DEFICIENCY OF FE, MN, ZN IN COMMERCIAL ORCHARDS OF CRATAE GUS PUBESCENS (H.B.K.) STEND. – SUMMARY OF OBSERVATIONS.

Commercial plantations are established in soils ranging from very deep (3–5 m), permeable soils to very shallow (30–50 cm) on impermeable, calcareous rock, with pH range 4.5 – 8.3. Domesticated forms are grafted onto local seedlings of various Crataegus species.
Both the stock’s side shoots as well as scions showed abnormal color and shape of leaves.
Although the stock shoots showed strong Fe-chlorosis the scion part was often free of symptoms.
The same was found in the case of Zn symptoms.
In the last case, the Zn level in leaves of the scion was dropping from 44 (flowering) to 7 ppm (June) without any deficiencies in the shoot.
Thus, the Fe and Mn metabolism of the scion seems to be independent of the Fe and Zn metabolism of rootstock.
The reasons of low Zn level and shoot free symptoms are unknown.
Trees with typical marginal chlorosis, advancing between lateral veins, leaf downward curling, strongly expressed since August, were related with low Mn level (14 ppm – June sampling). Field observations show that low Mn and Zn in the second part of season do not influence hawthorn productivity.

International Symposium on Diagnosis of Nutritional Status of Deciduous Fruit Orchards

M.W. Borys

https://doi.org/10.17660/ActaHortic.1990.274.6