الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
The present investigation was conducted during
three successive seasons 1985, 1986 and 1987 to study
the nutritional status, vegetative growth, yield
and fruit quality of Washington navel orange, Valencia
orange and Balady mandarin trees in relation to orchard
location at three different regions within the Kaliobia
Governorate. Based on the results obtained during
the first two seasons, a correction treatment, using
potassium dihydrogen phosphate foliar sprays was
applied (in the third season) to the citrus cultivars
at the different locations under stud" ~ "and the response
of the trees to the correction treatment was evaluated.
Furthermore, the data sets obtained from these.experiments
and locations for washington navel orange under
study were used to develop a preliminary foliar nutrients
norms by calcUlating the interrelationships
between the levels of foliar nutrients and yield" ~ "
This set of interrelationships led to the selection
of reference values used to calculate the Diagrtosis
and Recommendation Integrated System (DRIS) indices,;-
This research introduces this new system to the
Egyptian Agriculture. DRIS uses nutrient concentration
ratios, rather than••the concentrations theaseleves,
to interpret tissue analysis. Therefore, it is based
on nutritional balance and indicates not only the
nutrient most likely to be limiting, but also the
order in which other nutrients are likely to become
limiting. Proper developoment and interpretation
of ORIS indices is crucial as they reflect relative
nutrient insufficiencies or excesses.
Three orchards were selected, each located
at a different region namely Moshtohor, Kafr Hassan
and Meet-Kinanah. Every orchard involved the three
citrus cultivars used in this st.udy., All trees were
growing on the sour orange rootstock. Trees of both
orange· cultivars were about 20-year-old and planted
5 meters apart, while mandarin trees were l5-year" ~ "old
and planted 3.5 meters apart. The three orchards
received approximately the same cultural care. In
each experimental orchard, ten healthy trees of every
cv., uniform as possible in vigour, were selected
carefully as being representatives of both the cultivar
and the locality. The soil of each orchard was mechanically
and chemically analysed at the three depths
i.e. ”0-30, 30-60 and 60-90 cm from the soil surface”.
The whole set of tree population was used in
the l" ~ " experiment, during 1985 and 1986 seasons,
to study the nutritional status of the trees in relation
to vegetative growth, yield and fruit quality
A.I.b. Leaf R , as influenced by KB2P04 foliar sprays:
The three citrus cultivars showed generally
a positive response in their leaf N level. However,
the response of Balady mandarin was more pronounced
at all orchard locations, while both Washington navel
orange and Valencia orange cultivars showed an increase
in leaf N level only at Kafr-Hassan and Meet-Kinanah
orchards, respectively. Generally, foliar
sprays had a limited effect on leaf N level at
Moshtohor, regardless of the citrus cv. It is not
easy to explain such results, but it may reflect
the differences in the specific behaviour af each
cultivar under certain set of conditions
A.2. Phosphorus:
A.2.a- Leaf P , in relation to orchard location:
The leaf P level in all citrus cvs at the three
orchard locations tended to be lower than the optimum
range. Such trend was more pronounced for the two
orange eva. at Moshtohor. While leaf P level was
generally, near the opti" ~ "um at Meet-Kinanah. This
could be attributed to the relatively higher soil
content of available P in the Meet-Kinanah orchard
as revealed from soil analysis.
(183)
A ..2;b- Leaf P •.as influenced by KB2PO” foliar sprays:
KH2P04 foliar sprays increased leaf P % in
all citrus cvs , Such increment was more pronounced
with Balady mandarin. On the other hand, trees at
Meet-Kinanah showed the least response in this respect.
A" ~ "3" ~ " Potassium:
A;3;a" ~ " Leaf K •.in relation to orchard location:
The K level in all citrus cvs , at the three
orchard locations was Low , However, leaf K content
of trees at Meet-Kinanah orchard was higher than
that of Kafr Hassan, while, trees of Moshtohor orchard
were the lowest in this respect.. Thes-e--result’sare
positively correlated with soil potassium content
of those orchards.
A.;3.;.b-· Leaf K •.as influenced by KB2PO” foliar sprays:
Leaf K level of sprayed trees was significantly
increased over those of the unsprayed ones in all
orchard regions except with Washington navel " ~ "orange
at Meet-Kinanah, where differences were not significant
at 1% level. Trees of Meet Kinanah orchard were
originally in a better leaf K status than the trees
at the other two locations.
