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沿辽蒙交界,分布着一片高低起伏的沙丘,俗称坨子(图1),其前沿有肥沃的农田。大气降水大部分渗入沙丘,形成地下水,同时在沙丘内,形成大小不一的泡泽,后者又补给地下水。沙丘低地一般均高出前沿农田数十米,因而地下径流可自沙丘源源流入农田底下或呈地下水露头(泉水)。在农田冻结时,地下水强烈上升,甚至高出地面,土壤含水量随之骤增。春融时,农田一片泥泞,使地温回升迟缓,因而这里的春播时间较高兀地要延迟10—20天,最多者达到30天左右,估计损失积温300℃左右,影响农作物的迅速成长。一旦大雨提前降临、或遇早霜、低温冷害,这些农田就会严重减产。
Along the border between Liaoning and Mongolia, there is an area of undulating sand dunes, commonly known as Tuozi (Figure 1), with fertile farmland at its front edge. Most of the atmospheric precipitation into the dunes, the formation of groundwater, while in the sand dunes, the formation of different sizes of bubble, which recharge groundwater. Dune lowlands are generally tens of meters above the forefront of farmland, so that runoff from the source of sand into the farmland or underground water outcrops (springs). When the farmland is frozen, the groundwater rises strongly, even above the ground, and the soil moisture content increases rapidly. Spring melts, farmland a muddy, so that the slow rise in ground temperature, so spring here higher than Wudu to delay 10-20 days, up to 30 days, estimated loss of accumulated temperature of about 300 ℃, affecting the rapid growth of crops. Once heavy rains arrive ahead of schedule, or encounter early frosts and chills, these fields will have a serious cut in production.