饲料油菜压青还田对后作小麦土壤真菌群落的影响

Effect of forage rape green manure returning to field on soil fungal community in winter wheat field

摘要:

[目的] 从真菌群落角度揭示麦后复种饲料油菜作绿肥对土壤的培肥效果。[方法] 以常规冬小麦-夏玉米一年两作为对照（CK），采用Illumina Miseq高通量测序技术，探讨麦后复种饲料油菜不同播量（S：小播量；M：中播量；L：大播量）与还田时期（D1：9月10日；D2：9月20日；D3：9月30日）下土壤真菌丰度和群落结构。[结果] 与对照相比，随油菜播量增加，还田生物量显著增加，小麦产量先增后减，中播量中期还田产量最高；此外，播量增加，还田时间应提前。饲料油菜还田显著降低了土壤真菌OTU数量和丰富度指数（ACE和Chao1）。真菌群落组成方面，门水平下优势菌群主要有子囊菌门、担子菌门、接合菌门和壶菌门，纲水平下油菜还田相比对照优势真菌所占比例增加。功能预测结果表明，腐生营养型是土壤真菌主要营养类型，占比41.32%-50.72%；且还田后兼性功能营养类群增加至30.05%-40.10%；同时显著提高被孢霉属、枝顶孢属、毛壳菌属、青霉菌属等具有生防功能有益菌的丰度。[结论] 在晋南旱地麦区推广饲料油菜还田有利于改善土壤真菌群落结构；本试验条件下，油菜中播量种植，9月20日还田为最优措施。

Abstract:

[Objective] From the perspective of the soil fungal community, we explored the effect of forage rape in winter wheat-summer forage rape multiple cropping model as green manure returning to field on soil fertility.[Methods] We used the conventional winter wheat-summer maize multiple cropping model as the control(CK), and used Illumina Miseq high-throughput sequencing technology, to investigate the effect of the different sowing rates of rapeseed (S:small seeding rate, 7.5 kg/hm²; M:medium seeding rate, 15 kg/hm²; L:large seeding rate, 22.5 kg/hm²) and returning to the field (D1:September 10; D2:September 20; D3:September 30) on the abundance and community structure of soil fungal.[Results] Our results showed that compared with the control, with the increase of rape seeding rate, the returning biomass increased significantly, the wheat yield increased firstly and then decreased. We could get the highest wheat yield when rape was planted at 15 kg/hm² and returned on September 20. In addition, the amount of sowing increased, and the time of returning to the field should be advanced. Forage rape as green manure returning to field significantly influenced soil fungal Operational Taxonomic Unit numbers and richness indices (ACE and Chao1). Also, we find that in terms of fungal community composition, the dominant flora at the phylum level mainly includes Ascomycota, Basidiomycota, Zygomycota, and Chytridiomycota. At the level of class classification, the proportion of dominant fungi in forage rape returning to the field increased compared with the control. The function prediction results show that saprotroph is the main trophic mode of soil fungi, accounting for 41.32%-50.72%; and the facultative functional group increases to 30.05%-40.10% after returning to the field. At the same time, the abundance of beneficial biocontrol fungi such as Mortierella, Cephalosporium, Chaetomium and Penicillium was significantly increased.[Conclusion] In wheat arid areas of South Shanxi Province, popularizing the forage rape return to the field was beneficial to improve the soil fungal community structure. Under the condition of this experiment, the best method was to plant rapeseed with a medium sowing rate and return to field on September 20.