May conservation tillage enhance soil C and N accumulation without decreasing yield in intensive irrigated croplands? Results from an eight-year maize monoculture

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Highlights

  • Minimum tillage (MT) increased grain yield (+7%) in an 8-year maize monoculture.

  • Maize yield was reduced by no-till (NT) during the initial 5 years, while increased afterwards.

  • NT and MT increased C sequestration by 1.45 and 1.52 Mg ha−1 yr−1 compared with CT.

  • C and N associated to microaggregates within macroaggregates accounted for 41–65 % of total soil C and N under NT and MT.

Abstract

Intensive management of agroecosystems has been widely indicated as major responsible for soil degradation, thus negatively impacting on relationships between agriculture and climate change. Conservation tillage (i.e. no-till and minimum tillage) has been recommended for enhancing soil organic carbon (SOC) and total nitrogen (STN) stocks while having a positive impact on food security, biodiversity, water quality and the environment. Nevertheless, positive responses were mainly reported in hot and semiarid climates, with rainfed crops and low N fertilization rates.

Therefore, the main objective of this study was to test the adoption of conservation tillage in intensive maize cropping systems under temperate soil, with high N fertilization rate (> 200 kg N ha−1 yr−1) and organic matter input (i.e. manure distribution and high biomass return), and with permanent optimum water moisture due to irrigation. We conducted an 8-year field experiment on a maize (Zea mays L.) monoculture to assess: (i) the effect of no-till (NT) and minimum tillage (MT), on grain yield and biomass return as compared with conventional tillage (CT); (ii) how tillage systems affect the evolution of SOC and STN levels over time under these conditions; (iii) soil aggregation processes and mechanisms leading to SOC and STN changes in the long-term. Results showed that MT increased maize grain yield (+7 %) and total biomass (+10 %) compared with CT. Conversely, NT reduced maize grain and biomass production during the initial 5-year transition, but afterwards increased maize yield up to that of CT.

At the end of the experiment, SOC sequestration was increased under NT and MT by 1.45 and 1.52 Mg C ha−1 yr−1 compared with CT, respectively. Also, STN accumulation was higher under NT and MT than under CT (+0.15 and +0.17 Mg N ha−1 yr−1, respectively). Most of such a SOC and STN increase was located into C- and N-rich macroaggregates. Within those macroaggregates (large macroaggregates, LM; small macroaggregates, sM), we found that C and N pools associated to mM accounted for between 41 and 65 % of total C and N content in NT and MT systems across the different soil layers, which is beneficial for long-term C and N stabilization in soils. Thus, introducing conservation tillage within intensive agricultural context devoted to maize monoculture as that of the Po Valley should be recommended to: (i) maintain (or even increase) maize yield, and (ii) enhance SOC and STN accumulation and stabilization.

Introduction

Agriculture has to play a central role for mitigating the unfavorable effects of climate change, by reducing Greenhouse Gases (GHGs) emission to the atmosphere and increasing carbon (C) storage in agricultural soils (UNEP, 2017). At the same time, major needs are restoring soil health conditions and biodiversity (Bouma and McBratney, 2013), as well as enhancing land productivity potential and food production in the context of a rapidly growing human population (Godfray and Garnett, 2014). In the last decades, conventional and intensively managed agro-ecosystems, which depleted most of soil organic matter (SOM), have been widely indicated as major responsible for soil fertility degradation (Triplett and Dick, 2008). Around 45 % of soils in Europe currently have low to very low SOM content (Jones et al., 2012). This is particularly the case of intensively tilled and highly fertilized soils in temperate areas, where predicted future losses may reach the 24 % of the total current SOM stock (Wiesmeier et al., 2016). Thus, introducing sustainable soil management systems able to increase SOM stocks is crucial for enhancing soil fertility and ensuring productivity potential and incomes for farmers (FAO, 2011).

Soil organic matter is mainly composed by soil organic C (SOC), which is a major actor in the natural carbon cycle and represents the largest storage of terrestrial C. Soil organic C also affects soil functions and processes that regulate nutrients release for plants (Troeh and Thompson, 2005). Therefore, increasing the potential of agricultural soils to sequester CO2 as SOC is a key way not only to mitigate global GHGs emission and climate change, but also to enhance soil fertility and food production (Lal, 2004). Similarly, enhancing soil total N (STN) allows to increase productivity potential of soil, as well as to reduce dependency of farmers on chemical fertilizers, which has been recognized as major sources of N pollution into water and air (Hansen et al., 2017).

In the recent past, many studies demonstrated that the increase in SOC and STN levels is primarily related to the return of fresh organic matter to the soil (Kong et al., 2005; Ogle et al;, 2012). Agricultural practices that increase inputs of fresh organic matter to the soil are likely to positively affect SOC and STN levels in agricultural soil (Lützow et al., 2006). The addition of organic fertilizers may further support this process (Bhattacharya et al., 2016). Conversely, physical disturbance of the soil due to tillage usually increases microbial activity and SOM decomposition, thus reducing SOC and STN accumulation (Ogle et al., 2012; Perego et al., 2019). Reducing soil disturbance, which delays the rate of soil aggregates break-down, may stabilize SOM and limit SOC and STN losses (Six et al., 2000a; Wiesmeier et al., 2019).

