Untitled - CGIAR Impact

26 ECONOMIC CONSEQUENCES OF NEW RICE TECHNOLOGY
1. Conceptual model of potential yield and yield gap.
situations within a country. In this regard, I point out that a single value, i.e. one
specific level of potential yield and magnitude of yield gap, is not relevant to
many agroclimatic and soil conditions in the country. I suggest, therefore, that
the level of potential yield and the yield gap be situation specific, and that the
situation be classified by regions in terms of seasonal variation, soil variability,
and water regimes.
The Herdt-Wickham paper attempted an examination of the different water
regimes by season — upland, irrigated dry and wet season, and rainfed — but
the analysis that averaged all the situations to arrive at a single national potential
yield level and its corresponding gap does not satisfy the requirements of
research scientists, research administrators, policy makers, or rice farmers.
The method of measuring gap with respect to biological and economic factors
is not specific. Also, there exists a conflict between physical maximum
(national production) and economic optimum (profit considerations and rate
of return for individual farmers) in terms of production level.
Bangladesh experience. In both absolute and relative terms, the modern rice
varieties have spread less rapidly in Bangladesh than in the Philippines. Over a
10-year period the modern varieties spread to 15% of the total rice area of
Bangladesh (Table 1). No dramatic yield increase has been experienced, however,
although overall rice production recently increased.
Investigation of rice production to determine the yield potential of the
improved technology and to quantify the magnitude of the yield gap revealed
partial adoption of the improved technology. The potential yield levels of the