Agriculture Reference
In-Depth Information
lasting increase in agricultural productivity, as plant nutrients are also constraining
productivity in these regions. Straw production will be too low without fertilizer,
making it impossible for the farmers to retain the straw as a mulch. Less tillage will
make the conditions better for weeds, particularly the perennial weeds. Use of her-
bicides is therefore needed especially on larger farms. It is therefore difficult to pro-
mote CA as a low-input system. CA development should therefore be accompanied
by measures to increase the availability of fertilizer and herbicides.
CA has too often been promoted as a pure technological approach to agricul-
ture development. CA technologies have been demonstrated to the farmers, and CA
equipment has been distributed. None of the development organizations have sys-
tematically worked on integrating livestock into CA development. This is a vital
issue, as livestock grazing is the primary reason why it is difficult for farmers to
practice the principle of mulching in CA. It is only possible to practice mulching
if controlled grazing is practiced. Lack of fodder is the primary reason why free
grazing is practiced, and there is therefore a need to improve fodder production if
mulch-based systems are promoted. This can be in the form of increased straw pro-
duction, planting of fodder trees, or hay making. Improved grazing will also require
that there are local institutions in place that can deal with conflicts that may occur
in relation to improved grazing management. Development of CA may also make it
possible to change the composition of the livestock from oxen to more productive
milk or meat production animals, as there is less need for animal traction in CA. A
change from plowing to ripping was found to reduce the need for animal traction
by 75% in Zambia. CA development initiatives should therefore, in the future, also
take livestock development into consideration and focus on issues related to fodder
production, grazing management, and zero grazing of animals.
Agriculture polices have also often frequently worked against the development of
CA. A particular issue is the support to maize production in many countries in south-
ern Africa. Hybrid seeds and fertilizer have often been distributed through extension
packages, and farmers can sell the maize at a guaranteed minimum price. This has
stimulated farmers to practice maize monocropping, making it less interesting for
them to practice rotation as recommended in CA.
Papers critical to CA have claimed that CA increases a farmer's labor burden,
gives no yield benefit, increases weed infestation, and has limited effects on soil
properties (Giller et al. 2009). However, this chapter shows that it is difficult to make
general statements on how CA works. Often there is a yield benefit of CA, but the
results are variable depending on the methods practiced and the agroecological
conditions. More research is clearly needed to identify under which conditions CA
works and what the best practice of CA is. This is particularly important in Africa,
as CA here is in the early stages of development.
REFERENCES
Araya, T., W.M. Cornelis, J. Nyssen et al. 2012. Medium-term effects of conservation agri-
culture based cropping systems for sustainable soil and water management and crop
productivity in the Ethiopian highlands.
Field Crop Res
132:53-62.
