Mayze relative production and leaf contents of nitrogen, phosphorus, sulfur and chlorine as a function of the soil salinity.

Abstract

The concentration of salts in the soil solution can be a decisive factor in the productivity of crops, since its action may extend from a simple decrease in the soil water potential to a cellular injury caused by an oxidative stress in the plant. The effects of the soil salinity on either relative production of the mayze variety UFV 100 and the leaf contents of nitrogen, phosphorus and sulfur, as well as their relationships with chlorine were evaluated in an experiment conducted with drainage lysimeters under greenhouse conditions, which was set up under an entirely randomized design with seven treatments: one irrigated with fresh water and no leaching and six irrigated with saline water of 1.2 dS.m-1 with leaching fractions of 40; 30; 20; 15; 10 and 5% of the applied irrigation depth, and three replicates. The chlorine contents in the leaves were increased from 120 days after planting (DAP), whereas the contents of nitrogen and phosphorus were reduced from 90 and 120 DAP, and those of sulfur from 120 DAP on. The relationships Cl-/N, Cl-/P, Cl-/S were increased from 120 DAP, (60 and 120) DAP and (60; 90 and 120) DAP, respectively. The mayze variety UFVM 100 showed to be sensitive to the soil salinity and the relative production showed a decrease of 15.68% with unit increments of the soil salinity above 1.70 dS.m-1 (threshold salinity).