Weed infestation of winter wheat in various crop rotations

Abstract

Purpose. To investigate weed distribution in winter wheat sowings as affected by crop rotation and fertilizer backgrounds.Methods. Quantitative and gravimetric.Results. Presented in the article are the experiment results on the quantitative composition of weeds and the dynamics of their accumulation in winter wheat sowings as affected by crop rotation and fertilization program. The stationary experiment was carried out on the typical leached chernozem in the zone of unstable wetting under the conditions of the Bila Tserkva Research & Breeding Station. The greatest number of weeds per 1 m2 in the period of spring tillering was observed on the unfertilized background in crop rotation (145.3) and grain – row crop rotation (146.3), that equals to 13.46 and 16.4 dt/ha, respectively. Application of fertilizers reduced the mass of both monocotyledonous and dicotyledonous weeds. Against the fertilized background, the number of weeds reduced to 27.1 and 34.0, that was in terms of weight to 6.20 and 5.77 dt/ha, respectively.Conclusions. The largest mass of weeds in winter wheat sowings was observed in unfertilized treatments. Application of fertilizers in winter wheat sowings during the spring tillering reduces the number of weeds per 1 m2 against the background of fertilizers in grain – row crop rotation to 34.0–41.0, including cereal weeds 25.6–13.0, dicotyledons 73.5–86.0 and perennial weeds 0.9–0.8. The weight of weeds against the fertilized background at the wheat harvesting amounted to 6.20 dt/ha in crop rotation and to 5.77 dt/ha in grain – row crop rotation, with the weight of cereal weeds of 1.24 and 1.10 dt/ha, respectively. The number of perennial weeds in grain – row crop rotation did not exceed 0.34 and 0.67 dt/ha and in crop rotation 0.21 dt/ha. Among the dicotyledonous weeds, the most abundant in terms of weight per 1 hectare was Amaranthus retroflehus L. with the weight ranged from 3.2 to 1.5 dt/ha. The increase in the weight of the weeds in crop rotation was due to an increase in the number of Amaranthus retroflehus L. (3.2 dt/ha) and Spergula arvensis L. (0.84 dt/ha).