半干旱黄土丘陵区沙棘林地土壤水分及其对沙棘生长影响研究

Soil Moisture and Its Influence on Seabuckthorn Growth in Semi arid Loess Hilly Region

根据在安塞黄土丘陵沟壑区的观测资料，对５～７ 龄沙棘林地土壤水分及其对生长的影响进行了定量研究， 为提高沙棘林地土壤水分利用率，改善其经营管理提供了科学依据。结果表明：（１） 沙棘根系吸水范围可达２ ｍ 土层以下，在０～２ｍ 土层内沙棘林地土壤水分的垂直变化特点为：随着土层深度的不断加深，土壤含水量呈减小的趋势，在３０～５０ｃｍ 和８０～１００ｃｍ 土层分别出现土壤水分强烈吸收层； （２） 沙棘林地土壤水分的季节变化可分为３个时期：亏缺期、积累期和消退期，１９９８ 年全年雨量分配比较均匀，土壤水分有明显的干、湿季之分； （３） 年生长季中，沙棘生长与其林地土壤水分间有显著的相关关系。

According to the observed data from loess hilly region at Ansai county in 1998, soil moisture of 5~7 year seabuckthorn stands and its influence on seabuckthorn growth are studied.The experimental results showed that:(1) The absorption range of seabuckthorn roots can extend a depth of under 2 m layer, at the scope of 2 m layer, the characteristic of vertical variation of soil moisture of woodlands is that, soil moisture has a tendency of decreasing with the depth of layer increasing, there are two strong absorption layers of soil moisture at 30~50 cm and 80~100 cm layer; (2) The seasonal variation of soil moisture under seabuckthorn woodlands may be divided into three periods: deficient period, accumulative period and lessen period.In 1998, annual precipitation is much even, soil moisture has two obvious seasons of dry and humid; (3) In the annual growth season, the growth of seabuckthorn has marked correlation with soil moisture of woodlands, and seasonal variation of growth falls behind that of soil moisture.