抚仙湖流域砾质土有机及常规肥料淋溶模拟研究

Simulated Test of Nitrogen and Phosphorus Leaching from Gravel Soil Applied with Organic Manure and Conventional Fertilizer at the Watershed of the Fuxian Lake

利用不同高度土柱进行模拟淋溶试验,比较研究了抚仙湖流域砾质土壤有机及常规肥料N、P流失规律及水体污染风险。试验结果表明:随着灌溉次数的增加,有机肥料淋洗液中TDN(可溶性总N)浓度先升后降,而常规肥料则持续下降;除20cm高度土柱常规肥料TDP(可溶性总P)浓度快速下降外,其余各淋洗液中TDP浓度变化幅度很小。有机及常规肥料土壤N、P淋溶均以NO3--N和PO4-P形态为主。不同高度土柱TDN、TDP的淋失总量平均值,常规肥料分别为有机肥料的157%、52%,可见常规肥料N素淋溶风险大于有机肥料,而P素淋溶风险则相反。

Comparison of organic manure and conventional fertilizer were investigated in a simulated experiment with 20cm-, 40cm- and 60cm-high soil columns on nitrogen and phosphorus leaching and water pollution hazards from soil sampled from the watershed of the Fuxian Lake. Results showed that with the increase of irrigation frequency, TDN concentration in leaching water from organic manure increased gradually to the maximum and then decreased but it decreased continually from conventional fertilizer; the range of TDP concentrations in all the leaching water was narrow except in the leaching water from 20 cm soil column applied with conventional fertilizer. NO3^--N and PO4-P were the main forms of nitrogen and phosphorus in the leaching water from different soil columns. The mean amount of total TDN and TDP leaching loss from conventional fertilizer were 157% and 52% of which from organic manure, respectively, which meant that groundwater pollution hazards of nitrogen due to conventional fertilizer leaching was higher than which due to organic manure, but on the contrary of groundwater pollution hazards of phosphorus.