Seasonal Variation in Nutrient Components of Mulberry Leaf and their Uptake in Response to Split Application of NPK under Temperate Conditions
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Date
2012
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SKUAST Kashmir
Abstract
Investigation on “Seasonal Variation in Nutrient Components of Mulberry
Leaf and their Uptake in Response to Split Application of NPK under Temperate
Conditions” was carried at the experimental farm of Temperate Sericulture
Research Institute, SKUAST-Kashmir, Mirgund which is located at 340.17′ N
latitude and 740.17′ E longitude at an altitude of 1585 meters above mean sea
level. The experiment was laid down in RBD during 2009 and 2010 with 11
different combinations of N: P: K and two controls, one where no fertiliser was
used and the other as available in package and practices for Sericulture. Fertilisers
were applied in two splits, first in the first week of April and the second split in
the last week of June after harvesting first crop. Nitrogen was applied in three
levels viz., N1, N2 and N3 (150 +150; 180 + 120 and 120 + 180), phosphorus in
two levels viz., P1 and P2 (120 + 00 and 60 + 60) and potassium was also applied
in two levels K1 and K2 (120 + 00 and 60 + 60) respectively. Soil analysis
conducted at initial stage, after first harvest and at the end of second harvest (April
1, June 1 and October 1) revealed that pH decreased with the advancement of
season, electrical conductivity showed slight increase on 2nd sampling date while
as organic carbon depicted decrease on 2nd sampling date. It further revealed that
NPK applied in first split (April) had either been utilised by the plants or got
leached or fixed. Foliar analysis conducted during 1st phase (prior to pruning on
May 1, May 15 and June 1) and 2nd phase (after pruning on August 1, August 15,
September 1, September 15 and October 1) on eight sampling dates revealed that
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nitrogen, phosphorus, potassium, sulphur, zinc and copper contents in leaf
decreased with advancement of age, while as calcium, magnesium, iron and
manganese accumulated in leaves with maturity. During 2nd phase the
concentration of N, P, K, S, Zn, Fe, Cu was comparatively lesser than that of first
phase on corresponding sampling dates, contrary was the case with Ca, Mg and
Mn which recorded higher concentrations during 2nd phase. Fertiliser levels did
exhibit their influence on the respective nutrient contents in the leaves and their
uptake. Higher content of nitrogen was recorded in treatments with higher levels
of soil application viz., N2 (3.696 %) in first phase and N3 (3.690 %) in second
phase. P2 level exhibited maximum phosphorus content (0.274 %) in 1st phase as
well as in 2nd phase (0.225 %). Highest potassium content (1.845 %) in leaves was
recorded with K1 in first phase and with K2 (1.460 %) in second phase. Split
application of NPK did also exhibit positive influence on rest of the foliar
contents and their uptake. Significantly higher leaf yield (14379.1 kg/ha) was
recorded in autumn as against spring (12553.4 kg/ha). Higher levels of nitrogen in
NPK combination did influence leaf yield (15196.5 kg/ha) in spring as well as in
autumn (16850.7 kg/ha). Nitrogen, potassium, calcium, magnesium, iron and
manganese recorded higher uptake (131.94, 63.54, 73.41, 25.37, 11.36, 3.81
kg/ha) during autumn season whereas phosphorus, sulphur, zinc and copper
recorded higher uptake (7.35, 6.81, 0.76 and 0.46 kg/ha) during spring season.
Fertiliser split/levels did exhibit influence not only on the uptake of constituting
nutrient elements but also on most of the other nutrients. Maximum leaf moisture
content (76.471 %) in spring and in autumn (75.531 %) was recorded on first
sampling dates of both phases and declined with advancement in the season
during both the phases. Leaf moisture retention capacity too exhibited decrease
with the advancement of season recording highest (91.084 and 87.42; 81.235 and
75.826 %) at 6 and 12 hours respectively on first sampling date of both the
phases. Positively significant correlation was found between nutrients in the soil
with that of leaf nutrients. Positive and significant correlation was recorded
between leaf yield and nitrogen at 0-30 cm depth (r = 0.603); phosphorus ( r =
0.619 ) for 0-30 and 30 -60 cm depth during spring while as during autumn it was
significant and positive with nitrogen (r = 0.564 and 0.601) for 0 - 30 and 30 - 60
cm depth respectively. Split application of P and K along with N exhibited
improvement in quality and quantity of mulberry leaf especially during second
phase suggesting the need for rescheduling the existing fertiliser schedule under
Kashmir climatic conditions for maximization of leaf harvest, both qualitatively
and quantitatively to enable farmers to undertake second silkworm rearing
commercially.
Description
PhD Thesis submitted to SKUAST Kashmir
Keywords
Sericulture, Mulberry, NPK, Split application