Botanical features of Albizia niopoides

The genus Albizia belongs in the tribe Ingae along with the closely related genera Enterolobium, Pithecellobium and Samanea. Generic relationships have yet to be fully resolved in the tribe. Twelve species of Albizia are known to occur in Central America and Mexico. Confusion over the identity of A. niopoides arose through the use of the name A. caribeae to be synonymous with A. niopoides which was described earlier, based on botanical collections from S. America. The correct name for this widely distributed species is now A. niopoides.

A. niopoides is also sometimes confused with Enterolobium cyclocarpum due to the similarity in tree form and foliar characteristics. The bark is smooth, pale golden yellow, and powdery in texture on mature trees. The leaves are bipinnate, with 5-10 pairs of pinnae per leaf, 30-50 pairs of leaflets per pinnae, and small leaflets with a glossy upper surface. The flowers are arranged in small pedunculate heads and are pale cream and inconspicuous. The pods are small, straw yellow when ripe, flat, and dehiscent along both pod margins. The small yellow-brown seeds often remain attached by the persistent funicle to the pod valves after pod dehiscence and are carried by wind over moderate distances.

Natural distribution

The natural range of Albizia niopoides is from S. E. Mexico in the states of Oaxaca, Chaipas, and the Yucatan Peninsula, through Central America and the southern West Indies to South America as far south as Argentina, Paraguay, Peru, and southern Brazil in the state of Para. The species occurs mainly in seasonally dry tropical forest with rainfall in the range of 500-1200 mm and a pronounced dry season of 4-7 months. It is a lowland species ranging from sea level to 1000 m elevation (Rico Arce 1993).

Objectives

The study has the following objectives: 1. To investigate the potential nutrient contribution of Albizia niopoides to an alley cropping system. 2. To critically assess the species rate of nodule production and the nutrient quality of its biomass.

Materials and methods

In an attempt to meet the above objectives, the following experiments have been carried out:

(1) Factors affecting germination of A. niopoides seeds. Under this study we considered the effect of pretreatments of cold or warm water and sowing depth on germination.

(2) Effects of Rhizobium inoculation on the seedling growth of A. niopoides. The aim is to assess the influence of different quantities of Rhizobium strain on the growth and development of A. niopoides.

Soil collected from IITA was sieved and 2.9 kg was filled into 7-inch pots, which were appropriately labeled according to treatments. Potted seedlings (about 6 weeks old) raised in the nursery were planted into them and left for two weeks for proper establishment. The pots were later inoculated and arranged in a randomized complete block design with three applications. They were watered with 20 ml distilled water daily.

The plants were assessed for height, collar diameter, leaf number, and leaf area. Nodulation and biomass production were determined after 5 months.

Isolation of the strain. Selected nodules of A. niopoides seedlings potted on 24 February 1992 and 28 August 1991 were surfaced sterilized and rhizobia strains in these nodules were isolated. Inoculation was performed one week after establishment of the seedlings. The treatments were (1) 1ml of Rhizobium inoculation; (2) 5 ml of Rhizobium inoculation; (3) 10 ml of Rhizobium inoculation and (4) control.