👨🏻‍🌾 Agro-Forestry

• Agroforestry has developed as an interface between agriculture and forestry in response to the special needs and conditions of tropical developing countries.

• Agroforestry is a collective name for land-use systems involving trees combined with crops and/or animals on the same unit of land.
• Bene et al. (1977) defined agroforestry as a sustainable management system for land that increases overall production, combines agriculture crops, forest plants and tree crop and/or animals simultaneously or sequentially and applies management practices that are compatible with the cultural patterns of a local population.
• Even the simplest AFS is more complex ecologically (structurally and functionally) and economically, than a monocropping system.

Difference between Social Forestry and Agroforestry

Attributes of Agroforestry

👉🏻 There are three attributes which, theoretically, all agroforestry system possesses, these are:

• Productivity: Most, if not all, agroforestry systems aim to maintain or increase production (of preferred commodities as well as productivity (of the land). Agroforestry can improve productivity in many different ways. These include: increased output of tree products, improved yields of associated crops, reduction of cropping system inputs, and increased labour efficiency.
• Sustainability: By conserving the production potential of the resource base, mainly through the beneficial effects of woody perennials on soils, agroforestry can achieve and indefinitely maintain conservation and fertility goals
• Adoptability: The improved or new agroforestry technologies that are introduced into new areas should also conform to local farming practices.

Benefits of agroforestry

Environmental benefits

• Reduction of pressure on forest.
• More efficient recycling of nutrients by deep-rooted trees on the site
• Better protection of ecological systems.
• Reduction of surface run-off, nutrient leaching, and soil erosion through impeding effect of tree roots and stems on these processes.
• Improvement of microclimate, such as lowering of soil surface temperature and reduction of evaporation of soil moisture through a combination of mulching and shading.
• Increment in soil nutrients through addition and decomposition of litter-fall.
• Improvement of soil structure through the constant addition of organic matter from decomposed litter.

Economic benefits

• Increment in an output of food, fuel wood, fodder, fertilizer and timber;
• Reduction in incidence of total crop failure, which is common to single-cropping or monoculture systems
• Increase in levels of farm income due to improved and sustained productivity.
• Agroforestry is considered as an alternative land use system for wasteland development.

Social benefits

• Improvement in rural living standards from sustained employment and higher income
• Improvement in nutrition and health due to increased quality and diversity of food outputs
• Stabilization and improvement of communities through elimination of the need to shift sites of farm activities.

Scope of Agro-forestry In India

• There is tremendous scope for Agroforestry because India has achieved self-sufficiency in food production.
• Now its attention is becoming more focused on the ecological problems and shortage of fuel, fodder and other outputs as well as unemployment.
• Agroforestry has vast scope in meeting this requirement through multipurpose tree species as:
  • large area is available in the form of farm boundaries, bunds, waste lands where this system can be adopted.
  • This system permits the growing suitable tree species in the field where most annual crops are growing well.
  • By growing trees and crops on Agricultural or forest land, Resources are utilized efficiently
  • System has potential generate employment.
  • Provides raw material for the cottage industries
  • Helps in maintaining ecological balance
  • Soil and water conservation, soil improvement.
  • Helps in meeting various needs of growing population.

Constraints in agroforestry

1. Interference effects

• In an agroforestry system, trees being the dominant partners, will compete with the herbaceous substratum for resource pools of light, water and nutrients.
• When the immediate supply of a single necessary factor falls below the combined demands of the plant, then the competition begins.
• The interference of trees decreases the crop yield which is lower than the monocropping.
• The tree canopy absorbs maximum light and causes competition for light.
• Felling of trees causes damage to the arable crop.
• The competition is also referred as Allelospoly.

2. Environmental aspects

• Possible competition of trees with food crops for space, sunlight, moisture, and nutrients which may reduce food crop yields.
• Damage to food crops during tree harvest operations.
• Potential of trees to serve as hosts to insect pests that are harmful to food crops.
• Damage due to birds.

3. Socioeconomic aspects

• Requirement for more labour inputs, which may cause scarcity at times in other farm activities.
• Competition between food and tree crops, which could cause aggregate yields to be lower than those of a single crop.
• groforestry system requires more for its management
• Longer gestation period for tree delay the returns to the farmer.
• Farmers give more weight-age to field crops compared to tree crop.
• Resistance by farmers to displace food crops with trees especially where land is scarce.

4. Allelopathy

• Muller (1969) emphasized that allelopathy, the direct or indirect effect of one plant upon another through the production of chemical inhibitors (allelochemicals) that are released in to the environment.
• Most of the chemical substances involved in allelopathic reactions are secondary compounds.
• The toxic metabolites mainly found in leaves, but are also distributed in other plant parts.
• Summer materials are more toxic than those of rainy and winter season.
• Toxins released from plant litter are the primary causes of allelopathy.

