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在我国中亚热带典型红壤区通过水稻测坑试验 ,测定了农田水量平衡各分项。结果表明 ,低、中、高水分条件下早稻的蒸散需水量为 36 8.6～ 415 .4mm ,日均蒸散量为 4.2 9～ 4.83mm d。 5月～ 7月的降水总量可以满足早稻的蒸散和渗漏需要 ,并有多余的水分需排出。但由于降雨间隔不匀 ,仍需少量灌水来补充调节。晚稻低、中、高 3种水分状况下蒸散量为 334.9～ 384.2mm ,略低于早稻 ,但日均蒸散量高于早稻。即使雨水偏多年份的降水也不能满足晚稻的生长需要 ,必须灌水补充。在多雨年份淹水灌溉的高水分处理谷物产量比中等水分的要低。早稻低水分使总穗数和千粒重减少 ,每穗总粒数和结实率增加 ;晚稻低水分使结实率和千粒重下降 ,总穗数增加。土壤水分条件对每穗总粒数影响最大 ,对水稻叶片单位面积光合速率的影响无明显一致的规律。
In our country, the typical subtropical red soil area was measured by rice test pit, and the sub-items of farmland water balance were measured. The results showed that the evapotranspiration water requirement of early rice was 36 8.6-415.4 mm, and the average daily evapotranspiration was 4.2 9-4.83 mm d under low, middle and high water conditions. The total amount of precipitation from May to July can meet the needs of evapotranspiration and leakage of early rice, and excess water needs to be discharged. However, due to uneven rains, still need a small amount of irrigation to supplement regulation. The evapotranspiration of late rice under low, middle and high water conditions was 334.9 ~ 384.2mm, slightly lower than that of early rice, but the average daily evapotranspiration was higher than that of early rice. Even if rainfall in many years of precipitation can not meet the growth needs of late rice, irrigation must be added. High-moisture treated grain yields were lower in sub-irrigated and rainy years than moderate water. The low water content of early rice decreased the total number of kernels and 1000-grain weight, and the total grains and seed setting rate increased. The low water content of late rice decreased the seed setting rate and 1000-grain weight, and the total spikes increased. Soil moisture had the greatest effect on the total grain number per panicle, but had no obvious regularity on the photosynthetic rate per unit area of rice.