Assessment of Manual and Chemical Weed Control Methods on the Performance of Mungbean (Vigna radiata [L.]) in Awka, South East Nigeria.

Abstract

A field trial was conducted at Awka to evaluate the effect of manual and chemical weed control methods on Mungbean (Vigna radiata L.) growth and yield parameters. The study was laid out in a randomized complete block design, replicated five times. The four treatments were hoe weeding at 4 and 8 weeks after sowing (WAS), application of atrazine at the rate of 1.5kg a.i/ha at 4 and 8WAS, hoe weeding at 4WAS followed by application of atrazine at the rate of 1.5kg a.i/ha at 5WAS, and weedy check. The various treatments had no significant effect on mungbean growth measured parameters except on the number of branches where hoe weeding at 4WAS followed by application of atrazine at 5WAS had the highest number of branches at 6WAS (35.1). At 8WAS, application of atrazine at 4 and 8WAS had the least broad leaf weeds density (1.2) which showed that it is very effective against broad leaf weeds. The control (weedy check) significantly had the highest weed fresh weight (315g) and weed dry matter (88g) which showed that the various treatments were effective in the control of weeds in mungbean production. Application of atrazine at 4 and 8WAS had the highest number of pods per plant (15), mean weight of pods (10.27g) and weight of 100 seeds (4.93g). This showed that application of atrazine at the rate of 1.5kg a.i/ha at 4 and 8WAS effectively controlled the weeds and had no significant effect on yield of mungbean. The weed control efficiency and weed index showed that application of atrazine at 4 and 8WAS (64.3%, -3.0%) and hoe weeding at 4WAS followed by application of atrazine (51.4%, -18.0%) were more efficient in weed control. The result also indicated that application atrazine at 4 and 8WAS, hoe weeding at 4WAS followed by application of atrazine significantly produced higher seed yield and heavier seeds compared to weedy check. Application of atrazine at 4 and 8WAS is recommended for large scale mungbean production and areas where labour is scarce/very expensive since it was cheap and effective in mungbean weed control. While, hoe weeding at 4WAS followed by application of atrazine is therefore recommended for small scale production since it was effective in controlling weeds and also a type of integrated weed control method.