ENHANCING THE PRODUCTIVITY AND QUALITY OF BLACKGRAM (Vigna mungo L.) WITH POTASSIUM FERTILIZATION IN ALFISOLS
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Date
2024-03-06
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Acharya N G Ranga Agricultural University
Abstract
A field experiment entitled “Enhancing the productivity and quality of
blackgram (Vigna radiata L.) with potassium fertilization in alfisols” was carried out
during rabi, 2021-22 on sandy loam soil of Wetland Farm of S.V. Agricultural College,
Tirupati campus of Acharya N.G. Ranga Agricultural University. The present experiment
was laid out in a randomized block design with factorial concept and replicated thrice.
The treatments comprised of three levels of potassium viz., 20 kg K2O ha-1, 30 kg K2O
ha-1 and 40 kg K2O ha-1 as first factor and five foliar sprays viz., no foliar spray, water
spray at flowering and pod development stages, 0.5 % KNO3 at flowering and pod
development stages, 1 % KCl at flowering and pod development stages and 1 % KH2PO4
at flowering and pod development stages as second factor. The soil of the experimental
field was sandy loam in texture, neutral in soil reaction, low in organic carbon and
available nitrogen, medium in available phosphorus and available potassium. The test
variety of blackgram used in the present investigation was TBG-104.
Results indicated that soil application of 40 kg K2O ha-1 (K3) resulted in taller
plants, maximum leaf area index, higher dry matter production and SPAD reading at all
the growth stages of blackgram, which was at par with 30 kg K2O ha-1 (K2) and both the
above treatments were significantly superior to 20 kg K2O ha-1 (K1), which recorded the
lowest growth parameters. Among the foliar sprays tested, application of 1 % KH2PO4 at
flowering and pod development stages (F5) recorded higher growth parameters, which
was however comparable with 0.5 % KNO3 at flowering and pod development stages (F3)
and 1 % KCl at flowering and pod development stages (F4). The deflated stature of growth
parameters was recorded with no foliar spray (F1), which was on par with water spray at
flowering and pod development stages (F2).
Soil application of 40 kg K2O ha-1 (K3) significantly improved the yield attributes
viz., number of filled pods plant-1 and number of seeds pod-1, which was on par with 30
kg K2O ha-1 (K2), while all the yield attributes were lower with soil application of 20 kg
K2O ha-1 (K1). Among the foliar sprays, application of 1 % KH2PO4 at flowering and pod
development stages (F5) recorded significantly higher stature of yield attributes, which
was on par with foliar application of 0.5 % KNO3 at flowering and pod development
stages (F3) and 1 % KCl at flowering and pod development stages (F4). All the yield
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attributes were at the lowest with no foliar spray (F1), which was comparable with water
spray at flowering and pod development stages (F2). However, test weight was not
significantly influenced by soil and foliar potassium fertilization.
The highest seed yield, haulm yield, harvest index and protein content of
blackgram was recorded with soil application of 40 kg K2O ha-1 (K3), which was on par
with 30 kg K2O ha-1 (K2). The lowest seed yield, haulm yield, harvest index and protein
content was recorded with soil application of 20 kg K2O ha-1 (K1). With regard to the
foliar sprays tested, application of 1 % KH2PO4 at flowering and pod development stages
(F5) recorded significantly higher seed yield, haulm yield, harvest index and protein
content, which was on par with foliar application of 0.5 % KNO3 at flowering and pod
development stages (F3) and 1 % KCl at flowering and pod development stages (F4).
Significantly lowest seed yield, haulm yield, harvest index and protein content were
recorded with no foliar spray (F1), which was comparable with water spray at flowering
and pod development stages (F2).
Nutrients i.e. NPK uptake by blackgram at harvest and post-harvest soil nutrient
status viz., available nitrogen, phosphorus and potassium was significantly enhanced with
soil application of 40 kg K2O ha-1 (K3), which was on par with 30 kg K2O ha-1 (K2). The
lowest nutrient uptake and post-harvest soil nutrient status was recorded with soil
application of 20 kg K2O ha-1 (K1). Among the foliar sprays tried, application of 1 %
KH2PO4 at flowering and pod development stages (F5), recorded higher NPK uptake
which was on par with foliar application of 0.5 % KNO3 at flowering and pod
development stages (F3) and 1 % KCl at flowering and pod development stages (F4).
Significantly lowest NPK uptake by blackgram at harvest was recorded with no foliar
spray (F1), which was comparable with water spray at flowering and pod development
stages (F2). The effect of foliar sprays on post-harvest soil nutrient status was found to be
non-significant.
The highest gross and net returns with higher benefit-cost ratio were realized with
soil application of 40 kg K2O ha-1 (K3), which was on par with 30 kg K2O ha-1 (K2). The
lowest gross returns, net returns and B:C ratio was recorded with soil application of 20
kg K2O ha-1 (K1). With regard to the foliar sprays tested, application of 1 % KH2PO4 at
flowering and pod development stages (F5) recorded significantly higher gross returns
and net returns, which was on par with foliar application of 0.5 % KNO3 at flowering and
pod development stages (F3) and 1 % KCl at flowering and pod development stages (F4),
whereas, higher B:C ratio was recorded with foliar application of 1 % KCl at flowering
and pod development stages (F4), followed by1 % KH2PO4 at flowering and pod
development stages (F5) and 0.5 % KNO3 at flowering and pod development stages (F3).
Significantly lowest gross returns, net returns and B:C ratio was recorded with no foliar
spray (F1), which was comparable with water spray at flowering and pod development
stages (F2).
From the present study, it can be concluded that RDF (20 : 50 kg N, P2O5 ha-1) +
soil application of 40 kg K2O ha-1 or 30 kg K2O ha-1 along with foliar spray of 1 % KCl
or 1 % KH2PO4 or 0.5 % KNO3 at flowering and pod development stages proved to be
promising in realizing higher seed yield, haulm yield, protein content and economic
returns in blackgram