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The experiment was conducted at the Agronomy Field Laboratory of Bangladesh Agricultural University during the period from July to December 2017 to evaluate the effect of barley crop residues on weed management and yield of transplant aman rice. The experiment consisted of three time of crop residue application viz. one week before transplanting, at the time of transplanting, at one week after transplanting and five doses of barley crop residues such as no crop residues, barley crop residues @ 0.5 t ha-1, barley crop residues @ 1.0 t ha-1, barley crop residues @ 1.5 t ha-1, and barley crop residues @ 2.0 t ha-1. The experiment was laid out in a split plot design with three replications. Weed population and weed dry weight were significantly affected by the dose and time of barley crop residues application. The minimum weed growth was noticed with the application of barley crop residues @ 2.0 t ha-1 at one week after transplanting and the maximum one was observed in no crop residues treatment at one week before transplanting. The highest values of percent weed inhibition was found with the application of barley crop residues @ 2.0 t ha-1 which were 48.13%, 41.39%, 39.71%, 39.88% and 38.73% for panikachu (Monochoria vaginalis), shama (Echinochloa crusgalli), chesra (Scirpus juncoides), amrul (Oxalis corniculata) and sabujnakful (Cyperus difformis), respectively. Rice grain yield and the yield contributing characters produced by the application of crop residues at one week before transplanting was the highest among different times of application and the highest reduction of rice grain yield was obtained in no crop residue treatment. The highest number of effective tillers hill-1, number of grains panicle-1, 1000-grain weight, rice grain and straw yields were observed when barley crop residues were applied @ 2.0 t ha-1 at one week before transplanting. Results of this study indicate that application of barley crop residues @ 2 t ha-1 at one week before transplanting showed the maximum suppression of weed growth. Therefore, barley crop residues might be used as an alternative tool for weed management in transplant aman rice. Progressive Agriculture 31 (2): 119-129, 2020

A field experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh from July 2016 to December 2016 to find out the effect of seedlings age and different nitrogen (N) levels on the yield performance of transplant Aman rice (cv. Binadhan-15). The experiment comprised four ages of seedlings viz., 15 , 20 , 25, 30 day old and four levels of nitrogen viz., 0 ,55 , 75 and 95 kg N ha–1 following randomized complete block design (RCBD) with three replications. The effect of age of seedling, nitrogen levels and their interactions were significant on growth, yield and yield contributing characters of transplant Aman rice. The highest plant height at harvest (92.67 cm), number of effective tillers plant–1 (8.70), grain (4.55 t ha–1) and straw yields (5.49 t ha–1) were obtained from 75 kg N ha–1. By using optimum seedling age at 15 DAT the highest plant height (102.7cm at harvest), number of effective tillers plant–1 (8.29), grain (4.01 t ha–1) and straw (5.06 t ha–1) yields. In interaction, 75 kg N and 15 days old seedling produced highest plant height (106.3 cm at harvest), number of effective tillers plant–1 (9.42), grain (5.0 t ha–1) and straw yields (6.10 t ha–1). From the above results of the present study, it may be stated that Binadhan-15 is grown successfully for obtaining maximum yield with 75 kg N ha-1 and 15-day old seedling age individually or in combination.

To investigate the effect of different plant residues on weed inhibition and yield of transplant aman rice, an experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during June 2017 to December, 2017. The experiment comprised of three rice cultivars i.e. BR11, BRRI dhan34 and BRRI dhan49 and five different plant residues treatment viz., no crop residues (control), soybean, wheat, bishkatali and sorghum crop residues @ 2.0 t ha-1 of each. The experiment was laid out following randomized complete block design with three replications. Weed population and weed dry weight were significantly affected by cultivars and crop residues treatment. The highest percent inhibition of 58.31%, 46.84%, 66.85%, 66.94% and 57.6% was in Panikachu (Monochoria vaginalis), Shama (Echinochloa crusgalli), Chesra (Scirpus juncoides), Sabujnakful (Cyperus difformis) and Amrul (Oxalis corniculata), respectively caused by sorghum crop residues. The grain yield, as well as the yield contributing characters produced by BR11,was the highest among the studied varieties. The highest number of effective tillers hill-1 (8.41), number of grains panicle-1(118.08) and 1000-grain weight (20.54 g) were observed in sorghum crop residues. BR11 under sorghum crop residues @ 2.0 t ha-1 produced the highest grain (5.76 t ha-1) and straw yield (6.39 t ha-1). So, to reduce herbicide use in the present situation of Bangladesh, natural herbicide or crop residues like sorghum might be used as an alternative way for weed management for effective and sustainable rice production.

