STUDY ON NITROGEN DOSES IN BORO RICE GROWN WITH VARIABLE LEVELS OF FLOATING DUCKWEED

Abstract

An experiment was carried out at the Agronomy Research Farm of Shere-Bangla

Agricultural University, Dhaka during the period from November 2018 to June 2019 to study on nitrogen requirement of boro rice grown with floating duckweed. Four duckweed treatment viz. D = Control (0 g duckweeds m -2 ), D 1 = 200 g duckweeds m ii -2 = 400 g duckweeds m -2 and D 3 = 600 g duckweeds m -2 and three nitrogen treatment viz. N 1 = 45 kg N ha -1 , N 2 = 90 kg N ha -1 and N 3 , D 2 = 180 kg N ha were applied for this experiment. The experiment was laid out in a Randomized Complete Block Design with three replications where duckweed treatment (Factor A) and was for nitrogen treatment (Factor B). Data on different growth and yield parameters were recorded and analyzed using MSTAT software. Different doses of duckweeds showed significant influence on most of the parameters and D (400 g duckweeds m -2 2 ) treatment the best performance on growth and yield parameters of rice. Among different doses of nitrogen, N 2 (90 kg N ha -1 ) gave the best results on growth and yield parameters of rice. In case of combined effect, D 2 N showed the best results on growth and yield parameters and gave the highest number of tillers hill 2 -1 (16.40), dry weight hill (48.97 g), number of effective tillers hill -1 (14.73) and number of grains panicle (189.50). This treatment combination also showed the highest number of filled grains panicle -1 (183.90), panicle length (25.83 cm), 1000 grain weight (25.13 g), seed yield (7.24 t ha -1 -1 ), straw yield (8.47 t ha ), biological yield (15.71 t ha -1 ) and harvest index (46.09%). On the other hand, D 0 N gave the least results on these parameters. Findings revealed that application of 400 g duckweeds m 3 -2 with 90 kg N ha showed the superiority over other treatment combinations to produce higher grain yield of boro rice.