Work

Optimizing irrigation thresholds for water conservation and yield stabilization of maize under varying salinity conditions in Northwest China

Year: 2026

Type: article

Abstract: Identifying optimal irrigation thresholds in arid and saline regions is crucial for sustainable agriculture. However, the optimal irrigation thresholds for maize under different salinity conditions in northwest China remain unclear. Although the APSIM model is widely used in crop management, its application in saline environments has been limited. The DCaPST module couples leaf and canopy photosynthesis with crop growth, and is suitable for evaluating photosynthetic manipulations. This study calibrated the APSIM-DCaPST model using two years of field data and modified crop lower limit (CLL), water-extraction coefficient (KL), and root exploration in soil profile (XF), respectively, under saline stress. The improved model, combined with the TOPSIS method, identified optimal irrigation thresholds for water-saving, yield-stabilizing, and high water productivity (WP) under varying salinity levels. Six photosynthetic parameters were increased by 20% to assess their combined effects on irrigation thresholds, yield, and WP. The APSIM model accurately simulated maize production under non-saline conditions. Integrating DCaPST slightly improved simulations of biomass, yield, and evapotranspiration (ET), but its performance under salt stress remained limited. Adjusting CLL, KL, and XF all improved model accuracy, while KL minimized biomass, yield, and ET simulation errors. Under non-saline conditions, the optimal irrigation threshold was 50%-100% of field capacity (FC); under saline stress (electrical conductivity of the soil saturation extract, EC e = 2, 4, 6 dS m −1 ), they were 60%-100% FC. Notably, at EC e = 6 dS m −1 , the lower threshold could be increased to 70% FC when yield maximization was prioritized over water saving. A simultaneous 20% increase in the maximum carboxylation rate of phosphoenolpyruvate, the maximum electron transport rate, and mesophyll conductance did not change the optimal irrigation thresholds but increased yield by 1.12%-1.85% and WP by 0.17%-1.85%. Under photosynthetic manipulations, the optimal irrigation threshold saved water by 11.59%-41.82% and generally improved WP by 0.31%-6.39% (except for ZD958 at EC e = 6 dS m −1 ), despite a yield reduction of 4.34%-21.21%. These findings provide guidance for sustainable saline agriculture and efficient management of water resources.

Source: Agricultural Water Management

DOI: 10.1016/j.agwat.2026.110398