氮肥基追施比例对芝麻产量和氮素吸收、分配的影响

Optimal ratio of nitrogen basal application and top-dressing for N uptake,distribution and yield of sesame

【目的】研究实现芝麻高产、提高氮肥利用效率、减少氮肥残留的氮肥最佳基追比例。【方法】采用盆栽试验,供试芝麻品种为‘郑太芝1号’,设置4个氮肥基追比例处理,氮肥底施与初花期追施比例分别为1∶0(N1∶0)、2∶1(N2∶1)、1∶2(N1∶2)、0∶1(N0∶1)。利用15N示踪技术,每盆施含有15N标记的总氮0.9g,分析各处理芝麻产量及氮素的吸收、分配特征。【结果】不同处理相比,N2∶1处理单株产量最高,N1∶2处理次之,N2∶1与N1∶0、N0∶1处理差异达显著水平。在初花期,N2∶1处理,芝麻单株生物量和植株总吸氮量均最高,不施基肥的N0∶1处理最低;各处理植株对肥料氮的吸收表现为N1∶0>N2∶1>N1∶2,对土壤氮的吸收以N2∶1最高;肥料氮和土壤氮在各器官中的分配均为叶>茎>根。在成熟期,N2∶1处理的单株总生物量最大,单株籽粒吸氮量和总吸氮量也最高,N1∶0处理最低,两者差异达显著水平;植株对肥料氮和土壤氮的吸收比例为23.7%~29.1%和70.9%~76.3%;对肥料氮和土壤氮的吸收均为籽粒>叶片>茎>蒴皮>根,籽粒吸氮量明显高于其它器官,籽粒占总吸氮量的33.0%~44.3%。N2∶1处理氮肥利用率最高,为32.5%,N2∶1、N1∶2、N0∶1处理间差异不显著,但均与N1∶0(17.8%)差异达显著水平。不同处理芝麻收获后土壤15N回收率以N2∶1处理的最低(16.2%),N0∶1处理的最高(31.3%)。【结论】在本试验条件下,氮肥底施与初花期追施比例为2∶1时,芝麻产量和生物量以及氮肥利用率最高,氮肥土壤残留量最少,是最佳氮肥基追施比例。

【Objectives】The study aimed to ascertain the appropriate application ratio of nitrogen in basal and topdressing to achieve high sesame yield and quality, high fertilizer use efficiency, and low soil N residue.【Methods】A pot experiment using the 15N-tracer technique was conducted with white sesame cultivar of ‘Zhengtaizhi 1’ as tested material. At the base of same N application rate of 0.9 g 15N-labeled urea per pot, the N was applied in ratio of basal to topdressing (at the initial flowering stage) of 1∶0 (N1∶0), 2∶1 (N2∶1), 1∶2 (N1∶2), and 0∶1 (N0∶1). The N uptake, distribution and yield of sesame were examined.【Results】Among the four treatments, N2∶1 had the highest single plant yield, followed by N1∶2, and the yield difference with both N1∶0 and N0∶1 reached a significant level. The total uptake of nitrogen per plant at the initial flowering stage decreased with the decrease of ratio of basal fertilizer, the uptake of N per plant was the highest in N2∶1 treatment and the lowest in N0∶1 treatment. The N uptake from fertilizer by sesame at the initial flowering period was in order of N1∶0 > N2∶1 > N1∶2, and that from soil was the highest in N2∶1 treatment. The distribution of N both from soil and fertilizer was in order of leaves > stems > root at the initial flowering period. At maturity, the largest single plant biomass, the highest seed N uptake and total plant N uptake were obtained in N2∶1 treatment, while the lowest in N1∶0 treatment, with a significant difference in the items between N1∶0 and N2∶1 treatments. The proportion of fertilizer N uptake by plant was 23.7%?29.1%, that of soil N was 70.9%?76.3%. The N uptake from both fertilizer and soil was in order of seeds > leaves > stems > capsule > root, and the seed N uptake was significantly higher than others and accounting for 33.0%?44.3% of total plant N uptake. The fertilizer N utilization rate of the four treatments was in range of 17.8%?32.5%. The fertilizer N utilization rate in N2∶1 treatment was significantly higher than that in N1∶0, and the difference among the N2∶1, N1∶2, and N0∶1 was not significant. The recovery rate of 15N in different treatments varied significantly from 16.2% in N2∶1 to 31.3% in N0∶1 at harvest.【Conclusions】Under the experimental condition, applying nitrogen fertilizer in ratio of basal to topdressing of 2∶1 could produce the highest sesame yield and fertilizer nitrogen use efficiency, and leave less in soil, so is thought to be optimal nitrogen application strategy.