No abstract

The production of perennial crops involves planting, removal, yield, and time dimensions not similarly encountered in annual crops. A model is developed to provide a structural base for estimating response relationships that encompass these dimensions. The model rests on assumptions of rational producer behavior which takes account of possible actions of other producers and of the aggregate effect of these actions on total production and profits. Because important data series often are not available, modifications of the basic model are suggested to facilitate estimation within a more restricted empirical framework. The model is illustrated by an application to asparagus, a perennial vegetable crop. I N VIEW OF the rather extensive volume of literature pertaining to agricultural supply response, the special problems associated with formulating supply models for perennial crops have until very recently received surprisingly little attention.' Prior to 1960 there were almost no attempts to estimate such supply functions.> Some new ground was broken in a 1962 study by French and Bressler [14] which developed supply response for lemons in terms of new planting and removal relationships. This type of model developmen t, with modifications or simplifications, was later applied by other researchers to United States apples [8], cherries [11], pears [24], and tung nuts [18], with varying success. Much of the recent research on perennial crop supply response has related to commodities typically produced in less developed areas-mainly coffee, cocoa, and rubber. Studies by Arak [2, 3], Bateman [4,5], and Behrman [6] in particular have made significant advances in formulating perennial crop supply models, with special reference to these tropical or warm area commodities.

services-actually operate. Incorporation of modifications in the conventional theory then provides a more workable base for studies of cost and efficiency.

No abstract

Technical assistance is provided to country governments as part of international development programmes to support policymaking or strengthen state capability. This article presents the conceptual evolution of ‘technical assistance’ linked to capacity development, starting with programmes aiming exclusively to enhance individual capacity in the 1950s to 1970s and progressing to complex systems approaches in the past ten years. It also presents some of the frequent challenges in designing and implementing technical assistance, drawing from the existing literature and the authors’ experience in international development. The article summarises the latest thinking about delivering more effective development, including the adaptive management practices and the initiatives to strengthen evidence about what works. Finally, we complement this article with a follow-up open letter reflecting on the current policy options and opportunities for change.