ABSTRACT

Abstract

Weed infestations usually consist of several species present at various densities and frequencies and emerge at different times to compete with the crop for essential farm resources. The experiments were conducted in 2016 and 2017 raining seasons at Bayero University Kano in the Sudan savanna agro-ecological zone of Nigeria to evaluate the effect of weed phytosociological characters on their control methods in upland rice. The experiment consisted of twenty weed control strategies by the use of Butachlor at two levels i.e 1.0 and 1.5 kg a.i. ha^-1 (pre-emergence), Orizo-plus (2,4-D+Propanil) at two levels i.e. 2.8 and 4.5 kg a.i. ha ^-1, Rainbow-SD (Penoxsulam) at two levels i.e 0.025 and 0.030 kg a.i. ha^-1 and Solito 320 EC (Pretilachlor +Pyribenzoxim) also at two levels i.e 0.320 and 0.480 kg a.i. ha^-1 (post-emergence). All the post-emergence herbicides were applied in various combinations with Butachlor and in some cases followed by supplementary hoe weeding (SHW) at 4, 8 and 4 & 8 weeks after sowing (WAS). Weed free and weedy plots were employed to serve as control. The experiments were laid out in a randomized complete block design and replicated four times. The result indicated that use of Butachlor at 1.5 kg a.i. ha^-1fb Orizo plus at 4.5 kg a.i. ha^-1 to produce significantly lower weed cover score and dry weight, as well as higher weed control efficiency and paddy yield. It also revealed that in area with high relative density and frequency of grassy weed like Rottboelia cochinchinensis, Digitaria horizontalis, Cynodon dactylon, and sedges such as Cyprus rotundus, Fimbriyalis ferruginea, Kyalingya squamulata to resist normal doses of herbicides unless followed by supplementary hoe weeding at later stages of the crop growth.