Optimizing seed metering through drum seeder slot modification in conjugation with seed priming in wet seeded rice (Oryza sativa L.)

Abstract

In recent years, paddy drum seeders have become the tool of choice for rice farmers to deal with the seasonal labour shortage that occurs with the arrival of monsoon. However, the seed rate can go as high as 100 kg/ha with drum seeders because of issues with excess seed drop and uneven dispersion of seeds. In addition, a suitable seed priming method for rice under drum seeder is to be identified to facilitate seed flow through the slot modifications and enhance germination in the main field. Based on this background, innovations in the drum seeder slot modifications were carried out during 2020-21 and 2021-22 at the Department of Agronomy, Agricultural College and Research Institute, Madurai, India. The initial trial was conducted on the seed priming methods comprised of osmo-priming, vitamin priming (Ascorbate), micro-nutrient and hydro-priming at different concentrations and duration of incubation. The best treatment combinations were taken as sub-plot for the two-year field study along with drum seeder slot modifications as the main plot. The drum seeder slot modifications comprised of round slot (RS), oval slot (OS), round slot with guiding strip (RS+GP), and oval slot with guiding strip (OS+GP). The results revealed that drum seeder slots either OS+GP (or) RS+GP since on par successfully reduced the seed rate as low as 24.1 kg/ha, along higher productive tillers (32.6), and higher grain yield (5050 kg/ha) and straw yield (7618 kg/ha). Secondly, the newer seed priming technique involving multi-nutrient mixture @ 0.5% for 24 h (or) vitamin priming using ascorbic acid @ 10 ppm for 48 h increased the overall yield over the conventional hydro-priming (soaking in water for 24 h). However, research into improved drum seeder and seed priming methods is crucial everywhere, but especially in regulated areas where water release is unpredictable.