强化生物固氮减少豆田N2O排放

Reduction of nitrous oxide (N2O) emission from agricultural soils is very important for mitigation of global warming effect, and the use of fertilizer Nitrogen(N) is the main source of N2O emission from agricultural soils. This fertilizer-induced N2O emission could be significantly mitigated by reduction of fertilizer-N input via enhancing biological nitrogen fixation (BNF) of leguminous crops. Soybean(Glycine max L. Merr.)is the most widely planted leguminous crop worldwide, but the mitigation potential of BNF on N2O emissions is not yet clear.In this study, silicone tubing sampler will be explored in field trial to quantify the relationship between soybean BNF and N2O production and its mitigation potential; then the impacts of nitrogen rate and forms on soybean BNF and N2O emissions will be studied to explore the the feasibility of regulation soybean BNF.and N2O emissions by fertilizer management; finally, through inoculation with our Rhizobium strains under both lab and field conditions, which have high nitrogen fixation capacity and contain nosZ gene, the feasibility of reduction N2O production during nodule senescence and decomposition by inoculation with specific Rhizobium strains will be tested. These results can not only quantitatively evaluate the mitigation potential of soybean BNF on N2O emissions, but also provide practical measures to reduce N2O emission from agricultural soils by nitrogen fertilization and / or inoculation with specific Rhizobium strains.

减少农田N2O排放对控制全球温室效应十分重要，而化肥氮的施用是目前农田N2O排放的主要来源。通过强化豆科作物生物固氮，可有效减少化肥氮的使用，从而减少农田N2O的排放。大豆是全球种植最广的豆科作物，但其生物固氮减排农田N2O的潜力还未清楚。本研究首先拟通过田间试验，采用硅胶管采样技术定量评价大豆生物固氮与N2O产生的关系及减排潜力；进而研究不同施氮量及不同氮素形态对大豆生物固氮和N2O产生的影响，探讨从化肥氮使用的角度来调控大豆生物固氮及减少农田N2O的途径；最后利用本实验室已有的、含有nosZ基因的高效根瘤菌株系，通过室内试验和田间验证相结合，研究通过接种特异根瘤菌株系，减少大豆根瘤衰老和分解过程中N2O产生的途径。研究结果不仅可定量评价大豆生物固氮减少农田N2O排放的潜力，而且还可为实际生产中通过氮肥施用和/或接种特异根瘤菌株系，减少农田N2O的排放提供切实可行的调控措施。

减少农田N2O排放对控制全球温室效应十分重要，而化肥氮的施用是目前农田N2O排放的主要来源。通过强化豆科作物生物固氮，可有效减少化肥氮的使用，从而减少农田N2O的排放。 大豆是全球种植最广的豆科作物，但其生物固氮减排农田N2O的潜力还未清楚。本研究首先通过田间试验，采用硅胶管采样技术定量评价了大豆生物固氮与N2O产生的关系及减排潜力，表明强化生物固氮能降低豆田N2O排放强度；通过研究不同氮素形态以及施用生物炭后大豆生长，并监测N2O产生，发现添加生物炭之后根际土壤pH值平均上升0.8个单位，土壤含水量提高，有效减少大豆根瘤衰老和分解过程中N2O的产生。研究结果不仅可定量评价大豆生物固氮减少农田N2O排放的潜力，而且还可为实际生产中通过氮肥施用/生物炭，减少农田N2O的排放提供切实可行的调控措施。