Foliar nitrogen application under reduced sunlight intensity in rice (Oryza sativa L.)
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Date
2021
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Punjab Agricultural University, Ludhiana
Abstract
The study entitled, “Foliar nitrogen application under reduced sunlight intensity in rice (Oryza
sativa L.)” was conducted at Department of Climate Change and Agricultural Meteorology,
Punjab Agricultural University, Ludhiana and Krishi Vigyan Kendra, Bahowal, Hoshiarpur.
The soil of experimental field was loamy sand in texture at both the locations, medium in
organic carbon, available nitrogen, phosphorus and potassium at Ludhiana, high in organic
carbon and available nitrogen and medium in available phosphorous and potassium at
Hoshiarpur. The soil was normal in reaction at both the locations. The experiment was
conducted in randomized block design with three replications. The 20 treatment combinations
comprised of four levels of sunlight intensity (control, 50% reduction in sunlight light
intensity from 15-45, 46-75 and 76-105 DAT) and five levels of foliar nitrogen application
(control, spray of 3% urea before, midway, afterwards and midway-afterwards the reduction
in sunlight intensity). Sunlight intensity was reduced by covering the plots from top (leaving
the sides open) with green shade net capable of reducing 50% sunlight intensity. The shade
net was placed with the help of GI pipe structures specially prepared for this purpose. Rice
variety used in the experiment was PR 122. At harvest, the growth parameters like plant
height was significantly increased when sunlight intensity was reduced from 46-75 DAT as
compared to control and other parameters like number of tillers m-2 and dry matter
accumulation were significantly decreased at harvest when sunlight intensity was reduced
from 46-75 DAT as compared to control at both the locations. Maximum reduction in the
yield attributes like number of effective tillers m-2, panicle length and number of grains
panicle-1 was also observed when there was reduction in sunlight intensity from 46-75 DAT as
compared to full sunlight intensity at both the locations. Significantly lowest grain yield
(48.70 and 53.44 q ha-1 at Ludhiana and Hoshiarpur, respectively) as compared to other levels
of the treatment was recorded with the reduction in sunlight intensity during 46-75 DAT.
Reduction in sunlight intensity during any period caused a significant increase in chlorophyll
content and minimum cooking time of milled rice, while it significantly decreased the
elongation ratio of milled rice as compared to control. All other quality parameters were
observed to vary statistically non-significantly with the reduction in the sunlight intensity.
The application of foliar nitrogen before the reduction in the sunlight intensity recorded the
highest values of growth parameters, yield attributes, grain and biological yield, chlorophyll
content and the minimum cooking time of rice.
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Citation
Garima (2021). Foliar nitrogen application under reduced sunlight intensity in rice (Oryza sativa L.) (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.