PERFORMANCE OF AEROBIC RICE (Oryza sativa L) UNDER DIFFERENT MICRO-CLIMATIC REGIMES
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Date
2018-07
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AAU, Jorhat
Abstract
A field experiment entitled “Performance of aerobic rice (Oryza sativa L.)
under different micro-climatic regimes” was carried out at Instructional-cum-
Research (ICR) farm, Assam Agricultural University, Jorhat during autumn season of
2017. The experiment was laid out in split-plot design with three replications. The
treatments of the experiment consisted of four micro-climatic regimes in main plot
viz., sowing of seed on 15th February (M1), 1st March (M2), 16th March (M3) and 1st
April (M4) along with four different rice varieties viz., CR-Dhan 205 (V1), CR-Dhan
203 (V2), CR-Dhan 204 (V3) and Inglongkiri (V4) in sub plot. The soil of the
experimental plot was sandy loam, acidic in reaction (pH 5.2), medium in organic
carbon content (0.62 %), medium in available N (311.5 kg/ha), low in available P2O5
(15.8 kg/ha) and medium in available K2O (194.0 kg /ha). The total rainfall received
during the experimental period was 1552.6 mm.
The results of the experiment revealed that the four different micro-climatic
regimes brought significant effect on morphological and physiological characters in
terms of plant population, dry matter accumulation, number of leaves/plant, leaf area
index, yield attributing characters, grain and straw yield and NPK-uptake of aerobic
rice. The micro-climatic regime associated with sowing of seed on April 1st recorded
higher values for all those characters. The highest grain (3004 kg/ha) and straw (4854
kg/ha) yields were obtained in April 1st sown crop which was at par with 16th March
sowing. The uptake of nitrogen, phosphorous and potassium in grain, straw and total
uptake were significantly higher in April 1st sown crop. The favorable micro-climatic
parameters viz., canopy temperature, light intensity, soil temperature and soil moisture
in all stages of crop growth were observed in micro-climatic regime associated with
1st April sown crop.
Different rice varieties could bring about significant differences in growth
parameters, yield attributing characters, grain and straw yield and NPK-uptake.
Among all the rice varieties, CR-Dhan 203 recorded the highest value in terms of
plant population, dry matter accumulation, number of leaves/plant, leaf area index,
yield attributing characters and ultimately in grain yield followed by Inglongkiri, CRDhan
204 and CR-Dhan 205. The highest grain yield of 2860 kg/ha recorded in rice
variety CR-Dhan 203 was significantly superior to that of other varieties except
Inglongkiri. The rice variety CR-Dhan 203 also recorded the highest NPK- uptake.
In terms of economics, the treatment combination of aerobic rice variety CRDhan
203 sown on 1st April resulted the highest benefit-cost ratio (2.66) and was
found to be the best treatment combination followed by the variety Inglongkiri sown
on 1st April (2.56).