Evaluation of Soil Physicochemical Properties, Soil Seed Bank and Species Density of Five Plant Communities in Awka Anambra State

The research study investigated the physicochemical properties of the soil in five different locations around Nnamdi Azikiwe University Awka campus for their above ground and seed bank status with regards to their germination rate and species density. The study areas were located at Cattle grazed field at gariki Amansea, abandoned farmland near Chisco Transportation and Engineering workshop, frequently mowed lawn at Unizik e-library, a Savanna woodland behind the banking plaza Unizik and tropical lowland forest at Botanical garden Unizik. The seed bank investigation was conducted from September 2016 to March, 2017. Analysis of variance was used to test significant differences between seed bank densities among experimental plots at different soil horizons. The soil physiochemical parameters among the experimental plots were also analyzed by one-way analysis of variance. Significant differences were tested at P= 0.05 at 95% confidence intervals. Results revealed the highest value for above ground species was found in tropical lowland forest (53.67±6.11) while the lowest was in cattle grazed field (8.00±0.82). Meanwhile the highest value for seed bank was in the frequently mowed lawn Unizik e-library (93.00±18.00) and the lowest was in the forest (6.50±4.95). The comparison of the two groups using T-test revealed that there was a significant difference between the above ground and seed bank values of the tropical lowland forest P=0.003 and also between the above ground and seed bank values of the frequently moved lawn, Unzik e-library P=0.001. More so, the Savanna above ground values and seed bank species value were not significant at P=0.006, as well as cattle grazed field (8.00 ± 0.82) and (50.00± 19.31) at P=0.006. Also, the Savanna plot comparison of above ground (44.50±3.54) and the seed bank (14.00±5.20) revealed significant differences between the two groups at P=0.006. Electrical conductivity was highest in the cattle grazed field (40.00+1.08) and the highest pH value was found in the Unizik e-library (6.19+0.22). Sorensen’s coefficient index revealed the highest similarity between above ground and seed bank species occurred in the cattle-grazed field followed by the frequently mowed lawn Unizik e-library (0.196), then the abandoned farmland (0.074), the Savanna (0.060) and the forest (0.025) respectively. Since the similarity is measured between 0 and 1, it means therefore that there is a weak similarity (0.276) between above ground vegetation and the seed bank in the cattle grazed field while the frequently mowed lawn (0.196) above ground similarity with seed bank was very weak. There is no similarity (0.025) between the above ground vegetation and the seed bank in the tropical forest. This seed bank investigation showed that the number of plant species in the seed bank does not reflect the total number of species in the above ground and the soil properties have an impact on the species density of the areas.