Influences of soil, terrain, and crop growth on soil moisture variation from transect to farm scales
Influences of soil, terrain, and crop growth on soil moisture variation from transect to farm scales
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DOI：
10.1016/j.geoderma.2011.03.015
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发表时间：
2011-06
期刊：
影响因子：
6.1
通讯作者：
Q. Zhu;Henry Lin
中科院分区：
文献类型：
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作者：
Q. Zhu;Henry Lin
土壤和地形被广泛认为是土壤湿度变化的重要控制因素。土壤湿度在景观中的分布通常被定义为在干旱期主要由土壤性质控制，在潮湿期主要由地形控制。然而，这种概念化没有明确考虑植物生长、空间尺度和土壤深度。在4个空间尺度（整个农田19.5 ha、地貌单元0.3 ~ 5.1 ha、地块面积10 × 10 m、坡样面积40 × 2 m）、3个深度（0.1、0.4和0.8 m）和2个季节（作物生长期和非生长期）下，研究了土壤、地形和作物对农业景观土壤水分变化的影响。结果表明：在一定的空间尺度上，对土壤水分变异的控制因季节、土壤深度和土壤地形变异程度而异。在生长季节，作物和土壤对土壤水分的影响显著，特别是在0.1和0.4 m深度；而在非生长期，地形属性对土壤水分变化的影响更为显著，特别是0.8 m深度，土壤普遍较湿润。在坡度较陡的地区（坡度< 8%），地形对土壤性质的控制对土壤水分的变化起主导作用，而在坡度< 8%的相对平坦地区（坡度< 8%），无论季节和土壤湿度如何，土壤性质都起主导作用。总体而言，地形对土壤水分的影响随地形变化而增加（本研究中坡度百分比）。在土壤性质变化较大的山坡上，土壤对水分变化的影响较为明显，而在土壤性质相对均匀的样带上则不明显。总体而言，本研究揭示了典型农业景观中地形、土壤和作物对土壤水分控制的空间复杂性和时间动态交织在一起，其程度是空间尺度、土壤深度和季节的函数。
Soil and topography are widely recognized as important controls of soil moisture variation. Soil moisture distribution in a landscape has often been conceptualized as being controlled predominantly by soil properties during dry periods, and by topography during wet periods. However, this conceptualization does not explicitly consider plant growth, spatial scale, and soil depth. We investigated the influences of soil, terrain, and crop on soil moisture variation in an agricultural landscape at four spatial scales (entire farm of 19.5 ha, landform unit of 0.3–5.1 ha, plot size of 10 × 10 m, and slope transect of 40 × 2 m), in three depths (0.1, 0.4, and 0.8 m), and during two seasons (crop growing vs. non-growing seasons). The results showed that the controls on soil moisture variability varied by season, soil depth, and the degree of soil-topography variability at a given spatial scale. During the growing season, crop and soil exerted significant influences on soil moisture, especially at the 0.1- and 0.4-m depth; whereas during the non-growing season, terrain attributes showed more significant impacts on soil moisture variation, particularly at the 0.8-m depth where soils were generally wetter. In areas of steeper slope (> 8%), topography dominated over soil properties in controlling soil moisture variation, while in relatively flat areas (< 8% slope), soil properties dominated regardless of season and soil wetness. Generally, topographic influence on soil moisture increased with topographic variation (slope percent in this study). In hillslope with a greater variation in soil properties, soil's influence on moisture variation was apparent, but not in transects with relative homogenous soil properties. Overall, this study demonstrated the intertwined spatial complexity and temporal dynamics in soil moisture controls by terrain, soil, and crop across a typical agricultural landscape, the degree of which is a function of spatial scale, soil depth, and season.