Effect of rate and source of zinc on yield, quality and uptake of nutrients in Indian mustard (Brassica juncea) and soil fertility

A field experiment was conducted in two consecutive rabi seasons of 2012-13 and 2013-14 at Panwari village, Agra (Uttar Pradesh) to study the effect of rate and source of zinc on productivity, quality and uptake of nutrients in Indian mustard (Brassica juncea (L.) Czern and Cosson). The experiment was laid out in randomized block design with two sources (zinc oxide and zinc sulphate) and five levels of zinc (0, 2, 4, 6 and 8 kg Zn/ha) with three replications. The results indicated that significantly taller plants and higher number of sliquae/plant, seed and stover yields were obtained with zinc sulphate as compared to zinc oxide. The plant height, yield attributes, i.e. siliquae/plant, seeds/siliqua and test weight, seed and stover yields of mustard were significantly improved with the increase in the levels of zinc and the highest seed (19.22 q/ha) and stover (55.77 q/ha) yields were recorded with 6 kg Zn/ha. Application of 6 kg Zn/ ha resulted in 22.2% higher seed and 24.7% stover yield than the yield obtained in the control (16.86 q/ha seed and 48.60 q/ha stover). The content and yields of protein and oil remained unaffected by sources of zinc but increased significantly with increasing Zn doses, thus mustard fertilized with 6 kg Zn/ha recorded the highest yield of protein (384.0 kg/ha) and oil (39.3%, 754.7 kg/ha). The maximum value of protein content (21.0%) was recorded with 8 kg Zn/ha. The uptake values of N, P, K and S by mustard seed and straw were not affected with source of zinc but zinc uptake increased significantly with zinc sulphate over zinc oxide. The uptake of nutrients in mustard crop increased significantly up to 6 kg Zn/ha followed by reductions at 8 kg Zn/ha. Nutrient status in post harvest soil was not affected with sources of zinc but improved significantly with Zn levels. The status of available N and Zn improved significantly up to 8 kg/ha, whereas P, K and S contents increase up to 4 kg Zn/ha.