Effects of Long-Term Chemical and Organic Fertilizer Application on Soil Phosphorus Fractions in Lei Bamboo Plantations

Abstract

Phosphorus (P) is a key nutrient in forest ecosystems in subtropical regions. However, the effects of the long-term application of organic amendments on P availability are poorly understood. Here, we compared the soil P fractions and associated soil properties in southern Chinese Lei bamboo plantations using both an intensive management system (IMS) and a traditional management system (TMS). The results show that the IMS significantly (p < 0.05) increased the soil total organic carbon (C), soil ammonium N (NH4-N), total P, and available potassium content; microbial biomass C and P content; P activation coefficient, and soil C:P ratios, while significantly (p < 0.05) decreasing pH and microbial C:P. The labile-P-to-total-phosphorus-content ratio increased significantly in the IMS (46%) compared with that in the TMS (32%). The selected soil properties (except nitrate [NO3−N]) were significantly related to soil P fractions (except for concentrated HCl-extracted organic P). The IMS had a higher C:P ratio and labile P content than the TMS, suggesting that the IMS could promote soil P transformation and availability. Overall, the IMS increased soil P availability and supply capacity, and the changes in P forms could be a risk factor for P loss.