Yield and quality of fennel (Foeniculum vulgare Mill.) in relation to basal and foliar application of nitrogen and phosphorus

Abstract

A split‐plot field trial was conducted to study the effect of foliar application of 0 kg/ha (control), 20 kg N/ha, 2 kg P/ha or 20 kg N + 2 kg P/ha at two basal levels, viz., 90 kg N + 40 kg P/ha (optimal dose) and 60 kg N + 27 kg P/ha (sub‐optimal dose). Each group received 50 kg K/ha, which was applied uniformly on the yield and quality of fennel. Spray was applied at the flowering stage, 120 days after sowing.

The optimal basal dose gave better results than did the sub‐optimal one. Spray of 20 kg N + 2 kg P/ha proved optimum. This spray proved more effective at sub‐optimal than at optimal basal dose. The percentage of anethole (but not of fenchone) in the essential oil was significantly higher in plants grown with the sub‐optimal basal dose. Foliar application of N, P and N + P, on the other hand, decreased the anethole content of oil and increased that of fenchone significantly. Hence, foliar feeding may be recommended if the oil is required for perfumery and confectionary industries.