ISSN:
1573-5036
Keywords:
Key words
;
anions
;
chloride
;
flowers
;
fruit yield
;
kiwifruit
;
potassium
;
sulphate
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The effects of K fertiliser (160 kg ha-1) applied with Cl- or SO4 2- as the accompanying anion on the K nutrition of kiwifruit (Actinidia deliciosa var. deliciosa) were assessed in a field experiment, using vines with varying degrees of K deficiency. Leaf K concentrations in spring were significantly higher for vines receiving KCl, compared to those receiving K2SO4. This effect did not interact significantly with the degree of K deficiency, and persisted for about 6 weeks. Subsequently there was no significant difference between the leaf K concentrations for the vines receiving KCl or K2SO4. Applying K as KCl increased the leaf Cl concentration, especially in spring, while applying K as K2SO4 had no significant effect on the leaf S concentration at that time. These results implied a greater requirement for organic acid anions for K+ uptake from K2SO4 than from KCl, and the importance of organic acid anions for K+ uptake from different sources of K fertiliser is discussed. This transient effect of the accompanying anion on leaf K status was associated with large effects on flowering, and fruit yields were about 28% higher for plants receiving KCl rather than K2SO4. The effects on growth and tissue nutrient composition of varying the concentrations of Cl-, NO3 -, SO4 2- and H2PO4 - around the roots of kiwifruit vines were examined in a solution culture experiment. For H2PO4 -, plant growth was very similar over a wide range of rates of addition. For the other anions, the range between deficiency and ‘toxicity’ was clearly delineated. For Cl- and NO3 -, toxicity was associated with high tissue concentrations of Cl and N, respectively, and was consistent with competition for uptake between Cl- and NO3 -. However, for SO4 2-, toxicity was associated with only a small increase in the tissue S concentration relative to that associated with maximum growth, and appeared to result more from effects on uptake of other anions and cations rather than from direct effects of high tissue S concentrations. It is concluded that the sensitivity of kiwifruit to the anion accompanying K+ in fertiliser may be related to the unusually high requirement for Cl previously reported for this species.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00009193
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