Table Of ContentSTUDIES IN THE AGRICULTURAL AND FOOD SCIENCES
Consultant Editors:
D. J. A. Cole University of Nottingham
W. Haresign University of Nottingham
W. Henrichsmeyer Director, Institut fiir Agrarpolitik, University of
Bonn
J.P. Hudson formerly Director, Long Ashton Research Station,
University of Bristol
G. Kimber Professor of Agronomy, University of
Missouri-Columbia
J.L. Krider Professor of Animal Sciences, Purdue University
G.E. Russell Professor of Agricultural Biology, University of
Newcastle-upon-Tyne
D. E. Tribe Professor of Animal Nutrition, University of
Melbourne
V.R. Young Professor of Nutritional Biochemistry,
Massachusetts Institute of Technology
STUDIES IN THE AGRICULTURAL
AND FOOD SCIENCES
Mineral Nutrition
of Fruit Trees
D. ATKINSON, BSc, PhD, MIBiol
J.E. JACKSON, BSc, PhD, FIBiol
R.O. SHARPLES, BSc, PhD
East Mailing Research Station
W.M.WALLER, BSc
Agricultural Development and Advisory Service
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First published 1980
© The several contributors named in the list of contents 1980
ISBN 0 408 10662 X
British Library Cataloguing in Publication Data
Symposium on Mineral Nutrition and Fruit Quality
of Temperate Zone Fruit Trees, Canterbury, 1979
Mineral nutrition of fruit trees. - (Studies in
the agricultural and food sciences).
1. Fruit trees - Congresses
2. Plants - Assimilation - Congresses
I. Title II. Atkinson, D III. International
Society for Horticultural Science IV. Series
634 SB356 79^41647
ISBN 0-408-10662-X
Phototypeset in 10/11 pt Times Roman by
Scribe Design, Gillingham, Kent.
Printed and bound in Great Britain by
Redwood Burn Ltd, Trowbridge & Esher
PREFACE
Just over ten years ago, increasing wastage in stored apples due to bitter pit,
a disorder caused by unbalanced tree nutrition, led to the convention of a
two-day discussion meeting in April 1969 at Haren-Groningen in Holland. It
was attended by West European workers concerned with the effects of
orchard nutrition and management on fruit quality and provided an oppor-
tunity for them to share their knowledge of the causes and methods of
control of this serious problem in commercial fruit production. The
meeting, which was held under the auspices of the International Society for
Horticultural Science (ISHS), was so successful that the participants
agreed to assemble again in 1974 at Bonn in the Federal Republic of
Germany. The second discussion meeting (Technical Communication of
ISHS, 1974; 445; 75 pp.) was extended to include papers and discussions on
the fundamental role of mineral nutrients in fruit physiology and the influ-
ence of storage conditions on the incidence of bitter pit. It was also agreed
that a further meeting in the series should be held in England in 1979.
Attendance at the 1969 and 1974 discussion meetings had attracted the
interest of workers concerned with the nutrition and the storage of fruit
crops in countries other than Western Europe and attendance at the third
meeting was therefore extended to participants who would contribute infor-
mation from a much wider range of fruit growing areas. Moreover, as other
aspects of fruit quality are also influenced by nutrition, the scope and the
length of the meeting was expanded to cover other forms of wastage or loss
of quality which occur during the growing and storage of temperate fruits.
In parallel with these developments there was demand for a meeting on
the mineral nutrition of fruit trees. Although there are regular meetings to
discuss plant mineral nutrition, most of these are general and deal with a
range of crops rather than allowing for discussion in depth of the require-
ments of any one type of crop. This meeting was organized to gather
together current knowledge on temperate fruit trees.
At the time of the meeting the balance of research on fruit tree nutrition
was changing from investigations of responses to fertilizers and other sup-
plementary nutrient applications to studies of other factors influencing
nutrition, i.e. soil management, orchard design, and to more fundamental
studies of the uptake, transport and remobilization of mineral nutrients and
their roles in tree growth and production. An opportunity to review what
had been done and to look forward was therefore timely. For many years
tissue (particularly leaf) analysis has been used in both research and advisory
work as a means of indicating the tree's nutritional status. However, there
v
vi Preface
are differences in methodology, in interpretation and in the concentrations
of nutrients regarded as optimal, between different laboratories and
countries and the meeting provided an opportunity for these to be discussed
in detail. Fortunately, it was possible to combine the above interests with
those on bitter pit and convene a conference where tree nutrition could be
integrated with nutritional effects on fruit quality.
As well as the formal presentation of invited full-length papers, short
communications were invited either for presentation in informal colloquia
or in 'poster' sessions. These are mainly presented as abstracts in the
Proceedings, but several have been expanded by their authors to full papers.
