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This study investigated morphological variation and biomass accumulation that occurred in Sida acuta and Chromolaena odorata plants grown in lead polluted soil under organic fertilizer amendment. The study was carried out in the screen house at the Biological Gardens of the Obafemi Awolowo University, Ile-Ife, Osun State. The experiment was a factorial combination of one heavy metal (Pb) at five levels of concentration (0, 200, 400, 800 and 1,000 mg/kg) in a completely randomized design, and were replicated three times for each of the two plants and two levels (0 g/kg and 9.4 g/kg) of organic fertilizer (OBD-Plus). Each pot was filled with 5 kg of air-dried and sieved soil and placed on a plastic tray for the collection of excess water. Two weeks after planting, seedlings of uniform height were transplanted from the nursery to experimental pots at the rate of one seedling per pot and grown for 10 weeks. The growth parameters of the plants were biomonitored for 7 weeks. After 10 weeks of treatment, the plants were harvested and dried to calculate the biomass accumulation. The two plant species performed better under fertilizer application than without it. For each of the plant species the growth parameters decreased as the levels of Pb concentration increased. Furthermore, the plants' biomass decreased significantly (p<0.05) as the levels of Pb concentration increased. The organic fertilizer helped to improve the plants' performance in lead-polluted soil. 相似文献
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Abel Ojo Talabi 《Arabian Journal of Geosciences》2018,11(21):681
Volumes of water in shallow wells of Ekiti State Southwestern Nigeria was estimated during the rainy and dry seasons of 2017 to categorize the area into different groundwater potential zones and to scrutinize it for groundwater sustainability and development. Locations of the wells were measured using etrex 12 Channel GPS while dip meter was employed for the water levels and depths of wells. The volume of water in a well was estimated employing V = πr2h (r and h are radius and water column of well, respectively). The wells in the area have low water storage (av. 6.91m3 and 2.70m3 in rainy and dry seasons, respectively). The study area had sufficient quantity of water in the rainy season to meet domestic, agricultural, and industrial requirements as deficiency was met from rainfall replenishment. Groundwater potential evaluation revealed that majority of the study area fell into very poor to poor water categories. Groundwater sustainability and development in the study area is a herculean task due to uncoordinated sitting of wells, low storage of water in the aquifers, and erratic occurrence of the groundwater. Hygiene education should be intensified in the area to forestall the risks post by the principal elements of fecal oral disease transmission. 相似文献
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The paper examined the concept of development in line with the role of geospatial technology applications in governance and geospatial management in Nigeria. It also evaluates the previous efforts made by successive governments in managing governance process through geospatial technology initiatives using Lagos State as a proof-of-concept. It empirically demonstrates the role of monitoring spatial development initiatives using Landsat multi-dates satellite images 1985, 1990, 1995, 2000, 5005, 2010 and 2016 and Geographic Information System technique. The paper then identified, mapped and examined the settlement growth of Lagos using Ikorodu Division as an empirical proof-of-concept. The study reveals a geometric increase in uncoordinated human activities resulting from sporadic spatial development (builtup area) from 27.67 sq km (7.7%) in 1985–313.02 sq km (87.3%) spatial coverage in 2016. Based on the regression line, the study reveals a strong correlation between increasing settlement development and time. Low level of community involvement and lack of sense of ownership of development project initiatives in developing a local “vision” and strategy are identified as a problem. The paper re-emphasized that sustaining democratic processes as well as the fight against poverty will be won or lost mostly in the rural and less in the urban areas. The rural area is home to about 70% of the world’s poor due to lack or inadequate government services and basic amenities. The study suggest that making the future better for the yet unborn requires appreciable fundamental dataset, technologies, human resources and reliable government structures. 相似文献
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The propagation of seismic waves through Earth models with slightly random lateral and vertical inhomogeneities superimposed on one composed of layers with vertical velocity gradients was investigated. The maximum deviation of velocity from a mean value at a given depth and a correlation distance derived from a two-dimensional smoothing filter were two parameters used to vary the amplitude and size of the velocity anomalies. The resulting models show short discontinuous reflectors scattered about at various depths throughout the model, and are thus in agreement with many deep seismic reflection experiments. On the other hand numerical experiments using ray-tracing techniques showed that the effect of the lateral and vertical velocity anomalies is to scatter the energy, and break up the continuous travel-time lines from vertical gradient models into travel-time segments with different slopes similar to those observed in many long range