Научный журнал

The research was conducted in a long-term experiment with NPK fertilizers applied on tea plants in the humid subtropics of Russia. It was found that when removing 13-23 kg of P2O5/ha per year with a yield of 44-76 kg/ha, the annual application of 60, 120, 180 kg of P2O5/ha led to a significant accumulation of phosphorus in brown forest acid soils (Dystric Cambisols, SSSA). Over the past 26 years, its total content has increased by 2-3/1,5-2,5 (up to 1950-3200/1650-2700 mg/kg, in 0-20/20-40 cm) due to mineral compounds with a stable organic content (550-650 mg/kg). The accumulation of Al-P was predominant, while the proportion of Ca-P decreased. The content of mobile phosphorus increased by 6-14 times (from 6-10 to 20-35% of total phosphorus). The dose of P60 maintained the optimal level for tea plants (400-600 mg/kg); against the background of P120,180, it was excessively high (up to 1100-1200/780-850 mg/kg). The content of easily mobile phosphates increased by 3-15 times, accounting for 0.5-1% of mobile phosphorus (while loosely bound phosphates ac counted for 10-15%). Agrogenic acidification of the soil under tea plants significantly affected the change in phosphate parameters. Doses of P120,180 with a low utilization rate and a high proficit, which do not lead to an increase in yield and cause soil overphosphating, are impractical in a multi-year regime. The phosphorus accumulated by the soils is a reserve potentially available for tea plants, which makes it possible to minimize fertilizers application in the future.