Growth response of Khaya senegalensis (Desr) A. Juss. seedlings to selected organic manures

The experiment on the growth response of Khaya senegalensis seedlings to selected organic manures was carried out in the Federal College of Forestry, Ibadan. The experiment was arranged in completely randomized design (CRD) with six treatments and seven replicates. Germination was observed for eight days. Assessment of growth parameters commenced two weeks after transplanting and was done weekly for 16 weeks. Total plant height, stem diameter and leaf production were measured. Data were analyzed using ANOVA at 5% probability level. Results showed that T4 (10g of cow dung + 2000g of top soil) had the highest performance in terms of plant height (17.2cm) while T6 (2000g of top soil) had the least height performance (14.9cm). Sources of manures had no significant influence (p<0.05) on the growth of Khaya senegalensis seedlings. The stem diameter growth of the seedlings was not significantly (p<0.05) influenced by the manures. T5 (2.5g of Cow dung + 2.5g of Gliricidia sepium + 2000g of top soil) had the best performance with mean value 0.31mm. T6 (control) had the least performance with 0.26mm. The highest mean leaf count was observed on the seedlings raised on 5g of Gliricidia sepium + 2000g of top soil with 9.5 while seedlings raised on 10 g of Gliricidia sepium + 2000g top soil had the least with 7.9. Manures had no significant effect (p>0.05) on the leaf production of the seedlings. Therefore, more research should be focused on the use of other sources of manures in raising Khaya senegalensis seedlings.Keywords: Growth, Manure, Khaya senegalensis, Seedlings, Gliricidia sepiu

Study on the influence of selected organic manures on the early growth of Senna fistula Linn

The study assessed the manuring potentials of Chromolaena odorata and composted kitchen waste on the growth of Senna fistula seedlings. Germination was observed and assessment of growth parameters commenced two weeks after transplanting and was done weekly for 12 weeks. Seedling height, stem diameter, leaf production and leaf area were measured. Data were analyzed using ANOVA at α0.05. Results showed that T8 (80g of composted kitchen waste + 1.5 kg of top soil) had the highest performance in terms of plant height with 8.08 cm while T4 (80g of Chromolaena odorata leaf powder + 1.5 kg of top soil) had the best performance with mean value 1.44 mm for stem diameter. The highest leaf production was observed on seedlings raised on T8 (80 g of composted kitchen waste + 1.5kg of top soil) with 17.00. However, for leaf area, T8 (80g of composted kitchen waste + 1.5kg of top soil) had the best performance with mean value of 8.00 cm2. The organic manure used for the study had an excellent performance on the growth of Senna fistula seedlings. It is therefore, recommended that composted kitchen waste and Chromoleana odorata leaf powder be adopted for raising seedlings of Senna fistula at the nursery stage.Keywords: Chromoleana odorata, Compost, Growth, Manure, Seedlings, Senna fistul

Changes in soil properties and plant uptake of heavy metals on selected municipal solid waste dump sites in Ile-Ife, Nigeria

In a study to evaluate the contributions of open municipal waste dump to soil heavy metals contamination and the modification of other soil physical and chemical parameters, soil samples were collected at various depths from the vicinity of major dump sites in Ile-Ife (latitudes 7°27' and 7°32', longitudes 4° 22' and 4° 29'), Nigeria. The samples when analyzed, showed that soils in the vicinity of dump sites had significantly higher pH regime compared to the control soil. Soils of the dump sites were found to be enriched with the heavy metals (Zn, Cu and Cd) more than the adjacent soils (control) but were still within tolerable /critical level with the exception of Pb which had a high value of 109.7 ugg-1 above the critical value of 100 ugg-1. There was significant relationship between the soil heavy metal content and plant uptake. Transfer factor (TF) expressed as the ratio of the heavy metal concentration in plants to that of soil varied significantly amongst the dump sites and also amongst the species of the heavy metals. The ten years old dump sites recorded the highest TF value ranging from 0.29 for Zn to 4.05 for Pb. The study therefore showed that changes in physico-chemical characteristics at dump sites could be attributed to interactions of different soil properties rather a single factor.Key words: Heavy metal contamination, seasonal changes, soil pH, soil texture, specific adsorption mechanism, transfer factor, food chain

Assessment of heavy metal concentration in soil and leaves of tree species around a scrap metal recycling factory in Ile-Ife, Osun State, Nigeria

