不同氮水平对甘蔗氮素利用及土壤氮素残留的影响

以新台糖22号(ROC22)为试材,设施用15N标记的尿素2.5 g pot-1、5.0 g pot-1及7.5 g pot-13个处理,研究施氮水平对甘蔗氮素利用效率及土壤氮素的影响。结果表明,随氮肥施用水平的提高,甘蔗干物质积累、氮素积累、来源于肥料氮素的比率不同程度增加,同时土壤碱解氮含量、硝态氮含量、肥料氮素残留量及肥料氮素残留率显著增加,但甘蔗氮肥利用率显著下降;施氮水平还明显影响甘蔗各器官的干物质分配、氮素分配、氮肥利用率及氮素在不同土层的分布。本试验条件下,甘蔗氮肥施用土层深度为20 cm、尿素施用量为5.0 g pot-1较为适宜。

Effects of Nitrogen Fertilizer Levels on Nitrogen Utilization and Residue in Sugarcane-planted soil

The study was conducted to research the effects of nitrogen fertilizer levels on nitrogen utilization and nitrogen residual by sugarcane cultivar ROC22.There were three treatments 15N-labeled urea 2.5 g pot-1,5.0 g pot-1 and 7.5 g pot-1 respectively.The results thowed that dry matter accumulation,nitrogen accumulation and the proportion of N from nitrogen fertilizer in sugarcane increased with the levels of nitrogen fertilizer increment.The alkali hydrolytic N content,NO3--N content,nitrogen residual amount and nitrogen residual ratio of soil were also increased significantly,while nitrogen utilization ratio in sugarcane decreased significantly.The nitrogen fertilizer application had obviously influence on dry matter distribution,nitrogen distribution,nitrogen utilization ratio in sugarcane organ and nitrogen distribution in soil.In the present study,the suitable amount and location of nitrogen fertilizer applied were 5.0 g urea pot-1 and 20 cm soil depth.