Nigerian Soils Research Articles

Diversity, molecular phylogenetics, and antibiotic biosynthetic potential of endophytic Actinobacteria isolated from medicinal plants in Nigeria.

Actinobacteria that are found in nature have enormous promise for the growth of the pharmaceutical sector. There is a scarce report on the antimicrobial activities of endophytic Actinobacteria from Nigeria. As a result, this study evaluated the Actinobacteria isolated from Nigerian medicinal plants in terms of their biodiversity, phylogenetics, and ability to produce antimicrobial compounds. Following accepted practices, Actinobacteria were isolated from the surface-sterilized plant parts. They were identified using 16S rRNA sequencing, microscopic, and morphological methods. The cell-free broth of Actinobacteria isolates was subjected to antimicrobial assay by agar well diffusion. Molecular evolutionary and genetic analysis (MEGA) version X was used for phylogenetic analysis, and the interactive tree of life (iTOL) version 6.0 was used to view the neighbour-joining method-drawn tree. A total of 13 Actinobacteria were recovered, belonging to three genera including 10 strains of Streptomyces, 2 strains of Saccharomonospora, and only 1 strain of Saccharopolyspora. They showed inhibitory activity against several bacterial pathogens. The phylogenetic tree generated from the sequences showed that our isolates are divergent and distinct from other closely related strains on the database. Further, optimization of the antibiotic production by selected Saccharomonospora sp. PNSac2 was conducted. It showed that the optimal conditions were the ISP2 medium (1-2% w/v salt) adjusted to pH of 8 at 30-32℃ for 12-14days. In conclusion, endophytic Actinobacteria dwelling in Nigerian soils could be a promising source of new antibiotics. Future research is warranted because more genomic analysis and characterization of their metabolites could lead to the development of new antibacterial medicines.

Effects of combined nitrogen-nutrient sources on lowland rice straw yield (a potential dairy feed) in a derived savannah ecology

Low rice yields in farmers’ fields arise from inadequate nitrogen in most Nigerian soils. Fertilizer use has increased, particularly with the implementation of COVID-19. Straw is a by-product of cereal plants, consisting of dry stalks left over after the grain and chaff. It accounts for cereal crop yields, such as barley, oats, rice, rye, and wheat. The effects of greenhouse gas emissions from burning straw on the climate have been a cause for alarm. As a result, this study in Abeokuta, Southwest Nigeria, investigated the effects of six levels of integrated nutrient sources on NERICA L-34 and ARICA 3 through the analysis of variance in straw yield data. The experiment used a split-plot design, complete block randomization, and treatment arrangements in triplicate. At harvest, ARICA 3 produced significantly more straw (p = 0.05) (14.04 t/ha) than NERICA L-34 (10.44 t/ha) by combining 50 kg N/ha (NPK 15:15:15) with 50 kg N/ha (poultry manure) (10.12 t/ha). The study improved the straw yield (11.4 t ha−1) of ARICA 3 and NERICA L-34 by 50 kg N/ha (NPK 15-15-15) and 50 kg Nha−1 (poultry manure); thus, this straw could be used as dairy feed.

Correlating the succession of microbial communities from Nigerian soils to petroleum biodegradation

Whilst biodegradation of different hydrocarbon components has been widely demonstrated to occur by specialist oil-degrading bacteria, less is known about the impact on microbial communities as a function of oil composition by comparing the biodegradation of chemically complex fuels to synthetic products. The objectives of this study were (i) to assess the biodegradation capacity and succession of microbial communities isolated from Nigerian soils in media with crude oil or synthetic oil as sole sources of carbon and energy, and (ii) to assess the temporal variability of the microbial community size. Community profiling was done using 16 S rRNA gene amplicon sequencing (Illumina), and oil profiling using gas chromatography. The biodegradation of natural and synthetic oil differed probably due to the content of sulfur that may interfere with the biodegradation of hydrocarbons. Both alkanes and PAHs in the natural oil were biodegraded faster than in the synthetic oil. Variable community responses were observed during the degradation of alkanes and more simple aromatic compounds, but at later phases of growth they became more homogeneous. The degradation capacity and the size of the community from the more-contaminated soil were higher than those from the less-contaminated soil. Six abundant organisms isolated from the cultures were found to biodegrade oil molecules in pure cultures. Ultimately, this knowledge may contribute to a better understanding of how to improve the biodegradation of crude oil by optimizing culturing conditions through inoculation or bioaugmentation of specific bacteria during ex-situ biodegradation such as biodigesters or landfarming.

