Dosage effects of organic manure on bacterial community assemblage and phosphorus transformation profiles in greenhouse soil

A field experiment in a greenhouse farming with manure application instead of chemical phosphate fertilizers was established, including five treatments: A Control with conventional fertilization and chemical phosphate fertilizers substitution treatments using manure as the sole P resource at the amount of 25% (0.25Po), 50% (0.50Po), 75% (0.75Po), and 100% (1.00Po) of the Control. Except 1.00Po, all the treatments applied with manure harbored similar level of available P (AP) as Control. Most of the bacterial taxa involved in P transformation were enriched in manure treatments. 0.25Po and 0.50Po treatments significantly enhanced bacterial inorganic P (Pi) dissolution capacity, while 0.25 Po decreased bacterial organic P (Po) mineralization capacity. In contrast, 0.75Po and 1.00Po treatments significantly decreased bacterial Pi dissolution capacity and increased Po mineralization capacity. Further analysis revealed that the changes of bacterial community was significantly correlated with soil pH, total carbon (TC), total nitrogen (TN), and AP. These results revealed the quantitative effect of the impact of manure on soil P availability and microbial P transformation capacity and emphasized that appropriate dosage of organic manure is important in practical production.