通过对黄土高原典型残塬董志塬麦田不同时期土壤各层次水分含量的分析,揭示了陇东黄土高原塬区土壤干旱特征。分析显示,麦田土壤从上层到下层,干旱发生频率呈现出逐渐增加的趋势,但干旱强度呈现出逐渐减弱的趋势;重旱主要出现在春末初夏,土壤中、上层出现概率最高,1 m以下土层基本不出现重旱现象;过湿现象主要出现在秋季,土壤中、下层出现概率最高,1 m以上土层基本不出现过湿现象;晚秋是董志塬麦田土壤含水量最丰沛的时期,春末初夏是最干旱的时期,早春出现重旱的几率较小。
In this paper, characteristics of soil aridity in the upland of the Longdong Loess Plateau was determined through the analyses of soil water content of different periods in different layers of wheat field on the typical/Dongzhi Upland0. Analyses indicate that from the top soil layer down to the lower, frequency of soil aridity occurrence gradually increases, but soil aridity degree gradually weakens. Severe soil aridity mostly occurs between the end of spring and the early days of summer, and has the highest probability of occurrence in the upper and middle parts of a soil profile. Usually, severe aridity does not take place below a depth of 1m. Excess wetness mostly occurs in autumn, and has the highest probability in the middle and low parts of a soil prof ile. Usually, ex cess wetness does not take place within 1m of the upper layer. Soil water content in wheat field reaches a maximum in late autumn. The most arid time is betw een the end of spring and early summer. Severe soil aridity takes place with a little probability in early spring.