A" ~ "4. calcitm:
The three citrus cvs. at Kafr Hassan orchard
showed higher leaf Ca level than those of Moshtohor
or Meet-Kinanah. Trees sprayed with KH2P04 showed
a slight decrease in leaf Ca % below the control
trees.
Magnesium:
Significant differences in leaf Mg % for all
citrus cultivars were recorded in relation to different
orchard locations. Trees in Moshtohor orchard had
the highest leaf Mg level, but those in Meet-’Kinanah
had the lowest level while trees in Kafr Hassan had
values inbetween, in this respect. KH2P04 foliar
sprays did not affect appreciably the leaf mg content
in any of the different citrus cvs. under study,
except Washington navel orange either in Moshtohor
or Kafr Hassan where leaf Mg level was significantly
decreased in sprayed trees.
Sodiuu
Generally, leaf Na content of--citrus evs in
Moshtohor orchard was at a higher level over those
of trees in the other two regions. Such higher level
was more pronounced in both Navel orange and Balady
(186),
level, while Balady mandarin had the highest Mn level
in the same orchard.. This condition may be related
to the amount of growth achieved by trees of different
cvs. at different locations and subsequently its
diluting effect on the Mn leaf content.
Leaf Mn % was not influenced by. KH2P04 sprays
in most cases except with Valencia orange in Moshtohor
and Balady mandarin at Kafr Hassan, where the Mn
level was positively affected.
A.9- Zinc:
All trees under study in the three different
locations showed that leaf Zn content was lower than
the optimum range. However, trees in the Moshtohor
orchard had generally the highest leaf Zn % followed
by those at Kafr-Hassan and Meet-Kinanah regions
in a descending order, for all citrus evs. under
study.KH2P04in leaf Zn %
foliar sprays resulted
for both orange cvs ,
in an increase
but no response
was recorded for Balady mandarin trees.
B,; " ~ "ee growth:
B" ~ "l. " ~ "ee canopy circtmference:
Orange trees at Kafr Hassan orchard had the
largest canopies while Balady mandarin trees at
Moshtohor were larger than those at Kafr-Bassan.
On the other hand, smallest canopies were
developed on trees of Valencia orange and Balady
mandarin at the Meet-Rinanah orchard.
KH2P04 foliar sprays increased tree canopy
circumference over the unsprayed ones. However, such .
increase was more pronounced at Moshtohor orchard
for both orange cvs. while at Meet-Rinanah the response
was appreciable only for Balady mandarin.
B.2.; Tree height:
Washington navel orange produced the tallest
trees at Meet-Rinanah,while Valencia orange and Balady
mandarin trees were taller at Kafr-Hassan than the
corresponding ones at the other two regions.
Generaliy, tree height was not appreciably
influenced by KH2P04 foliar sprays for all citrus
cvs , except Valencia orange at, Meet-Kinanah orchard
where sprayed trees were significantly taller than
the control •.
B" ~ "3" ~ " 2runk circuaference:
All citrus cvs. at Kafr Hassan produced the
largest trunk circumference while Washington navel
orange, at Moshtohor, had the smallest trunk circumference..
But valencia orange and Balady mandarin
were both smaller at Meet-Kinanah orchard ..
KH2P04 foliar sprays induced a slight increase
in trunk circumference· that was not significant in
most cases,;
B" ~ "”,,; Leaf dry weight: .
All citrus cvs. showed large variability in
leaf dry weight not only from one orchard location
to another but " ~ "lso from one growing season to another;
Generally, KH2P04 foliar sprays caused a slight
increase in leaf dry weight of different cvs. at
different locations that was not significant in most
cases.
