北京地区旱稻作物需水与降水的耦合分析

基于4a的田间试验资料，采用农田水分平衡法确定了旱稻出苗后各生育阶段的需水量；利用1971年-2000年北京地区逐日降水资料，计算了旱稻各生育阶段在不同降水保证率下的降水量，并选取25％、50％、75％和95％保证率作为典型的湿润年、平水年、干旱年和极枯水年，进行旱稻各生育阶段降水与作物需水的耦合度分析和补灌量估算。结果表明：旱稻出苗后总需水量平均为596.1 mm，需水强度平均为4.3 mm/d，需水强度峰值出现在孕穗-抽穗阶段。4种降水年型下旱稻出苗后降水和旱稻需水的耦合度分别为0.82、0.71、0.50和0.39，所需的补灌量分别为106.6、171.1、296.0和363.9 mm。

Analysis of coupling degree between crop water requirement of aerobic rice and rainfall in Beijing areas

Based on the field experimental data in four years, crop water requirement of aerobic rice at every growth stage was determined by soil water balance method. The rainfall amounts in growing season of aerobic rice were calculated under different precipitation probabilities using the weather data in Beijing from 1971 to 2000. For the analysis of the coupling degree between crop water requirement of aerobic rice and rainfall, the guaranteed rates 25%, 50%, 75% and 95% were chosen as typical humid, normal, droughty and extremely droughty year styles, respectively. Using the coupling degree, the supplemental irrigation amount at every growth stage was estimated under four precipitation year styles. Results show that mean value of crop water requirement on aerobic rice was 596.1 mm and the mean ET_c intensity was 4.3 mm/d during entire growing season. The peak values of ET_c intensity occurred at booting ~ earing stage. Under four precipitation year styles, the coupling degrees between crop water requirement and rainfall were 0.82, 0.71, 0.50 and 0.39, respectively. The supplemental irrigation amounts under four precipitation probabilities were 106.6 mm, 171.1 mm, 296.0 mm and 363.9 mm, respectively.