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首页> 外文期刊>Catena: An Interdisciplinary Journal of Soil Science Hydrology-Geomorphology Focusing on Geoecology and Landscape Evolution >Assessment of soil erosion indicators for maize-based agro-ecosystems in Kenya.
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Assessment of soil erosion indicators for maize-based agro-ecosystems in Kenya.

机译：肯尼亚基于玉米的农业生态系统水土流失指标评估。

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摘要

Measuring soil loss is costly, must cover a range of field situations, is not standardized, and is season dependent. In addition, use of sparse soil loss data (from other studies) compromises the integrity of many erosion models. Easily assessable soil erosion indicators to monitor the cumulative effect of erosion between tillage/weeding and harvesting called eroding clods, flow surfaces, pre-rills, and rills were surveyed directly after the 1995 rainy season in the Taita Taveta district of Kenya, to assessed the utility of each indicator. Their incidences were modelled using CPA. In the area, 70 maize plots in 11 map units, having considerable variation in altitude, land cover, rainfall, and geomorphology, were surveyed. Soil loss was considered variable between plots due to differences in surface soil, land cover, infrastructure (trash lines, grass strips, and Fanya-juu), crop management, slope, and map unit. The eroding clods indicator proved of little significance because the initial clods cover was unknown; the indicator probably relates better to soil erodibility then to soil loss. Flow surfaces, formed during erosive showers, were less present on fields with a higher ground and canopy cover, if the area of eroding clods was high, and if the topsoil had no loam which reduces chances of sealing; no impact of infrastructure, tillage, and weeding were detected. Fewer pre-rills were present where the fraction of groundcover was high, where Pigeon Peas were not grown (they cause micro-relief and concentrated flows), where weeding ended late (time effect), where more flow surfaces occurred, where Fanya-juu was constructed (less steep slopes), where the top-soil contained little sand (less sediment entrainment), and where maize was intercropped with vegetables (positive canopy cover effects). The model was not map unit specific and had an Adjusted R2 of 67%. The log-linear relationship indicates that combined positive conditions exponentially reduce the occurrence of pre-rills. The "pre-rill" indicator related best to management-affected site conditions and seems to reflect best the cumulative effects of soil loss over time. Rills were found at 18 sites located in drier areas on sandy-clay soils. The model suggested more rills if the topsoil contains no si this makes the soil susceptible to compaction, peptisation when wet, and rill formation..
机译：测量土壤流失成本高昂，必须涵盖一系列现场情况，没有标准化，并且取决于季节。此外，使用稀疏的土壤流失数据（来自其他研究）会损害许多侵蚀模型的完整性。 1995年雨季过后，在肯尼亚的Taita Taveta地区直接调查了易于评估的土壤侵蚀指标，以监测耕作/除草与收割之间侵蚀的累积效应，即侵蚀的土块，水面，小溪和小溪，以评估每个指标的效用。他们的发生率使用CPA进行建模。在该地区，以11个地图单元为单位，对70个玉米地进行了调查，高度，土地覆盖率，降雨量和地貌都有很大的变化。由于地表土壤，土地覆盖，基础设施（垃圾线，草条和Fanya-juu），作物管理，坡度和地图单位的差异，土壤流失被认为在各地块之间是可变的。由于最初的血块覆盖物是未知的，因此侵蚀的血块指示剂被证明意义不大。该指标可能与土壤侵蚀性更好，然后与土壤流失有关。如果侵蚀土块的面积很大，并且表层土没有肥沃，减少了密封的机会，那么在侵蚀性阵雨期间形成的水流面在地面和树冠覆盖较高的田地中的存在较少。没有发现基础设施，耕作和除草的影响。在地被植物比例高，没有种鸽豌豆（造成微浮雕和集中水流），除草较晚结束（时间效应），流水面较多，Fanya-juu的地方，较少的预演建造（坡度较小），表层土壤中的沙很少（夹带的泥沙较少），而玉米与蔬菜间作（正冠层覆盖效应）。该模型不是特定于地图单位的，调整后的R2为67％。对数线性关系表明，组合的积极条件成倍减少了预演的发生。 “预钻探”指标与受管理影响的现场条件最相关，并且似乎最能反映土壤流失随时间的累积影响。在沙质土壤较干燥地区的18个地点发现了ill。如果表层土不包含淤泥，该模型建议增加小溪。这使土壤易于压实，潮湿时胶溶和形成小孔。

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