Generally, it could be concluded that, although
vegetative growth parameters differed according to
both citrus cultivar and orchard location, but a
trend was detected for most cases. The highest values
for tree canopy circumference, tree height and trunk
circumference were observed at Kafr-Bassan orchard,
except that, tree height of Navel orange and canopy
circumference of Balady mandarin were higher’ at
Meet-Kinanah and Moshtohor orchards, respectively;
Moreover, the KH2P04 foliar sprays generally increased
growth measurements, but the increase in tree canopy
was more pronounced especially at Moshtohor and
Meet-Kinanah orchards for both orange cuItivars and
the Balady- mandarin, respectively" ~ " These results
may be correlated to the leaf mineral status of these
citrus cvs, in relation to orchard location; where
Moshtohor orchard showed generally the lowest level
of many nutrient elements, especially the critical
level of P and K. Furthermore, orange trees at
Moshtohor responded well to theKH2P04 correction
treatment..
Co; Yield and Biennial Bearing Indez:
C.;l" ~ " Yield:
Washington navel orange trees at Meet-Kinanah
orchard produced the highest yield during the three
seasons of study.. However, the same orchard yielded
the least crop of both valencia orange and Balady
-,» mandarin, when the latter trees were in the on-year
status. Valencia orange trees produced the highest
yield at Moshtohor allover the period of study..
The alternate bearing habit was clear in’ .B.a.l.ady
mandarin trees at all locations.. But tree yield
showed two opposite trends for Balady mandarin in
relation to orchard location; ·where in seasons of
the on-year status, both Moshtohor and Kafr -Hassan
gave high but comparable yields. The reverse was
true in the off-year season, where the yield of
Meet-Kinanah was the highest.
the Balady mandarin, respectively" ~ " These results
may be correlated to the leaf mineral status of these
citrus cve, in relation to orchard location; where
Moshtohor orchard
of many nutrient
level of P and
showed generally the lowest level
elements, especially the critical
K. Furthermore, orange trees at
Moshtohor responded well to the KH2P04 correction
treatment.
C; Yield and Biennial Bearinq Index:
C .l.,.; Yield:
Washington navel orange trees at Meet-Kinanah
orchard produced the highest yield during the three
seasons of study. However, the same orchard yielded
the least crop of both valencia oranqe and Balady
mandarin, when the latter trees were in the on-year
status. Valencia orange trees produced the highest
yield at Moshtohor allover the period of study.
The alternate bearing habit was clear in’ ’salady
mandarin trees at all locations. But tree yield
showed two opposite trends for Balady mandarin in
relation to orchard location; where in seasons of
the on-year status,· both Moshtohor and Kafr -Hassan
gave high but comparable yields. The reverse was
true in the off-year season, where the yield of
Meet-Xinanab was the highest.
the yield increase in these non-parthenocapic citrus
cultivars. In fact, magnesium level may be considered
as one of the reasonable factors due to its necessity
for seed development.
C.2. Biennial bearing indez:
Biennial bearing was quite obvious in the Balady
mandarin than in both Washington navel and Valencia
orange trees. However, all citrus cultivars showed
the highest tendency toward alternate bearing at
the Moshtohor location and the least alternate bearing
at Meet-Kinanah. Kafr-Hassan orchard was in between
in this respect.
D. Fruitquality:
D.I. Fruitphysical characters:
Generally r . both orange cuItivars tended to
produce the highest fruit weight at Meet-Kinanah
orchard with minor variability during the seasons" ~ "
However, the reverse was true for Balady mandarin
where fruits of Meet-Kinanah were the smallest.
XH2P04 foliar sprays resulted in a general
increase in fruit weight of all citrus cvs , under
study. But such increase lacked .significance in most
cases.
Fruit size and dimensions behaved, in most
cases, in a similar way as fruit weight" ~ "
Fruit shape index showed no apreciab1e difference
due to orchard location for both Washington navel
orange and Balady mandarin during all seasons of
study. However, Valencia orange fruits at Moshtohor
tended to be oblong, while fruits of the same cultivar,
at both Kafr-Hassan and Meet-Kinanah orchards, tended
to be round or slightly compressed.
KH2P04 foliar sprays did not affect appreciably
the fruit shape index of any of the three citrus
cva. at all orchards.
Regarding fruit peel thickness, fruits of both
orange cultivars had thinner rind at Moshtohor,
however, differences were more pronounced with
Washington navel orange •. On the other hand, Balady
mandarin fruit peel was thinner at Meet-Kinanah than
at.the other two locations.
