REAL TIME NITROGEN APPLICATION IN WINTER RICE UNDER DIFFERENT CROP ESTABLISHMENT TECHNIQUES
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Date
2020-10
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AAU, Jorhat
Abstract
A field experiment entitled “Real time nitrogen application in winter rice under
different crop establishment techniques” was carried out in the year 2017 and 2018 in
the Instructional-Cum-Research (ICR) farm, Assam Agricultural University, Jorhat to
study the relative performance of winter rice varieties with LCC- based N application
under different crop establishment techniques.
The experiment was comprising of 45 treatment combinations with three
varieties viz., V1: Ranjit, V2: Bahadur, V3: Gitesh; three crop establishment techniques
viz., M1: Transplanting, M2: System of Rice Intensification, M3: Direct seeding by drum
seeder and five nitrogen application techniques viz., N0 : Recommended dose of N (60
kg ha-1); N1 : 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 2;N2 : 30 kg N as basal + 15
kg ha-1 N when LCC ≤ 3; N3 : 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 4; N4 : 30
kg N as basal + 15 kg ha-1 N when LCC ≤ 5, laid out in a split-plot (split-split) design
with varieties in the main plots, crop establishment techniques in the sub-plots and
nitrogen application techniques in the sub-sub plots and were replicated thrice.The soil
of the experimental site was sandy loam, acidic in reaction, medium in organic carbon
and available N, low in available P2O5 and K2O. Among the different growth and
physiological parameters viz., plant height, tillers m-2, dry matter accumulation, CGR,
RGR and NAR, the highest values recorded in the variety Ranjit followed by Bahadur
and Gitesh. Similarly, in case of crop establishment techniques and nitrogen application
techniques, SRI and 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 recorded the
highest values in different growth and physiological parameters viz., plant height, tillers
m-2, dry matter accumulation, CGR, RGR, NAR during 2017 and 2018, respectively.
Root volume was also significantly affected by different varieties and was found
to be the highest in Ranjit followed by Bahadur and Gitesh. Similarly, in case of crop
establishment techniques, the root volume was recorded highest in SRI method followed
by transplanting and direct seeding by drum seeder whereas the root volume was found
to be highest in application of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 as
compared to recommended dose of nitrogenin different nitrogen application techniques.
The results from the pooled data revealed that the variety Ranjit recorded
significantly the highest yield attributing characters and grain as well as straw yields of
47.22 q ha-1 and 87.12 q ha-1 during 2017 and 2018. In case of methods of crop
establishment, SRI recorded significantly higher grain and straw yields of 46.54 q ha-1
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and 85.86 q ha-1 as compared to sowing by drum seeder. Application of 30 kg N as
basal + 15 kg ha-1 N when LCC ≤ 5 recorded significantly the highest grain as well as
straw yields of 53.65 q ha-1 and 94.48 q ha-1, respectively as compared to other
treatments. Pooled data of the treatment combinations showed that application of 30 kg
N as basal + 15 kg ha-1 N when LCC ≤ 5 with Ranjit establishing with SRI method
registered significantly higher grain and straw yields over other treatment combinations.
The highest grain and straw yields of rice from the pooled data was recorded with the
application of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 in Ranjit when SRI
method of crop establishment was followed.
The uptake of N, P, K and total uptake had been significantly affected by
different varietal treatments. The highest uptake was found in case of Ranjit followed by
Bahadur and Gitesh. In different crop establishment techniques N, P, K and total uptake
was found to be the highest in case of SRI method followed by transplanting and direct
seeding by drum seeder. Highest uptake was also found in application of 30 kg N as
basal + 15 kg ha-1 N when LCC ≤ 5 in comparison to other treatments.Results from the
apparent nitrogen balance sheet indicated that the highest net gain in available N in soil
was recorded in application of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 in Ranjit
when SRI method was followed during 2017 and 2018, respectively,as compared to
other treatment combinations.
In case of economics, the higher net returns and B:C ratio (1.65 and 1.62) was
recorded under treatment combinations of 30 kg N as basal + 15 kg ha-1 N when LCC ≤
5 with Ranjit and drum seeder method of crop establishment in 2017 and 2018,
respectively.