Vertical and lateral movements of nitrate, phosphate and sulphate in soils around manure dumpsites and the potential environmental implications.

Monitoring and quantification of nutrient movement in soils could help farmers and policy makers to formulate effective nutrient loss reduction strategies and waste management. The study was conducted to monitor and quantify vertical and lateral movements of nitrate-nitrogen (NO3-N), phosphate (PO4) and sulphate-sulphur (SO4-S) in soils around manure dumpsites in Abeokuta, southwest Nigeria. The dumpsites investigated include a flush-type poultry litter, poultry litter mixed with beddings of wood shavings and cattle and pig waste open dumpsites. Soils were sampled at depths of 0-20, 20-40, 40-60 and 60-80cm and at distances 2, 4, 6, 8, 10, 20, 40, 60 and 80m away from the dumpsites. Soil samples were analysed for some physical and chemical properties and NO3-N, PO4 and SO4-S contents. Results indicated that there were more nutrients in the soil around the poultry manure slurry dumpsite compared with others while the soil pH increased with increase in soil depth, across dump sites. There was evidence of leaching of salts, and this correlated positively with the soil organic matter content (r = 0.41, p < 0.01). The soils were polluted with NO3-N, PO4 and SO4-S as deep as 80-cm depth; these nutrient amounts were higher than the maximum allowable (40, 15 and 7mgkg-1, respectively) for southwest Nigerian soils. Due to high soil organic matter and for agronomic considerations, the soils are only suitable for cultivation at depths below 40cm and 8m away from the dump sites. There was significant pollution of the soils with nitrate, phosphate and sulphate, within 80m distance from the dump site. This has serious implications for ground water recharges and shallow well sunk around these areas. There is potential risk of NO3-N, PO4 and SO4-S consumption through such water sources.

Enhanced L-lysine Production by UV-irradiated and S-2-aminoethyl-L-cysteine Resistant Mutants Derived from Bacillus species Using Agricultural Products as Carbon and Nitrogen Sources

L-Lysine is essential for human and animal nutrition and may be added to food and feed materials to improve the protein quality. It is utilized in human medicine, in cosmetics and in the pharmaceutical industry, particularly in the formulation of diets with balanced amino acid concentration and in amino acid infusions. Enhanced L-lysine production by UV irradiated and S-2-aminoethyl-L-cysteine resistant (AECR) mutants derived from Bacillus species, using agricultural products as carbon and nitrogen sources was studied. The L-lysine producing bacteria had already been isolated from Nigerian soil. They were purified and identified as B. subtilis PR13, B. subtilis PR9 and B. pumilus SS16, using cultural and biochemical characteristics. UV irradiated mutants were obtained by exposing the parent strains which include B. subtilis PR13, B. subtilis PR9 and B. pumilus SS16, to UV light while, AECR mutants were derived by exposing the parent strains to various concentrations of AEC. The mutants were screened for L-lysine production by cultivating in fermentation media. The results obtained showed that, UV mutants PRMU-8 and PRMU-14 derived from Bacillus subtilis PR13 accumulated higher lysine yield of 2.47 and 2.55 mg/ml compared to the wild type. Also, UV mutant MUPR-4 derived from Bacillus subtilis PR9 recorded a higher lysine yield of 1.77 mg/ml while, enhanced lysine yields of 1.96 and 2.34 mg/ml were observed in UV mutants SSMU-4 and SSMU-9 respectively. AECR mutant PRT-2 derived from Bacillus subtilis PR13, accumulated higher lysine yield of 2.35 mg/ml compared to the wild type. Enhanced lysine production of 1.47 and 1.32 mg/ml was observed in mutants ART-5 and ART-8 derived from B. subtilis PR9 while, mutant SRT-4 derived from B. pumilus SS16 recorded enhanced lysine accumulation of 2.18 mg/ml. The results obtained in the study showed that L-lysine production by some UV irradiated and AECR mutants was enhanced.

