Effects of nitrogen and phosphorus addition on soil microbial community in a secondary tropical forest of China

Effects of phosphorus addition on soil microbial biomass and community composition in a subalpine spruce plantation

“…This may depend on the higher C availability in the HP treatment. Additionally, an increase in F:B ratio induced by P addition was observed in tropical forests [3,5]. This can be due to the facts that P availability in the tropical forests is always low and microbial utilization of C is constrained by P [5].…”

“…Furthermore, the limited experimental data is rather controversial, and there is no general agreement on the effects of P availability on soil microbial biomass and community composition. DeForest et al [4] found no significant changes in soil microbial biomass after P addition in either unglaciated or glaciated soil of temperate deciduous forests, while Li et al [5] reported that P addition increased soil microbial biomass and fungi:bacteria (F:B) ratio and altered the community composition in P-deficient tropical forests. Other scholars found positive, neutral even negative effects of P on soil microbes in temperate forests [6e8].…”

“…Additionally, Liu et al [3] found that responses of soil microbial biomass and community composition to P addition varied in three forest types in tropical China. These inconsistencies imply that the effects of P addition on soil microbial biomass and community composition may vary with the forest biome at global scale and the forest type at local scale, and that the exact relationship between P availability and soil microbial community is poorly understood [4,5]. Given the distinct discrepancy in climate, vegetation and soil types across forest biomes and among forest types, more studies from specific forest ecosystems are indispensable to conclude the effects of P availability on soil microbes.…”

“…To date, multiple mechanisms have been proposed to explicate the P effects on soil microbes [e.g., 3,5,7,9] (Fig. 1).…”

“…1). For instance, P addition can increase litter fall and fine root biomass, resulting in increased C availability to soil microbes, and eventually improved soil microbial biomass and altered the community composition [3,5]. Besides, the relieved P constraints and changes in soil pH and osmotic potential after P addition can also influence the microbial growth [5,7,10].…”