Managing sodic soils for better productivity and farmers’ income by integrating use of salt tolerant rice varieties and matching agronomic practices
Introduction
Soil salinity–induced land degradation caused by natural and anthropogenic factors, and depletion of fresh water in arid and semi–arid regions remains a major obstacle for realizing sustainable crop production worldwide (Murtaza et al., 2017; Moghimi et al., 2018; Minhas et al., 2019). Presence of excess salts (soluble or exchangeable Na+) in the soil affects all aspects of crop growth and development, including germination, vegetative growth and reproduction. The negative effects of salinity stress are associated with osmotic and ion–specific effects, abnormal pH and nutritional imbalances or a combination of these factors (Almeida et al., 2017; Singh and Sharma, 2018; Evelin et al., 2019). Nearly 1125 million hectare (M ha) of agricultural landscape transcending the continental boundaries is salt affected; of which North and Central Asia, including India accounts for ∼20 % of affected area (Hossain, 2019). In India, about 6.74 M ha (∼4.2 % of total arable lands) area is affected by salinity, sodicity or their combination (Tripathi, 2011). If current trends continue unabated, simple extrapolation suggests expansion of salt–induced land degradation to 16.2 M ha by 2050 (CSSRI Vision 2050, https://www.cssri.org). This problem would be more critical in the Indo–Gangetic region where almost 2.7 M ha of salt affected lands are underlain with poor quality water.
Rice is considered an especially salt–susceptible cereal and the crop response to sodicity stress varies with growth stage (Zeng and Shannon, 2000; Upadhyay et al., 2020). Accumulation of elevated levels of sodium (especially Na2CO3 and NaHCO3) in sodic soils during early seedling stage causes high plant mortality; thereby poor crop establishment and low tillering resulting in significant yield losses (Chunthaburee et al., 2016; Kamran et al., 2020). Extensive field trials also showed yield losses ranging from 36 to 69% in rice cultivated on salt–affected soils in comparison to normal ones (Qadir et al., 2014).
Sustainable management of agricultural ecosystems in stress–prone areas requires climate–smart production systems with effective and affordable management practices. Most farmers apply mined gypsum (CaSO4.2H2O) for soil reclamation to remediate alkali water induced soil sodification. Gypsum provides structural stability (better soil aeration and water movement) by displacing the dispersive Na+ ions with flocculating divalent Ca2+ ions from the exchange sites (DeSutter et al., 2014; Schultz et al., 2017). In recent years, the dwindling availability and declining quality of agricultural grade gypsum has impeded sodic land reclamation projects in many parts of the world, fuelling interest in alternative amendments. Effectiveness of pressmud, an environmentally benign amendment, seems to be an affordable solution to lessening pressure on limited gypsum reserves with appreciable reductions in sodicity related problems and concomitant improvements in yield–related traits (Dotaniya et al., 2016; Sheoran et al., 2020). Pressmud is a soft, spongy and amorphous organic material; helps in dissolution of soil native CaCO3, hasten Na+ displacement, and enhances crop nutrient (Ca2+, Mg2+ and K+) availability with appreciable reductions in soil sodicity. Our previous work also emphasized complementary effects of applying gypsum and pressmud together in reducing the soluble salt load, incipient neutralization of alkalinity, and improving environmental adaptability in rice–wheat rotation under sodic conditions (Sheoran et al., 2021a).
Genetic variation in response to sodicity stress exists within and among crop plants, and adoption of tolerant varieties may offer opportunities to reduce risks of crop loss, and raise productivity by avoiding or resisting the stress conditions and through better plant adaptation (Abbas et al., 2013; Sheoran et al., 2021a, b). This will reduce the dependence on costly amelioration practices, and also benefit the resource–limited farmers inhabiting these areas (Singh et al., 2016).
Farmers’ traditional sodicity management strategies often lead to sub–optimal plant stand; implicating significant yield reductions in salt affected soils (Zeng et al., 2002). Crop management options such as optimum seedling density, plant population and balanced nutrient supply were reported to help mitigate the adverse effects of abiotic stresses following rice transplantation (Moradi and Ismail, 2007; Alam et al., 2013; Gautam et al., 2015; Sarangi et al., 2015). Properly spaced crop efficiently utilize more solar radiation for photosynthesis and absorb more nutrients, ultimately contributing to higher yield (Miah et al., 1990; Singh et al., 2016). Sodic soils generally require additional fertilizers such as nitrogen (N) because of their inherently low N content, dispersed and dissolved organic matter (Marchuk et al., 2013), higher volatilization losses (Cameron et al., 2013), restricted microbial activity and N mineralization (Singh, 2015). Research carried out in India and abroad suggests that crops yield more in sodic soils when supplied with higher N than the amount recommended for non–sodic soils; mainly due to dilution effect and improved salt tolerance (Gupta and Abrol, 1990; Murtaza, 2011; Woyema et al., 2012). It is therefore, critical to determine optimum rates of N for crops grown in salt–affected soils that lead to higher yields and resource–use efficiency.
