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Selection of chemicals for the modification of Nigerian Ubalaka clay toward formulating a new water-based drilling fluid is very essential. This study investigated the use of NaOH, NaHCO3, KOH and NaCO3 for the modification of Ubakala clay to improve its suitability for water-based drilling fluid. The treated clay was characterized for particle size distribution, crystallinity, morphology, elemental composition and functional group using particle size analyzer, XRD, SEM, XRF and FTIR, respectively. Locally sourced additives namely: cassava starch (CS), breadfruit starch (BFS), bush mango seed (BMS) and corn fiber (CF), were used to improve the rheological properties of developed drilling fluid. Rheological properties were determined as viscosities obtained at 300 and 600 rpm using rheometer. Clay characterization reveal that the quality of montmorillonite was improved via treatment with NaHCO3. Rheological properties were significantly improved by the addition of the four additives. The highest viscosity recorded was 22.30 cp at 600 rpm. However, further optimization of additives is required to achieve properties comparable to those of API standard. [ABSTRACT FROM AUTHOR]

Field trials were conducted to evaluate the effect of foliar spray of aqueous extracts ofTithonia diversifoliaorOcimum gratissimumon Cercospora leaf spot (CLS) and Alternaria leaf blight (ALB) diseases of sesame intercropped with maize. Spraying regime was at 2 weeks interval from 3 weeks after planting (WAP) until 12 WAP. Extracts ofT. diversifoliaorO. gratissimumreduced the incidence and severity of both diseases. CLS incidence and severity as well as defoliation was significantly (p < 0.05) reduced below what obtained in the unsprayed intercrop. ALB lesion size was significantly (p < 0.05) reduced byT. diversifoliaextract at 8.0% (w/v) from 154.7 mm2(sole crop) or 13.4 mm2(unsprayed intercrop) to 4.9 mm2(sprayed intercrop).T. diversifoliaextract at 8.0% (w/v) enhanced higher values of grain yield/plant and incidence of normal seeds, and lower incidence of fungal infection of seeds than in the unsprayed intercrop. [ABSTRACT FROM AUTHOR]

A field study was conducted in Abeokuta, Nigeria, to investigate the effect of different population densities of sesame intercropped with maize, in a single alternate row (1:1) arrangement on the incidence and severity of foliar diseases of sesame during the early and late cropping seasons of 2006 and 2007, respectively. The experiment comprised four treatments, namely sesame planted at 266,666, 177,777 and 133,333 plants/ha intercropped with maize (53,000 plants/ha) and sole sesame at 266,666 plants/ha. Sesame at 133,333 plants/ha + maize showed a lower incidence of Cercospora leaf spot (CLS) and Alternaria leaf blight (ALB) disease and also produced a higher grain yield than the other treatments. The incidence of normal or discolored seeds was not influenced by sesame population density. Significant negative correlations existed between foliar disease incidence and proportion of normal or white/cream colored seeds. Foliar disease incidence was negatively correlated with incidence of abnormal or discolored seeds. Intercropping did not influence maize agronomic characteristics and grain yields. [ABSTRACT FROM AUTHOR]

This paper describes the current status of vegetation and determines the trace element concentration, of plant species and soil in the Ilesa goldfields of Southwestern Nigeria. The results show that there is a drastic reduction in the vegetal cover in the area as a result of mining activities. There is also an appreciable level of contamination of soil and plant species of the mined sites compared with unmined areas. For instance, the Pb content in cassava and oil palm grown on the mined sites are much higher than the FAO/WHO guideline. The results of this study underscore the need for close monitoring of mining operations in Southwestern Nigeria. [ABSTRACT FROM AUTHOR]