the role of soil properties during sensitive stages of crop growth in crop yield prediction under different soil and climatic conditions.

    更新日期:2018-07-12
  • RECENT EVOLUTION OF AN ICE‐CORED MORAINE AT THE GENTIANES PASS, VALAIS ALPS, SWITZERLAND
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-11
    L. Ravanel; P.‐A. Duvillard; M. Jaboyedoff; C. Lambiel

    Lateral moraines located in permafrost environments are susceptible to preserve large amount of both glacier and periglacial ice. To understand how ice‐cored moraines located in high alpine environments evolve in a context of both glacier retreat and permafrost degradation, we performed, 11 terrestrial laser‐scanning measurement campaigns between 2007 and 2014 on a highly anthropogenic overprinted moraine prone to instability. Resulting comparison of the subsequent 3D models allowed to qualitatively and quantitatively analyze the morphological evolution of the moraine. The comparisons indicate a very high geomorphic activity of the moraine including large areas affected by downslope movements of blocks and 10 landslides with a volume between 24 ± 1 and 1138 ± 47 m3. Data also indicated a very strong ice melt with a loss of ice thickness locally reaching 17.7 m at the foot of the moraine. These results, compared with resistivity and thermal measurements of the ground, suggest the combined role of ice loss at the foot of the moraine and the permafrost activity/warming in triggering these processes.

    更新日期:2018-07-12
  • ANALYSIS OF SALINE GROUNDWATER INFILTRATION INTO TWO LOAM SOILS
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-11
    Junna Sun; Fuhong He; Zhenhua Zhang; Yinghua Pan; Yang Runya; Wenxue Li; Peng Li; Mengzhu Zheng; Hongbo Shao

    Irrigation with saline groundwater may cause salt accumulation in the soil and even land degradation in coastal areas. The aim of this study was to reveal how the changes in groundwater salinity affect the infiltration characteristics under controlled conditions. One‐dimensional vertical infiltration experiments were conducted in uniform columns of silty clay loam and sandy loam under different salinity levels of irrigation groundwater (0, 1, 2, 3, 6, 9, and 12 g L–1 NaCl). The results showed that as groundwater salinity increased, the infiltration capacity of the silty clay loam increased under low salinity levels but decreased under higher salinity levels, with a turning point at the salinity of 6 g L–1 NaCl. However, there were no significant differences in the infiltration capacity of the sandy loam under salinity levels of 1 – 9 g L–1 NaCl, while a significant increase was found under 12 g L–1 NaCl. The infiltration capacity of the sandy loam was consistently higher compared with the silty clay loam under different salinity levels. Under short‐term irrigation with a conventional amount of 750 – 900 m3 ha‐1, extracting groundwater with the salinity of <6 g L–1 NaCl obtained higher desalination efficiency in the silty clay loam and resulted in less salt accumulation in the surface soil (0–20 cm). Under the same amount of irrigation with groundwater containing 1–12 g L–1 NaCl, the increase of soil salt content was relatively small in the sandy loam and might not significantly affect on crop growth.

    更新日期:2018-07-12
  • Isotopic Biogeochemical Indicators of Evapotranspiration and Nitrogen Flows in a Check‐Dam Catchment in the Loess Plateau, China
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-11
    Shibo Chen; Yong Huang; Linhua Wang; Weiliang Chen; Yafeng Wang; Yang Gao

    The increasingly fragile ecological environment and associative nitrogen (N) biogeochemical cycle have become critical environmental and ecological issues in China's Loess Plateau. However, N flow and N source for typical catchments remains poorly understood in the Loess Plateau. In this study, we measured concentrations and isotopic signatures of N, hydrogen (H), and oxygen (O) in both rainfall and river water. Results showed that baseflow variation in total nitrogen (TN) concentrations ranged from 0.16 to 32.70 mg L‐1. The monthly TN deposition flux and monthly TN wet deposition concentration to river water were shown significant variations between rainy and dry seasons. The range of variation in δ2H values for rainfall and baseflow were from ‐90.0‰ to 19.8‰ and from ‐67.2‰ to ‐38.4‰, respectively, while δ18O‐H2O values ranged from ‐12.1‰ to +2.7‰ and from ‐9.3‰ to ‐3.6‰, respectively. The Local Meteoric Water Line (LMWL) in the check‐dam catchment was δ2H= 7.35 δ18O + 2.29 (R2=0.93). Furthermore, NO3‐ δ15N and δ18O values in baseflow ranged from ‐2.0‰ to +20.5‰ and from +8.0‰ to +15.6‰, respectively. The results indicated that rainfall was affected by below‐cloud secondary evaporation and caused strong isotopic kinetic fractionation to occur during the falling process. The NO3‐ in runoff mainly derived from the nitrification of soil organic matter (SOM), manure or sewage, for which the proportion of manure or sewage was from 50.5% to 83%.

