埃塞俄比亚西南部坡地的水土保持管理。一. 土埂对地表径流、侵蚀和养分流失的影响。
Soil and water conservation management on hill slopes in Southwest Ethiopia. I. Effects of soil bunds on surface runoff, erosion and loss of nutrients.
机构信息
Norwegian University of Life Science, Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, No1432, Aas, Norway; Hawassa University, Wondo Genet College of Forestry and Natural Resource, P.O. Box 128, Shashemene, Ethiopia.
Hawassa University, Wondo Genet College of Forestry and Natural Resource, P.O. Box 128, Shashemene, Ethiopia; International Crop Research Institute for Semi-Arid Tropics, P.O. Box 5689, Addis Ababa, Ethiopia.
出版信息
Sci Total Environ. 2021 Feb 25;757:142877. doi: 10.1016/j.scitotenv.2020.142877. Epub 2020 Oct 9.
On the steep hill slopes of southwest Ethiopia, soil erosion may cause significant declines in soil organic carbon (SOC) and nutrients, negatively affecting cropland productivity. Soil bunds are advised as an effective means to reduce surface runoff and soil erosion. However, the effects on SOC and nutrients are rarely quantified. The objective of this study was to assess the quantitative effect of soil bunds on surface runoff as well as soil and nutrients losses from cropland in the region. Data was collected from experimental fields on three farms (fields 1, 2 and 3) in the Omo-Gibe River basin in southwest Ethiopia. On each farm, effects of soil bunds on runoff and erosion were investigated and compared with adjacent plots without soil bunds in the 2018 and 2019 growing seasons. Soil bunds effectively reduced surface runoff (by 80-92%). Without soil bunds, soil losses in the growing season were 5-22 t ha in 2018 and 15-43 t ha in 2019, on average removing 1.3-4 mm soil per year. Soil bunds decreased soil losses by about 96%. Observed soil losses from fields without soil bunds were well described by the Universal Soil Loss Equation (USLE; R = 0.92; p < 0.01). Of the total soil loss, 47-69% was removed in suspended form. Suspended material had significantly larger (p < 0.05) SOC, and plant available potassium (K) and phosphorus (P) concentrations than coarser, rapidly settling sediment and bulk soil. In 2019, up to 733 kg SOC ha, 77 kg total nitrogen ha and 21 kg K ha were lost per season from plots without soil bunds. For SOC this amounts to 6% of its stocks in the topsoil. Soil bunds are important controls on surface runoff, strongly limiting losses of SOC and nutrients in sloping croplands of southwest Ethiopia.
在埃塞俄比亚西南部的陡坡上，土壤侵蚀可能导致土壤有机碳（SOC）和养分大量减少，从而对农田生产力产生负面影响。土壤垄被建议作为减少地表径流和土壤侵蚀的有效手段。然而，SOC 和养分的影响很少被量化。本研究的目的是评估土壤垄对该地区农田地表径流以及土壤和养分流失的定量影响。数据来自埃塞俄比亚奥莫-吉贝河流域三个农场（1 号、2 号和 3 号）的实验田。在每个农场，都在 2018 年和 2019 年的生长季节，调查了土壤垄对径流和侵蚀的影响，并与相邻无垄的地块进行了比较。土壤垄有效地减少了地表径流（80-92%）。在没有土壤垄的情况下，2018 年生长季土壤流失量为 5-22 吨/公顷，2019 年为 15-43 吨/公顷，平均每年流失 1.3-4 毫米土壤。土壤垄减少了约 96%的土壤流失。没有土壤垄的农田的观测土壤流失量很好地符合通用土壤流失方程（USLE；R=0.92；p<0.01）。总土壤流失量中，47-69%以悬浮形式被去除。悬浮物质的 SOC、植物有效钾（K）和磷（P）浓度明显大于较粗、快速沉降的沉积物和原状土。在 2019 年，每个生长季，没有土壤垄的地块中 SOC 流失了 733 公斤/公顷，总氮流失了 77 公斤/公顷，K 流失了 21 公斤/公顷。对于 SOC 来说，这相当于表土中 SOC 储量的 6%。土壤垄是地表径流的重要控制因素，强烈限制了埃塞俄比亚西南部坡耕地中 SOC 和养分的流失。
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