Effect of long-term fertilization on the content, fractional composition, and budget of humus in soddy-podzolic soils of the North-Eastern Europe
The efficiency of organic fertilizers and their combinations with mineral fertilizers in forage crop rotation on medium-cultivated sandy loamy soddy-podzolic soil was studied in a long-term stationary field experiment. It was found that the combined application of organic (40 t/ha every 3-4 years) and NPK (annually at the rates calculated to compensate the removal of nutrients) fertilizers was the optimum method. In this case, the soil fertility was improved, the reserves of humus increased, its quality improved, and the yield and nutritional value of crop increased.