School of Public Administration, Zhejiang University of Finance and Economics, Hangzhou, 310018, China.
Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
Environ Sci Pollut Res Int. 2020 Apr;27(12):12866-12873. doi: 10.1007/s11356-018-04067-0. Epub 2019 Feb 18.
Soil erosion induced by rainfall has become one of the major environmental disasters. It can lead to degradation of land productivity and water pollution, which limit human survival and development. Therefore, understanding the effects of rainfall intensities on soil nutrient and sediment transportation from farmland via surface runoff is important. This study simulated three types of rainfall intensities (low intensity 0.83 mm min; medium intensity 1.17 mm min and 1.67 mm min; and high intensity 2.50 mm min). Field plots were established to evaluate the effects of rainfall intensities on sediment yield and phosphorus enrichment ratio (ER) in runoff sediment. Each plot was 2 m long and 1 m wide. The rainfall lasted for 30 min after effective runoff generation. Runoff and sediment, as well as the phosphorus (P) concentration of sediment, were measured. Results showed that the low rainfall intensity had a longer time to begin runoff than high rainfall intensity. The runoff volume increased with the rainfall intensity; however, no obvious differences were observed in the runoff rate under three rainfall intensities, except for 2.50 mm min. The curve value of sediment concentration increased after 5-10 min of effective runoff decreased slightly, and then relatively became stable after 20 min of effective runoff. Although no obvious differences were observed in the dynamic changes of sediment concentration and rainfall intensity, a power function existed between rainfall intensity and sediment loss. The similar curves of ER value showed that it was higher in the initial stage, decreased gradually, and reached a stable level after 25 min of effective runoff, which varied around 1. During the rainfall-runoff event, no significant correlation was noted between ER and sediment yield. Whether any relationship existed between them needs to be further studied by setting up different field plots under large-scale conditions. The findings of this study provide valuable aid to farmers on how to manage farmland effectively to prevent soil nutrient loss and reduce water eutrophication.
降雨引起的土壤侵蚀已成为主要的环境灾害之一。它会导致土地生产力退化和水污染，从而限制了人类的生存和发展。因此，了解降雨强度对农田地表径流中土壤养分和泥沙输移的影响非常重要。本研究模拟了三种降雨强度（低强度 0.83mm min；中强度 1.17mm min 和 1.67mm min；高强度 2.50mm min）。建立了野外试验区来评估降雨强度对径流产沙和泥沙中磷素富集比（ER）的影响。每个试验区长 2m，宽 1m。有效产流后降雨持续 30min。测量了径流量和泥沙量，以及泥沙中磷素浓度。结果表明，低降雨强度的产流时间比高降雨强度长。径流量随降雨强度增加而增加；但在三种降雨强度下，除 2.50mm min 外，径流率无明显差异。有效产流后 5-10min 泥沙浓度曲线值略有下降，然后在 20min 左右达到稳定。虽然泥沙浓度和降雨强度的动态变化没有明显差异，但降雨强度与泥沙流失之间存在幂函数关系。ER 值的相似曲线表明，它在初始阶段较高，逐渐降低，在有效产流 25min 后达到稳定水平，约为 1。在降雨-径流事件中，ER 与泥沙产率之间没有显著相关性。它们之间是否存在关系需要在大尺度条件下通过设置不同的野外试验区进一步研究。本研究结果为农民如何有效管理农田以防止土壤养分流失和减少水体富营养化提供了有价值的帮助。
