Agriculture Reference
In-Depth Information
FIGURE 10.2
Planting basins as practiced in Zambia.
of the plough” (McCann 1995), and oxen tillage is deeply rooted in the culture of
rural Ethiopians. The ard does not turn the soil as the moldboard plow does, but
rather breaks up a narrow strip of soil. The soil is tilled up to six times depending
on the type of crop that is grown (Aune et al. 2001). This tillage system is under
increasing pressure, as it is demanding for the farmers to keep the number of animals
necessary for maintaining the system. It has been shown that the farmers constantly
need to keep 10 animals to always have access to two oxen (McCann 1995). The
animals needed to maintain the system are calves, oxen under training, and cows to
ensure reproduction of the system. As farm size in Ethiopia has been shrinking, it is
increasingly difficult to support this livestock system. Not all farmers have access to
a pair of oxen, and farmers without oxen often have to pay 50% of the harvest to get
the land plowed (Aune et al. 2001). The man who plows will, in addition, take the
straw. New forms of tillage systems have been introduced in Ethiopia. This includes
direct sowing with and without mulch, and different reduced tillage methods.
In the sandy soils of the drylands of West Africa, the seeds are often sown
directly. However, this form of tillage is seldom called CA although direct sowing
is practiced. Planting basins (called “zai” in Burkina Faso) are also used in West
Africa as a method of soil and water conservation and as a method of rehabilitating
degraded lands (Sawadogo 2011). These planting basins have similar dimensions as
the planting basins in Zambia (Figure 10.2). Organic manure is often added to the
planting basins to increase soil fertility.
10.2.1
CA E
ffECts
on
Y
iElds
When assessing the yield benefits from CA, it is necessary to differentiate between
the effects of the different components of CA and the combined effect of the CA
component on yield. The effect of CA on yields is variable depending on how it is
