摘要
对甘肃黄土地区４个土类的土壤水分特征、动态及空间变异规律，以及最大吸湿水、凋萎湿度和持水性能的研究表明，土壤水分动态变异规律呈“双峰－双谷”型，据此在时序上可划分为５个明显的时期：（１）春季增失墒交替期；（２）春夏严重失墒期；（３）夏秋墒情恢复期；（４）秋冬缓慢失墒期；（５）冬季墒情稳定期。随着剖面深度的增加，土壤水分的空间变异明显减小，上层土壤服从对数正态分布，而下层及各累积层服从正态分布。
The soil moisture characteristics, dynamic variation and spatial variation in the fields for 4 soils in the loess area of Gansu province, maximum hygroscopicity, wilting point moisture and water holding capacity were studied. The dynamic variation of soil moisture shows 'two peaks -two valleys' type. In view of the above, it may be divided into five periods, i.e., (1) alternative period of wetting and drying in spring;(2) serious water consuming period in spring summer;(3) wetting period in summer autumn;(4) slow water consuming period in autumn winter;(5) stable water content period in winter. The dynamic variation decreased dramatically with depth increase of profile,the moisture variation in the fields for upper layers obeyed logarithmic normal distribution, however, for lower layer and accumulative layers, obeyed normal distribution.
