The effect of salinity on corn yield using the CERES-maize model

In most cases, when calculating soil water availability, only the water content is considered. The effect of salinity on the wilting point is neglected. The objective of this work is to use a simulation model (CERES-maize) in order to predict corn yields as a function of water salinity under several environmental, agrotechnical, and plant characteristics. A model is presented in which the wilting point is a function of the soil salt content. At high salinity, the water content at wilting point is higher than at low salinity, resulting in an insufficient amount of available water and, therefore, a reduced yield. The model was used to simulate several theoretical and experimental situations for forage corn and grain corn. Simulation results showed that nitrogen fertilization increases the salinity threshold value and the yield sensitivity (rate of yield reduction per unit of salinity). The also showed that forage corn is more sensitive to salinity than grain corn. If the soil is not leached, a heavier soil texture has a higher salinity threshold value. On the other hand, if the soil is leached, the soil texture has no influence on the salinity threshold value and the yield is less sensitive to salinity in sandy soils. The determination coefficient (r² = 0.75) indicated that the results of the simulations were in good agreement with the field data.