Drought and desertification are expected to increase in Sahelian Africa, where there are significant rainfall deficits and extreme temperatures. This study examined the trends in vegetation and climate variables during the period 1986–2023 in Kano, Katsina and Jigawa states, Nigeria. We used Landsat 5 TM, 7 ETM+ and 8 OLI/TIRS and processed spectral indices with Google earth engine platform. For the pilot site in Kano, the year 2015 had the highest minimum (40.19°C), maximum (43.04 °C) and mean (42.63 °C) land surface temperatures (LST), while 2005 had the lowest of these values. The LST for the three states showed a long-term increase over the study years but the normalized difference vegetation index in 1986 was generally low, being 0.19 in Kano, 0.15 in Katsina and 0.17 in Jigawa states, becoming lower still in 2010. Low vegetation condition index close to 0 was dominant in the three study sites, suggesting typically poor vegetation growth and coverage. Mild to severe drought was noticed in Jigawa state, while Kano and Katsina experienced mild drought. Continuous monitoring of these indices would be necessary to assess the overall health of the vegetation, providing insights into environmental changes and their potential impacts on the ecosystem.

Despite its extensive occurrence, over the years, the industrial use of limestone in Cross River State has masked the agricultural potentials of the soils overlying it and so has not been fairly studied. The presence of weatherable minerals in soils is an important index of the stage of weathering and soil development from which the fertility status of the soil can be assessed. The present study seeks to evaluate the fertility implication of some clay minerals in soils developed from limestone geologic formations. Digital elevation models of the study areas were generated. One profile pit was sited in the highest elevation range of Ogoja (OG1) and two profile pits sited in the highest and mid-elevation ranges of each of Yakurr (YK1 and YK2) and Akamkpa (AK1 and AK2). Clay was extracted from the air-dry soil samples obtained from the B and C horizons and subjected to analysis using X-ray diffractometer. The presence of either cambic or argillic subsurface horizons in the entire soils as well as the dominance of kaolinite and quartz over illite, muscovite, dolomite, montmorillonite, witherite and palygorskite qualify the soils in the intermediate to ultimate stage of weathering. Also, the distribution of minerals was such that soils in YK1 and AK1 were the most weathered and least fertile, while those in OG1 and AK2 were the least weathered and most fertile. Furthermore, the vertical variation of clay mineral species is linked to the sedimentary landscape, while differences in the mineral makeup between limestone formations suggest differences that exist between the various formations, leaving soils in the Ogoja area as more fertile due to the abundance of montmorillonite in the soils. Among the minerals, quartz and palygorskite correlated with silt and cation exchange capacity, respectively.

Organic matter exhibit strong variations in nitrogen retention and transformation cycle in soil. However, nitrogen could be altered by seasonal variations, leading us to hypothesize that the open municipal waste dump site in Calabar exposed to dry and wet season could alter nitrogen dynamics in that soil. A total of sixty (60) composite soil samples were collected at different landscape positions (summit crest, shoulder slope, toe slope, interfluve slope, valley floor) of a municipal dump site and a control (no refuse area) during the dry and wet seasons in Calabar and analyzed to ascertain the effects on forms and status of soil nitrogen. The soils were loamy sand across the study location with pH values of 4.50, 7.00, 6.70, 7.30, 5.00, 7.30 (dry season) and 5.00. 7.30, 7.00, 7.40, 5.90, 7.40 (wet season) for the control, summit crest, shoulder slope, toe slope, interfluve slope and valley floor accordingly. Values obtained for total nitrogen (N) from the study site were generally low (<0.21 %), with values for dry season slightly higher than the wet season. NH4+ recorded higher content in wet than in dry season with values ranging between 12.11-14.11 mg/kg (control), 14.60 - 15.90 mg/kg (Summit crest); 18.25 - 20.05 mg/kg (Shoulder slope), 18.30 - 20.20 mg/kg (Toe slope), 12.30 - 14.00 mg/kg (Interfluve slope) and 9.24 -11.07 mg/kg (Valley floor). The Shoulder and toe slopes recorded the highest NH4+ concentration in the wet season. N02- contents documented for the control site were within the ranges of 2.78- 3.20 and 3.22-3.62 mg/kg while the dumpsite had values between 2.49-3.45 and 2.98 -3.22 mg/kg was observed for the shoulder position, the toe slope contained between 2.30-2.75 and 2.70 -2.82 mg/kg, the inter fluve slope had similar ranges of 2.32-2.90 and 2.70-3.08 mg/kg, and the valley floor 2.45-2.60 and 2.78-2.98 mg/kg. N02- values were higher for the wet than dry season. NO3- nitrogen was observed to be excessive across the dumpsite with the highest values > 80 mg/kg obtained at the valley floor. The NO3- values were higher in dry season across the all the landscape positions than in the wet season. The values were equally higher for the dumpsite than the control. It was observed that the dumpsite soils contend excessive NO3- which could be converted to nitrous oxide (N2O) thus contributing to green house (GHG) emissions. It was also noted that seasonal variation did not significantly affect the N content at the different landscape positions of the municipal dumpsite in Calabar. It is highly recommended that municipal waste be sorted and the organic materials composted to harness the rich NO3- content as observed in this research. Received: 22 September 2021 / Accepted: 25 October 2021 / Published: 5 November 2021

