College of Resources and Environmental Sciences,Nanjing Agricultural University/Jiangsu Provincial Key Laboratory of Solid Organic Waste Utilization
研究稻麦轮作体系中施氮水平对土壤微生物多样性和异步性的影响，为调控土壤微生物区系以维持作物稳产高产提供理论依据和科学指导。采集长期稻麦轮作体系中不同施氮水平下作物关键生育时期的土壤样品，使用高通量测序技术分析施氮水平对土壤微生物多样性和异步性的影响，研究施氮水平通过改变土壤微生物异步性对稻麦产量产生的影响。小麦季和水稻季的施氮水平梯度分别为：0、50、100、200、300 kg·hm-2和0、90、180、270、360 kg·hm-2；土壤样品采集时期分别为：小麦种植前、拔节期、孕穗期、扬花期、成熟期和水稻种植前、最大分蘖期、拔节孕穗期、开花期、成熟期。施氮水平对各生育时期的土壤微生物多样性和组成均产生显著影响。施氮水平可解释约12%的水稻季微生物丰富度变异（P<0.05）。当小麦季和水稻季施氮水平分别为100和180 kg·hm-2时，土壤微生物群落在作物多个生长阶段均能维持相对较高水平的丰富度。施氮水平可解释9%~11%的小麦季/水稻季微生物群落组成变异（P<0.05）。随着施氮水平的提高，小麦季土壤中Dactylosporanglum、Dongia、Armatimonadetes gp2属和水稻季土壤中Luteolibacter、Arenimonas、Spartobacteria genera incertae sedis、Subdivision3 genera incertae sedis、Cyanobacteria GpI 属的种群异步性显著上升。其中，Dongia与Armatimonadetes gp2属的种群异步性和Luteolibacter、Arenimonas与Cyanobacteria GpI属的种群异步性分别与小麦、水稻的产量存在显著正相关关系。稻麦轮作体系中，土壤微生物多样性受到施氮水平的持续性影响，并随生育期推移而发生变化。施氮水平能够直接影响微生物种群异步性，从而影响微生物功能的互补性，进而对稻麦系统的产量产生积极作用。
【Objective】 The object of this study was to explore the effect of nitrogen addition rate on the relationship between soil microbial diversity and asynchrony in rice-wheat rotation.【Method】We collected soil samples at key growth stages in rice-wheat rotation under different nitrogen addition rates in a long-term experiment and used high-throughput sequencing technology to analyze the effect of nitrogen addition rate on soil microbial diversity. Also, we explored the effects of nitrogen addition rates on yield by altering soil microbial asynchrony. The gradient N addition rates in field experiment were 0, 50, 100, 200, 300 kg·hm-2 for wheat and 0, 90, 180, 270, 360 kg·hm-2 for rice. The key growth stages when soil samples were collected include: fallow before wheat planting, jointing, booting, flowering, and maturing during the wheat season, and fallow before rice planting, max-tillering, shooting, flowering, and maturing during rice season. 【Result】N addition rates impacted soil microbial diversity and composition in each growth stage, and the N addition rate could significantly account for about 12% variations of microbial richness in the rice period. When the N addition rates were 100 or 180 kg·hm-2, soil microbial diversity in the wheat or rice seasons, respectively, was maintained at a relatively high level across all plant developmental stages. Also, the N addition rate could significantly account for 9~11% variations in microbial community composition in the wheat and rice period. With the increase in N addition rate, the asynchrony of some microbial populations was significantly increased during the wheat (e.g. Dactylosporanglum, Dongia, and Armatimonadetes gp2) and rice seasons (e.g. Luteolibacter, Arenimonas, Spartobacteria genera incertae sedis, Subdivision3 genera incertae sedis, and Cyanobacteria GpI). Importantly, the wheat and rice yields showed positive relationships with the asynchronies of Dongia and Armatimonadetes gp2 and with the asynchronies of Luteolibacter, Arenimonas and Cyanobacteria GpI, respectively. 【Conclusion】Nitrogen addition rate has a constant impact on soil microbial diversity in rice-wheat rotation during plant development, which changes microbial population asynchrony, and then improves certain functional complementation to increase crop yield. The results of this study can provide a scientific basis and practical guidance for regulating soil microbial communities to maintain high crop yield.
LI Minghui, FENG Xumeng, GUO Junjie, GUO Shiwei, SHEN Qirong, LING Ning. The relationship between soil microbial population asynchrony and crop yield in rice-wheat rotation with gradient N inputs[J]. Acta Pedologica Sinica,,[In Press]