The Influence of Vitamins, Antibiotics and Growth Stimulators on L-lysine Production by Bacillus subtilis Using Agricultural Products as Carbon and Nitrogen Sources

L-Lysine is one of the 9 amino acids which are essential for human and animal nutrition. It is a basic building block of all proteins and cannot be synthesized biologically in the body. The influence of vitamins, antibiotics and growth stimulators on L-lysine production by Bacillus subtilis using agricultural products as carbon and nitrogen sources was examined. The L-lysine producing bacteria had already been isolated from Nigerian soil. They were purified and Identified as B. subtilis PR13 and B. subtilis PR9, using cultural and biochemical characteristics. The of influence of vitamins, antibiotics and growth stimulators on L-lysine production by Bacillus subtilis PR13 and 9 was evaluated in 100 ml flasks containing 20 ml fermentation media (FM1 and FM2). The results obtained showed that, an enhanced lysine yield of 3.41 and 1.57 mg/ml by Bacillus subtilis PR13 and Bacillus subtilis PR9, was observed in the presence of 1 µg/ml of biotin and 10 µg/ml respectively. The supplementation of 0.04 units/ml of penicillin, enhanced optimum L-lysine yield of 2.38 mg/ml for B. subtilis PR 13 and 1.64 mg/ml for B. subtilis PR9 respectively. The addition of 0.1% w/v peptone and yeast extract, enhanced optimum L-lysine yield of 2.66 mg/ml for B. subtilis PR 13 and 1.72 mg/ml for B. subtilis PR9 respectively. There was a positive correlation between peptone and L-lysine production by B. subtilis PR13 (r= 0.85) and yeast extract and L- lysine production by B. subtilis PR9 (r= 0.54). The results obtained in the study showed that the supplementation of the fermentation media with some vitamins, antibiotics and growth stimulators enhanced the L-lysine yield of B. subtilis PR13 and B. subtilis PR9.

Modelling the deactivation of Escherichia coli in Nigerian soils amended with differently treated manures.

This study aimed to simulate deactivation of E. coli in soils amended with cattle manure after burning, anaerobic digestion, composting or without treatment. The Weibull survival function was used to describe deactivation of E. coli. Parameters for each treatment were determined using E. coli measurements from manure-amended soils and evaluated against measurements at different application rates. A statistically significant correlation and high coincidence between the simulated and measured values was obtained. The simulations revealed that although anaerobic digestion or burning of cattle manure effectively reduced the E. coli loads to background levels, burning retained very little nitrogen, so the ash residue was ineffective as an organic fertiliser. Anaerobic digestion was most effective at reducing E. coli levels while retaining a high proportion of N in the bioslurry residue, but the persistence of E. coli was higher than in compost. The results from this study suggest that the safest method for production of organic fertiliser would involve anaerobic digestion to reduce E. coli followed by composting to reduce its persistence.

Why are some suicide terror attacks more newsworthy than others?

ABSTRACT Given their deeply deviant nature, suicide terror attacks are highly newsworthy events and in theory, should attract high levels of media coverage. However, this is not the case and some suicide bombings tend to be covered more extensively than others. Through a detailed case study of Boko Haram, this research delineates the conditions under which suicide attacks are more likely to be covered across national, regional and international media outlets. The analysis relied on a dataset of 473 suicide attacks carried out by Boko Haram since 2011. Drawing on a news media distortion analysis, this study finds multiple attributes of suicide terrorism can entice heightened levels of reporting. Suicide attacks entailing higher fatalities, female perpetrators and civilian targets all lead to greater media attention while ambiguity in terms of perpetrator gender identity significantly diminishes coverage. Moreover, all of these factors are robust across national, regional and international media outlets, though the effect of gender is strongest for international media sources. Suicide attacks on Nigerian soil are generally more likely to be covered compared to attacks elsewhere in West Africa where Boko Haram is also active and this effect is especially strong for international media coverage.

