Effect of Brown Manuring on Growth, Physiology and Yield in Direct Wet-Seeded Rice

This study evaluates the effect of brown manuring on growth parameters, physiological attributes, and yield in direct wet-seeded rice through a field experiment conducted during the rabi season of 2024 at the Instructional South Farm of Karunya Institute of Technology and Sciences, Coimbatore. The experiment followed a Randomized Block Design (RBD) with ten treatments and three replications, comparing rice alone with different brown manuring treatments. The results indicated no significant differences observed among the treatments at 30 DAS. At 60, 90 DAS and at harvest, the weed-free check (T9) recorded the highest growth parameters viz., plant height (117.2, 141.5 and 139.0 cm), tiller count (26, 33 and 31 tiller hill-1), and dry matter production (4276, 13732 and 23132 kg ha-1), physiological attributes viz., Leaf Area Index (3.65, 5.81 and 3.08), Crop Growth Rate (3.84, 11.60 and 9.08 g m-2 day-1), and Relative Growth Rate (0.0572, 0.0431 and 0.0229 g g-1day-1) and yield were also significantly higher with a grain yield (6046 kg ha-1) and straw yield (10801 kg ha-1), which was statistically on par with T6 (pretilachlor 50% EC at 1.25 L ha-1+ knockdown of dhaincha using 2,4-D 38% EC at 1 kg ha-1 at 30 DAS) over the unweeded control (T10). This study concludes that integrating brown manuring with a post-emergence herbicide effectively suppressed weeds while the decomposed dhaincha residue served as a growth stimulant, ultimately improving crop growth and yield in direct wet-seeded rice.