Much emphasis was on the discussions and many of the points that attracted
comment are recorded in the reports of the discussion sessions. The con-
ference programme was arranged with regard to organization requirements
as well as the relationship between the different areas of interest. Since no
such constraints apply to the Proceedings, the subject matter has been
rearranged in this volume to obtain a logical sequence which, after an
introduction to the subject by the Chairman of the ISHS Fruit Section,
begins with a section dealing with the effects of nutrition on fruit quality.
This is clearly the major objective of managing the nutrient supply to a crop
and provides a sense of purpose and scope to the succeeding sections. The
second section (Parts II, III and IV) deals with the mechanisms of nutrient
entry to, and movement within, fruit trees and the means of influencing the
nutrition of both the whole tree and the crop by fertilizers and by manage-
ment practices, including irrigation and the use of herbicides. The third
section (Part V) deals with methods for predicting the needs of the tree for
establishment, growth and fruit quality. The volume concludes with an
edited version of the final discussions where there was an attempt to syn-
thesize the preceding sessions and look forward.
The papers presented contain the views of the authors and there has been
no attempt to standardize these or to reconcile any differences; where these
do exist there is clearly a need for better understanding. It is believed that
these Proceedings form a basis for a more relevant approach to modern fruit
nutrition and that they summarize the current state of our knowledge of this
important subject.
D. Atkinson
R.O. Sharpies
ACKNOWLEDGEMENTS
It is a pleasure to acknowledge the help of all of the participants at the ISHS
Conference on Mineral Nutrition and Fruit Quality of Temperate Zone
Fruit Trees, whose efforts and contributions ensured the success of the
meeting.
Thanks are also due to Professor A.F. Posnette who opened the Con-
ference, to Professor J.F. Sutcliffe, Dr M. Faust, Dr K.J. Treharne, Pro-
fessor W.D. Naumann, Dr D.W.P. Greenham, Dr J. Terblanche, Dr D.W.
Robinson, Dr R.C. Little and Professor G. Biinemann who chaired the
sessions and to Miss Sandra A. Wilson, G.C. White, D.S. Johnson, Dr M.
Allen, Dr M. Knee, Dr C.A. Priestley, Dr S.M. Smith, M. Marks, Dr R.
Harrison-Murray, A. Chalmers and Dr K.J. Treharne who acted as rappor-
teurs at the scientific sessions.
We would also like to thank the trustees of the Agricultural Research
Council's Underwood Fund and the British Council for funds which allowed
some overseas participants to attend the meeting.
Christ Church College, Canterbury, provided an ideal setting for the
meeting and we are grateful to all the staff there who helped make the
meeting both constructive and enjoyable.
Mr B. F. Self provided advice and help with the Conference visits as well as
the local arrangements at Canterbury. Miss J. Mary Schroeder undertook
much of the detailed organizational work for the meetings and her efforts
were largely responsible for the smooth running of the Conference itself.
Assistance with typing and printing was provided by Mrs A. Morrisey, Mrs
K.D. Millgate, Mrs S. Gair and Mr D.G. Richardson.
The editors of this volume are particularly grateful to their colleagues at
East Mailing Research Station and the Agricultural Development and Advi-
sory Service at Wye for their assistance in the preparation of the Conference
papers from which this book has been prepared.
D.A.,J.E.J.,R.O.S.,W.M.W.
April 1980
vn
1
MINERAL NUTRITION AND FRUIT QUALITY OF TEMPERATE
ZONE FRUIT TREES
G. Bunemann
Institutfiir Obstbau und Bawnschule, der Technischen
Universitat, Hannover, F.R. Germany
The subject of this opening session might cover the knowledge accumulated
by research workers for at least 50 years. Of course, some basic knowledge
dates back even into the days of Justus von Liebig who became professor of
chemistry in GieBen, Germany, at the age of 21. In 1840 he published a book
on mineral nutrition of plants and is considered the father of mineral
fertilizer application in agriculture. Mineral fertilizers are often called 'arti-
ficial fertilizers', particularly by those who frown upon cultivation systems
which they do not consider 'natural' or 'biological'. Even in the modern
German Brockhaus Encyclopaedia a comment is made that Liebig might
have exaggerated the importance of mineral fertilizers. But in the same
paragraph credit is given to Liebig for the tremendous increase in agri-
cultural production and productivity during the last 100 years.
Although the meeting is concerned in more general terms with 'mineral
nutrition and fruit quality of temperate zone fruit trees', it is tempting to
devote too much time to disorders as affected by nutritional problems. In
this case it is often an excess of nutrition, one element or the other, that has
to take the blame for any quality defects. This paper does not resist that
temptation and will try to hitch up the present meeting with the very useful
discussions held previously at Haren (NL) and Bonn (Germany).
