FORAGE AND SEED YIELDS, MORTALITY AND NUTRITIVE VALUE OF <em>SESBANIA</em> <em>SESBAN</em> UNDER UNIMODAL RAINFALL IN TANZANIA

Abstract

Fifteen Sesbania sesban accessions were assessed for edible forage and seed production, plant survival and fodder nutritive value over a three-year period. Plants were cut at six months to estimate edible yield while seed was harvested for up to eight months from undisturbed growth, and plant survival was assessed from both cut and intact plants at ten months from transplanting. Considerable differences were recorded in all parameters examined.
Edible yields varied from 0.2 to 2.0 t ha^-1 with a major decline in production when rainfall was < 450 mm. Seed production varied from 7 to 483 kg ha^-1 and was least affected by moisture stress. Plant mortality ranged 25-95% (cut) and 28-82% (intact) in 1991, and 28-73% (cut) and 17-68% (intact) in 1993 when rainfall was > 700 mm; and 71-100% ( cut) and 62-96% (intact) when rainfall was <450 mm in 1992. The nutrient contents in the forage ranged as follows: nitrogen 2.2-3.0%, phosphorus 0.15-0.20%, potassium 0.9-1.9%, calcium 1.0-1.4% and magnesium 0.2-0.4% in the dry matter. It was concluded that all nutrients except phosphorus were adequate for ruminant animal production and that inadequate moisture was one of the major factors that limited edible forage production.