Yields and the nutritive value of early harvested common bean (Phaseolusvulgaris L.) crop residues for ruminants

The yields and nutritive value of haulm (stem and leaf) and pod wall (HPW) crop residues of common bean early-harvested atthe green pod fill stage were measured in nine genotypes grown in two dissimilar environments (Boricha and Mandura) inEthiopia. The concentrations of total N, neutral detergent fibre (NDF) and acid detergent fibre (ADF), and the in vitro DMdigestibility (IVDMD), in the HPW fractions (stem, leaf and pod wall) were measured. At Mandura the yields of seed and HPWaveraged 1.03 and 2.26 t/ha, respectively, and varied (p0.001) among genotypes (0.31-1.57 t/ha and 1.19-2.93 t/ha,respectively). However no such differences among genotypes (p0.05) were observed at Boricha. Stem, leaf and pod wallcomprised 52.4, 23.1 and 24.5% of HPW, respectively. The concentrations of N, NDF and ADF, and IVDMD in the HPW, andthe HPW fractions, generally varied (p0.05) among genotypes. The digestible DM (DDM) yields of HPW ranged amonggenotypes from 0.75-1.81 t/ ha at Mandura, and averaged 1.89 t/ha at Boricha. N yield ranged from 35.3-70.3 kg N/ha atBoricha and 18.3-43.4 kg N/ha at Mandura. Since yields of seed were positively correlated with yields of HPW DM, DDM andN, common bean genotypes can be selected concurrently for seed and HPW yields. Uses of high-yielding genotype can doublethe N and DDM yields without reducing seed yield. The N and IVDMD of HPW residue showed that early-harvested commonbean is a high nutritive value feedstuff for ruminants.