华中地区稻田水分平衡和稻作灌溉生产效率

华中地区降水季节性强 ,水资源态势具有明显的盈亏期。双季稻作生产灌溉必不可少。近 10年定位测量表明 ,常年灌溉需水量 5 838m3 / hm2 ;年变异 C.V.=8.1%。晚稻灌溉量占全年的 71% ,7— 9月是灌溉需水高峰期 ,占全年灌溉量的 6 8%。本区双季稻作生产灌溉效率 (灌溉水量与产量之比 )为 :生物量 3.6 7kg/ m3 ,精谷量 1.48kg/ m3 ;生长灌溉效率为 :生物量 4.43kg/ m3 ,灌溉水量与生产效率间年变化呈反相关。不同灌溉处理试验表明 :华中双季稻生产的灌溉 ,以早稻保持水层淹灌 ,晚稻按需配额灌溉的模式比较适宜

Balance of Water in Rice Paddy and Irrigation Rate in Central China.

The amount of irrigation water required for rice cropping in central China differs severely among seasons, because there have obvious profit and deficit periods of water resource from rainfalls. Irrigation is essential in double rice systems. Based on field trials over 10 years, water needed by irrigation was about 5838m 3/hm 2(the annual variation efficient of irrigation water required varied 8.1%), of which 17% was consumed by tillage, and 71% by growing late rice. Irrigation between July and September consumed 68% of the total water required. Irrigation production rate 3.67kg/m 3 in rice biomass and 1.48kg/m 3 in grain output. However, the irrigation production rate was little related to the amount of irrigation water. Growth irrigation rate was 4.43kg/m 3 in rice biomass and showed a negative relationship with the amount of irrigation water. It was concluded that for growing double rice in central China, water must kept in early rice and periodical irrigation was very important for late rice.