【摘要】 采用负压式土壤溶液取样器采集不同施肥水平（常规、减量20%和减量30%施肥处理,即N1、N2和N3）下城郊菜地耕层土壤（10、20和30 cm）的淋溶液,分析了总氮（TN）、硝态氮（NO₃^-）、铵态氮（NH₄⁺）、总磷（TP）和溶解态磷（DP）浓度,旨在研究不同施肥水平下菜地不同耕层土壤中氮素与磷素的淋溶损失特征。研究结果:（1）不同施肥水平下,菜地耕层土壤TN、NO₃^-、NH₄⁺、TP和DP淋溶质量浓度范围分别为5.24²92、3.47²71、0.16⁹.47、1.66²0.6和1.63¹7.7mg·L^-1,平均质量浓度分别为38.9¹13、36.0¹05、1.01².13、3.75¹2.7和3.55¹1.8 mg·L^-1;（2）氮素主要以NO3-形式发生淋溶损失,作物生长初期是菜地耕层土壤氮素淋溶损失的主要时期;减量施肥30%能有效降低耕层土壤氮素的淋溶损失,其TN和NO₃^-的淋溶质量浓度较常规施肥处理分别显著降低了58.4%和59.0%（P<0.05）;不同深度耕层土壤中TN和NO3-淋溶质量浓度没有显著性差异（P>0.05）;（3）磷素主要以DP形式发生淋溶损失,耕层土壤中TP和DP的淋溶质量浓度为20 cm>10 cm>30 cm（P<0.05）;减量20%和减量30%施肥均能有效降低耕层土壤中磷素的淋溶损失,减量20%施肥处理TP和DP的淋溶质量浓度分别显著下降了27.8%和27.6%（P<0.05）,而减量20%施肥处理TP和DP的淋溶质量浓度分别显著降低了44.6%和43.8%（P<0.05）。结果表明,城郊菜地耕层土壤中氮素和磷素养分存在一定的淋失风险,减量施肥措施能有效降低菜地耕层土壤中氮素与磷素的淋溶损失,是降低耕层土壤氮磷淋失风险的有效措施。更多还原

【Abstract】 In the present study,soil leachates were collected with negative-pressure soil solution samplers from vegetable soils（i.e.,10,20 and 30 cm） under three fertilization levels（i.e.,regular,20% and 30% reduction fertilization treatments for N1,N2 and N3,respectively）.Mass concentrations of total nitrogen（TN）,nitrate nitrogen（NO₃^-）,ammonium nitrogen（NH₄⁺）,total phosphorus（TP） and dissolved phosphorus（DP） were determined to study the leaching characteristics of nitrogen and phosphorus in vegetable surface soils under different fertilization levels.The results showed that:（1） the leaching mass concentrations of TN,NO₃^-,NH₄⁺,TP and DP varied in 5.24²92,3.47²71,0.16⁹.47,1.66²0.6 and 1.63¹7.7 mg·L^-1,respectively,with the avarage ranges of 38.9¹13,36.0¹05,1.01².13,3.75¹2.7 and 3.55¹1.8 mg·L^-1.（2） Nitrogen was mainly lost in the form of NO₃^-with the pre-stage of vegetable growth period as a pivotal time for leaching loss.In comparison to N1,N3 could effectively reduce the leaching loss of nitrogen,where TN and NO₃^-levels were significantly reduced by 58.4% and 59.0%,respectively（P<0.05）.There was no significant difference in the leaching levels of TN and NO₃^-among 10,20 and 30 cm（P>0.05）.（3） Phosphorus was largely leached in the form of DP,where the leaching mass concentrations of TP and DP were 20 cm > 10 cm > 30 cm（P<0.05）.Comparing with N1,the leaching levels of TP and DP were decreased by 27.8% and 27.6% for N2（P<0.05）,while they were reduced by 44.6% and 48.0% for N3（P<0.05）.The results indicated that nitrogen and phosphorus in the suburban vegetable soils had certain leaching risks.Reducing fertilizer application can decrease the leaching mass concentrations of TN and TP,which is suggested to be an effective measure to reduce the leaching risk of TN and TP in vegetable surface soils.更多还原