Silvopasture : A Sustainable Way of Growing Trees, Forage and Livestock
In many developing countries, livestock production is a major contributor to gross domestic product. And agroforestry practices that are mainly concerned with the management of trees, forage and livestock is known as Silvopasture.
In silvopasture systems, forage crops are deliberately introduced into a timber production system, or trees are deliberately introduced into a forage production system. The interactions among timber, forage, and livestock are thus managed intensively to simultaneously produce timber, a high quality forage resource and efficient livestock production. Overall, silvopasture can provide economic returns while creating a sustainable system with many environmental benefits. These systems range from traditional silvopastoralism to very high intensity cut and carry fodder systems.
TRADITIONAL GRAZING SYSTEMS
Peace Corps volunteers throughout Central America’s degraded uplands have seen the damaging effect that livestock can have on the land. However, livestock are an essential component of farming through out the Developing World, as they provide labor, fertilizer, transport, and food. Animals are also a major investment for families and have many social implications. Therefore, we should take a closer look at how animals can fit into programs that save and restore degraded lands.
One of the most important points to remember and understand is that: animals are not causing the problems, management systems are. Most communities throughout the developing world allow their animals to roam the countryside, often herded by young men or boys. These herds of animals have a significant impact on the environment. They eat everything, including tree seedlings, and their hooves compact the soil, keeping forests from regenerating while causing long term damage to the soil. To make things worse, herding animals in the hot sun is an inefficient way to raise animals. They are stressed by the high temperatures and lack of water, just as people are, and the grasses and seedlings they graze on tend to be low in nutrients. It is now time to consider a new management system.
Before establishing silvipastoral systems in an area, one must assess the value of integrating forestry and agriculture for economic success and environmental sustainability compared to local land use. Environmental requirements (e.g., planting trees, stream-side protection and wildlife habitat maintenance) also may vary between locations. Select and use trees and planting/harvesting patterns that are suitable for the site, compatible with planned silvopastoral practices and provide desired economic and environmental returns,
DESIGN AND ESTABLISHMENT
Silvopasture can be established on any land capable of simultaneously supporting tree and forage growth. The pattern of the distribution of trees on the land is an important factor for silvopasture success. Trees can be evenly distributed over the area to optimize growing space and light for both trees and forage. Alternatively, grouping trees into rows or clusters concentrates their shade and root effects while providing open spaces for pasture production. Trees are typically pruned to increase light penetration and develop high-quality timber.
The management of silvopasture requires a good understanding of forage growth characteristics as well as the timing and duration of grazing to avoid browsing of young tree seedlings. Livestock should be excluded from tree planting areas during the first year of plantation establishment. Improper management of silvopasture can reduce desirable plants due to overgrazing and soil compaction.
The major silvopastue management tools include:
•Tree harvesting, thinning and pruning.
•Fertilization to improve both forage and tree production.
•Planting legumes for nitrogen fixation and forage production.
•Multi-pasture, rotational grazing.
•Developing water sources (e.g., stock tanks, windmills, ridge reservoirs, etc.).
•Using fencing, tubing, plastic mesh, repellents, and seasonal livestock exclusion to reduce damage to young seedlings.
One effective and highly profitable livestock management technique is to confine the animals, which is known as confinement rearing. In this system, the food is brought to the animals, the animals do not go to the food. This is also known as a cut-and-carry or zero-grazing system. In these systems, one acre of forage can maintain up to 20 cow-calf units.
In a cut-and-carry system, animals are penned m a specific area. Families use walls, thorny branches, poles, or living fences to keep the cows, sheep, or goats enclosed. This protects them from other people, pests, and diseases, and it keeps them from wandering.
Because animals are not allowed to graze in open lands, forage must be brought to them. This gives the owner an opportunity to select the very best food for the animals.
SELECTING FORAGE AND FORAGE TREES
There is a wide range of great animal forages that communities utilize around the world. Just like people, animals need a well-balanced diet. The ultimate goal of rearing animals is to provide them with living conditions that will help them stay healthy and reproduce quickly. Grass alone is not enough. Animals need protein, macro and micronutrients, minerals, and plenty of clean water.
The question is: What species of trees are useful for forage production? Almost every country in the tropical world has some species where the leaves are used as forage. Trees For The Future’s experience has largely been with the species of Leucaena leucocephala (ipil-ipil) because it grows well under a wide range of conditions, quickly coppices (grows back) when cut and produces a large quantity of leaves, even through the long dry season. The leaves are especially palatable and contain about 27.5% crude protein, plus high levels of vitamins A and D. Communities have also had success using grasses and bushes, including dwarf Napier/elephant grass, tephrosia vetch, and tree lucerne.
Over the past 32 years, Trees For The Future has helped livestock growers plant millions of trees. In the Philippines, Trees for the Future assisted 90 families to plant 66,000 trees, using the leaves to fatten cattle. A few years later, working with the Cattlemen’s Association of Madura, Indonesia, technicians helped them plant over 22 million trees. This increased the available forage supply by 15% – much of it in the dry season when the forage supply had always been dangerously low.
