COMPARATIVE STUDY OF SOIL SEED STOCK AT Hevea brasiliensis PLANTATION AND SWAMPY SOIL OF RIVER ANYA AT UMUDIKE, NIGERIA

Seeds stocked in swampy soil and Hevea brasiliensis plantation soil at Umudike were assessed by enumerating the seeds that germinated from soil monoliths collected from the sites at different months. On the 15 day of each month, four soil monoliths, each 50 x 25 x 10 cm were taken from the swampy soil of which two soil monoliths were taken from the depth 0 -10 cm and the remaining two from 10 - 20 cm depth. The same method was used in collecting four soil monoliths from Hevea brasiliensis plantation from November, 2007 to February, 2008. The effect of light and depth were investigated on the seeds stocked in the soil for 16 weeks. From soil monoliths collected from the swampy soil, a total of 18 species comprising 2489 (97%) individuals germinated from soil monoliths taken from 0-10cm depth and kept in open. Whereas a total of 14 species comprising 116 (3%) individual seeds germinated from soil monoliths taken from Hevea brasiliensis plantation at the same depth. From 10-20 cm depth in open, a total of 12 species comprising 928 (98%) individual seeds germinated from the soil monoliths collected from swampy soil while 10 species comprising 20 (2%) individual seeds germinated from soil monoliths collected from Hevea brasiliensis plantation. Depth has significant effect (p < 0.05) on the number of seeds germinated from the soil monoliths in the shade, a total of seven species comprising 151 (77%) individual seeds germinated from swampy soil while nine species comprising 45 (23%) individual seeds germinated from Hevea brasiliensis from the 0-10 cm. From 10-20 cm depth, six species comprising 113 (88%) individual seeds germinated from swampy soil while four species comprising 15 (12%) individuals germinated from Hevea brasiliensis plantation. Seed germination started within the first seven days of collection and germination stopped after seventy days. There is significant difference (p < 0.05) between the number of seeds germinated at the swampy soil and the number germinated per month from the soil monoliths collected from the Hevea brasiliensis plantation. The more number of seeds germination from soil depth in the open is due to unfiltered red wavelength radiation that reached the soil monolith. The more number of seeds germination from the swampy soil is due to annual seed production of the grasses, sedges and ferns. Neither pioneer nor climax tree species seeds germinated from the swampy soil but four pioneer species seeds Harungana madagascariensis; Macaranga barteri; Uvarea chamae and Hevea brasiliensis germinated from the soil monoliths collected from the Hevea brasiliensis plantation. It is recommended that climax economic tree species such as Khaya ivorensis and Entandrophragma spp should be introduced, as they were absent both in the swampy soil and Hevea brasiliensis plantation. It is recommended that germination of seeds and planting of desirable emergent tree seedlings/stumps should be done by trained foresters to achieve the functions of the forest especially in carbon sink and climate change.