Figure 9. Making compost. Source: ECHO West Africa Impact Center Staff
The decline or even loss of soil fertility is the major challenge faced by more and more farmers around the world in general and especially those in sub-Saharan Africa. Many causes, mainly anthropogenic, are at the origin of this situation. Despite the massive use of chemical fertilizers through price subsidy programs, many farmers are showing that their agricultural yields are continuously decreasing despite a constant increase in the quantities of fertilizers in their fields.
There is, however, a simple, natural, and effective way of restoring fertility to the land. It is composting which is an exceptional alternative to chemical fertilizers and which increases the level of organic nutrients of the soil while helping to restore the natural biotic balance of the soil.
Among the multiplicity of composting methods, we will present you the compost of aerobic compost piles. This ancient technique consists of a type of man-made fermentation which allows it to manage the cycles of organic matter. By promoting this composting technique, ECHO's Regional Impact Center for West Africa wanted to consider two aspects that characterize it: precocity and simplicity (accessibility). From the point of view of precocity, the composting technique promoted makes it possible to have access to compost in 21 days, perfectly mature and immediately usable. In terms of simplicity, all the elements necessary for making this compost are available and accessible in any farmer environment and require no expenditures.
How to make compost
1. Components
|
Ingredient |
Percentage |
|
Green matter (green leaves from any tree or grass, or any dried green leaves ie green cut and dried and preserved in shade) |
45% |
|
Dry matter: grain stalks, thatch, dry and dead leaves, straw, etc. |
40% |
|
Dry woody material: dry branches (small diameter ≤ 3 cm), dry cotton stems, dry corn cobs, peanut shells, wood shavings, cardboard leftovers, dry tree barks, etc. |
5% |
|
Manure from any animal species |
10% |
|
Water |
about 800 L |
Please Note. : In the absence of manure, this can be replaced by legumes (peanut, cowpea, voandzou, leucaena leucocephala, gliricidia sepium, albizia lebeck, etc.). The required proportion is 20% of the compost pile volume.
2. Preparation
For a quantity of compost sufficient for half a hectare, it is necessary to arrange a space of 2m x 2m x 2m or a space that can contain a volume of 8 m3. However, it is recommended to double the ground surface in order to turn the pile upside down. The place that the compost is manufactured must be shaded and protected from the sun's rays. It should be as close as possible to a water source (pond, stream, puddle, well, borehole, etc.).
After first assembling the various components, the actual work will consist in alternating layers of 20 cm thick; each of dry matter, green matter, dry woody, and manure. This sequence is repeated until all the components have been exhausted. Each layer must be pre-soaked in water before being stacked, with the exception of the manure which will be spread directly. Before any new layer is applied, the previous one must be abundantly watered. The particularity of this compost is that it must not undergo any pressure or compaction, nor be covered by any tarpaulin.
Figure 10. Making copmost. Source: ECHO West Africa Impact Center Staff
Once the compilation is completed the pile is turned over every 3 days (for a total of seven times) so that on the 21st day it is ready. In the meantime, it is necessary to control the temperature (which must be between 55°C and 68°C) and the humidity of the pile in order to avoid killing certain beneficial microorganisms and to avoid losing excess carbon. The temperature control is done by placing a metal rod in the center of the pile for 5 to 10 minutes and trying to hold it with your hand for 5 seconds after removal. If it is difficult to hold the wand, it means that the temperature is above 70°C and the heap must be turned over and watered. With regard to the humidity, control it consists in squeezing the compost in your hand, if water passes between the fingers of the hand that is a sign of high humidity.If the ball remains firm without water flow after opening the hand it means that the moisture is good. Finally if after opening your hand, the ball breaks up, the compost is too dry and requires watering. It must also be ensured at each turn that the outer parts of the pile are placed in the center and that the center of the pile (which is hot) is outside so that all parts of the pile undergo the same temperature at a given point in the cycle.
Watering during the turning only requires between 20 to 30 liters of water and is done once the pile has been completely turned over. After the 21st day the compost should have a rich smell and can now be sifted and cleared of its coarse undecomposed elements. It can then be stored for several years.
This compost can be carried out at any time of the year provided it is protected from heavy rainwater by a roof. For the optimization of the effects of the compost, the method of using fertility stations is preferred to that of direct spreading on the field.
Compost has may effects on the structure of the soil (increase in aggregates which facilitates good root penetration, better permeability to water and air, better water retention). Compost mineralization provides plant-assimilable substances. It's chemical caracteristics buffers or can even correct soil pH. And it's living components increases biological activity of the soil due to microorganism populations which are part of the compost. Compost offers farmers the best prospects for restoring soil fertility and deserves to be promoted and popularized to the level of its many advantages and quality.