Nutritionists have pointed out that Leucaena is in the Mimosa family and the leaves contain an irregular (alkaline) amino acid called “mimosine”, which can reduce calving rates under certain circumstances. These leaves should be fed to single-stomach animals in limited amounts (25% for goats and sheep; none to horses or mules) but can be fed to large ruminants up to 30% of the total ration.
While Trees For The Future has assisted many forage projects to achieve good results, there is a great need for more research to determine even better methods to increase both the quantity and quality of animal protein for people and to bring income-generating trees back to the world’s degraded lands.
THE ECONOMICS OF CUT-AND-CARRY SYSTEMS
From an economic perspective, this is the obvious best choice. In upland areas, it usually takes anywhere from three to seven acres of land, depending on the type of forage, to maintain one cow-calf unit. With the confinement or cut-andcarry system, one acre of forage can maintain up to 20 cow-calf units.
Grazing systems are especially difficult to maintain in tropical areas where there are distinct rainy and dry seasons. Working with Banteng (an Asian relative to cattle), researchers learned that yearling bulls gain about 75 kg of body weight in the rainy season so, for the year, they should be able to gain 150 kg. However, in the dry season, they lose about 25 kg so they actually only achieve about 33% of their genetic potential.
Putting in a confinement system costs far less than installing and maintaining perimeter and division fences, especially on rough land where many livestock programs are located. Some raisers ask what can be done with all that rough land. One suggestion is to plant trees, including fruit and timber trees in combination with forage trees, to provide high quality forage for the herd, especially in the dry season.
Experience with these systems, much of it in Southeast Asia where the price of land makes it prohibitive to graze livestock, has shown that confinement rearing greatly improves production by generating more milk, faster gains, and a higher calving percentage because the animals are in the cool shade with clean water and better forage. There are no hills to climb, no insects, no snakes, no predators, and no hot sun. There is also far less sickness and mortality. The reason is simple: the animals are where you can keep an eye on them.
Because the animals are confined, daily management is far easier. Sickness and other problems can be quickly identified and remedied before it is too late. Because the cattle are comfortably housed with forage, clean water and minerals at all times, they waste far less energy compared to animals that spend their lives walking around the hot sun, always thirsty, and always plagued by insects and heat. Therefore more energy goes into the production of more calves, more milk to make them grow, and more meat to sell each year. Because the manure is easily captured, it serves as an excellent source of organic fertilizer that can be transported to crop fields, gardens, or nurseries.
Once again, this system depends heavily on the use of forage trees, which are the deep-rooted leguminous trees needed to restore the land. Thus, a high percentage of the ration, about 25% for most cattle, is available from the reforestation program. These tree leaves (especially ipil-ipil) have the ability to greatly increase growth rates and milk production, because they have high levels of protein. An average herd of dual-purpose cattle needs a ration of about 11 to 12% protein. Local grasses have about 6% in the rainy season and 4% in the dry season. Leaves of the ipil-ipil tree have about 27.5% protein, high levels of vitamins A and D, and are palatable to the animals.
Our program at the Trees For The Future has proven many times that improving the feed ration and decreasing the stress and energy requirements can double annual growth and milk production in an average herd.
Looking at this system from a national perspective, it is possible to rapidly increase livestock numbers through higher birth rates, without major investment. The average yield of meat or milk per animal can be increased as much as 40% because energy requirements are lowered and more of the forage goes into production. It also provides meaningful jobs in rural communities where they are needed most.
SOCIAL, ECONOMIC AND ENVIRONMENTAL BENEFITS OF SILVOPASTURE
Integrating trees, forage and livestock into a land use system raises the production of marketable products while maintaining long-term productivity. The system produces multiple products and hence reduces economic risk. Because the management cost for the timber and livestock component is spread out, the system provides relatively constant income from livestock/ product sale and sale of trees, fruit and timber products.
Grazing can enhance tree growth by controlling grass competition for moisture, nutrients and sunlight. Well managed grazing provides economical control of weeds and brush without herbicides, maintains fire breaks, and reduces habitat for persistent rodents. In addition, livestock manure recycles nutrients to trees and forage.
Trees that provide shade or wind protection can have a climate-stabilizing effect, reducing heat stress and wind chill of livestock. Trees can cut the direct cold effect by 50% and reduce wind velocity by as much as 70%. Planting trees on grazing lands is a protective measure that can improve livestock performance, reduce their mortality, and decrease their feed requirements. Moreover, silvopasture has the potential to improve water quality and wildlife diversity. The trees protect the soil from water and wind erosion, while supplying organic matter to improve soil properties. Unlike concentrated livestock management, silvopastoral systems are more environmentally friendly and less likely to raise environmental concerns related to water quality, odors, dust, noise, disease problems and animal treatment.
By Trees for the Future
Founded By Dave Deppner