A field experiment was carried out to evaluate the effect of the application of poultry manure and wood ash on the growth and grain yield of maize (Zea mays L.). The poultry manure was applied two weeks prior to planting to allow for proper decomposition. Wood ash was applied a day before planting. There were three treatments in all including the control and the treatments were arranged in a randomized complete block design (RCBD) with three replicates. Plant height and leaf area were taken at three weeks after planting to nine weeks after planting with an interval of two weeks. The grain yield was taken at eleven weeks after planting and was dried, weighed and recorded. The results showed that poultry manure significantly increased plant height (192.0 cm) and grain yield (4.83 t/ha) but has no significant effect on the number of leaves and leaf area with 12cm and 3403.6cm2 respectively. The values of plant height and leaf area of the control were relatively high compared with other treatments. This can be attributed to the availability of Nitrogen in the soil. The wood ash was found to give the lowest values for nitrogen as well as vegetative growth of maize, this could be attributed to the fact that nitrogen tends to volatilize when in contact with alkaline mediums and consequently affect vegetative growth of maize.

Soil microbes are important in various processes that lead to soil fertility, nutrient availability and plant nutrition. These soil microbial organisms are themselves affected by the environment where they occur. Microbes could either be aerobic or anaerobic depending on their oxygen requirements. Oxidation-reduction reaction is a common reaction in anoxic environments and microbes tend to respond to it in different ways. This study therefore sets out to investigate the effect of oxidation-reduction potentials of the soil on activities of soil microorganisms. Results from this study show that highly reduced soils favors bacteria population more than fungi. It was concluded that the survival of fungi is best supported under oxidized and moderately reduced soils, but their existence can be negatively affected when soils become highly reduced. Bacteria that are aerobic thrive best under oxidized and moderately reduced soil. In these conditions, the highest microbial respiration in the soil was also measured.

In a bid to evaluate the effect of selected organic residues and inorganic on the performance of okra (Abelmoschus esculentus), a concurrent experiment was conducted using Gliricidia sepium and Aspilla africana as the source of organic residue while N: P: K and Urea were used as the sources of inorganic fertilizers. The materials were applied solely and in combinations to give a total of nine (9) treatments. The land area used was 28m by 11m partition into 9 plots and replicated three times to give a total of 27 experimental units. The experiment was laid out in a randomized Complete Black Design (RCBD). Okra variety lady finger was planted at a spacing of 60cm by 45cm at a rate of three seeds per hole which was later thinned to one plant per stand. The treatments were applied two weeks after planting. Ten plants were tagged to determine the growth and yield parameters. Data collected were subjected to Analysis of Variance (ANOVA) using SPSS 16.00 version and mean separation was done using Duncan Multiple Range Test (DMRT). It was discovered that treatments containing a combination of N:P:K, urea and gliricidia sepium(T9), gave the best in terms of growth parameter and yield on site 1 while on site 2 a combination of NPK, urea and Aspilia africana (T8) gave the best. This shows the okra responds well to applications of organic residues together with inorganic fertilizers.

A field experiment was conducted to determine the effect of split application of nitrogen fertilizer on soil properties and maize yield. Two sites at Apatapiti layout, South gate of the Federal University of Technology Akure were used as the experimental sites. The experiment was designed in a randomized-complete-block design arrangement with three replications. The treatments consisted of urea applied at four levels of split application (0kgha-1, 60kgha-1 basal application, 30kgha-1 basal application+ 30kgha-1 applied at 15 days after planting, 30kgha-1basal application + 20kgha-1applied at 15 days after planting + 10kgha-1applied at 30 days after planting). The plot size was 2 m x 2 m with 1 m space between plots and blocks. Maize (Zea mays L. var. TZB-SR) was planted at 75 cm by 25 cm spacing and 10 were sampled per unit for yield parameters. Split application of urea (30kgha-1basal application + 20kgha-1applied at 15 days after planting + 10kgha-1applied at 30 days after planting) significantly (p>0.05) increased N content of the soil. There was no significant (p>0.05) difference with regard to other nutrients. Soil pH was significantly (p>0.05) reduced as a result of urea application in all treatments. Split urea fertilizer application retained a considerable amount of nitrogen in soil even after the harvest of maize. Exchangeable cations were not significantly different from one another as well as CEC. Split application of urea (30kgha-1basal application + 20kgha-1applied at 15 days after planting + 10kgha-1applied at 30 days after planting) gave the highest grain yield of maize for both sites. Also, plant biomass of both split application were better than the basal application and control.

Investigating the nutrient composition in soil textural constituent as influenced by land use is a necessity towards a good soil conservative and management measure. In view of this, a laboratory experiment was conducted; soil samples were collected from different locations within and outside the Federal University of Technology, Akure and analyzed for basic chemical elements. The soil sampling was based on land use and six different soil samples were collected at a depth of 0-15cm. These samples included bare soil (BS), waterlogged soil (WS), maize cultivated soil (MS), cassava cultivated soil (CS), cassava-maize intercrop (CM), and mixed cropping of cassava, maize and cowpea (MC). The waterlogged soil was cultivated to rice while the bare soil was not cultivated. The soil samples were air-dried and crushed after which fractionation was carried out using a three-layer sieve to separate the soil particles into different size of 2mm to 0.5mm (Sand), 0.5mm-0.05mm (Silt) and