MODIFICATION OF MATURE KIWIFRUIT ROOT SYSTEMS DUE TO WINTER TIME WATERLOGGING CONDITIONS

The study was aimed to describe of the root system morphology of mature plants grown on a field were a water table gradient was maintained during the winter time. The vineyard was established in 1984 and the trial ended in the spring of 1992 with destructive observations. Two meter deep ditches were dug adjacent to vines subjected to different winter water table levels and summer water regimes. Roots were exposed by washing the soil profile with a hose, and the distribution of visible roots was assessed by counting the intercepts on a superimposed wire grid. A partial agreement existed with traditional RLD measurements done on soil cores, since different categories of roots were counted. Higher RLD were found in the spring with respect to the previous autumn. The maximum RLD was shifted upward under the influence of shallow water table conditions. The highest concentrations of roots in soil cores occurred in the shallowest soil laver. while grid counts were highest around 0.4 m depth.