Groundnut (Arachis hypogaea L.) Response to Phosphorus and Weed Management in the Guinea Savannah Zone of Ghana

Abstract

Field studies were conducted during the 2013 and 2014 cropping seasons at the experimental field of the CSIR-Savanna Agricultural Research Institute, Nyankpala, to evaluate the response of groundnut to phosphorus fertilizer and manual weed control. A total of twelve treatments comprising four levels of phosphorus (0, 15, 30 and 45 kg.ha-1) and three weeding regimes (weedy check, weed free, and weeding at 3 and 6 WAP) were laid out in a randomized complete block design with three replications. Results indicated significant differences in canopy spread, effective nodulation, fresh and dry pod weights, weed biomass, 100 seed weight, haulm weight and soil arthropod pest densities and damage due to weeding regime and phosphorus interaction in both seasons. Weeding at 3 and 6 WAP plus 30 or 45 kg.ha1phosphorus reduced soil arthropod activity similar to weed free plots and improved all the yield parameters measured. Canopy spread, effective nodulation and pod yield correlated positively (r = 0.72 0.95) with haulm weights in both seasons. Although, similar growth and development were observed in the weed free and weeding at 3 and 6 WAP plots, for reasons of labour and cost envisaged in the practice of weed free farming, weeding at 3 and 6 WAP and application of 45 kg P.ha-1 is recommended for maximizing groundnut production in northern Ghana.

Keywords

• arthropods
• Ghana
• groundnut
• Guinea Savannah
• phosphorus and weeds