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.

Key words:arbuscular mycorrhizal fungi;combined application of manure;community diversity;network complexity;community stability