INFLUENCE OF AGRONOMIC MANAGEMENTS ON GROWTH AND YIELD OF BORO RICE

Abstract

The experiment was conducted at the experimental field of Sher-eBangla

Agricultural University, Dhaka during the period from December, 2018 to April 2019 to study the influence of agronomic managements on growth and yield of Boro rice. The experiment comprised of two factors having two varieties viz. BRRI dhan84 (V ), and BRRI hybriddhan5 (V ) in the main plots and seven agronomic managements viz. no management (M 2 ), no weeding but all other managements (M 1 0 ), no fertilizer application but all other managements (M ), no irrigation in reproductive and ripening stage but all other managements (M 2 3 ), no insecticides but all other managements (M ), no fungicides/ bactericides but all other managements (M ) and complete managements (M 6 5 ) in the sub-plots with three replications. Significant variation was recorded for weed severity, different yield contributing characters and yield of Boro rice. The lowest weed population (13.83 m 2 ) was recorded in M 4 and weight of weed biomass (2.81 g m ) was recorded in M 6 , whereas the highest weed population (144.83 m ) was found in M 0 (no management) but the highest weight (77.17 g m ) was found in the M treatment. The tallest plant of 24.81 cm, 51.56 cm, 86.71 cm and 119.21 cm were recorded at 20, 45, 70 DAT and at harvest, respectively. Higher grain yield (5.36 t ha 1 -1 ) and lower straw yield (4.97 t ha -1 ) were recorded from V 2 compared to that of V . Irrespective of agronomic managements, the higher plant height was given by BRRI dhan84 except no management. The highest grain yield (6.70 t ha 1 ) was observed from M 6 and the highest straw yield (6.55 t ha -1 . In respect of interaction, the highest grain yield (7.35 t ha -1 ) were observed from V 2 M 6 where V 2 M 5 statistically identical and V 1 M 4 -2 -2 -2 -1 ) from M , V , V 2 M 3 , V 2 M 4 statistically similar and highest straw yield (7.37 t ha ) were observed from V 1 M 4 where V 1 M 3 , V 1 M 6, V 2 M 3 , V 2 M statistically similar, while the lowest grain yield (1.00 t ha -1 ) from V and straw yield (2.07 t ha -1 ) from V 2 M 0 1 . Irrespective of variety, the highest yield reduction in BRRI dhan84 was 84% in no management that followed by 80% in no fertilizer treatments whereas the rate was 71% for BRRI hybriddhan5 of Boro rice.