Agroforestry

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Photograph taken from Google (credit goes to Google )

Agroforestry  is land use management system in which trees and shrubs are grown with the  crops or pastureland. It combines shrubs and trees in agricultural and forestry technologies to create more diverse, productive, profitable, healthy,
ecologically beneficial, and sustainable land-use systems.
Agroforestry is a collective name for land-use systems involving trees combined with crops and/or animals on the same unit of land. It combines:-                                                   
* Production of multiple outputs with protection of the resource base.
* Places emphasis on the use of multiple indigenous trees and shrubs.
* Particularly suitable for low-input conditions and fragile environments.
* It involves the interplay of socio-cultural values more than in most other land-use systems and,
* It is structurally and functionally more complex than monoculture.

Agroforestry is any sustainable land-use system that maintains or increases total yields by combining food crops with tree crops and  livestock on the same unit of land, either alternately or at the same time, using management practices that suit the social and cultural characteristics of the local people and the economic and eco­logical conditions of the area.

Social forestry

Social forestry is defined as “Forestry outside the conventional forests which primarily aim at providing continuous flow of goods and services for the benefit of people. This definition implies that the production of forest goods for the needs of the local people is  termed as Social forestry. Thus, social forestry aims at growing forests of the choice of the local population.
Shah (1985) stated that Conceptually Social forestry deals with poor people to produce goods such as fuel, fodder etc. to meet the needs of the local community particularly underprivileged section.

Alley cropping

Alley cropping corn fields between rows of walnut trees.
With alley cropping, crop strips alternate with rows of closely spaced tree or hedge species. Normally, the trees are pruned before planting the crop. The cut leafy material is spread over the crop area to provide nutrients for the crop. In addition to nutrients, the hedges serve as windbreaks and eliminate soil erosion.

Alley cropping has been shown to be advantageous in Africa, particularly in relation to improving maize yields in the sub-Saharan region. Use here relies upon the nitrogen fixing tree species Sesbania sesban, euphorbia tricalii, Tephrosia vogelii, Gliricidia sepium and Faidherbia albida. In one example, a ten-year experiment in Malawi showed that, by using the fertilizer tree Gliricidia (Gliricidia sepium) on land on which no mineral fertilizer was applied, maize yields averaged 3.3 tonnes per hectare as compared to one tonne per hectare in plots without fertilizer trees nor mineral fertilizers.

Boundary systems

A riparian buffer bordering a river in Iowa.
There are a number of applications that fall under the heading of a boundary system. These include the living fences, the riparian buffer, and windbreaks.

A living fence can be a thick hedge or fencing wire strung on living trees. In addition to restricting the movement of people and animals, living fences offer habitat to insect-eating birds and, in the case of a boundary hedge, slow soil erosion.Riparian buffers are strips of permanent vegetation located along or near active watercourses or in ditches where water runoff concentrates. The purpose is to keep nutrients and soil from contaminating surface water.Windbreaks reduce the velocity of the winds over and around crops. This increases yields through reduced drying of the crop and/or by preventing the crop from toppling in strong wind gusts.

Taungya

Taungya is a system originating in Burma. In the initial stages of an orchard or tree plantation, the trees are small and widely spaced. The free space between the newly planted trees can accommodate a seasonal crop. Instead of costly weeding, the underutilized area provides an additional output and income. More complex taungyas use the between-tree space for a series of crops. The crops become more shade resistant as the tree canopies grow and the amount of sunlight reaching the ground declines. If a plantation is thinned in the latter stages, this opens further the between-tree cropping opportunities
Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned and allowed to revert to their natural vegetation while the cultivator moves on to another plot. The period of cultivation is usually terminated when the soil shows signs of exhaustion or, more commonly, when the field is overrun by weeds. The length of time that a field is cultivated is usually shorter than the period over which the land is allowed to regenerate by lying fallow.

Shifting Cultivation

Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned and allowed to revert to their natural vegetation while the cultivator moves on to another plot. The period of cultivation is usually terminated when the soil shows signs of exhaustion or, more commonly, when the field is overrun by weeds. The length of time that a field is cultivated is usually shorter than the period over which the land is allowed to regenerate by lying fallow.

Why we need Agroforestry !!

