Inga alley cropping

Inga alley cropping refers to the plantation of agricultural crops in between the rows of Inga trees. It has been promoted by Mike Hands, 44th in the UK Environment Agency's all-time list of scientists, campaigners, writers, economists and naturalists who, in its view, have done the most to save the planet. ^[1]

Using the Inga tree for alley cropping has been proposed as an alternative to the ecological destruction of slash and burn cultivation.^[2] The technique has been found to increase yields. It is sustainable as it allows the same plot to be cultivated over and over again thus eliminating the need for burning of the rainforests to get fertile plots.

Inga tree

Main article: Inga

Inga trees are native to many parts of Central and South America. Inga grows well on the acid soils of the tropical rainforest and former rainforest. They are leguminous, "fixing" nitrogen into a form usable by plants.^[3] Mycorrhiza, a beneficial fungus ^[4] growing within Inga roots was found to take up spare phosphorus, allowing it to be recycle into the soil.

Others benefits of Inga include the fact that it is fast growing with thick leaves which, when left on the ground after pruning, form a thick cover that protects both soil and roots from the sun and heavy rain. It branches out to form a thick canopy so as to cut off light from the weeds below and withstands careful pruning year after year.^[3]

History

The technique was first developed and trialled by tropical ecologist Mike Hands in Costa Rica the late 80s and early 90s. Research funding from the EEC allowed him to experiment with species of Inga. Although alley cropping had been widely researched, it was thought that the tough pinnate leaves of the Inga tree would not decompose quickly enough.^[2]

As the crops grow, so does the Inga. When the crops are harvested the Inga is allowed to grow back. Once more it closes the canopy, is pruned, and the cycle is repeated, time and again. When the tree is pruned the leaves fall on the ground and rot down and phosphorus is released for the crops. The fungi again take up spare phosphorus. Thus the cycle is repeated time and again.

Not only do the farmers grow their basic crops of maize and beans, but also they now grow cash crops with this system. Previously this was not possible because when the plot was a good distance from the farmer's home he would not have been able to guard it, or give the crops all the attention they might need. But with the same plot being used continuously it can be near his home, thus allowing his family to help to tend and guard it, even when there are young children.

The Inga would be used as hedges and pruned when large enough to provide a mulch in which bean and corn seeds could be planted. This resulted in both improving crop yields and the retention of soil fertility on the plot that was being farmed. Hands had previously seen the devastating consequences that could be caused by continuous slash and burn agriculture while working in Honduras, and this new technique seemed to offer the solution to the environmental and economic problems faced by so many slash and burn farmers.

While the technique that has the potential to save rainforest and lift many out of poverty, Inga alley cropping has so far failed to reach its full potential. The charity, Rainforest Saver considers Inga farming as one of the best agro-meteorological replacements for the slash and burn cultivation and is currently supporting Inga Projects in Honduras and Cameroon.

Method

For Inga alley cropping the trees are planted in rows (hedges) close together, with a gap, the alley, of say 4m between the rows. An initial application of rock phosphate has kept the system going for many years.

When the trees have grown, usually in about two years, the canopies close over the alley and cut off the light and so smother the weeds.

The trees are then carefully pruned. The larger branches are used for firewood. The smaller branches and leaves are left on the ground in the alleys. These rot down into a good mulch (compost). If any weeds haven't been killed off by lack of light the mulch smothers them.

The farmer then pokes holes into the mulch and plants his crops into the holes.

The crops grow, fed by the mulch. The crops feed on the lower layers while the latest prunings form a protective layer over the soil and roots, shielding them from both the hot sun and heavy rain. This makes it possible for the roots of both the crops and the trees to stay to a considerable extent in the top layer of soil and the mulch, thus benefiting from the food in the mulch, and escaping soil pests and toxic minerals lower down. Pruning the Inga also makes its roots die back, thus reducing competition with the crops.

References

1. ^ David Adam, Earthshakers: the top 100 green campaigners of all time The Guardian, 28 November 2006
2. ^ ^{a b} Elkan, Daniel. Slash-and-burn farming has become a major threat to the world's rainforest The Guardian 21 April 2004
3. ^ ^{a b} rainforestsaver.org: What is Inga alley cropping?
4. ^ Guinness, Bunny. A "miracle cure" The Sunday Telegraph 5 December 2004

with Inga in alley-cropping indicate that these systems are rather flexible, ... References.

Hands, M.R. 1988. The Ecology of Shifting Cultivation. Unpubl. ...

• T.D.Pennignton and E.C.M. Fernandes (editors) "The Genus Inga, Utilization" Inga species and alley-cropping by Mike Hands, Kew Publications.

External links

• sustainable farming with inga alley croppping in camaro
• alley-cropping
• Inga alley cropping as an agrometeorogical service to slash and burn cultivation
• What is inga alley cropping?