Usage of Shoot Analyses to Assess Early-Season Nutritional Status of Apple Trees

Mid-summer leaf analyses are commonly used as the standard method worldwide to assess the nutritional status of fruit trees. However, the analyses performed at this period yield information only about current nutritional status of the trees. Several physiological processes influencing yield and quality take place early in spring. It was reported in previous studies that dormant-season shoot analyses for some nutrients may reliably be used to assess early-season nutritional status of peach trees.The present study was conducted with the shoot samples taken in dormant-season of 150 apple orchards from Isparta region during the years 2010 and 2011. Shoot samples were taken 15 days before full bloom stage and samples were subjected to nutrient analyses. Reference values for each nutrient were indicated as 25 and 75% of the resultant values. The shoot reference values for N, P, K, Ca, Mg, Fe, Mn, Zn and B were respectively observed as 0.66–0.82%, 0.12–0.15%, 0.37–0.45%, 0.84–1.24%, 0.11–0.16%, 24.55–32.24?ppm, 11.12–17.55?ppm, 12.96–21.90?ppm and 13.33–16.00?ppm. To check the reliability of shoot analyses, leaf samples were taken from the same orchards in 7 different periods until mid-vegetation season and correlations between nutrient contents of shoots and nutrient contents of leaves taken in all periods were investigated. Significant correlations were observed between N, P, K, Mg, Mn and B contents of shoots and leaves. Therefore, it was concluded that early-season shoot N, P, K, Mg, Mn and B analyses could reliably be used to assess nutritional status of apple trees.