不同水分条件与毕节烟田土壤氮素淋失的关系

Relationship Between Different Water Conditions and Nitrogen Leaching in Tobacco Field of Bijie

为了研究不同水分状况对毕节烟田土壤氮素淋失的影响,采用盆栽试验比较了2种土壤在3个土壤含水量层次下,土壤渗滤液中总氮含量、各氮素形态、硝态氮淋失量之间的差异。结果表明,在不同水分状况下,毕节烟田土壤渗滤液可溶性总氮含量随土壤含水量的增加而明显提高,其回归方程为y=0.447lnx-0.222;毕节烟田土壤渗滤液中的主要氮素形态是可溶性有机氮和硝态氮,铵态氮所占比例较低;土壤硝态氮的累积程度和水分入渗量是决定毕节烟田土壤硝态氮淋失量的重要影响因子;毕节市金沙县的紫色土其氮素淋失风险显著高于七星关区的黄壤。

To find out the effects of different water conditions on nitrogen leaching in tobacco field of Bijie, a pot experiment was conducted to determine the difference of total nitrogen content in soil leachate, various forms of nitrogen and nitrate leaching loss between the two kinds of soil under three soil moisture levels. The results showed that： the concentration of soluble total nitrogen in the percolation water was significantly improved with increasing soil moisture, the regression equation was y=0.447lnx- 0.222. Soluble organic nitrogen and nitrates were the major forms of nitrogen in soil percolation water, while ammonium had a lower proportion compared with soluble organic nitrogen and nitrates. The accumulated soil nitrate and amount of infiltration were the important factors to determine nitrate leaching in Bijie tobacco field. The nitrogen leaching risk was significantly higher in purple soil than yellow soil.