Inga alley cropping
Encyclopedia
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
Environment Agency
The Environment Agency is a British non-departmental public body of the Department for Environment, Food and Rural Affairs and an Assembly Government Sponsored Body of the Welsh Assembly Government that serves England and Wales.-Purpose:...

's all-time list of scientists, campaigners, writers, economists and naturalists who, in its view, have done the most to save the planet.

Using the Inga tree for alley cropping has been proposed as an alternative to the ecological destruction of slash and burn cultivation. 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

Inga trees are native to many parts of Central
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

 and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. Inga grows well on the acid soils of the tropical rainforest
Tropical rainforest
A tropical rainforest is an ecosystem type that occurs roughly within the latitudes 28 degrees north or south of the equator . This ecosystem experiences high average temperatures and a significant amount of rainfall...

 and former rainforest. They are leguminous, "fixing" nitrogen into a form usable by plants. Mycorrhiza
Mycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....

, a beneficial fungus 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.

History

The technique was first developed and trialled by tropical ecologist Mike Hands in Costa Rica the late 80s and early 90s. Research funding
Research funding
Research funding is a term generally covering any funding for scientific research, in the areas of both "hard" science and technology and social science. The term often connotes funding obtained through a competitive process, in which potential research projects are evaluated and only the most...

 from the EEC
EEC
EEC is an abbreviation that usually refers to the European Economic Community, the forerunner to the European Union.It may also refer to;* The East Erie Commercial Railroad, a shortline in Pennsylvania...

 allowed him to experiment with species of Inga. Although alley cropping had been widely researched, it was thought that the tough pinnate
Pinnate
Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...

 leaves of the Inga tree would not decompose quickly enough.

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
Canopy
Canopy may refer to:*Aircraft canopy, transparent enclosure over aircraft cockpit*Baldachin, cloth or permanent architectural feature that hangs over altar or throne as symbol of authority...

, 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
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...

 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
Honduras
Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...

 and Cameroon
Cameroon
Cameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the...

.

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
Weeds
Weeds may refer to:* Weed, a type of common plant* Weeds , an American comedy drama series, starting 2005* Weeds , a 1987 film starring Nick Nolte* "Weeds" , an episode of the TV series Millennium...

.

The trees are then carefully pruned. The larger branches are used for firewood
Firewood
Firewood is any wood-like material that is gathered and used for fuel. Generally, firewood is not highly processed and is in some sort of recognizable log or branch form....

. The smaller branches and leaves are left on the ground in the alleys. These rot down into a good mulch
Mulch
In agriculture and gardening, is a protective cover placed over the soil to retain moisture, reduce erosion, provide nutrients, and suppress weed growth and seed germination. Mulching in gardens and landscaping mimics the leaf cover that is found on forest floors....

 (compost
Compost
Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At its most essential, the process of composting requires simply piling up waste outdoors and waiting for the materials to break down from anywhere...

). 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
Pruning
Pruning is a horticultural practice involving the selective removal of parts of a plant, such as branches, buds, or roots. Reasons to prune plants include deadwood removal, shaping , improving or maintaining health, reducing risk from falling branches, preparing nursery specimens for...

 the Inga also makes its root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

s die back, thus reducing competition with the crops.

External links

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