Acceso usuarios
The effect of moisture tension and doses of phosphate fertilization on yield components of sweet corn A-7573 (Zea mays L.) hybrid, in a Calcium Vertisol were evaluated. Four levels of soil moisture tension, ranging from -5 to -80 kPa, and three levels of phosphate fertilization: 60, 80, and 100 kg ha-1 were studied. In order to evaluate the effect of the experimental treatments, plant growth, development, and yield were monitored. Treatments were distributed using the randomized complete block design (RCB) for divided plots of experimental units. ANOVA analysis indicated that the effects on more humid treatments (-5 and -30 kPa) were statistically equivalent, however were different from the effect of -55 kPa treatment, which in turn was statistically different from the effect of the driest treatment (p = 0.01). On the other hand, 80 and 100 kg ha-1 phosphate doses were statistically equal among them, but different from the lowest dose in almost all cases (p = 0.01), which suggests that 80 kg ha-1 P2O5 application is sufficient to satisfy the nutritional requirements of the A-7573 hybrid. Both stress caused by the lack of water and the one due to deficiency of phosphorus affect all variables under study, however none of them showed interaction between irrigation and fertilization treatments. Irrigation of sweet corn crop is advisable when soil moisture tension grows to -30 kPa at 0�30 cm depth and to apply a phosphate fertilization dose of 80 kg ha-1 is also recommended; using this management, sweet corn expected average length and fresh weight are 30.8 cm and 298 g, respectively, and their average yield is around 16.5 t ha-1. In accordance with regression equations obtained, the maximum values in the evaluated response variables are obtained for a rank from -14.4 to -22.2 kPa in soil moisture tension. The greater efficiency in the use of irrigation water for sweet corn was of 36 kg ha-1 for every millimetre laminate of watering applied, found in the -30 kPa treatment of soil moisture tension
