Agriculture Reference
In-Depth Information
Africa has been promoted by actors such as the FAO, the African Tillage Network
(ATN), the Department for Development (United Kingdom), the Norwegian Agency
for Development Cooperation, and the Conservation Farming Unit (CFU). CA has
also become one of the national strategies for promoting agricultural development
in Zambia. There are many reasons for this increasing interest in CA in Africa. The
success of CA in South America has obviously been an inspiration for also promot-
ing CA on other continents. Yields have been stagnant in sub-Saharan Africa, and
key actors like FAO and the ATN see CA as a new approach that can bring about
agricultural development. However, it is not possible to transfer the CA methods
used in South America directly to Africa as the socioeconomic and environmen-
tal conditions are different. CA in South America is mainly a mechanized form
of agriculture, making it difficult to transfer this type of CA directly to the small-
scale farmers in Africa. CA has also been promoted as an approach in mitigation of
greenhouse gases from agriculture and as an adaptation to climate change (Corsi et
al. 2012).
The introduction of CA in Africa has been seriously criticized in recent years
(Giller et al. 2009) on grounds that it can increase a farmer's labor burden, it gives
no yield benefit, it increases weed infestation, it has limited effects on soil organic
matter, and there is unavailability of key input for practicing CA.
This chapter will summarize experience with the introduction of CA in Zambia,
Malawi, and Ethiopia, and will also draw on results from neighboring countries. The
focus is on these countries as they represent contrasting environments with regard
to previous tillage systems and ecological conditions, and because of the author's
experience in CA research and development in these countries.
10.2 VARIATIONS IN CA METHODS ACROSS AFRICA
CA has not been introduced in a uniform way in Africa, and there are clear dif-
ferences in approach between neighboring countries such as Zambia and Malawi.
However, the agroecological and socioeconomic conditions vary greatly across
Africa, and it may therefore make sense to use different approaches.
Tillage by use of the plow and animal traction was introduced in Zambia during
the colonial time. Use of the moldboard plow with oxen traction is the dominant
form of tillage in southern Zambia as the people in southern Zambia are livestock
keepers. Tillage by use of the hoe is more practiced in eastern Zambia. The CFU has
been a major actor in promoting conservation agriculture in Zambia. The emphasis
has been on establishing basins that are 30 cm long and 15 cm wide and 15-20 cm
deep (Umar et al. 2011). The basins are preferably dug with a chaka hoe, which is
a hoe that is heavier and has a narrower blade than the traditional hoe. The spacing
between the basins is 90 × 70 cm. Basins are also used in CA farming in Zimbabwe.
However, the basins here are smaller than those used in Zambia as the size is in the
order of 15 × 15 cm with a depth of 15-20 cm (Mazvimavi and Twomlow 2009). The
other form of tillage promoted in Zambia is ripping. This is a form of tillage that is
gaining popularity mainly because of its labor-saving effect. The soil is ripped to a
depth of 20 cm. One reason for introducing both basins and ripping is, according
to the CFU, to break the plow pan. However, a soil survey has not confirmed that