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顶凌耙耱是在表土开始化冻但还有冰凌时进行的一项农事活动。在没有灌溉条件的山旱地区,早春顶凌耙耱,保墒防旱,是农业生产上的重要措施。一、为什么要顶凌耙糖?榆林地区冬春干旱多风,表层0～5厘米的土壤水分一般要散失50％左右。土壤开始解冻时,下层水分沿着土壤毛细管源源不断地上升到地面,大量蒸发,整个土层的含水量急剧下降,对春播作物的捉苗和麦苗的返青生长极为不利。通过耙耱,切断表层土壤毛细管,阻止下层土壤水分上升到地面,使冻层融化后的水分更多地蓄存在表层以下的土壤中,起到保墒作用。根据调查资料,早春顶凌耙耱的土地,在表层10厘米内的土壤水分比不耙耱
Top rake is an agricultural activity that takes place when topsoil begins to thaw but still has ice. In mountainous and drought-free areas without irrigation conditions, raking and raking at early spring tops and water conservation and drought relief are important measures in agricultural production. First, why top Ling rake sugar? Yulin winter arid windy, the surface of 0 to 5 cm of soil moisture to lose about 50%. When the soil began to thaw, the lower layer of water along the soil capillary tube continuously rose to the ground, a large number of evaporation, the water content of the entire soil dropped sharply, spring seeding crop seeding and wheat rejuvenation growth is extremely unfavorable. Through the rake 耱, cut off the surface soil capillary tube to prevent the lower soil moisture rose to the ground, so that the frozen thaw water stored more in the soil below the surface, play a role in preserving soil moisture. According to the survey data, early spring Ling raking the land, within 10 cm of the surface soil moisture than not rake