The spatial modelling of soil properties provides us with essential and useful information relevant to soil fertility management and environmental protection. The study aims to investigate the ability of empirical Bayesian kriging and principal component analysis, multiple linear regressions with environmental covariates in the modelling of soil properties distribution. For this study, thirty (n = 30) soil samples were obtained at 0–30 cm depth and nine (9) soil-environmental covariates derived from the digital elevation model (Shutter Radar Topography Mission at 30 m resolution) in southeastern Nigeria. The summary statistics revealed high sand content (> 70%) which revealed that the soils of the humid tropics developed on the coastal plain parent material are coarse-textured. Pearson correlation matrix revealed a significant but weak correlation between soil properties and soil-environmental variables. Using empirical Bayesian kriging interpolation, the cross-validation results revealed an acceptable prediction for magnesium, potassium, phosphorus, pH and total nitrogen (R2 > 0.5 with RMSE closer to 0). The principal component analysis reveals that principal component 1 to principal component 5 could interpret 78.1% of the total variability of soil properties. Modelling each soil property using multiple linear regression with the derived soil-environmental covariates, the study noted that only magnesium gave the best model fit with 50.9% of the soil-environmental covariates explaining its variability, while other soil properties presented unacceptable models. Therefore, to improve soil property prediction through multiple linear regression, more observation points are recommended to interpret better the performance of multiple linear regression over flat terrain system.

This study investigated the current state and pollution loads of heavy metals in soils developed on diverse parent materials in southeastern Nigeria. Cu, Mn, Zn, Fe and Al were analyzed to estimate pollution loads and ecological risk of the area. The result showed soils developed on granite gneiss to have a higher concentration (measured in mg kg(-1)) of Cu (1.79), Mn (78.39) and Zn (28.53), while soils developed on Biotite hornblende gneiss and quartz-mica-schist had a higher concentration of Fe (>= 18) compared with other parent materials. The contamination factor for Fe, Zn, Mn and Cu was low, whereas Al was moderately to considerably contaminated except for soils in S2 (0.362), S3 (0.662), S6 (0.142), S9 (0.661), S11 (0.803) and S15 (0.499). The result of the pollution load index indicated an unpolluted condition (PLI < 1). Excluding Al, the soils were practically uncontaminated with Zn, Cu, Fe and Mn, based on the Geo-accumulation index and Quartz-mica-schist was enriched by Zn in S6 (1.325) and showed low ecological risk (Er < 40) and (IR < 150). Hence, the soils in the studied communities are still in a safe state to be used for crop cultivation without any fear of metal contamination.

Background and Objective: Most of the soils of South-eastern Nigeria are strongly acidic.Liming these soils for profitable crop production requires the assessment of the soil properties and then developing model equations for calculating liming rates.This study aimed to assess the soil properties and then develop model equations and curves for quick calculations of liming rates.Materials and Methods: Soil samples were collected at 40 different locations in Cross River and Akwa Ibom States and analyzed.An incubation study was also performed to monitor changes in pH bi-weekly in the laboratory.Neutralization curves were constructed by plotting a maximum rise in pH against lime rates.Results: The soils were separated into particle-size classes, A (sandy clay loam and clay soils) and B (sandy loam and loamy sand soils).Soil properties were higher for group A than B. Multiple regression equations created provided several equations for calculating Lime Requirements (LR).The equations were: Group-A: LR = 0.33+0.28)pHxOM+0.18)pHxclay[R 2 = 0.855].Group-B: LR = 0.98+0.58)pHxOM [R 2 = 0.552].Conclusion: Over-liming can generate alkaline conditions that may create solubility problems.Therefore, both the regression equations and the curves are useful tools for quick determinations of lime requirement.