The influence of surfactants and bivalent metals on L-lysine production by Bacillus subtilis using agricultural products as carbon and nitrogen sources

The influence of surfactants and bivalent metal ions on L-lysine production by Bacillus subtilis using agricultural products as carbon and Nitrogen sources was studied. The L-lysine producing bacteria had already been isolated from Nigerian soil. They were purified and identified as B. subtilis PR13 and B. subtilis PR9, using cultural, biochemical and molecular characteristics. Optimization of some parameters which included, surfactants and bivalent metal on L-lysine production by B. subtilis was carried out. The L-lysine was produced in 100 ml flasks containing fermentation media FM1 and FM2. The findings revealed that, enhanced lysine yield of 3.30 mg/ml and 1.46 mg/ml by B. subtilis PR13 and B. subtilis PR9, was observed in the presence of 0.1 µg/ml of stearic acid and 0.1% v/v Tween 80 respectively. The supplementation of 5 µg/ml of CuSO4 and 1 µg/ml of NiCl2, enhanced optimum L-lysine yield of 3.18 mg/ml for B. subtilis PR 13 and 1.51 mg/ml for B. subtilis PR9 respectively. The results obtained in the study illustrated that the optimization of process parameters could increase the L-lysine yield by B. subtilis PR13 and B. subtilis PR9.

The Influence of Amino Acids and Trace Elements on L-lysine Production by Bacillus subtilis Using Agricultural Products as Carbon and Nitrogen Sources

The influence of amino acids and trace elements on L-lysine production by Bacillus subtilis using agricultural products as carbon and nitrogen sources was studied. The L-lysine producing bacteria had already been isolated from Nigerian soil. They were purified and identified as B. subtilis PR13 and B. subtilis PR9, using cultural, biochemical and molecular characteristics. Optimization of some parameters which included amino acids and trace elements on L-lysine production by Bacillus species was carried out. The L-lysine was produced in 250 ml flasks containing fermentation media (FM1 and FM2). The findings revealed that, enhanced lysine yield of 2.88mg/ml and 1.68 mg/ml by Bacillus subtilis PR13 and Bacillus subtilis PR9, was observed at in the presence of 0.1% (w/v) of glycine and leucine respectively. There was a negative correlation between amino acid and lysine production by the B. subtilis PR 13 (r= -0.74) and PR 9 (-0.55). The supplementation of 0.005 g/l of MgSO4.7H2O and FeSO4.7H2O enhanced optimum L-lysine yield of 2.56 mg/ml for B. subtilis PR 13 and 1.36 mg/ml for B. subtilis PR9. There was a positive correlation between MgSO4.7H2O and lysine production by the B. subtilis PR 13 (r=0.96) and FeSO4.7H2O and lysine production by B. subtilis PR9 (r= 0.94). The results obtained in the study, illustrated that the optimization of process parameters could increase L-lysine yield from agricultural products by B. subtilis PR13 and B. subtilis PR9.

The Influence of Agitation Rates, pH and Calcium Carbonate on L-lysine Production by Bacillus subtilis using Agricultural Products as Carbon and Nitrogen Sources

L-Lysine is an essential amino acid that is required in the diet of humans and animals. It is utilized in human medicine, cosmetics and pharmaceutical industry. ’The influence of agitation rates, pH and calcium carbonate on L-lysine production by Bacillus subtilis using agricultural products as carbon and nitrogen sources was studied. The L-lysine-producing bacteria had already been isolated from Nigerian soil. They were purified and Identified as B. subtilis PR13 and B. subtilis PR9, using cultural, biochemical and molecular characteristics. Optimization of some parameters which included agitation rates, pH values and CaCO3 concentrations, on L-lysine production by the Bacillus species was carried out. The L-lysine was produced in 250 ml flasks containing fermentation media (FM1 and FM2). The findings revealed that, enhanced L-lysine yield of 2.10 and 1.33 mg/ml was observed at agitation rate of 180 rpm for B. subtilis PR13 and PR9 respectively. There was a positive correlation between agitation rates and L- lysine production by B. subtilis PR13 and PR9 (r = 0.96 and 0.83 respectively). The pH of 7.5, stimulated optimum L- lysine yield of 2.27 mg/ml for PR13 and 1.38 mg/ml for PR9. There was a positive correlation between pH values and L-lysine production by B. subtilis PR13 and PR 9 (r = 0.63 and 0.50 respectively). The supplementation of 40g/l of CaCO3, enhanced optimum L-lysine yield of 2.18 mg/ml for B. subtilis PR 13 and 1.30 mg/ml for B. subtilis PR9. There was a positive correlation between varying concentrations of calcium carbonate and L-lysine production by the B. subtilis PR13 (r =0.35), while negative correlation was observed for B. subtilis PR 9 (r = -0.10). The results obtained in the study illustrated that the optimization of process parameters could increase the L-lysine yield from agricultural products by B. subtilis PR13 and B. subtilis PR9.