A recent EU report (European Commission, 2016) defined various strategies to improve C and N cycling at agricultural level. This report includes a series of sustainable (agro)ecosystems managements, for preserving existing C stocks and removing at the same time C from the atmosphere, while having a positive impact on food security, agro-industries, water quality and the environment (Tilman et al., 2002). Conservation Agriculture (CA) has been repeatedly indicated as a recommended way to pursue those objectives (FAO, 2013). However, CA practices in Europe have not taken off yet in any significant scale, especially in intensive agricultural scenarios, and CA adoption is still an ongoing process whose long-term feasibility needs to be evaluated (Soane et al., 2012; Corsi, 2019). In addition, the beneficial effect of CA on crop yield and long-term C sequestration potential has been recently argued (Ogle et al;, 2012; Powlson et al., 2014).

The main objective of this study was to test the adoption of conservation tillage (i) under intensive agro-ecosystems based on maize (Zea mays L.) monoculture, with (ii) high N fertilization rates (> 200 kg N ha−1 yr−1) and organic matter inputs, (iii) permanent optimum soil water moisture due to irrigation, and (iv) temperate climate. Specific objectives were: (1) to measure the effect of contrasting tillage systems (i.e. no-till, minimum tillage, and conventional tillage) on grain yield and biomass input to the soil (biomass return) during an 8-year maize monoculture, and (2) to examine how those tillage systems affect the evolution of SOC and STN levels (i.e. concentration and mass). Physical fractionation techniques were also employed in order to clarify mechanisms behind SOC and STN stabilization in soil aggregates. The following hypotheses were tested: (i) introducing conservation tillage (i.e. no-till and minimum tillage) within intensive agricultural context devoted to maize monoculture - as that of the Po Valley - does not reduce grain yield and biomass return, and (ii) SOC and STN concentration and mass, as well as SOC and STN stabilization within soil aggregates, are highly enhanced under CA in this context.

Section snippets

Experiment and treatments

The field experiment was set up in a commercial farm in Luignano di Sesto ed Uniti, (45°12′24.1″ N, 9°53′23.3″ E; 52 m above sea level), Cremona, Po Valley, Northern Italy. Soil was coarse loamy mixed, superactive, mesic Aquic Haplustepts (Soil Survey Staff, 2014). Main physic-chemical properties of soil are shown in Table 1. Climatic data were collected from the meteorological station positioned in the field. Mean annual temperature ranged between 12.6 and 16.1 °C and cumulative annual

Grain yield and N uptake

Grain yield of maize was significantly affected by tillage treatment (T) and experimental year (Y), as well as by the interaction T × Y (Table 2). Thus, differences among treatments occurred in 7 out of the 8 years of the experiment and varied from year to years (Table 3). Overall, the highest grain yield occurred under MT in 2016, while the lowest under CT and NT in 2013. Specifically, in 2010 and 2011, grain yield was significantly lower under NT than under CT (−16 % and −17 %) and MT (−13 %

Response of maize yield and N uptake to minimum tillage and no-till

In the present study, tillage system significantly affected maize yield, supporting the claim that tillage of soil plays a major role to affect a number of physic-chemical parameters (Tabaglio et al., 2009) that may greatly impact on root development (Fiorini et al., 2018) and plant growth, thus driving changes in crop yield (Fuentes et al., 2009; Aziz et al., 2013). Our results showed that the average grain yield and N uptake of an 8-year maize monoculture decreased in the order MT > CT > NT.

Conclusions

After our 8-year tillage comparison on an irrigated maize monoculture, we concluded that minimum tillage (MT) is a valuable option to increase maize yield and biomass return compared with conventional tillage (CT). This is not the case for no-till (NT), which reduced both maize yield and biomass return during the initial 5-year transition. Nevertheless, our results indicate that, after the negative effects of transition expire, NT may increase maize yield up to the level of CT.

Our results also

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This study is the answer to the increasing worries by researchers, practitioners and farmers regarding the possibility to combine conservation tillage (i.e. NT and MT) and intensive agricultural context as that of the Po Valley. This research was dedicated to the memory of Ernesto Cervi Ciboldi. All activities were supported by the Foundation Romeo and Enrica Invernizzi (Milan, Italy). We would like to thank Cecilia Cervi Ciboldi, the farmer who hosted the field experiment and made this study

References (85)

  • C.E. Clapp et al.

    Soil organic carbon and 13C abundance as related to tillage, crop residue, and nitrogen fertilizer under continuous corn management in Minnesota

    Soil Till. Res.

    (2000)
  • S.B. Dikgwatlhe et al.

    Changes in soil organic carbon and nitrogen as affected by tillage and residue management under wheat-maize cropping system in the North China Plain

    Soil Till. Res.

    (2014)
  • M.S. Dolan et al.

    Soil organic carbon and nitrogen in a Minnesota soil a related to tillage residue and nitrogen management

    Soil Till. Res.

    (2006)
  • K.P. Fabrizzi et al.

