Up Kiwifruit Nutrition diagnosis of nutritional disorders
GS Smith, CJ Asher and CJ Clark

Disorders producing symptoms mainly on the younger leaves

Deficiencies

15. Sulphur deficiency

Sulphur deficiency causes some visible symptoms which resemble those of nitrogen deficiency. These include a severe reduction in growth and the development of pale-green to yellow leaves. An important point of difference, however, is that the symptoms of sulphur deficiency are confined to the younger leaves, the older leaves remaining green and healthy (Photos 15a, 15b and 15c).

Initially a diffuse pale-green to yellow chlorosis develops near the margins of the younger leaves (Photo 15d). The chlorosis then spreads progressively over most of the leaf. A distinctive wedge shaped zone of green tissue is often retained at the junction of the major veins and the midrib (Photo 15e).

In the case of a severe deficiency of sulphur, the interveinal tissue of the youngest leaves becomes completely chlorotic and, unlike severe nitrogen deficiency, the veins also lose their green colour (Photo 15f). A further feature which distinguishes sulphur deficiency from nitrogen deficiency is that there is no marginal scorching of the affected leaves.

Sulphur concentrations in fully expanded leaves of healthy plants sampled in the field at mid season usually range from 0.25 to 0.45 per cent of the dry matter. Results from the solution culture studies and of analysis of leaf samples taken in the field indicate that symptoms of sulphur deficiency do not usually appear until the concentration in fully expanded leaves falls below 0.18 per cent dry matter.

Few cases of sulphur deficiency have been observed in kiwifruit grown in New Zealand. The widespread use of fertilisers which contain relatively large amounts of sulphur such as single superphosphate (12 per cent w/w S), ammonium sulphate (24 per cent w/w S), and magnesium sulphate (13 per cent w/w S) probably accounts for the low incidence of this disorder. Furthermore, only small quantities of sulphur are removed in fruit (Table 2). A guide to the soils which are likely to be low in sulphur can be obtained from the review of the sulphur status of New Zealand soils7,25.

Click any image to view an enlargement
15a 15b 15c
15d 15e 15f

Originally published 1985 ISBN 0-9597693-0-7, revised 1987, republished for HortNET 1997
Copyright © 1997 The Horticulture and Food Research Institute of New Zealand Ltd. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission is prohibited.