The phosphate regime of gray forest soil and the efficiency of phosphate fertilizer

In long-term field experiments, it was found that, the interaction between phosphoric fertilizer and soil results in the preservation of half of the added phosphorus in the plow horizon as mineral phosphate. It remains available to plants for a long time and provides for a high aftereffect of fertilizer as efficient as the direct effect. The use of fertilizer phosphorus by plants is inversely related to the initial content of available phosphates in the soil and directly related to the nitrogen supply. It increases when the soil phosphate content increases up to the optimal level (its lower limit is 10-12 mg/100 g in a 0.2 N HCl extract).