Faculty of Engineering and Built Environment, University of Newcastle, Callaghan, New South Wales, Australia; Instituto para el Estudio de los Ecosistemas Continentales (IPEEC-CONICET), Puerto Madryn, Argentina; School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia.
Instituto para el Estudio de los Ecosistemas Continentales (IPEEC-CONICET), Puerto Madryn, Argentina.
Sci Total Environ. 2018 Dec 10;644:1399-1408. doi: 10.1016/j.scitotenv.2018.07.052. Epub 2018 Jul 23.
An improved understanding of the drivers controlling infiltration patterns in semiarid regions is of key importance, as they have important implications for ecosystem productivity, retention of resources and the restoration of degraded areas. The infiltration depth variability (ΔInf) in vegetation patches at the hillslope scale can be driven by different factors along the hillslope. Here we investigate the effects of vegetation and terrain attributes under hypothesis that these attributes exert a major control in ΔInf within the patches. We characterise the ΔInf within vegetation patches at a semiarid hillslope located at the Jornada Experimental Range at dry antecedent conditions preceding two winter frontal rainfall events. We measured these events that are typical during winter conditions, and are characterised by low intensity (0.67 and 4.48 mm h) and a total rainfall of 10.4 and 4.6 mm. High precision geo-referenced wetting front depth measurements were taken at various locations within the vegetation patches using differential GPS. Vegetation and terrain attributes were analysed to explain the ΔInf among the vegetation patches. The infiltration depths in the periphery of the patches were in general considerably deeper than those in the centre. The observations suggest that the upslope margin of the patches received additional water in the form of runon from upslope adjacent bare soil. Patch orientation with regard to the slope dictated the effect of the rest of the patch attributes and the distance to the hillslope crest on ΔInf. We found that primarily patch orientation, followed by shape and size modulate lateral surface water transport through their effects on overland flow paths and water retention; something that would be obscured under more simplistic characterisations based on bare versus uniform vegetated soil discrimination.
深入了解控制半干旱地区入渗模式的驱动因素至关重要，因为这对半干旱地区生态系统生产力、资源保持和退化地区恢复具有重要意义。在山坡尺度上，植被斑块的入渗深度变化（ΔInf）可能受到山坡不同位置的不同因素的影响。在这里，我们根据植被和地形属性在斑块内控制ΔInf 的假设，研究了这些属性的影响。在半干旱山坡的植被斑块内，我们在 Jornada 实验范围的干燥前条件下测量了这些事件，这些事件是冬季典型的，其特点是强度低（0.67 和 4.48 mm h），总降雨量为 10.4 和 4.6 mm。在植被斑块内的不同位置使用差分 GPS 进行了高精度的湿锋深度测量。分析了植被和地形属性，以解释植被斑块之间的ΔInf。斑块边缘的入渗深度通常比中心的入渗深度深得多。这些观察结果表明，斑块的上坡边缘以坡面径流的形式从相邻的裸露土壤中获得了额外的水分。相对于坡度的斑块方位决定了其余斑块属性以及与山坡坡顶的距离对ΔInf 的影响。我们发现，主要是斑块方位，其次是形状和大小，通过对漫流路径和水分保持的影响来调节侧向地表水的传输；而在基于裸露土壤与均匀植被土壤的更简单特征的描述下，这些因素可能会被掩盖。
