تغییرات گونه‌های علف های هرز مزارع برنج استان خوزستان در شرایط خشکه کاری

In the world and in Khuzestan Province, Direct Seeded Rice (DSR) is considered the most important method of rice cultivation. Weed density and diversity vary depending on the method of transplanting and direct-seeded rice. One of the major challenges in rice production is the presence of weeds. Samples were taken from the fields in the province of Khuzestan (cities of Shush, Dezful, Shushtar and Bavi) to identify and diversify of weeds in 2023. The most common species of grass weed, jungle rice (Echinochloa colona) (with a density range of 20-600 p/m2), has been recorded. After, jungle rice, the weed nutsedge (Cyperus spp) (5-160 p/m2) has the highest abundance. Weeds like bearded sprangletop (Leptochloa fusca), Vipergrass (Dinebra retroflexa), goosegrass (Eleusine indica), and crowfoot grass (Dactyloctenium aegyptium) have been listed as new-emerged weeds. Common Purslane (Portulaca oleracea), cutleaf groundcherry (Physalis angulate) and Jute mallow (Corchorus olitorius) introduced as broadleaves weed and sesbania (Sesbania rostrata) plant as new-emerged broadleaf weeds in some farms. Bispyribac-sodium is the most commonly used herbicide and shows weak control on grass weeds, especially for jungle rice. The most important problem of the rice fields in the province of Khuzestan is the presence of the weed known as the bearded sprangletop (Leptochloa fusca). All available herbicides to control it have been unsuccessful. Therefore, new herbicides will need to be registered in the coming years to achieve the desired grain and also to control weeds, especially the new-emerged weeds. On the other hand, considering the limitations of registered herbicides in directed seeded rice, the use of other cultural methods such as rotation, steal seedbed, sowing date, seed consumption, and varieties with higher competitive ability are recommended.