In 1979–1980, Ca, Mg, and K were measured in soil, leaf and fruit samples from 48 ’Starkrimson Red Delicious’ (Malus domestica Bork.) and 48 ’Summerland Red McIntosh’ (Malus domestica Bork.) apple trees located in 16 Okanagan orchards from Osoyoos to Vernon. The relationship Ca>Mg>K was generally found in the soils examined although, for nine sites, soil Mg content comprised from 5 to 10% of exchangeable bases while for 15 sites soil K exceeded 10% of exchangeable bases. The ’Delicious’ trees accumulated higher leaf Ca, Mg, and K and higher fruit Ca and K compared to ’McIntosh’ on a similar range of soils. A significant correlation between ’McIntosh’ leaf and soil Mg (expressed as a percent of exchangeable bases) was found in the 2 yr of the study. No direct positive plant-soil relationships were found for Ca or K. Significant negative correlations were measured in both years between soil Ca (expressed as a percent of bases) and leaf Mg for both cultivars, and between leaf Ca and K and between leaf K and Mg for ’Delicious.’ The results emphasized the importance of balanced orchard cation nutrition, particularly with respect to local soil Mg.
THE EFFECT OF POST PLANT SOIL SOLARIZATION ON BLACK ROT OF 'CARLOS' MUSCADINE GRAPE