Wednesday, February 13, 2013

Terre Verte Guié- Holistic Systems Overview

Greetings from the Land of Men of Integrity (pays des Hommes integres.) I'm here at a pilot farm called Terre Verte (green earth) in a beautiful village called Guié in Burkina Faso, West Africa. This place is pretty amazing. Over the past thirty years, the Sahel has seen systematically worsening conditions of drought and dryness. The the folks at Terre Verte cite bush fires, overgrazing, cutting too much wood, and “mining agriculture” as factors that encourage the encroaching desert and make the landscape increasingly vulnerable... which leads to drought, loss of biodiversity to extinction, and famine.

Trench to plant a  haie vive, living fence
Here at Terre Verte, the main focus is on ways to conserve water and sediment in the landscape, preventing the erosion that accelerates the processes of desertification. This is done largely through the installation of mad windbreak hedgerows, or Wégoubri in the local tongue here called Mooré, or Le Perimetre Bocage in French. Almost every building, pathway, and garden plot here is lined with a row of Cassia sieberiana. I was shocked by the volume of C. sieberiana starts in the nursery, it's really a large focus of Terre Verte's approach. The concept haie vivre- living hedge- comes from Europe and was brought by Henri Girard, who started the farm here, but it goes along with the practices that were in place here before the period of "mining agriculture" began.

So now you're picturing large fields, each surrounded by a living hedge. They also have large berms around the perimeter to protect against and control brush fires, which can be wildly destructive. At the lowest point in every field, theres a small pond to retain water and  berms built up around it a little wider with the extra earth.  During the rainy season, the hole fills up with water and floods up to the berms, forming a stock that's used for watering until it's all gone. 
Diagrams credited to AZN

Okay, so now picture a row of trees running down the midline of the field. This provides shade for families working in the fields, where children can play or rest while parents work, and also helps prevent erosion. These trees are also productive: including Karite (which we know as shea, a la shea butter) fig, mango, guava, Moringa (an excellent tree which I'll probably post about) and tons of others. 

So, that should leave two large open sunny area's in the picture in your mind's eye. These are the main productive areas and are cultivated using a method called Zai holes. About a foot in diameter and half a foot in depth, Zai holes concentrate fertility and aeration for planting. This is a traditional method here in Burkina and the word Zai is Mooré but the technique has been widely adapted throughout Africa because it works. Composted manure is added to the holes well in advance of the rainy season. Then after a good rain, you can plant- usually millet or sorghum and about 3 seeds per hole. 

100 hectares is about 247.1 acres. It's critical to be
able to implement these systems at this large scale.

That is essentially the system. Weeding is minimal because weeds only grow within the Zai holes…but it's important. When the millet is about calf-high, we bring in animals, who eat down the plants and then they come back more vigorous. The grains are the first year rotation, then the second year, it's des legumineuses: sesame, beans or peanuts to fix nitrogen. (I'd always wondered about sesame the plant, I only hear about the seed and the oil. Photo on the right is the dried seed pod from the plant. I thought it was beautiful.) After the nitrogen fixing round, the third year the field is left fallow to rest and regenerate. Fourth year, back to grains. It's important to leave behind the stalks once grains are harvested, these provide ground cover and organic material as they break down- which you can see in the photo below. With each year's rotation, you add composted manure -fumier- to the Zai holes- to replace the nutrients you took from the soil.  Then during the dry season, animals come through added more nutrients and eating what they can- which helps because food gets scarce during the time furthest from the rains.

Mady and I moving electric fence for cattle in a millet field during the dry season. 

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