Changes in soil phosphorus availability and associated microbial properties after chicken farming in Lei bamboo (Phyllostachys praecox) forest ecosystems

摘要

Bamboo-chicken farming (BCF) is a popular bamboo complex management model in Southeast Asia. However, the effects of BCF on phosphorus (P) availability and associated soil microbial communities remain poorly understood. In this study, we compared the soil properties, P fractions, phosphatase activities, and bacterial community compositions in the surface soil (0-20 cm) of a typical BCF system under different grazing densities [represented as distances of 5, 15, 25, 35, and > 60 m (control site) from the henhouse, respectively]. We observed that total P (Pt) accumulation was more rapid than that of SOC and TN with increasing grazing density. Labile and moderately labile P dominated soil P accumulation under BCF. Resin-Pi, NaHCO3-Pi, and 1 M HCl-Pi increased by 100-233%, 83-183%, and 414-1,314%, respectively, compared with the control. The ratio of labile and moderately labile organic P to the Pt content decreased significantly with increasing grazing density from 38.54% (control) to 17.65% (5 m site). Soil phosphatase activity increased with increasing grazing density, suggesting that BCF effectively promoted the mineralization of soil Po. Inorganic P (Resin-Pi, NaHCO3-Pi, and 1 M HCl-Pi) was positively correlated with Flavobacterium, Pseudomonas, and Arthrobacter but negatively correlated with Burkholderia; this highlights the different functional bacteria involved in P cycling. We conclude that BCF generally increased soil P availability and supply capacity, and the changes in P forms were closely related to changes in soil bacterial community composition. The highly labile P and low C : P ratio under high grazing density conditions may cause soil nutrient imbalance and P leaching.