作 者 ：关大伟,李力,岳现录,马鸣超,张武,李俊
期 刊 ：植物营养与肥料学报 2014年 20卷 6期 页码：1497-1504
Keywords:soybean, 15Nnaturalabundancemethod, efficiencyofbiologicalnitrogenfixation, amountofbiologicalnitrogenfixation,
摘 要 ：【目的】根瘤菌与大豆共生结瘤固氮是大豆的重要氮素来源之一,而我国在大豆生产中普遍过量使用化学氮肥,不仅增加了生产成本,而且严重抑制了大豆的生物固氮效率。因此在生产中充分发挥生物固氮作用、 合理施用化学氮肥、 降低大豆生产成本是我国发展大豆产业的重要措施,本文对我国大豆主产区生物固氮潜力及其分布特征进行了研究,旨在了解不施氮肥条件下不同大豆产区生物固氮的最大供氮能力,为大豆的合理施肥和充分发挥生物固氮作用提供理论依据。【方法】采用15N自然丰度法,在2011年和2012年测定了在不施用氮肥条件下我国4个大豆主产区包括黑河、 大庆、 长春、 铁岭、 济宁、 延安、 南宁等7个试验点在内的大豆生物固氮效率、 生物固氮量及其对产量的贡献。15N自然丰度法的原理是利用非固氮参照作物从土壤中吸收的15N丰度高于固氮植物,根据两者的15N自然丰度差异估算出固氮植物的生物固氮率。所选的非固氮参照作物必须同大豆生长季一致,并且各试验点选用同一种非固氮植物以保证各地数据的可比性。通过查阅文献,有研究使用玉米作为参照作物,并且符合上述要求,因此本研究选择玉米作为非固氮参照作物。【结果】在不施氮肥条件下,我国大豆在正常降水年份的生物固氮效率为47%～70%,其中铁岭最高为60%～70%,黑河最低为47%～54%;大豆的生物固氮量在N 92～150 kg/hm2之间变化,其中籽粒中的生物固氮量占总固氮量的65%～81%,生物固氮量最高的试验点为长春,最低的试验点为延安;生物固氮对产量的贡献在1039～1867 kg/hm2之间,其中最高的试验点为长春,最低的试验点为延安;在延安试验点苗期～开花期极度干旱的2011年,大豆缺水严重抑制了根瘤菌的数量和固氮酶的活性,其生物固氮效率、 固氮量及对产量的贡献均达极低水平,分别为15%和N 24 kg/hm2和245 kg/hm2。【结论】我国大豆不同主产区的生物固氮潜力存在较大差异,并且具有明显的分布规律。生物固氮效率以温带的铁岭为最高,向北至寒温带的黑河、 向南到亚热带的南宁均呈现逐渐降低的趋势。受种植密度等因素的影响,大豆生物固氮量及其对产量贡献的分布规律与生物固氮效率不完全一致,其中东北地区最高,其次是济宁和南宁,延安最低。
Abstract:【Objectives】Biological nitrogen fixation (BNF) is one of the important sources of nitrogen for soybean.ExcessiveN fertilizerinhibitesthe efficiencies of BNF and increases the cost of soybean production in China. Understanding the N-fixtion capacityof BNF without N fertilizer input in different soybean planting regions in China is the key for reasonable N fertilization. For the reason weinvestigated potential of BNF and its distribution characteristics in this paper.【Methods】The method of 15Nnatural abundance was employed to determine the BNF efficiency in 2011-2012, the amounts of BNF and their contributions to the grain yield under no nitrogen fertilization conditions in 4 soybean producing regions of China, includeding Heihe, Daqing, Changchun, Tieling, Jining, Yan’an and Nanning city. This technique is based on principle that the 15N natural abundance of the reference plant which only obtains N from soil is higher than that of N2-fixing legume, then the difference can be interpreted quantitatively to assess contribution of BNF. The reference plant must have same growth season with soybean, and it is also the same plant in different experimental sites to ensure comparability of data. Maize which met above requirements was selected as the reference plant in this study.【Results】 In normal rainfall years, the variation of the soybean BNF efficiency of different sites is observed between 47%-70%. Thelowest BNF efficiency is at Heihe and highest at Tieling. The amounts of BNF are in the range of N 92-150 kg/ha with the lowest in Yan’an and the highest in Changchun, and their fixed N amounts in grain account for 65%-81%. The contribution rates of BNF to grain yields are 1039-1867 kg/ha with the lowest in Yan’an and the highest in Changchun. In the Yan’an site, serious drought appeared before the flowering stage in 2011, the number of nodule and the nitrogen-fixzation activity were intensely inhibited, causing the decreases of the BNF efficiency. The efficiency, amount of BNF and the contribution rate to grain yieldwere decreased to 15%, N 24 kg/ha and 245 kg/ha respectively. 【Conclusions】The findings above indicate that there are differences in the potential of BNF among the soybean planting regions, and also have obvious distribution characteristics. The BNF efficiencies gradually decrease from Tieling (temperate zone) northwards to Heihe(cold temperate zone) and southwards to Nanning (subtropical zone). Due to various planting densities and other factors in different sites, the variation of the amounts of BNF and their contribution to grain yields are the highest in Northeast China, middle in Jining and Nanning and the lowest in Yan’an.
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