Dinamics of weed biomass development under different row cropping soybean

Tijekom 2014. i 2015. godine u gradu Vukovaru provedeno je istraživanje u usjevu soje. Pratio se utjecaj gustoće sjetve i dužine zakorovljenosti na razvoj nadzemne biomase soje i korova. Soja je bila sijana na tri različita međuredna razmaka: 25 cm, 50 cm i 70 cm. Koristio se „Aditive-removal“ model pokusa, gdje su se na jednom dijelu parcele korovi plijevili, a zatim se usjev ostavljao zakorovljenim, dok su se na drugom dijelu korovi puštali da slobodno rastu, pa onda redovito plijevili do kraja vegetacije. Sveprisutni korovi su bili oštrodlakavi šćir (Amaranthus retroflexus L.), bijela loboda (Chenopodium album L.), crvenkasti muhar (Setaria glauca (L.) Beauv.) i piramidalni sirak (Sorghum halepense (L.) Pers.). Istraživanje je pokazalo da je pri svakom međurednom razmaku sjetve bitno održavati usjev čistim od korova u prva tri tjedna od nicanja, te da pri međurednim razmacima 50 i 70 cm treba plijeviti usjev još jednom nakon toga, jer će u protivnom korovi razviti značajnu masu do žetve. Kod gustoće sjetve od 25 cm, ukoliko su korovi plijevljeni do 3. tjedna od nicanja, neće uspjeti razviti značajnu masu.During 2014. and 2015. , a soybean crop survey was conducted in the city of Vukovar. The effect of sowing density and duration of weediness on the development of aboveground soybean and weed biomass was monitored. Soybeans were seeded at three different spacing: 25 cm, 50 cm and 70 cm. An “Aditive-removal” model of experiment was used, where weeds were plowed in one part of the plot, and then the crop was left weeded, while in the other part the weeds were allowed to grow freely and then regularly weeded until the end of the vegetation. The ubiquitous weeds were the redroot pigweed (Amaranthus retroflexus L.), the white goosefoot (Chenopodium album L.), the pearl millet (Setaria glauca (L.) Beauv.) and the Johnson grass (Sorghum halepense (L.) Pers.). The study showed that at every row spacing it is important to keep the crop clear of weeds for the first three weeks after emergence, and that at row spacing of 50 and 70 cm it is necessary to plow the crop once again, otherwise the weeds will develop significant mass until harvest. At a sowing density of 25 cm, if weeds are plowed by week 3 of emergence, they will not be able to develop significant mass