Weed Control Efficiency of Management Practices of Lowland Paddy Production in Sudan Savanna Ecology

Abstract

Two concurrent experiments were conducted during the wet season of 2012 and 2013 at research farms of the Irrigation Research Stations of Institute for Agricultural Research (I.A.R), Ahmadu Bello University, Talata Mafara (12^o 34’ N; 06^o 04’E) and Kadawa (11^o39`N; 08^o02’E ) in the Sudan Savanna ecological zone of Nigeria to assess the efficiency of rice production practices in controlling weeds in rice. The treatment consisted of four (4) weed management practice (Oxadiazon at 1.0 kg a.i ha^-1 [pre-emergence], orizo-plus [propanil 360 g/l + 2,4-D 200 g/l] at 2.8 kg a.i ha^-1 [post emergence at 3 WAS], manual weeding [at 3 and 6 WAS] and weedy check [control]); three (3) each of seeding method (Drilling, Dibbling and Broadcast) and seed rate (40 kg ha^-1; 70 kg ha^-1; 100 kg ha^-1). The experiment was laid in a split plot design replicated three times. Weed management practice was assigned to the main plots while the combination of seeding method and seed rate to the subplots. The result indicated that weedy check was consistent in recording the highest weed growth in terms of weed dry weight and weed cover score. Manual weeding at 3 and 6 WAS was significantly more efficient in controlling the weeds followed by oxadiazon at 1.0 kg a.i ha^-1 then orizoplus at 2.8 kg a.i ha^-1. Broadcast method of seeding recorded significantly lower values for weed control efficiency and weed growth when compared with drilling and dibbling seeding methods at both locations and years of study. A higher than 40 kg ha^-1seed  rate increased weed suppression by decreasing weed dry weight indicating better weed suppression.

Keywords: Weed control efficiency, weed dry weight, lowland paddy