The gaseous emissions from scrap metal recycling factory could cause pollution to the environment if the concentrations are substantial and not properly controlled. This study determined the concentration of some heavy metals (Iron, Copper, Lead and Cadmium) in the leaves of selected tree species and soils around the scrap metal recycling factory in Ile-Ife, Osun state, Nigeria. The heavy metals were analysed, using the Buck Atomic Absorption Spectrophotometer. Samples for analysis were taken from the leaves and soil underneath Newbouldia laevis, Trema orientalis, Tectona grandis, Alstonia boonei, Bridelia micrantha and Senna siamea, trees. The results showed that the mean concentration of Pb and Fe (mg/kg) in the soil underneath these tree species were greater in the dry season than the wet season except in the soil underneath Alstonia boonei that showed no relative change in Pb concentration. The Pb content in the leaves of all the tree species was higher in the wet season relative to dry season, with Tectona grandis having the highest Pb concentration (90.2 mg/kg) in the wet season. However, the concentration of Fe in both wet and dry season was greater than the concentration of other heavy metals analysed in all the tree species. The soil under Tectona grandis was observed to accumulate more Cu (19.3 mg/kg) in the dry season than the other tree species. The study revealed increase in accumulation of heavy metals in the soil during the dry season and the leaves of the studied tree species during the wet season. Tree species whose heavy metal content exceeded permissible levels should be encouraged around metal polluted sites due to their high tolerance for heavy metal concentration.Keywords: Concentration, heavy metals, wet and dry season, recycling factory, tree specie

Arbuscular mycorrhiza contribution to the growth performance and heavy metal uptake of Helianthus annuus LINN in pot culture

A greenhouse experiment was conducted to assess the arbuscular mycorrhiza contribution to the growth performance and heavy metals (Cd and Pb) uptake of Helianthus annuus L. from polluted soils. Cadmium sulfate (CdSO4.8H2O) and lead acetate ((CH3COO)2Pb.3H2O) were applied at the concentrations: Cd- 0,20,40,60,80 mg kg-1 and Pb-0,250,500,750,1000 mg kg-1 in 90 plastic pots filled with 5 kg of topsoil each. Propagules of Glomus mosseae (GM) and Glomus intraradices (GI) at 25 g per pot were applied. Non-inoculated pots served as controls. Each treatment was replicated thrice in completely randomized design. Data were analysed using ANOVA and descriptive statistics. Results showed that arbuscular mycorrhiza (AM) fungi significantly (p ≤ 0.05) influenced the number of leaves, plant height and stem girth of sunflower plants only at 80 mg Cd kg-1 concentration. Highest values of 0.11 mg Cd kg-1 and 0.29 mg Pb kg-1 were obtained with GI in the dry shoot of Helianthus annuus while 0.05 mg Cd kg-1 and 0.23 mg Pb kg-1 were remediated with GM application. Least values of Cd and Pb were removed when no AM was applied. GM and GI fungi enhanced the growth of Helianthus annuus and the uptake of Cd and Pb; but GI performed better. Also, a significant (p < 0.05) reduction of AM fungi colonization percentage was obtained with increase in Cd and Pb concentrations.Key words: Glomus mosseae, Glomus intraradices, Helianthus annuus, phytoremediation, polluted soil

The role of Vesiculararbuscular mycorrhizal (VAM) fungi in alley cropping

Alley cropping trials were conducted on different parts (top, middle and base) of a sloping land to compare the effects of inoculation with vesicular-arbuscular mycorrhizal (VAM) fungi on Senna siamea, Gliricidia sepium and Leucaena leucocephala and cassava (Manihot esculenta Crantz) intercrop on an Alfisol in subhumid southwestern Nigeria. The above ground biomass yield of hedgerow trees one year after establishment was higher at the base than at the top of the slope, bur was not influenced by VAM inoculation at the top of base of the slope. At the middle of the slope, VAM inoculation significantly increased leaf biomass of the hedgerows without influencing their stem biomass. The root yield of alley-cropped cassava at the top and middle of the slope was not affected by VAM Inoculation. Inoculation significantly increased the P and N uptake of the hedgerows in all treatments, and fresh tuber yield of cassava only at the base of the slope

Response of some tropical nitrogenfixing woody legumes to drought and inoculation with mycorrhiza

This paper reports on a study of the influence ofdrought and inoculation with mycorrhiza on dry-matter production, nutrient uptake and water relations of Acacia auriculiformis, Albizia lebheck. Gliricidia sepium and Leucaena leucocephala in a sterile soil. Inoculation with L. leucocephala roots containing vesicular-arbuscular mycorrhizal (VAM) fungi (Glomus and Acaulospora spp.) resulted in infection of 25-68% in regularly watered plants. Drought stress reduced infection by 8-49%. In general, VAM plants survived better, and had more dry matter and nutrients and a larger leaf area, than uninoculated plants. For A. auriculiformis. however, the VAM inoculant reduced leaf area, plant dry weight and nitrogen content, although it increased phosphorus uptake. Inoculation ofA . auriculiformis with the ectomycorrhizal fungus Boletus suillus resulted in higher nutrient uptake than in non-mycorrhizal and VAM plants. Drought stress tended to reduce plant growth as well as phosphorus and nitrogen uptake. With the exception of A. auriculiformis, nutrient content in drought-stressed VAM plants was either greater than or comparable with the nutrient content of unstressed non-mycorrhizal plants