General recommendations for rice production in normal soils are well established (Rice Knowledge Bank; http://www.knowledgebank.irri.org). However, the effectiveness of integrated soil and crop management practices has not been sufficiently validated under alkaline/sodic (irrigated with high residual sodium carbonate water, RSCiw) soil conditions. To improve current understanding and sustain rice production, it is imperative to re–examine the existing recommendations and develop a set of appropriate management practices to offset yield losses in salt–affected areas. This study aims to (a) understand gypsum and pressmud–mediated improvements in yield and associated morpho–physiological responses, (b) assess the performance of two basmati rice varieties; Basmati CSR 30 (hereinafter designated as CSR30), the first sodicity tolerant basmati rice variety, and Pusa Basmati 1121 (hereinafter designated as PB1121), a high yielding rice basmati variety, over a broad range of soil sodicity and to estimate their threshold sodicity tolerance, and (c) establish proper soil reclamation amendments, crop management practices (number of seedlings hill–1and hill spacing) and optimum amount of N requirement. We hypothesize that integrating the matching (soil, crop and nutrient) agronomic practices with salt (sodicity) tolerant varieties will improve productivity, enhance resource–use efficiency and ensure better economic returns in salt–affected areas. The combination of best management options could then be extrapolated to other areas facing similar challenges.
Section snippets
The study sites
Farmers’ participatory field trials were carried out in selected villages (Mundri, Geong, Kathwar, Sampli Kheri and Bhaini Majra) typically representing sodicity–affected soils of the Ghaghar basin (29.762°–29.838 °N and 76.426°–76.518 °E) of Kaithal district in Haryana, India. The study was conducted during the wet seasons of 2017, 2018 and 2019. Climate is subtropical semi–arid with average annual monsoon rain of 760 mm, most of it received during June–September. The mean minimum temperature
Managing soil sodicity through amendments (FPT–I)
Soil sodicity invariably increased in the plough layer (0–15 cm) when no amendment was used for reclamation; increasing soil pH by 0.19 units and ESP by 6% in comparison to the initial values (soil pH: 8.94 and ESP: 31.7 %; Table 2). In contrast, gypsum applied alone (GR50) and in combination with pressmud (GR25PM5) reduced soil pH by 0.38 and 0.24 units, and ESP by 27 and 21 %, respectively. Application of GR50 and GR25PM5, respectively, improved leaf relative water content (RWC; 4% and 6%),
Discussion
This study is an attempt to develop a set of affordable agronomic and soil management practices to boost rice production and profitability in high RSC water irrigated sodic soils.
Conclusions
This study highlights the impact of adaptive and mitigation strategies for management of sodic soils, involving combinations of genetic tolerance and affordable soil, crop and nutrient management options to bridge the gap in rice yield and to enhance farmers’ income. Compared to traditionally grown PB1121, CSR30 showed better salt tolerance and less yield reduction under sodicity stress (soil pH ≥9.2), with reasonably higher profit margins even under lower soil pH (≥8.2). The study also
Declaration of Competing Interest
The author(s) have no competing interests.
Acknowledgements
We sincerely acknowledge the financial support of the Indian Council of Agricultural Research (ICAR), New Delhi, India through Farmer FIRST Project (NRMACSSRISOL201602600924). The authors are also thankful to the farmers their coordination and support while carrying the participatory research.
References (84)
- et al.
Integrating best management practices for rice with farmers’ crop management techniques: a potential option for minimizing rice yield gap
Field Crops Res.
(2013) - et al.
Physiological and biochemical parameters for evaluation and clustering of rice cultivars differing in salt tolerance at seedling stage
Saudi J. Biol. Sci.
(2016) - et al.
Effects of salinity on sodium content and photosynthetic responses of rice seedlings differing in salt tolerance
J. Plant Physiol.
(2000) - et al.