    更新日期:2018-07-12
  • An insight into land use/cover changes and their impacts in Rib watershed, North‐western highland Ethiopia
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-11
    Desalew Meseret Moges; H. Gangadhara Bhat

    Land use and land cover (LULC) changes have severely threatened ecological and economic sustainability in Highland Ethiopia. A clear insight into its extent and rate is, therefore, a crucial step for effective land use planning and decision making. The main objective of this study was to analyze the nature of LULC change and its impacts in north‐western Highland Ethiopia over the last four decades, using the integrated approach of remote sensing and geographic information system (GIS) in combination with field data. Multi‐date Landsat images were used for spatiotemporal change detection through the help of ArcGIS 10.3 and ERDAS IMAGINE 2014 software. A pixel‐based statistical analysis was used to measure class‐to‐class changes and total losses and gains of each LULC class during the study period. The results showed that a significant and widespread change of LULC has occurred in the study area during the period 1973‐2016. The cropland, grassland, and shrubland were the dominant LULC types taking more than 95% in total over the entire study period. The cropland and built‐up land showed a significant increase from 1973 to 2016, whereas grassland and shrubland decreased gradually over the same time period. The LULC change in the study area has caused severe environmental degradation, which in turn has affected ecological sustainability, agricultural productivity, food security and rural livelihoods. The results of this study are expected to provide local level current information on the extent, rate, and impacts of LULC change for decision makers seeking to ensure ecological, social and economic sustainability.

    更新日期:2018-07-12
  • Monitoring Land‐use/Land‐cover Changes due to Extensive Gold Mining, Urban Expansion and Agriculture in the Pra River Basin of Ghana, 1986‐2025
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-11
    Alfred Awotwi; Geophrey K. Anornu; Jonathan Arthur Quaye‐Ballard; Thompson Annor

    This study used the Double Cumulative Curve (DCC) and visual image interpretation methods for the selection of spatio‐temporal Landsat data to evaluate the land degradation by anthropogenic activities in the Pra River Basin (PRB) of Ghana. Unsupervised and supervised classification procedures were used to map the Land Use/Land Cover (LULC) distribution from 1986 to 2016. Assessment of LULC showed that the PRB has been subjected to six different rates of land degradation in the years 1986, 2000, 2004, 2008, 2013 and 2016. This is due to increase in settlement, cropland and mining activities to about 130%, 198% and 304% respectively. The Markov‐CA integrated model was successful in predicting LULC distribution in 2016 and the outcomes were comparable to the actual LULC for 2016. The projected LULC for 2025 showed that land degradation is significant in the western and the eastern parts where cropland and forest are respectively converted to mining activity. The northern, southern and middle parts of PRB are expected to experience high settlement expansion, sedimentation in the rivers and cropland expansion respectively. The results will aid natural resources management, planning and sustainable development at PRB. In addition, the research method serves as guideline for other related studies in an attempt to investigate, quantify and project LULC change in forest ecological areas.

    更新日期:2018-07-12
  • ASSESSING SOIL CONTAMINATION AND TEMPORAL TRENDS OF HEAVY METAL CONTENTS IN GREENHOUSES ON SEMIARID LAND
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-11
    Carlos Gil; Rafael Boluda; José Antonio Rodríguez‐Martín; Miguel Guzmán; Fernando del Moral; Joaquín Ramos‐Miras

