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基于15N示踪技术的烟田肥料氮素再利用分析

Analysis on reutilization characters of fertilizer N in tobacco field with 15N tracing technique

  • 摘要: 为研究后季烤烟对首季残留氮肥的吸收利用情况,2011年利用蒸渗仪设计了不同灌水量(600、800和1 000 mm)和施氮量(15N双标记NH4NO3,90和120 kg/hm2)试验,并于2012-2014年对烤烟不同器官中15N-N(来源于2011年施入的肥料氮素)累积量、土壤中15N-N含量进行了跟踪观测,同时分析了烤烟对首季肥料氮素再利用率的影响因素。结果表明:1)后季烤烟叶、茎和根中来源于首季的肥料氮素累积量,随首季施氮量的增加而增加,但随首季灌水量增加总体上有所下降;2)后三季烤烟对首季施入肥料氮素的总再利用率为10.79%~14.58%,首季灌水量600 mm、施氮量90 kg/hm2处理最有利于后季烤烟对其残留肥料氮素的吸收;3)后三季烤烟对首季施入的肥料氮素的平均再利用率,与首季灌水量呈极显著负相关(P<0.01),与0~20 cm土壤中首季残留肥料氮素量呈显著正相关(P<0.05)。首季灌水主要通过改变其肥料氮素在不同土层中的分配格局,尤其是通过改变0~20 cm土层的肥料氮素含量,来影响后季烤烟对首季施入肥料氮素的再利用,但其具体影响机理仍需进一步明确。综上,后季烤烟能吸收相当比例的前季残留肥料氮素,合理制定前季灌水和施氮制度,对于后季烤烟肥料氮素再利用率的提高至关重要。研究结论可为烟区土壤生态环境的改善及烟草农业的可持续发展提供有益参考。

     

    Abstract: Abstract: In order to study how the later-season flue-cured tobaccos absorb and utilize the fertilizer N that remained by the first season, in 2011, an experiment controlled with different irrigation amount (600, 800 and 1 000 mm) and different fertilizer nitrogen amount (15N double labeled NH4NO3, 90 and 120 kg/hm2) was conducted using the lysimeters, and the 15N-N (fertilizer N originated from 2011) amount in the tobacco organs and the soils were observed during the flue-cured tobacco cultivation from 2012 to 2014. Meanwhile, the impact factors of the tobaccos' reutilization rate to the first-season fertilizer N were analyzed. Results showed that: 1) the amount of fertilizer N that originated from the first season in the later-season tobacco leaf, stem and root, was increased as the nitrogen application increased in the first season, but overall decreased as the irrigation amount increased; 2) the total reutilization rate of the 3 later-season tobaccos to the fertilizer N that applied by the first season was 10.79%-14.58%, and 600 mm amount of irrigation combined with 90 kg/hm2 amount of nitrogen application was most advantageous for the later-season tobaccos to absorb the fertilizer N that remained by the first season; 3) the average reutilization rate of the 3-later season tobaccos to the fertilizer N that applied by the first season, was negatively related with the irrigation amount in the first season (P<0.01), and was positively related with the amount of fertilizer N that remained by the first season in 0-20 cm soils (P<0.05). The first-season irrigation affected the reutilization rate of later-season tobaccos to the fertilizer N that applied by the first season through changing the distribution pattern of the fertilizer N, especially through changing the amount of fertilizer N in the 0-20 cm soils. However, the detailed impact mechanism still needed to be further clarified. Above all, the later-season flue-cured tobaccos can absorb many of the fertilizer N that applied by the earlier season, and the reasonable formulation of irrigation and nitrogen application regimes in the earlier season was extremely important for improving the fertilizer N reutilization rate of later-season tobaccos. The research conclusions can provide useful information for the improvement of the soil ecological environment of tobacco-cultivated areas and the sustainable development of the tobacco agriculture.

     

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