Root distribution of kiwifruit as influenced by winter water-table level and irrigation regime

Root length density (RLD) of 6-year-old kiwifruit (Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson) vines was determined in the spring and at end of the irrigation season, in a pIanting subjected to a gradient of winter water-table levels ranging between O and 2.0 m. Two irrigation regimes were also imposed, providing 50 and 125% of the estimated maximum crop evapotranspiration (ETc). A shallow water-table caused much higher RLD dose to the stem, but values in the autumn were similar to the controI. Contour plots of RLD generated by a Kriging procedure, showed steeper downward and outward gradients for pIants grown under shallow water -table conditions, whereas control plants featured a more expansive root system. RLD was increased by the 125% ETc treatmentatall depths and distances from the vine