    Information about the behaviour and temporal evolution of heavy metals in agricultural soils is limited, particularly about greenhouse soils on semiarid lands, which is non‐existent. Western Almería (Southern Spain) is a semiarid land where some 30,000 ha are occupied by greenhouses with high productivity. As these greenhouses are fundamental to the socio‐economic development of this area, they should be maintained and well‐conserved. However, there are indications that long‐term intensive agriculture with considerable agrochemicals use can deteriorate soil quality, which in turn, would reduce productivity and food quality. This study was conducted to investigate soil contamination and the temporal trends of heavy metal concentrations in greenhouse soils of western Almería. Contamination level, availability and sources of metals were evaluated by the extractable fraction percentage, by indices zinc equivalent, geo‐accumulation, enrichment factor and pollution load, and by a correlation analysis between soil properties and metal contents. The results showed that the total contents of Cd, Cu, Ni and Pb, and the available concentration of Cd, Cu, Pb, and Zn, were significantly higher than background levels. Temporal patterns indicated that these elements accumulate in greenhouse soils. After more than 20 years of intensive agriculture, the available concentration of elements, and contamination, had clearly increased.

    更新日期:2018-07-12
  • Comprehensive assessment of soil quality for different wetlands in a Chinese delta
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-10
    Dawei Wang; Junhong Bai; Wei Wang; Guangliang Zhang; Baoshan Cui; Xinhui Liu; Xiaowen Li

    Soil quality is usually considered as a powerful tool to reveal soil degradation status and wetland ecosystem health. It is insufficient to reflect actual soil quality based on soil fertility or heavy metal pollution assessment, respectively. A comprehensive assessment was performed to combine soil fertility and heavy metal contamination together, based on thirteen soil physical, chemical, biochemical indicators and six heavy metals, in the Pearl River Delta of China including urban river wetlands (URW), ditch wetlands (DW), riparian wetlands (RiW) and reclaimed wetlands (ReW). The moderate fertility level was observed based on the minimum data set (MDS), including TN, MBC, TP, TK, sand and salinity. DW soils had significantly higher soil fertility index values than RiW and ReW soils. Low TN, SOC, MBC levels and sandy loam texture revealed potential chemical and biological and physical degradation risks, especially for ReW. In addition, wetland soils were heavily contaminated by heavy metals, particularly for Cd, according to Nemerow Pollution Index. URW soils exhibited significantly higher pollution levels than ReW soils. According to the methodology for comprehensive assessment of soil quality, soil quality belonged to moderate and low grades because of severe heavy metal pollution, following with moderate nutrition level. Consequently, pollution treatment, fertility (e.g., SOC, N, P, and K) and soil texture improvement are crucial to improving soil quality, preventing further degradation and promoting ecological conservation and sustainability of coastal wetlands in the Pearl River Delta.

    更新日期:2018-07-12
  • Quantifying the effects of human activities and climate variability on vegetation cover change in a hyper‐arid endorheic basin
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-10
    Qin Shen; Guangyao Gao; Fei Han; Feiyan Xiao; Ying Ma; Shuai Wang; Bojie Fu

    Quantifying the contributions of human activities and climatic factors to vegetation cover change is critical for sustainable ecosystem and water resources management in arid and semiarid regions. In this study, the temporal‐spatial variations of normalized difference vegetation index (NDVI) in the middle reaches of the Heihe River Basin (a typical arid endorheic basin in China) from 2000‐2015 were detected, and a formal analytic framework was used to quantify the roles of climatic factors and human activities in driving vegetation cover change. The results showed that the study area has undergone evident overall greening with significant increases in NDVI in both oasis and desert areas. The fractional oasis area increased significantly from 22.93% to 27.69%, and the desert area decreased. The overall greening was mainly due to increases of fractional oasis area and NDVI in desert area with contributions of 50.50% and 42.08%, respectively. The increase in regional NDVI was mainly driven by gross domestic product (GDP) and precipitation with contributions of 40.2% and 40.3%, respectively, and the watertable played a secondary role in the NDVI increase with a contribution of less than 20%. This study indicated that human activities (i.e., oasis expansion) in the oasis areas and precipitation in the desert areas played decisive roles in regional NDVI changes. Coordination between expanding oases and maintaining the stability of oasis ecosystems should be reached. This study provides important references that policy makers and stakeholders can use to rationally manage ecosystem restoration and socioeconomic development and prevent land degradation in endorheic basins.