seismic refraction experiments, and to those resulting from layering effects in the media. Many of the numerical experiments which modelled the random crust produced a Pg segment and a P* segment with an apparent Conrad discontinuity at a depth of 10–20 km, this apparent depth being related to the correlation distance.When a seismic wave propagates through a heterogeneous Earth the amount of its energy which is converted into scattered energy will be a function of the inhomogeneous characteristics of the medium through which it has passed. If a ray passes through a homogeneous Earth the energy arriving at an array station should be relatively coherent whereas if the ray encounters lateral and vertical inhomogeneities its energy will be incoherent and much more complex. A series of coherency measurements done on array recordings of earthquakes at various distances showed that large lateral and vertical variations in complexity exist for different ray paths through the Earth with the region below the 650 km discontinuity in the mantle tending to be much simpler than the region just below the lithosphere. 相似文献
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Studies on turbulent diffusion processes and evaluation of diffusivity values from hydrodynamic observations in Corpus Christi Bay 总被引：1，自引：0，他引：1
The physical process of dispersion which can be attributed to turbulence (turbulent diffusion) or shear (shear-augmented diffusion) within the flow field is very important as it ultimately governs the distribution of constituents of interest within the environment. A series of diffusion experiments were conducted in Corpus Christi Bay, TX with the purpose of characterizing turbulent diffusion through dispersion coefficients or turbulent diffusivity, Ki (i=x, y, z) dependent on the degree of randomness or turbulence intensity, I.Measured with a boat-mounted acoustic doppler current profiler (ADCP), the Eulerian velocity time-series of fluid particles in random motion, ui was used in the evaluation of the Eulerian time-scale of turbulence, TE based on the velocity correlation function, RE with TE being related to the Lagrangian time-scale TL through a scaling parameter, β(=TL/TE). Surface currents were obtained with high frequency (HF) Radar equipment deployed over the study area from which the horizontal velocity gradients were determined.Within the spatial scale of the experiment (1000 m), the observed low horizontal gradients (10−4 s−1) allowed for the generation of velocity time-series from an ADCP mounted on a moving platform. A numerical scheme for evaluating turbulent diffusivity values was developed on the basis of Eulerian current measurements and calibrated through the statistics of an evolving dye patch for the scaling parameter β which in this scheme was found to be in the range 1–3. 相似文献
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Soyeun Kim Godwin Uyi Ojo Rukhe Zehra Zaidi Raymond L. Bryant 《Singapore journal of tropical geography》2012,33(1):34-48
For all its vitality political ecology often appears to be a project in which work by Anglo‐Americans in particular, if it is not privileged, certainly predominates. This trend reflects wider language and intellectual tendencies in human geography and the social sciences that distort the development of the field by downplaying or obscuring the contributions of many non‐Anglo‐Americans and by naturalizing Anglo‐American assumptions at the heart of research. The latter in turn determine what constitutes ‘good’ work – even as there is no single definition of political ecology. Arguing against this tendency, this paper draws on postcolonial thinking to emphasize the need to reassess and reorient the field as ‘other’ political ecologies are feasible and desirable. 相似文献
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A set of outcrop samples from the Lokoja and Patti Formations of the southern Bida Basin (Nigeria) was examined for grain size distribution, sedimentary and hydraulic characteristics. Most of the samples are well-sorted with an uniformity coefficient (U) ranging between 1.3 and 6.3. The mean effective grain diameter (d10) is in the order of 0.11 mm, the mean value of d90 was determined as 0.66 mm (both geometric mean) and the median grain size (d50) as 0.23 mm. Based on these values, the sedimentary sequence can be described as ‘fine to medium sized sand’, having minor amounts of either silt, or coarse sand and some gravel. The total porosity of the samples was determined by laboratory methods to be in the range of 9–29%. The hydraulic conductivity (K) was determined according to Hazen.and Beyer, and by Shepherd's formula, the last resulting in a geometric mean of 3.3 m d−1 or 3.3 darcy. The results are used to estimate local groundwater potential. The entire pore space (potential groundwater reservoir) for the area under study is estimated to be in the order of 290–430 km3. Because of higher hydraulic conductivities, it is recommended that the Lokoja Formation is concentrated on as a target for groundwater exploration. 相似文献
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A.K.TULOKHONOV 《资源与生态学报(英文版)》2011,(3):280-282
The considerable part of the Northern Asia is occupied with the steppe and forest-steppe landscapes stretched by a wide strip from Caspian Sea to mountains of Big Khingan.Archeologists claim, that from here on the Bering Bridge after a glacial age ancestors of American Indian tribes have left to the North America. In the Baikal Lake basin we find settlements of ancient Huns, subdued the Eastern and Western Europe in the beginning of last millennium. 相似文献