不同土地利用方式下片麻岩坡面养分流失规律的研究

通过室内模拟人工降雨试验，研究不同土地利用方式片麻岩坡面水土流失和养分流失特征。结果表明:谷子地、草地坡面产沙量产流量远小于裸地产沙产流量；不同土地利用方式片麻岩坡面产流产沙变化过程不同，草地、谷子地达到稳定产流的时间滞后于裸地。3种土地利用方式坡面养分流失随时间的变化过程基本相同，降雨起始各种养分浓度较高，随着时间的持续，养分流失浓度趋于稳定。不同土地利用方式下片麻岩坡面养分流失量表现为钾流失总量 > 氮流失总量 > 磷流失总量，养分流失总量与产沙产流之间有着极显著的正相关性，裸地养分流失量最大，其次是谷子地，草地的养分流失量最小，但是径流中硝态氮含量和泥沙总磷量谷子地流失量最大，裸地次之，草地最小。3种土地利用方式片麻岩坡面磷钾流失主要是泥沙态养分，氮素流失主要以溶解态氮为主或者二者共同作用。

Study on the Law of Nutrient Loss of Different Land Use Patterns in Sloping Gneiss Area

Indoor rainfall experiment was conducted to evaluate the effects of land use patterns on the surface soil and nutrient loss in gneiss area. Results showed that runoff and sediment yield of millet land, grassland were far less than those of the bared; the rates of runoff and sediment yields were different among different land uses. Meanwhile, the stable runoff time of millet land and grassland lagged in the bare land. The process of nutrient loss was basically same in the three kinds of land use types: at the beginning nutrient concentration was higher, nutrient concentration tends to be stable over time. The nutrient loss is significantly positively correlated to the cumulative runoff and sediment yield. The amounts of nutrient loss under in the three kinds of land use types represented the cumulative loss oder of potassium > nitrogen > phosphorus. In addition, the nutrient loss of bare land was the largest, followed by millet land and grassland, except nitrate nitrogen concentration in the runoff and the phosphorus concentration in the sediment, of which were the largest in millet land, followed in the bare land. Nutrient losses from gneiss area are mainly in the form of sediment combination state especially for phosphorus and potassium, N loss is mainly in dissolved nitrogen or both dissolved nitrogen and sediment-associated nitrogen.