Effect of simulated flash flooding on rice and its recovery after flooding with nutrient management strategies
Ecol. Engg.
(2015) - et al.
Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants
Plant Physiol. Biochem.
(2010) - et al.
Nitrogen availability regulates proline and ethylene production and alleviates salinity stress in mustard (Brassica juncea)
J. Plant Physiol.
(2015) - et al.
Groundwater irrigation induced soil sodification and response options
Agric. Water Manage.
(2019) - et al.
Effect of drought on leaf gas exchange, carbon isotope discrimination, transpiration efficiency and productivity in field grown durum wheat genotypes
Plant Sci.
(2006) - et al.
Salt tolerance and salinity effects on plants: a review
Ecotoxicol. Environ. Safety
(2005) - et al.
Improved nursery management further enhances the productivity of stress-tolerant rice varieties in coastal rainfed lowlands
Field Crops Res.
(2015)
Ameliorants and salt tolerant varieties improve rice-wheat production in soils undergoing sodification with alkali water irrigation in Indo–Gangetic Plains of India
Agric. Water Manage.
Microbes: the chief ecological engineers in reinstating equilibrium in degraded ecosystems
Agric., Ecosyst. Environ., Appl. Soil Ecol.
Productivity of sodic soils can be enhanced through the use of salt tolerant rice varieties and proper agronomic practices
Field Crops Res.
Effect of salinity on grain yield and grain quality of wheat (Triticum aestivum L.)
Pakistan J. Agric. Sci.
Response of wheat to nitrogen fertilizer at reclaimed high terrace salt affected soils in Sudan
J. Agric. Social Sci.
Plant growth under water/salt stress: ROS production; antioxidants and significance of added potassium under such conditions
Physiol. Mol. Biol. Plants
Regulation of Na+ and K+ homeostasis in plants: towards improved salt stress tolerance in crop plants
Sex. Dev.
Package of Practices for Kharif Crops
Methods of soil analysis: Part–1 physical and mineralogical methods
Nitrogen losses from the soil/plant system: a review
Annals Appl. Biol.
Effect of age and number of seedling, spacing and fertilizer on tall Indica rice
Indian J. Agron.
Rice yield and plant yield variability responses to equidistant spacing
Crop Sci.
Application of flue gas desulfurization gypsum and its impact on wheat grain and soil chemistry
J. Environ. Qual.
Use of sugarcane industrial by-products for improving sugarcane productivity and soil health
Int. J. Recycling Org. Waste Agric.
Comparative performance of multivariable agro-physiological parameters for detecting salt tolerance of wheat cultivars under simulated saline field growing conditions
Frontiers Plant Sci.
Interactive effect of salinity and two nitrogen fertilizers on growth and composition of sorghum
Plant Soil Environ.
Mitigation of salinity stress in plants by arbuscularmycorrhizal symbiosis: current understanding and new challenges
Frontiers in Plant Sci.
Methodology for evaluation of lowland rice genotypes for nitrogen use efficiency
J. Plant Nutr.
Reclaiming tropical saline-sodic soils with gypsum and cow manure
Water
Basmati CSR 30 (Yamini) – the first salt tolerant basmati variety is a boon to the farmers
Technical Bulletin: CSSRI/Karnal/2009/06
Reclamation of highly calcareous saline sodic soil using Atriplexhalimus and by-product gypsum
International J. Phytoremed.
Salt-affected soils: their reclamation and management for crop production
Advances in Soil Science
Soil analysis methods as used in Iowa State College, soil testing laboratory
Iowa Agri.
Incorporating thresholds into understanding salinity tolerance: a study using salt‐tolerant plants in salt marshes
Ecol. Evol.
Present scenario of global salt affected soils, its management and importance of salinity research
Int. Res. J. Biol. Sci.
Genomics, physiology, and molecular breeding approaches for improving salt tolerance
Ann. Rev. Plant Biol.
Chilling tolerance during emergence of cowpea associated with a dehydrin and slow electrolyte leakage
Crop Sci.
Research progress on reduced lodging of high-yield and-density maize
J. Integrative Agric.
An overview of hazardous impacts of soil salinity in crops, tolerance mechanisms, and amelioration through selenium supplementation
Int. J. Mol. Sci.
Associations among characters related to yield sink capacity in spaced-planted rice
Crop Sci.
Plant responses to saline and sodic conditions
Agricultural Salinity Assessment and Management
Factors influencing farmers’ adoption of best management practices: a review and synthesis
Sustainability
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