Diverse water management in a preceding wheat crop does not affect maize yield but increases inter-annual variability: A six-year field study

Abstract

As maize-based crop rotation systems are essential to ensure global food security, understanding the effect of the preceding crops and the associated management on the subsequent maize is crucial. Here we address this view with a 6-year field experiment in the North China Plain's annual winter wheat and summer maize rotation system. Effects of preceding wheat with three water management (conventional irrigation, Con.W/M; optimized irrigation, Opt.W/M; minimum irrigation, Min.W/M) on maize yield and water consumption are investigated. We find that water management in the preceding wheat crop does not affect the subsequent maize yield but increases the interannual yield variability. Over the six years, an average yield of > 10.7 Mg ha-1 is achieved for maize in the three treatments. The highest coefficient of variation (CV) of yield is observed in Min.W/M (12.0%), while there is no significant difference in CV between Con.W/M and Opt.W/M. The annual water consumption follows a decreasing trend in the order of Con.W/M (357 mm), Opt.W/M (332 mm), and Min.W/M (290 mm), which primarily attribute to variations in initial water storage in the deeper soil profile (below 80 cm). The variation in water storage would be eliminated during the following maize growing stages due to ample rainfall in the temperate continental monsoon climate. The findings show that kernel weight (KW) is the primary determinant (accounting for 55–86%) to the observed variations in maize yield. In the Min.W/M treatment, the interactive effect of killing degree days, growing degree days, maximum temperature, and solar radiation accounts for 85% of the variation observed in KW. This study provides insights into the effect of the preceding wheat on the subsequent maize for grain yield and water consumption in the rotation system.