Effect of P reduction on phoD-harboring bacteria community in solar greenhouse soil

Abstract: In the greenhouse vegetable cultivation (GVP), long-term heavy application of phosphorus (P) fertilizer is common, while the P reservoir resources are limited. This study aims to investigate the effects of P reduction on cucumber plant growth, soil P fractions and phoD-harboring bacterial community in the greenhouse P-rich soil. The three experimental treatments were conventional nitrogen (N), P and potassium (K) fertilizer (N1P1K1), conventional N and K fertilizer without P fertilizer (N1P0K1) and no fertilizer (N0P0K0). The results showed that there was no significant difference between N1P1K1 and N1P0K1 treatment on plant growth, yield and P uptake, and N0P0K0 was significantly lower than N1P1K1 treatment. In the state of P depletion (N0P0K0, N1P0K1), the main P sources were Resin-Pi, NaHCO3-Pi, NaHCO3-Po and NaOH-Pi. The contents of NaOH-Po and CHCl-Po in N1P0K1 treatment increased significantly. Without P fertilizer, ALP activity, phoD gene abundance and bacterial community diversity were significantly increased. The abundance of Ensifer in N0P0K0 and N1P0K1 treatments was 8 and 10.58 times higher than that of N1P1K1, respectively. In addition, TP and AN were the main factors driving the change of phoD bacterial community, Shinella, Ensifer and Bradyrhizobium were the main factors driving the change of soil P fractions, NaHCO3-Pi and NaOH-Pi were the main factors affecting crop yield. In conclusion, reducing the application of P fertilizer will increase the diversity of phoD gene bacterial community and promote organic P mineralization, thus maintaining the optimal crop yield.