Effect of graded levels of NPK on fresh herb yield, oil yield and oil composition of six cultivars of menthol mint (<i style="">Mentha arvensis</i> Linn.)

Abstract

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A field experiment was conducted for two years during 2002-2003 and 2003-2004 to evaluate the influence of different levels of NPK on herb and oil yield of different cultivars of menthol mint (<i>Mentha arvensis</i> Linn.). The treatments were combinations of five levels of NPK, viz. control (F₀): F₁: N₅₀P₂₀K_20,F₂: N₁₀₀P₄₀K_40,F₃: N₁₅₀P₆₀K₆₀ andF₄: N₂₀₀P₈₀K₈₀, and six cultivars of menthol mint, viz. ‘Kosi’, ‘Himalaya’, ‘Saksham’, ‘Kalka’, ‘Kushal’ and ‘Shivalik’. Average increases in fresh herb yield of menthol mint were 5.8, 10.2, 16.3 and 21.1% over control (F₀), with F₁, F₂, F₃, and F_4,respectively. The increase in herb yield of menthol mint with the highest dose of NPK (N₂₀₀P₈₀K₈₀) over control was 38.7, 13.6 12.2, 15.6, 22.2 and 25.9% with cvs. ‘Kosi’, ‘Himalaya’, ‘Saksham’, ‘Kalka’, ‘Kushal’ and ‘Shivalik’, respectively. Cultivar ‘Saksham’ produced highest oil (312.4 l/ha) followed by cvs. ‘Kosi’, ‘Shivalik’, ‘Himalaya’, ‘Kushal’ and ‘Kalka’. Essential oil yield increased with increasing NPK levels. The maximum increase in oil yield was with the application of 150 kg N, 60 kg P and 60 kg K and the extent of increase were 59, 23, 38, 33 and 30% in ‘Kosi’, ‘Himalaya’, ‘Saksham’ and ‘Shivalik’, respectively. Oil quality was not affected by NPK levels in different cultivars of menthol mint.

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