If we browse through older books on fruit production, we might find
comments such as (Bottner, J. 1920): 'Farmyard manure contains all nut-
rients in a relatively favourable proportion for plant roots. Artificial ferti-
lizers normally contain only one nutrient. The most important ones are
potash, phosphoric acid and nitrogen'. These words sound pretty familiar to
modern agronomists and horticulturists, and they will probably be heard in
the next millenium. In the same book we find a comment on liquid manure:
'If we apply liquid manure to a tree on a good and well-maintained soil which
can produce fine fruits on its own, we get an excess; the fruits get afflicted by
breakdown, bitter pit, and rot. This is not the fault of liquid manure per se\ it
should not be blamed, but the wrong treatment which aimed at something
entirely out of reach.' The author had obviously drawn on knowledge from
his own experience and from some of the literature available before the First
World War. And it is indeed surprising, how much had been written about
just one of the apple disorders, bitter pit, which to a large extent is due to
3
4 Mineral nutrition and fruit quality
some nutritional or metabolic failure. Our forefathers had notions on many
things in their bones which we have proved by intensive laboratory studies.
But our forefathers also arrived at erroneous interpretations which then had
to be proved wrong with great efforts by less superstitious research workers.
In 1912 a paper read like this (Bothe,1912): The year 1911 was hot and dry.
Although lime was abundant in an orchard near Bonn, bitter pit occurred in
almost 50 per cent of Winter Calville apples. Bitter pit and water core are
caused by excessive heat.'
In America, Brooks and Fisher (1916) wrote an article the title of which,
at least, is as true now as then: 'Spot diseases of apple causing much general
confusion.'
Brooks (1916) gave some figures on experience with water dosages in
August and September which, he found, promoted bitter pit on Grimes
Golden:
Water heavy throughout the season 43% pitted fruits
Water medium throughout the season 17% pitted fruits
Water medium until August, then heavy 49% pitted fruits
Water light throughout the season 14% pitted fruits
He did not speculate on what the abundant or less abundant presence of
water at various times during the growing season effected. In a later paper
Brooks and Fisher (1918) observed that the disease varied particularly with
the water holding capacity of the subsoil.
It could be fun to continue reading through quotations from old papers
from an annotated bibliography on bitter pit of apples (Bunemann, 1972).
Any number of reasons can be found there for the origin of bitter pit:
'nitrogen has nothing to do with it' (Sertiirner, 1921)
'a sample of pitted fruits seemed to be particularly high in ash, potassium
and magnesium content, phosphorus was low. Nitrogen from the sus-
ceptible location was high in both years, one with and one without
pitted fruits' (Brown, 1926)
'size and picking time are the main factors' (Wickens and Carne, 1927)
One of the oldest qualified statements from actual experimental evidence on
the subject of our symposium dates back to Brown (1929) who wrote:
'. . . good keeping qualities are associated with high percentages of potash
in the apple.'
The venerated master of Fruit Science in Denmark, Nils Esbjerg, wrote in
1935:
'Full organic manure resulted in largest percentage of bitter pit, followed
by "complete" mineral fertilizer.'
With this comment we might be back in balance concerning the opinions of
our ancestors, and the second part of this lecture should be devoted to a
review of more recent research in fruit quality problems related to mineral
nutrition.
It has become clear from what has been said previously that it is not
necessarily mineral nutrition per se, as opposed to organic nutrition, which
induces any specific quality. Therefore, active control or regulation of fruit
G. Biinemann 5
quality by any quantitative nutrient programme does not appear particularly
promising. It is to the merit, however, of research workers in such distant
parts of the world as North America, Japan, and Europe to have tried a
qualitative approach with particular emphasis on the seasonal influences of
water and nutrients. One of the first authors to have experimented syste-
matically in this direction was Aldrich (1931), but he worked entirely in the
field and was therefore more or less dependent on natural conditions which
varied from one year to the other. Mori and Yamazaki (1958) and their
group at Aomori Experiment Station in Japan worked in a more abstract
way, trying to assess the effect of presence or lack of nitrogen in an experi-
ment with apple trees in sand culture. They found that many of the effects
obtained were related to fruit size; later on potassium effects were also
observed. Askew (1935) came out of the boron corner and expanded his
work to all other elements. He and his coworkers reported (Askew, Watson
and Chittenden, 1957/58) that concentrations in fruit of nitrogen, phos-
phorus, magnesium and sodium increased from the first month after bloom
until harvest, whereas calcium did not. This was one of the pointers to the
problem of calcium supply to fruit tissues which was worked on so inten-
sively during the sixties and to the present. The mentioning of so many other
groups and individuals who further worked on these problems does not seem
necessary, because much of their work was documented in the last two
symposia held by the ISHS in which many of the members of the present
symposium have participated. The fact that the first two symposia were
essentially limited to bitter pit and problems apparently related to bitter pit
can probably be explained by the urgent necessity to tackle this particular
problem. The losses from bitter pit, breakdown, and other disorders cannot
very easily be expressed in percentage of crops or in monetary loss to
growers and dealers, but the importance still exists and has produced the
necessity for the present symposium. The fact that the apparent scope of the
conference was widened, was probably due to the interrelation between the
problems. All the so-called physiological disorders which are quite often
biochemical disorders, it seems, have something to do with how the fruit has
developed, and this seems to be a guiding thought throughout the pro-
gramme of the present meeting. The uptake of nutrients and the manage-
ment of nutrition — which is much more than just fertilizer application —
have been placed right at the beginning of the programme to lay the grounds
for discussions to follow under the heading 'Influence of nutrition on storage
quality of fruits'. Several posters are to be presented, and the attention of
the audience to this form of presentation is particularly requested. We all
have very little experience in this field, and yet it seems to be a very efficient
way of information transfer.