    更新日期:2018-07-12
  • Achieving low‐carbon cattle ranching in the Amazon: “pasture sudden death” as a window of opportunity
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-10
    Marraiane A. Silva; Mendelson Lima; Carlos A. Silva Junior; Gerlane M. Costa; Carlos A. Peres

    Livestock farming is the key sector that can most contribute to low‐carbon agriculture in the Amazon, the region of Brazil that stands most to gain from land‐use intensification and most to lose from further primary habitat loss. Cattle pastures affected by the ‘sudden death’ syndrome, which has decimated exotic grass pastures across seven Amazonian states, have forced cattle ranchers to begin renewing their grazing lands. Vast areas of pasture die‐off create an opportunity to catalyze livestock intensification through public policies. More productive livestock husbandry results in avoided deforestation, mitigation of methane emissions from enteric digestion, and the release of vast previously deforested areas to either more intensive agriculture or forest restoration. This, however, comes with a cautionary note as the much debated promising paradigm of agricultural intensification remains largely untested as a land‐sparing strategy across the humid tropics. Well‐designed government subsidies will, therefore, be required to ensure that thousands of landowners can take advantage of this opportunity with minimal environmental side‐effects.

    更新日期:2018-07-12
  • Land degradation changes in the Yellow River Delta and its response to the streamflow‐sediment fluxes since 1976
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Peng Gao; Yiming Wang; Pengfei Li; Guangju Zhao; Wenyi Sun; Xingmin Mu

    The Yellow River is globally renowned for its high sediment concentration, primarily because it flows over the Loess Plateau, which suffers from severe land degradation mainly in the soil erosion. Vast sediment flows from the Yellow River into the sea through the Yellow River Delta (YRD), largely shaping the YRD. On the basis of remote sensing images and historical hydrological measurements, we investigated the streamflow‐sediment flux from the Yellow River and the land area changes of YRD region from 1976 to 2016. The relationship between the streamflow‐sediment flux from the Yellow River and the land change rate at the YRD was examined. The changes in shape of different parts of the YRD and their influencing factors were also discussed. The results showed that there is a significant correlation between the land change rate at the Estuary region and streamflow‐sediment flux from the Yellow River. Because of ecological environment constructions on the Loess Plateau, the streamflow‐sediment flux, particularly the sediment flux, underwent a decreasing trend. Along with the collapse of sediment flux, the land area of the YRD and the Estuary region increased before 1998 and decreased afterwards. The solidification projects are of great significance to the protection of the Northern River Beach region, but the decreasing trend of the land degradation rate at the Estuary region is unlikely to change. Our results provided a useful reference for the protection of the YRD and prevention of land degradation in the Yellow River Basin.

    更新日期:2018-07-08
  • Sewage sludge as an organic amendment for quarry restoration: Effects on soil and vegetation
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-21
    Vicenç Carabassa; Oriol Ortiz; Josep M. Alcañiz

    Quarry restoration in Mediterranean environments usually needs organic amendments to improve the substrates used for technosol construction. Digested sewage sludges from municipal wastewater treatment plants are rich in organic matter, N, and P and constitute an available and economically interesting alternative for substrate amendment. However, their pollutant burden and labile organic matter content involve an environmental risk that must be controlled. Moreover, ecological succession in restored areas can be influenced by the use of sludge and should be assessed. To minimize these risks, a new sewage sludge dose criterion relating to its labile organic matter and heavy metal content has been established. Sewage sludge doses currently range between 10 and 50 Mg ha−1. In order to verify the suitability of this dose criterion, 16 areas rehabilitated using sewage sludge located in limestone quarries in a Mediterranean climate in Catalonia (NE Spain) have been assessed. These evaluations focused on physicochemical properties of rehabilitated soils, land degradation processes, and ecological succession. In the short term, 6 months after sludge application, an increment of organic matter content in the restored soils was observed, without significant increases in electrical conductivity or heavy metals content, and with a dense plant cover that contributes to effective soil erosion control. Two years after, ruderal plants were still present but later successional species colonized the restored zones in different degrees. These results suggest that sewage sludge, used as a soil amendment according to the proposed methodology, can safely improve technosol quality without constraints that compromise ecological succession.

