人工模拟降雨不同施肥方式下紫色土养分流失研究

Study of Nutrient Loss in Purple Soil in Artificially Simulated Rainfall Conditions under Different Fertilization Modes

试验采用人工模拟降雨装置,研究了紫色土在表施肥和混施肥两种施肥方式下磷、钾养分径流流失规律.结果表明,两种施肥方式径流中养分浓度均随时间呈幂函数下降,但表施肥径流中磷钾养分含量明显高于混施肥,且在降雨产流初期表现尤为明显;在养分流失量方面,两种施肥方式径流中可溶性P及速效K累积流失量均随时间呈近似直线增加,表施肥明显大于混施肥,但混施肥养分流失50%～70%在开始降雨产流的前10 min内发生,而表施肥养分流失贯穿整个产流过程.同时试验发现施肥方式对坡面产流无显著影响.

An artificially simulated rainfall device was used to study the loss of N and P in the runoff under surface fertilization and mixed fertilization in the purple soil.The results showed that nutrient concentration in the runoff under both fertilization modes decreased with time,and their relationships could be represented by a power function equation,but N and P nutrient content in runoff under surface fertilization was significantly higher than that under mixed fertilization,particularly in the early stage of the formation of rainfall runoff.In addition,accumulation of soluble P and available K in the runoff showed an approximately linear increase with the time under both fertilization modes,being significantly higher under surface fertilization than under mixed fertilization.However,50～70% of nutrient loss occurred within the first 10 min of rainfall runoff under mixed fertilization,but it occurred throughout the entire process under surface fertilization.The experiment also found that fertilization modes had no significant effect on slope surface runoff.