Effect of long-term fertilization on the content and turnover of soil microbial biomass P

Long-term application of chemical P fertilizer and organic fertilizer could increase SMB-P content, especially organic fertilizer, but application of single chemical N fertilizer could decrease SMB-P content. During maize growth periods, SMB-P increased first and then decreased, and showed a peak value at the metaphase or anaphase of maize growth periods. After one growing season, SMB-P content was lower than that before fertilization. Long-term fertilization could increase the P supply amount by SMB-P, there was a significant correlation between P supplying amount by SMB-P with maize yield and P uptake. P supplying amount of SMB-P took up 11.79%~34.46% of plant phosphorus uptake amount. Turnover time of SMB-P was 0.68~1.61 year in different fertilization treatments and fertilizer application could extend SMB-P turnover time, but single application of chemical nitrogen fertilizers could accelerate its turnover. There was a significant correlation between SMB-P and soil P fertility.