Effect of Cropping Practices on Weed Species Composition in a Groundnut (Arachis hypogaea, L.) Crop in Central Malawi

Abstract

The effect of rotation and weeding practices on weed species composition were evaluated in a groundnut (Arachis hypogaea, L.) crop in a three-year field experiment in Central Malawi under ridge-tillage practices. Weeding practices consisted of weeding twice including earthing-up, weeding once, and no weeding, respectively, for the duration of the groundnut crop. The number of individual weed species was determined and used to plot weed frequency graphs and derive weed diversity index.

It was shown that although the groundnut crop had more than a dozen week species, the most dominant species were Commelina benghalensis, Rhynchelytrum repens, Eleucine Indica, Bidens pilosa, Acanthospermum hispidus. Although the effect of the hoe-weeding regimes on the subsequent weed flore were subtle, it is evident that inter-row cultivation had the effect of reducing the prevalence of certain weed species early in the season while enhancing diversity and density above ground through recruitment from the seedbank. Sunflower, as the preceding crop in rotation, was an effective crop in reducing size of the subsequent weed flora in rotational cropping.

UNISWA Research Journal of Agriculture, Science and Technology Vol. 4 (1) 2000: pp 106-112