The effect of direct sowing on the productivity of summer rape

Direct sowing or no-till sowing has become a widespread tillage in many countries around the world as it is very beneficial from an agronomic, ecological and economic point of view. The aim of the study was to evaluate the effect of direct sowing and fertilization norms on the productivity of summer rape sowings. Field trials with summer oilseed rape 'Heros' were carried out on sod stagnogley soil (55 ° 88 'N, 26 ° 53' E). Soil agrochemical parameters: pHKCl 5.8, organic matter content in soil – 3.8 %, phosphorus content – 122 mg kgE−1 P2O5 and potassium content – 181 mg kgE−1 K2O. Summer rape sowings were conducted by using the following variants: seed sowing norms: 7 and 10 kg haE−1; in the norms of nitrogen fertilizers: N0, N100 and N180; herbicide Fuego top rates: 0 and 2 L haE−1. The placement of the variants in the three-factor trial was randomized in four replicates. Precrop was winter wheat. Weed inventory was carried out by weight and by species during the vegetation period of summer oilseed rape. The sowing density, yield structure and yield were recorded for each experimental variant in all replicates at the end of the vegetation, and the yield quality was determined, i.e., 1000 seed mass, seed bulk density, oil content and oil extraction per hectare. In the studied variants, the number of seeds in pods changed on average within 20–25 number limits. The bulk density of the seeds was 62 kg hLE−1 with an average weight of 3.2 grams per 1000 seeds. The oil content of the seed in the control variants averaged to 46.2%, regardless of the sowing rate, but the nitrogen fertilizer rates had a negative effect on the oil content and reduced it by an average of 2-3%. The seed yield in the control variants averaged to 0.84 t haE−1. Nitrogen fertilizer norms promoted higher seed yield and at N100 kg ha-1 it was 1.11 t haE−1, but at N180 kg haE−1 – 1.27 t haE−1 with average oil yield of 0.39, 0.51 and 0.59 t haE−1, respectively.