施氮量对旱地胡麻养分积累、转运及氮素利用率的影响

通过田间试验,研究不同施氮量对胡麻产量、氮素积累转运及氮肥利用率的影响。结果表明,在本试验土壤肥力条件下,无论施氮与否,胡麻各器官不同生育阶段氮素养分吸收、累积和转运规律的基本趋势一致,但其变化量与施氮量有极大关系。施氮量为55.2kg·hm-2时,叶和茎中的氮素向籽粒的转移量、转移率及对籽粒氮素的贡献率最大;叶中氮素向籽粒的转移量、转移率及贡献率要比茎高出89.18%、83.36%和86.36%。胡麻籽粒中47.10%-57.66%的氮素来源于叶,22.46%-30.94%的氮素来源于茎,21.00%-30.48%来自籽粒生长后期从土壤中吸收。施氮量为27.6、55.2、82.8 kg·hm-2时,胡麻籽粒产量分别比不施氮增加了10.21%、16.92%和15.55%。施氮量为27.6-55.2 kg·hm-2时,氮肥的表观利用率、偏生产力分别为51.10%-68.63%和51.54-97.16kg·kg-1。本试验条件下,综合考虑产量、氮肥利用率及生态环境,施氮量在27.6-55.2kg·hm-2为宜。

Effect of different nitrogen level on nutrients accumulation,transfer and nitrogen utilization efficiency of dry land oil flax

Field experiments were carried out to determine the effect of different nitrogen application rates on nitrogen nutrient uptake, transfer and nitrogen utilization efficiency of dry land oil flax. The results indicated that different nitrogen application rates affected nitrogen nutrient uptake, accumulation and transfer at different growth stages, and changes tendencies were consistant. The amount of nitrogen translocation from leaf, translocation efficiency and contribution to grain were 89.18%, 83.36% and 86.36% higher than from stem. The nitrogen in grain, among which 47.10% -57.66% vras transferred from leaf, 22.46% - 30.94% was transferred from stem and 21.00% -30.48% was absorbed from soil. The result indicated that compared to no nitrogen application, the yield of nitrogen treatments （as 27.6, 55.2 and 82.8 kg · hm^-2） increased 10.21%, 16.92% and 15.55%, respectively. The nitrogen transfer amounts, transfer efficiency and contribution efficiency of leaf and stern to grain were maximum when the nitrogen application rate was 55.2kg · hm^-2. With increased nitrogen application rate, apparent nitrogen recovery efficiency of oil flax first increased then decreased. The partial nitrogen factor productivi- ty of oil flax decreased significantly. After taking into account of grain yield, nitrogen utilization efficiency and eco- logical environment, the recommended nitrogen fertilizer rate for dry land oil flax was 27.6 - 55.2kg · hm^-2 at the soil fertility level in our experiment.