Rapid Sap Nutrient Analysis Methods in Malus Domestica Borkh Cv. ‘Gala’

Abstract

Sap quick tests are well established in vegetable crops. However, there is less equivalent investigation for perennial crops, such as apple trees. Accessing the nutrient content, as opposed to the foliar analysis, would increase the opportunity of adjusting the fertilization, along the growing cycle. This work evaluates the relation between the NO 3 −, K + , Ca 2+ , Mg 2+ , PO 4 3and NH 4 + contents in apple petiole sap, measured with the RQflex ® test strips and laboratory methods to assess the possibility of using this tool with accuracy in in-situ sap analysis. Petiole samples were collected from six apple tree orchards, frozen and pressed. Dilution was mandatory for all nutrient determination, except NO 3 − . The dilution factor varied with the stage of the annual cycle. The levels of NO 3 − , K + , Mg 2+ , and Ca 2+ followed the same pattern during the growing cycle, with both methods. Regression analysis resulted in high determination coefficients for NO 3 − (R 2 = 0.85), K + (R 2 = 0.86), Mg 2+ (R 2 = 0.81) and Ca 2+ (R 2 = 0.95), between RQflex ® and laboratory methods. No equivalent relation was found for ammonium and phosphate determination. These tests can be useful tools for rational fertilization management, mainly in high-density apple orchards. The calcium content in 45 DAFB leaves correlated well with the calcium content in sap at the same timing.

Analysis of Petiole Sap Nutrients Using Rapid and Standard Methods and Its Relation to Leaf Analysis of Fertilized Malus domestica cv. Gala

“…The strips available from the supplier limit the number of analyzable ions. In apple petiole sap, high coefficients of determination (R 2 > 0.80) were achieved between the RQflex ® and the reference laboratory methods when determining N-NO 3 − , K + , Mg 2+ , and Ca 2+ using this rapid method [24]. In the former study, Pearson correlation values between the RQflex ® and laboratory methods were low for PO 4 3− and NH4 + .…”

“…If a petiole sap test can be performed reliably and inexpensively, it would be possible to monitor the nutritional status of an orchard during the phenological phases of the annual cycle or the nutritional status of trees in response to cultural practices. A previous study [24] was carried out in 2019 with the aim of assessing the quality of the relationships between the measured concentrations of ions in apple petiole sap, cv. Gala, using a rapid method RQflex ® reflectometer, and their concentrations were measured using the reference laboratory methods (ICP-OES and VIS-UV spectrophotometry).…”

Evaluation of real-time nutrient analysis of fertilized raspberry using petiole sap

“…In apple (Malus domestica Borkh cv. Red Gala), petiole sap Ca 2+ concentration correlated well with leaf tissue Ca concentration 28-147 days after full bloom with R 2 = 0.83 (Almeida et al, 2020). Nagarajah (1999) found a positive correlation between grape (cv.…”

System nutrient dynamics in orchards: a research roadmap for nutrient management in apple and kiwifruit. A review

“…A wide range of newer technologies are being developed and utilized to monitor orchard nutrient status and tailor fertilizer applications to achieve sustainable outcomes. Sap nutrient analysis has been widely used in vegetable crops and has been used to predict N in apple leaves (Almeida et al 2020). Imaging technologies are also being developed and used in fruit crops such as nondestructive leaf chlorophyll meters, which have been successfully used to assess leaf N status in a range of crops including apples (Lee et al 2019).…”