Plant Propagation: A Teaching Resource Packet with Emphasis on Agroforestry and Fruit Trees in East Africa

Abstract

The products and services provided by trees have always been used in farming. In the past, trees grew naturally on farm lands. The rise in population, and resulting increased demand for wood products, has led to loss of tree cover through cutting down of trees without replacement. Land shortage is common in most parts of Uganda, and therefore land for establishing separate wood plantations is not available. Agroforestry becomes the most obvious and appropriate alternative. Agroforestry is a term used for land-use systems in which trees or shrubs are grown together with crops or combined with livestock. Trees can be combined with other components, either simultaneously being grown in a field with crops, or in rotation where trees are grown first then cut and replaced with crops. Agroforestry is a technology through which the problems of poor agricultural production, wood shortages and environmental degradation can be addressed. Trees provide many products such as fuelwood, poles, shade, fodder, fruits, medicine and timber. Trees planted as contour hedges for soil and water conservation help reduce water and soil loss and improve infiltration rate. Trees also maintain soil fertility through nutrient recycling, nitrogen fixation and improving soil structure. Trees are also used as windbreaks, for providing shade and beautifying the landscape. Trees suitable for agroforestry should have characteristics that are highly beneficial to farmers. This usually depends on the technology or tree arrangement desired by the farmer and the final products needed. For instance, a fast-growing aggressive tree species may be very useful for rotational systems but may compete too much with crops. Table 9. Desirable characteristics of agroforestry trees for selected practices Tree characteristics Improved Boundary Scattered in Contour fallow planting crop fields planting Nitrogen fixing – – Fast growing – – – Coppicing – – – Deep rooted – – – Light canopy – – Suitable for fodder – – Compatibility with crops – – – Quick recovery – – – Lots of biomass – – 6.3 Propagation of trees There are three methods of propagating trees: ● Seed ● Vegetative propagation ● Collecting wild seedlings (wildings). Most trees are raised from seed. Successful raising of seedlings and growing of trees depends on timely availability of good-quality seed.