Alley Cropping

Alley Cropping is a technique of planting trees in lines between alleys of crops. There are many different ways of alley cropping, depending on factors of soil nutrients, water availability, and the purpose of using trees. In the Sahel region of Cameroon, this is usually a rotational system, used in conjunction with corn or peanut cultivation. It is a rotational system because there is often not sufficiant rain to have continual cropping every year between the growing trees. It works a little like this:

Year 1: plant trees in rows of 4-8 meters; cultivate as usual between trees
Year 2: depending on height of trees and the shade the produce, as well as amount of water available to the trees and crops, you may be able to plant your crop again between the trees.
Year 3: let the trees continue growing

Year 4/5: coppice trees (cutting the tree near the ground, leaving a stump which will sprout again). Leave the leaves and small branches on the ground and take the wood for your own use. Start a 3 year cycle of letting the trees grow and coppicing. Every third year, you cut the trees and cultivate the land.

Because it is a three year cycle, it is a good system to use for three fields, cutting and cultivating in one field while letting the trees grow in the other two, rotating the cultivation each year. In addition, because this system takes a bit of time to accrue the benefits, and because the farmer will be sacrificing two periods of cultivation, it is a good system to use on fields that would remain in fallow, or those which already have very low fertility.

Benefits: Year after year, the trees shed their leaves which fall into the field adding organic matter. Building up organic matter in fields is one of the main desires in the Sahel, as fields become more and more infertile. With little coverage in the dry season, winds steal topsoil and when rain comes, it washes nutrients away. Much of the soil is very sandy and in some places seeming straight sand. In addition to increased soil fertility and thus crop harvest, the trees have the added benefit of wood, useful for firewood or construction.

While there are a few people who have done this in fields in neighboring villages, using Cassia Siamea in the culture of peanuts, I have not seen it in Mafa Kilda, and will be doing a demonstration field of this technique. I will be doing half a quart of peanuts, and half a quart of soy, using two species of trees (Cassia Siamea and Leucaena leucocephela) to see if there is a difference in results. Both trees have good biomass, producing many leaves and branches quickly. Leucaena, in addition, is leguminous, meaning its roots fix nitrogen in the soil making it more available to other plants. I asked for a field that could rest with the Peace Corps volunteer for 8 years, is close to the center of the village, but also a field that is very infertile. While I will not see the results of the work, the soil fertility taking several years to build, hopefully, the volunteers following me will continue the work and demonstration of the system, and by the fifth year, the soil fertility should have risen enough to produce visible results. I'm also hoping to plant a "haie vive" (live fence) of Acacia senegal, Acacia polyacantha, Acacia nilotica and Moringa oliefera. The acacias are spiny trees which will (hopefully) keep the goats and cows from entering the field. Moringa, a good nutritional tree, is small, however grows easily and quickly and hopefully will create a bit of a boundary in the meantime, while waiting for the acacia's to grow. I hope to attach some photos of the trees and field throughout the process.