Abstract:

A field experiment of water and fertilizer regulation was conducted at the Jiangxi Provincial Irrigation Experiment Center Station from 2020 to 2022 to investigate the impacts of water and fertilizer regulation on rice growth and water demands across varying hydrological conditions. The findings revealed that intermittent irrigation resulted in reduced irrigation (by 20.82%), drainage (by 3.93%), leakage (by 16.68%), and evapotranspiration (by 6.77%) compared to conventional irrigation methods during different hydrological years. Evapotranspiration during the late tillering and jointing-booting stages accounted for 40.2% of the total evapotranspiration throughout the growth period. Rice plant height, tiller number, leaf area index (LAI), and dry matter accumulation exhibited consistent dynamic changes across different hydrological years, all being greater under fertilization treatments compared to non-fertilized conditions, with fertilizer application notably affecting yield. However, in drought years, rice yield under intermittent irrigation was lower than that under submerged irrigation, and plant height, tiller number, LAI, dry matter accumulation, rice yield, and evapotranspiration were all restrained. Average irrigation amounts were higher in drought years compared to wet and normal years, while average drainage, leakage, and plant height were lower. Average evapotranspiration of paddy fields was lower in drought years compared to wet years but higher than in normal years, while tiller number, LAI, dry matter accumulation, and rice yield were lower in drought years compared to normal years but higher than in wet years.

Key words: rice growth, drought, water and fertilizer regulation, rice yield, evapotranspiration