Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
T2a-21P-1243
Effect of Different Sowing Dates and Nitrogen Levels on the Productivity of
Wet-Seeded kharif Rice under Post-Flood Situation in Assam
K. S. Teja, K. Kurmi, K. Pathak, J. Goswami and A. Hazarika
Department of Agronomy, Assam Agricultural University, Jorhat, Assam, India, 785013
Rice (Oryza sativa L.), the world's important crop, is the primary food source for nearly half
of the world's population. The total area under rice cultivation in Assam is 23.60 lakh
hectares with a production of 52.60 lakh tonnes and productivity of 2,228 kg/ha. The
optimum time of transplanting of sali or kharif rice under the agro climatic conditions of
Assam is from the first week of July to the middle of August with 30-35 days old seedlings of
long duration varieties. But, in practice, farmers of the state cannot complete transplanting
within the optimum period due to many reasons and one of them being flood in the low-lying
areas of Assam. High intensity of rainfall during the peak period of transplanting often
submerges the crop resulting in partial or complete crop damage. These factors demand a
major shift from puddled transplanting to wet direct seeding of rice with shorter duration high
yielding photoperiod insensitive stress tolerant varieties in puddled condition. Since rice yield
and quality are not only controlled by the method of establishment but are also largely
influenced by environmental factors (Shimono et al., 2002), which can be manipulated to
optimum level through different management practices of which sowing date and nitrogen
fertilization are of prime importance. The right sowing date ensures vegetative growth during
a period of satisfactory temperature and high levels of solar radiation (Farrell et al., 2003).
The absence of transplanting shock in wet-seeded rice results in rapid vegetative growth
during the early growth period and this results in N deficiency at the reproductive phase.
Insufficient and inappropriate fertilizer nitrogen management may result in one half to two
thirds of the gap between actual and potential yields. Therefore, the experiment was
conducted considering the importance of dates of sowing and nitrogen management in
delayed sali rice in Assam.
Methodology
A field experiment was conducted in Assam Agricultural University, Jorhat, Assam during
the kharif season of 2020 and 2021. The experiment was laid out in split-plot design
comprising twenty treatment combinations with four dates of sowing viz., 10 th August, 20 th
August, 30 th August and 9 th September in main plots and five levels of nitrogen viz., 40 kg,
60 kg, 80 kg, 100 kg and 120 kg ha -1 in sub plots. The rice variety used as a test crop was
Bina dhan-11. Fertilizer was applied in the form of urea, single super phosphate and muriate
of potash in both the years. All the data pertaining to the present investigation were
Climate resilient agriculture for risk mitigation
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