Rates and patterns of water from an oxisol of the "cerrados" of Brazil by corn crop

Abstract

A study was carried out under irrigation, during the dry season of 1977, on water uptake characteristics of corn (Zea mays L.) (cv. C-111 X) in an oxisol (LVE) of the Cerrado region. Rates of corn water uptake in different soil layers were determined by considering soil sample weight differences and upward or downward fluxes at different time intervals. It was observed that, in general, high population densities up to 80.000 pl/ha withdrew more soil water than the 20.000 pl/ha densities which is attributed to the higher root density shown by higher plant populations. Most of soil water was extracted from the 0 – 20 cm soil layer (40 - 45%). Average upward or downward water fluxes throughout the experiment can be considered of small importance (0.33 - 0.66 mm/day^-1), which is explained by the drastic decrease in hidraulic conductivity as soil water content diminishes. Soil water depletion in the 0 – 60 cm soil layer (containing 85 - 90% of available water) would occur after eight to thirteen days for population of 80,000 and 20,000 pl/ha, respectively, showing that the manipulation of plant density can be an important management tool to mitigate drought in the Cerrados.