Weed seed bank and weed population as influenced by weed management practices in rice var Co 54

Abstract

Weed seed bank in soil serves as the reservoir of weed seeds which emerge whenever conditions become conducive and affects crop growth. In the present study, a field experiment was performed at Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai, India, during Kharif 2021 and Rabi 2022 to determine weed seed bank present in soil by direct seed extraction using the sieving method at discrete depths of 0-5 cm, 5-10 cm and 10-15 cm after rice harvest with reference to different weed management practices imposed and its effect on weed population in succeeding crop. The average proportion of weeds that emerged in the field ranged from 9 to 38 % of the total weed seed bank. Weed management practices followed during the preceding crop greatly influenced weed seed germination. The higher weed seed reserve (1384 m-2) and consequent weed population (528 no’s m-2) were found at a depth of 0-5 cm in unweeded plots. The lower weed seed density (536 m-2) and weed population (94 no’s m-2) were found in pre emergence application of Pyrazosulfuron + Pretilachlor and early post emergence application of Bispyripac sodium. The results from the present study confirmed that herbicide treatment considerably minimized the weed seed density and population, which will assist in predicting weed infestation and appropriate timing of weed control.