Vegetation Management of Cover Plants Reinforcing Irrigation Facilities by Conventional Farm Practices in the Inland Valleys of Ghana

Abstract

In the light of an increasing population growth in Ghana, it is urgently necessary to improve the rice yield by controlling weeds, recognized as a factor constraining rice production in the inland valleys of Ghana. At the irrigation facilities with cover plants, it is important to establish a maintenance technology for the introduced plants to prevent weed growth and to develop weed suppression technique which do not adversely affect rice growth when cover plants invade the paddy fields. Moreover, it is necessary to study the effects of conventional farming practices on cover plant growth. From this viewpoint, three experiments were implemented with three test plants that could be introduced as cover plants. By applying three herbicides already in use, glyphosate, propanil and butachlor, which are generally applied to the whole paddy field with mature weeds right before rice transplanting in the study area, the growth of test plants was suppressed. The same effect was observed with a quarter of the applicable herbicide quantity recommended by extension workers. We have confirmed that these test plants began to regrow one week after burning and so making annual replanting of test plants unnecessary. Burning saves labor-intensive weeding of invading plants, replanting test plants and cutlass slashing. Test plants survived under two months of flooding and regrew in four months after drainage. It was demonstrated that these plants could be completely eradicated by combining a glyphosate application and flooding for more than two weeks.