不同坡度下玉米生长期紫色土坡面径流及其

为探明紫色土横垄坡面径流与可溶性有机碳流失对不同坡度的响应特征，通过径流小区和野外人工模拟降雨相结合的方法，探讨了不同坡度条件下玉米各生育期地表径流、壤中流及其可溶性有机碳（DOC）流失特征。结果表明：玉米各生育期同一降雨时间段地表径流量均表现为20° > 15° > 10°，壤中流径流量却表现为10° > 15° > 20°。不同坡度下，玉米生育期地表径流量大小总体表现为苗期 > 成熟期 > 拔节期 > 抽雄期，壤中流量整体表现为抽雄期 > 拔节期 > 苗期 > 成熟期。玉米各生育期地表径流DOC质量浓度均表现为20° > 15° > 10°，不同坡度下玉米生育期地表径流DOC质量浓度表现为苗期 > 拔节期 > 成熟期 > 抽雄期。苗期、拔节期和成熟期壤中流DOC质量浓度大小表现为10° > 15° > 20°，不同坡度下玉米生育期壤中流DOC质量浓度的总体表现为苗期最大，抽雄期最小。玉米各生育期地表径流DOC迁移通量大小均表现为20° > 15° > 10°，不同坡度地表径流DOC迁移通量均表现为苗期 > 成熟期 > 拔节期 > 抽雄期；玉米各生育期壤中流DOC迁移通量大小均表现为10° > 15° > 20°，不同坡度下壤中流DOC迁移通量与地表径流一致。研究结果可为不同坡度条件下玉米生长期坡面径流损失和有机碳流失调控提供理论依据。

Characteristics of Runoff and Dissolved Organic Carbon Loss in Purple Soil with Different Slope Gradients During Maize Growth Stages

In order to investigate the response characteristics of the runoff and organic carbon loss to slope gradients in slope purple soil farmland with contour ridges, the surface runoff, interflow and dissolved organic carbon loss were studied during maize growth stages. Runoff plots and field artificial rainfall simulation methods were adopted. The results showed that the surface runoff displayed an order of 20° > 15° > 10° during the whole maize growth stage, while the interflow for 10° > 15° > 20°. For the different slope gradients, the surface runoff displayed an order of seedling stage > mature stage > jointing stage > tasseling stage, however, the interflow followed:tasseling stage > jointing stage > mature stage > seedling stage. The dissolved organic carbon (DOC) mass concentrations of surface runoff showed 20° > 15° > 10° during the whole maize growth stage, and seedling stage > jointing stage > mature stage > tasseling stage for the different slope gradients. The DOC mass concentrations of interflow showed an order of 10° > 15° > 20° at seedling stage, jointing stage and mature stage. The DOC mass concentration of interflow at seedling stage was maximum and tasseling stage was minimum for the different slope gradients. The DOC migration flux of surface runoff displayed an order of 20° > 15° > 10° during the whole maize growth stage, and seedling stage > mature stage > jointing stage > tasseling stage for the different slope gradients. The DOC migration flux of interflow displayed an order of 10° > 15° > 20° during the whole maize growth stage, while DOC migration flux of interflow for the different slope gradients showed the consistency with surface runoff. These results could provide theoretical basis for runoff and organic carbon loss regulation under different slope gradients during maize growth season.