The recent proliferation of agricultural activities (farming and grazing of animals) within hospital premises is a major concern, leading our team of researchers to conjecture that such an environment may have adverse effects on plants, animals, and human health. This research sought to assess the microbial and heavy metal status of soils under cultivation within hospitals in Calabar, with a view to determining the implications for food and farmer's safety. Four hospitals with open dumps and one with an incinerator, all with ongoing farming activities within one meter from the hospital dump-sites were identified within Calabar metropolis for the study. Crops were cultivated less than 1 m distance around the open dumps and incinerator within the hospital premises. Forty-eight composite top (0-15 cm) and sub (15-30 cm) soil samples were randomly obtained from farms within the five hospitals and a control site within Calabar metropolis and analyzed for microbial properties and heavy metals zinc (Zn), lead (Pb), copper (Cu), chromium (Cr), and iron (Fe) contents. Two edible plants from each sampling site were also collected for heavy metal detection. The results showed that the soils were sandy loam in texture. The pH of soils in the study site ranged from strong to slightly acid in reaction. The results for microbial analysis indicated a proliferation of mostly pathogenic organisms at the hospital sites. The following bacterial isolates were identified from the hospital sites: Clostridium spp., Bacillus spp., Pseudomonas spp., Micrococcus spp., Corynebacterium spp., vibrio spp, E.coli, Streptococcus spp., Salmonella spp., Staphylococcus spp., klebsiella spp., Nocardia spp., Enterococcus spp. and Mycobacterium spp. Probable fungal isolates from the hospital sites include Aspergillus spp., Mucor spp., Scopulariopsis spp., Verticillium spp., Paccilomyces spp., Phoma spp., Rhizopus spp., Alternaria spp. Drechslera spp, and Microsphaeropsis spp. The metal pollution index (MPI) of the hospital sites indicates slightly to moderate pollution with Cu, Pb, Zn and very severe pollution of Cr and Zn at hospital 1. Generally, the hospital soils were excessively polluted with Fe. Based on the metal pollution index (MPI) ranking these levels of heavy metals can exert negative effects on plants, soil ecosystem and the environment in general. This was evident in the accumulation of heavy metals in soil and plant tissue grown at the hospital sites than those from the control site. However, the bio-accumulation of Zn, Cu, and Fe in plants from the hospital sites were below the standards by FAO/WHO. Owing to the preponderance of pathogenic organism observed and the increasing levels of heavy metals in soil and plants recorded in this research, it is recommended that agricultural activities should not be carried out at hospital sites to prevent contamination of pathogenic organisms by farmers and to ensure food safety.

Coastal areas in Anantigha are utilized as dumpsite for industrial and domestic wastes including effluent from local industries and inhabitants of the area despite their usage for crop cultivation. Thus, the present study was designed to assess the concentration, pollution load and ecological risk of heavy metal in Anantigha coastal area. Standard pollution indices such as contamination factor (Cf), degree of contamination, pollution load index (PLI), enrichment factor (EF), geo-accumulation index (Igeo) and ecological risk index were deployed to assess the level of heavy metals contamination in the area. The results showed that the sediment was acidic under dried conditions and low in conductivity. The mean concentration levels of all the heavy metals were lower than their mean background values except for Al. The orders of dominance for concentration of heavy metals were: Al>Fe>Mn>Cu>Zn (Station 1) and Al>Fe>Mn>Zn>Cu (Stations 2, 3 and 4). Analyzed data showed that the sediments in the area are contaminated with Al with Igeo result showing station 2 and 4 been moderately to heavily contaminated with Al while station 4 was heavily contaminated with aluminium. Station 1 had low degree of contamination, whereas station 2 and 4 had moderate degree of contamination, and station 3 showed considerable degree of contamination. The PLI result indicates unpolluted condition and the area were not enriched by the studied heavy metals as shown by EF values. Hence, the sediment in Anantigha coastal marine area was classified as having low ecological risk factor. However, the levels of these metals are not static; there is tendency for increase as a result of increased human input and activities. Hence, there is a need for regular soil testing.

