Effects of long-term controlled irrigation on formation and stability of yield of double-season rice

HU Wanlin; YANG Wei; WANG Ziyan; CHEN Xi; MIAO Tiantian; QIN Xiaobo; ZHU Bo; YI Lixia; WANG Bin

doi:10.13522/j.cnki.ggps.2025192

Abstract：[Objective]Water scarcity and inefficient irrigation are major constraints in paddy rice production,particularly in regions cultivating double-season rice.This paper experimentally investigates the effects of long-term controlled water irrigation on the yield and stability of double-season rice.[Method]The experiment was conducted in a double-season rice field from 2013 to 2019 in Jingzhou City,Hubei Province.There were two irrigation treatments:conventional irrigation(CK)and controlled water irrigation(WI).In each treatment,we measured yield and yield component,biomass,and yield stability indices characterized by the coefficient of variation(CV)and the sustainability yield index(SYI).[Result]Compared with conventional irrigation,controlled irrigation only changed the biomass of early rice by-3.87％to 6.12％,the effective spike numbers by-8.56％to 2.32％,the seed-setting rate by-4.67％to 1.03％,the grain numbers per spike by-9.95％to 5.99％,the 1000-grain weight by-3.54％to-0.54％,the grain yield by-6.69％to 6.70％,and the harvest index by-3.11％to 0.56％.For late rice,controlled irrigation increased the biomass by 0.57％-13.95％,changed the effective spike numbers by-0.21％to 7.46％,seed-setting rate by-1.44％to 8.12％,the grain numbers per spike by-14.12％to 7.08％,the 1 000-grain weight by-0.11％to 2.97％,the grain yield by-0.88％to 9.70％,and the harvest index by-3.72％to 1.97％.Overall,controlled irrigation increased the total yield of double-season rice by 1.07％-7.73％.In addition,controlled irrigation increased the CV of early rice by 10.28％and reduced its SYI by 0.756,while showing no significant effect on late rice.Overall,controlled irrigation did not show a noticeable impact on the yield stability of double-season rice,with the CV of total yield decreasing from 4.83％to 3.79％.Partial least squares path modelling showed that controlled irrigation affected early rice yield negatively and late rice yield positively.Meteorological factors,such as average temperature and rainfall,significantly impacted both yield and biomass of the rice.[Conclusion]Controlled irrigation reduces early rice yield but increases late rice yield.This complementary effect maintains the yield stability of double-season rice.Controlled irrigation is thus a water-saving strategy to sustain paddy fields.