供氮水平对冬马铃薯氮肥利用效率及氮素去向的影响

Effects of Nitrogen Application Levels on Nitrogen Utilization Efficiency and Fate of Fertilizer for Winter-planting Potato

以马铃薯费乌瑞它为试材,设施用纯N 80、160、240 kg hm-2共3个处理,采用田间微区15N示踪技术,研究施氮水平对冬马铃薯干物质积累、氮素利用、氮素残留及氮素损失的影响。结果表明,施N量在80~160 kg hm-2,马铃薯植株及其块茎、根、茎、叶干物质积累量明显增加,但继续增加施N量,块茎干物质积累量增加不明显,根、茎及叶干物质积累量则下降;提高施N水平,马铃薯吸收的肥料N、肥料N来源比率、肥料N残留量和损失量、肥料N残留率和损失率明显增加,但肥料N吸收利用率显著下降;施N水平还明显影响肥料N在马铃薯各器官尤其是块茎的分布率,以及在不同土层尤其是0~15 cm土层的残留分布。因此,本研究条件下,马铃薯施N水平应控制在160 kg hm-2以下,以保证马铃薯高产、防止过量肥料N残留及减少污染风险。

A field micro- plot experiment was carried out to investigate the effects of nitrogen application levels(15N 80,160, and 240 kg hm- 2) on dry matter accumulation, fertilizer N utilization, fertilizer N residue and fertilizer N loss under potato cultivation. The results showed that the dry matter accumulation in plant, tuber, roots, stalks and leaves increased obviously as nitrogen fertilizer increased from 80 kg hm- 2to 160 kg hm- 2. When the amount of nitrogen application was higher than 160 kg hm- 2, the dry matter accumulation in tuber still increased slightly, and the dry matter accumulation in root, stalk and leaf decreased. With the increase of N fertilizer rate, the amount of fertilizer N accumulation and the proportion of fertilizer N in potato plant increased, and the amount and ratio of N remained in soil and lost from fertilizer also improved. However, the nitrogen utilization ratio by potato plant decreased significantly.Nitrogen fertilizer application had obviously influence on nitrogen distribution ratios in potato organs, especially in tuber, and nitrogen residue in soil depth profile, especially in 0 ~ 15 cm layer. Therefore, proper rates of N application( less than 160 kg hm- 2) would be favorable to improve potato tuber yield and fertilizer N utilization efficiency, and to prevent excessive accumulation of fertilizer N in soil and reduce the risk of non- point source pollution.