Pre-emergence herbicide selection for successful cultivation of black seed (Nigella sativa L.), psyllium (Plantago ovata Forsk), and quinoa (Chenopodium quinoa Willd.)

Weed control in black seed, psyllium, and quinoa is of huge importance for successfully cultivating and adapting these medicinal and nutritious crops. The recent study was designed to evaluate the pre-emergence herbicides (S-metolachlor and pendimethalin) for their possible application in these crops. The study consisted of three experiments on each crop for two years (2020–21, 2021–22). In each experiment, herbicides and their incremental doses (0 %, 25 %, 50 %, 75 %, and 100 % of recommended label dose) were applied under a randomized complete block design under the factorial arrangement. Data on weed dynamics, crop agronomic, and yield attributes were collected. Results revealed that the weed control efficiency of both herbicides ranged from ∼60–80 %. Crops, on the other hand, varied in their tolerance to both herbicides. Pendimethalin proved to be more detrimental for all the crops. Dose-response curves showed the crop tolerance to pendimethalin and can be ranked as black seed>psyllium and quinoa. Contrastingly, all the crops showed tolerance to the incremental dose of S-metolachlor. Crops tolerance to S-metolachlor can be ranked as black seed>quinoa>psyllium as per their respective Ed₅₀ values. The study concluded that pendimethalin use in these crops should be avoided. However, S-metolachlor can be employed as a pre-emergence herbicide in the cultivation of black seed, psyllium, and quinoa at the recommended label dose.