种植绿肥对作物产量和细菌群落稳定性的影响

为深入研究青海高原地区长期种植绿肥，减施化肥条件下小麦/油菜产量及土壤理化性状及微生物群落的变化，通过2011年建立的定位试验，设GF0（毛苕子作为绿肥，不施用化肥）、GF60（毛叶苕子配施60%化肥）、GF70（毛叶苕子配施70%化肥）、GF80（毛叶苕子配施80%化肥）、GF90（毛叶苕子配施90%化肥）、GF100（毛叶苕子配施100%化肥）、F0（休耕并且不施化肥）、F100（休耕并且施用100%化肥）共8个处理，利用高通量测序等技术，研究了种植利用绿肥减施化肥条件下小麦和油菜的产量、土壤性质和微生物群落结构的变化特征.结果表明，在保证小麦、油菜不减产的基础上，种植绿肥后茬作物减施化肥达到30%左右.绿肥配施减量化肥对土壤肥力有显著的提升作用，特别是土壤有机碳和全氮含量有明显的提高，分别提高1.34%~7.46%、2.16%~7.48%.化肥与绿肥配施增强了土壤微生物群落多样性，其中酸杆菌门和变形菌门是本研究土壤中的优势菌群.共生网络分析表明，绿肥处理提高了细菌群落的稳定性和抗干扰能力，同时绿肥应用增加了细菌群落中的关键物种.本研究表明，不同土壤微生物丰度受种植模式、施肥量影响很大，长期种植绿肥、减施化肥提高了土壤微生物丰度和多样性，增强微生物群落的稳定性.种植绿肥条件下化肥减肥量30%左右保证作物稳产可为当地的施肥管理提供参考.

Green manuring increased crop yields and the stability of bacterial community

In order to provide theoretical support for the effects of reducedfertilizer in hairy vetch-wheat/oilseed rape rotation system on crop production and soil fertility in Qinghai Plateau. a location field experiment about hairy vetch-wheat/oilseed rape rotation established in 2011 was used in this study. The experiment including eight treatments, e.g., only green manure (GF0), green manure and 60% of chemical fertilizer (GF60), green manure and 70% of chemical fertilizer (GF70), green manure and 80% of chemical fertilizer (GF80), green manure and 90% of chemical fertilizer (GF90), green manure and 100% of chemical fertilizer (GF100), only 100% of chemical fertilizer (F100), and the no-fertilizer control (F0). The wheat and oilseed rape yields, soil properties and microbial community structures were measured. Results showed that the green manure-wheat/oilseed rape rotation system could reduce about 30% chemical fertilizer without reduction of wheat and oilseed rape yields, when compared with F100. Green manure combined with reduced chemical fertilizer improved soil fertility, especially increasingthe contents of soil organic C and total N by 1.34%~7.46% and 2.16%~7.48%, respectively.Green manure combined with reduced chemical fertilizer increased the diversity of soil microbial, and the most abundant phyla were Acidobacteria and Proteobacteria. The results of co-occurrence networks showed that green manuring increased the percentages of negative correlations andmodularity of the networks, indicating that application of hairy vetch as green manure increased the stability and anti-jamming capability of the bacterial communities. The network roles suggested that utilization of green manure increased the keystones in the bacterial community. It was concluded that the microbial diversity and abundance were affected by the cropping system and fertilization amounts. The utilization of green manure can reduce 30% of chemical fertilizer without reduction of wheat and oilseed rape yields. The reduced fertilizer amount could be a reference to the local fertilizer management practices and will give a theoretical support for this agricultural system.