草业学报2025，Vol.34Issue(6)：110-121,12.DOI:10.11686/cyxb2024369
保护播种下紫花苜蓿根际土壤氨氧化和反硝化微生物群落对糜子种植比例变化的响应
Effects of different planting ratios of broomcorn millet(Panicum miliaceum)on ammonia-oxidizing and denitrifying microorganisms in rhizosphere soil of alfalfa(Medicago sativa)
摘要
Abstract
Companion planting of broomcorn millet(Panicum miliaceum)with alfalfa(Medicago sativa)can improve nitrogen utilization.To explore the mechanism of this effect,we investigated the impact of different planting ratios of broomcorn millet and alfalfa on ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),denitrifying microorganisms(nirK-,nirS-,and nosZ-containing microbes),and other soil factors in alfalfa rhizosphere soil under companion planting in the dry farming area of the Loess Plateau.Four broomcorn millet-alfalfa planting ratios[1∶1(1P1M),1∶2(1P2M),1∶3(1P3M),and 2∶3(2P3M)]were established with alfalfa monoculture(M)as the control.The diversity,structure,composition,and co-occurrence network of ammonia-oxidizing and denitrifying microorganisms in alfalfa rhizosphere soil were determined by high-throughput sequencing,and their correlations with soil factors were analyzed.The results showed that,as the ratio of broomcorn millet increased,the soil total nitrogen content and stable carbon and nitrogen isotope values increased,and significantly increased in 2P3M(P<0.05);and the soil organic carbon content first decreased and then increased,with a significant decrease in 2P3M(P<0.05).Companion planting increased the richness of ammonia-oxidizing and nosZ-containing microorganisms,but decreased the richness of nirK-containing microorganisms.The alpha diversity of AOA was sensitive to the planting ratio.However,a beta diversity analysis revealed no significant differences in ammonia-oxidizing and denitrifying community structures among the different planting ratios.Nitrososphaera and Nitrosospira were the dominant genera of AOA and AOB,respectively,accounting for over 85%of their communities based on abundance.The denitrifying microbial community was enriched in genera that promote plant growth and nutrient transformation,such as Achromobacter among the nirK-containing microorganisms and Azoarcus among the nirS-containing microorganisms.A co-occurrence network analysis revealed a more complex co-occurrence network of soil ammonia-oxidizing and denitrifying communities in 2P3M than in the other treatments,and this was mainly evident in the network complexity and modularity indicators.The contents of total nitrogen and calcium and magnesium ions were significantly correlated with AOA microbial diversity,and the contents of soil organic carbon and cadmium ions were significantly correlated with AOB and nirS microorganisms.In summary,companion planting affected the diversity,composition,and co-occurrence network of ammonia-oxidizing and denitrifying microorganisms in the rhizosphere soil of alfalfa,revealing the microbial mechanism of efficient nitrogen utilization under this technology.Based on these results,the broomcorn millet∶alfalfa planting ratio of 2∶3 appears to be the most effective for exploiting the advantages of companion planting.关键词
保护播种/氨氧化/反硝化/功能基因/多样性/共现网络Key words
companion planting/ammonia oxidation/denitrification/functional gene/diversity/co-occurrence network引用本文复制引用
李若璇,李升郅粲,陈奕彤,孙雨豪,杨培志,崔彦农,龙明秀,何树斌..保护播种下紫花苜蓿根际土壤氨氧化和反硝化微生物群落对糜子种植比例变化的响应[J].草业学报,2025,34(6):110-121,12.基金项目
国家重点研发计划项目(2022YFD1300803)和国家自然科学基金(32071878)资助. （2022YFD1300803）