From Freedom of Expression to Freedom of Speech – the Guarantees under the Nigerian Constitution and the Real Challenges

Right to freedom of expression is one of the globally recognized fundamental rights guaranteed and protected in many international human rights conventions, charters and other international and regional treaties and instruments. In Nigeria, the right has always been given recognision and specifically provided for in all the Nigeria’s constitutions, including the colonial and pre-independence. Even under the constitutional arrangements under the military governments, the said right is given recognition. Under the 1999 Constitution of Federal republic of Nigeria, the said right has also been prescribed for as one of the rights guaranteed for all Nigerians and anybody on the Nigerian soil. Nevertheless, it is one thing to recognize a right and it is completely another to practically implement the guarantees provided for. The Nigerian constitution is said to have given the said right with one hand and takes it away with another hand. This article critically analyses the right to freedom of expression under the Nigerian Constitution 1999 to discover whether or not the constitution as is being alleged, is really speaking from two sides of its mouth.

Growth response and antioxidant enzyme capability of Helianthus annuus L. in lead contaminated soil under organic and urea fertilizer applications

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Indiscriminate dumping of wastes, including heavy metals such as lead (Pb) on Nigerian soils is increasing. &lt;em&gt;Helianthus annuus&lt;/em&gt; has been found to have ability to clean up contaminated soils, but with paucity of information on the effect of Pb stress on the plant’ antioxidant enzymes activities when fertilizers are applied as soil enhancers, hence this study.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;The experiment consisted of four levels (0, 400, 800, 1200 mg Pb kg&lt;sup&gt;-1&lt;/sup&gt;) using [Pb (CH&lt;sub&gt;3&lt;/sub&gt;COO)&lt;sub&gt;2&lt;/sub&gt;.3H&lt;sub&gt;2&lt;/sub&gt;O], three rates (0, 5 and 10 t ha&lt;sup&gt;-1&lt;/sup&gt;) of organic and two rates (0 and 2 t ha&lt;sup&gt;-1&lt;/sup&gt;) of urea fertilizers, and each treatment was replicated thrice to give a total of 72 experimental units in pot culture. Each pot contained 10 kg of sieved topsoil and arranged in a complete randomized design. The &lt;em&gt;H. annuus&lt;/em&gt; seeds were sown, fertilizers were applied and stands of &lt;em&gt;H. annuus&lt;/em&gt; were collected for antioxidant enzymes (SOD, CAT, POX and APX) activities determination in the roots and shoots using standard methods.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Soil&lt;strong&gt; &lt;/strong&gt;pH&lt;strong&gt; &lt;/strong&gt;was slightly acidic and soil texture was loamy sand. Biomass yield of &lt;em&gt;H. annuus &lt;/em&gt;increased with increase in organic fertilizer, but decreased with increase in Pb contamination. There was significant (p&amp;lt;0.05) increase in detoxification responses in the shoots than the roots of &lt;em&gt;H. annuus&lt;/em&gt; against oxidative stress caused by Pb toxicity when&lt;em&gt; &lt;/em&gt;organic fertilizer was applied to soil.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;The study concluded that addition of organic fertilizer increased biomass yield and had superior enhancing detoxification responses on &lt;em&gt;H. annuus&lt;/em&gt; against oxidative stress by Pb toxicity.&lt;/p&gt;

Soil Survey and Land Suitability Evaluation for Sugar Cane Production at Zagga District, Bagudo Local Government Area, Kebbi State, Nigeria

