Efficacy evaluation of two-row paddy power weeder and brush cutter attached rotor with manual rotary weeder for paddy cultivation in Thiruvananthapuram district

Paddy farmers in Thiruvananthapuram district predominantly rely on manual weeding for weed management in paddy fields. The commonly observed weed flora in the region includes Digitaria ciliaris (Retz.) Koeler, Cyperus difformis L., Eleocharis spp. and Monochoria vaginalis (Burm.f.) C.Presl ex Kunth, the efficacy of mechanical weeding for Eichhornia crassipes (Mart.) Solms is critically dependent on the total extraction of all plant tissues, as incomplete removal triggers rapid clonal expansion through vegetative propagation. To evaluate the effectiveness of different weeding methods, Krishi Vigyan Kendra (KVK) conducted field trials at 30 days after transplanting (30 DAT) over a 1.5 ha paddy field at Varkala, a suburb of Thiruvananthapuram district, Kerala. The treatments comprised the manual paddy finger-type rotary weeder (T1- Technology option 1), brush cutter-attached rotor (STIHL) (T2- Technology option 2) and two-row paddy power weeder (TNAU model- Tamil Nadu Agricultural University) (T3 - Technology option 3). Mechanised transplanting was adopted with a spacing of 21 cm between plants and 30 cm between rows to facilitate efficient operation of mechanical weeders between crop rows. The 21 × 30 cm spacing used with the Kubota transplanter is optimal because the 30 cm row width exactly matches the mechanical weeder's rotors, preventing crop damage and facilitating efficient inter-row weeding. Among the tested implements, the brush cutter was found to be cumbersome, as it had to be carried on the operator’s shoulders, making its operation difficult under puddled field conditions. In contrast, the two-row paddy power weeder (T3) exhibited superior performance, recording a field capacity of 0.067 ha hr-1, weeding efficiency of 81.5 % and field efficiency of 95.71 %. The implement (two-row paddy power weeder powered by a four-stroke engine) at 0.55 L hr-1 also demonstrated lower fuel consumption (0.55 L hr-1) and reduced labour requirement (15 man-hr ha-1), while causing minimal crop damage (2 %). The grain yield obtained was 79.24 q ha-1, with a benefit-cost ratio of 2.12. Overall, the two-row paddy power weeder proved to be highly effective in covering larger areas with minimal inputs, leading to significant improvements in productivity and farmers’ income.