Water-saving management sustains yield of both ordinary paddy rice and drought-resistance rice varieties with reduced irrigation water in ratoon rice production of Central China

Context

Ratoon rice is resource-efficient and environmentally friendly but faces challenges under climate-induced water scarcity. While water-saving irrigation and water-saving and drought-resistant varieties offer promise, their effects on yield and water productivity in ratoon rice system remain unclear.

Objective

To evaluate the effects of water-saving irrigation and drought-resistant rice varieties on yield, yield components, water use, and water productivity in both main and ratoon crops.

Methods

Field experiments were conducted using a split-plot design with two water regimes (continuous flooding [CF] and water-saving [WS]) as main plots and six rice varieties (three water-saving and drought-resistance rice [WDR] and three ordinary paddy rice [OPR] varieties) as subplots in Qichun and Xishui (Hubei, China) in 2023.

Results

Yields were similar between CF and WS across sites, but WS reduced irrigation water use by 76.1–84.6 %, increasing water productivity by 16.3–140.0 %. Main crop yield was comparable between WDR and OPR, but WDR yielded 16.1–30.1 % less in the ratoon crop, resulting in lower water productivity. As a result, water productivity of WDR was significantly lower than that of OPR in ratoon crop but not in main crop. The lower ratoon crop yield of WDR was attributed to reduced total dry weight and a decreased number of panicles per unit area, which was associated with fewer panicles at the lower nodes.

Significance

Water-saving irrigation maintained yield while reducing water input. To improve WDR performance in ratoon systems, future efforts should target enhancing ratoon biomass and promoting tillering from lower nodes.