Spatial variations in soil-water carrying capacity of three typical revegetation species on the Loess Plateau, China
Spatial variations in soil-water carrying capacity of three typical revegetation species on the Loess Plateau, China
复制标题
黄土高原三种典型植被恢复树种土壤持水能力空间变异
DOI：
10.1016/j.agee.2018.12.008
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发表时间：
2019-03-01
影响因子：
6.6
通讯作者：
Binley, Andrew
中科院分区：
文献类型：
--
作者：
Jia, Xiaoxu;Shao, Mingan;Binley, Andrew
植被恢复是黄土高原水土流失治理的必要措施。然而，过度的植被恢复会加剧土壤缺水，进而威胁恢复的生态系统的健康和服务。最佳的植物覆盖或生物量（即植被土壤水承载能力，SWCCV）对于区域水平衡、土壤保护和植被可持续性非常重要。本研究的目的是确定黄土高原植被恢复中使用的三种外来树种（刺槐）、灌木（锦鸡儿）和草类（紫花苜蓿）的 SWCCV 空间分布。使用修改后的 Biome-BGC（生物地球化学循环）模型模拟实际蒸散量 (AET)、净初级生产力 (NPP) 和叶面积指数 (LAI) 的动态。使用对研究区域六个地点的三种植物进行现场观察的 AET 来验证模型所需的土壤和生理参数。经验证的模型用于模拟 1961-2014 年期间研究区 243 个代表性地点的三种植物的 AET、NPP 和 LAI 动态。结果表明，平均AET、NPP和LAI的空间分布总体上由西北向东南递增，与年平均降水量（MAP）梯度基本一致。就最大LAI而言，最佳植物覆盖度范围为：刺槐1.1-3.5、科尔欣斯基1.0-2.4、苜蓿0.7-3.0。相应的SWCCV（以NPP表示）为202.4-616.5、83.7-201.7和56.3-253.0 g(-2) yr(-1)。 MAP、年平均气温、土壤质地和海拔是驱动植物种类下SWCCV的主要变量；解释了研究区域超过 86% 的平均 NPP 空间变化。因此，进一步的植被恢复需要根据当前的气候、土壤和地形条件仔细重新考虑。研究结果为指导未来的植被恢复活动提供了植被恢复阈值，确保黄土高原可持续的生态水文环境。
Re-vegetation is a necessary control measure of soil erosion in the Loess Plateau. However, excessive re-vegetation can aggravate soil water shortage, which can in turn threaten the health and services of restored ecosystems. An optimal plant cover or biomass (i.e., soil-water carrying capacity for vegetation, SWCCV) is important for regional water balance, soil protection and vegetation sustainability. The objective of this study was to determine the spatial distribution of SWCCV for three non-native tree (Robinia pseudoacaia), shrub (Caragana korshinskii) and grass (Medicago sativa) species used in the re-vegetation of the Loess Plateau. The dynamics of actual evapotranspiration (AET), net primary productivity (NPP) and leaf area index (LAI) were simulated using a modified Biome-BGC (Bio-Geochemical Cycles) model. Soil and physiological parameters required by the model were validated using field-observed AET for the three plant species at six sites in the study area. The validated model was used to simulate the dynamics of AET, NPP and LAI for the three plant species at 243 representative sites in the study area for the period 1961-2014. The results show that spatial distributions of mean AET, NPP and LAI generally increased from northwest to southeast, much the same as mean annual precipitation (MAP) gradient. In terms of maximum LAI, the ranges of optimal plant cover were 1.1-3.5 for R. pseudoacaia, 1.0-2.4 for C. korshinskii and 0.7-3.0 for M. sativa. The corresponding SWCCV, expressed as NPP were 202.4-616.5, 83.7-201.7 and 56.3-253.0 g(-2) yr(-1). MAP, mean annual temperature, soil texture and elevation were the main variables driving SWCCV under the plant species; explaining over 86% of the spatial variations in mean NPP in the study area. Further re-vegetation therefore needs careful reconsideration under the prevailing climatic, soil and topographic conditions. The results of the study provide a re-vegetation threshold to guide future re-vegetation activities and to ensure a sustainable eco-hydrological environment in the Loess Plateau.