Reviews of productivity increases in Africa reveal that the largest improvements occurred in sole crop fields. These findings are in line with the global model of increased specialization to increase productivity, implicitly suggesting that the transition from diversified systems to sole cropping appears an effective development pathway to enhance productivity. Specialized farming systems are likely to add much value to agriculture, contribute to food production and help to develop internationally competitive systems. In such systems all measures are fine-tuned in time and space to the specific needs of that particular crop, and high yields of crops per unit area can be obtained. Also, labour productivity can be greatly enhanced, as available technologies are geared towards this aim. Hence, much of the improvements can be obtained through the adaptation and adoption of technologies 'on the shelf'.
Sole crops or cropping systems with few specialized crops are not necessarily the only answer, and in Africa such specialization is much less appropriate than in other continents. It is unlikely that the transformation towards specialization will occur within one generation for almost 90 percent of the African farmers currently are engaged in diversified production systems. The preferred path is to exploit the advantages of diversified systems by stepwise upgrading and improving productivity. Diversified systems have developed in an environment of risk aversion where rainfed agriculture prevails, an erratic character of rainfall occurs, and (supplementary) irrigation is rare. There are good reasons to take Africa along a more diversified path of modernization than was seen in Asia in the 1970s and Europe in the 1950s.
The complex mixtures of crops and animals have to be taken as the benchmark when seeking opportunities for improvement (Landais and Lhoste, 1990). For instance, more effective use of natural resources (e.g., light and water) and added resources (e.g., fertilizer) can raise productivity of the entire system, because of optimized sharing of resources by the various crops or crop-livestock systems over time and space. It is more difficult to derive best technical means for diversified systems than for sole crop systems. Efficiency, efficacy and productivity at farming systems level may require measures and means that are not maximizing output of one specialized crop. The technologies described above require specific adaptation to make them appropriate for the various systems in Africa.
Members of the IAC