种植甘草预防土壤风蚀效应

Erosion-resistance effects of Glycyrrhiza vegetation coverage

本研究通过多次测定甘肃酒泉地区甘草地的风蚀量、土壤含水率和地表粗糙度,分析种植甘草（Glycyrrhiza uralensis）防治土壤风蚀的效应。结果表明,随着甘草种植年限的增加,甘草地上生物量呈显著增加趋势,甘草地的地表粗糙度和土壤表层（0-5cm）含水率分别比裸地高12～55倍和27%～148%;种植甘草能显著降低耕地风蚀,甘草地的土壤风蚀量较裸地下降16%～83%。相关分析显示,甘草地上生物量与地表粗糙度、土壤含水率间表现为显著的正相关关系（P〈0.01）,而与土壤风蚀量表现为显著的负相关性。分析认为,种植甘草提高耕地抗风蚀能力主要通过甘草枯枝落叶覆盖地表,造成地表粗糙度和土壤含水率增大,相应地减弱风对地表的吹蚀作用,提高耕地地表砂粒的启动风速,从而最终降低耕地的土壤风蚀。

The present study determined erosion-resistance effects of fields planted with Glycyrrhiza uralensis through measuring soil moisture content, aerodynamic roughness of soil surface and soil loss. The above ground biomass of G. uralensis community significantly increased with the extension of growing years. The aerodynamic roughness of soil surface increased by 12～55 times and soil moisture content in soil surface （0-5 cm） increased by 27%～148% after G. uralensis planted. Soil wind erosion in G. uralensis lands significantly decrease by 16～83% than that of barren land. The above ground biomass positively correlated with roughness length and soil moisture content and negatively correlated with soil erosion. The possible mechanism of wind erosion resistance by planting G. uralensis was that surface of cultivated land was covered by the above ground dry branches and fallen leaves of G. uralensis which increased roughness of soil surface and topsoil moisture content, decreased the wind speed on soil surface and increased the starting wind speed for soil sand grain.