Table 2. Influence of corn price on MEY and net profit at two
 levels of fixed input costs. Calculations are based on
 functions shown in figure 1. Price of N is $0.30 per lb.


N Rate Corn price Cost/price MEYt Fixed Input Costs
lb/acre $/bu ratio bu/acre $200/acre $300/acre

 ---profit $/acre---

 219 1.00 0.30 233 -32.70 -132.70
 244 1.50 0.20 239 85.30 14.70
 256 2.00 0.15 241 205.20 105.20
 269 3.00 0.10 243 448.30 348.30
 269 4.00 0.08 243 691.30 591.30

 tUnder certain price structures MEY represents the minimum loss.
 Profit = (bu/acre x $/bu) (lb N/acre x $/lb N + other input
 costs).




 This report shows conclusively that MEY is inversely proportional

to the cost/price ratio for production of irrigated corn.

Furthermore, in production systems adequately described by the

function in figure 1, it is not profitable to add variable inputs

when the cost/price ratio is greater than 1.18 regardless of fixed

costs. Data are needed to develop regression models of yield as a

function of pesticide rates in order to define low input

sustainable agriculture (LISA).