Agroforestry – The potential for Social, Economic and Environmental benefits.
Introduction
Agroforestry is a land use system that allows for the concurrent production of trees and agricultural crops from the same piece of land. It has a rich history of development and has been practised in some parts of the world for more than 6,000 years. Much recent research into agroforestry has been carried out in the tropics and within the context of developing nations, where land shortages brought about by the rapid growth in population demand that efficient production systems for both wood and food be developed and enhanced.
Agroforestry began to attain prominence in the late 1970s, when the international scientific community realized its potentials in the tropics and recognized it as a practice in search of science. During the 1990s, the relevance of agroforestry for solving problems related to deterioration of family farms, increased soil erosion, surface and ground water pollution, and decreased biodiversity was recognized in the industrialized nations too. Thus, agroforestry is now receiving increasing attention as a sustainable land-management option the world over because of its ecological, economic, and social attributes.
The benefits of a sustainable tree cover for land rehabilitation, soil improvement, and the provision of firewood, fodder, timber and many other secondary products have been widely recognised. The need to increase tree cover is particularly acute in the context of rapidly expanding human populations and intensification of production. The use of multipurpose trees for agroforestry has the potential to respond to some of these needs.
Agroforestry systems provide great potential for job creation, local food and timber, non-timber products, carbon sequestration, biodiversity enhancement, soil, air and water protection, landscape improvement and eco-tourism. Such systems could provide Irish farmers with a wide range of opportunities that could add wealth to current farm business planning. Methods and practices of integrating forestry and agricultural production have been trialed over many centuries. Changes in agricultural systems are being driven by a need to create sustainable income and decrease environmental impact. Agroforestry systems are sinks for carbon and other nutrients.
The benefits
- Local production of resources providing local jobs
- Efficient nutrient capture due to greater root biomass in the subsoil
- Shelter and reduction of wind speed through crop canopies
- Diversification of products from arable systems
- Development of more complex ecosystems that can improve biological control of pests
- Biomass and biofuel production
- Carbon sequestration
- Education / Training resource
- Resilience to extremes of weather
Integrating trees and shrubs with the other enterprises on a farm can create additional sources of income, spread farm labor throughout the year, and increase the productivity of the other enterprises, while protecting soil, water, and wildlife. Agroforestry systems include alleycropping, silvopasture, windbreaks, riparian buffer strips, and forest farming for non-timber forest products. While they clearly offer economic and ecological advantages, these systems also involve complex interactions. Landowners should research the marketing possibilities and include the agroforestry system in the complete business plan for the farm.
Dr Martin Crawford, Directorof the Agroforestry Research Trust states : -
“Scientific research in the field of agroforestry has established beyond a doubt that polycultures, where several crops are grown together in the same space at the same time, can also produce greater yield (outputs) than similar areas of monoculture.
It is also scientifically proven that agroforestry and forest garden systems can improve soil fertility, soil structure, drainage etc. It is also well known from research in the organic agriculture field that soils can be improved very substantially via use of organic matter, nitrogen-fixing and mineral accumulating plants. Past history of the use of a site does not therefore condemn it to similar uses in the future. By use of the techniques mentioned above, in addition to providing wind shelter and other bioremediation techniques (such as the use of mycorrhizal fungi), soils and sites can be dramatically improved in quality and allow for complex agroforestry systems to
be established even on poor soils
I would add that in my view the biggest challenge that we all face in the next few decades is that of climate change. In terms of sustainability, annual plant-based systems are the least able to cope with climate extremes – droughts, floods, heavy downpours etc. which is how the most damaging effects of climate change will be manifested. Perennial and tree-based systems are
much more resilient to such extremes, and much more sustainable in the long term.”.
Trials and experiments
There are a number of key trials in the UK including those sited just outside of Leeds under the control of the Leeds University Agroforestry Research Group. These trials have demonstrated that alley farming of poplar trees with combinable crops can be integrated with arable cropping systems particularly on marginal land.
Agricultural experiments have recorded over 150 years of cropping, soil, water and atmospheric data. The Wilderness Experiments at Rothamsted in Hertfordshire catalogue the development of un-managed agricultural land into mature stands of trees. The datasets demonstrate how trees interact with the water and air environments to change the physical and chemical properties of soil. The Broadbalk Wilderness is a mature stand of mainly pedunculate oak, though the tree composition of the wilderness is diverse and the soil has become less acidic. There are plots that have been grazed with sheep showing the effect of different management approaches. The Wilderness also has plots that have tree saplings removed manually and are not grazed. These plots have a very diverse flora.
The wilderness experiments demonstrate the potential in managing landscapes differently. The importance of integrating farming and forestry systems has clear ecosystem benefits including carbon conservation and enhanced biodiversity.
Land management practices that are being used to increase income from agricultural and natural-resource activities in central Florida include: growing high value floral and herbal crops under trees; integrating livestock, timber production, hunting and ecotourism; alley cropping with vegetables; and more intensive management of riparian zones.