    更新日期:2018-07-08
  • China's wetlands loss to urban expansion
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-03-23
    Dehua Mao; Zongming Wang; Jianguo Wu; Bingfang Wu; Yuan Zeng; Kaishan Song; Kunpeng Yi; Ling Luo

    Humans benefit from multiple ecosystem services of wetlands, but massive wetland loss has occurred worldwide due to rapid urbanization. To assess the problem, it is necessary to quantify the spatial extent of urbanization‐induced wetland loss. Here, we investigated the amount and pattern of wetland loss in China due to urbanization from 1990 to 2010, based on the China National Land Cover Database (ChinaCover). Our results show that, during these 20 years, China lost 2,883 km2 of wetlands to urban expansion, of which about 2,394 km2 took place in the eastern regions (Northeast China, North China, Southeast China, and South China). The rate of urbanization‐induced wetland loss was 2.8 times higher between 2000 and 2010 (213 km2 year−1) than between 1990 and 2000 (75 km2 yr−1). Of all wetland categories, reservoirs/ponds and marshes suffered the most severe losses. Most of the wetland loss was due to the expansion of urban built‐up areas rather than industrial or transportation lands. Four hotspots of urbanization‐induced wetland loss in China were identified: the Beijing–Tianjin metropolitan region, the Yangtze River Delta, the Jianghan Plain, and the Pearl River Delta. Urbanization and industrialization continue to unfold in China for the next few decades, and the rapid expansion of small‐ and middle‐sized cities and urban traffic networks is expected to encroach on more wetlands. Although great efforts have been made towards wetland conservation in recent years, China must prevent more wetlands from being wiped out by urbanization if the country is to ahieve its sustainable development goals.

    更新日期:2018-07-08
  • ARTISANAL GOLD‐MINING IN A RURAL ENVIRONMENT: LAND DEGRADATION IN KENYA
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-06
    Benjamin Okang' Odumo; Nikos Nanos; Gregoria Carbonell; Manuel Torrijos; Jayanti Purshottam Patel; José Antonio Rodríguez Martín

    Artisanal gold mining (AGM) is one of the most important activities in the districts of Migori and Transmara (Kenya). Gold mining, however, is known to release vast quantities of arsenic and metals (some of which are very toxic like As, Hg, Cd, or Pb), which poses a serious threat to not only miners but also to the ecosystem and local populations. We, herein, determine the concentrations of arsenic and some heavy metals in several sample types (i.e. ore, soil, river sediment and mine‐tailing) collected from the districts of Migori and Transmara. We also employ lichens and mosses as pollution bioindicators. Geostatistical tools and canonical correlation analysis were used to identify the relevant factors that affected arsenic and metal concentrations in the analysed samples. The following concentration ranges were reported in topsoil: As (1‐17250 mg kg‐1), Cd (0.01‐15.10 mg kg‐1), Cu (7‐9238 mg kg‐1), Cr (1‐214 mg kg‐1), Ni (5‐766 mg kg‐1), Pb (3‐1149 mg kg‐1) and Zn (22‐1271 mg kg‐1). It was concluded that the ecosystem in both districts was highly polluted by heavy metals while the arsenic concentrations in topsoil were among the highest reported worldwide. The results of this study provide new evidence on the impact of AGM on the environment and may further contribute to the design of policy measures with the aim of reducing environmental and human health risks associated to AGM activities.

    更新日期:2018-07-08
  • The impact of grazing on seedling patterns in degraded sparse‐elm grassland
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-01
    Yongcui Wang; Lei Chu; Stefani Daryanto; Lixin Wang; Jixiang Lin; Musa Ala

    Over‐grazing by livestock in semiarid ecosystems is one of the main causes of desertification. Although over‐grazing contributes to global environmental challenge, only a few studies have investigated grazing impacts on the composition of species and functional groups of seedling bank. In this study, we determined whether the composition of seedling species and functional groups, as well as the correlations between the seedlings of sparse‐elm (Ulmus pumila var. sabulosa or U. pumila) and other species changed under three grazing intensities in the degraded sparse‐elm grassland in the Horqin Sandy Land, China. Species composition and abundance of established seedlings were surveyed and the relationships between seedlings of U. pumila and other species were analyzed. The results showed that plant communities under moderate grazing were more stable than the other two grazing intensities due to higher seedling density, higher species richness, and higher number of perennial herbs. Seedlings of U. pumila could even prevent noxious seedlings growth under moderate grazing. We concluded that moderate grazing could benefit the recovery of this sparse‐elm grassland in the Horqin Sandy Land.

