Scaling up production of traditional green leafy vegetables in Kenya: Perspectives on water and nitrogen management

Traditional green leafy vegetables are promising alternative vegetable crops consumed in Kenya and other African countries. The crops whose consumption is on the increase include vegetable amaranth (Amaranthus spp.), African nightshades (Solanum spp.) and spiderplant (Cleome/Gynandropsis gynandra). They are popular in the Kenyan retail markets and key supermarket chains as surveys have shown. This offers the urban dwellers access to these vegetables on one hand, while offering a reliable market for growers on the other hand. They are also potential export crops as the consumption continues to widen in most parts of Asia too. For a long time these crops have not been integrated into mainstream agriculture. Consequently, they have received little attention in terms of research and development, resulting in many gaps in information. Production continues to be on small-scales, with the farmers being the major custodians of the genetic materials and production technologies. With the current upsurge of interest in traditional vegetables, there is need to raise production to meet the increasing demand. Some agronomic studies aiming to develop optimal cultivation practices for improved yield and nutritive quality of these crops have been reported. More research work on these crops is necessary to facilitate increased production. In this paper, research into the water and nitrogen use in traditional leafy vegetables is reviewed. The paper aims to show the current status of research, major gaps in information in an effort to scale up production of these crops to meet the increasing demand.