【摘要】 以米脂县为基点，分析研究了陕北黄土丘陵区时段干旱特征及其对粮食生产的影响，并提出了相应的减灾对策。影响本区粮食生产的主要因子为伏旱、冬春季干旱和７月份降水量。上述因子对气象产量的灰色关联度分别为０．９４、０．６５和０．８１。粮食产量的丰歉关键取决于年内降水是否与农作物的需水规律同步，而与年总降水量无关。更多还原

【Abstract】 with Mizhi county as base ,this paper analyses the characteristics ofperiodic droughts and their effects on grain yields ,and advances the correspondingcountermeasures for reducing disasters in hilly and gully regions on the Loess Plateau.The main constraints which affect grain yields are the hot summer drought , Winter-spring seasonal droughts and the amount of rainfall in July. Their grey incidence degreewith grain yields are 0.94,0.65 and 0. 81 respectively. Grain yields mainly depend onwhether rainfall distribution is in coincidence with crop water requirement patterns,and it is not related to yearly rainfall.更多还原