种植年限对设施菜田土壤剖面磷素累积特征的影响

以山东寿光集约化设施菜田为研究对象,分析了不同种植年限设施菜田土壤磷素投入和土壤磷素累积的差异,比较不同种植年限土壤剖面中无机磷、有机磷、Olsen-P和CaCl2-P含量的变化特征。结果表明:磷素过量积累是设施菜田的显著特征,主要由于有机肥以粪肥投入为主,复合肥中P素比例偏高,收获作物带走量仅占磷素投入的7.2%;随着种植年限增加,P素累积现象明显,过量的磷素盈余导致了土壤剖面中不同形态磷含量的上升,其中以无机磷尤其明显;用来表征土壤有效磷指标的Olsen-P与CaCl2-P有显著的相关性,研究区域中当土壤(Olsen-P)达到80.7mg·kg-1时,土壤CaCl2-P开始显著升高,增大了设施菜田磷素淋溶风险。

Effects of Cropping Years on the Characteristics of Phosphorus Accumulation in Soil Profiles Under Greenhouse Vegetable Production

Based on the collective data from field surveys in intensive vegetable greenhouses in Shouguang,Shandong,the study was aimed to investigate the differences of phosphorus(P) input and soil P accumulation in greenhouse production with different cropping years,and compare the variation in the contents of total P(TP),organic P,inorganic P,Olsen-P and CaCl2-P in soil profile.The results showed excessive P accumulation was the typical characteristics in greenhouse field due to the use of animal manure and compound fertilizers with high P content and the removal of very P amount by vegetables,only accounted for 7.2% of total P input.Planting age increased the extent of P accumulation in greenhouse,and P surplus increased the concentrations of soil P in different forms,especially inorganic P,in soil profile.A positive correlation was significantly evident between the contents of Olsen-P,which indicated soil available P supply,and CaCl2-P,which was regarded as the index of P runoff;In the surveyed region soil CaCl2-P level significantly increased while soil Olsen-P content increased up to 80.4 mg·kg-1 in soil,which rapidly accelerated the high risk of P loss to environment.