Publications in most recent times tend to consider soil and soil treatment
factors (e.g. Van der Boon 1977a, b and Van der Boon and Das, 1977 or
Stoll, Hauser and Datwyler, 1977), direct interrelation between supply of
nutrient elements to the roots (e.g. Lewis et al., 1977), as well as plant and
cultivation factors which were investigated in a great many experimental
stations and laboratories. Only a few papers from recent years will be
reviewed here, and some of the consequences their results may have had for
practical orchard management will be elucidated. Of course, some of the
management practices differ between regions due to soils and climates, but
6 Mineral nutrition and fruit quality
some more or less general trends of research and advice to growers can be
summarized without too much risk of going entirely astray.
At the Warsaw congress in 1974 Van Goor gave a review on distribution of
mineral nutrients in the plant in relation to physiological disorders. Defi-
ciencies of certain elements in certain plant parts may occur fairly indepen-
dent of availability in the soil. They are often an expression of unfavourable
ratios of nutrients in the soil, affecting the uptake and, after uptake, the
distribution and possibly the mutual interactions within the plant. The most
well-known example, of course, is calcium, but manganese and boron
should also be mentioned in this context. One of the orchard factors
obviously is an excess of potash in the soil or in parts of the soil stratum
exploited by the roots of our trees. Between the 'black strip' of orchard
surface, cleared by permanent application of herbicides, and the grass alleys
there may be considerable differences in pH, phosphorus, and potash
contents. The high potash and low pH in the 'black strip1 under the trees is
undesirable, but methods to alleviate this problem leave much to be desired
according to a paper by Van der Boon (1977a). He applied calcium and
magnesium as sulphates and succeeded in decreasing the soil potassium
figures slightly, but mulching caused a small increase again. The differences
in terms of fruit quality, especially keeping quality, were minute in this three
year observation, and a clear effect of mulching could not be observed
except for individual seasons. Several papers from the same station dealt
with calcium application to the ground, but the validity of these experiments
for other soil types may be considered doubtful. Yet, it may be worth
mentioning that the authors (Van der Boon and Das, 1977) themselves
conclude that calcium sprays during the growing season are still necessary,
because the soil treatment effects were too small. The annual differences
between disorder percentages even with varying (Ca + Mg)/K- ratios are
emphasized by Van der Boon (1977b). On the other hand, in one instance
early leaf drop occurred, probably as a symptom of incipient Mg deficiency
produced by the application of gypsum. This may serve as a warning that too
much activity of the grower trying to cure one problem efficiently may throw
him into another one . . .
Stoll et al. (1977) explained numerous fruit disorders by calcium
deficiency. Light crop is often associated with premature softening, and
particularly on the shaded side of the fruit higher potassium values are
observed, whereas calcium in these parts is particularly low. This then
results in a very high (K + Mg)/Ca ratio. According to Niederhauser (1977)
this is related to low calcium in the soil, but even more so to high potassium.
If the organic matter and clay contents of a soil are high, buffering alleviates
the problem, at least to a certain extent.
Schumacher, Fankhauser and Stadler (1978) brought in another aspect;
they investigated the susceptibility to pit depending on the location of the
fruit in the tree and analysed the fruits for their potassium, calcium and
magnesium contents. They also distinguished between fruits from laterals
on two-, three-, four-f year-old wood in the basal, medium, apical region of
the tree. For 'age of fruiting wood' they found a significant F value. Fruit size
is an important factor in any comparison between individual trees. In case of
comparable fruit size on two trees the fruits from the more vigorously
growing tree have more pitted fruits, and a K/Ca ratio over 36 was likely to
be associated with pit in 'Maigold', a highly susceptible Swiss variety. It was
