The role of plant residues in soil productivity: farmers' knowledge and practices in Embu District, Kenya

Abstract

Plantresidues from trees, crops or weeds playan important role in determining the soil fertilitystatus in smallholder farmers of the centralhighlands of Kenya region. A study wasconducted in Embu district of Kenya, locatedin the densely populated windward side of the south-eastern slopes of Mount Kenya,to document farmers knowledge and practices in the prevalence and utilisation ofthese residues. A total of 134 small-scale farmers cutting across five major agroecological zones of the 30 km transect were interviewed. Farmers indicated that trees, crops or weed residues found in their farms were associated with generation of plant residueswhicheitherimproveorimpoverish the farm niches where they are found. Plant residues that were associated with soil fertility enhancement included: Zea mays, Physeolus vulgaris, Grevillea robusta, Combretum molle, Cordia africana, , sycomorous, and Camellina sinensis. other hand, the residues of Eucalyptus saligna, Macadamia integrifolia, Cupressus lusitanica, Croton megalocarpus, mearnsii, Sorghum bicolour and Mangifera indica continued to impoverish the soil in the farm fields where they occur. The farmers years attributed the good or poor crop performance in farm sections with certain types of plant residues to the decomposability as well as the levels of crop nutrients contained in these residues. The implication of these farmers' perception on the farming patterns prevailing in this region were that there was a shift toward more cultivation of crop or trees species that were associated with soil fertility enhancement.