Efficacy of Weed Management Techniques on Weed Control, Biomass Yield, and Soil Herbicide Residue in Transplanted Wild Marigold (Tagetes minuta L.) under High Rainfall Conditions of Western Himalaya

A reduced herbicide rate with hand-weeding (HW) can act as a safer and sustainable approach for weed control. A field study was conducted at CSIR-IHBT, Palampur, India during 2018 and 2019 to analyze the efficacy of herbicides in combination with manual weeding on weed control and the yield of wild marigold (Tagetes minuta L). The experiment was laid with 12 treatments, consisting of two herbicide dosages with prescribed and reduced rates (R) of pendimethalin, imazethapyr, and carfentrazone-ethyl, along with integration of reduced-rate herbicide treatments with HW. The weed population, dry matter, and the crop biomass yield had a significant effect on different weed-control treatments. Imazethapyr (R) with HW recorded a reduced weed number (9.64 m(-2)) and weed dry matter (13.64 g m(-2)) and a greater biomass yield (235.03 q ha(-1)). All the herbicides with integration with HW decreased the weed infestation and enhanced the biomass yield. The weed control efficacy of imazethapyr was higher than pendimethalin and carfentrazone-ethyl. Weed infestation in reduced doses of herbicides with HW was lower than in recommended doses. Herbicide residues in the soil of all herbicides at both the dosages were below the detectable limit (< 0.001 mu g g(-1)). Therefore, a reduced dose of imazethapyr integrated with HW can be prescribed to T. minuta growers as a more sustainable approach.

Automated summary

The study indicates that a reduced dose of imazethapyr combined with hand-weeding can significantly reduce the number and dry matter of wild marigold, while increasing biomass yield, making it a more sustainable weed control method.