Effect of fertilization system and tillage on weed infestation of sugar beet sowings in short crop rotations

Abstract

Purpose. The present study was carried out to investigate the effect of soil tillage method and fertilization system on the degree of weed infestation of sugar beet sowings in different crop rotation units under the conditions of the Left-Bank Forest-Steppe of Ukraine.Methods. Field, statistical.Results. The study was carried out in the area of insufficient soil moisture of the Left Bank Forest-Steppe of Ukraine on the slightly saline chernozem in a long-term stationary experiment in the following short crop rotations: crop rotation system esparcet + Festuca pratensis and grain-hoed crop rotation. Fertilization for the experiment was organo-mineral, both in crop rotation and under sugar beet. The research results show that weed infestation was affected by all experimental factors, i.e. by tillage method, fertilization system, and crop rotation unit. Thus, in sugar beet sowings in the crop rotation unit with esparcet and fescue grass, at the time of leaf closure in rows, 33.4 plants/m2 of weeds were recordedin the unfertilized treatment, while in the fertilized treatment their number ranged between 16.7 and 24.0 plants/m2. In the grain − hoed crops rotation 56.0 plants/m2 of weeds were found in the treatment with ploughing and 69.6 plants/m2 in the treatment with combined tillage. The practice of the organic-mineral fertilization system in the crop rotation unit with bare fallow reduced the number of weeds to 16.7−23.6 plants/m2 with ploughing and to 37.0−49.0 plants/m2 with combined tillage.Conclusions. Weed infestation in the crop rotatory system on the background of organic-mineral fertilization was comparable with the grain − hoed crops rotation. In the grain − hoed crops rotation, segetal weeds were dominant in combined tillage. The use of fertilizers markedly reduces weed infestation. The most intensive weed infestation was observed in the treatment with straw + N140P90K90, 49.0 plants/m2 in combined tillage and 23.6 plants/m2 in ploughing. Monocotyledonous weeds were represented by Setaria glauca that was dominant in combined tillage, with 3.0−5.7 plants/m2 of weeds on the background of organo-mineral fertilization. In the treatments with organic-mineral fertilizers, of the dicotyledons, Amaranthus retroflexus was the dominant weed species, both in ploughing (7.0−16.6 plants/m2) and combined tillage treatments (19.6−23.6 plants/m2).