Abstract

The influence of mycorrhizal fungi in uptake of heavy metals, pollution response index and yield of sunflower in degraded soils were investigated. It was a greenhouse experiment with 2 arbuscular mycorrhizae (Glomus mosseae, Glomus intraradices) and a non-inoculation that served as control. The treatments were replicated 3 times in a completely randomized design. Each of the treatment consisted of 30 pots and each pot was filled with 5 kg by weight of dried top soil. Solutions of lead acetate and cadmium sulphate at variable levels of: 0, 250, 500, 750, 1000 mg kg-1 and 0, 20, 40, 60, 80 mg kg-1 respectively were used to pollute the soils. Increase in pollution-stressed conditions significantly (P<0.05) reduced the infection of sunflower roots, and the uptake of Pb and Cd in the dry root of sunflower was also significantly (P<0.05) reduced. Also, arbuscular mycorrhizae enhanced the root infection of sunflower, increased the pollution tolerance and consequently increased the yield of sunflower

The effects of marble mining activities on the properties of soils of Igbeti marble area, Oke-Ogun, Southwestern Nigeria were investigated. Sample plots of 10 x 10 m 2 were established at 150 m intervals from the factory site up to a distance of 600 m and with a sample plot at 10 km to serve as control in four cardinal directions. A total of 84 composite soil samples from 21 established plots were taken for soil physico-chemical properties. No plot falls under agricultural crops. The results show that there is drastic deterioration in the quality of soil as a result of mining activities. There was increase in total porosity and decrease in bulk density of the soil as you move away from the mining site. The soil pH changed greatly from 5.90 in the control site to 8.20 in highly polluted soils. Soil organic matter, total nitrogen and available phosphorus decreased with increase in dust particulate from the mining sites. Except for Ca 2+ and Mg 2+ that decreased with distance from the mining site, Na + and K + increased slightly. The availability of the extractable micronutrients (Fe 2+ , Mn 2+ , Cu 2+ and Zn 2+) increased as the soil acidity increased, though Cu 2+ availability dropped slightly at control site. It is concluded that there is the need for close monitoring of marble mining activities in Nigeria as deposit of marble particulates may result to soil nutrients' imbalance and hence poor soil health especially in areas polluted with marble particulates.

No abstract

The study investigated the effects of poultry manure compost (PMC) on the growth performance and yield of maize (Zea mays L.) when cultivated on spent engine oil (SEO) contaminated soil with a view to assessing its nutritional composition. The experiment consisted of three SEO treatments (0%, 1% and 2% w/w) with six levels (0, 2, 4, 6, 8 and 10 t ha-1) of PMC applications. Each treatment was replicated thrice and arranged in a 3 × 6 × 3 factorial completely randomized design to give a total of 54 pots. At full physiological maturity, maize grains were harvested and threshed manually for analysis. As the bioavailability of metals increased with increasing PMC, their uptake by maize plants was enhanced. The soil amended with 10 t ha-1 and contaminated with 1% SEO recorded the highest uptake rates of 1.761 × 10-2, 2.345 × 10-2 and 4.285 × 10-2 day-1 for Fe, Cu and Pb respectively. Also, the significantly (P<0.05) highest yield of maize (5.8 t ha-1) and the highest nutritional values of crude protein (11.27 g 100 g-1) and crude fibre (2.71 g 100 g-1) were obtained with zero SEO soil contamination at 10 t ha-1 PMC applications. There was evidence of yield and nutritional quality reduction of maize when cultivated on SEO contaminated soils with or without poultry compost fertilization