黄土高原南部水平梯田的土壤水分特征分析

以淳化试区的水平梯田为系统研究对象,休闲坡地为对照,对其剖面土壤水分变化进行动态监测。发现由于作物对梯田土壤水分的吸收利用,以及蒸发散的原因,导致水平梯田的土壤贮水量比休闲坡地小。梯田土壤水分季节变化分为蓄墒期、快速失墒期、补充期和缓慢消耗失墒期4个时期,其剖面分为剧变、活跃、相对稳定4个层次。降水、地形地貌部位、土地利用方式以及梯田宽度与种植年限均对土壤含水量有着不同程度的影响。观测期间,除在梯田表层土壤含水量出现低于有效水的现象外,其它层次都在有效水范围内,无论在丰水、枯水年,梯田土壤中的有效水或中效、易效水都可以满足作物的生长和非生长耗水的需求。

Analysis on Soil Moisture Character of Level Terrace on the South Loess Plateau

Level terrace in Chunhua was the system studied object, fallow sloping field was the check, and their soil moisture variety was dynamic monitored. This research discovered that soil pondage of level terrace were less than fallow sloping filed because of crops'' absorbing and using, and evaporation. There were four seasonal period, they were storing moisture period, rapidly missing moisture period, recruiting moisture period and slowly missing moisture period, respectively, and there were 3 layers, fast changing layer, activity layer and relatively stabilization layer, on terrace soil profile. Rainfall, topography and physiognomy position where terrace located, land utilized mode, terrace width, and planting life affected terrace soil moisture in different degree. In monitoring time, except terrace surface layer had a phenomenon of soil moisture under available water, others were in the range of available water, whenever it was abundance year or year of low water, available, medium available or readily available water of terrace soil can satisfy crop demanding for growth and non-growth cost.