The responses of soil microbial community and enzyme activities of Phoebe zhennan cultivated under different soil moisture conditions to phosphorus addition

Abstract

The importance of conservation and ecological restoration of the rare and economically important tree Phoebe zhennan is increasingly recognized. To this purpose, phosphorus (P) addition has been proposed to improve soil biological attributes and face the anticipated drought under climate change, though few studies have investigated its effect on the interaction between the soil microorganisms and plant host, as well as on ecosystem productivity. We investigated the effect of P addition on soil chemical properties, microbial communities, and enzyme activities in a soil planted with P. zhennan under two levels of water treatments (optimum water and drought treatments). P additions had no significant effect on microbial communities, dissolved organic nitrogen (DON), pH and soil moisture (SM), though the available P (aP) increased. Compared with no P treatment, alkaline phosphate and β-fructofuranosidase activities increased with P additions in the drought treatment. Drought decreased the total phospholipid-derived fatty acids (PLFAs), arbuscular mycorrhiza fungi (AMF), and fungi PLFAs compared to the well-watered. These findings indicated that P additions does not ameliorate the impact of drought on soil microbial communities and enzyme activities, except alkaline phosphate and β-fructofuranosidase, and P may not be responsible for regulating biochemical processes essential for maintaining the fertility of soil planted with P. zhennan under drought conditions. It is hypothesized that the lack of effects of P addition on the majority of the microbial properties could be due to the soil mechanism employed by P. zhennan to tolerate harsh conditions.