Reserves of available soil moisture, productivity and mass of root residues of winter wheat and post-harvest white mustard depending on cultivation, precursors and fertilizer

Abstract

Three-year (2020–2022) research at the experimental field of Bila Tserkva National Agrarian University, make it possible to calculate the economic and energy efficiency and to recommend a differentiated system of the main tillage on typical deep, low-humus medium-loamy chernozems of the Right Bank Forest-Steppe of Ukraine in a five-field specialized (cereal) crop rotation, which involves deep plowing only for row crops, and for winter wheat after both predecessors (peas and buckwheat) and post-harvest mustard for green manure cultivation with heavy disc harrows, respectively, to a depth of 8–10 and 10–12 cm with the introduction of N140P60K100 under the bread plant and N120P60K90 – after peas, and under cabbage – N80P60K80 after both predecessors. For the placement of winter wheat after legume and cereal crops and recommended agricultural measures, the cost of one ton of grain was 3.82 and 4.06 thousand hryvnias respectively, conditional net profit was 18.11 and 16.06 thousand hryvnias/ha, profitability 44.4 and 37.1 %, energy efficiency ratio 2.4 and 1.9. Reserves of available soil moisture under winter wheat are higher in the link with peas than buckwheat. The highest reserves of it in the upper, arable and meter layers in the seedling phase of the culture after both predecessors under differentiated cultivation in crop rotation. In the phase of entering the tube, this indicator is the lowest in the arable layer under differentiated, and in the meter layer - under disk cultivation in crop rotation. On the date of sowing white mustard in the row with peas, the reserves of available soil moisture in the upper layer differed insignificantly according to tillage options, and in arable land they are the highest under shelf-disc tillage. In the meter layer, this indicator did not undergo significant deviations from the control, although it increased compared to it by 1.2–2.5 mm. For the predecessor of buckwheat, the content of soil moisture in the investigated layers (0–10, 0–30 and 0–100 cm) on the date of sowing white mustard increased significantly under differentiated and decreased significantly under disk tillage. In the upper layer of the soil, this indicator is slightly higher in the link with peas (by 0.5 mm), in the arable one with buckwheat (by 2.6 mm), and in the meter layer – it is almost the same for both predecessors. The yield of winter wheat is 0.59 t/ha higher in the link with peas than with buckwheat. After both predecessors, it is the largest under differentiated cultivation of fertilized and unfertilized plots. With chisel-disk and disk processing, this indicator is significantly reduced. Only on unfertilized plots under shelf-disk and disk tillage, the yield of green mass of white mustard is higher in the link with peas than with buckwheat, in the remaining variants of the experiment, the preference is for the grain predecessor. This indicator in the link with peas decreased, for all tillage options, compared to the control, but significantly only for disc tillage. In the link with buckwheat, its significant decrease is observed under disc cultivation and a significant increase under differentiated cultivation of fertilized areas. The dry mass of root residues of winter wheat is significantly lower for chisel-disc and disc than for shelf-disc treatments in both predecessors. Under differentiated processing, this indicator increased, compared to the control, but insignificantly. The mass of the dry root of white mustard in the link with leguminous crop is less for all tillage options, compared to the control, but it is significantly (by 0.19–0.25 t/ha) less for discing the soil. With an increase in fertilizer application rates, the dry weight of the root residues of the studied crops grows more slowly than the yield. At the same time, a slower growth of both above-ground and underground mass of both agrophytocenoses was established for placing them after the leguminous than for the cereal predecessor. Calculations of economic and energy efficiency give reason to recommend a differentiated system of the main soil cultivation on typical deep, low-humus, medium-loam chernozems of the Right Bank Forest Steppe of Ukraine in a five-field specialized (cereal) crop rotation, which involves deep plowing only for row crops, and for winter wheat after both predecessors (peas and buckwheat) and post-harvest mustard for green manure tillage with heavy disc harrows, respectively, to a depth of 8–10 and 10–12 cm with application of N140P60K100 under the bread plant after 1 buckwheat and N120P60K90 – after peas, and under cabbage – N80P60K80 after both predecessors. For placing winter wheat after leguminous and cereal crops and recommended agromeasures, the cost price of one ton of grain was UAH 3.82 and 4.06 thousand respectively, conditional net profit was UAH 18.11 and 16.06 thousand/ha, profitability 44.4 and 37.1 %, energy efficiency ratio 2.4 and 1.9. Key words: soil, cultivation, productivity, fertilizers, predecessors, cultures, root residues, crop rotation.