不同施氮量对茶园土壤氮淋失的影响
Effects of Different Nitrogen Application Levels on Nitrogen Leaching in Tea Garden Soil
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摘要: 为研究不同施氮量对茶园土壤氮淋失的影响,改良茶园土壤品质,采用室内土柱淋滤试验,研究不同施氮量对强酸性茶园土壤淋溶液pH、NH+4-N和NO-3-N淋溶量的影响。氮肥采用尿素,氮肥用量分别为N0(0kg·hm-2)、N1(150kg·hm-2)、N2(300kg·hm-2)、N3(450kg·hm-2)、N4(600kg·hm-2)。结果表明:施用氮肥降低了土壤pH和土壤淋溶液pH,降低幅度分别为0.08~0.32和0.35~0.81个单位,促进茶园土壤酸化;NH+4-N和NO-3-N的淋溶量均随施氮量的增加而提高;无机氮的淋失率为47.66%~71.31%,淋失量(Y)与施氮量(X)之间的线性回归方程为Y=0.708 X+145.27(R2=0.98);在整个淋洗过程中,NH+4-N和NO-3-N淋溶主要发生在前5次,且主要以NO-3-N的形式淋失,淋失比例为73.50%~89.21%。Abstract: To improve strongly-acidified soil quality of tea garden,a laboratory simulation test of column-leach was carried out to investigate the effects of applying different nitrogen rates on the pH,ammonium nitrogen(NH+4-N)and nitrate nitrogen(NO-3-N)of soil leachate.With urea as nitrogen fertilizer,the different applications were respectively treated with N0(0kg·hm-2),N1(150kg·hm-2),N2(300kg·hm-2),N3(450kg·hm-2)and N4(600kg·km-2).The results showed that the pH values of soil leachate were be decreased by 0.08~0.32and0.35~0.81 with different N application rates,resulting in more soil acidification.The leaching amounts of NH+4-N and NO-3-N were increased by increasing rates of nitrogen fertilizer,and 47.66%~71.31%inorganic nitrogen was lost in leaching water.The regression equation between inorganic nitrogen loss(Y)and N application rates(X)was Y = 0.708 X +145.27(R2=0.98).The leaching of NH+4-N and NO-3-N majorly occurred at the first five times,and the leaching amounts of NO-3-N accounted for 73.50%~89.21% of the total leaching inorganic nitrogen.