化肥用量和有机无机复混肥对浙江海涂区氮磷损失的影响

Effects of Amount of Chemical and Organic-Inorganic Compound Fertilizer on N &P Loss in Coastal Saline Region,Zhejiang Province

通过田间小区试验研究了化肥不同施用量和有机无机复混肥对海涂区西兰花种植时氮磷损失的影响,结果表明:①海涂区地表径流中氮以硝态氮为主,前期氮流失量大于后期流失量,前期径流水中水溶性磷和颗粒性磷流失量相近,后期则以颗粒性磷为主;②全化肥增量20%处理径流水中全氮、全磷流失量均高于全化肥处理和全化肥减量20%处理,全化肥处理和全化肥减量20%处理间全氮和全磷流失量差异不显著。有机无机复混肥比等养分投入的全化肥处理增加了径流水中全氮和全磷的流失量;③各处理地下水中硝态氮浓度均较高,全化肥增量20%和有机无机复混肥处理地下水中硝态氮含量高于其余处理,土壤对硝态氮的截留能力较弱,施肥后5天时0.5m深度和1.0m深度硝态氮含量无显著差异。

The effects of application amount of chemical fertilizer and organic-inorganic compound fertilizer on the loss of N and P in coastal saline region were studied by field plot experiments. Results showed that nitrate was the main type of nitrogen in the surface runoff,and the loss of nitrogen in the early period was higher than in the later period. The content of dissolved phosphorus in the surface runoff was close to particulate phosphorus in the early period,while the particulate phosphorus was the dominant in the later period. The loss of total nitrogen （TN） and total phosphorus （TP） from the treatment with 20 percent increment of chemical fertilizer was higher than in the normal （recommended） chemical fertilizer treatment as well as in the treatment with 20 percent reduction. Results also showed no observable difference between the normal chemical fertilizer treatment and the treatment with 20 percent reduction of chemical fertilizer. The organic-inorganic compound fertilizer treatment enhanced the loss of TN and TP compared with the chemical fertilizer treatment under the same nutrient level. Groundwater nitrate content of each treatment was high,and it was higher in the treatments with 20 percent increment of chemical fertilizer and organic-inorganic fertilizer than in other treatments. No clear difference in nitrate content was found between the 0.5 m and 1.0 m depths below the soil surface after 5 days from fertilization,indicating a weak ability of the soil to intercept nitrate-nitrogen.