EFFECT OF P AND K FERTILISERS AND OF THE DATE OF SAMPLING ON THE CONCENTRATION OF MACRO AND MICRO-ELEMENTS IN THE LEAVES OF FOUR KIWI CULTIVARS

The effect of three levels of K (K₀ = 0.0, K₁ = 0.3 and K₂ = 0.9 kg of K₂O per tree) and three levels of P (P₀ = 0.0, P₁ = 0.4 and P₂ = 0.8 kg of P₂O₅ per tree) on the contents of macro and micro elements in the leaves of Monty, Bruno, Abbot and Hayward kiwi cultivars was studied in a complete randomized blocks experiment in the area of Chania Crete.
Four consecutive leaf samplings (May, June, July and August) were carried out for cultivar Monty while the other cvs were sampled in July and August only.
All samples were analyzed for N, P, K, Ca, Mg, B, Zn, Mn, Cu and Fe.

As it was expected potassium fertiliser application increased the content of K in the leaves.
This increase reached the 39.7 and 76.8 % of the concentration of K in the non fertilized with K controls in the late leaf sampling of late August while in earlier dates this effect was smaller.
Of the other elements determined potassium fertiliser depressed P and B in most cvs.
Phosphorus fertiliser did not increase the content of P in the leaves.
On the contrary at the third level of P fertiliser a small but consistent decrease of leaf P was found.

Worth to mention differences in the composition of leaves between the cvs were observed mainly with respect to K (the cv Hayward showing the higher contents and Monty the lower ones), Mg (the higher concentration of Mg was found in the cv Bruno and the lower in Hayward), B and N. The differences between cvs were not important with respect to Ca and Mn.
Leaf N, P, K and Cu percentage decreased while the one for Ca, Mg, B and Mn increased with leaf age.
Iron and Zn percentage changes were smaller and not consistent.

III International Symposium on Kiwifruit

M.H. Loupassaki, I.I. Androulakis, S.M. Lionakis

Actinidia chinensis, leaf analysis, seasonal changes, potassium deficiency, Greece

https://doi.org/10.17660/ActaHortic.1997.444.38