黑龙港地区的农业干旱风险评估

干旱是黑龙港地区最严重的农业气象灾害,评估冬小麦各生育阶段的干旱风险可为合理制定灌溉制度、采取相应的防旱抗旱措施提供依据。基于验证后的APSIM模型所模拟的1961年-2005年31个点的土壤含水量动态,计算得到了冬小麦各生育期的土壤相对湿度干旱指数,分析了农民方案和优化方案的该地区的农业干旱时空分布特征。结果表明,干旱频率发生较高的时期农民方案中是播种-越冬期和返青-拔节期,分别为48.89%和27.60%;基于"吴桥模式"的优化方案是越冬-返青期、返青-拔节期和灌浆-收获期,干旱发生的频率为51.61%、39.78%和62.22%。易发生干旱的地方多位于邢台、衡水南部和邯郸北部。在冬小麦各生育阶段,干旱指数年际变化显示出两种方案的变化趋势基本一致。尽管总体说来优化方案发生干旱的风险要高于农民方案的,但基于"吴桥模式"的优化方案充分发挥了根系带的土体水库功能,减少了灌溉水,能够高效利用土壤水,如果全区31个点在1961年-2005年间,均按照优化方案灌溉,相比农民方案总共可节水61 785mm,表明"吴桥模式"可在黑龙港地区推广,它在一定程度上可规避干旱风险,同时能达到节水、稳产的目标。

Risk assessment of agricultural drought in Heilonggang District

Drought is the most severe agricultural meteorological disaster in Heilonggang District ,assessment of drought risk during dif‐ferent growing stages of winter wheat may provide basis to determine rational irrigation schedule and to prevent and control drought . Based on the simulated soil water dynamics of 31 profiles for 1961 -2005 using the calibrated APSIM model ,relative soil moisture drought indexes were calculated for different growth stages of winter wheat ,and the spatial and temporal characteristics of agricultural drought of two scenarios ,Farm Scenario(FS) and Optimized Scenario (OS) were analyzed .The results showed that ,from the point of view of different growth stages of winter wheat ,high‐frequency drought occurred in sowing‐overwintering stage and turning green‐joint‐ing stage for FS ,with frequencies of 48.89% and 27.6% respectively ,and in overwintering‐turning green stage ,turning green‐jointing stage and grain filling‐harvesting stage for OS ,with drought frequencies of 51.61% ,39.78% and 62.22% respectively .High drought risk frequently occurred in central region and Xingtai ,south part of Hengshui and north part of Handan .The time series of relative soil moisture drought index in the different growth stages of winter wheat showed the same change trend in the time series of relative soil moisture drought index of two scenarios .This study suggested that ,in general ,the relative soil moisture drought index was higher in FS than OS ,but the OS ,which based on′Wuqiao Mode′,brought the soil root zone reservoir into play enough ,reduced the irrigation water and could use soil water with high efficiency .The total water amount of 61 785 mm could be saved in OS compared to that in FS ,if irri‐gation schedule of the OS was adopted in 31 profiles through the district in the period of 1961-2005 .It showed that′Wuqiao Mode′can be extended to application in Heilonggang District ,and this mode may avoid drought risk in some degree ,and can reach the goal of saving water and maintaining high yield .