乌兰布和沙漠固沙梭梭林生长季土壤水分动态研究

Study on Soil Moisture Dynamics in Growing Season of Sand-fixing Haloxylon ammodendron Forest in Ulan Buhe Desert

土壤水分是干旱沙区荒漠植被生长发育的主要限制因子,为了解乌兰布和沙漠固沙梭梭林地的土壤水分动态变化特征,采用烘干法于2021年4—9月对梭梭林生长季土壤水分进行测定。结果表明,梭梭林地0—20 cm土壤含水量0.23%~2.13%,为浅层干沙层;20—80 cm土壤含水量0.36%~3.59%,为中层剧烈变化层;80—120 cm土壤含水量0.45%~1.63%,为深层稳定层。土壤含水量的月变化显示在4月处于土壤水分消耗较弱阶段;5—8月处于土壤水分消耗旺盛阶段;9月处于土壤水分缓慢恢复稳定阶段。土壤水分与土壤水势之间存在明显的对数函数关系(R~2均大于0.514 2)。综上所述,梭梭林地土壤水分垂直分布分层特征明显,时间上变异程度高于空间,具有较强的时间变异性,对该区人工植被建设具有重要意义。

Soil moisture is the main limiting factor for the growth and development of desert vegetation in arid sandy areas.In order to understand the dynamic change characteristics of soil moisture in the sand-fixing Haloxylon ammodendron forest in Ulan Buhe Desert,the drying method was used to measure the soil moisture of Ammodendrus ammodendrus forest during the growing season from April to September in 2021.The results showed that,0—20 cm of Haloxylon ammodendron ammonium forest was shallow dry sand layer with soil moisture content 0.23%~2.13%,20—80 cm was middle layer with severe changes with soil moisture content 0.36%~3.59%,and 80—120 cm was deep stable layer with soil moisture content 0.45%~1.63%.The month change of soil moisture content showed that the soil water consumption was weak in April,was vigorous from May to August,and was slowly restored and stabilized in September.There was an obvious logarithmic function relationship between the soil moisture content and soil water potential(R2 is greater than 0.5142)。In conclusion,the soil moisture in Saxoul woodland had obvious character of vertical distribution and stratification,and the variation degree of time was higher than that of space,which was of great significance for the construction of artificial vegetation in this area.