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| DOI：10.13522/j.cnki.ggps.2019193 |
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| The Effects of Long-term Saline Water Irrigation on Stability of Soil Aggregates in a Cotton Field |
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WU Yuqing, ZHENG Chunlian, SUN Jingsheng, LI Kejiang, DANG Hongkai, ZHANG Junpeng
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1. College of Water Conservancy and Civil Engineering, Shandong Agricultural University, Taian 271018, China;2. Key Laboratory of Crop Drought Resistance Research of Hebei Province/Institute of Dryland Farming, Hebei Academy of Agriculture and Forestry Sciences, Hengshui 053000, China; 3. Key Laboratory for Crop Water Requirement and Regulation of the Ministry of Agriculture and Rural Affairs/Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China
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| Abstract: |
| 【Objective】Saline water is widely distributed in the world and has been used in combination with fresh water to irrigate crops. This paper aims to study the impact of saline water irrigation on stability of soil aggregates in a cotton field.【Method】The field experiment was conducted at a cotton field in north China plain that has been irrigated with saline water for a decade. We compared irrigation with six salt concentrations: 1 g/L (CK), 2 g/L (T1), 4 g/L (T2), 6 g/L (T3), 8 g/L (T4) and 10 g/L (T5). In each treatment, we measured soil salinity in the top 0~30 cm soil layer, content of water-stable aggregates >0.25 mm (R0.25), the mean weight diameter (MWD) and mean geometric diameter (GMD) of the aggregates, as well as their fractal dimension (D).【Result】Soil salinity increased with salt concentration of the irrigation water and decreased with soil depth at early growth stage of the cotton. At the late stage, soil salinity in the subsoil was higher than that in the topsoil and the overall soil salinity was lower than that at the early growth stage. As salt concentration in the irrigation water increased, the content of water-stable aggregates >0.25 mm, MWD and GMD all decreased while D increased. Salt leaching by rainwater and soil consolidation due to root growth combined to enhance soil aggregation, which improved soil quality and led to an increase in numbers of large aggregates, MWD and GMD and a decrease in D, especially in top 10~20 cm soil. 【Conclusion】Irrigating with saline water by keeping the salt concentration lower than 6 g/L did not result in a significant salt accumulation in the topsoil and had less damage to soil aggregates in the cotton field. |
| Key words: saline water irrigation; soil salt; water-stable soil aggregates; stability index |
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