Phosphorus Availability and Balance with Long-Term Sewage Sludge and Nitrogen Fertilization in Chernozem Soil under Maize Monoculture.

A continuous long-term field experiment with maize monoculture was conducted to evaluate the P availability and balance, DM yield, P uptake, and P sorption parameters in chernozem soil after 27 years. A total of 2 doses of nitrogen (120 and 240 kg ha) were applied as mineral nitrogen (N and N) and sewage sludge (SS and SS) and compared with unfertilized control (Con). The aboveground biomass (DM) yields significantly increased in the order of Con < SS < SS < N < N treatments and the maximum P uptake was recorded for both N and SS (25.1 kg P ha) according to the nutrient application gradient. The N and N treatments positively influenced the DM yield but negatively influenced the P balance (-648 and -678 kg P ha 27 years), gradually bringing a risk of P deficiency in the soil. On the other hand, applications of SS and SS positively influenced the P availability and pseudototal (P) content in the soil, which resulted in a buildup of legacy P or an increase in P saturation greater than the environmental threshold value. Aluminum was found to be a major controlling sorption factor for P in our chernozem soil.