Unstable crop yields reveal opportunities for site-specific adaptations to climate variability

Rafael A Martinez-Feria,Bruno Basso

doi:10.1038/s41598-020-59494-2

Abstract

Water deficit and water excess constitute severe stresses that limit crop yield and are likely to intensify as climate becomes more variable. Regional crop production aggregates for the US Midwest indicate widespread yield losses in past decades due to both extreme rainfall and water limited conditions, though the degree to which these weather impacts are related to site-specific factors such as landscape position and soils has not been examined in a systematic manner. This study offers observational evidence from a large sample of commercial crop fields to support the hypothesis that landscape position is the primary mediator of crop yield responses to weather within unstable field zones (i.e., zones where yields tend to fluctuate between high and low, depending on the year). Results indicate that yield losses in unstable zones driven by water excess and deficits occur throughout a wide range of seasonal rainfall, even simultaneously under normal weather. Field areas prone to water stress are shown to lag as much as 23–33% below the field average during drought years and 26–33% during deluge years. By combining large-scale spatial datasets, we identify 2.65 million hectares of water-stress prone cropland, and estimate an aggregated economic loss impact of $536M USD yr−1, 4.0 million tons yr−1 of less CO2 fixed in crop biomass, and 52.6 Gg yr−1 of more reactive N in the environment. Yield stability maps can be used to spatially implement adaptation practices to mitigate weather-induced stresses in the most vulnerable cropland.

Highlights

Water deficit and water excess constitute severe stresses that limit crop yield and are likely to intensify as climate becomes more variable
To test the hypothesis that landscape position is the primary mediator of crop yield responses to weather within unstable field zones, we examine a set of 305 corn and soybean fields in five Midwestern states (Fig. 1a; Table S1), segmented according to site-specific yield stability and landscape position classifications (Fig. 1b,c)
When variance components are calculated for each field independently, we find that those fields where soil explains little of the variance are in those where the weather-year and landscape position interactions hold the greatest explanatory power (Fig. S2)

Summary

Introduction

Water deficit and water excess constitute severe stresses that limit crop yield and are likely to intensify as climate becomes more variable. Analyses of crop production aggregates for the region have indicated substantial yield losses during drought, and in years with excess rainfall[4,5,6] Both water deficits and water excess constitute severe stresses that limit crop growth and yield. Recent high-resolution crop yield estimates derived from satellite imagery[13] have indicated that about 28% of all corn and soybean cropland in the Midwest is temporally unstable, meaning that yields in these zones tend to fluctuate between high and low, depending on the year These shifts between favorable and unfavorable growing conditions in unstable subfield zones could be explained by patterns of overland water flow and accumulation[14,15]. Our aim is to provide a baseline for the potential improvements in yield and resilience that may be achieved by site-specific implementation of management or genetic adaptations

Objectives

Methods

Results

Conclusion