Response of soil applied lignite coal derived humic acid on yield and quality of spinach (Spinacia oleracea L.)

Abstract

A pot experiment was carried out in the net house of the Department of Soil Science & Agricultural Chemistry, Banaras Hindu University, Varanasi, Uttar Pradesh during rabi season of 2017-2018, to study the effect of lignite coal derived humic acid (HA) on growth and development of spinach (Spinacia oleracea L.) in an Inceptisol of Varanasi, Uttar Pradesh with six doses of lignite coal originated humic acid [ i.e. 0.0 (H0), 0.5 (H1), 0.75 (H2), 1.5 (H3), 2.5 (H4) and 5.0 (H5) mg HA kg-1 of soil] and four doses of N (urea) fertilizer [0.0 (N0), 18.50 (N1), 27.80 (N2) and 37.0 (N3) mg kg-1 soil] in different combination. The plant growth parameters (viz. no. of leaves, fresh weight & dry weight) and biochemical parameters (viz. brix value, chlorophyll, nitrogen and protein content) were taken at 30, 45 and 60 days after sowing. The highest values of yield and quality parameters was recorded in the treatment, where higher level (5 mg kg-1 soil) of humic acid was applied with full dose of nitrogen (37.0 mg kg-1 soil) through urea fertilizer. The application of humic acid with nitrogen fertilizers in soil was noticed to be promising technique in increasing yield and quality of spinach.