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以江苏省泗洪县陈圩林场不同林分密度的‘南林95’杨(Populus×euramericana cv.Nanlin-95)人工林为试验林,利用原位离子交换树脂法对不同季节的外源无机氮输入量以及土壤0~20 cm的无机氮库进行测定。结果表明:外源无机氮输入量随着季节的变化均呈现出一定的变化规律,硝态氮在8—10月输入量较大,铵态氮2—4月输入量较高;高密度林分在5—10月之间的无机氮输入量比低密度林分的高。杨树人工林无机氮含量和无机氮库的变化趋势也呈现出季节变化规律,硝态氮含量在生长季节(5—10月)较高,铵态氮含量在11月较高,无机氮库总量在2月时最低;低密度林分无机氮库总量要低于高密度林分的无机氮库总量,8月时,两种密度林分的无机氮库有差异。
Taking the Populus × euramericana cv. Nanlin-95 plantation with different stands density in Chenwu forest farm of Sihong County, Jiangsu Province as test plantation, in situ ion exchange resin method was used to study the effects of exogenous inorganic Nitrogen input and 0 ~ 20 cm soil inorganic nitrogen pool were measured. The results showed that the input of exogenous inorganic nitrogen varied with the seasons. The input of nitrate nitrogen was larger in August to October and the input of ammonium nitrogen was higher in February to April. The input of high density forest Inorganic nitrogen input between May and October was higher than that of low-density forest. The change trend of inorganic nitrogen and inorganic nitrogen in poplar plantation also showed a seasonal variation. The content of nitrate nitrogen in the growing season (May-October) was higher, the content of ammonium nitrogen was higher in November, the inorganic nitrogen The total amount of inorganic nitrogen in the low-density forest was lower than that of the high-density forest in August, and there was a difference in the inorganic nitrogen pool of the two kinds of density forest in August.