Nodulation, chlorophyll content and nitrogen yield of two woody legumes at Ile-Ife, Southwestern Nigeria
Two field studies were conducted at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife, Nigeria between 2000 and 2002 to compare the growth, nodulation, chlorophyll content and nitrogen accumulation of Leucaena leucocephala (Lam) de Wit cv. 28 and Gliricidia sepium (Jacq.) Walp cv. ILG50 at the early stages of growth (2-16 months after planting) (MAP) without inputs. A randomized complete block design with three replications and the species as treatments was used. Between 8 and 16 MAP, the biomass yield of G. sepium (5.10 kg/plant) was higher than that of L. leucocephala (1.35 kg/plant). The number of nodules produced by G. sepium (96.0/plant) was higher than in L. leucocephala (44.0/plant). Fresh weight of nodules of G. sepium (41.30 g/plant) was higher than in L. leucocephala (18.9 g/plant). Similarly, dry weight of G.sepium (18.5 g/plant) was greater than that of L.leucocephala (7.6g/plant) throughout the period of study. Nodulation index of G. sepium (5.5%) was higher than that of L. leucocephala (3.7%) at 4 and 8 MAP. At 12 and 16 MAP, leaf total chlorophyll content of G. sepium was 6.12 µM/g and significantly (P<0.05) higher than 4.12 µM/g produced by L. leucocephala. However, chlorophyll stability index of L. leucocephala (94.5%) was significantly higher (P<0.05) than that of G. sepium (69.7%). At final sampling (16 MAP), G. sepium partitioned 48.3 and 51.7% of its total nitrogen content to below ground and above ground parts respectively. In contrast, the values were 35.3 and 64.7% respectively for L. leucocephala. Significantly (p<0.05) higher nitrogen accumulation occurred in G. sepium (54.20 kg/plant) than in L. leucocephala (42.80 kg/plant) at 16 MAP. It is concluded from the study that G.sepium has a higher potential than L. leucocephala as a hedge species in terms of nodulation, chlorophyll content and nitrogen yield under no-external input field conditions.
Keywords: Chloropyhll; G. sepium; L. leucocephala; nodulation index
Moor Journal of Agricultural Research Vol. 7 (1&2) 2006 pp. 76-84