    更新日期:2018-07-04
  • Increased access to nearby green‐blue areas associated with greater metropolitan population wellbeing
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-03
    Romain Goldenberg; Zahra Kalantari; Georgia Destouni

    Numerous cities in the world have to handle and support increasing populations, with questions remaining concerning good planning strategies for their growth and development. Among these questions, access to nature for urban residents has been the subject of increased scrutiny in recent years. We here propose and apply a generally applicable new approach to quantitatively investigate the role of close access to natural or nature‐based green‐blue areas for the wellbeing of urban populations. A key novel aspect of this approach is to use income level as a measure of people's possibility to choose their nearby living environment such that it provides them with the highest affordable level of wellbeing. Based on this measure, we concretely investigate possible trends in local green‐blue area access with increasing local income level in the case study example of the Stockholm Metropolitan region in Sweden. For this regional case, we find clear relationships between income level (and related degree of nationality homogeneity) and share of natural/nature based green‐blue areas and man‐made grey areas within walksheds of different population segments. The results point at the importance of maintaining and restoring nearby natural and nature based green‐blue areas as key solutions for increased wellbeing of urban populations; and call for further testing and comparative investigations of local scale associations between socio‐economic descriptors and physical environment in other parts of the world.

    更新日期:2018-07-04
  • Assessing divergent consequences of payments for ecosystem services (PES) on rural livelihoods: A case study in China's Loess Hills
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-03
    Qirui Li; T.S. Amjath‐Babu; Stefan Sieber; Peter Zander

    Payments for ecosystem services (PES) are often used as a tool for arresting land degradation and desertification. Nevertheless, deeper investigation of farm household systems (FHSs) changes during PES projects is rather limited. It is important to understand how various FHSs evolve with the divergent resource allocation strategies aiming at livelihood security in response to the PES scheme. Taking the Grain for Green Project (GGP) in China as an example, the intended and unintended consequences of a PES scheme on land management and conservation are analysed. Using principal component analysis and cluster analysis, FHSs types are identified, while composite indices regarding environmental, economic and food security are created to assess the livelihood security of each type. This is followed by a cost‐benefit analysis that investigates the multidimensional costs and benefits of FHSs types, as well as a regression analysis to explore the determinants of the livelihood security. The results show that seven distinct FHSs types evolved under the GGP PES scheme, with significant differences in livelihood security components. The strategy of setting aside the optimal share of land for ecosystem services, such as erosion reduction, and then compensating the economic loss with permanent and market‐oriented farming activities (greenhouse horticulture and orchards) can establish a positive link between economic development and environmental protection. Findings indicate that careful consideration of market, institutional, and policy interventions for supporting FHSs reorganisation under PES schemes are needed to align the environmental goals with food and economic security goals of farm households, ensuring sustainability of the benefits while limiting the unintended consequences.

    更新日期:2018-07-04
  • A framework for Scaling Sustainable Land Management options
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-03
    R.J. Thomas; M. Reed; K. Clifton; A.N. Appadurai; A.J. Mills; C. Zucca; E. Kodsi; J. Sircely; F. Haddad; C. von Hagen; E. Mapedza; K. Woldearegay; K. Shalander; M. Bellon; Q.B. Le; S. Mabikke; S. Alexander; S. Leu; S. Schlingloff; T. Lala‐Pritchard; V. Mares; R. Quiroz

    Improvements in land use and management are needed at a global scale to tackle inter‐connected global challenges of population growth, poverty, migration, climate change, biodiversity loss, and degrading land and water resources. There are hundreds of technical options for improving the sustainability of land management and preventing or reversing degradation, but there are many socio‐cultural, institutional, economic and policy barriers hindering their adoption at large scale. To tackle this challenge, the Dryland Systems Program of the Consultative Group for International Agricultural Research and the UN Convention to Combat Desertification convened an expert group to consider barriers and incentives to scaling technologies, processes, policies or institutional arrangements. The group reviewed existing frameworks for scaling SLM interventions across a range of contexts, and identified eight critical actions for success: i) plan iteratively, ii) consistently fund, iii) select Sustainable Land Management (SLM) options for scaling based on best available evidence, iv) identify and engage with stakeholders at all scales, v) build capacity for scaling, vi) foster institutional leadership and policy change to support scaling, vii) achieve early benefits and incentives for as many stakeholders as possible and viii) monitor, evaluate and communicate. Incentives for scaling were identified for the private sector, farmers and their communities and policy makers. Based on these findings a new action framework for scaling is presented that analyses the contexts where specific SLM interventions can be scaled, so that SLM options can be screened and adapted to these contexts, piloted and disseminated. The framework can help countries achieve land degradation neutrality.

