不同灌溉模式下稻田降雨利用和径流量试验

对广西桂林不同降雨频率与不同灌溉方式下的降雨利用、径流量分析研究表明,晚稻降雨利用率远高于早稻;早稻在"薄、浅、湿、晒"、间歇灌溉、传统灌溉模式下降雨利用率随降雨频率的增加呈缓慢上升趋势,而晚稻节水灌溉模式下呈上凸趋势;早稻全生育期和晚稻分蘖期、拔节期径流量很大,对肥料流失产生不利影响.节水灌溉模式能够提高降雨利用率,减少地表径流量.在干旱水文年份,早、晚稻间歇灌溉较其他灌溉方式提高降雨利用率,减少地表径流量更显著.

Experiment study on relation of rainfall utilization and runoff in paddy fields under different irrigation regimes

Based on the experimental data from Guilin Irrigation Experiment Station in Guangxi Autonomous Region,the relation of rainfall utilization and surface runoff in paddy fields under different rainfall frequency and different irrigation regimes is studied;i.e.combining shallow water depth with wetting and drying(SWD),intermitted submerged irrigation(ISI) and traditional flooding irrigation(FI).The research results show:(1) the late rice used more rainfall water than early rice;(2) with the increasing of rainfall frequency,the rainfall utilization coefficient for early rice could improve slowly under all irrigation regimes;but for late rice,the change in rainfall utilization is showed as convex curves under water saving irrigation regimes;(3) the surface runoff is large for the whole growth season of early rice,and only two stages, i.e.tillering and booting of late rice,thus resulting in the losses of nutrients.In conclusion,the water saving irrigation regimes can improve rainfall utilization and reduce surface runoff as well.In the drier years,the ISI performed better than other irrigation regimes for both early and late rice in terms of rainfall utilization and surface runoff reduction.