Study on response of rice varieties to different nitrogen fertilizer levels
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Date
2015
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Rice (Oryza sativa L.) is the single most important crop and the staple food of more than three
billion people or more than half of the world’s population. Paddy is cultivated as a wetland crop
in all districts. Direct or indirect involvement for paddy sector is more than 30 % of the total
labour force (Wickramasinhe and Wijewardena, 2000). Rice provides 45% total calorie and 40%
total protein requirement of an average Sri Lankan (Department of Agriculture,2010).The
areaunder paddy production in yalaand maha was 1,671,054 Mt and 2,629,566 Mt respectively
(Department of Census and Statistics, 2010). Nitrogen, phosphorous and potassium are the three
major nutrients required for the rice plant. Nitrogen (N) is one of the essential macro -nutrients
for rice growth and one of the main factors to be considered for developing a high-yielding rice
cultivar. Nitrogen increases plant height, panicle number, leaf size, spikelet number, and number
of filled spikelets, which largely determine the yield capacity of a rice plant. Panicle number is
largely influenced by the number of tillers that develop during the vegetative stage. Rice plants
require nitrogen during the tillering stage to ensure a sufficient number of panicles and
reproductive to grain filling. Nitrogen imbalance in soil produces low fertilizer use efficiency,
low yields and low farmer profit.Main nitrogen loss mechanisms are volatilization of ammonia
(NH3), leaching loss of nitrate (NO3-), loss through denitrification and soil erosion (Choudhury
and Kennedy, 2005).Therefore, optimum level of nitrogen fertilizer should be applied to get
maximum yield of paddy cultivation and utilize nitrogen fertilizers effectively (Fageria and
Baligar, 2003).
Materials and Methods
This study was conducted at the Rice Research Development Institute (RRDI) at Batalagoda in
Kurunagala district, Sri Lanka. Fertilizers used were urea as the Nitrogen source, and others;
Triple super phosphate and Murate of Potash. The experiment was comprised with sixteen
treatments. Nitrogen fertilizer was applied as 0, 50, 100 and150 kg N ha-1. Four rice varieties,
Bg 1350 (V1), Bg 997 (V2), Bg 379-2 (V3) and Bg 450 (V4) were tested. These four rice
varieties are in age group of four to four and half months.Sixty four plots were arranged
according to the split plot design with sixteen treatments and four replicates.
Plant height, number of tillers per hill, plant greenness, number of days for 100 % flowering of
rice varieties, dry weight of shoot parts, plant nitrogen content, number of panicles per hill and
grain yield were measured against different nitrogen levels.
As the results showed (Table 1) there was a significant effect (P<0.005) among the treatments
for the plant height, number of tillers per hill, plant greenness, number of days for 100 %
flowering of rice varieties, plant nitrogen content, number of panicles per hill and grain yield.
There is no statistically significant difference among the levels of nitrogen and variety with dry
weight of shoot parts.
Description
Keywords
Agriculture, Export Agriculture, Crop Production, Chemical