Qj, ,, W,, Z ,, X,, 0 for all i,j,k,m, and 1,.


 The optimal solution to this model provides the equilibrium consumption of each

commodity in every month in each demand region (Qjk), the optimal level of shipments between

each supply area and each demand area by commodity and month (Xji,), the optimal production

of each cropping system by production area (W? and the quantity of each commodity produced

in each supply region by month (Za). The optimal dual solution provides market clearing

prices in each demand area by month and commodity.

 This model is a variant of the spatial equilibrium model presented by Takayama and

Judge (1971). It incorporates the use of a fixed proportions technology to generate supply.

Although the production functions used in the model follow the fixed proportions assumption,

the supply curves generated by the mold are not perfectly elastic. The upward sloping supply

curves result, in part, because of increasing transportation costs to market as production from

a particular supply region expands. This is the so-called implicit supply model as discussed by

McCarl and Spreen (1980). The model is simplified in that the inverse demand functions

incorporated into the model specify the price of each commodity is a function of its own quantity

alone. This simplifying assumption eliminates the integrability problem addressed by McCarl

and Spreen (1980), and Peters and Spreen (1989). This approach is often employed in multi-

commodity price endogenous models (Hazell and Norton 1986, p. 169).

 The other important simplification imposed on the model is that all parameters are

assumed to be non-stochastic. It is well-known that per acre yields of fresh vegetable crops are


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