Cogongrass is widespread in the moist savanna and forest zones of West Africa, where recurrent fires, tillage, weeding, and other farm activities continuously disturb land. Field experiments were conducted in the forest–savanna transition zone of Nigeria from 1996 to 2000 to evaluate the potential of two cover crops (velvetbean and tropical kudzu) for reclaiming land that had been abandoned to cogongrass. Cover crops were grown on the same plots for 3 consecutive yr (1996 to 1998). The control was natural fallow dominated by cogongrass in 1996 to 1998. Corn was planted in all treatments in 1999 and 2000. Total dry matter of cogongrass before the treatments were imposed was 9,000 kg ha−1, and rhizomes contributed 49% of this. At all subsequent sampling dates, plots with cover crops had lower cogongrass shoot and rhizome dry matter than plots without cover crops. Shoot dry matter was reduced to zero 65 wk after planting in both cover crops; rhizome dry matter was reduced to zero after 97 wk in velvetbean plots and after 105 wk in tropical kudzu plots. Corn grain yield was 60% higher in plots with tropical kudzu and 102% higher in plots with velvetbean than in control plots without any previous cover crops. Further research is required to integrate use of cover crops with other control methods for improved cogongrass management.
Nomenclature: Cogongrass, Imperata cylindrica (L.) Beauv. IMPCY; corn, Zea mays L. ‘Oba Super II’; velvetbean, Mucuna cochinchinensis (Lour.) A. Chev. MUCCO; tropical kudzu, Pueraria phaseoloides (Roxb.) Benth. PUEPH.