Effects of crop establishment techniques and weed management practices on root phenology and grain yield of rice (Oryza sativa L.)

A field experiment was conducted at wetland farms, Tamil Nadu Agricultural University, Coimbatore, India during rabi seasons of two years 2011-12, 2012-13 to study the root characteristics of rice under different establishment techniques and weed management practices. Results revealed that the root dry weight, root volume, root length and root length density were recorded higher values in SRI machine transplanting than conventional system at all growth stages during both the years of investigation. Similarly in case of weed management practices, the above said root growth parameters of rice, also expressed significantly higher values at various observational growth stages when crop made free with conoweeding 4 times at 10, 20, 30 and 40 DAT over unweeded control during both years of field study. The treatment combination of mechanical transplanting with four conoweeding at 10 days interval starting from 10 DAT registered significantly higher values for growth characters and yield attributes, and resulted in higher grain yield, which is comparable with mechanical transplanting with pretilachlor (0.75kg ha-1PE ) + bispyribac sodium (20g ha-1 EPOE) + conoweeding at 40 DAT.