Effects of induced potassium deficiency in groundnut and its estimation by flame photometry

Abstract

Groundnut, an economically important oil seed crop is very sensitive in response to nutrient uptake from soil, mainly potassium; a major inorganic plant nutrient. Soil potassium analysis cannot compensate the hidden hunger of crops for potassium, thus calls for a methodology to determine the potassium level directly from plant. In the present study, groundnut was grown in nutrient free medium (marble sand) and nourished with Hoagland Nutrient Solution supplemented with variable levels of potassium, including potassium deficit as one of the treatments. The cultured plants were observed for variation at different growth stages, including plant height, leaf appearance, leaf chlorophyll content and leaf morphology for potassium deficiency symptoms. The potassium level of the leaf sap was determined by flame photometry at 30 days after sowing. Potassium deficiency below 40 mM concentration was observed in the plants at 60 days after sowing.