摘要
采用^(15)N同位素示踪技术,研究了不同施氮水平(0、50、100、150、200、250 kg·hm^(-2))对富士苹果膨大期肥料氮吸收利用、土壤残留和土壤氮素总平衡的影响。结果表明,当施氮水平低于100kg·hm^(-2)时,随施氮水平的提高果实单果质量及产量均显著提高,但当施氮水平高于100 kg·hm^(-2)时,各处理间差异不显著。随施氮水平的提高,肥料氮利用率逐渐下降,且树体吸收的氮来自土壤氮的比例逐渐降低,来自肥料氮的比例逐渐升高;果实膨大期结束时(施氮2个月后),肥料氮的5.98%~13.78%被树体吸收,27.26%~37.38%残留在0~60 cm土体中,48.84%~66.76%通过其他途径损失。随施氮水平的提高,树体吸收的肥料氮量和土壤残留氮量逐渐增加,但肥料氮利用率和土壤残留率却不断降低,同时损失量和损失率不断增加。随施氮水平的提高,0~60 cm土体无机氮(硝态氮+铵态氮)含量显著提高,且残留在土壤剖面中的无机氮主要分布在表土层(0~20 cm)。不施氮和低氮水平(施氮50 kg·hm^(-2))土壤无机氮积累量为负积累,当施氮水平高于100 kg·hm^(-2)时,土壤无机氮积累量均呈正积累。随施氮水平的提高,土壤氮素总平衡由亏缺转为盈余,表明供氮不足会造成土壤氮肥力的下降,过量施氮则会加剧土壤氮素累积,增加氮素污染风险。拟合分析发现,在试验施肥水平土壤氮素总平衡与施氮水平呈线性极显著正相关关系,其回归方程为y=0.2912x–22.481(R^2=0.986),当施氮水平为77.20 kg·hm^(-2)时,土壤氮素达到平衡。
The effect of fertilizer N absorption and utilization, soil N residue and total balance of soil N under different nitrogen levels （0, 50, I00, 150, 200, 250 kg. hm^-2） were studied using 15N isotope tracer technique during Fuji apple fruit rapid-swelling stage. The results showed that when the nitrogen level was lower than 100 kg · hm^-2, the fruit quality and yield increased significantly with the increase of nitrogen level. But when the level of nitrogen application was higher than 100 kg · hm^-2, there was no significant difference among treatments. With the increase of nitrogen application, nitrogen fertilizer utilization rate decreased gradually. The tree nitrogen from soil nitrogen proportion gradually decreased, and the proportion from fertilizer nitrogen increased; At the end of fruit rapid-swelling stage （after 2 months of nitrogen application）, 5.98% - 13.78% of fertilizer N was absorbed by tree, 27.26% - 37.38% of fertilizer N was resided in 0 - 60 cm soil, and 48.84% - 66.76% of fertilizer N was lost by other means. With the increase of nitrogen application rate, the amount of fertilizer N absorbed by trees and soil N residue were increased gradually, but the utilization rate of fertilizer N and soil residual rate were decreased, and meantime, the loss and the loss rate were increased gradually. With the increase of nitrogen application, 0 - 60 cm soil inorganic nitrogen （NO3-N ＋ NHa＋-N） content increased significantly, and residual inorganic nitrogen in the soil profile is mainly distributed in the topsoil （0- 20 cm） . The accumulation of inorganic nitrogen was negative accumulation with no nitrogen and low nitrogen level （50 kg · hm^-2） . When the nitrogen application rate was higher than 100 kg · hm^-2, the accumulation of inorganic nitrogen was positive. With the increase of nitrogen application, soil total nitrogen balance is changed from deficit to surplus, the results showed that low nitrogen application rate could cause the decrease of soil N fertility, and the excessive application of nitrogen could increase the accumulation of nitrogen and increase the risk of nitrogen pollution. The results showed that there was a significant positive correlation between soil total nitrogen balance and nitrogen application rate in the test fertilization level, the regression equation is y = 0.2912x- 22.481 nitrogen rate was 77.20 kg·hm^-2. （R2 = 0.986）, soil nitrogen reached balance when the nitrogen rate was 77.20 kg·hm^-2.
出处
《园艺学报》
CAS
CSCD
北大核心
2017年第8期1569-1578,共10页
Acta Horticulturae Sinica
基金
国家重点研发计划项目(2016YFD0201100)
国家自然科学基金项目(31501713)
国家现代农业产业技术体系建设专项资金项目(CARS-28)
