翻耕与压实对坡地土壤溶质迁移过程的影响

Influence of tillage and compaction on solute transport process on the sloping land

采用田间模拟降雨试验方法,研究地表翻耕与压实处理对坡地产流产沙及溶质迁移特征的影响。结果表明:与压实处理比较,翻耕坡地初始产流时间延长近3倍,降雨向土壤水转化率提高10%以上,产沙量增加67%;翻耕处理明显降低溶解态磷(DP)和泥沙浸提态磷(SEP)的流失量,但磷素流失形态(DP与SEP的比值)并未显著变化,始终以颗粒态形式流失为主;翻耕处理显著改变了溴的流失形态,溶解态溴(Br)与泥沙浸提态溴(SBr)流失量比值减少了72%;翻耕处理提高了溴(或硝态氮)的淋失概率,增大污染地下水体的潜在危险。因此,合理配置坡地免耕或翻耕措施,有机结合其他农艺耕作措施,对减少坡地水土及养分流失具有重要实践意义。

Soil and water losses and leaching loss of nutrients from sloping land are major reasons for soil degradation and water pollution. Experiments were conducted on runoff and sediment yield characteristics and nutrients solution movement in field plots by soil surface treatments （tillage and compaction） under simulated rainfall conditions. Comparing soil tillage with the compaction, the initial runoff generation time was delayed by 3 times, the transforming ratio from rainfall to soil moisture was more than 10%, but soil loss amount increased by 67%. Under tillage conditions, the amount of losses of dissolved phosphorus （DP） and sediment extractive phosphorus （SEP） decreased significantly, but the loss form was not changed and particle phosphorus loss was dominant. Tillage treatment had greatly changed the ratio of dissolved bromine （Br） and sediment extractive bromine （SBr）, its value （Br/SBr） reduced by 72 %. Soil tillage enhanced the possibility of bromine （or NO3- -N） leaching. It is practical meaning for decreasing soil, water and nutrients losses from sloping land through taking no-tillage or conservation tillage measures on sloping land, and combining with other cultivated measures.