坡耕地红壤主要农作物根系固土抗蚀生物力学特征研究

The pollution caused by soil erosion from red soil of sloping land has become increasingly serious. Crop management is the most important measure for soil and water conservation in sloping arable land. There were many researches studying above red soil features of vegetation on runoff and soil loss. Besides, effects of crop root features on crop growth and yield were well studied. However, the effects of crop root features on soil erosion in red soil of arable land are rarely investigated. We found that crop root feature do affect soil erosion in previous study. In this study, maize, tobacco, potato ,and soybean as main crops with different root systems in Yunnan Province will be studied by planting (maize//soybean, maize //potatoes )under mono-cropping and intercropping systems. We will deeply study：1. The antierodibility feature of the same crop root will be measured under different growth stages and soil depth; 2. The response of crop root antierodibility to root features will be studied with different crops in different soil depth.3. The impact of intercropping system of red soil crops on root features and soil antierodibility will be measured. The study will reveal the impact of crop root feature on root antierodibility and clear the impact and effect of intercropping system on crops root features and antierodibility. The study will enhance means and methods of red soil conservation in slopping arable land and provide a theoretical basis for allocation of regional water erosion treatment and forecast of soil erosion.

坡耕地红壤水土流失带来的污染日益严峻，农作物是坡耕地水土保持的重要因子。以往的研究多集中在坡耕地红壤系统中作物地上部分通过覆盖作用对坡面径流、冲刷的影响。尽管农作物根系特征的研究较多，但却少有人研究农作物根系对坡耕地红壤侵蚀的影响。项目组前期研究发现，农作物根系特征对坡耕地水土保持确有影响。本研究拟对云南坡耕地红壤主要农作物玉米、烤烟、马铃薯和大豆进行单作和间作（玉米//大豆、玉米//马铃薯）种植，深入研究：（1）相同作物根系在不同生育期和土壤深度上的固土抗蚀性特征；（2）不同作物在不同土壤深度上的固土抗蚀性对根系特征的响应；（3）坡耕地红壤农作物间作对根系特征和固土抗蚀性的影响；揭示农作物根系固土抗蚀性对根系特征的响应机制；明确间作对作物根系特征和固土抗蚀性的影响与作用。通过上述研究可以增强坡耕地红壤水土保持的手段和方法，为区域水土流失防治措施配置及土壤侵蚀预报提供理论依据。

坡耕地红壤水土流失严重，植物根系对水土流失的控制有地上部分和其它措施无法比拟的效果。本研究以云南坡耕地红壤主要农作物玉米、烤烟、马铃薯和大豆进行单作和间作（玉米//大豆、玉米//马铃薯）种植，通过3年的田间小区实验，研究了农作物根系固土抗蚀性对根系特征的响应机制及间作对作物根系特征和固土抗蚀性的影响与作用。.结果表明：（1）间作模式各土层根系指标均大于单作模式，且各根系指标随土层深度增加呈明显的降低趋势。各生育期间作模式下根系特征指标都优于单作，且其差异性随生育期变化不断增大。在生育初期，玉米//马铃薯间作的根系特征指标均优于玉米//大豆间作，随生育期推进，则情况相反。（2）间作模式下各团聚体稳定性指标均优于单作模式，其中以玉米//大豆间作模式表现最为明显，0～10cm土层，玉米//大豆间作＞0.25mm团聚体的数量较大豆单作、玉米单作分别增加了29.58%、66.01%。各种植模式的团聚体破坏率均随着土层的增加而增加，土壤抗蚀性指数相反。（3）间作处理下，农作物的固持土壤能力要强于单作处理的农作物。各种植模式下农作物固土能力均随土层深度的增加而降低，且以间作模式的降低程度较高。0-10cm层，玉米//马铃薯间作根系固土能力强于玉米//大豆间作，随着土层深度的增加，情况相反。（4）间作模式下根系特征分别与团聚体破坏率、土壤流失量呈显著的负相关关系（P<0.05或P<0.01），而与固土力则呈显著的正相关关系（P<0.05或P<0.01），且明显高于单作模式，其中以含根量和根表面积与固土力相关性最高，相关系数达0.51～0.91。成熟期土壤流失总量中，玉米//马铃薯间作较马铃薯单作、玉米单作分别减少49.67%，40.31%，玉米//大豆间作较大豆单作、玉米单作分别显著降低了58.47%和62.01%。.该研究对揭示农作物根系固土抗蚀性对根系特征的响应机制及间作对作物根系特征和固土抗蚀性的影响具有重要作用。这为区域水土流失防治措施配置及土壤侵蚀预报提供理论依据，指导农作物种类和种植模式的合理配置以达到坡耕地红壤的可持续利用。