Fungal community structure in relation to manure rate in red soil in southern China

Abstract

The influence of manure application rate on the structure of the soil fungal community was investigated in a three-year plot experiment using high-throughput sequencing. In addition, soil environmental factor driving the variation of fungal community structure was explored by redundancy analysis of soil chemical properties. Pig manure at low rates of 1.75 or 3.5 t·ha−1 yr−1 or at high rates of 7, 14 or 28 t·ha−1 yr−1 in combination with chemical fertilizer was applied to red soils from three parent materials: granite (GR-soil), red sandstone (RS-soil) and red clay (RC-soil). The results indicated a higher fungal disease index of root rot in GR-soil than that in RS-soil or RC-soil, and higher manure application rates greatly decreased the incidence of peanut disease in GR-soil. The abundances of the most fungi at the order level, the number of OTUs (operational taxonomic units) and the diversity of the fungal community all sharply decreased with increasing manure application rate, and more significant decreases occurred especially at the low manure rates. Redundancy analysis and curve fitting revealed that the diversity of the fungal community was correlated with the increase in soil available phosphorus, exhibiting a striking exponential relationship with available phosphorus. It is suggested that producers should consider an appropriate manure rate as one tool for disease suppression due to its good impact in some soils. More research should probably be done to define what soil factors might play a role in determining when manure applications may have the disease suppressive impact.