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采用盆栽试验和15N示踪技术,研究4个不同氮(N)水平对剑麻生长及氮素吸收利用特性的影响。结果表明,施氮显著提高剑麻株高、叶长、叶宽和根粗。施氮处理地上部鲜重、含水量、全氮含量和吸氮量均有所增加,但施氮处理之间差异不显著。剑麻地上部和根系吸收的肥料N随着氮水平增加而增加,各处理整株肥料N比例,以示踪法计算为24.2%~32.6%,差减法计算为34.6%~53.1%。不同氮水平下剑麻氮素利用率变化不明显,整株氮素利用率,示踪法计算为20.0%~22.0%,差减法计算为30.0%~35.7%。可见,剑麻吸收的肥料氮低于土壤氮;剑麻的氮素利用率偏低;以示踪法求得的肥料N比例和氮素利用率均低于以差减法求得的结果。
Pot experiments and 15N tracing technique were used to study the effects of four different nitrogen levels on the growth and nitrogen absorption and utilization of sisal. The results showed that nitrogen application significantly increased sisal height, leaf length, leaf width and root diameter. The fresh weight, water content, total nitrogen content and nitrogen uptake of aboveground parts increased with nitrogen application, but there was no significant difference between them. Fertilizer N absorbed in the upper part and root of sisal increased with the increase of nitrogen level. The proportion of N in the whole plant was calculated as 24.2% -32.6% by tracer method and 34.6% -53.1% by subtraction method. The nitrogen utilization rate of sisal did not change significantly under different nitrogen levels. The utilization rate of whole plant nitrogen, tracing method was 20.0% ~ 22.0%, and the subtraction method was 30.0% ~ 35.7%. It can be seen that the nitrogen content of sisal is lower than that of soil nitrogen; the nitrogen utilization rate of sisal is low; the N content and nitrogen utilization rate obtained by tracer method are lower than those obtained by subtraction method.