Short-term effects of application of reduced phosphorus fertilizer combined with manure on the community complexity and stability of arbuscular mycorrhizal fungi

Abstract:

[Objective] To investigate the community characteristics, network complexity, and community stability of arbuscular mycorrhizal fungi (AMF) in the soil applied with reduced phosphorus (P) fertilizer combined with manure, and reveal the short-term effects of soil properties on the network characteristics and community stability of AMF community in the context of manure substitution for chemical fertilizers. [Methods] On the basis of the long-term inorganic P fertilizer application experiment started in 2012, a split plot experiment was designed with the application of reduced P fertilizer combined with manure and started in 2018. Six treatments were designed:inorganic P supply at 0, 75, and 150 kg/hm² and 30% reduction in inorganic P fertilizer (i.e., 0, 52.5, and 105 kg/hm²) combined with manure at 3 187 kg/hm², with three replicates for each treatment. High-throughput sequencing and bioinformatics analysis were employed to explore the short-term effects of application of reduced P fertilizer+manure on the network characteristics and stability of the AMF community in soil. [Results] The alpha diversity of AMF decreased in the case of application of reduced P fertilizer+manure compared with that in the case of inorganic P fertilization. Glomus and Paraglomus were the dominant taxa of AMF in each treatment. The average degree and average weighted degree of the network reached the maximums under the appropriate amount of P fertilizer, and were higher in inorganic P treatments than in reduced P fertilizer+manure treatments. The number of negative correlation links in the network increased with the increase in P application in inorganic P treatments and decreased with the increase in P application in reduced P fertilizer+manure treatments. The application of reduced P fertilizer+manure improved the stability of AMF community by increasing the negative/positive cohesion ratio. Compared with indicator species and keystone taxa, dominant taxa are closely associated with the stability of AMF community. [Conclusion] In acid purple soil, short-term application of reduced P fertilizer+manure regulated the alpha diversity and dominant taxa of AMF by changing soil pH, available P, and soil organic matter, thereby affecting the network complexity and stability of AMF community.