The Gatekeeper Series of the Sustainable Agriculture Programme is produced by the Interna-
tional Institutefor Environment and Development to highlight key topics in the field of sustainable
agriculture. The Series is aimed at policy makers, researchers, planners and extension workers
in government and non-government organizations worldwide. Each paper reviews a selected
issue of contemporary importance and draws preliminary conclusions of relevance to develop-
ment activities. References are provided to important sources and background material. The
Swedish International Development Authority and the Ford Foundation fund the series.

John M. Kerr is an economist with Winrock International InstituteforAgricultural Development,
based at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT),
Patancheru, Hyderabad, Andhra Pradesh India; and N.K. Sanghi is the Zonal Coordinator
(Andhra Pradesh and Maharashtra)for the Lab-to-Land Program, Division of Extension, Indian
Councilfor Agricultural Research, based at the Central Research Institute for Dryland Agricul-
ture (CRIDA), Hyderabad, India.

1992

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