African Journal of Soil Science

African Journal of Soil Science ISSN 2375-088X Vol. 7 (3), pp. 001-008, March, 2019. © International Scholars Journals

Full Length Research Paper

Enhancement of steel sheet-piling quay walls using grouted anchors

Mohamed El-Naggar

Department of Civil Engineering, Faculty of Engineering, Alexandria University, Alexandria, Egypt. E-mail: [email protected].

Accepted 18 January, 2019

Abstract

Steel sheet-pilings are one of the most common types of quay walls used in the construction of ports and harbors facilities, especially for berths of small crafts which have small dimensions and capacity. Due to the growing market of marine traffic around the world, an increasing number of these berths are required to be upgraded to meet the requirements of permanently growing dimensions and capacity of vessels. Several methods can be used to increase the load-carrying capacity of steel sheet-piling walls. The use of additional anchored tie rods grouted into the backfill soil and arranged along the exposed wall height is one of the most appropriate solutions adopted for rehabilitation and upgrading of the existing quay wall. An extensive parametric study through the finite element program, PLAXIS, version 8.2 was carried out to investigate the enhancement of using grouted anchors technique on the load response of sheet-piling quay wall. The influence of sheet-pile wall geometry, grout-ties area, inclination and location, length of grout, dredging depth and backfill soil angle of internal friction to enhance this type of walls are analyzed and the results are presented.

Key words: anchor, grouting-ties, harbor, marine, quay wall, sheet pile, retaining wall.

African Journal of Soil Science ISSN 2375-088X Vol. 7 (3), pp. 001-006, March, 2019. © International Scholars Journals

Full Length Research Paper

The potential of four non traditional legumes in suppressing the population of nematodes in two Ghanaian soils

K. Osei¹*, J. O. Fening², S. R. Gowen³ and A. Jama³

¹Crops Research Institute, Box 3785, Kumasi, Ghana.

²Soil Research Institute, Academy Post Office, PMB, Kwadaso Kunmsi, Ghana.

³University of Reading, School of Agriculture, Policy and Development, Box 237, Earley Gate, RG6 6AR, Reading, UK.

Accepted 24 January, 2019

Abstract

Most African farmers could not afford the purchase of pesticides to control crop pest, alternatives such as the use of phytochemicals are most useful. For best results, sound recommendations are needed on the use of different antagonistic plants in controlling pest. In Ghana few reliable data are available on the potential of antagonistic plants to control nematode population. A field trial was conducted in the forest and forest savanna transitional zones of Ghana to evaluate the potential of four leguminous crops in suppressing nematodes population. Mucuna pruriens, Crotalaria spectabilis and C. retusa were antagonistic but Phaseolus vulgaris was a favourable host to the pest. M. pruriens did not gall and no egg masses found on roots. C. spectabilis and C. retusa recorded insignificant galling indices of 2.6 and 1.8 respectively. However, P. vulgaris was significantly affected by Meloidogyne incognita as expressed by the significantly higher gall and egg mass indices. In addition, nodulation was greatly reduced in P. vulgaris. Consequently, significant higher population of nematodes (an average of 600 J2/g^-1root) was recovered from P. vulgaris whilst lower population (an average of 50 J2/g ^-1root) was recovered from M. pruriens. The growth and yield of okra following M. pruriens resulted in a significant 48% yield increase over the control and P. vulgaris treatments. M. pruriens recorded 31 and 38% yield increase over C. spectabilis and C. retusa respectively.

Key words: Agricultural production, antagonistic plants, legumes, Meloidogyne incognita.

African Journal of Soil Science ISSN 2375-088X Vol. 7 (3), pp. 001-008, March, 2019. © International Scholars Journals

Full Length Research Paper

Optimization of key parameters for chromium (VI) removal from aqueous solutions using activated charcoal

M. Seyf-laye Alfa-Sika, Fei Liu* and Honghan Chen

Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083, China.

Accepted 21 January, 2019

Abstract

Commercial activated charcoal was investigated for removal of Cr(VI) from aqueous solutions. The effects of altering the initial Cr(VI) concentration, pH, contact time and amount of activated charcoal were studied. Maximum adsorption of Cr(VI) was achieved between pH 1 - 3 and after a contact time of 120 min. The percentage of Cr(VI) removed decreased from 99.99 - 90.83 % when the initial Cr(VI) concentration was increased from 0.05 - 0.5 mg ml^-1 at pH 2 and 26 ± 2°C. Various kinetic models such as pseudo first-order, pseudo second-order and Elovich models were used to evaluate the mechanism of Cr(VI) adsorption on activated charcoal. The Cr(VI) removal process was found to be governed by second-order kinetics and the rate constant of the adsorption (k₂) was 0.1800 g kg^-1 min^-1 for an initial Cr(VI) concentration of 0.1 mg ml^-1. The adsorption of Cr(VI) was evaluated using Langmuir, Freundlich, and Temkin isotherms and their constants were determined. The maximum adsorption capacity obtained using the Langmuir isotherm model was 45.24 g kg^-1 at pH 2.

Key words: Key parameters, activated charcoal, adsorption, aqueous solutions, Cr(VI).

African Journal of Soil Science ISSN 2375-088X Vol. 7 (3), pp. 001-006, March, 2019. © International Scholars Journals

Full Length Research Paper

The utilization of wood ash as manure to reduce the use of mineral fertilizer for improved performance of maize (Zea mays L.) as measured in the chlorophyll content and grain yield

F. O. Adekayode¹* and M. R. Olojugba²

¹Department of Crop, Soil and Pest Management, Federal University of Technology, Akure, Ondo State, Nigeria.

