STIMULATION OF TOP AND ROOT GROWTH OF LEUCAENA WITH FARM MANURE IN THE MID-ALTITUDE AGRO-ECOLOGICAL ZONE OF NORTH-WEST CAMEROON

Abstract

Leucaena (Leucaena leucocephala) is most preferred by development workers for agroforestry in the mid-altitude (600–1600 m) agro-ecological zone of North-West Cameroon because its seeds are common and inexpensive. This study was prompted by farmers' reluctance to accept leucaena for agroforestry because its early growth is poor on acid infertile soils prevalent in the area. Leucaena was planted using four-month-old potted plants and, from four months after planting, the shrub was cut five times in 20 months at 120 day intervals. Manuring improved leucaena's growth and biomass at sites with acid and non-acid soil alike. Total biomass responded linearly (R²=0.97) to manure rates at the acid and infertile site and curvilinearly (R²=0.95) at the non-acid site. Total leafy biomass from the first cut and subsequent prunings was highest at 12 months after planting. Manuring increased rooting depth and this contributed to the plant's observed ability to cope with moisture stress during the dry season. The economics of manure use for tree establishment on acid infertile soils for agroforestry systems needs further study.