A decomposition study was carried out on the leaf litters of Leucaena leucocaephala to determine the rate of decomposition of its leaves with respect to its placement on above or below the ground levels in L. leucocaephala plantations of the Federal University of Agriculture, Abeokuta, Nigeria. In the study, leaf litter were randomly handpicked from the forest floor, of this, 40 g each were weighed into thirty (30) litter bags of 2 mm mesh size in which 15 were randomly placed on the forest floor (above-ground) and the remaining 15 were buried in the soil between 5-10 cm depth (below-ground). Data were analysed using descriptive statistical techniques such as percentage, while inferential statistics (simple linear regression) was used to determine relationships between various nutrient elements and days of decomposition (DOD). We noted that the percentage of mass loss of leaf litter increased with time in days after deposit and was higher (29.93%, 32.43 % and 33.25%, 41.65%) at 80 to 100 days of placement above- and below-ground, respectively. Moreover, the exchangeable basic cations and chemical compositions of litters were not consistent with respect to DOD. Regression analysis of nitrogen (N) and organic carbon (OC) showed that these elements significantly contributed to the high (86 %) overall decomposition of litter (p < 0.05, p < 0.01) below-ground level. It is, therefore, concluded that decomposition of leaf litters occur faster below ground than above ground within the forest plantation.
Improvement of Parkia seedling growth on plant height (PH) using seed dormancy breaking technologies in different soil media was investigated at nursery unit of Department for Forestry and Wildlife Management, Federal University Dutsin-Ma. Completely Randomized Design (CRD) with four replicates was the design used. The data were analyzed using Analysis of Variance (ANOVA) while the means were separated using Fishers’ Least Significant Difference (F-LSD; P≤ 0.05). Emergence of seeds was observed to commence four days after sowing (DAS) in mechanically scarified seeds (MS). The top soil added with mycorrhiza at 120 g (M120+) had significantly higher value (24.01) on PH at 10 weeks after sowing (WAS) in the main effect. In the interactive effect, seeds soaked in 98 % concentrated tetraoxosulphate (V1) (H2SO4) for 2 and 4 minutes (A2 and A4) and sowed in sterilized top soil (SS) and non-sterilized (NS) had significantly higher values (16.70 and 16.25) and (27.60 and 28.25) on PH at 4 and 12 WAS respectively. Seeds soaked in H2SO4 for 6 minutes (A6) and sowed in M120+ had higher value (15.60) on PH at 4 WAS. MS in M60+, hot water (HW) at 80 ºC and 100 ºC for 10 and 5 minutes had higher effect (16.52 and 16.48) on PH at 4 WAS. MS in HW at 60 ºC for 15 minutes and HW 80 ºC in M60+ was significant on PH (26.80, 27.85 and 29.00) at 12 WAS. HW 60 ºC in SS had higher effect (15.95) on PH at 4 WAS. In conclusion, mechanically scarified seeds, seeds soaked in H2SO4 acid for 2-6 minutes and in hot water between 60 ºC to 100 ºC for at most 15 minutes break Parkia dormancy and grow rapidly in ectomycorrhiza soil.
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