Semi-detail soil survey and land suitability evaluation for sugarcane production was carried out in Zagga, Bagudo LGA of Kebbi State Nigeria at scale of 1:25,000 on 8,000 ha of land. The objectives were to describe the morphological and chemical properties of the soils. The entire study area was classified in to five soil units named as ZG1, ZG2, ZG3, ZG4, and ZG5. Surface soil samples were examined and collected from 0-15cm, 15-30cm depth using soil auger at 200x200m interval. Five soil profile pits were dug, described and soils sampled from bottom up, to minimized contamination by falling debris. Each soil profile pit was described based on horizon thickness, depth, colour of matrix and mottles, consistency, included materials, roots, horizon boundary, vegetation/ land use, slope, depth to water table and drainage status. The soils are slightly acidic (6.30) to moderately acidic (5.60). The total nitrogen, organic carbon, available phosphorus, and basic cations (Ca, Mg, K, Na) were low to moderately low according to guidelines for nutrient rating and interpretation for Nigerian soils. The soils were moderately drained. According to USDA soil taxonomy classification the soils of ZG 1 and ZG 2 were classified as Dystrustepts while ZG 3, ZG 4 and ZG 5 were classified as Haplustepts and correlated with World Reference Based System as Arenosols and Luvisols. ZG1 and ZG2 were named as moderately suitable (S2) while ZG3, ZG4 and ZG5 were marginally suitable (S3) according to the guidelines of land suitability evaluation for sugarcane production.

Soil Phosphorus Fractions, Reaction, and Conductivity in Some Southwestern Nigerian Soils as Affected by Animal Manure Mixtures

ABSTRACT Phosphorus fractions constitute a strong determinant of phosphorus availability in soils and their amount fluctuates with the application of manure and NPK fertilizer. Incubation study, screen house, and field experiments were conducted to evaluate the effects of animal manure mixtures on soil phosphorus fractions, pH, and electrical conductivity (EC) in some southwest Nigerian soils. Surface soil samples (0–20 cm) from four locations and cured animal manures (goat, cattle, and poultry) were collected, dried, and analyzed. Treatments of control (no manure), manure mixtures of cattle-goat, cattle-poultry, poultry-goat, and NPK 15:15:15 at 90 kg P ha−1 were applied to soils. Samples were taken fortnightly and analyzed for pH, EC, and P fractions (Available-P, Labile-P, Aluminum-P[Al-P], and Iron-P[Fe-P], Calcium-P [Ca-P]and Residual-P). Significant (p < .05) increase in pH was observed at the onset of the experiments with subsequent decreases across weeks, a reverse trend was observed for soil EC. The addition of poultry manure complimented the effect of goat manure by increasing Labile-P, Al-P, and Fe-P, Ca-P, Residual-P while cattle-goat manure mixture increased available P. Under the field trial, a significant (p < .05) increase occurred in Labile-P, Ca-P, and Residual-P with the application of poultry-goat manure. While in available-P, Al-P, and Fe-P, poultry manure addition complimented the effect of cattle manure by significantly (p < .05) increasing the P fractions. Poultry manure inclusion is recommended for use in manure mixtures because of its complementary and synergistic effect on other manures.

Fertility Status of Selected Agricultural Soils Along Major Roads in Nasarawa Eggon and Doma Areas of Nasarawa State, North Central, Nigeria

Soil nutrient status determines its crop productivity and provide basis for appropriate soil management. The soil samples which spread across the agricultural farms along major roads in Nasarawa Eggon and Doma areas of Nasarawa State, Nigeria; were analyzed for both physical and chemical properties. Most of the studied Nasarawa Eggon and Doma soils were extremely acidic. Textural class showed high sand content (&gt;80) of the investigated soils, indicating possible high rate of water infiltration in these soils which will lead to their low water holding capacity. The organic carbon (OC) contents in both locations, were rated high as it varied from 1.50 to 1.85 %, whereas total nitrogen (TN) levels ranged from 0.07 to 0.21 % in the studied soils. The levels of available P, Ca, K and Mg were inadequate for satisfactory plant growth, considering their respective critical level established for Nigerian soils. Mineral analysis showed the presence of essential elements such as S, K, Ca, Mg, Fe, Mn, Cu, Ni, Co, Mo and Zn. Beneficial/functional elements such as Ti, V, Rb and Sr, were found in significant quantities in the investigated soils of both studied areas. Thus, Potential K and Ca deficiency could be greatly compensated by Rb and Sr uptake. The quantities of non – beneficial elements such as Sn, Sb, Te, Cs, Ba and Sc were significant in soils from Nasarawa Eggon but were insignificant in Doma soils. Thus, this study revealed that nutrient content of the soil differs from the nutrient availability for plant uptake and the fertility of investigated soils in both locations depended on the soil pH and textural class. Also, the conditions of the soils at both studied locations, are unfavourable for plant uptake of certain important nutrients and could lead to low crop yields if there is no effective nutrient and soil management.

