FARMER-PARTICIPATORY EVALUATION OF GREVILLEA ROBUSTA IN BOUNDARY PLANTINGS IN SEMI-ARID KENYA

Abstract

ABSTRACT Farmer-participatory tests were conducted near Machakos in semi-arid Kenya during 1994–1996 using grevillea (Grevillea robusta) to test the hypothesis that small-scale farmers could meet their needs of fuelwood and poles by boundary plantings of adapted trees. The average tree survival after one year varied from 37 to 84%, and the average height in the first two years ranged from 0.5 to 1 m per year, depending on the seasonal rainfall. The trees did not affect the performance of adjacent crops during the first 18 mo of planting. However, they later reduced crop yields, but only in the first two rows. Of the five tree species tested on the farms, eucalyptus (Eucalyptus camaldulensis) was the fastest growing tree, followed by melia (Melia volkensii), grevillea and senna (Senna spectabilis). Markhamia lutea was not adapted to the semi-arid environment, and the majority of trees of this species died. When farmers evaluated the trees they found grevillea and eucalyptus to be susceptible to termites, and senna and melia to be tolerant. However, they preferred grevillea for planting along internal field bunds and farm boundaries because of its fast growth, straight poles and little competition with crops. They preferred eucalyptus and senna for planting in small woodlots. Application of neem cake to seedlings at the beginning of the dry season was as effective as using ‘Furadan’ in preventing termite attack. Farmers planted trees eagerly when seedlings were supplied locally, either free and or on a cost price basis. Tree planting on small farms was constrained by lack of knowledge of adapted tree species for the region, poor availability of tree seedlings or seeds, difficulty of transporting seedlings from the source of supply to farms, theft, termites and drought. The indications are that farmers adopt tree planting if the constraints related to seedling availability near farms are removed. The study confirms that grevillea planting on farms contributes to the household wood requirements and provides additional income over time.