Sunflower (Helianthus annuus) is one of the strongest allelopathic crops through incorporation of its residue in soil to control weed. An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, during the period from June to December 2017 to evaluate the effect of sunflower crop residues on weed management and performance of transplanted aman rice. The experiment consisted of four cultivars i.e; BRRI dhan57, Binadhan-7, Binadhan-15 and Binadhan-16 and four sunflower residues treatment such as 0, 0.5, 1.0, 2.0 t ha-1. The experiment was laid out in a randomized complete block design (RCBD) with three replications. Five weed species belonging to four families infested the experimental plots. Weed population and weed dry weight were significantly affected by cultivar and crop residues treatment. The highest percent weed inhibition was found in sunflower crop residues at 2 t ha-1 treatment which was 47.29, 52.03, 51.28, 71.41 and 70.44 percent for Shama (Echinochloa crusgalli), Amrul(Oxalis corniculata L.), Panikachu(Monochoria vaginalis, Sabuj nakful(Cyperus difformis) and Chesra (Scirpus juncoides), respectively. The maximum weed growth was noticed with the cultivar BRRI dhan57 variety and the minimum was found in the cultivar Binadhan-16. The grain yield as well as the yield contributing characters produced by Binadhan-16 was the highest among the studied varieties. The highest reduction of grain yield was obtained in no crop residue treatment. The highest number of effective tillers hill-1, number of grains panicle-1, 1000-grain weight, grain and straw yields were observed in sunflower residues at 2.0 t ha-1 treatment. Binadhan-16 produced the highest grain and straw yields with sunflower residues 2.0 t ha-1 treatment. Results of this study indicate that sunflower residues showed potentiality to inhibit weed growth and it has a significant effect on the yield of transplanted aman rice. Therefore, sunflower residues might be used as an alternative way for weed management effective as well as obtaining higher yield of T. aman rice. [J Bangladesh Agril Univ 2020; 18(3.000): 557-564]

An experiment was conducted at Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the effect of integration of herbicide with manual weeding on the performance of transplant aman rice cultivars during the period from July to November 2017. The experiment consisted of three transplant aman rice cultivars viz., BR11, BRRI dhan49 and Binadhan7 with seven weeding treatments viz., no weeding (W0), two hand weedings at 15 and 30 DATs (W1), application of pre-emergence herbicide Pretilachlor (W2), application of early post emergence herbicide Acetachlor + Bensulfuron methyl (Pediplast) (W3), application of Pretilachlor followed by application of Pediplast (W4), application of Pretilachlor followed by one hand weeding at 30 DAT (W5) and application of Pediplast followed by one hand weeding at 30 DAT (W6). The experiment was laid out in a randomized complete block design with three replications. Weed density and dry weight were significantly affected by cultivars and weeding treatments. The maximum weed growth was noticed with the BR11 and the minimum with cultivar BRRI dhan49 at 20 DAT. The highest weed density and dry weight were noticed in no weeding treatment and the lowest value was found in application of Pediplast followed by one hand weeding at 30 DAT. Cultivar and weeding treatment exerted significant effect on yield and yield attributes of transplant aman rice. BRRI dhan49 produced the highest grain yield which was statistically identical with BR11 and Binadhan7 produced the lowest grain yield. Application of Pediplast followed by one hand weeding at 30 DAT produced the highest grain yield which was statistically identical with other weeding treatments except no weeding. Rice cultivar BRRI dhan49 with the application of Pediplast followed by one hand weeding at 30 DAT produced numerically the highest grain yield. From the economic analysis, it is observed that the highest BCR was recorded from the application of application of Pediplast with BRRI dhan49. Therefore, application of early post emergence herbicide Pediplast with the cultivar BRRI dhan49 is effective and economic than the other weed control treatments in controlling weeds effectively in producing higher grain yield as well obtaining highest economic return. [J Bangladesh Agril Univ 2020; 18(2.000): 340-346]