采用室内土柱淋溶模拟试验,研究了广东南雄烟区3种主要植烟土壤不同施氮水平下氮素淋失特征.结果表明,3种土壤氮素淋失形态主要为硝态氮,淋失主要发生在第1、2、3、4、5次淋洗,其淋失量(Y)随施氮量(x)增加而增加Y紫色土＝1.8889+ 0.0121x+ 0.0012x~2 (R~2=0.9993)、Y牛肝土田＝2.7918-0.0771x+0.0012x~2(R2=0.9861)、Y砂泥田=3.6654-0.0536x +0.0012x~2(R2= 0.9935).在相同施氮量下,3种土壤硝态氮淋失率大小顺序为:紫色土>砂泥田>牛肝土田,其硝态氮累计淋失量与淋洗次数间最佳回归方程为对数方程.淋洗结束后,施氮处理土柱各层硝态氮含量较未施肥处理高,且在相同施氮量时,牛肝土田土柱各层残留硝态氮最高,紫色土最低.%A soil column experiment was conducted to investigate the leaching characteristics of nitrogen at different nitrogen rates in three main types of tobacco-planting soils in Nanxiong, Guangdong province.The results showed that the main leaching nitrogen form was nitrate in these three types of tobacco-planting soils, leaching occurred mainly in the first 2, 3, 4 times leaching, and leaching loss volume of nitrate(Y) increased with increasing rate(x) of nitrogen application Ypurple soil=l.8889+0.0121x+0.0012x2 (R2 =0.9993), Yliver soil=2.7918-0.0771x+0.0012x2 (R2=0.9861), Ysand field=3.6654-0.0536X+0.0012X2 (R2=0.9935).In the same amount of nitrogen application, the nitrate leaching rates of three types of soil were as follows: purple soil＞sand field＞liver soil.The best regression equation between nitrate cumulative leaching loss and leaching times was logarithmic equation.After leaching, the nitrate content in each layer of soil column treated with nitrogen was higher than those without nitrogen application, and in the same nitrogen application rate, the level of residual nitrate in each layer of liver soil column was the highest, but lowest in purple soil.
展开▼
