Title : Ethnobotanical survey and abundance of weeds in selected Manihot esculenta (cassava) Crantz farms in Osun state, Nigeria
Abstract:
This study identified and classified weed species found in selected cassava farms in Osun State. It also surveyed and documented the ethnobotanical importance of weeds found in the farms and determined the abundance of weeds in the study area. These were with the view to providing an inventory of weed species in selected cassava farms. Three study locations (A, B, and C) representing Ile-Ife, Ilesa, and Osogbo, respectively, in Osun State, were used for the study. In the three study locations, nine cassava farms were sampled. Weed species from each study location were evaluated using quadrat and line transect methods (systematic sampling). Each cassava farm was divided into three sections, irrespective of their sizes. At random, a 10 m narrow cutline was marked at every 2-meter point and placed on the farm with both ends tied to cassava stems. A 50 cm by 50 cm quadrat was placed at each marked point for sampling. The weed species were identified with the help of a taxonomist, and those whose identities were in doubt were identified using the West Africa Flora. Classification of weed species across all study locations was done based on their morphological characteristics, into broadleaves, grasses, and sedges. Through questionnaire administration and oral interview, the ethnobotanical significance of some of the weed species common to all study locations was documented with the assistance of farmers and local residents in the study area. The abundance of each weed species was determined through visual examination and counting the number of individuals of each species found on each farm. Means, frequencies, and percentages were used to analyze the abundance and ethnobotanical properties of the weed species. The results showed that a total of 74 weed species were identified within the study location. The Eighteen (18) of the weeds common to all cassava farms in the three study locations were documented, and their cultural and medicinal uses were reported. Weed species with the highest frequency of citation and percentage frequency index were Corchorus olitorius (97.14), Talinum triangulare (88.57) and Chromolaena odorata (75.71) while weed species with the least values were Pouzolzia guineensis (1.43), Platostoma africanum (2.89) and Cleom rutidosperma (4.29). Site A had the highest species composition, followed by Site B and Site C (51, 43, and 40) respectively. Family Asteraceae was the most abundant across the study sites, and this was attributed to their ubiquitous nature. The study concluded that weeds were a common and significant component of cassava farming systems in the selected study location. The ethnobotanical study further revealed that some weed species were beneficial to cassava farmers and residents.