Assessment of health risks from potassium bromate and trace metals in bread consumption in Ado Ekiti, Southwest, Nigeria

Introduction: Bread, a staple food consumed by a large portion of the population worldwide, including Nigeria, has emerged as one of the most popular quick meal options. The excessive intake of potassium bromate and trace metals in bread has been identified as detrimental to human health due to its heightened propensity to induce cancer in human. Objective: The current study assessed the exposure to potassium bromate (KBrO3) and trace metals through bread consumption, as well as the associated risks to dietary habits among Ado Ekiti, Southwest Nigeria residents. Bread varieties commonly consumed in Ado Ekiti were randomly chosen from local bakeries. These bread samples were then analyzed in the laboratory using an Atomic Absorption Spectrophotometer to determine the levels of trace metals, including lead (Pb), manganese (Mn), nickel (Ni), chromium (Cr), zinc (Zn), cadmium (Cd), and cobalt (Co), as well as potassium bromate concentrations. Results: The findings revealed that cobalt (Co) had the highest mean concentration (29.35±3.59 mg.kg−1), whereas lead (Pb) exhibited the lowest mean concentration (0.06±0.02 mg.kg−1). The sequence of trace metal levels was Co > Cd > Zn > Ni > Mn > Cr > Pb. All trace metal concentrations exceeded the standards set by FAO/WHO. Regarding potassium bromate content, it ranged from 0.01 mg.kg−1 to 0.06 mg.kg−1, surpassing the maximum permissible limits of 0.02 mg.kg−1 set by the Food and Drug Administration.Although the chronic hazard quotient among adults and children was low, the hazard ratio ranged from 11 to 9 among adults and from 14 to 9 among children, suggesting the potential for carcinogenic effects with repeated consumption. Based on the hazard ratios, the estimated chances of developing cancer from daily consumption of bread samples were approximately 14 in 1,000,000, 86 in 1,000,000, 71 in 1,000,000, and 40 in 1,000,000, respectively, for the adult population, and about 20 in 1,000,000, 11 in 1,000,000, 90 in 1,000,000, and 56 in 1,000,000 for the children population. Conclusion: The study showed that trace metals Pb, Mn, Ni, Cr, Zn, Cd and Co concentrations were higher than the FAO/WHO permissible limits. The concentration of potassium bromate in all the sorted bread samples exceeded the maximum acceptable limits except one. Though chronic hazard quotient among adults and children was low, the hazard ratio among the adult and children population was high, signifying possible cancer risks when continually consumed. These findings underscore the importance of stringent oversight by Nigerian regulatory authorities over using potassium bromate as an ingredient in bakeries

Effects of ectomycorrhizal and vesculararbuscular mycorrhizal fungi on drought tolerance of four leguminous woody seedlings

Seedlings of Acacia auriculiformis A. Cunn. ex. Benth., Albizia lebbeck (L.) Benth., Gliricidia sepium (Jac.) Walp and Leucaena leucocephala (Lam.) de Wit. were inoculated with an ectomycorrhizal (Boletus suillus (L. ex. Fr.) or indigenous vesicular-arbuscular mycorrhizal (VAM) fungi in a low P soil. The plants were subjected to unstressed (well-watered) and drought-stressed (water-stressed) conditions. In Gliricidia and Leucaena , both mycorrhizal inoculations stimulated greater plant growth, P and N uptake compared to their non-mycorrhizal (NM) plants under both watering regimes. However, in Acacia and Albizia , these parameters were only stimulated by either ectomycorrhiza (Acacia) or VA mycorrhiza (Albizia). Growth reduction occurred as a result of inoculation with the other type of mycorrhiza. This was attributed to competition for carbon between Acacia and VA mycorrhizas and parasitic association between Albizia and ectomycorrhiza. Drought-stressed mycorrhizal and NM Leucaena , and drought-stressed mycorrhizal Acacia tolerated lower xylem pressure potentials and larger water losses than the drought-stressed mycorrhizal and NM Albizia and Gliricidia . These latter plants avoided drought by maintaining higher xylem pressure potentials and leaf relative water content (RWC). All the four leguminous plants were mycorrhizal dependent. The higher the mycorrhizal dependency (MD), the lower the drought tolerance expressed in terms of drought response index (DRI). The DRI may be a useful determinant of MD, as they are inversely related