Growth, yield and nitrate accumulation of irrigated carrot and okra in response to nitrogen fertilization

摘要

A randomized block experiment conducted on Sultanpur silt loam evaluated the N effects on growth and nitrate accumulation of okra (Hibiscus esculents L. cv. Sabz pari) and carrot (Daucus carota L. cv. T29). Treatments consisted of a control, 100, 150 and 200 kg N ha-1. Significantly higher yields of carrot and okra were recorded at 150 kg N ha-1. Nitrate concentration in both increased ( 35 to 200%) with increasing N. An excessive nitrate accumulation in both was recorded at 200 kg N ha-1. Okra had 1.7 times higher nitrate accumulation than carrot. Early season okra had a significantly higher nitrate (~10%) than late season. Gross income and profitable return responded quadratically with increasing N. Results suggest that N fertilization of carrot and okra at 150 kg N ha-1is optimum for economical yields with less accumulation of nitrate in vegetables.