Long-term crop rotation diversification enhances maize drought resistance through soil organic matter

Leah L R Renwick,William Deen,Timothy M Bowles,Matthew E Gilbert,Lucas Silva,Toby Maxwell,Amélie C M Gaudin

doi:10.1088/1748-9326/ac1468

Abstract

Climate change adaptation requires building agricultural system resilience to warmer, drier climates. Increasing temporal plant diversity through crop rotation diversification increases yields of some crops under drought, but its potential to enhance crop drought resistance and the underlying mechanisms remain unclear. We conducted a drought manipulation experiment using rainout shelters embedded within a 36-year crop rotation diversity and no-till experiment in a temperate climate and measured a suite of soil and crop developmental and eco-physiological traits in the field and laboratory. We show that diversifying maize-soybean rotations with small grain cereals and cover crops mitigated maize water stress at the leaf and canopy scales and reduced yield losses to drought by 17.1 ± 6.1%, while no-till did not affect maize drought resistance. Path analysis showed a strong correlation between soil organic matter and lower maize water stress despite no significant differences in soil organic matter between rotations or tillage treatments. This positive relationship between soil organic matter and maize water status was not mediated by higher soil water retention or infiltration as often hypothesized, nor differential depth of root water uptake as measured with stable isotopes, suggesting that other mechanisms are at play. Crop rotation diversification is an underappreciated drought management tool to adapt crop production to climate change through managing for soil organic matter.

Highlights

Climate change will magnify the already persistent global challenge of crop yield loss to drought [1, 2]
The drought experiment was conducted in first-year maize in three 4year rotations along a rotation diversity gradient previously found to span the range of maize yield in hot and dry years [11]: maize-maize-soy-soy (MMSS), maize-maize-soy-wheat (MMSW), and maize-maizeoat/red clover-barley/red clover (MMOrcBrc)
Dynamics and severity of drought stress The imposed drought spanned maize flowering by 1 month on either side

Summary

Introduction

Climate change will magnify the already persistent global challenge of crop yield loss to drought [1, 2]. Yield sensitivity and cereal production losses to drought have increased in recent decades, including for major global crops such as maize [3, 4]. Crop diversity lowers risk through the widely studied portfolio effect whereby different crops respond differentially to stress [8], and possibly through emergent ecosystem properties like improved functioning and resilience, i.e. greater longterm stability due to higher resistance to abiotic or biotic stress and/or faster recovery [9]. Long-term experimental sites including where this experiment took place show that diversification of temperate maize-based crop rotations increases yield, improves yield stability, and helps mitigate effects of weather variability on maize yield, in hot and dry years and in no-till systems [11, 12]. The soil-plant mechanisms underlying greater crop drought resistance through adoption of these ecological intensification strategies have not been experimentally tested

Methods

Results

Discussion

Conclusion