The characteristics of nitrogen utilization and source of Rubber cultivar (Yunyan 774) under different nitrogen levels,including 2.0 g perpot,4.0 g perpot and 6.0 g perpot,were explored through pot experiment by 15N urea isotope labeling,respectively. The results showed that with the increase of N supply,the dry matter accumulation and nitrogen residue as well as residue rate of rubber cultivar increased,while the nitrogen utilization rate decreased(N2 37.45%>N4 26.33%>N6 21.22%). The dry matter accumulation order of various organs of rubber under different nitrogen levels was stem > root > leaf;The nitrogen content order of nitrogen fertilizers was leaf> stem > root;The utilization rate order of nitrogen fertilizer in leaves was the largest,followed by stems and roots. There was the highest fertilizer nitrogen and total nitrogen in leaves,which had the highest distribution rate as well as the strongest absorption competitive ability of fertilizer nitrogen .%采用盆栽试验,应用15N 同位素尿素标记,研究了不同供氮水平(每盆2.0、4.0、6.0 g)下云研774橡胶树幼苗氮素的吸收利用及来源特征.结果表明,随供氮水平的提高,呈现橡胶树幼苗氮素和干物质积累量增加、对肥料氮素的吸收利用率下降(N237.45%>N426.33%>N621.22%),土壤肥料氮素残留量及残留率增加的趋势.不同供氮水平橡胶树幼苗各器官的干物质积累均呈现茎>根>叶,肥料氮的积累量呈现叶>茎>根;氮肥利用率表现为叶最大,其次为茎、根;叶片积累的肥料氮、全氮最多,对肥料氮的吸收竞争能力最强.
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