Irrigation Interval as a Factor in Sweet Corn Response to Salinity1

Abstract

AbstractShortening irrigation intervals with saline water is expected to reduce salinity damage by increasing the mean soil water content and thereby reducing the mean solute potential. Evidence is lacking in support of this hypothesis. This study tested the hypothesis by determining the interaction of irrigation water salinity and irrigation interval on sweet corn (Zea maysL. var. Jubilee) growth, yield, and water uptake. The field experiment consisted of 3.5, 7‐, 14‐, and 21‐day irrigation intervals and irrigation water salinities, ECl, of 1.7, 4.0, 5.3, 7.9, and 10.2 dS/m in a factorial design using regression analysis. The soil was a Calcic Haploxeralf. The amount of water at each irrigation was applied to replenish the soil water deficit as measured with the neutron scattering method. The regression of absolute yield on mean electrical conductivity (EC) of the soil saturation extract, EC, showed a steeper yield decrease with increasing EC, for the 3.5day than for the 75‐, 14‐, and 21‐day intervals. On the other hand, the relative yield, Y, response to salinity showed the same benefit of shortening the irrigation interval with saline as with nonsaline water. This lack of interaction on relative yield was due to an increase in mean ECe. from 4.4 to 5.4 dS/m as irrigation interval was shortened from 21 to 3.5 days. LeafCl−and Na+content tripled from 11.2 and 0.43 to 37.4 and 1.14 g/kg dry matter, respectively. The K+content increased from 19.4 to 26.4 g/kg, while the Ca content was unaffected as ECl, increased from 1.7 to 10.2 dS/m.