广西岩溶区稻田土壤优先路径的空间分布

田间土壤优先路径空间分布影响优先流的发生和运动。通过野外土壤染色示踪试验,利用形态学图像解析技术,并结合群落生态学分析方法,对广西岩溶区秸秆覆盖(CM)和非覆盖(CK)下的水稻田进行土壤优先路径空间分布研究。结果表明: 在相同的外部供水状况下,随土壤深度的增加,秸秆覆盖水稻田的土壤水平染色由整体分布向团块状聚集分布转变;非秸秆覆盖水稻田以枝状染色为主,其平均染色斑块形状系数为21.69,染色形态规则,是秸秆覆盖水稻田的1.04倍。秸秆覆盖与非覆盖水稻田的土壤优先路径均呈聚集分布,秸秆覆盖水稻田内优先路径的Morisita指数为1.28,且田间优先路径以影响半径＜1.0 mm为主(重要值0.31),非秸秆覆盖水稻田内影响半径＜1.0 mm的优先路径重要值为0.28。秸秆覆盖影响稻田土壤优先路径,有助于改善田间作物的水肥利用状况。

Spatial distribution of preferential flow paths in paddy field in the Karst Area of Guangxi.

The spatial distribution of the preferential flow path in soil affects the occurrence and movement of preferential flow. In afield soil staining and tracing experiment, with the help of morphological image analysis technology and community ecological analysis method, we examined the spatial distribution characteristics of preferential flow path in paddy fields under straw mulching (CM) and non-mulching (CK) in karst areas of Guangxi. The results showed that, under the same external water supply conditions, with the increases of soil depth, soil horizontal dyeing changed from overall distribution to clump aggregation distribution in paddy field under straw mulching. In the non-mulching paddy field, the main dyeing was branch, with an average shape coefficient of staining patch of 21.69. The dyeing morphology in the non-mulching paddy field was 1.04 times of straw mulching paddy field. The preferential flow paths of straw mulching and non-mulching paddy fields showed both clustered distribution. In straw mulching paddy field, the Morisita index was 1.28 as the preferential flow paths with radius of influence less than 1.0 mm were the main ones (importance value 0.31). The importance value of preferential flow paths with radius less than 1.0 mm was 0.28 in non-straw mulched rice field. Straw mulching affected the preferential flow paths in paddy fields, which could help to improve water and fertilizer utilization of crops in the field.