Effect of Some Plant Extracts and Herbicides on Weed Control in Irrigated and Non-Irrigated Vineyards in Sulaymaniyah-Iraq

Abstract

Abstract Allelopathy, the inhibition of neighboring plant growth by certain plants, can be particularly useful if applied in a targeted way for weed management. So, this study aimed to determine the most environmentally friendly weed control technologies and identify the optimum management for lowering weed number and biomass, leading to improved grape quality and quantity. Two experiments were carried out in irrigated and non-irrigated vineyards in Sharbazher, Sulaymaniyah City, Kurdistan Region of Iraq, for two consecutive growing seasons, 2021 and 2022. The experiments were conducted at the Sitak and Maluma subdistricts of Sulaymaniyah, respectively. The effects of six aqueous plant extracts were investigated. The plants included pomegranate (Punica granatum) peels, walnut (Juglans regia) green husk, eucalyptus (Eucalyptus camaldulensis) leaves, Aleppo oak (Quercus infectoria) galls, cogon grass (Imperata cylindrica) rhizomes, nutgrass (Cyperus rotundus) tubers. Two herbicides (Glyphosate and Paraquat) were included, plus control. The number and dry weights of weed plants, Percentage of Weed Inhibition (PWI), some vegetative growth, yield, and qualitative properties of grapes were measured. A Randomized Complete Block Design (RCBD) was used. All results were analyzed using Statistical Package for Social Sciences (IBM SPSS Statistics for Windows, Version 24.0). The differences between means were compared using Duncan’s multiple range test at a 5% level. Results revealed that herbicides significantly decreased the number, biomass, and PWI of broad and narrow-leaved weeds and total weeds in all growth stages. Furthermore, all treatments led to an increase in the number of clusters.vine-1, cluster weight, total yield, and WI, and the highest values appeared in the treatment with herbicides, followed by eucalyptus leaf extract and peels of pomegranate as compared to the control. Peels of pomegranate recorded the highest leaves’ chlorophyll content. For dry weight of leaves and qualitative parameters like TSS and TA%, all treatments led to minor effects that did not reach the degree of significance compared to the control at both locations. Thus, plant extracts can be used as a bioherbicide to control and manage some weeds.