Weeds and cultivated plants vie for growth, yet the most detrimental phase for crops occurs during the essential timeframe of competition between weeds and crops, specifically in sugarcane from 30 to 90 days. Cultural approaches to managing weeds are very successful; however, challenges arise due to the restricted access to farming labour during important weeding times and the high costs associated with hiring workers. As a result, chemical methods for weed control are gaining increased acceptance. A field experiment was conducted during the
Suru season of 2024 at the Research Farm, Regional Sugarcane and Jaggery Research Station, Shiroli (
Pulachi), Kolhapur, Maharashtra to evaluate the efficacy of novel herbicidal combinations for effective weed control in sugarcane (
Saccharum officinarum L.) and their impact on nutrient uptake and soil fertility under sub-montane conditions. The study focused on the performance of different weed management practices against prevalent weed flora comprising
Dinebra retroflexa,
Brachiaria eruciformis,
Echinochloa colona (grasses);
Amaranthus viridis,
Parthenium hysterophorus,
Ipomoea spp.,
Portulaca oleracea (broad-leaved weeds); and
Cyperus rotundus L. (sedge).
The results indicated that nutrient concentrations (N, P, and K) in both sugarcane and weed biomass did not differ significantly across treatments. However, the total nutrient uptake by sugarcane was highest under the weed-free treatment, reflecting improved growth and nutrient assimilation compared to the weedy check. Among herbicidal treatments, the post-emergence application of 2,4-D sodium salt + metribuzin + Pyrazosulfuron ethyl (ready mix) @ 3.0 kg a.i. ha-¹ at the 2-4 leaf stage of weeds followed by earthing-up at 120 days after planting (DAP) (T3) recorded the lowest nutrient depletion by weeds. This was closely followed by the pre-emergence application of clomazone (30% WP) + sulfentrazone (28% WP) @ 2.5 kg a.i. ha-¹, supplemented by one inter-cultivation operation at 60 DAP (T2). Treatment T3 proved most effective in optimizing nutrient use efficiency and minimizing competition from weed flora, thereby supporting better crop growth and sustaining soil fertility.
