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Production functions for apple orchard systems in the Okanagan valley of British Columbia

University of British Columbia

The basic objective of this thesis was to estimate disaggregated production functions for apple orchard systems in the Okanagan area of British Columbia. Because of the complexity of the production process and relatively recent technological developments, it was considered that production function estimation would be useful in aiding resource allocation. In order to be useful at the farm level it was necessary that the model incorporate factors of major importance in managerial decisions. Particular emphasis was placed on orchard establishment alternatives relating to the planting concept which included density, tree design and rootstock. Weather variables and interactions were also of major interest. The conceptual model was therefore highly disaggregated and included a large number of variables. Measurement of these variables was based on data obtained from an orchard survey plus records of experimental blocks at the Summerland Research Station. Problems in estimation arose due to the large number of explanatory variables. Two basic methods were used in dealing with these problems. The first involved a sequential testing procedure whereby groups of explanatory variables were entered separately into multiple regressions with yield per acre as the dependent variable. Subsets of each group were retained in the final model. The second method involved the estimation of separate functions for each tree-size category, thereby eliminating rootstock and related interactions as explanatory variables. In both cases weather variables were preselected based on the results of a separately estimated regional model which used only weather influences as explanatory variables. The statistical results showed that the production function could best be represented by separate functions for each tree-size category. Interactions proved to be significant and added considerable explanatory power to the model. Weather variables were also significant, especially at the regional level where a large amount of variation in average yields could be explained by blossom time influences. The estimated production functions were used to predict yield streams over a 20 year period. It was shown under certain conditions that the potential exists for much higher yields and profits from high density systems than from low density systems. The functions also showed the higher variability of yields from high density systems and greater responsiveness to variable inputs and exogenous factors, implying that a greater management effort is required in their operation. Other applications of the production functions were discussed including possibilities of predicting total harvest volume from observed blossom time weather variables, evaluation of weather related technology, and directions of future scientific and economic research.

Text

2010-02-24

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http://hdl.handle.net/2429/20843

Agricultural Economics

University of British Columbia

Graduate