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在一个长期灌溉施肥(fertigation)(通过在灌溉水中加入肥料而进行施肥)的试验中,选二棵柑桔树,进行了一年的N素效率和平衡研究,试验期间,把K~(15)NO_3施于22年树龄的长期施高氮和氮素贫缺的Shamouti桔,试验结束时,把整株树掘起,然后测定树体各部分和土壤N素分布情况。结果表明,二个处理土壤和树体~(15)N的总回收率相似,分别为61.7%和56%,但在树体和土壤中分布不同,土壤中肥料氮回收率高氮明显高于低氮处理。在新生器官,如果实、枝条和叶中,来自肥料的氮素比例最高,根和枝条仅6～14%N吸自标记肥料氮。在N_3处理中,叶子和果实吸自肥料的氮,仅分别为20.9%和23.4%,表明氮可从老器官向新组织转移。有证据表明,氮主要贮藏于木质的枝条中,同时根中标记肥料氮的含量相当低。
During a long-term fertigation (fertilization by adding fertilizers to irrigation water), two citrus trees were selected for one year of N-efficiency and balance studies. During the experiment, K ~ (15) ) NO_3 was applied to Shamouti oranges with long-term high nitrogen and nitrogen deficiency at the age of 22 years. At the end of the experiment, the whole tree was excavated, and then the distribution of N in various parts of the tree and soil was determined. The results showed that the total recoveries of ~ (15) N in the two soils were similar, 61.7% and 56%, respectively. However, they were distributed differently in the tree and soil, Low nitrogen treatment. In fresh organs, nitrogen, derived from fertilizers, is the highest in roots, shoots and leaves, while nitrogen and nitrogen in shoots and shoots are only 6-14%. In N_3 treatment, leaves and fruits were drawn from fertilizer nitrogen, only 20.9% and 23.4%, respectively, indicating that nitrogen could migrate from the old organ to the new tissue. There is evidence that nitrogen is mainly stored in woody shoots, while the content of labeled nitrogen in the roots is quite low.