Isolation and identification of phytase-producing Bacillus and Enterobacter species from Nigerian soils

The bioavailability of phosphorus and other nutrients in feed for monogastrics is restricted by the presence of phytate. Exogenous supply of phytase produced by bacteria and other microbes can enhance the bioavailability of these nutrients and reduce phosphorus pollution. The objective of the study was to isolate bacteria with phytase-producing potentials from soil; which may be employed for the bioavailability of phosphorus and other nutrients in feed for monogastrics in Nigeria. Top soil samples were collected from two dumpsites in Lagos, Nigeria and bacteria were isolated and screened for potentials to produce phytase. The isolates with phytase potential were primarily identified by their cultural and biochemical characteristics and then confirmed using the 16S rRNA sequencing, after which their expressed phytases were quantified. A total of six isolates belonging to three species were identified as phytase producers. Sequence data analyses revealed these to be Bacillus subtilis (2), Bacillus amyloliquefaciens (3) and Enterobacter cloacae (1) with accession numbers MH879827 and MH879832; MH879828, MH879830 and MH879831; and MH879829 respectively. Phenotypic phytase activity was highest in E. cloacae ODS 29 (9.69 ± 0.04 U/ml) and least in B. subtilis ODS 10 (8.83 ± 0.02 U/ml). In conclusion, phytase-producing Bacillus and Enterobacter species were isolated and characterized from Nigerian soils. These bacteria species could be used in biotechnological applications.&#x0D; Keywords: Bacillus, Enterobacter, Monogastrics, Phylogenetic analysis, Phytase

Impact of Abattoir Wastes on Trace Metal Accumulation, Speciation, and Human Health–Related Problems in Soils Within Southern Nigeria

The slaughtering of animals and processing of meats for human consumption generates enormous wastes which are not properly managed in most developing nations including Nigeria. Majority of people in Akwa Ibom state in southern Nigeria depend on meat as their major source of protein, and abattoir wastes are applied in farms as organic manure by some farmers. This study examined the role of abattoir-related waste products in the physicochemical properties, total metal, and metal speciation of the soil. The data obtained were also subjected to some treatments using some environmental models to establish the degree of contamination by the parameters determined, studied locations, and the associated human health problems. Samples were collected from 5 designated abattoirs in Akwa Ibom state. Thirty composite samples were used for the research. Results obtained showed higher levels of pH, electrical conductivity, organic matter, and cation exchange capacity in the abattoir waste–impacted soils than in the control plot. Levels of pseudo total heavy metals were also higher in the studied soils than in the control plot. The mean values of the metals are below 400, 85, 140, 36, 100, and 35 mg/kg of recommended limits for Fe, Pb, Zn, Cu, Cr, and Ni, respectively by the Federal Environmental Protection Agency (FEPA) in Nigerian soil. The results also revealed that Fe and Cr existed mainly in residual fraction. However, Zn, Cu, and Ni existed principally in the form bound to organic matter/sulfide. In addition, we detected that Pb existed mainly in the reducible fraction. Disparities were also observed in the speciation results of the metals between the studied soils and the control plot. Principal component analysis (PCA) indentified that both the geogenic and anthropogenic factors contributed to the accumulation of metals determined in the studied soils. Variable relationships were also observed for the heavy metals determined in the studied soils. Fe showed a high-risk potential, and children were more vulnerable due to its toxicity. We conclude this study was able to expose the consequences of indiscriminate dumping of abattoir wastes on the quality of soil and the associated human health problems.

