[Humus state of the soil while involving different fertilizer systems and cultivation in a crop rotation]

English. Outlined are results of studying the soil humus content in a two-factor stationary experiment (1995-1998) involving different fertilizing and soil cultivation systems in a crop rotation in the long run. As the factor A, the experiment involved four fertilizing systems, in particular 1) no fertilizing; 2) mineral system for planned crop yield (N69.4P34.8); 3) organomineral system (10 t/ha of manure + N30.7P17.1); 4) organomineral increased system(20 t/ha of manure + N26.3 P13.0). As the factor B, the experiment included the following soil cultivation systems: 1) variable-depth real tillage (disk tillage for 8-10 cm under winter wheat after maize, tillage for 28-30 cm under maize and 20-22 cm under the rest of crops); 2) variable-depth non-moldboard (the depth like in the variant 1); 3) surface tillage under all the crops (for 8-10 сm for winter crops and 10-12 for spring crops); 4) combined (under winter wheat after a fallow-occupying crop tillage for 20-22 cm, after maize disk tillage for 8-10 m, under the remaining crops – non-moldboard tillage like in the variant 2). The crop rotation scheme was as follows: 1- sown fallow (oat + vetch or oat + oil radish); 2 – winter wheat; 3 – winter barley; 4 – maize for green mass; 5 – winter wheat; 6 – spring barley; 7 – oil flax. It was found out that organomineral fertilizers only contributed to soil humus accumulation. Hence, raising a manure rate from 10 to 20 tonnes per hectare of the crop rotation area did not make positive effect on the humus accumulation. Yet while surface tillage was used for the long term, the humus content increased, especially in a 10-20 cm layer. Soil cultivation of the kind also enhanced soil profile differentiation according to the humus content: it raised in the upper part and decreased in the lower part as compared to the real tillage.

Ukrainian. Викладено результати дослідження умісту гумусу в грунті в 2-факторному стаціонарному досліді за тривалого застосування різних систем удобрення й обробітку грунту в сівозміні.