    Soil water dynamics, physical properties and corn and wheat responses to minimum and no-tillage systems in the southern Pampas of Argentina

    Soil Till. Res.

    (2005)
  • A. Fiorini et al.

    Effects of no-till on root architecture and root-soil interactions in a three-year crop rotation

    Eur. J. Agron.

    (2018)
  • A. Fiorini et al.

    Combining no-till with rye (Secale cereale L.) cover crop mitigates nitrous oxide emissions without decreasing yield

    Soil Till. Res.

    (2020)
  • D. Guan et al.

    Tillage practices affect biomass and grain yield through regulating root growth, root-bleeding sap and nutrients uptake in summer maize

    Field Crops Res.

    (2014)
  • J.M. Holland

    The environmental consequences of adopting conservation tillage in Europe: reviewing the evidence

    Agric. Ecosyst. Environ.

    (2004)
  • S. Huang et al.

    Long-term effect of no-tillage on soil organic carbon fractions in a continuous maize cropping system of Northeast China

    Pedosphere

    (2010)
  • Y. Kuzyakov et al.

    Review of mechanisms and quantification of priming effects

    Soil Biol. Biochem.

    (2000)
  • D.R. Linden et al.

    Long-term corn grain and stover yields as a function of tillage and residue removal in east central Minnesota

    Soil Till. Res.

    (2000)
  • Y. Lou et al.

    Stratification of soil organic C, N and C: N ratio as affected by conservation tillage in two maize fields of China

    Catena

    (2012)
  • M. Mazzoncini et al.

    Long-term effect of tillage, nitrogen fertilization and cover crops on soil organic carbon and total nitrogen content

    Soil Till. Res.

    (2011)
  • S.M. Ogle et al.

    No-till management impacts on crop productivity, carbon input and soil carbon sequestration

    Agric. Ecosyst. Environ.

    (2012)
  • C. Palm et al.

    Conservation agriculture and ecosystem services. An overview

    Agric. Ecosyst. Environ.

    (2014)
  • A. Perego et al.

    Agro-environmental aspects of conservation agriculture compared to conventional systems: a 3-year experience on 20 farms in the Po valley (Northern Italy)

    Agric. Syst.

    (2019)
  • C.M. Pittelkow et al.

    When does no-till yield more? A global meta-analysis

    F. Crop. Res.

    (2015)
  • A.F. Plante et al.

    Soil aggregate dynamics and the retention of organic matter in laboratory-incubated soil with differing simulated tillage frequencies

    Soil Till. Res.

    (2002)
  • G. Seddaiu et al.

    Long term effects of tillage practices and N fertilization in rainfed Mediterranean cropping systems: durum wheat, sunflower and maize grain yield

    Eur. J. Agron.

    (2016)
  • J. Sheehy et al.

    Impact of no-till and reduced tillage on aggregation and aggregate-associated carbon in Northern European agroecosystems

    Soil Till. Res.

    (2015)
  • J. Six et al.

    Soil microaggregate turnover and microaggregate formation: a mechanism for C sequestration under no-tillage agriculture

    Soil Biol. Biochem.

    (2000)
  • B.D. Soane et al.

    No-till in Northern, Western and South-western Europe: a review of problems and opportunities for crop production and the environment

    Soil Till. Res.

    (2012)
  • V. Tabaglio et al.

    Physico-chemical indicators and microarthropod communities as influenced by no-till, conventional tillage and nitrogen fertilisation after four years of continuous maize

    Soil Till. Res.

    (2009)
  • D.A.N. Ussiri et al.

    Long-term tillage effects on soil carbon storage and carbon dioxide emissions in continuous corn cropping system from an Alfisol in Ohio

    Soil Till. Res.

    (2009)
  • X. Wang et al.

    Tillage and crop residue effects on rainfed wheat and maize production in northern China

    Field. Crop Res.

    (2012)
  • M. Wiesmeier et al.

    Soil organic carbon storage as a key function of soils-a review of drivers and indicators at various scales

    Geoderma

    (2019)
  • A.L. Wright et al.

    Tillage impacts on microbial biomass and soil carbon and nitrogen dynamics of corn and cotton rotations

    Appl. Soil Ecol.

    (2005)
  • Y. Zhang et al.

    No-tillage with continuous maize cropping enhances soil aggregation and organic carbon storage in Northeast China

    Geoderma

    (2018)
  • S. Abiven et al.

    Dynamics of aggregate stability and biological binding agents during decomposition of organic materials

    Eur. J. Soil Sci.

    (2007)
  • N. Blanco‐Moure et al.

    Long‐term no‐tillage effects on particulate and mineral‐associated soil organic matter under rainfed Mediterranean conditions

    Soil Use Manage.

    (2013)
  • H. Chen et al.

    Soil organic carbon and total nitrogen stocks as affected by different land uses in Baden-Württemberg (southwest Germany)

    J. Plant Nutr. Soil Sci.

    (2009)
  • F. Coppens et al.

    Impact of crops residue location on carbon and nitrogen distribution in soil and in water-stable aggregates

    Eur. J. Soil Sci.

    (2006)
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