三川河流域四县旱情调查

An Investigation into Drought Situations in Four Counties in Sanchuan River Watershed

通过1991年三川河流域四县旱情调查,总结分析了本区伏旱发生规律和抗旱经验。这次旱灾延续时间长,受旱面积大,为历史上罕见。6月中旬～8月中旬降水量比多年平均降水量减少60％,土壤湿度达作物凋萎湿度,梯田坡地1m内平均土壤含水率5.5％～6.3％,作物茎叶凋萎、枯黄,旱灾面积达播种面积的90％以上,减产60％左右。经统计分析:7～8月降水量与历年产量呈正相关,回归方程式为y=49.66+0.655x。主要抗旱措施是:扩大灌溉面积,大力建设基本农田(坝地,梯田)抗旱保墒,调整作物种植结构,适当早播、稀播、调节水供给。

This paper summarized and analysed the laws of summer drought oc-curences and experience in fighting against droughts in Sanchuan River watershedthrough 1991 investigation into drought conditions. The drought damage or disaster last-ed longer from which a large area suffered, which was never known in history. Therewas a 60% of reduction in rainfall from the second decado of June to the second decadeof August in comparison with that of many years on average. As a result,soil humidityreached the wilting humidy of crops. Soil moisture contents in 1-meter-deep soil layerin terraces and slopplands was 5.5 %～6.3%. Accordingly,crop stems and leaves becamewilting and yellow. Drought demaged area accounted for over 90% of sown area with areduction of 60% or so in crop yields. Through statistics analysis,rainfall in July andAugust is in the positive correlation with crop yields for many years. The regression e-quation has Y=49.66+0.655X. The principal drought resistance measures are:enlarge-ment of irrigation area,construction of basic farmlands, readjustment of crop plantingstructures,right in early sowing and thin sowing and regulation of water supplies.