Eric W. Crawford

Informing Food Security Decisions in Africa: Empirical Analysis and Policy Dialogue

Discussions of economic and agricultural development in Africa have focused heavily in recent years on structural adjustment, i.e., basic policy changes aimed at allowing international and domestic markets to play a greater role in coordinating national economic activities. Often these structural adjustments and accompanying policies aimed at improving economic performance have been based on several implicit assumptions about how African food systems operate. Yet, for many countries little empirical information has been available to test these assumptions. Hence, designing policies too often becomes an exercise in planning without facts. This paper argues that not only is there a need to base food security and structural adjustment policies more firmly on empirical information, but that the process by which the information is obtained is as important as the information itself. Agricultural economists and other social scientists can, and increasingly should, design policy research in Africa in ways that simultaneously increase effective demand for empirical information as an input into the ongoing policy process and augment African capacity continually to inform policy deliberations. We illustrate the payoffs to such an approach by drawing on selected experience in several African countries (Weber).

Welfare effects of maize technologies in marginal and high potential regions of Kenya

This paper describes the findings of a study that used a multi-market model to assess the potential impact of improved maize technologies on the welfare of various types of rural and urban households in Kenya. The modelling results indicate that technologies developed for high potential regions are likely to have more profound aggregate impacts on maize production and lead to greater reductions in import demand (if prices are controlled) or maize prices (if maize prices are flexible). Technology adoption in high potential regions is likely to have substantially greater positive impacts on aggregate real incomes, but inferior income distributional outcomes compared to technology adoption in marginal regions.

The Sensitivity of Returns to Research Calculations to Supply Elasticity

Returns to research are thought to be robust under alternative supply elasticity assumptions. We show, both conceptually and numerically, how advances in approximating social benefits make returns to research sensitive to the supply elasticity. Despite this greater sensitivity, these advances retain conceptual and practical advantages. We make recommendations for dealing with the increased sensitivity. Copyright 2002, Oxford University Press.

Improving fertilizer recommendations for subsistance farmers in West Africa: The use of agro-economic analysis of on-farm trials

A large number of zero, half and full rate fertilizer trials were conducted on-farm in Southern Senegal with rainfed lowland rice (n = 24), maize (n = 48), and groundnuts (n = 18). Trial sites were located according to farmer selected criteria: soil texture in the case of rice; compound garden versus outer field in the case of maize; and, previous cropping history in the case of groundnuts. Quadratic fertilizer response curves using all the cases explained only 16–29% of the variance. Subsequent stratification of the fields by soil organic matter, texture, and pH permitted the identification of fertilizer responsive and non-responsive fields. Response curves using only the tests conducted on soils without a limiting constraint explained 36 to 47% of the variance. At half rate fertilization levels VCRs of 3.8 (maize), 5.8 (rice) and 6.9 (groundnuts) resulted. Within productive fields, level of weed control, percent barrenness and final stand at harvest explained much of the remaining variation in yields for rice (82%), maize (61%) and groundnuts (76%) respectively. Response curves were then used in an economic analysis to address on-farm fertilizer allocation issues. Based on survey results and field trial data, partial budgets for small and medium-sized farms were developed. This analysis showed marginal rates of return of 400 and 165 percent to half and full rate fertilization, respectively. This type of fertilizer validation program, conducted on farmer-selected sites, improved targeting of recommendations, and helped to identify agronomic practices that should result in reduced economic risk and increased fertilizer adoption by farmers.

A Multi-Year, Stochastic, Farm Simulation Model for Northern Nigeria: An Experimental Design Approach

The paper illustrates the use of experimental design in simulation modelling. Income growth prospects for small farms in northern Nigeria are examined under deterministic and stochastic conditions. A partial factorial design is employed to assess the impact on growth of resource endowment, stochastic yields and returns, consumption behavior, and enterprise opportunities. Analysis of variance on the deterministic results indicates that the key determinants of financial performance are stochastic events and family size and resource endowment. Capital accumulation under stochastic returns is slower than under fixed average returns. The value of a multi-year model is discussed.

An agro-economic analysis of field trials from a farming systems research perspective : weed control in rainfed lowland rice in Senegal

Using a farming systems approach, a multidisciplinary team in southern Senegal examined three strategies for weed control in rainfed lowland rice: use of herbicide; replacement of broadcast seeding by row seeding with mechanical seeders; and transplanting compared with direct seeding of rice. Thorough evaluation of the agronomic and economic benefits of these strategies for farmers was facilitated by supplementing the standard analysis of on-farm trials with multivariate analysis incorporating agronomic survey data to explain treatment effects better, and by considering technical and economic effects throughout the farming system. The agro-economic analysis led the team to conclude that: where soils are productive, herbicide use is a profitable investment; when converting to direct seeding, farmers should facilitate weeding by seeding in rows with a mechanical seeder; and transplanting should not be discouraged in areas where it is still feasible, since it is less time-consuming, fits in better with other farm activities and requires less fertilizer.

Research on Agricultural Systems: Accomplishments, Perspectives and Issues

The purpose of this book is to provide an overview of research on agricultural systems that is both broad and selective. The focus is broad, by covering approaches used in a number of disciplines, as well as in multidisciplinary studies, and by defining agricultural systems to include cropping systems, fanning systems, agricultural household systems, and agricultural systems at higher levels such as the agrarian system. The focus is selective by emphasizing key methods and ongoing debates, rather than attempting a comprehensive review of literature. Most previous reviews of research on agricultural systems have concentrated on a particular approach, eg farming systems research (FSR), including comparisons of anglophone and francophone variants of FSR, or on research conducted in specific geographical settings.