施氮量对甘蔗伸长期氮肥效率及氮素去向的影响

以新台糖22号(ROC22)为试材,通过网室盆栽试验方法,研究施氮量对甘蔗伸长期氮肥效率与氮素去向的影响。结果表明:甘蔗吸收的氮素15%～27%来源于当季肥料施的氮,73%～85%来自土壤和种茎氮;氮肥利用率为21.78%～26.75%,残留率为61.24%～69.85%,损失率为8.37%～12.02%。增施氮肥,甘蔗干物质积累量、氮素积累量、来源于肥料氮素的比率及氮肥吸收量、氮肥残留量、氮肥损失量以及氮肥残留率明显增加,而氮肥吸收率和损失率明显下降,氮素和干物质在蔗茎的分配呈下降趋势,同时氮素残留分布在0～20 cm土层呈上升趋势,在20～40 cm土层呈下降趋势。

Effect of nitrogen fertilizer rates on utilization efficiency and fate of fertilizer nitrogen at elongating stage of sugarcane

In the present study,the sugarcane cultivar ROC22 was used,and three nitrogen rates treatments were conducted by pot planting in grennhouse to investigat the effects of nitrogen application rates on nitrogen utilization and fate at elongating stage.Results showed that almost 15%~27% of total N was supplied by fertilizer,and 73%~85% came from soil and seed-stem.The efficiency of fertilizer was 21.78%~26.75%,N-fertilizer residue ratio was 61.24%~69.85%,and N-fertilizer loss was 8.37%~12.02%.In addition,with the enhancment of nitrogen application rates,the accumulation of dry matter and nitrogen as well as the proportion of N from N-fertilizer in sugarcane increased obviously.The uptake,residue and loss amount as well as residue ratio of N-fertilizer were also increased significantly,while uptake ratio and loss ratio of N-fertilizer decreased significantly,the distribution of nitrogen and dry matter in stalk displayed a dropping trend.The results also indicated that the N-fertilizer distribution in soil layer of 0~20 cm increased significantly when the nitrogen application rates was increased,but which in soil layer of 20~40 cm decreased significantly.