Full Length Research Paper

Effects of some physical and chemical characteristics of soil on productivity and yield of cowpea (Vigna unguiculata L. Walp.) in coastal region (Cameroon)

Ndema Nsombo Eugène¹, Etame Jacques¹, Taffouo Victor Désiré^2* and Bilong Paul¹

¹Department of Earth Science, Faculty of Science, University of Douala, P.O. BOX 24157 Douala, Cameroon.

²Department of Botany, Faculty of Science, University of Douala, P.O. BOX 24157 Douala, Cameroon.

*Corresponding author. E-mail dtaffouo@yahoo.com.  Tel: (237) 75 90 03 50.

Accepted 4 January, 2010

Abstract

Studies were conducted to assess the response of cowpea (Vigna unguiculata L. Walp) to some physical and chemical characteristics of soil in coastal region (Cameroon). The cowpea variety used in this trial was Tsacre, planted at a spacing of 80 cm × 80 cm. The experimental design was a randomized complete block comprising of five plots with three replicates. Productivity parameters (dry weight aerial parts, roots dry weight, abortion seeds rate, number of flowering per plant, flowering rate) and yield components (number of seeds per pod, number of pod per plant, grain yield, pod yield and weight of 1000 seeds) were determined. Soil samples were taken randomly from depths of 0 - 30 and 30 - 60 cm before seeds sowing. The results showed that the plot with the highest percentage of sand (71.80%), the lowest percentage of clay (21.00%) and silt (7.20%) and with the highest amount of organic matter (10.26%), exchange potassium (0.36 g Kg^-1), calcium (0.49 g Kg^-1) and magnesium (0.46 g Kg^-1) increased significantly (P<0.05) the dry weight aerial parts from 4291 to 7051 mg, the roots dry weight from 293 to 454 mg, the number of flowering per plant from 8.10 to 28.82 and the flowering rate from 47.75 to 93.33%. Similar results were obtained with yield components where the number of pod per plant increased from 5.90 to 16.12, the grain yield from 729.70 to 2381 Kg ha^-1, the pod yield from 1251.21 to 1679.21 Kg ha^-1 and the weight of 1000 seeds from 81.70 to 145g. Results from this investigation showed that soil properties could influence cowpea growth, productivity and yield under Cameroon coastal growing conditions.

Key words: Cowpea, chemical composition, particle size distribution, productivity, yield.