Effect of foliar application of potassium on yield and quality of Groundnut (Arachis hypogaea L.) in vertisol

A field experiment was conducted during summer 2017 at Agricultural Research Station, Nipani, University of Agricultural Sciences, Dharwad to evaluate the effect of foliar application of different potassium sources, doses and timing on yield and quality of groundnut in Vertisol. The experiment was laid out in randomized block design with fourteen treatments replicated thrice. The treatments consisted of three potassium sources (KCl, K₂SO₄ and KNO₃), two concentrations (1% and 2%), two application times (30 DAS and 60 DAS), water spray control and recommended dose of fertilizer (RDF) alone. Foliar application of 2% K₂SO₄ at 60 DAS along with RDF recorded significantly higher kernel yield (2469 kg ha⁻¹) and pod yield (3417 kg ha⁻¹) compared to water spray with RDF (1616 kg ha⁻¹ kernel yield and 2361 kg ha⁻¹ pod yield) and RDF alone (1559 kg ha⁻¹ kernel yield and 2361 kg ha⁻¹ pod yield). This treatment also resulted in higher oil content (48.37%), oil yield (1194 kg ha⁻¹), protein content (25.38%) and protein yield (627 kg ha⁻¹) with maximum net returns (₹1,14,490 ha⁻¹) and benefit-cost ratio (3.73). The study concluded that foliar application of 2% K₂SO₄ at 60 DAS supplemented with basal RDF is effective for enhancing groundnut productivity and profitability in Vertisol.