Spatial and temporal variation of soil moisture in dependence of multiple environmental parameters in semi-arid grasslands
Spatial and temporal variation of soil moisture in dependence of multiple environmental parameters in semi-arid grasslands
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DOI：
10.1007/s11104-010-0692-8
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发表时间：
2011-01
期刊：
影响因子：
4.9
通讯作者：
K. Schneider;U. Leopold;Friederike Gerschlauer;F. Barthold;M. Giese;M. Steffens;C. Hoffmann;H. Fred
中科院分区：
文献类型：
--
作者：
K. Schneider;U. Leopold;Friederike Gerschlauer;F. Barthold;M. Giese;M. Steffens;C. Hoffmann;H. Fred
草地放牧改变了土壤的物理和化学性质以及植被特征，如植被覆盖、物种组成和生物量生产。因此，养分分配和水分储存在表层土壤中的影响。土地使用和管理的变化改变了这些过程。由于草原对碳固存的全球重要性，有必要了解放牧管理对养分和水通量的影响。土壤水分是半干旱地区物质通量和土壤-植被-大气相互作用的限制因子。因此，需要了解放牧管理和载畜量对土壤水分时空分布的影响。在本研究中，我们解决的问题是如何时空土壤水分分布放牧和未放牧的草地网站是受土壤和植被特性。这项研究发生在内蒙古锡林河流域（中国）。这是一个半干旱草原环境，其特点是仍然适度放牧相比，在内蒙古中部的其他地区。然而，当地的放牧率有所增加，导致锡林河上游流域的土壤和植被退化。我们使用多变量地统计学方法来揭示土壤水分分布和土壤或植被参数之间的空间依赖关系。总体而言，7个土壤和植被参数（容重，砂，粉砂和粘土含量，平均重量直径，平均碳含量的土壤，植被覆盖）和57个土壤水分数据集记录在100个网格点上的四个网站，受到不同的放牧强度。增加载畜率加速了土壤和植被参数对土壤水分的影响。然而，相关性是相当弱的，除了一个网站与高载畜率较高的相关性被发现。低块金率表明土壤或植物参数和土壤水分之间的空间依赖性在一个长期未放牧的网站。然而，没有发现的影响，第二个未放牧的网站，已被排除在放牧较短的时间。此外，最重要的土壤和植被参数预测土壤水分分布不同的放牧强度。因此，使用次要变量预测土壤湿度需要仔细选择土壤或植被参数。
Grazing of grasslands changes soil physical and chemical properties as well as vegetation characteristics, such as vegetation cover, species composition and biomass production. In consequence, nutrient allocation and water storage in the top soil are affected. Land use and management changes alter these processes. Knowledge on the impacts of grazing management on nutrient and water fluxes is necessary because of the global importance of grasslands for carbon sequestration. Soil water in semi-arid areas is a limiting factor for matter fluxes and the intrinsic interaction between soil, vegetation and atmosphere. It is therefore desirable to understand the effects of grazing management and stocking rate on the spatial and temporal distribution of soil moisture. In the present study, we address the question how spatio-temporal soil moisture distribution on grazed and ungrazed grassland sites is affected by soil and vegetation properties. The study took place in the Xilin river catchment in Inner Mongolia (PR China). It is a semi-arid steppe environment, which is characterized by still moderate grazing compared to other regions in central Inner Mongolia. However, stocking rates have locally increased and resulted in a degradation of soils and vegetation also in the upper Xilin River basin. We used a multivariate geostatistical approach to reveal spatial dependencies between soil moisture distribution and soil or vegetation parameters. Overall, 7 soil and vegetation parameters (bulk density, sand, silt and clay content, mean weight diameter, mean carbon content of the soil, vegetation cover) and 57 soil moisture data sets were recorded on 100 gridded points on four sites subject to different grazing intensities. Increasing stocking rates accelerated the influence of soil and vegetation parameters on soil moisture. However, the correlation was rather weak, except for a site with high stocking rate where higher correlations were found. Low nugget ratios indicate spatial dependency between soil or plant parameters and soil moisture on a long-term ungrazed site. However, the effect was not found for a second ungrazed site that had been excluded from grazing for a shorter period. Furthermore the most important soil and vegetation parameters for predicting soil moisture distribution varied between different grazing intensities. Therefore, predicting soil moisture by using secondary variables requires a careful selection of the soil or vegetation parameters.