Productivity and water use of ratoon rice cropping systems with water‐saving, drought‐resistant rice

Water-saving, drought-resistant rice (WDR) (Oryza sativa L.) is a type of new rice cultivars with high drought resistance and low water consumption in the production phase. Ratoon rice cropping is regarded as a resource-efficient rice production system with low cost and high profit. The development of ratoon rice system with WDR is conducive to the sustainable production of rice and the expansion of rice plantation; however, no such attempt has been made. In this study, a field experiment was conducted for 2 yr to evaluate the feasibility of developing new ratoon rice cropping systems using WDR compared with using common lowland rice (CLR). The productivity, regenerative capacity, and water use efficiency (WUE) were investigated in the water-saving cultivation system using two WDR cultivars-Jieyou 652 and Jieyou 804-and in the conventional flooding cultivation system using the CLR cultivar Fengliangyouxiang 1. The irrigation WUE for the WDR systems was 89.8-214.8% and 243.4-765.6% higher than for the CLR system in the main and ratoon cropping seasons, respectively. The grain yield was not significantly different in the main cropping season between the WDR and CLR systems; nevertheless, it was lower in the WDR systems because of shorter growth duration and smaller panicles in the ratoon season. Higher accumulations of dry matter (DM), nonstructural carbohydrates (NSCs), and nitrogen in the stubble of main-season crops is helpful to the promotion of regenerative capacity of WDR in the ratoon season.