    更新日期:2018-07-04
  • Managing soil functions for a sustainable bioeconomy – assessment framework and state of the art
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-07-03
    Katharina Helming; Katrin Daedlow; Carsten Paul; Anja‐Kristina Techen; Stephan Bartke; Bartosz Bartkowski; David Kaiser; Ute Wollschläger; Hans‐Jörg Vogel

    Bioeconomy strategies have been adopted in many countries around the world. Their sustainable implementation requires a management of soils that maintains soil functions and avoids land degradation. Only then ecosystem services can be maintained and resources used efficiently. We present an analytical framework for impact assessment that links policy and technology driving forces for soil management decisions to soil processes, soil functional changes and their impacts on ecosystem services and resource use efficiency, both being targets that have been set by society and are anchored in bioeconomy policy strategies and sustainable development goals. While the resource use efficiency concept has a long‐term tradition, most studies of agricultural management do not address the role of soils in their efficiency assessment. The concept of ecosystem services has received increasing attention over the last years; however, its link to soil functions and soil management practices is still not well established. This study is the first to conceptually link the socio‐economic processes of external drivers for soil management with the natural processes of soil functions and connect them back to impacts on the social system. Application of the framework helps strengthen the science‐policy interface and to systemically assess and compare the opportunities and threats of soil management practices from the perspective of goals set by society at different spatial and temporal scales. Insights gained in this way can be applied in stakeholder decision‐making processes and used to inform the design of governance instruments aimed at sustainable soil management within a bioeconomy.

    更新日期:2018-07-04
  • The success story of irrigation against salinity in Violada, NE Spain
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-05-31
    Juan Herrero; Carmen Castañeda

    In the early 20th century, when extensive areas of land were transformed from rainfed to irrigated agriculture, there was a severe lack of scientific and technical literature available on the effects of applying water to saline soils. This was the case of the Violada Irrigation District located in a semiarid region of NE Spain whose transformation started in the 1940s. We discuss the use of agronomical expertise and the limited knowledge of soils available prior to the transformation, the favorable and unfavorable scenarios encountered during the transformation, and the final success of irrigation despite the initial soil salinization and water logging. We attribute the technical success to the fact that gypsum is common in the soils and geological materials, and to the continued drainage efforts. Failures in the irrigation of saline lands are a frequent subject of discussion in the scientific literature; contrariwise, we present the history of a successfully irrigated district after 70 years.

    更新日期:2018-06-30
  • REHABILITATION OF CALCAREOUS SALINE‐SODIC SOIL BY MEANS OF BIOCHARS AND ACIDIFIED BIOCHARS
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-28
    Fardin Sadegh‐Zadeh; Maedeh Parichehreh; Bahi Jalili; Mohammad Ali Bahmanyar

    Saline‐sodic soils comprise a large area worldwide and these areas are increasing annually, therefore, reclamation of these soils is necessary. The present study investigated the effects of adding various biochars and acidified biochars on selected characteristics of saline‐sodic soil and rehabilitation of this soil. The biochars were produced from rice straw (RSB) and dicer wood chips (DWCB) at 300°C. The acidified biochars were prepared by adding HCl to the biochars. The biochars and acidified biochars were incorporated to the soil at 0 and 50 g/kg soil. Soil columns were prepared and saturated from the bottom and then the flow was reversed by keeping a 5 cm constant head of leaching water on top of the columns. The leachates were taken at every one‐third interval of the pore volume fraction. Then, the concentrations of cations and anions, pH, and electrical conductivity (EC) of the collected leachates were determined. At the end of the leaching process, the soil in the column was analyzed for the same parameters as the leachates. The results indicated that the application of the biochars and acidified biochars reduced the soil EC and sodium adsorption ratio (SAR). The biochars, especially the RSB which contains high amount of Ca2+ and Mg2+ were able to remediate the saline‐sodic soil. The Ca2+ and Mg2+ in the biochar can exchange the Na+ on the surface of the soil colloids and therefore, enhance the Na+ leaching from the saline‐sodic soil. Acidified biochar induced CaCO3 dissolution, which will add Ca2+ and H ions to soil solution. The Ca2+ and H+ ions in the soil solution replace the Na+ from the soil colloid surfaces and facilitate the leaching of Na+ from the saline‐sodic soil. From the results, it can be concluded that RSB, ARSB and ADWCB were feasible to ameliorate calcareous saline‐sodic soil.

