Evaluation of Legumes as Cover Crops for Soil and Weed Management in Smallholder Coffee Cropping Systems in Central Kenya. Research Concept Note. Issue No. 11: 19-21

Abstract

The performance of 14 legume species sown under coffee was studied during the long rains season 2005 in two experimental sites in Kiambu and Murang’a Districts in Central Kenya. Crotalaria Oclroleuca (G.Don) produced the highest biomass at 9 and 10 Weeks After Planting (WAP) on average of 1.5 t ha -1 . By 24 and 29 WAP Desmodium uninatum (Jacq,) DC, Desmodium intortum (Mill.) Urb, Mucuna pruriens (L) DC, Vicia benghalensis L. and Neontonia wightii (Arn.) had the highest biomass on average of 4t ha -1 . Crotalaria Ochloleuca (G.Don) had the highest percentage crop cover (73%) by 9WAP, late maturing and perennial legumes developed cover slowly but maintained the cover longer as compared to the early maturing legumes which developed cover rapidly and dried up in about 100 days after planting. By 24 and 29 WAP Desmodium uncinatum (Jacq,) DC, Mucuna pruriens (L.) DC (mottled) and Desmodium intortum (Mill.) Urb had a percentage crop cover of over 80%. Intercropping with late and maturing LCC reduced weed counts by 369 m -2 at 7 WAP to 52m -2 3

at 52 WAP. Late maturing legumes like Mucuna pruriens (L.) DC, Desmodium uninatum (Jacq,) DC, Desmodium intortum (Mill.) Urb maintained high ground cover longest and suppressed weeds better than all the other legumes. Desmodium uncinatum (Jacq,), Crotalaria Ochroleuca (G.Don) and Neoutonia wightii (Arn.) extracted the highest soil moisture at all levels tested (0-100 cm) with Mucuna pruriens (L) showing no significant difference from the sole coffee. Mucuna pruriens (L) DC (mottled) recorded the highest litter fall (433 kg ha -1 ) at 24 WAP while Neontonia wightii (Arn) recorded the lowest (115 kg ha -1 ) in same period.