The weed pollution in Miscanthus giganteus

Abstract

Goal. Is to determine the species composition of weeds in Miscanthus giganteus plantings, their impact on biomass productivity and the development of an effective protection system. Methods. Field experiments, laboratory agrochemical studies, mathematical and statistical — to evaluate the reliability of the obtained data. Results. At the beginning of the first year of vegetation in the miscanthus crops, the type of weed was mixed, with a large predominance of annual monocotyledonous species 91.1—93.6%. But in the second (70.1—85.3%) and the third (51.1—79.8%) years of vegetation, dicotyledonous species prevailed, while in the fourth, the monocotyledonous species (55.6—64.8%) had a slight advantage. In the first year of vegetation the weed was quite high and amounted to 1156 p./m2, in the second year — 873 p./m2, it decreased to 380—386 p./ m2. On the variants of application of herbicides for the second and next years, a decrease in the number of weeds by 41.3—64.5% compared with the weed pollution control and depending on the year of vegetation was observed. In the conditions of co-vegetation of weed plants with the weeds, the largest mass was formed by the Chenopodium album L. (930 g/m2 in the first year and 93 g/ m2 in the fourth year), Amaranthus retroflexus L. (455 g/ m2 and 60.6 g/ m2), Artemisia annua L. (280 g/m2 and 29.1 g/m2) and annual monocotyledonous Echinochloa crus-galli (L.) Pal. Beauv. (225 g/ m2 and 17 g/ m2) and Setaria glauca (L.) Pal. Beauv (360 g/ m2 and 15.4 g/ m2). Weed pollution control on miscanthus crops helped to increase the biomass yield in the first year of vegetation to 2.6—2.7 t/ha of wet weight, to the fourth — up to 36.3—37.4 t/ ha. In the Weed pollution control, only 0.5 t/ha were obtained in the first year of vegetation, while in the fourth year it was 22.1 t/ ha. Conclusions. A mixed type of weed was found on the landing of Miscanthus giganteus, with 19 species from 12 families. Application of herbicides Task Extra and Master Power weed pollution reduction by 83.3—99.2%, which made it possible to improve the conditions of growing and development of Miscanthus giganteus plants and to obtain a dry biomass yield of 20.0 t/ha for the fourth year of vegetation.