Evaluation of the Potential of Mucuna, Pueraria and Cowpea as Cover Crops in Tree Crop Plantations

Abstract

Nodulation, dry matter yield, nitrogen accumulation and the potential for weed control of cowpea (Vigna unguiculata), mucuna (Mucuna pruriens var utilis ) and pueraria(Pueraria phaseoloides ) cover crops were assessed in pot and field experiments at the University of Ghana, Legon and the Oil Palm Research Institute, Kade respectively. The response of these cover crops to bradyrhizobial inoculation in two soil series, Kokofu and Nzima, was also studied. Rhizobial inoculation on the average, increased dry matter yield of cowpea and mucuna. Pueraria phaseoloides, however, produced higher dry matter yield without inoculation than with inoculation. Mucuna pruriens var utilis Accession 1745 gave the highest shoot dry weight and shoot nitrogen content, with Pueraria phaseoloides recording the least shoot dry weight over the period of study in both experiments. Shoot dry weight did not differ significantly between the two soils, but generally the two mucuna accessions and cowpea produced higher shoot dry weights on Kokofu soil than Nzima. Pueraria phaseoloides produced the highest nodule number and nodule dry weight in both pot and field studies but this did not result in higher dry matter and nitrogen production. The two mucuna accessions effectively controlled weeds present including Chromolaena odorata, which was prevalent in the area. The relatively fast growth exhibited by mucuna indicates a potential for use as a cover crop for weed control in tree crop plantations especially during the early establishment phase.