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Advisor(s)
Abstract(s)
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 NO3
−, K+, Ca2+, Mg2+, PO4
3- and NH4
+
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 NO3
−. The dilution factor varied with the stage of the annual
cycle. The levels of NO3
−, K+, Mg2+, and Ca2+ followed the same pattern
during the growing cycle, with both methods. Regression analysis resulted in
high determination coefficients for NO3
− (R2 = 0.85), K+ (R2 = 0.86), Mg2+
(R2 = 0.81) and Ca2+ (R2 = 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
Description
Keywords
calcium magnesium nitrate potassium diagnostic methods
Pedagogical Context
Citation
Patrícia da Costa Almeida, Cristina Oliveira, Mariana Mota & Henrique Ribeiro (2020) Rapid Sap Nutrient Analysis Methods in Malus Domestica Borkh Cv. ‘Gala’, Communications in Soil Science and Plant Analysis, 51:12, 1693-1706
Publisher
Taylor & Francis