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| DOI：10.13522/j.cnki.ggps. 20190152 |
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| Spatial distribution of sodic salt in soil affects water infiltration |
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HAN Xiao, ZHANG Ying, ZHAO Junhan, HUANG Rui, WANG Hongde, SHE Dongli
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1. College of Agricultural Engineering, Hohai University, Nanjing 210098, China;2. Jiangning Water Resources Bureau of Jiangsu Province, Nanjing 210098, China
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| Abstract: |
| 【Objective】Soil salinity and sodicity is a ubiquitous abiotic stress affecting agricultural production worldwide. Understanding how sodic salt content modulates water flow in soil can help improve soil management. The objective of this paper is to elucidate the effects of sodic salt content and its spatial distribution on water infiltration.【Method】The experiment compromised six treatments, with the sodic salt distributing either homogenously or heterogeneously in the soil profile. In each treatment, we measured water infiltration using the constant-head method and then compared the infiltration rate, cumulative infiltration and advance of the wetting front between the treatments.【Result】When sodic salt distribution was homogenous, water infiltration rate was related to soil salinity at significant level and the cumulative infiltration decreased with soil salinity, while when the sodic salt was heterogeneous, water movement in the soil was more complicated. Water infiltrated faster when salt content decreased downwards along the soil profile than when salt content decreased upwards. When overall salt content was the same, heterogeneous salt distribution affected cumulative water infiltration more significantly than homogenous salt distribution. The advance of the wetting front in the soil increased with infiltration time, but the infiltration rate decreased asymptotically to a constant as time elapsed. Salt in the top soil affected the advance of the wetting more than salt in the subsoil. 【Conclusion】Our experimental results revealed that water infiltration in saline soil was affected not only by soil salinity but also by how the salt was distributed in the soil profile. Water movement is more intriguing when salt distribution was heterogenous than when it was homogenous. |
| Key words: soil moisture; soil salinity; water infiltration; cumulative infiltration |
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