Agro-forestry is a collective name for land use system where woody perennial (trees, shrubs and palms) are deliberately planted on the same land management units as agricultural crops and or animals in some form of spatial arrangement or temporal sequence. In other words, agro-forestry is simply a form of land management system in which forest management, food production and conservation form integrated components. Agro-forestry is normally viewed in the context of food production, forest production and environmental conservation.
IMPORTANCE OF AGRO-FORESTRY
The type of land and the combination of plants and animal that constituted an agroforestry system has the following importance to man and his environment.
- Production of food crops: The combination of the growth of food crops within some forestry trees do help in the production of food for farmers.
- Production of trees: Economic trees which are of importance to man are deliberately planted to provide timber and other forest products like fuel, wood,
- Rearing of animals: Certain agroforestry practices do help in the rearing of livestock animals by the deliberate planting of pasture plants.
- Production of pasture: Also the practice of certain agro-forestry do assist in the development of pasture where livestock animals can graze.
- Maintenance of soil fertility: The practice of agro-forestry do assist in the maintenance of soil fertility through the growth of some nitrogen fixing plants.
- Provision of wind breaks: The practice of some agro-forestry ensure that planting of certain trees that can serve as wind break in a particular area.
- Soil and water conservation: Trees in agro-forestry systems do promote soil and water conservation through cover cropping and growth of leguminous crops.
- Provision of living fences: Some trees are deliberately planted along farm boundaries to serve as living fences as a kind of protection.
ROLES OF TREES IN AGROFORESTRY
Trees generally play important roles in agro-forestry practice. Some of the roles of trees in agro-forestry include:
- Alley cropping: This is a system of agro-forestry which involves the growing of food crops in spaces between hedge-rows of trees or shrubs, which must undergo regular pruning every five or six weeks.
- Homegardens and other multistory system: Home gardens, mixed planting of annual and tree crops around dwellings are common types of multistory agroforestry system. Multistory means that there are at least two layers of plants growing to different heights in the system. In home gardens, the lowest level often consists of vegetables or root crops, the second level includes fast growing trees or crops such as banana, spices and cocoa, a third higher level consist of large trees that provide fruits, timber and shades. Home gardens also provide a pleasant shaded living area.
- Living fences: In many places, farmers plant multipurpose trees in rows along farm boundaries as “living fences” in addition to providing folder and fuelwood, living fences provide privacy and protection from browsing animals.
- Wind breaks: Trees also provide windbreaks. Wind breaks are stripes of trees, shrubs, and vines planted closely together along the edges of croplands perpendicular to prevailing winds. Especially in dry areas, windbreaks can provide protection to crops and soils from the detrimental effects of wind.
- Improved fallow system: Trees play important role in agro-forestry through the bush fallow system. In this system, blocks of fast-growing trees, particularly species that fix nitrogen in the soil, can help that soil recover as well as provide fuel, poles and fodder. Farmers can plant stump cuttings in the fields at the same time as the harvest of the last annual crops before the fallow period. The cuttings do not shade other crops until after 4-6 months.
- Trees and raising livestock: Farm systems that combine tree plantations with livestock that graze beneath them are found generally in drier areas, where natural grasslands and farm sizes are larger. In such systems, farmers graze sheep or cattle on forage grasses or in stands of trees.
Advantages of integrating tree growing with livestock production
- Increase in production of meat: The combination of tree growing and livestock production help to increase the production of meat protein without sacrificing large tracts of agricultural land.
- Reduction of soil erosion: The system helps in reducing soil erosion by preventing open grazing and reducing dependence on grasses.
- Addition of organic manure: The use of animal manure to fertilise the soils and intercrops, helps in reducing reliance on in organic fertilizer.
- Provision of income: The system also help to provide additional income to farmers through sale of livestock.
- Stabilisation of stream banks and gullies: Trees can help to reduce soil erosion along streams and gullies. They should be planted at the medium to high level water mark. Their roots serves to hold the soil in place and reduce the impact of storm water.
TYPES OF AGRO-FORESTRY PRACTICES
Agro-forestry combines agriculture and forestry technologies to create more integrated, diverse, productive, profitable, healthy and sustainable land use system. The different agro-forestry combination are:
- Taungya system: Taungya system involves the planting of both food crops and forest trees on the same piece of land. In other words, it is a system which involves the integration of agriculture with forestry. Some of the conditions necessary for the practice of Taungya System include scarcity of land, over-population, unemployment, deliberate government policies.
- Forestry production on farm plots: Forestry production on farm plots is feasible only if there is demand for the forest products grown on the farm plots, otherwise there will be little incentive to the farmers to plant trees. However, if the gains in soil fertility are clearly demonstrated, farmers may be willing to introduce and maintain trees. The tree species used in these efforts must be fast-growing to produce marketable products in a short time.
- Food production within the forest ecosystem: This involves the deliberate production of crops in a typical forest environment. However, the type of crops to be cultivated must be able to adapt to the forest environment. The forest canopy must be open up by killing and clearing the tree underneath so that sufficient light is available for the growth of the crops. This system is aimed at food production by increasing the intensity of clearance and by the use of shade tolerant food crops that do not endanger the tree species.
- Production of livestock: Animals can also be reared in a forest environment. This involves the planting of quality grasses and legumes with the forest belts which provide food for the grazing farm animals especially ruminants.
- Production of pasture: Animal grasses e.g. elephant grasses and some leguminous plants can be planted deliberately within a forest zones. The purpose of this is to produce nutritional feed for livestock such as cattle, sheep and goat.
TREE SPECIES, SUITABLE FOR AGRO-FORESTRY PRACTICES
Agro-forestry involves raising trees in combination with other agricultural enterprises including livestock. Different species of trees can be planted with many types of crops in a variety of ways. For examples, fast-growing trees can be planted when the land is fallow or they can be grown at the same time as agricultural crops. In addition to providing fodder, fuel, wood and other products trees in agroforestry system promote soil and water conservation, enhance soil fertility and act as wind breaks for nearby crops.
What are the best multipurpose trees for agro-forestry?
It is important to select the most suitable trees since it is not easy to replace them once they have been planted. The following factors should be considered when selecting tree species.
- Environmental adaptation: A multipurpose tree must be able to adapt to the climate, soil, topography, plant and animal life of the area.
- Need of the farmers: The species should meet the needs of the farm families. For this reason, it is important to involve farmers both men and women in selecting species to plant.
- Ease of maintenance: Farmers should consider the ease of maintenance of selected species so that little time and skill will be needed to take care of the plant species.
- Availability of genetic materials: Seeds or seedling of the species being considered must be easy to obtain. If vegetative propagation is required, farmers should receive training on how to do this.
Some examples of tree species suitable for agro-forestry
Some tree species are purposely used for agro-forestry such trees can also be use for other purposes as follows;