Improved Crotalaria cover crop fallow system for sustainable maize production in the northern Guinea Savanna agroecological zone of Ghana

Abstract

An on-station trial was carried out at the Research Farm of the Faculty of Agriculture, University for Development Studies, Tamale, in the northern Guinea Savanna agroecological zone of Ghana. The study compared different seeding rates of leguminous cover crops, inorganic fertilization, and a combination of the two in a small-scale cereal-based production system. The experiment was conducted for 2 years within a 3-year fallow system to investigate the use of Crotalaria ochroleuca and Crotalaria retusa as 1 and 2 years' fallow systems. Crotalaria ochroleuca seed fallow at 50 kg ha^-1 was more efficient in above-ground biomass production and nutrient accumulation than Crotalaria retusa seed fallow at 50 and 100 kg ha-1 of cover crop regrowth. The above-ground biomass production and nutrient accumulation by the Crotalaria species at 100 kg ha^-1 of seeds was higher than at 50 kg ha^-1 of seeds. The results showed that C. ochroleuca and C. retusa can accumulate higher soil nutrients at higher seed rates. The average grain yield increase for all the treatments between 2001 and 2002 were 4.6 and 3.0 per cent for "Dobidi" and "Okomasa" at 100 kg ha^-1 of Crotalaria seeds, respectively. Grain yields from the Crotalaria fallow species plus fertilizer performed better, followed by fertilizer treatment and Crotalaria fallow systems. Two years' Crotalaria fallow systems at 100 kg ha^-1 were more profitable than at 50 kg ha^-1.