Irrigation in southern Africa: success or failure

Despite widespread recognition of the importance of irrigation development in southern Africa, no comprehensive examination exists on the performance of past irrigation schemes in the region. This paper systematically examines existing literature on irrigation schemes in southern Africa in order to: (i) determine the proportion that can be considered successful; and (ii) identify and rank factors that explain variation in performance. The results indicate that some 59% of irrigation schemes in southern Africa can be considered successful. Factors associated with successful performance include: management style, irrigation method, crop mix, type of financier and geography. The levels of success identified through this review validate calls to increase the irrigated area in southern Africa. These results nonetheless highlight opportunities to strengthen the way in which future irrigation schemes are undertaken. In particular, these results may call for increased use of sprinkler irrigation and reduced use of flood irrigation with pumping. The results also suggest more investment could be channelled into schemes focused on maize–vegetable crop rotations and sugar cane, and caution applied to government management of schemes

Climate Change and Adaptation: The Case of Nigerian Agriculture

The present research offers an economic assessment of climate change impacts on the four major crop families characterizing Nigerian agriculture. The evaluation is performed by shocking land productivity in a computable general equilibrium model tailored to replicate Nigerian economic development up to 2050. The detail of land uses in the model has been increased by differentiating land types per agro-ecological zones. Uncertainty about future climate is captured, using, as inputs, yield changes computed by a crop model under ten general circulation models runs. Climate change turns out to be negative for Nigeria in the medium term, with production losses and increase in crop prices, higher food dependency on foreign imports, and GDP losses in all the simulations after 2025. In a second part of the paper, a cost effectiveness analysis of adaptation in Nigerian agriculture is conducted. The adaptation practices considered are a mix of cheaper "soft measures" and more costly "hard" irrigation expansion. The main result is that the cost effectiveness of the whole package depends crucially on the possibility of implementing adaptation by exploiting low-cost opportunities which show a benefit-cost ratio larger than one in all the climate regimes

Soil degradation as a reason for inadequate human nutrition

Food security, Hidden hunger, Desertification, Soil quality, Sustainable agriculture,