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

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.

Improved Understanding of How Catchment Properties Control Hydrological Partitioning Through Machine Learning

“…PD and SAI used in this study reflect the secondary control factors of climate variability on hydrological partitioning. VP mainly influences transpiration via regulating stomatal conductance (Zhang et al., 2021). These catchments cover diverse climatic and landscape conditions.…”

Trends, Variability, and Drivers of Flash Droughts in the Contiguous United States

“…(2022) showing that one pathway for SMPD development has no ED early warning signal and is referred to as a low severity “stealth” FD which is forced by precipitation deficits, whereas the other two potential pathways do contain excessive ED prior to drought onset. ED has potential for overestimation on the impact of crop yields because RZSM is not explicitly accounted for (Rigden et al., 2020), but research has identified that RZSM and ED co‐regulate stomatal conductance and plant stress is induced under high ED conditions despite having concurrent, high RZSM conditions (F. Zhang et al., 2021; J. Zhang et al., 2021). Reduced stomatal conductance can also increase canopy temperature, causing reduced water use efficiency and heat‐related impacts (Lobell & Gourdji, 2012) and changes in ED are also projected to increase wildfire risks in areas such as California or Nevada (McEvoy et al., 2020).…”

“…The South and West regions have the only statistically significant increasing SMPD trends ( p < 0.01), although trends are small (Table 1). Droughts in these regions have been observed to have become more frequent and longer in duration over the last five decades (F. Zhang et al., 2021; J. Zhang et al., 2021). These two regions have positive T avg trends corresponding with positive trends in EDFD and P int , and negative trends in RZSM, ET, and P avg .…”

Hybrid Neural Network Based Models for Evapotranspiration Prediction Over Limited Weather Parameters

“…A known strategy, to make a water efficient irrigation system, is to rely on soil humidity sensors and keep the humidity levels between the field capacity (FC) and the management allowable depletion (MAD), which is a percentage of the soil available water holding capacity [1]. Apart from components, installation, and management costs associated to the implementation of such systems on public green space, other problems are common such as vandalism or theft, since normally there is no comprehensive security or surveillance in such locations.…”