    更新日期:2018-06-30
  • Efficiency of four different seeded plants and native vegetation as cover crops in the control of soil and carbon losses by water erosion in olive orchards
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-05-23
    Miguel A. Repullo‐Ruibérriz de Torres; Rafaela Ordóñez‐Fernández; Juan V. Giráldez; Javier Márquez‐García; Ana Laguna; Rosa Carbonell‐Bojollo

    Soil erosion is intense on steep slopes, where many olive orchards are located in Mediterranean areas. The adoption of cover crops is a promising soil and water conservation practice for these areas. Nevertheless, there has not been enough information to be able to advise farmers on the selection of plant species. The purpose of this report is to assess different plant species as cover crops to reduce erosion and soil organic carbon loss through sediments. Twenty‐four tests were performed in 6 plots on a 20% slope in southern Spain. A gramineous plant (Brachypodium distachyon), 2 leguminous species (Vicia sativa and Vicia ervilia), and a cruciferous plant (Sinapis alba) were sown and compared with spontaneous vegetation and conventional tillage. Simulated rainfall with intensities of 18.1 (±1.6) and 38.8 (±2.3) mm hr−1 was applied during 2 years. All cover crop treatments, in comparison with tillage, significantly reduced soil and soil organic carbon losses by more than 92%, S. alba being the species with the lowest runoff values. The high rate of soil and water losses observed in the tillage treatment emphasizes the need to protect the soil and its fertility. A kinematic wave model considering variable soil infiltration rates was fitted to the runoff data to evaluate relevant soil and surface characteristics. The estimated saturated hydraulic conductivity and length of the capillary scale were not affected by the treatments, but the surface resistance to water flow indicated the efficiency of S. alba, B. distachyon, and V. ervilia in reducing the runoff velocity.

    更新日期:2018-06-28
  • Ramial wood amendments (Piliostigma reticulatum) mitigate degradation of tropical soils but do not replenish nutrient exports
    Land Degrad. Dev. (IF 7.27) Pub Date : 2018-06-01
    Georges F. Félix; Cathy Clermont‐Dauphin; Edmond Hien; Jeroen C.J. Groot; Aurélien Penche; Bernard G. Barthès; Raphaël J. Manlay; Pablo Tittonell; Laurent Cournac

    Restoring degraded soils to support food production is a major challenge for West African smallholders who have developed local innovations to counter further degradation. The objective of this study was to evaluate a local farmer's technique that uses ramial wood (RW) as soil amendment (Piliostigma reticulatum shrub). Three treatments were applied in an experimental plot in Burkina Faso: control (no amendment), low RW (3 Mg fresh mass·ha−1·yr−1), and high RW (12 Mg fresh mass·ha−1·yr−1). RW was chipped to <5‐cm pieces and either buried or mulched. Topsoil carbon (C), nitrogen (N), and phosphorus (P) in control and low‐RW treatments declined after 7 years of continuous sorghum cultivation. Use of high‐RW amendment stabilized soil C content while N and P declined, thus not replenishing nutrient exports. Net contribution to soil C in the layer measuring 0–15 cm was 15% of the applied C in the high‐RW amendments. Although biomass and grain yields were higher in high‐RW treatments, crop productivity declined throughout the experiment for all treatments. Termite casts on RW treatments evidenced the potential role of wood‐foraging termites in diluting the impact of RW on soil fertility build‐up and soil water content. We conclude that mitigating soil degradation under semiarid conditions in Burkina Faso would require large amounts of woody amendments, particularly if the level of termite activity is high. Additional nutrient sources would be needed to compensate for removal in exported products so that biomass and grain production can be stabilized or increased.

    更新日期:2018-06-27
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
化学 • 材料 期刊列表