Tuesday 4 December 2012

Agroforestry- Integration and Diversification



This video gives a quick overview of
  1. What silvopasture is (a form of special form of agroforestry which includes livestock on the land)
  1. Experiences/ Benefits of farmers
  1. Considerations to take into account


Constantly repeated phrases/ concepts in this video include:
"Full Economic Potential"… "Compatibility"… "Management"… "Local"…. "Understanding"… "Single Integrated Practice" … "Diverse products"… "Reduced Economic Risk" … "Production and Conservation Benefits"...

Hmmm, "Production and Conservation Benefits"…!That seems to fit well into the principles laid out last week about having to attain both of these aims. Unlike mindless back to basics/anti-technology approaches, the above key words show us that it exploits the creativity and know-how of humans with less intensive resource consumption (cf green revolution which was very resource intensive).

What is agroforestry?

It is a "method of food production combining tree and shrub plantations and the farming of low-lying herbaceous plants. Agro-forestry is often recommended to enhance the biodiversity of agricultural ecosystems and improve production while reducing land degradation" (UNESCO glossary)

We have seen how agriculture has resulted in unfavourable landuse change in the form of deforestation. Although this approach does not entail complete conservation of forests, it allows reforestation by allowing forests to be integrated into current agricultural land and with added benefits.

Nair et al review agroforestry as a strategy for carbon sequestration: 

ARGUMENTS FOR:
Here are some of the Environmental/Food production benefits summarized from the review:
  • Integrating pastureland with trees allows higher biological efficiency resulting in greater direct (conversion into metal carbonates) and indirect (Soil Organic Carbon) sequestration in the soil, vegetation and biomass products (it is estimated that 30-50% of above ground production constitutes carbon!).
  • Greater diversity results in tighter cycling of nutrients and more stability and resilience
  • Decreased bare fallow allowing for more efficient use of precipitation and more productive use of the land by lengthening the growing season
How can these benefits be achieved?
  • Clean Development Mechanism whereby developed countries buy C credits (C sequestered at a lower cost than if carried out in their home country) to offset their emissions
  • Substituting energy intensive construction materials with wood
  • Planting favourable species such as those with higher lignocellulose contents, trees with greater growth potential before nutrient limitation sets in, mixed plantings to provide greater resistance and decreased competition for nutrients (Conant, 2011).

How feasible is Agroforestry as a solution?
In terms of  the scientific/ecological plausibility  (carbon sequestration potential, CSP) and food production objectives, it does have much potential, especially as a intermittent measure to remove elevated CO2 before more drastic societal/lifestyle changes can occur. It also a very efficient way of reducing emissions because transport is not necessary and small communities from remote areas who are in dire need of income can be helped immediately. That being said, there are still many social, economic and political barriers to be crossed as synthesized by Conant (2011), which I will summarize below:

ARGUMENTS AGAINST
  1. Lack of attention given to forestry projects under CDM hence there are relatively few real life examples now
  2. Lack of proper accounting procedures for Landuse Change and Forestry (LUCF) carbon sinks due to the difficulty in dismantling drivers causing changes in carbon stock leading to difficulty in quantification and valuation
  3. Undervaluation of carbon leading to no or lower comparative advantage as compared to conventional methods
  4. Lack of a low-cost method for ground-level documentation of  sequestration resulting in high costs which then conflicts with poverty alleviation
  5. Lack of a simple, flexible procedure that reduces entry barriers for small farmers

All these result in a lack of developmental benefits which ultimately lead to farmers' unwillingness to participate in such schemes- which Nair et al (2009) feel is the ultimate barrier. Perhaps it is most crucial that these barriers be crossed in the tropics where not only do tree species growing there have greater CSP but deforestation in the tropics is so high that it exceeds all transport emissions. And we can take heart that organizations and governments are implemented small measures showing great success :)

Clinton Global Initiative


Save the Children & the Thai government


(This is a clear case-study where environmental/biodiversity objectives being achieved together with food security and human development, as compared to conventional systems :))

On a side note, the issues faced by agroforestry in the developing world aren't too different from that faced by REDD (Reducing Emissions from Deforestation and Forest Degradation). If you would like to know more, check out Jessica's blog (especially this post on the desirability of REDD to indigenous peoples where she emphasizes that it is important for the local people to secure resource rights so that they can in reality receive the benefits they were meant to enjoy).  

2 comments:

  1. Hi Joy,

    This is quite a novel solution to deforestation, and it sounds very promising. In the video on the tree-planting initiative, how exactly does planting trees contribute to crop productivity? Also, what if certain ecosystems cannot sustain both these planted trees and agriculture, e.g. if they are semi-arid areas, etc. ? I'm guessing that agroforestry is only suitable for certain areas?

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  2. Hi Li Wen,

    I realised I didn’t really touch on yields besides the other environmental benefits in agroforestry, so thanks for pointing that out!

    Agroforestry increases crop productivity generally through these ways (You can refer to this for more: http://www.agroforestry.co.uk/afbens.html)
    1) Trees allow greater "natural fertilization" by access to more resources by extending deeper into the soil as compared to a monoculture. These resources are then fed to crops by litter fall.
    2) Tighter nutrient cycling occurs because of lowered runoff, erosion
    3) Better soil structure through porosity created by roots which allows oxygen and water infiltration
    4) Better microclimate under suitable shading
    5) Acting as fodder (food) for livestock i.e. fodder trees!
    6) (in the particular context of semi-arid regions especially,) trees also give the benefit of breaking the wind so protecting the crops and preventing soil erosion

    There is indeed conflicting success in the semi-arid regions. Vandenbeldt (http://www.fao.org/docrep/u5200e/u5200e09.htm)reviews this and concludes that it is viable in these regions but special care has to be taken in terms of the choice of species planted i.e. trees that do not require high amounts of water. In general for all agroforestry systems, it is important to understand the resource use of the trees as if wrong ones are chosen or overcrowding occurs from insufficient spacing, there could be negative interactions in the form of competition with crops instead. He also notes that it is not a panacea to the problems of monoculture but rather a tool to tackle some of the problems that would occur otherwise.

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