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| DOI：10.13522/j.cnki.ggps.2025182 |
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| Difference in soil water and salt dynamics between irrigated and rainfed grasslands |
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LI Ziang, JIN Xin, JIN Yanxiang
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1. Qinghai Province Key Laboratory of Physical Geography and Environmental Process, College of Geographical Science,
Qinghai Normal University, Xining 810016, China; 2. Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation (Ministry of Education), Qinghai Normal University, Xining 810016, China; 3. Academy of Plateau Science and Sustainability, People’s Government of Qinghai Province and Beijing Normal University, Xining 810016, China
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| Abstract: |
| 【Objective】Alpine arid regions are characterized by scarce precipitation and fragile ecosystems, where soil water-salt dynamics directly affect grassland productivity and ecological stability. While irrigation is critical to maintaining grassland sustainability in these regions, it also alters the natural pattern of soil water-salt transport. Understanding changes in soil water-salt transport due to irrigation is important for improving water resource management and grassland ecological protection. This paper presents the results of an experimental study on differences in soil water-salt transport between rain-fed and irrigated grasslands.【Method】The study was based on spatiotemporal change in soil water and salt measured continuously during the 2024 growing season in a typical rain-fed and an irrigated grassland in the northeastern Qaidam Basin. Combined with mutation tests and correlation analysis, the differences in spatiotemporal dynamics of soil water and salt and their responses to precipitation events in the two grasslands were analysed.【Result】①The average soil saturation in the rain-fed grassland was 50.87%, which was mainly regulated by precipitation, and that of the irrigated grassland was 91.89%. ②The average soil salinity in the 10-50 cm soil layer was 77.18 mg/kg in the irrigated grassland and 91.03 mg/kg in the rain-fed grassland. The temporal dynamics of soil salinity during the experimental period in both grasslands could be divided into four stages: leaching, stabilization, salt accumulation, and secondary leaching. ③Irrigation attenuated the effect of precipitation on soil water content and salinity. ④Salt leaching was transient. On average over the experimental period, salt leaching efficiency of the precipitation in the rain-fed grassland was 0.9 mg/(kg·mm), significantly higher than that of 0.5 mg/(kg·mm) in the irrigated grassland. 【Conclusion】Irrigation alters soil water-salt transport pattern in the alpine arid grasslands, which not only reduces salt accumulation but also dampens the regulatory effect of precipitation in soil salinity. These results can help develop ecological protection and improve water management of the grasslands in alpine arid regions. |
| Key words: soil water-salt; precipitation; irrigation; Qaidam Basin; grassland ecosystem |
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