KH2P04 foliar sprays increased peel thickness
for all citrus cvs., however, Valencia orange was
more responsive. Meanwhile, both orange cva. at
Moahtohor, positively responded to KB2PO4, sprays
while Balady mandarin took the opposite trend" ~ "
Considering fruit juice weight, no clear trend
could be noticed in relation to orchard location,
when each season was considered spearately. However,
taking the average of the three seasons, reveal a
similar trend to that .found for fruit weight 7 where
highest values were obtained from Meet-Kinanah regarding
the two orange cvs. and Moshtohor regarding
Balady mandarin.
KH2P04 foliar sprays slightly increased fruit
juice weight, such increases were not significant
in most cases.
D.2" ~ " Fruit cheadcal properties:
Fruit juice T.S.S.% varied from one season
to another. However, taking the average of the three
seasons, fruit juice T ..S..S.. showed the lowest values
for the two orange cultivars at Meet-Kinanah ozohard;
Meanwhile, Balady mandarin, gave comparable fruit
juice T ..S.S..at all locations..
Fruit juice T ..S..S,; % was decreased in response
to KB2P04 foliar sprays for all cultivars, especially
at both Kafr-Hassan and Meet-Kinanah ..
Trees at Moshtohor orchard produced fruits
having the lowest content of juice acidity, especially
Valencia orange and Balady mandarin during all seasons
of study. On the other hand, all cvs ..at Kafr-Hassan
produced fruits with the highest percentage of titratable
acidity;
.KH2P04 foliar sprays increased the fruit total
acidity of both Washington navel orange and Balady
mandarin at Meet-Kinanah: but was not effective at
the other two locations; An opposite trend was noted
for Valencia orange.
T.S.S./acid ratio showed highest values for
all cvs , under study at Moshtohor during the three
seasons. Moreover, differences, in this respect between
the other two locations were negligible, in most
cases.
Fruit juice T.S.S./acid ratio tended to increase
in response to KH2P04 foliar sprays, at both Moshtohor
and Kafr-Hassan orchards with all cvs , However, an
• .c opposite trend was noted at Meet-Kinanah •
.Ascorbic acid content was highest in fruit
juice of Meet-Kinanah orchard over those at the other
two locations, especially Balady mandarin.; This may
be related to the relatively higher leaf K , of trees
at Meet-Kinanah orchard;
significantly induced
higher ascorbic acid content in fruit juice over
those of unsprayed trees.
Generally, the noted differences in fruit physical
and chemical characteristics, in relation to
orchard environment or to KH2PO4 foliar sprays could
be a response to these factors acting in two different
ways; the first being a direct effect, and the second
is an indirect one resulting from ..the unparallelled
responses of trees in their vegetative growth and
fruiting behaviour, and consequently the interrelationships
involved in this respect.
B" ~ " PreliJI.inary application of the ORIS technique:
Mean and Coefficient of variation (cv) values
for the present data of nutrient concentration ratios
have.- been calculated and used for the calculation
of ORIS indices for nutrient a" ~ "alysis interpretation
of Washington navel orange. The indices so calculated
were compared to sufficiency range diagnoses, and
were tested for accuracy in predicting yield response
based on the data available in this work. In general,
where the sufficiency range method made a diagnosis,
it agreed with the ORIS diagnosis; ORIS indicated
not only the most-limiting nutrient, but also the’
order in which other nutrients would likely to become
limiting.
P. Concluding R..ar.ks:
1- A judicious fertilizer program should be based
on soil and leaf analysis of the concerned
orchard. Other factors of the local environment,
cI96}
in relation to the concerned cultivar, should
also be considered.
2- The Diagnosis and Recommendation Integrated
System (ORIS) developed .by Beaufils, should
be applied to serve as a foliar diagnostic
tool capable of revealing mineral imbalances
and predicting the fertilizer and other treatments
required by a given crop at a given site
to enhance the chances of obtaining a higher
yield. Therefore, this system may overcome
many limitations encounte" ~ "ed in applying the
critical or sufficiency’level appro" ~ "ch in diagnosing
mineral nutritional problems.
3- The application of potassium in the fertilization
program may prove to be beneficial in many
citrus orchards,;;
4- The method of application of phosphorus fertilizers
should be reevaluated to achieve better
availability and utilization of the a,.mounts
applied of that element.