Effects of potassium and zinc nutrition on yield and quality of forage sorghum

Field studies to determine the effect of potassium @ 20, 40 and 60 kg K₂O ha^”1 and zinc @ 10 and 20 kg zinc sulphate -ZnSO₄ ha^”1 revealed that green and dry forage yields of sorghum were significantly influenced due to the application of K and Zn. Application of K @ 40 and 60 kg K₂O ha⁻¹ increased green and dry forage yields to the extent of 9.8 and 13.1 and 9.7 and 12.9%, respectively. The green and dry forage yields were increased by 6.2 and 10.2 and 5.9 and 9.7% respectively due to ZnSO₄ @ 10 and 20 kg ha⁻¹ in comparison to without Zn application. The highest net return of Rs. 21934 ha¹ and B:C ratio of 2.51 were recorded with combined application of K @ 40 kg K₂O ha⁻¹ and ZnSO₄ @ 20 kg ha⁻¹. Protein content and yield were increased progressively with the increasing K and Zn levels. Application of K significantly enhanced the status of organic carbon and available K in the soil at harvest stage of crop. Available P status in the soil decreased significantly due to application of Zn, while, available of S and Zn were significantly increased due to Zn application.