²Department of Soil Science and Management, Joseph Ayo Babalola University, Ikeji Arakeji, Osun State, Nigeria.

Accepted 10 December, 2018

Abstract

The increasingly high cost of mineral fertilizers and a preferred economic disposal of wood ash had necessitated a research in the use of wood ash to reduce the rate of fertilizer application for maize production. The comparative effects of wood ash and NPK 15-15-15 on maize were investigated in Akure (7⁰15’N, 5⁰15’E), Nigeria in 2008. The four treatments investigated were 4 t/ha wood ash, 300 kg/ha NPK 15-15-15, 200 kg/ha NPK 15-15-15 plus 2t/ha wood ash mixture and a control plot without manure; while the land preparation was ploughed and harrowed once. Downy mildew resistant (DMR) open pollinated maize variety was planted at 60 × 30 cm in a randomized complete block experiment replicated four times, and the manure was applied in a ring at 10 cm from the maize plant. Pre- treatment soil analysis that entailed taking soil samples before the application of manure was carried out. Two maize crops were investigated and the means of data were computed for comparisons across treatments. The total leaf area per plant, leaf area index and the chlorophyll content were correlated to the grain yield. The profitable response was computed to confirm the economic viability. The chlorophyll content and the grain yield were significantly high in 200kg/ha NPK 15-15-15 + 2t/ha wood ash mixture and in 300 kg/ha NPK 15-15-15 compared to other treatments. Corresponding higher net revenues were also obtained which confirmed a mixture of wood ash and inorganic mineral fertilizers to be a suitable agronomic practice for profitable maize production.

Key words: Wood ash, mineral fertilizers, chlorophyll content, maize grain yield.

African Journal of Soil Science ISSN 2375-088X Vol. 7 (3), pp. 001-006, March, 2019. © International Scholars Journals

Full Length Research Paper

Soil management strategies for rubber cultivation in an undulating topography of Northern Cross River State

J. R. Orimoloye*, I. K. Ugwa and S. O. Idoko

Rubber Research Institute of Nigeria, P. M. B. 1049, Benin City, Edo State, Nigeria.

Accepted 10 January, 2019

Abstract

This study was conducted to evaluate the soil fertility status of an undulating topography of a young rubber plantation located at Ikot- Ukpora, Biase Local Government Area of Cross Rivers State and its implication for rubber cultivation. The result showed that the soils of the area ranged from loamy sand to sandy loam on the surface overlying a slightly heavier textured sub-soil ranging from sandy loam to sandy clay loam. Most areas of the soils studied have gravely layers less than 100 cm from the surface leading to a matured plantation in the area to adopt a survival mechanism of curly tap root geometry with preponderance of extensive lateral root system that compensates for the tap root. The soils were slightly acidic and low in most essential nutrients. Total N, P and ECEC were generally low. Fertilizer recommendations were made for the different stages of rubber growth while other management strategies were suggested aimed at reducing organic matter losses and minimizing soil erosion as well as control of termite infestation.

Key words: Rubber, soil fertility, soil properties, Nigeria.

African Journal of Soil Science ISSN 2375-088X Vol. 7 (2), pp. 001-009, February, 2019. © International Scholars Journals

Full Length Research Paper

Reducing compaction effort and incorporating air permeability in Proctor testing for design of urban green spaces on cohesive soils

A. M. Ibrahim¹, N. Persaud²*, R. W. Zobel³ and A. Hass⁴

¹Soils and Water Department, Faculty of Agriculture, El-Fayoum University, Fayoum, Postal Code 63514, Egypt.

²Crop and Soil Environmental Sciences Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0404, USA.

³USDA/ARS Appalachian Farming Systems Research Center, 1224 Airport Road, Beaver, West Virginia, USA.

⁴West Virginia State University, Gus R. Douglass Institute, P. O. Box 1000, Institute, WV 25112-1000, USA.

Accepted 16 December, 2018

Abstract

It is well established that compaction negatively affects agronomic productivity, that air permeability is a sensitive measure of the degree of soil compaction and therefore a good indicator of soil productivity impairment from compaction. Cohesive soils in urban settings are often heavily compacted by the common engineering practice to compact sub-grades of urban construction sites to 95% or more of the optimum density obtained in standardized Proctor tests. The objective of this study was to determine to what extent reducing compaction effort would increase the air permeability of Proctor test specimens. Quantifying this relationship would permit more appropriate Proctor test specifications for the design of urban green spaces on cohesive soils. We designed a portable transient flow apparatus for rapidly measuring air permeability and used it to measure air permeability on Proctor test specimens of three cohesive sub-grade soil materials covering a range of USDA textures (loam, silt loam and silty clay) and Proctor compaction characteristics. We compacted test specimens at their Proctor optimum water content using efforts ranging from 100 to 25% (the lowest practicable value) of that used in the standardized Proctor test. Results confirmed that compaction severely reduces air permeability of the test specimens and indicated that the common practice of compaction to 95% or more of the optimum Proctor density is probably not appropriate for construction of urban green spaces. Reducing compaction effort from 100 to 25% of the standardized Proctor test value increased air permeability 30, 89 and 42 times respectively for the loam, silt loam and silty clay test specimens. More extensive studies are needed to correlate measured air permeability of Proctor test specimens to agronomic productivity of urban green spaces.

Key words: Urban soils, air permeameter, modified Proctor test.