Lutfun Nahar*
Agronomy Division, Bangladesh Rice Research Institute, Joydebpur, Gazipur-1700, Bangladesh
Rakiba Shultana
Agronomy Division, Bangladesh Rice Research Institute, Joydebpur, Gazipur-1700, Bangladesh
Khairul Alam Bhuiyan
Agronomy Division, Bangladesh Rice Research Institute, Joydebpur, Gazipur-1700, Bangladesh
Md. Zakaria Ibne Baki
Agronomy Division, Bangladesh Rice Research Institute, Joydebpur, Gazipur-1700, Bangladesh
Romana Akter
Agronomy Division, Bangladesh Rice Research Institute, Joydebpur, Gazipur-1700, Bangladesh
Crop residues, Herbicide, Weed control efficiency, Transplanted Aman rice, Allelopathic phenomenon, Phytotoxicity
At Net house of Agronomy Division of Bangladesh Rice Research Institute (BRRI), Joydebpur, Gazipur1701
Pest Management
Weed management
Experimental site The research study was conducted at Net house of Agronomy Division of Bangladesh Rice Research Institute (BRRI), Joydebpur, Gazipur1701 belongs to Agro ecological Zone (AEZ-15) during T. Aman season 2016 to evaluate weed control efficiency (WCE) of different crop residues and pre-emergence herbicide (Butachlor). The geographic coordinates of the research studied area was located between two Experimental design and crop residues incorporation The experiment was conducted complete randomized designed with three replications with five weed control treatments viz. chopped (2-3 cm) crop residues of sorghum (T1), Chopped (2- 3 cm) crop residues of soybean (T2), chopped (2-3 cm) crop residues of mungbean (T3), chopped (2-3 cm) crop residues of rice (T4), preemergence herbicide (Butachlor) (T5) and control (no weed management method) (T6) was imposed in this experiment for comparison. The pot size was one square meter. Collection and application of crop residues and herbicide Before going to initiate net house research, field-grown harvested disease and insect damage free mature plants of sorghum, soybean, mungbean (except consumed part) were collected from the Bangladesh Agricultural Research Inst tut ’s (BARI) research plot. The crop residues were chopped about 2 to 3 cm pieces with a fodder cutter. Crop residues were incorporated @ 5.0 t ha-1. As per treatment schedule whole plant residues were mixed in soil three days after transplanting. In the same day pre-emergence herbicide (Butachlor) was applied @ 25 g ha-1. Selection of cultivar and planting methods Planting crop was BRRI dhan72. Thirty- daysold seedling was transplanted to maintain row to row and hill to hill distances of 20 cm on 15th June 2016. Fertilizer Application rate and methods The experimental plots were fertilized @ of 69- 11-41 and 10 kg ha-1 N-P-K and S respectively according to BRRI recommended dose. The whole amount of TSP, MoP and Gypsum and one third of urea was applied during the final pot preparation. Remaining urea was top dressed at 15 and 30 days after transplanting. Observation of weed flora in net house experiment To account the general weed flora of the net house experiment, species wise observations were carried out at 30 days after transplanting from randomly selected quadrates (0.5 m × 0.5 m) from each experimental pot. Weed density Weed density (m-2 ) was counted by using 0.5 m × 0.5 m quadrant from randomly fixed places in each pot and the weeds falling within the frames of the quadrant were counted and the mean values of different weed species were expressed in number m-2.
Weed dry weight Weeds are falling within the 0.5 m × 0.5 m quadrant were collected at 30 days after transplanting (DAT) and these were firstly dried in shade and then an oven at 70 °C for 48 h. The collected weight was expressed as g-2.
Biological yield Biological yield was calculated by using following formula. Biological yield= Grain yield + straw yield. Harvest index Harvest was calculated by using following formula. HI (%) = (Grain yield ÷ Biological yield) × 100. Weed index Weed index (WI) was calculated as per Gill et al., (1969).
Weed index = ( X-Y) / X 100
Where, X = Yield (t ha-1 ) from minimum weed competition plot, Y=Yield (t ha-1 ) from the treatment plot for which WI is to be worked out.
Harvesting and data collection Prior to harvesting of crops five hills from each pot were selected randomly to determine the yield contributing yield contributing characters. To determine the yield data (t ha-1) crop was harvested whole plot basis, tied into bundles in respective plots and was manually threshed to determine grain yield and is reported on t ha-1 basis. Grain weight of five hills also added with whole plot yield.
Statistical Analysis The collected yield and yield contributing data w r yz us “MSTATC” st tistical software and least significance difference (LSD) at 0.05 probability was employed to compare the differences among treatments means. To determine weed parameter mean values of different weed species were incorporated under this experiment.
International Journal of Applied Research 3(3) 7-13; Sept. 2017
Journal