降雨条件下西安蔬菜地土壤中氮的迁移规律

Migration Law of Nitrogen in Vegetable Soil in Xian under Rainfall Condition

[目的]研究西安市蔬菜地土壤中氮(N)元素在降雨条件下的迁移转化规律。[方法]采用自制的模拟降雨装置,通过室内模拟试验研究了降雨条件下土壤中N的迁移规律。[结果]每次降雨后,各个深度土壤的含N量均比背景值高;土壤含N量的变化呈现出明显的急剧变化段和缓慢变化段。土壤中含N量的最高值均出现在10～20cm土层,最低值出现在60～70cm土层,10和60cm是降雨条件下土壤含N量变化的折点;随降雨次数的增加这2个折点均有向下移动的趋势。在20cm以下土层中,3次降雨后同一深度处土壤的含N量依次为:N第1次>N第2次>N第3次。在60cm土层中,每次降雨后的土壤含N量均达最低值,约为730μg/g。[结论]该研究为合理施用氮肥提供了依据。

[Objective] The purpose was to study the migration and transformation law of nitrogen element in vegetable soil in Xi＇an City under rainfall condition.[Method] The self-made simulated rainfall equipment was used and the migration law of N in soil under rainfall condition was studied through indoor simulated experiment.[Result] After each rainfall,the N content in soil at each depth was higher than their background values;the change of N content in soil showed obvious 2 stages of sharp change and slow change.The high values of N content in soil all occurred in the soil layer at depth of 10-20 cm and their lowest values all occurred in the soil layer at depth of 60-70 cm,the depths of 10 and 60 cm were salient points of N content change in soil under rainfall condition;as the rainfall times were increased,both of the 2 salient points showed trend of moving downward.In the soil deeper than 20 cm,after 3 rainfalls,the N contents in soil at the same depth were as follows：N第1次N第2次N第3次.In the soil layer at the depth of 60 cm,after each rainfall,the N content in soil reached lowest value which was about 730 μg/g.[Conclusion] This study provided basis for reasonable application of N fertilizer.