Spatial distribution of argan tree influence on soil properties in southern Morocco
Spatial distribution of argan tree influence on soil properties in southern Morocco
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DOI：
10.5194/soil-7-511-2021
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发表时间：
2021-08
期刊：
影响因子：
6.8
通讯作者：
Mario Kirchhoff;Tobias Romes;I. Marzolff;M. Seeger;Ali Aït Hssaine;J. Ries
中科院分区：
文献类型：
--
作者：
Mario Kirchhoff;Tobias Romes;I. Marzolff;M. Seeger;Ali Aït Hssaine;J. Ries
抽象的。摩洛哥南部特有的阿干树（Argania spinosa）种群由于过度砍伐、非法砍伐木柴和集约农业的扩张而高度退化。孤立的树木之间的裸露区域由于有限的再生而增加;然而，尚不清楚树木是否会影响树间区域的土壤。从理论上讲，林间区土壤参数的空间差异应是由于枯枝落叶或土壤颗粒（径流和侵蚀或风吹）从树冠覆盖区转移到林间区。在树木周围，从树干沿着树木滴水线（树木区域内外）和两棵树之间的树间区域，在四个方向（上坡、下坡和平行于斜坡的两个方向），直至距离树木50 m处，共采集了385个土壤样本。测定了土壤含水量、pH值、电导率、渗透稳定性、全氮含量、有机碳含量和C/N比。共进行了74个张力圆盘入渗仪试验，在树木滴灌线附近，树区内外，测量非饱和导水率。我们发现树对其周围树间区域的影响是有限的，例如，从树干（4.4%SOC和0.3%TN）到树体滴水线（2.0%SOC和0.2%TN），土壤有机碳和全氮含量显著降低.然而，树滴水线附近的树间面积（1.3%SOC和0.2%TN）与两棵树之间的树间面积（1.0%SOC和0.1%TN）差异显着，但只有很小的影响。由于风漂流和斜坡冲刷，空间格局的趋势可以在东部和下坡方向发现。土壤含水量最高的北部，由于正午阳光的阴影，影响延伸到树间地区。在树体滴灌线附近，树体内外的非饱和导水率也存在显著差异。在不同土地用途（森林畜牧业和农业）、坡度或树木密度下的地点情况就是如此。虽然只有有限的影响，它的树间面积被发现，树周围的空间格局表明，造林措施应针对周围的树木庇护所在北方或东部方向具有较高的土壤含水量或总氮或有机碳含量，以确保幼苗存活，沿着措施，以防止过度放牧。
Abstract. The endemic argan tree (Argania spinosa) populations in southern Morocco are highly degraded due to overbrowsing, illegal firewood extraction and the expansion of intensive agriculture. Bare areas between the isolated trees increase due to limited regrowth; however, it is unknown if the trees influence the soil of the intertree areas. Hypothetically, spatial differences in soil parameters of the intertree area should result from the translocation of litter or soil particles (by runoff and erosion or wind drift) from canopy-covered areas to the intertree areas. In total, 385 soil samples were taken around the tree from the trunk along the tree drip line (within and outside the tree area) and the intertree area between two trees in four directions (upslope, downslope and in both directions parallel to the slope) up to 50 m distance from the tree. They were analysed for gravimetric soil water content, pH, electrical conductivity, percolation stability, total nitrogen content (TN), content of soil organic carbon (SOC) and C/N ratio. A total of 74 tension disc infiltrometer experiments were performed near the tree drip line, within and outside the tree area, to measure the unsaturated hydraulic conductivity. We found that the tree influence on its surrounding intertree area is limited, with, e.g., SOC and TN content decreasing significantly from tree trunk (4.4 % SOC and 0.3 % TN) to tree drip line (2.0 % SOC and 0.2 % TN). However, intertree areas near the tree drip line (1.3 % SOC and 0.2 % TN) differed significantly from intertree areas between two trees (1.0 % SOC and 0.1 % TN) yet only with a small effect. Trends for spatial patterns could be found in eastern and downslope directions due to wind drift and slope wash. Soil water content was highest in the north due to shade from the midday sun; the influence extended to the intertree areas. The unsaturated hydraulic conductivity also showed significant differences between areas within and outside the tree area near the tree drip line. This was the case on sites under different land usages (silvopastoral and agricultural), slope gradients or tree densities. Although only limited influence of the tree on its intertree area was found, the spatial pattern around the tree suggests that reforestation measures should be aimed around tree shelters in northern or eastern directions with higher soil water content or TN or SOC content to ensure seedling survival, along with measures to prevent overgrazing.