GROWTH AND YIELD OF BORO RICE AS AFFECTED BY APPLICATION METHOD AND SOURCE OF NITROGEN FERTILIZER

Abstract

The experiment was conducted at the research field of Sher-e-Bangla Agricultural University, Dhaka during the period from November, 2019 to May, 2020 to study the influence of Azolla pinnata as supplementary nitrogen source of boro rice. The trial comprised of two methods of fertilizer application viz. Basal (M 1 ) and five fertilizer sources viz. fresh Azolla pinnata (S 1 ) and top dressing (M 2 ), dry Azolla pinnata (S 2 ii

), 100% Urea (S 3 ), 50% Azolla pinnata + 50% Urea (S 4 ), control (no urea and no Azolla pinnata) (S 5 ). The experiment was laid out in split-plot design with three replications by assigning in fertilizer application methods in the main plot and fertilizer sources in the sub plot. Results revealed that different fertilizer application methods did not significantly influenced most of the growth and yield parameters except plant height at 25 and 45 DAT, panicle length, filled grains, total grain, dry straw weight hill -1 , fresh and dry grain yield, grain-straw ratio, biological yield, pH and total N content in post-harvest soil. The maximum dry grain yield (6.46 t ha -1 ) was recorded from top dressing and the minimum dry grain yield (5.76 t ha -1 ) was recorded from basal application. Significant variation was recorded for fertilizer sources in case of most of the growth and yield parameters except days to maturity, number of ineffective tillers hill -1 and available P content in post-harvest soil. The maximum filled grains and total grains panicle (180.43 and 166.16, respectively) was recorded from 100 % urea application which was statistically similar with 50% urea + 50% Azolla pinnata application. The minimum filled grains and total grains panicle -1 (136.07 and 162.17, respectively) was recorded from 100 % urea application. The maximum weight of 1000–grain (23.56 g) was obtained from 100 % urea application while the minimum weight of 1000-grains (20.17 g) was obtained from 100% dry Azolla pinnata application. The maximum dry grain yield (8.15 t ha -1 ) was recorded from 100% urea

application and the minimum dry grain yield (4.62 t ha ) was recorded from fresh Azolla pinnata application. The interaction of fertilizer application methods and fertilizer sources had no significant effect on days to flowering and maturity, effect on number of ineffective tillers hill , P and K in post-harvest soil that showed the positive indication of replacing chemical fertilizer by Azolla pinnata application.