Global Advanced Research Journal of Agricultural Science (GARJAS) ISSN: 2315-5094

September 2013 Vol. 2(9): pp. 231-241

Copyright © 2015 Global Advanced Research Journals

Full Length Research Paper

Efficacy and economics of manual and chemical weed control strategies in the first year of conservation agriculture adoption in the highveld areas of Zimbabwe.

Rugare Joyful Tatenda and Mabasa Stanford

University of Zimbabwe, Crop Science Department, P.O Box MP 167, Harare, Zimbabwe.

*Corresponding Author’s Email: rugarejoy@yahoo.co.uk; 

 Tel: +263 777 334 777

Accepted 02 September, 2013

Abstract

Adoption of conservation agriculture in Zimbabwe can be increased by the development of effective and economical weed control strategies. On station trials were carried out at two sites with contrasting soil textures namely,  Domboshava Training Centre and Thornpark Estate in the 2007/8 rainy season to evaluate the effect of manual weeding, atrazine, glyphosate and a combination of the two herbicides on weed biomass, labour requirements for weed control, maize biomass, grain yield and economics of weed control. The experiment was laid out as Randomised Complete Block Design with three blocks and five treatments at each site. Weed counts were done whenever weeds were ten centimetres tall or ten centimetres length in weeds with a stoloniferous growth habit. Weed control strategy had no significant effect (P > 0.05) on weed biomass at Domboshava Training Centre and Thornpark Estate at first and second weeding, but had a significant effect (P <0.05) at the third weeding at both sites. The Zamwipe (hand held weed wipe) strategy had significantly lower (P < 0.05) labour requirements than the other weed control strategies, but its use resulted in low plant populations and concomitantly low yields and economic returns at Domboshava Training Centre. The traditional manual hand hoe weeding strategy had the highest labour requirements at both sites. However, weed control strategy did not cause significant (P > 0.05) grain yield differences at both sites. The use of a tank mix of glyphosate and Atrazine resulted in the highest net benefit returns at Domboshava Training Centre and Thornpark Estate. Under the present circumstances, it can be concluded that the glyphosate + atrazine at planting + manual weeding strategy is the most economic weed control strategy in conservation agriculture.

Keywords: Conservation Agriculture, Weed Control Strategy, Economics, Herbicides, Manual weeding.