Diagnostic leaf analysis for stone fruit. 6. Apricot

Abstract

Changes in the nutrient-element composition of leaves of 'Trevatt' apricot were measured monthly during the 1971-72 and 1972-73 seasons in New South Wales. The rate of change of leaf composition was least during January-February. Thus, leaf composition standards should be based on January- February samples and diagnostic sampling should be confined to this period where possible. Correction factors for adjusting the composition of early or late samples back to January 31 levels, were calculated from polynomials with time fitted to the leaf composition data. A survey of the leaf composition of well-managed 'Trevatt' apricot orchards was conducted each January from 1971 to 1973 in New South Wales and Victoria. Percentages of orchards classified as low to deficient (-), and high to excess (+) for various nutrients were as follows : New South Wales (averages of 1971 to 1973) N -41 ; P +37; K +49; Mg +56; Fe +1 9 ; Zn -18. Victoria (averages of 1972 and 1973) N -21 and +32; K +10; Fe -35; Mn +17; Zn -20.