Short communication

 Apricot (Prunus armeniaca L.) occupies an
important position in terms of area and production among
stone fruits. It is grown commercially in Kashmir valley and
‘New Castle’ is a popular variety. Foliar analysis is an
accepted tool to ascertain adequacy or otherwise of mineral
nutrient status in fruit plants. However, this needs to be
standardized for selection of index leaf for a given nutrient
element. The most suitable leaf position and sampling time
are those that show least variation in mineral concentration
(Mason, 1958). Nutrient standards developed for
recommendation of fertilizers are specified to a cultivar, and
under particular climatic conditions (Westwood, 1993). As
no such information is available on apricot grown in Kashmir
valley, the present study intended to bridge this gap.

The study was conducted on ‘Newcastle’ apricot in
our Experimental Orchard during 2009-10. Four healthy trees
of uniform age, size and vigour were chosen. Three leaf
sampling positions were selected, i.e., top, middle and basal.
Leaf samples with petioles were collected at 15 day
intervals, viz., 1st and 15th of each month, starting from May
to September. Leaf samples were thoroughly washed first
with tap water, then with 0.1NHCl and, distilled and double
distilled water. Washed samples were then dried in shade
and, subsequently, in an oven at 68oC, ground and, finally
stored for chemical analysis. Nitrogen content was
determined by Micro-Kjeldhals distillation method
(A.O.A.C., 1980), phosphorus by ammonium
molybdate:ammonium meta vanadate method, potassium and

Standardization of leaf sampling technique for macronutrients in apricot under
temperate conditions

H.U. Rehman, M.K. Sharma and F.A. Banday
Division of Fruit Science

Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir
Shalimar-191 121, India

E-mail : drsharma_mk@rediffmail.com

ABSTRACT

Macro- and micro-nutrient content influenced by position of leaf on the shoot and time of sampling was studied to
determine leaf-sampling time for apricot grown in temperate region of the country. Results revealed that middle order
leaves were the most suitable for determining nutrient needs in apricot trees. Leaf samples should be collected during
June - July for determining N, K and Ca; first fortnight of July for P; and, from mid-June to mid-July for Mg.

Key words: Leaf sampling, apricot, nutritional diagnosis, suitable sampling date

calcium by flame photometer, U.K. (Jackson, 1967) and
magnesium by Atomic Absorption Spectrophotometer.
Results were expressed as percentage on dry matter basis.
Data was analyzed by the method of Gomez and Gomez
(1983).

Variation in leaf N content in apricot followed a
definite trend during the sampling season (Fig. 1). N content
of basal and top leaves increased significantly from first
sampling date, i.e., May 1 and upto June 15. Thereafter, it
decreased significantly to the lowest value on September 1.
However, no period of stability in N content was recorded

Fig 1. Nitrogen content in apricot leaf influenced by
position of leaf on the shoot and time of sampling (%
dry weight)

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99

Leaf sampling in apricot

in basal and top leaves. Although N content of middle leaves
exhibited a similar trend as in basal and top leaves, during
June 1 to July 1, it remained statistically at par. Mean N
content of apricot leaves increased, irrespective of position
of the leaf on the shoot from May 1 to June 15 as a result of
both current absorption and remobilization of N accumulated
in the previous season. Mean N content was recorded
highest in ‘top’ positioned leaves, followed by middle and
basal leaves. Nitrogen, being a mobile element, tends to
accumulate in top leaves (Singh and Rajput, 1978). Similar
results were recorded by Verma and Bhandari (1990) and
Malik and Ahmad (2008).

Phosphorus content of top and basal leaves showed
a decreasing trend from first sampling date to the last
sampling date (Fig. 2). No period of ‘least variation’ was
observed in top and basal leaves. Similarly, P content in

middle leaves decreased significantly from May 1 to July 1,
followed by a nutrient stability period of July 1 to July
15.Subsequently, P content of the middle leaves again
declined significantly upto the last sampling date, i.e.
September 1. The decline in P content could be due to dilution
effects of growth, and it being a mobile element, significant
remobilization of this element may have occurred to various
sinks, prior to leaf-fall (Clark and Smith, 1990). Mean P
content showed significant difference among leaf positions
and was recorded highest in the top leaves, followed by
middle leaves, and was lowest in the basal leaves. The
present results agree with earlier reports of Batjer and
Westwood (1958).

Potassium content, irrespective of position of the leaf
on the shoot, followed a similar trend from May 1 to June 1,
and thereafter, K content of top and basal leaves decreased
significantly upto the last sampling date. However, K content
of middle leaves showed least variation i.e., highest stability
from June 1 to July 1. Thereafter,  it showed a trend similar
to that in top and basal leaves (Fig. 3). Highest level of K
was noticed in top leaves, followed by middle leaves and
was lowest in the basal leaves. These results are in
conformity with findings of Lekhova (1974) and Verma and
Bhandari (1990).

Calcium content, irrespective of leaf-position on the
shoot, showed an increasing trend from May 1 (the first
sampling date) to September 1 (the last sampling date).
Increase in Ca content was significant in top and basal leaves,
and no period of stability was observed in any pair of sampling
dates (Fig. 4). There was, however, gradual but non-
significant increase in Ca content between June 1 - July 1.
The ever-increasing concentration of Ca may be attributed
to limited mobility of calcium in the phloem and, also, low
demand in the fruit (Smith; 1962 and Shear and Faust, 1980).
Ca content of leaf samples increased with leaf position on
shoot basipetally, since, deposition of Ca as calcium pectate
in the middle lamella increases with age of the leaf. The
present findings are in agreement with observations of Verma
and Bhandari (1990) and Malik and Ahmad (2008) wherein
authors reported higher Ca content with advancing age of
the leaf.

Magnesium content of top leaves increased
significantly between May 1 - June 15. Between June 15 -
July 1, significant decrease in Mg content was observed
(Fig. 5). From July 1 to August 1, an increasing trend in Mg
content was noticed. Thereafter, Mg content showed
significant decline with advancement of sampling season.

Fig 2. Phosphorus content in apricot leaf influenced
by position of leaf on the shoot and time of sampling
(% dry weight)

Fig 3. Potassium content in apricot leaf influenced
by position of leaf on shoot the and time of sampling
(% dry weight)

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100

Although Mg content of middle leaves followed an exactly
similar trend as that in top leaves, change in Mg content
between June 15 - July 15 was non-significant in the case
of middle leaves. Change in Mg content of basal leaves on
all dates of sampling was statistically significant, and no
period of stability in Mg content of basal leaves was
observed. These findings may be attributed to the relatively
limited mobility of Mg in phloem, as also low demand in the
fruit (Smith, 1962; Shear and Faust, 1980). Decrease in
magnesium content during September may have been due
to lower soil temperature, which alters root activity and, in
turn, affects cation absorption (Melich and Reed, 1948).
Highest mean value of Mg content was recorded in the
basal leaves, followed by middle and top leaves.

Thus, it can be concluded that middle leaves of current

Fig 4. Calcium content in apricot leaf influenced
by position of leaf on the shoot and time of sampling
 (% dry weight)

Fig 5.  Magnesium content in apricot leaf
influenced by position of leaf on the shoot and time
of sampling (% dry weight)

season’s growth are the most suitable for determining nutrient
needs in the apricot tree. Leaf samples should be collected
starting from early June to early July for determining N, K
and Ca; during the first fortnight of July for determining P,
and from mid-June to mid-July for determining Mg.

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(MS Received 16 May 2011, Revised 19 May 2012)

Rehman et al

J. Hortl. Sci.
Vol. 7(1):98-100, 2012