雨强和土地利用对豫西南山区氮磷流失的影响

Effects of rainfall intensity and land use mode on loss of TN and TP in southwest hilly area of Henan Province

为了掌握雨强和土地利用方式对丹江口水库水源区养分流失的影响,通过室内人工模拟降雨试验,对从豫西南山区采集的5种常见土地利用类型的表层土壤,开展了6种雨强下TN(总氮)、TP(总磷)的流失规律研究。结果表明:1地表产流中,雨强对TN的平均含量影响显著,雨强大于1.0 mm/min时才会对TP的含量产生影响;不同用地产生的泥沙中,雨强大于等于3.0 mm/min时才会对TN、TP的含量产生显著影响。2土地类型对TN、TP的流失量也有极大的影响,乔木林、灌草地因其具有较坡耕地、梯田与荒草地更好的土壤结构,TN、TP的流失量相对较少,但前两者之间与后三者之间的差异不大。3对径流中TN、TP的含量与雨强作回归分析,除乔木林地和灌草地略有不同外,其他各用地类均为对数拟合的效果最差,多项式拟合的决定系数较高;不同用地产沙中TN、TP含量与雨强的关系,均以多项式拟合的效果为最好。

To master the effects of rainfall intensity and land use mode on soil nutrient loss in Danjiangkou Reservoir catchment,five common land types of topsoil were collected and the rainfall experiments were conducted to study the rule of TN and TP loss under six rainfall intensity.The results showed that the rainfall intensity influenced the average contents of TN,which would affect TP when it surpassed 1.0 mm/min; for different land use modes,the content of TN and TP would be significantly influenced when the rainfall intensity was equal to or larger than 3.0 mm/min.The land use mode influenced the loss of TN and TP in runoff and sediment.With better soil structure,the loss in arbor woodland and shrubby grassland were less than that in slope cropland,terrace and waste grassland,but the difference is slight.For regression analysis of the content of TN and TP to rainfall intensity,the polynomial equation fitting was the best and the logarithmic fitting was the worst for all the land use types except the arbor woodland and shrubby grassland.The relationship of TN and TP content in sediment yield with rainfall intensity shows that the polynomial fitting results were best.