Potassium nutrition on yield and economics of rainfed finger millet in eastern dry zone of Karnataka

In rainfed agriculture, application of potassium is neglected by most of the farmers in finger millet. Afield experiment was conducted from 2009 to 2011 during kharif at the All India Coordinated Research Project for Dryland Agriculture, GKVK, Bangalore under rainfed situation on deep, yellowish red, sandy loam soils to study the response of finger millet to the application of different grades and time of application of potassium. The studies were also conducted at farmer's field. The results have clearly showed the importance of potassium in finger millet, when applied in conjunction with recommended N (50 kg ha⁻¹) and P (40 kg ha⁻¹). Application of 150% of recommended K (37.5 kg ha⁻¹) to finger millet significantly increased the grain yields (3, 857 kg ha⁻¹) and straw yields (8, 125 kg ha⁻¹), as compared to the yields obtained with the recommended K (25 kg ha⁻¹) application (3, 380 and 7, 651 kg ha⁻¹, respectively). Application of FYM or Gliricidia sepium registered significantly lower grain yield compared to application to 150% of recommended K. Further, when applied as basal dose, it recorded highest benefit: cost ratio and rain water productivity (3.26 and 9.98 kg ha⁻¹ mm, respectively) indicating higher sustainability over other treatments with a sustainability yield index of 0.908. Similar results were obtained on farmers ’field also. Application of potassium more than the recommended dose registered higher NPK uptake at the end of third year. The nutrient balance worked out for NPK was positive when potassium was applied at higher rate as basal dose along with recommended N and P.