Effect of Nitrogen Sources and Storage Method on Nitrate Content of Kale (Brassica Oleracea Var.Acephala Leaves

Abstract

A study was conducted at Kabete Field Station, University of Nairobi, Kenya, to investigate the possible effects of nitrogen sources and storage on nitrate-nitrogen content in Kale leaves. Leaves from ‘plants that were top-dressed with calcium ammonium nitrate (CAN) accumulated more nitrate-nitrogen than those from those that were top-dressed with sulphate of ammonia (SA). Storage of leaves reduced nitrate-nitrogen concentration in the leaves, but the reduction was not accompanied with NO,-N accumulation. Storing leaves with petioles immersed in water reduced the nitrate-nitrogen concentration than storing the leaves on the shelf. Even though the refrigerated leaves may remain B9 fresh for a longer period than six days, no reduction of NOs-N during the refrigeration 33 period Occurred. The petioles prior to preparation of Kale leaves as human feed may reduce NOs-N concentration in the leaves.