Attachment A
	Agriculture

Linear Programming Model

The FARM-BUD model is a simple linear programming matrix. It has the general form:

Objective function:
Subject to constraints:

Where:

P_j = Price received per unit of output of crop (bushels,tons,etc)
Y_j = Yield per acre
c_j = Production costs per acre
X_j = Number of acres produced
a_ij = Technical coefficients describing the production processes
b_i = Available supply of inputs

The LP model maximizes net farm income (gross revenues minus costs of production) subject to physical, monetary, management, and efficiency constraints. The production capability of each typical farm is limited by the amount of land available, equipment complement, water supply, amount and type of farm production inputs such as fertilizer and chemicals, and a limited number of working hours in any given month.

LP models arrive at a solution by ranking the production processes in order of profitability. If a model is not constrained, it will pick the most profitable crop and put all available resources into that one crop. Generally, this result is not realistic. Therefore, the model is constrained so that a more realistic solution is given. The base LP model for this analysis replicates the acreage and cropping patterns shown in the payment capacity studies done for the districts.

A key assumption for the base LP model (No Action Alternative) is that the water supply available to each farm is sufficient for producing the stated yields. The assumed water supply equals the model's demand for irrigation water, calculated by multiplying the crop irrigation requirement by the number of acres for each crop. Irrigated corn requires 15 acre-inches per acre, soybeans need 10 acre-inches, full-production alfalfa needs 18 acre-inches, and newly established alfalfa needs 8 acre-inches.