Oilseed Rape Yield Performance in the Clearfield® System under Varying Management Intensities

Oilseed rape production is under pressure due to a limited availability of herbicides. Therefore, the performance in terms of management intensity (MI) and herbicide strategy (HS) and the involved yield formation was evaluated in a two-year Clearfield® oilseed rape field experiment. Furthermore, weed density and weed composition were also investigated. The variants of MI were standard sowing density (StS; seed rate: 50 seeds m−2, primary tillage: plow, row width: 12 cm), reduced sowing density (RD; seed rate: 25 seeds m−2, primary tillage: plow, row width: 50 cm), and strip-till (ST; seed rate: 25 seeds m−2, primary tillage: strip tillage, row width: 50 cm). The variants of HS were preemergence strategy (PES; application of dimethachlor, napropamide, clomazone in preemergence and application of prapaquizafop in postemergence) and Clearfield® strategy (CLS; application of imazamox, quinmerac in preemergence, no postemergence herbicide application). In the first year of the trial, there were no interactions between the factors in terms of grain yield. Grain yield in StS was 3.85 t and 5.2% significantly lower than in ST, and the value of RD was not significantly different from StS and ST. Grain yield in CLS was 3.7 t and 2.7% lower than in PES. In the second year of the trial, the grain yield in ST CLS was significantly lower, and there were no significant differences between the other variants. Higher weed emergence was observed in CLS RD (2.7 to 4 times higher weed density compared to PES RD) and CLS ST (2.8 to 4.5 times higher weed density compared to PES ST). No significant differences existed between StS PES and StS CLS in both trial years. The Clearfield® system offers significant advantages in the control of cruciferous weeds. Although these did not occur on the trial fields, the Clearfield® system in this study showed to be an alternative to the more common pre-emergence system, especially with regard to the parameter grain yield.

REVIEW OF THE INFLUENCE OF CROP ROTATION AND PRIMARY TILLAGE OPERATIONS ON WEED SEED BANK

In this study, we reviewed weed seed bank dynamic and main agriculture operations to come up with the weed seed management modeling designed to increase crop productivity by removing weed competition. Weed contributing with 10% loss of total global grain production. Weed seed bank regulate by five demographic processes seedling recruitment and survival, seed production, dispersal and seed survival in soil. The main agriculture operations that interference with weed seed bank are crop rotation and primary tillage. Tillage systems affect weed emergence, management, and seed production; therefore, changing tillage practices changes the composition, vertical distribution, and density of weed seed bank in agricultural soils. Weed species vary in their response to various crop rotations, due to the variability of weed-crop competition in their relative capacity to capture growth–limiting resources. Crop rotations affect weed emergence, management, composition, and density of weed seed bank. Finally, the study suggests elevating crop competitiveness against weeds, through a combination of crop rotation and reduce_ zero tillage, has strong potential to reduce weed-induced yield losses in crop.

Influence of primary tillage on agrochemical indicators of soil fertility

The influence of primary tillage practices (plowing, subsurface tillage, surface tillage, direct sowing (No-till)) on the indicators of soil fertility of typical chernozem in Kursk Region on peas was studied. It was found that with the minimization of tillage humus content in the soil increased, especially in the upper 0-10 cm layer. Acidification of arable soil layer was noted when plowing was used. The content of mobile phosphorus, as well as the degree of its mobility, significantly increased with boardless tillage methods in comparison with moldboard plowing. The maximum amount of exchangeable potassium and the degree of its mobility were in case of direct sowing. The highest level of mineral nitrogen in the layer of 0-20 cm was formed in case of plowing, and its minimum level was formed in case of direct sowing. When tillage was minimized, the topsoil was differentiated by the content of mobile forms of copper, zinc and manganese. In a layer of 0-10 cm, combined tillage, surface tillage and direct sowing increased the content of mobile trace elements compared to a layer of 10-20 cm. When plowing was used as a primary tillage method, the content of mobile copper, zinc and manganese was higher in the layer of 10-20 cm.

