The occurrence of water deficit during the maize crop cycle may affect the physiological processes of plants. The objective of this research was to evaluate alterations in the leaf conductance of maize plants, submitted to different soil tillage systems and water availability in the soil. A field experiment was carried out in the Estação Experimental Agronômica of the Universidade Federal do Rio Grande do Sul, in the summer season of 2002/03. The maize was cropped in no-tillage (NT) and conventional tillage (CT) systems, with full irrigation (I2) necessary to maintain the soil moisture close to the field capacity, partial irrigation (I1) corresponding to 41% of the water application in I2, and non-irrigation (I0). The measurements were taken at 10h and 13h (local time), in order to characterize the maximum and minimum leaf conductance, respectively. During the vegetative plant growing, the lowest values of either maximum and minimum leaf conductance occurred in the no-tillage system. However, since the maximum leaf area index was achieved (at tasseling stage), the maize plants cropped in no-tilt soil presented the highest leaf conductance, indicating a higher soil water availability in NT than in CT.
Zea mays; no-tillage; water deficit; leaf water potential
