杉木人工幼林生态系统土壤水分特征的研究

A Study of Soil Water Characteristics in a Young Cunninghamia lanceolata Hook. Ecosystem

根据森林生态系统定位研究数据，采用土壤本分测值标准差、标准差检验值、相关系数和变异系数．对杉木人工幼林土壤水分的动态特征进行了研究．结果表明：杉木人工幼林与成熟林相比，土壤蓄水能力较弱，水源涵养能力较差，在0～30cm土层，幼林地土壤含水量低于对照地和间伐地，而变幅则高于对照地和间伐地；在较深的根系分布层．情况则相反；幼林地不同层次土壤水分变化相似性趋大，各层次间土壤含水量差异也变小，对水分的调节和缓冲能力变差；依据土壤水分测值标准差、标准差检验值．相关系数和变异系数4个指标，可将土壤水分垂直分布划分为：土壤水分速变层、土壤水分活跃层、土壤水分次活跃层3个层次．并将土壤水分季节变化划分为相对稳定期、补偿期和损耗期.

Based on located research data, the dynamic characteristics of soil water in a young Cunninghamia lanceolata Hook. ecosystem were studied by means of soil water determination indexes: the standard deviation, statistical test of differences of standard deviation, coefficient of variation and coefficient of correlation. Results show that the soil water storage and conservation capacity of the young forest ecosystem are less than those of the mature forest ecosystem; that the soil moisture at the depth of 0-30 cm in the young forest land is lower than that in the contrast and thinning land while its fluctuation is greater; and that at greater depths it is just the opposite case due to the effect of the root system. The similarity .of soil water variation among different depth layers becomes greater in the young forest land,and the difference of soil water content at different layers becomes less, which results in a less regulation and buffed capacity of water. According to the four indexes of soil moisture determination: standard deviation, statistical test of differences of standard deviation coefficient of correlation and coefficient of vertical variation,the soil profile can be divided into three layers:changeable layer, active layer and less active layer.and the annual variation of soil water conditions can also be divided into four periods, i. e.,relatively stable period, recharge period and los.s period.