Content of macronutrients in the plant residues of winter wheat while minimizing primary tillage

As a result of the research, the influence of primary tillage practices (plowing, combined tillage, surface tillage, direct sowing) was studied on the accumulation of nitrogen, phosphorus and potassium in plant residues in the soil, in the straw and grain of winter wheat, under the conditions of chernozem soils of Kursk Region. The balance of macronutrients coming from plant residues was calculated. It was found that in the spring period in the soil layer 0-20 cm under winter wheat there was more undecayed plant residues when subsoil practices of primary tillage were used. At the same time, as the depth of tillage decreased, a large mass of plant residues was concentrated in the upper 0-10 cm layer of the soil. By the harvest period, there was an increase in the amount of plant residues in the soil by 2.96-4.62 t/ha. At the same time, the highest indicators were observed in case of plowing and direct sowing 4.62 and 4.53 t/ha, respectively. The highest reserves of nitrogen and potassium in undecayed plant residues under winter wheat in the soil were found when using direct sowing (36.0 kg/ha), those of phosphorus when plowing (10.5 kg/ha) was used in the soil layer of 010 cm. The highest mass of winter wheat straw was formed against the background of plowing (6.2 t/ha), while the content of phosphorus and potassium in it was the highest (0.26% and 1.10%, respectively). The highest yield of winter wheat grain was formed against the background of plowing (4.40 t/ha), the lowest yield was with direct sowing (3.26 t/ha). Without the use of mineral fertilizers, a negative balance of macronutrients was formed.

Efficiency of cultivation technologies for spring wheat with different levels of intensity on chernozem soils of Kursk Region

The paper presents the results of research on the efficiency of technologies for cultivating spring wheat at various levels of intensity (extensive, intensive, resource-saving) under the conditions of chernozem soils of Kursk Region. It was found that higher reserves of available moisture and nitrate nitrogen in the arable layer of the soil before sowing spring wheat were provided by technologies with moldboard plowing. Replacing plowing with subsurface methods of tillage led to a decrease in the available moisture and nitrate nitrogen reserves in the soil for all fertilizer systems. The lowest weediness of spring wheat was observed when it was cultivated using technologies with moldboard plowing 52.3-58.3 PCs/m2, depending on the fertilizer system. The replacement of plowing with subsurface and surface tillage increased the weediness of crops to 61.7 and 73.7 PCs / m2, respectively. Application of mineral fertilizers had almost no significant effect on the number of weeds in spring wheat. The highest yield of spring wheat in all the years of studies (4,27 t/ha) was obtained in the intensive cultivation technology involving plowing at 20-22 cm, fertilization at a rate of N60Р60К60, treatment of crops with pesticides based on economic threshold of harmfulness. Yield of spring wheat, cultivated by resource-saving technologies with organic-mineral system of fertilization 0.86-4.25 t/ha depending on the methods of primary tillage. Moldboard plowing of the soil against the background of the organic-mineral fertilizer system increased the yield of spring wheat by 0.18 t/ha in comparison with subsurface tillage and by 0.39 t/ha in comparison with surface tillage. However, due to higher production costs, the best economic indicators were obtained when spring wheat was cultivated using resourcesaving technologies with an organic-mineral fertilizer system and non-moldboard methods of primary tillage.

QUALITY OF GARDEN STRAWBERRY FRUIT GROWN UNDER CONDITIONS OF TECHNOGENIC POLLUTION

The quality of fruit of garden strawberries grown on technogenically contaminated soils has been assessed. The highest level of copper and zinc in the fruit was recorded after broadcasting the recommended quantity of the fertiliser N90P60K30. Introduction of the sorbent ameliorant GREENODIN GRAY reduced the content of copper and zinc in the strawberries by 39 and 59% respectively. Researching the early-ripening strawberry cultivars Olviya and Rozana Kyivska has revealed varietal differences in the fruit’s trace element composition. Thus, it can be considered that selection of the proper cultivar is another effective method of obtaining environmentally safe products. Both strawberry cultivars under study were characterised by intense translocation of Cu and Zn into fruit. However, the Rozana Kyivska fruit contained 3 times more copper than the cultivar Olviya did. The zinc level, too, was higher in the Rozana Kyivska fruit (by 1.5 times). When introducing the recommended quantity of the fertiliser N90P60K30, the following criteria for the potential storability and transportability of the Olviya berries were recorded: resistance to phytopathogens, dense consistency of a berry, and the dry matter content 10.08%. As a result, the Olviya berries had the longest shelf life – 7 days, when stored in cooling chambers at 0.5°С and relative air humidity 90%. The sugar-acid index in these samples had the maximum value 6.9%, but the amount of vitamin C was at a minimum. This research has become the basis for practical application of a technology of growing strawberries of the cultivar Olviya. The technology involves broadcasting the fertiliser N90P60K30 together with the sorbent ameliorant GREENODIN GRAY (500 kg/ha) during the primary tillage, and introduction of N45P30K15 with irrigation water. The resulting Olviya berries are resistant to diseases and phytopathogenic damage during storage, have high nutritional value, and are less likely to accumulate ecotoxicants. The yield of berries in the first year of using the plantation was 6,200–6,500kg/ha. The content of nitrates and heavy metals in the berries did not exceed the maximum permissible concentration.