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

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.