Herbicide based weed management in aromatic rice of Bangladesh

Abstract

Selection of appropriate weed management strategy helps reduce rice yield loss due to weeds. Despite some undesirable side-effects, no viable alternative is currently available to shift the chemical weed management in rice. However, time of herbicide application is very important with respect to its efficacy. Keeping in mind the inevitability of herbicidal weed control, the current study was designed to evaluate the response of selected aromatic fine rice varieties of Bangladesh to different herbicides based weed management practices compare to farmers' practices. The experiment was conducted in a randomized complete block design with three replications. The experiment consisted of five aromatic rice varieties; Kalijira, BRRI dhan34, BRRI dhan37, BRRI dhan38 and Binadhan-13, and six different weed management practices comprising no weeding, weed free, mechanical + manual weeding, pre-emergence herbicide + manual weeding, post-emergence herbicide + manual weeding and pre-+ post-emergence herbicide. Eleven weed species belonging to five families were observed in the experimental plots. Based on the summed dominance ratio (SDR), grassy weed species Echinochloa crusgalli (SDR of 30.7) was the most dominant species, whereas broadleaf weed Nymphaea nouchali (SDR of 0.83) was the least one. Among the weed control treatments, application of pre-+ post emergence herbicides offered the highest reduction in weed density and biomass at all sampling dates which resulted in minimum crop-weed competition facilitating improvement in the yield contributing characters and finally resulted in the highest grain yield (2.5 t ha −1 ) and harvest index (30.7%) next to the weed free treatment. The variety BRRI dhan38 gave the highest grain yield (3.4 t ha −1 ) due to the highest performance of the yield contributing characters among the varieties. In interaction, BRRI dhan38 with pre-+ post-emergence herbicide application gave the highest yield (3.4 t ha −1 ) apart from the weed free treatment. Being efficient in weed density and biomass reduction as well as the highest yield producer, sequential application of pre-and post-emergence herbicides may be recommended for effective weed management practices in BRRI dhan38.

Effect of different age of seedlings on the growth and yield performance of transplanted Aus rice variety

“…The highest number of effective tillers hill -1 (17.562) was found in BRRI dhan65 where effective tillers hill -1 of BRRI dhan83 was 11.342. Significant variations in number of effective tillers hill -1 among the different varieties were also reported by Islam et al (2018). The highest panicle length (22.688 cm), number of grains panicle -1 (104.177), sterile grains panicle -1 (42.667), and 1000 grains weight (26.573 gm) were obtained from BRRI dhan83 and the lowest panicle length (21.308 cm), number of grains panicle -1 (83.497), sterile grains panicle -1 (33.317) and 1000 grains weight (23.610 gm) were obtained from BRRI dhan65.…”

On-Farm Evaluation of Conservation Agriculture Practice on Weed Control and Yield of Wheat in Northern Bangladesh

“…Compared to the single application of pre-and post-emergence herbicide, the combination of them exerted 70% higher WCE than hand weeding of CT Table 5. The broad-spectrum activity and higher phytotoxic effects of herbicides [37]; [38] against both grass, broad-leaved, and even narrow-leaved weeds compared to a single application of each may explain the higher WCE in SP than CT. Retention of 50% rice straw residue produced lesser weed density and biomass than no-residue.…”

Interaction of Foliar Nutrients and Herbicides Into Production

“…This result explains that the normal fertilization treatment it has an abundant amount of the two basic N and P elements to increase the plant height, while the crop plants remain lower when the fertilizer is not added due to the lack of the necessary mineral elements necessary for growth in the soil of the experiment except with a small amount that does not enable it to grow at its full potential. These results did not in agreement with Osman et al (20) and Kheyri et al (18) who indicated that organic and mineral foliar fertilizers lead to a significant increase in plant height compared to the normal fertilization treatment, nor are they consistent with Aljutheri et al (4) who They indicated that there were no significant differences between mineral and organic foliar fertilizers compared to normal fertilization.…”