Sustainable irrigation based on co-regulation of soil water supply and atmospheric evaporative demand

Jingwen Zhang,Yi Yang,William L Bauerle,Derek M Heeren,Grace L Miner,Ming Pan,Daran R Rudnick,Hyungsuk Kimm,Robert F Grant,Wang Zhou,Andrew E Suyker,Trenton E Franz,Chongya Jiang,Bin Peng,Kaiyu Guan

doi:10.1038/s41467-021-25254-7

Abstract

Irrigation is an important adaptation to reduce crop yield loss due to water stress from both soil water deficit (low soil moisture) and atmospheric aridity (high vapor pressure deficit, VPD). Traditionally, irrigation has primarily focused on soil water deficit. Observational evidence demonstrates that stomatal conductance is co-regulated by soil moisture and VPD from water supply and demand aspects. Here we use a validated hydraulically-driven ecosystem model to reproduce the co-regulation pattern. Specifically, we propose a plant-centric irrigation scheme considering water supply-demand dynamics (SDD), and compare it with soil-moisture-based irrigation scheme (management allowable depletion, MAD) for continuous maize cropping systems in Nebraska, United States. We find that, under current climate conditions, the plant-centric SDD irrigation scheme combining soil moisture and VPD, could significantly reduce irrigation water use (−24.0%) while maintaining crop yields, and increase economic profits (+11.2%) and irrigation water productivity (+25.2%) compared with MAD, thus SDD could significantly improve water sustainability.

Highlights

Irrigation is an important adaptation to reduce crop yield loss due to water stress from both soil water deficit and atmospheric aridity
The greenhouse measurements of maize indicated that stomatal conductance increased with soil moisture and decreased with vapor pressure deficit (VPD) in the co-regulated regime, while it was mainly driven by VPD in the VPD-dominated regime (Fig. 2a, b)
Our study proposed and implemented the plant-centric SDD irrigation scheme based on the plant water supply-demand dynamics, i.e., the co-regulations of soil moisture and VPD on stomatal conductance

Summary

Introduction

Irrigation is an important adaptation to reduce crop yield loss due to water stress from both soil water deficit (low soil moisture) and atmospheric aridity (high vapor pressure deficit, VPD). Under current climate conditions, the plant-centric SDD irrigation scheme combining soil moisture and VPD, could significantly reduce irrigation water use (−24.0%) while maintaining crop yields, and increase economic profits (+11.2%) and irrigation water productivity (+25.2%) compared with MAD, SDD could significantly improve water sustainability. This study has three objectives: (1) to investigate the coregulation of the soil moisture and VPD on stomatal conductance of maize using field measurements and a validated process-based ecosystem model; (2) to propose a plant-centric irrigation scheme for sustainable irrigation based on the co-regulation pattern; (3) to test and compare the plant-centric irrigation scheme with soil moisture-based management allowable depletion (MAD) irrigation scheme under current climate and the representative concentration pathway 8.5 (RCP-8.5) scenario. The innovation of this study is to apply the co-regulation pattern into irrigation management, and we find the proposed method has demonstrated a large improvement over the existing soil moisture-only irrigation metrics and could have significant contributions to water sustainability

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Methods

Results

Conclusion