Zhang, Yin-jie;Gao, Wei;Luan, Hao-an;Tang, Ji-wei;Li, Ruo-nan;Li, Ming-yue;Zhang, Huai-zhi;Huang, Shao-wen

Tianjin Acad Agr Sci, Inst Agr Resources & Environm, Tianjin 300192, Peoples R China;Chinese Acad Agr Sci, Inst Agr Resources & Reg Planning, Key Lab Plant Nutr & Fertilizer, Minist Agr & Rural Affairs, Beijing 100081, Peoples R China;Hebei Acad Agr & Forestry Sci, Inst Agr Resources & Environm, Shijiazhuang 050051, Peoples R China;Hebei Agr Univ, Coll Forestry, Baoding 071000, Peoples R China

organic substitution management;soil P pools;phosphatase activity;microbial community;soil C;P;PLS-PM

Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus (P) in agricultural production. However, few studies have comprehensively evaluated the effects of long -term organic substitution on soil P availability and microbial activity in greenhouse vegetable fields. A 10-year (2009-2019) field experiment was carried out to investigate the impacts of organic fertilizer substitution on soil P pools, phosphatase activities and the microbial community, and identify factors that regulate these soil P transformation characteristics. Four treatments included 100% chemical N fertilizer (4CN), 50% substitution of chemical N by manure (2CN+2MN), straw (2CN+2SN), and combined manure with straw (2CN+1MN+1SN). Compared with the 4CN treatment, organic substitution treatments increased celery and tomato yields by 6.9-13.8% and 8.6-18.1%, respectively, with the highest yields being in the 2CN+1MN+1SN treatment. After 10 years of fertilization, organic substitution treatments reduced total P and inorganic P accumulation, increased the concentrations of available P, organic P, and microbial biomass P, and promoted phosphatase activities (alkaline and acid phosphomonoesterase, phosphodiesterase, and phytase) and microbial growth in comparison with the 4CN treatment. Further, organic substitution treatments significantly increased soil C/P, and the partial least squares path model (PLS-PM) revealed that the soil C/P ratio directly and significantly affected phosphatase activities and the microbial biomass and positively influenced soil P pools and vegetable yield. Partial least squares (PLS) regression demonstrated that arbuscular mycorrhizal fungi positively affected phosphatase activities. Our results suggest that organic fertilizer substitution can promote soil P transformation and availability. Combining manure with straw was more effective than applying these materials separately for developing sustainable P management practices.