Soil Tillage and Fertilization Systems as Determinants of Crop Productivity and Agroecological Properties of Typical Chernozem

Long-term studies have shown that systematic use of organic and organo-mineral fertilization systems improves the nutrient regime of typical chernozem, resulting in differentiated distribution of phosphorus and potassium within the plow layer under prolonged minimal tillage. A tendency toward increased soil bulk density was observed in the 20 - 40 cm and 40 - 60 cm layers under continuous shallow loosening, in which density exceeded the upper limit of the optimal range (1.0 - 1.3 g/cm³). Incorporation of manure and mineral fertilizers, compared with surface loosening, enables an additional annual sequestration of 0.3 - 0.4 t/ha of carbon - equivalent to 1.2 - 1.6 t of carbon dioxide. Based on the 20-year mean and maximum yields of silage maize, shallow loosening yielded 10% less biomass than combined tillage across fertilization variants. Winter wheat after silage maize was only weakly affected by tillage method; under reduced production costs, shallow loosening is advisable. In favorable years, the straw-to-grain ratio in wheat increased significantly. Sugar beet showed a compensatory effect of fertilization that mitigated the negative impact of minimal tillage. Under near-optimal conditions, the ratio of main to by-product increased from 0.5 to 1.0. Under favorable hydrothermal conditions and natural soil fertility, as well as under long-term application of organic fertilization systems for soybean, minimal tillage proved suitable, whereas organo-mineral systems required combined tillage. Declines in long-term average productivity of soybean, spring barley, and pea under minimal tillage compared with combined tillage were observed only under specific fertilization variants. Under optimal moisture and temperature, the grain-to-straw ratio in soybean decreased. For winter wheat after pea, shallow loosening showed a tendency to outperform combined tillage, with a significantly higher grain-to-straw ratio in favorable conditions. Maize for grain responded more strongly to combined tillage, which exceeded shallow loosening by 6 - 10% depending on fertilization. In favorable conditions, the stalk-to-grain ratio increased markedly, especially under fertilized treatments. Among all studied crops, sugar beet productivity fluctuated the most in response to annual weather variation, while winter wheat after pea and grain maize fluctuated less. In terms of long-term average crop rotation productivity, minimal tillage was 4 - 8% lower than combined tillage at a 5% significance level. For livestock-oriented production systems with manure application, combined tillage is recommended. For crop-oriented systems, surface loosening is economically justified for all crops.