ISHS Acta Horticulturae 106: Symposium on Computers in Greenhouse Climate Control
ECONOMIC ASPECTS OF GROWTH REGULATION BY CLIMATE CONTROL |
| Author: | B. Bögemann |
| Abstract:
In horticulture, economic production models do not satisfy as they do not blueprint the real production process. On the other hand, biologic growth models do not sufficiently consider economic aspects. From the economic point of view the connection between both, the economic and the biologic submodel has to be searched for. Some elements of the economic submodel do not affect the growth process and can be dealt with separately. E.g. transportation activities (during production or after harvest) in general do not influence plant growth although transportation requiring labour, time and financial resources is a fairly important economic scope. Thus, indeed, only model components referring to both spheres are pertinent to our consideration. For economists, three kinds of relations are relevant:
a) marks the best factor combination; b) characterises the best input of this combination to obtain a certain output (the best output obtainable by a certain input respectively); c) shows the best production program. If in reality, a possibility of choice exists (i.e. a variability in these relations) then a model must be able to take it into consideration, i.e. it must reflect grower's degree of freedom. Obviously, factors and products cannot be described by one dimension. Besides quantity quality and time are important. E.g. a grower does not only want to provide a certain amount of a crop, but also with a certain qualification and at a fixed time (with a fixed period respectively); he has to take into consideration the next crop to be grown on the same area; he can decide on variety and planting time, and on greenhouse temperature at any time of the production period, etc. Whenever the application of any factor at any time affects quantity, quality or harvest time of a crop, the model should be able to show the consequences of this decision. Decision variables need decision rules. Degrees of freedom referring to the input of factors or the output of products indicate the producers's capability of choosing among them. Thus objective variables representing the entrepreneur's economic (or even non-economic?) goals have to be installed. Similar to factors and products, objectives do not consist of only one variable; nor profit maximising neither energy input minimising sufficiently explain producer's goals. Other aspects (e.g. | |
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