鉴于实验室培养法和化学浸提法以及田间的土壤袋培养法在反映森林土壤中有效氮的空闲与季节性变化方面,均存在一定缺陷.本文利用离子交换树脂袋法和测定新鲜土壤中无机氮常用的6%KCl浸提法与桦树实生苗对氮的吸收相比较,树脂袋法可以测土森林土壤中的有效氮.6%KCl浸提法虽也获满意结果,但必须缩短采样与分析测定之间的耽搁.而树脂袋法对时间的要求是不严格的. In view of laboratory culture and chemical leaching method and field soil bag culture method in reflecting the availability and seasonal changes of available nitrogen in forest soil, there are some defects.In this paper, ion exchange resin bag method and the determination of fresh soil inorganic Compared with the nitrogen absorption of birch seedlings, the 6% KCl extraction method commonly used for nitrogen can measure the available nitrogen in soil of soil, while the 6% KCl extraction method can obtain satisfactory results, but the sampling must be shortened And analytical determination of the delay between the resin bag method on the time requirements are not strict.