A survey to document peanut farmers' weed management practices was conducted in the Ashanti, Brong Ahafo, Eastern, and Volta regions of Ghana, West Africa during 2001. Peanut was planted as the only crop in 64% of fields surveyed. Land preparation method was related to land tenure system. The slash and burn system constituted 72% of farmers surveyed. In Brong Ahafo region, 80% of the farmers planted on ridges while peanut was planted flat primarily in the Volta region. Planting flat or on ridges was variable in Ashanti and Eastern regions. Cogongrass
Peanut is grown successfully in many tropical and subtropical countries worldwide because of its adaptability to a wide range of climatic and soil conditions and its nutritional value.
Management of weeds in sub-Saharan Africa constitutes an estimated 40% of the total available farm labor (Akobundu, 1987). Weeds not only affect yield through direct interference but also serve as alternate hosts for insects, nematodes, and diseases. Consequently, determining the relationships among weed management practices and prevalence of other pests is essential.
Inconsistent weed management practices for peanut production necessitated the need for a survey to determine farmers' practices influencing weed management in southern Ghana in order to develop a comprehensive strategy that improves weed control in the region. The objective of this article is to summarize results of the survey of weed management practices in southern Ghana.
A survey was conducted in the Ashanti, Brong Ahafo, Eastern, and Volta regions of Ghana during 2001. These regions included Forest, Forest-Savanna transition, and Coastal Savanna ecological zones with bimodal rainfall that allows for two cropping seasons within a year. The forest zone that comprises the Eastern and part of the Ashanti regions has annual rainfall of 1400 to 1750 mm while the transition covers the entire of Brong Ahafo and a portion of the Ashanti region with a rainfall of 1200 to 1400 mm. Both zones have similar temperatures ranging from 28 to 31 C. The Volta region, which is part of the Coastal Savanna zone, has annual rainfall of 600 to 900 mm with temperatures of 22 to 31 C. The study involved surveying farmers from nine villages in the Volta region, four from the Ashanti region, seven in the Brong Ahafo region, and four villages from the Eastern region.
Data were collected randomly through individually or groups of 2 to 3 interviews conducted in the field. Percentages of farmers employing land preparation in the categories of tillage by tractor, slash and burn; slash, burning, and manual ridging; slash, burn, and mounding, and tillage with hand implements and mounding were determined in relation to land tenure system. Land preparation systems were also compared among production regions. Farmers were also asked to list the most troublesome weeds in their peanut production system. The farmer also provided the perception of the ability to control weeds. The effectiveness of weed control pooled over land preparation system was listed qualitatively in the categories of poor, fair, or good. Farmers were also asked to list estimates of peanut yield loss under the different production systems.
While surveying farmers, five quadrants of 1.0 m2 were randomly placed in surveyed fields during mid season and number of weeds by species recorded. Common name, Latin binomial, and authority of weeds reported in this article are presented in
Fifty-six percent of fields were less than 0.4 ha with 44% between 0.4 and 0.8 ha (
When peanut was not grown in a monoculture system, peanut was almost always grown in association with corn (
The three land preparation systems included slash and burn, tillage with a tractor, and tillage using hand implements. Peanut was planted flat, in mounds, or on ridges. The slash-burn method of land preparation with any of the planting methods constituted 72% while tillage with a tractor or using hand implements were listed by 25% and 4% of respective respondents. Land preparation method was often associated with land tenure system (
Cogongrass was ranked as the most abundant weed across all regions by 41% of farmers (
Wild poinsettia was mentioned by 33% of farmers as the most deleterious weed (
Sixty-five percent of farmers reported fair weed control while 12% and 23% of farmers perceived weed control to be poor and good, respectively (
Ninety-one percent of those who reported poor weed control methods did not know how long their lands had been fallowed before farming (data not presented). Control of butterfly pea, cogongrass, Jamaican crabgrass, and wild poinsettia was considered poor by 50, 74, 100, and 67% of farmers, respectively (
The combination of land preparation method and planting seemed to influence peanut yield loss (r = 0.45, p = 0.05). Farmers perceived that peanut yield loss could be in the range of 21 to 80% if weeds are not controlled timely or appropriately (
Weed sampling revealed three major genera of nematodes were found associated with weed roots and included Meloidogyne, Pratilenchus, and Paratrichodorus (
Since agricultural practices can result in changes in occurrence of individual weed species, it is important to have information on the most frequent species in particular cropping systems and how their control affects costs and crop yields. Knowledge of the weed management practices employed by farmers is also vital in developing control measures for a country where most of the fields belong to small-scale farmers who rely mostly on manual weed control, a time consuming and labor intensive practice.
The authors are grateful to the staff of Plant Health Division of the CSIR-Crops Research Institute and USAID for the financial support through Peanut CRSP, USAID (Grant No. LAG-G-00-96-90013-00).
Crops Research Institute, P. O. Box 3785, Kumasi, Ghana.
Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
Departments of Entomology, Plant Pathology, and Crop Science, North Carolina State University, Box 7620, Raleigh, NC 27695.