水肥管理及秸秆还田对设施菜田土壤钾素淋洗的影响

Effect of Irrigation,Fertilization and Straw Incorporation on Soil Potassium Leaching in Vegetable Greenhouse

针对设施蔬菜传统水肥管理模式中钾素过量投入、因缺镁造成果类蔬菜品质下降等问题，以一年两季设施番茄为研究对象，通过对不同土壤深度钾素淋洗的周年动态监测，研究了不同水肥管理模式及秸秆还田对设施菜田土壤钾素淋洗的影响。结果表明，滴灌施肥处理下菜田平均每季钾素盈余394 kg/hm2，明显低于漫灌施肥处理；滴灌施肥菜田0~60 cm土层土壤速效钾累积程度小于漫灌施肥，且显著降低了钾素淋洗量，50，90 cm 处平均每季淋洗量分别为15.9，4.2 kg/hm2，而漫灌施肥体系则分别达到26.9，16.9 kg/hm2，漫灌体系过量灌溉和施肥是导致钾素大量淋洗的根本原因；漫灌体系下添加秸秆后有降低表层土壤速效钾积累的趋势，增加了土壤钾素淋洗。

Excessive inputs of water and fertilizers under conventional greenhouse vegetable production have re-sulted in waste of potassium（ K）resource and decrease of fruit quality. A field experiment was conducted in a greenhouse tomato double-cropping system to monitor the annual leaching dynamic of K in different soil depth and investigate the effects of management modes of water and fertilizer,and straw incorporation on K leaching. Results showed that K surplus was 394 kg/ha per season in fertigation treatment,which was much lower than that in conven-tional management（ application of fertilizer with flooding irrigation）. Compared to conventional management,fertiga-tion decreased the accumulation of available K in the 0 -60 cm soil layer and the leaching of K. Mean seasonal K leaching were 15. 9,4. 2 kg/ha under fertigation system,while that were 26. 9,16. 9 kg/ha under conventional man-agement system in 50,90 cm soil depth,respectively. Excessive inputs of water and fertilizers in conventional manage-ment system significantly contribute to the leaching of K. Straw incorporation decreased the content of soil available potassium in surface soil and increased the leaching of K in conventional management system.