Minimising Constraints in agroforestry

👉🏻 Silvicultural options for minimizing the negative interactions:

1. Manipulation of Densities and Arrangement of Trees
   • The negative effects of trees can be minimized by increasing the spacing between the trees.
2. Manipulation of Tree crown and roots
   • The negative effects of trees can be further reduced by pruning of tree crown and roots.
   • In alley cropping system, pruning of trees and applying the biomass to the soil will reduce the trees’ competitive ability and increase the growth yield of the associated intercrops by providing green manure and by allowing more light to the intercrops.
   • In situations of severe root competition for moisture and nutrients, root pruning operation or trenching may eliminate or reduce the negative effect trees on the intercrops.
3. Choice of Agricultural crops
   • There is a great need to identify the suitable agricultural crops which can grow well under trees with limited solar energy available.
   • Example:
     

     

4. Choice of trees
   • Through skillful management practices any or all of these constraints can be controlled. For example, once it is known that trees compete with food crops and may reduce food yields, it is easy to adopt some or all of the following strategies:
     • Select legume trees that have small or light crowns so that sufficient sunlight will reach the food crops for photosynthesis. Trees belonging to Mimosoideae and Fabaceae family can fix atmospheric nitrogen.
     • Select tree species that are deep-rooted so that they will absorb moisture and nutrients from the deeper subsoil while the food crops receive their share from the surface layer of the soil.
     • Space the trees farther apart to reduce their competitive effects on the food crops. Certainly, agroforestry has considerable potential, not as the only way to improve agricultural production, but as one important way to enhance and maintain overall productivity of the small upland farm, the agricultural unit that is becoming more prevalent in many parts of the world.

Choice of Species for Agro and Farm Forestry

👉🏻 Following considerations mainly motivate the selection of species in social forestry:

• Ability to regenerate
• Capacity to grow under wide range of environment, soil types, rainfall etc.
• Easy decomposition of litter or leaves
• Easy in establishment and ability to coppice
• Fast growth and easy establishment
• Fixation of Nitrogen, Ex: Leucaena leucocephala, Khejari.
• For recreation and shade plants with quick growing and give shade and pleasing colour like Spathodia, Gulmohar, Cassia, Jakaranda are selected.
• High yield of wood and fodder
• Multiple use of wood like Subabul
• No competition with field crop.
• Plant with deep tap root system
• Plant yielding small timber
• Rapid growth

Management Practices

Thinning

• Felling made in immature stand for the purpose of improving the growth and form of the trees that remain without permanently breaking the canopy.
• It is mainly done:
  • To improve the hygiene of the crop by removing dead, dying and diseased trees
  • To ensure best physical conditions of growth
  • To obtain a desired type of crop
  • To afford protection from the spread of insects and diseases
  • To improve the quality of wood
  • Increase the net yield and financial return from the crop

Pruning

• Removal of live or dead branches or multiple leaders from standing trees for the improvement of the tree or its timber.
• It allows the grower to manipulate the growth and development of the trees left after thinning to improve the quality of the tree and to increase agriculture returns.
• Natural: natural death and fall of branches of standing trees grown closely due to deficiency of light or decay etc.
• Artificial: Removal of branches with sharp tools in a dense crop.
• Pruning lower branches close to the trunk of tree makes small knotty core which gives clear straight grain timber.
• Removal of too many branches will retard the growth
• If pruning is done too late, the central core of knotty wood become large thus reducing value of tree.

Pollarding

• Pollarding consists of cutting a sapling or pole tree at some height above the ground level so that it produces new shoots from below the cut.
• Pollarding is done at a height of 2 - 2.5 m above ground level; e.g. in Salix spp., Hardwickia binata, Grewia optiva, Morus alba, etc.

Lopping

• Removal of one-year shoots or fresh growth from entire crown of the tree/plant in order to get sufficient fodder for livestock is known as lopping.
• Lopping is extensively done in Moruis alba, Grewia, Bauhinia, etc.

Coppicing

• Cutting or heading back of main stem at 20 - 30 cm from the ground level.
  • Strong coppicers: Acacia catechu, Albizia lebbek, Anogeissus latifolia, etc.
  • Good coppicers: Aesculus indica, Chloroxylon swietinia, Hardwickia binata, etc.
  • Bad coppicers: Adina cordifolia, Bambax ceiba, etc.
  • Non coppicers: All conifers.

Bending

• Restricting the development of bole to allow more food material to new leaf shoots.
• Bending and coppicing are useful when it is desirable to produce large quantity of foliage close to ground level.

Training

• In agroforestry vertical spread of the tree is a desirable feature, therefore trees raised in agroforestry systems must be vertically trained to avoid shade and light competition to underground crop.

Research Institutes

ICRAF

• The systematic research in agroforestry geared up after establishment of International Council for Research in Agroforestry (ICRAF) in 1977 and the ancient practice of AF was instutionalized for the first time.
• Its headquarters is in Nairobi, Kenya.
• Renamed as The International Centre for Research in Agroforestry (ICRAF) in 1991.
• Now known as World Agroforestry Centre (WAC).

NRCAF

• National Research Centre for Agroforestry.
• Its head quarter is in Jhansi, UP, India.
• To undertake basic and applied research for developing and delivering technologies based on sustainable agroforestry practices on farms, marginal and wastelands for different agroclimatic zones in India.
• To co-ordinate network research with the SAUs/ ICAR Institutes/ other related research institutes for identifying technologies which can be transferred from one region to another.
• To provide training in (a) research methodologies and (b) use and application of technologies developed at various levels.
• To develop technological packages of different agroforestry practices for various agro-climatological zones for transfer to farm field and wastelands.
• To act as repository of information on the subject.
• To collaborate with relevant national and international agencies for achieving the mandate.
• To provide consultancy.

IGFRI

• Indian Grassland and Fodder Research Institute
• Its head quarter is in Jhansi, UP, India
• To conduct basic, strategic, applied and adaptive research; development and training in forage production and it’s utilization.
• Is the premier R&D institution in South Asia for sustainable agriculture through quality forage production for improved animal productivity.