The increasing population will need a lot of household wood products, paper
products, packing material and fire wood. To meet the growing demand we can't rely
on the forests alone, so private agroforestry is inevitable. India's per capita
consumption of paper and paperboard is less than 10kg and whereas China is 72kg.
The productivity of timber in India is only 0.7 cubic meters /ha/year whereas the
world average is 2.1 cubic meters /ha/year. India's forests are covered in 69 million
hectares i.e. 19.5% of the country's area, the availability of forest land per person in
India is one of the lowest in the world at 0.08 ha, against an average of 0.5 ha for
developing countries and 0.64 ha for the world. The demand for timber was 85
million cubic meters in 2008 and now it is expected to cross 153 million cubic meters
by 2020, the supply of wood from forests are projected to 60 million cubic meters
by 2020. This means India needs to depend on imports or else agroforestry in private
and community lands for its growing wood requirements.
Increased cost of cultivation, non availability of farm labor, higher farm wages and
various reasons farmers are switching to less investment and less labor intensive
farming like short term commercial crops and forestry plantations. Agroforestry
system is mostly practiced by the large farmers who have alternative source of
income rather than agriculture, It won't viable to small farmers since they need
annual returns on agriculture for their livelihood. But some of the areas the small
farmers also cultivating the agro forestry by inter cropping the food crops    
between the rows up to one or two years or till the trees get bigger, which is a good
sign for food security and wood security.
Leucaena and Eucalyptus trees are widely cultivated in Andhra Pradesh which give
the guaranteed farm income and the yield of each acre is used to be between 25- 30
tonnes for every four years as the trees are harvested only afer 4 years.The wood
pulp is being used in paper industry and as well as plywood, particle boards and
wood veneer. The waste wood has been used in bio mass power generation plants as
a substitute to coal and other fossil fuels to reduce the green house gas emission. In
Prakasam district alone has more than one lakh acres have been cultivated and
producing 10 lakh tonnes of wood valued around Rs 390 crores annually. The market
price has increased recently up to Rs.3900 per tonn due to the shortage of wood
and fair competition among the firms in industry which is a lucrative income for
farmers. Most of the progressive farmers would like to adopt agroforestry model for
sustainable agriculture to improve the farm productivity and profitability.
Indian has achieved self sufficiency in food production, now we should focus on
ecology, preserving our fossil fuels and also cater the growing wood demand caused
by population growth and economic development. The agroforestry system is
capable to sequestrate the massive amounts of carbon that helps to mitigate the
danger of green house gas concentrates. We can implement this system in large
barren lands, farm boundaries to improve soil fertility and water conservation. There
is a remarkable scope in agroforestry to focus on the ecological issues, biomass
production, catle fodder and various outputs to industries as well as employment
generation.
Tree crop interaction
Under the agroforestry system the interaction between
tree and crop are studied in positive, negative and neutral
way. This interaction are depends upon the type of model
including varying species, their nature and composition.
Further, interaction is defined as the effect of one
component of a system on the performance of another
component and/or the overall system (Nair, 1993). Agroforestry and soil health
The property of soil under agroforestry practices is
depend on tree species and their intercropping pattern,
management practices, arrangement direction and the
quantity and quality of litter and their decay rate. Trees are
simultaneously planted in rows sparsely in crop field
and/or along the alies (bunds). These trees provide food,
timber, fuel, fodder, construction materials, raw materials
for forest-based small-scale enterprises and other cottage
industries and in some cases, enrich soil with essential
nutrients (Ghosh et al., 2011).

Agroforestry and microclimate amelioration
Trees on farm bring about favourable changes in the microclimatic
conditions by influencing radiation flux, air temperature, wind speed,
saturation deficit of understory crops all of which will have a
significant impact on modifying the rate and duration of
photosynthesis and subsequent plant growth, transpiration, and soil
water use (Monteith et al., 1991).
Scope and Potential
The scope and potential of agroforestry is envitable. Tree species are
adopted in a large hectare of boundaries, bunds, wastelands area and
permits in the field where most annual crops are growing well.
Agroforestry for CO2 mitigation
Climate change is a burning issue of the world. Rise in CO2 level
accelerate the global warming which necessitated the sink and
sequestration of carbon.
Socioeconomic development
Agro-forestry as a land use system that integrates trees, crops and
animals in a way that is scientifically sound, ecologically desirable,
practically feasible and socially acceptable to the farmers (Nair,
1979).