engleski

Investigation of efficacy of some new herbicides and their combination

During the growth season of 1994-1996 through exact microtrials on the field of the Osijek Agricultural Institute at Osijek, Eastern Croatia, were investigated 14 herbicides and their combinations by soybean. The main purpose of this study was evaluated the most effective herbicide against present weed flora as well as their selectivity and their indirect effect on the soybean yields comparing with three controls (check weedy, handing weeding, cultivation weeding). Treatments were arranged as randomized complete block design with four repetitions. The soybean cultivar (cv) Lika was used in these trials. According phytotoxicity, the most of herbicide treatments tested were fully selective to soybean plants within 30 days after application of preparations. But within 15 days after the application, by visually observations, some of treatments gave a slight injury to soybean crop. Weed flora in the trials on the check weedy consisted of 18 species among which the most dominant in green mass were Echinochloa crus galli (L.) PB of monocotyledon and Abutilon theophrasti Med., Ambrosia artemisiifolia L. (=A.elatior L.), Amaranthus retroflexus L., Chenopodium album L; Chenopodium hybridum L., Cirsium arvense (L.) Scop., Carduus acanthoides L; and Polygonum lapathifolium L. of dicotyledons. Most of these weed species, collectively make on aggressive complex of economically important weeds for soybean crops in Croatia. All tested herbicides and their combinations reduced considerably the weed density in soybean in comparison with the untreated plot throughout three years investigations. Particularly good results were achieved in average three years for monocotyledon weed species by combination of herbicide Treflan+(Bravo+Prohelan) applied pre sowing + pre emergence in doses 1,5+(5+1) l/ha. The combination of herbicide Treflan + Sencor have been had the best effectiveness for both weed species (monocotyledon and dicotyledon) in doses 1,5+0,5 l/ha applied pre sowing and pre emergence. Herbicide Dynamo in dose 100 g/ha applied post emergence also good controlled both weed species. All examined herbicides and their combinations caused an increase of the yield in comparison to the untreated plots, which confirms the still well known facts that the herbicides applying in soybean is a justified measure which insures, along with other factors (as cultivar, soil type, soil moisture, rainfall and cultural practices) the increase of soybean yield.

weed flora; herbicide; phytotoxicity; coefficient of efficiency; mechanical control; grain yield

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