Influence of applied nitrogen on growth and tissue nutrient concentration in the medicinal plant Ajowain (Trachyspermum ammi)

Abstract

Growth performance and nutrient accumulation in Ajowain [Trachyspermum ammi (L.) Sprague] under varying levels of nitrogen were examined in a field experiment. Sixty-three-day-old plants were supplied with varying levels of N, i.e. 0, 30, 60, and 90 kg N/ha soil. Maximum biomass was recorded at 60 kg N/ha, whereas maximum seed yield was recorded at 60 and 90 kg N/ha. Shoot and root P and N increased with an increase in external N levels applied, reaching a maximum at 90 kg N/ha. However, tissue K concentration remained almost unchanged at varying soil N levels. Although accumulation of N and P in both shoots and roots of Ajowain increased consistently with an increase in soil N, this pattern of increase in the levels of 3 nutrients in plant tissues had a negative association with the growth of the crop, particularly at the higher N level (90 kg N/ha) where seed yield per plant was almost equal to that at 60 kg N/ha.