辽西北地区降水不足,春旱严重。年降水量350～470mm,年降水变率高达23%以上,年蒸发量为1700～2200mm,是典型的半干旱地区。同时,该区热量资源有限,无霜期仅110～140天,年≥10℃积温为2400～2900℃。近几年来,随着机耕面积减少,耕深逐渐变浅,水土流失加重,土壤耕层变薄,土壤保水抗旱性能有降低趋势,它影响着作物的生育与产 Precipitation in northwestern Liaoning Province is insufficient, spring drought serious. Annual precipitation 350 ~ 470mm, annual precipitation rate as high as 23%, the annual evaporation of 1700 ~ 2200mm, is a typical semi-arid areas. At the same time, the district has limited heat resources, and the frost-free period is only 110 to 140 days. The accumulated temperature of ≥10 ℃ is 2400 ~ 2900 ℃. In recent years, with the reduction of cultivated area, the depth of tillage becomes shallower, the soil erosion increases, and the soil layer becomes thinner, so the water retention and drought resistance of soil tends to decrease, which affects the crop growth and production