不同龄阶梭梭根区土壤水分时空变化特征

发布时间：2018-11-09 11:19

【摘要】：土壤水是荒漠植被发育最主要的制约因子。不仅影响植物的生长和发育,还限制着植被的种类、数量和分布。梭梭作为北方荒漠区重要的固沙植物,研究梭梭林地土壤水分动态对其植被生存或恢复以及群落稳定性维持具有重要意义。鉴于少有学者研究过不同龄阶梭梭根区的土壤含水率差异,于2014年2月至2014年11月,采用中子仪法和烘干法对0—400 cm沙层土壤含水率进行了原位观测,分析了不同龄阶梭梭根区土壤水分的时空变化规律。结果表明:(1)梭梭根区土壤水分时间变化可分为4个阶段:2月下旬—3月下旬是土壤水分快速补给期,4月上旬—5月下旬是土壤水分均衡期,6月上旬—10月下旬是土壤水分耗损期,11月上旬—次年2月中旬是土壤水分稳定期;(2)梭梭根区0—50 cm土层,受降雨、融雪水入渗补给和蒸发的影响较大,土壤水分变异系数较大且随深度增加迅速减小,50 cm以下土层变异系数较小且随深度变化微小;(3)不同龄阶梭梭根区剖面平均土壤含水率全年与春、夏、秋季均表现为:枯树成熟梭梭中龄梭梭裸地;(4)随距梭梭树干距离的增大(0—5 m范围内),土壤含水率整体呈减小趋势;降雨前后,梭梭根区浅层(0—10 cm)土壤含水率增量大于裸地土壤含水率增量。
[Abstract]:Soil water is the main restricting factor of desert vegetation development. It not only affects the growth and development of plants, but also restricts the species, quantity and distribution of vegetation. Ammodendron ammodendron is an important sand fixation plant in the northern desert area. It is very important to study the soil moisture dynamics in the forest land of Haloxylon ammodendron to survive or restore the vegetation and maintain the stability of the community. In view of the fact that few scholars have studied the difference of soil moisture content in the root region of Haloxylon ammodendron at different ages, from February 2014 to November 2014, the soil moisture content of 0-400 cm sand layer was observed in situ by neutron meter method and drying method. The temporal and spatial variation of soil moisture in the root region of Haloxylon ammodendron at different ages was analyzed. The results showed that: (1) the time variation of soil moisture in the root zone of Haloxylon ammodendron could be divided into four stages: the period of rapid soil water supply from late February to late March, and the equilibrium period of soil moisture from early April to late May. The period of soil moisture depletion is from the first ten days of June to the last ten days of October, and the stable period of soil moisture is from the first ten days of November to the middle of February of the following year. (2) the soil layer of 0-50 cm in the root area of Haloxylon ammodendron was greatly affected by rainfall, infiltration and evaporation of snowmelt water, and the coefficient of variation of soil moisture was larger and decreased rapidly with the increase of depth, but the coefficient of variation of soil layer under 50 cm was smaller and changed slightly with the depth; (3) the average soil moisture content in the root section of different stages of Haloxylon ammodendron was in spring, summer and autumn as follows: bare land for mature Haloxylon ammodendron; (4) with the increase of the distance from the trunk of Haloxylon ammodendron (0-5 m), the soil moisture content decreased, and before and after rainfall, the increment of soil moisture content in shallow layer (0-10 cm) was larger than that in bare soil.
【作者单位】：中国科学院新疆生态与地理研究所荒漠与绿洲生态国家重点实验室;中国科学院大学;
【基金】：国家重点基础研究发展计划项目(2013CB429902) 国家自然科学基金-新疆联合基金面上项目(U1303181)
【分类号】：S714.2

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