ABSTRACT

Contribution of Anacardium occidenta/e (cashew) to site quality was assessed at Isuochi in Umunneochi Local Government Area of Abia State. Three plots of 0.3ha each comprising a 25 -year old Anacardium occidentale plantation, a cassava cultivated farmland with 4 -year history of continuous cropping and a 5 -year old fallow land were used in the study. Parameters determined were types of floral species and their densities and soil physico - chemical characteristics as well as some chemical characteristics of cashew leaf litters. Four sampling sub-plots were delineated on each of the three plots. From the four sub-plots serving as replicates, quadrats of 2mx2m were used in sampling for the parameters. Plant species and their population densities were determined from each quadrat. The chemical characteristics of the cashew leaf litters were also assessed in each sub-plot. The soil chemical characteristics at 0-15cm and 15-30cm soil depth were determined. Counting of plant species and the determination of the soil chemical characteristics were done using a randomized complete block design. A total of 6 species of plants with a mean total density of 49. 75 plant species per 0.3ha occurred in the cashew plantation, with Amorphophallus abyssinicus (30%) and Abrus precatorius (25%) being more abundant. In the cassava plot a total of 12 plant species were identified with a mean total density of 162.75 plant species per 0.3ha.Solanum fulvum with a mean population of 40. 75 (25%) plants was more abundant in this plot. A total of 26 plant species with a mean total density of 683. 75 plant species per 0.3ha were encountered in the fallow plot. Dactyladenia barteri with a mean population of 110.50 (16.2%) plants was more abundant in the fallow plot. The species richness index for A. occidentale plantation, cassava farm and fallow plots were 0.43, 0.47 and 0.50 respectively. Again, results showed that the soil chemical characteristics in the XII cashew were significantly lower than that in the fallow area. N, P, K, OC and OM were highest in both soil layers of the fallow land. Also, Ca, Na and Fe levels decreased in the cashew plot compared to the fallow plot. However, N and K were least in both soil layers of the cassava-cultivated land. The lowest pH values (high acidity) and Ca level were recorded in the cashew plantation in both soil layers. The cashew leaf litter has high content of lignin which retards decomposition of organic materials. This limited the contribution of the vegetation to soil fertility particularly N, p, K, OC, Ca, Na and Fe. This may make A. occidentaes not to be suitable for amelioratimg soil with low productivity.