Management and Productivity of the Systems
Generally, the tree legumes take at least 1 year to establish. Leucaena hedgerows establish much faster but raising seedlings in a nursery can be expensive. Most farmers use direct seeding, which is easier, but the trees take longer to establish. Gliricidia hedgerows are easily established from stem cuttings. Napier grass is planted together with the trees but is cut frequently to avoid shading of the tree seedlings.
After establishment, the tree hedgerows are cut to a stump height of
50 cm and the subsequent harvests are made at the same time as the harvesting of Napier grass. The grass is harvested when it attains a height of 1 m and should be cut at 10 cm above the ground. Clitoria is also harvested at the time of harvesting Napier grass. Farmers are advised to fertilize Napier grass using inorganic N at the rate of 75 kg ha-1. The recommended rate of slurry application is 55 t ha-1 and it should be buried
10 cm between Napier grass rows to reduce loss of nitrogen by volatilization (Mureithi et al. 1996a).
Studies at the RRC have indicated that forage production systems
combining Napier grass and legumes yield more total DM than Napier grass grown alone (Table 3). Napier grass is tolerant of frequent cutting, while Leucaena is a prolific leaf producer in fertile soil. However, the performance of the intercropped forages suffers, especially during stress conditions. The arrival of the psyllid pest (Heteropsylla cubana Crawford) in the region in 1992 (Reynolds and Bimbuzi 1993) severely affected the productivity of Leucaena but it has now stabilized, probably because of the establishment of natural enemies. The productivity of the various forage production systems in farmers’ fields has not been well studied. However, careful management can maintain high biomass yield of both Napier grass and legumes over several years.