On low-input smallholder farms of Kenyan upland landscapes, erosion of nutrient-rich topsoil strongly affects crop yields. Where maize (Zea mays) is intercropped on erosion-prone slopes, intercropping can potentially reduce soil erosion. The objective of this research was to quantify the contribution of crops and crop mixtures of different growth habits to erosion control and their influence on above-ground biomass and earthworm abundance as indicators of soil function in smallholder farming systems under a bimodal rainfall pattern in Western Kenya. The experiment involved five treatments, namely maize (Z. mays)/common bean (Phaseolus vulgaris) intercrop (maize intercrop), maize/common bean intercrop plus Calliandra (Calliandra calothyrsus) hedgerows and Calliandra mulch (Calliandra), sole Lablab (Lablab purpureus), sole Mucuna (Mucuna pruriens) and groundnut (Arachis hypogaea) intercropped with maize (during the short rains). The experiment was conducted over three consecutive cropping seasons and the cropping system had significant effects on soil loss, runoff, water infiltration, earthworm abundance and above-ground biomass and crop grain yield. The Calliandra treatment had the lowest runoff (11.6–17.2 mm ha−1) and soil erosion (31–446 kg ha−1 per season) in all the seasons, followed by the Mucuna treatment. Lablab was affected by disease and showed the highest soil erosion in the last two seasons. Infiltration was highest in Calliandra treatment, and earthworm abundance was higher under Mucuna and Calliandra treatments (229 and 165 earthworms per square metre, respectively) than under other crops. Our results suggest that including sole crops of herbaceous species such as Mucuna, or tree hedgerows with mixtures of maize and grain legumes has the potential to reduce runoff and soil erosion in smallholder farming. Additionally, these species provide a suitable habitat for earthworms which stabilise soil structure and macropores and thus potentially increase infiltration, further reducing soil erosion.

中文翻译：

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通过引进不同的作物类型减少东非小农耕作系统的土壤侵蚀

在肯尼亚高地景观的低投入小农农场，营养丰富的表土的侵蚀强烈影响作物产量。哪里玉米（玉米) 在易受侵蚀的斜坡上间作，间作可以潜在地减少土壤侵蚀。本研究的目的是量化不同生长习性的作物和作物混合物对侵蚀控制的贡献及其对地上生物量和蚯蚓丰度的影响，作为肯尼亚西部双峰降雨模式下小农农业系统的土壤功能指标. 试验涉及五个处理，即玉米（Z.梅斯)/普通豆子(菜豆) 间作 (maize intercrop), maize/common bean intercrop plus Calliandra (马蹄莲) 树篱和 Calliandra mulch (Calliandra)，唯一的 Lablab (Lablab purpureus), 唯一的 Mucuna (黧豆) 和花生 (花生) 与玉米间作（在短雨期间）。该试验在连续三个种植季节进行，种植制度对土壤流失、径流、水入渗、蚯蚓丰度、地上生物量和作物粮食产量都有显着影响。Calliandra 处理的径流最低（11.6-17.2 mm ha-1) 和土壤侵蚀 (31–446 kg ha-1每个季节）在所有季节，然后是 Mucuna 治疗。Lablab 受到疾病的影响，并在过去两个季节中显示出最高的土壤侵蚀。Calliandra 处理的入渗最高，Mucuna 和 Calliandra 处理的蚯蚓丰度（每平方米分别为 229 和 165 条蚯蚓）高于其他作物。我们的研究结果表明，包括单一的草本作物，如黧豆，或混合玉米和谷物豆类的树篱，有可能减少小农农业的径流和土壤侵蚀。此外，这些物种为蚯蚓提供了合适的栖息地，可以稳定土壤结构和大孔隙，从而潜在地增加渗透，进一步减少土壤侵蚀。