Determining a Crop Production Function for Corn as Influenced by Irrigation and Salinity Levels

Production functions were generated for dry matter and grain yields of corn, A continuous variable plot design replicated four times was established in the spring of 1974 in Vernal, Utah. Each replication included ten salt treatments and twenty irrigation levels. The salt treatments resulted in an average root zone salinity ranging from 2 . 7 to 14.9 mmho s/cm. Irrigation levels ranged from 4.2 to 45.0cm of water applied. Dry matter (Kg/ha) yield showed an 83 percent reduction over the range of salt applied and a 52 percent reduction over the range of water applied. Grain yield declined 96 and 64 percent over the range of salt and water applied, respectively . Salinity sensors produced results corresponding closely to measurements taken from the saturation extract of soil samples . Thermocouple psychrometers and a four probe resistivity meter produced results inconsistant with those of the soil samples.