Influence of zinc and sulphur on growth and yield attributes of Indian mustard (Brassica juncea L.) under Doon valley conditions

In India, mustard (Brassica juncea L.) is a vital rabi oilseed crop, especially in mid-altitude areas like the Doon Valley. The average productivity in Uttarakhand (858 kg ha⁻¹) and India (1499 kg ha⁻¹) is low despite its potential because of mineral deficiencies, particularly in zinc (Zn) and sulfur (S). Zinc is essential for photosynthesis, nitrogen metabolism, and enzyme activation, whereas sulfur aids in protein synthesis, enzymatic processes, and oil content. In order to assess the impact of S and Zn on the growth and yield characteristics of mustard (variety HY-805), a field study was carried out during the 2023-24 rabi season at the Agronomy Research Farm, Jigyasa University, Dehradun. Eight treatments were set up in a factorial Randomized Block Design with three replications, comprising the recommended amount of fertilizer (RDF: 60 kg N, 40 kg P, 40 kg K ha⁻¹) either by itself or in combination with Zn (10-12 kg ha⁻¹) and S (25-75 kg ha⁻¹). Test weight, number of siliquae per plant, number of seeds per siliqua, dry matter accumulation, plant population, and plant height were all noted. With the highest plant population (193.67 plants/plot), plant height (148.54 cm), dry matter accumulation (43.65 g/plant), number of siliquae (37.57/plant), seeds per siliqua (16.38), and test weight (3.60 g) recorded in RDF + Zn 12 kg/ha + S 75 kg/ha, the results demonstrated that the combined application of Zn and S significantly enhanced growth and yield attributes. Additionally, intermediate treatments outperformed control and RDF alone. According to the study, assimilate partitioning, vegetative growth, and reproductive development are all enhanced by balanced Zn and S supplementation, which paves the way for increased mustard output in the Doon Valley.