COMBATING TROPICAL SOIL DEGRADATION: THE ROLE OF NITROGEN FERTILIZER AS A CLIMATE-SMART STRATEGY TOWARDS MAIZE (ZEA MAYS L.) PRODUCTIVE CULTIVATION

Challenges facing humanity over the years include food insecurity, loss of soil and water resources and associated ecosystem disturbance. The rate of hungry people in developing world keeps on increasing and causing death and malnutrition. Food shortages, food insecurity or undernourishment has assumed a global dimension especially as climate change hits the globe with its negative impacts, with more severe cases recorded in the poor-resource African countries. Soil is the natural capital which drives the agricultural sector, being a strong-hole for crop/animal farming, apart-from being a medium for production of raw materials which powers industrial and domestic production. The inherent quality of soil is impaired by various factors including climate variability like excessive rainfall, which ends-up leaching nutrients downstream, thereby resulting in contamination of water bodies with fertilizer/agro-chemical residues. Like most tropical humid soils, the inherent quality of Nigerian soils is generally low, causing rapid degradation of applied nutrients and total crop failure in extreme cases. This has most often been exacerbated by most prevalent land use/agricultural systems, coupled with the problem of over-grazing and indiscriminate deforestation, alongside rapid population expansion with consequent urbanization and industrialization. For effective soil management, especially in the face of climate change, the need for Climate-Smart Strategy (CSS) towards agricultural production becomes imperative, inother to find a Sustainable Approach (SA) to man’s drive towards food production for effective survival. For efficient maize (Zea mays L.) production, application of mineral fertilizer becomes an important aspect for human/animal food production. Field experimentation was conducted at the Teaching and Research Farm of the Cross River University of Technology (Latitude 6° 06ꞌ N and Longitude 8° 18ꞌ E), to evaluate the potential of Nitrogen fertilizer as a Climate-Smart Approach (CSA) for sustainable maize production in the humid tropics. Maize seed variety: Ikom Local White were treated to one level of Nitrogen fertilizer at 0.078 kg ha-1. The treatment was laid out in a Randomized Complete Block Design (RCBD). The treatment were replicated four time to give a total of sixteen (16) field plots. Data collection on plant growth parameters (number of leaves and height of maize) were subjected to Analysis of Variance (ANOVA), while significant means among treatments were separated using Least Significant Difference (LSD) at 5% probability level. Result obtained showed that plots treated with 0.078 kg ha-1 of Nitrogen fertilizer (N-Fertilizer) significantly (p˂0.05) increase growth parameter of maize over the control. Outcome of the study concluded that 0.078 kg ha-1 of N-Fertilizer applied to Maize planted at 1m spacing between plants on bed increase crop growth, and acts as a CSA to remedy the rapid degradation of humid tropical soil productivity, and for environmental sustainability.

Assessment of some heacy metals in soils associated with automobile activities in selected areas of Gombe, Nigeria

This study determined the levels of heavy metals in soils associated with automobile activities in three different sites within Gombe metropolis. Top soil samples were collected from two locations at each sampling site using standard method. The samples were digested and analysed for heavy metals (As, Cr and Ni) using Atomic Absorption Spectrophotometer. The concentration of heavy metals ranged from 0.96 - 1.95 mg/kg at A site, 0.89 - 2.11 mg/kg at B and 0.98 - 2.0 mg/kg at C for Cr, and 1.06 - 2.11 mg/kg at A site, 0.98 - 1.89 mg/kg at B and 0.95 - 0.98 mg/kg at C for Ni while the concentration of As was below detectable limit in all the study sites. The mean concentrations of the metals were compared with that of Department of Petroleum Resources (DPR, 2002) Standard values for Nigerian soil and that of World Health Organization (WHO, 1996). All the concentration of the metals studied were found to be below the DPR and WHO target values. Results of contamination factor (Cf) showed that all the studied sites fall under class 1 low contaminated one with Cr and Ni being found with values greater than one. The values of Pollution Load Index obtained from these three sites (PLI <1) were less than 1 in all the studied sites, thus indicating perfection. Keywords: Assessment, Automobile, Digestion, Heavy metal, Site