华北平原旱稻作物系数试验研究

Crop coefficient of aerobic rice in North China

该文依据2001～2004年4年田间试验资料，利用Penman—Monteith公式计算了北京地区旱稻出苗～成熟期间参考作物蒸散量，并利用农田水量平衡方程及土壤水分胁迫系数计算了作物实际蒸发蒸腾量，由此计算了旱稻各生育阶段的作物系数，并分析了旱稻作物系数变化规律。结果表明；北京地区旱稻出苗～成熟期间参考作物蒸散量平均为560．1mm；日平均孕穗～开花期最高为6．8mm／d，年际变化幅度很小。旱稻作物系数全生育期平均为1．07，在孕穗～开花期最大，为1．49，其次为开花～成熟阶段，平均为1．20，拔节～孕穗最小为0．87；在北京气候背景下，旱稻作物系数与出苗后天数和大于0℃积温具有较好的三次多项式关系。

According to the field experiments from 2001 to 2004, reference crop evapotranspiration in Beijing were calculated by using Penman-Monteith equation and actual crop evapotranspiration were achieved by water balance equation and adjustment coefficient of soil water. Crop coefficients of aerobic rice in different stages were calculated based on the above results. Variations of crop coefficient were also analyzed. The results indicate that average reference crop evapotranspiration during the growth stage in Beijing is 560. 1 mm and the highest daily value in the stage from booting to flowering is 6.8 mm/d with a little variations among years. Average crop coefficient for the whole stage is 1.07. The highest value, 1.49, occurres at the stage from booting to flowering, then the stage from flowering to maturity with the value of 1.20, and the lowest value is at the stage of jointing to booting of 0.87. There is a good relationship among crop coefficient of aerobic rice, the days after emergence, and the cumulative temperature above 0℃.