Weed Dynamics and Productivity of Fodder Sorghum as Influenced by Intercropping and Herbicidal Weed Management Strategies under Semi-Arid Agro-ecology

Abstract

Sorghum, known for its resilience and adaptability to various climates as a cereal crop, has also become important as a fodder crop due to its broad adaptability. However, it remains highly vulnerable to numerous weed species. In order to manage weeds, field experiment was designed during the Kharif season of 2021-22 at Instructional Farm, Rajasthan College of Agriculture, Udaipur to evaluate weed management in kharif fodder sorghum. The experiment was laid out in a randomized block design with twelve treatments replicated thrice. The treatment combinations are Atrazine 50% WP @ 0.50 kg a.i ha-1 as PE (T1), Metolachlor 50% EC @ 1.00 kg a.i ha-1 as PE (T2), Pyroxasulfone 85% w/w WG @ 0.1275 kg a.i ha -1 as PE (T3), 2,4-D Na salt 80% WP @ 0.75 kg a.i. ha-1 as PoE at 20 DAS (T4), T1 + Atrazine 50% WP @ 0.50 kg a.i. ha-1 as PoE (T5), T1 + 2,4-D Na salt 80% WP @ 0.75 kg a.i. ha -1 as PoE at 20 DAS (T6 ), intercropping with cowpea (1:1 additive series) without herbicides (T7), intercropping with cowpea (1:1 additive series) + Pendimethalin 30% EC @ 0.75 kg a.i. ha-1 as PE (T8), intercropping with blackgram (1:1 additive series) without herbicides (T9), intercropping with blackgram (1:1 additive series) + Pendimethalin 30% EC @ 0.75 kg a.i. ha-1 as PE (T10), weed free (two hand weeding at 15 and 35 DAS) (T11) and weedy check (T12). The efficacy of the weed management using different treatments was evaluated among different weed flora, weed dry matter T₅ showed the most effective weed control, significantly reducing grass, sedge, and broad-leaved weed populations and dry matter by up to 74.87%. It maintained low weed indices (0.28%), nearly matching manual weeding, and improved fodder sorghum yield. Atrazine-based T₅ proves effective for managing diverse weeds in semi-arid conditions.