Changes in the content of humus in gray forest soils under long-term fertilization

Resumo

The effect of different fertilizing systems on the content of humus in gray forest soils of the Opolie region has been studied during three cycles of eightand seven-course crop rotations. At the application of phosphorus–potassium fertilizers and without fertilization, the content of humus in the plow layer has decreased by 0.02% annually in the first rotation cycle and by 0.011% in the second and third cycles. In the first cycle, the addition of 1 t of litter manure and 1 kg of nitrogen increased the humus content by 55 and 9.8 kg, respectively; in the second and third cycles, the humus increment due to the organic and mineral fertilizers decreased by 2–3 times.