The influence of mineral fertilizers on the background of liming on the fractional composition of the humus balance in soddy-podzolic soil of the north

Abstract

In the long-term field stationary experiment on sod-podzolic weakly cultivated soil, studies were conducted on the effect of lime (aftereffect of 1983) and annual application of mineral fertilizers calculated from the removal of NPK by the planned harvest of perennial grasses on the change in soil properties, including humus. Result As a result of researches it is established that mineral fertilizers and meliorants exerted considerable influence on change of humus balance, and also its group and fractional structure. Our studies have shown that the reserves of humus in the soil of the experimental site amounted to 41.6-46.8 t/ha. The volumes of root crop residues entering the soil according to the variants of the experiment were 3,8-5,7 t/ha, the greatest number of them was obtained in the variants of NPK application for limed soil - 5,5-5,7 t/ha and the yield of perennial grasses for these variants was the highest (4,7-5,0 t/ha SV). The use of lime and mineral fertilizers in the humus increased the amount of humic acids to 21.5-25.3%, in the version without fertilizers - 17.8%. Especially increased (from 2.1 to 5.8%) fraction of ha-2 associated with potassium and magnesium. The most aggressive fraction of FC 1A fulvic acids significantly decreased. These changes in the labile part of humus allowed to change the type of humus - from fulvate type (SGC:SFK 0.5), to HUMATE-fulvate - SGC:SFK>0.5, which improved the soil structure and plant nutrition.