A study was carried out to characterize the physico-chemical properties and micronutrients status of soil developed on Anantigha coastal marine sediment in Calabar. Four profile pits were dug along the coastal area and soil samples taken from identified horizons were subjected to laboratory routine analysis. The data obtained were subjected to one-way Analysis of variance (ANOVA). The predominant colours observed for the study were mostly; dark greys (2.5YR 4/1) and black (10YR 2/1). The soil were massive in structure and has very sticky and very plastic in consistence and the boundary observed was mostly diffuse smooth and clear smooth. Percent sand fraction was the dominant particle size fraction except in profile 4. Soil in profile 1 was made up of sandy loam, silt loam loamy sand, loam and sandy clay loam, while soil in profiles 2, 3 and 4 were predominantly sandy loam, sandy clay loam and silt loam, respectively. Soil pH measured in water and calcium chloride were very strongly acidic and increases with horizon depth with pH mean values of 2.5 in H 2 O and 2.2 in CaCl 2 for surface soil and 2.7 in H 2 O and 2.4 in CaCl 2 for sub- surface soils. The organic carbon and organic matter content of the surface soils were high and those of the subsurface soils were moderate. The mean electrical conductivity was 2.0 and 2.3 dsm -1 for surface and subsurface soils respectively. The exchangeable cations (Ca 2+ , Mg 2+ , K + and Na + ) were moderate to high in both surface and subsurface soils. The exchangeable acidity (Al 3+ and H + ) were high. CEC was low in surface soils and high in subsurface soils. Base saturation in both surface and subsurface soils was below 50 %. The results obtained for available micronutrients showed that the mean values for Zn, Cu, Fe and Mn were 1.43, 0.92, 134.65 and 5.05 mg/kg for surface soil and 1.89, 1.89, 121.29 and 1.48 mg/kg for subsurface soil. Zn and Cu were generally “low” to “medium” in all the horizons of the pedons while Fe and Mn values were “high”. Agronomic practice such as liming that will raise soil pH is recommended so that levels of nutrients that are below the critical levels will be made available in the soil. Keywords: Morphology, micronutrients, physicochemical, marine sediment

The comparative assessment of wetland and coastal plain soils for agricultural productivity were studied. The investigation was carried out in two areas: Atimbo and Obufa Esuk in Calabar, Cross River State. The dominant particle size in both coastal and wetland soil was sandy texture. The mean bulk density values of 1.35 g/cm 3 and 1.30 g/cm 3 were obtained for Atimbo and Obufa Esuk coastal plain soil while 1.33 g/cm 3 and 1.30 g/cm 3 were obtained for Atimbo and Obufa Esuk wetland soil respectively. Total porosity in wetland soils was lower than coastal plain soil whereas moisture content in wetland soil was higher than coastal plain soil. Except Ap horizon in Atimbo coastal plain soil, the pH observed for the studied soils were all below pH of 5.0 unit which signifies high acidic condition. The mean organic carbon content in coastal plain soil was lower than wetland soil. Available phosphorus in the studied soils were high with Atimbo and Obufa Esuk coastal plain soil having a mean value of 32.10 and 32.42 mg/kg respectively, whereas those in Atimbo and Obufa Esuk wetland soils were 32.73 and 33.88 mg/kg respectively. The exchangeable calcium content obtained for both coastal and wetland soils were all below the critical limit of 5.0 cmolkg -1 . Although exchangeable magnesium content was low in both soils but wetland soils was only slightly below the critical value of 1.5cmol/kg when compared to coastal plain soil. Both wetland and coastal plain soils were below (>0.2 cmolkg -1 ) critical level of K in soils of the zone. Also, exchangeable Na in both soil were low and below 0.3 cmol/kg limit and are adequate for cultivation of arable and tree crops. ECEC in both soils were low whereas percent base saturation was high. The mean C:N ratio in Atimbo and Obufa Esuk coastal plain soil were 11.45 and 15.48 respectively. Comparatively, the C:N ratio in Atimbo and Obufa Esuk wetland soils was slightly higher having a mean value of 16.39 and 18.14 respectively. This also reflect low rate of decomposition because of anaerobic condition of the soil. The Mg:K ratio were low in both soils. The Ca:Mg ratio values were high in wetland soil when compared with a normal range of 3:1-5:1 for productive soils and was low for coastal plain soil. Per cent silt content, moisture content, and exchangeable sodium of soil sample analyzed from wetland and coastal plain soil in Atimbo were significantly different (p<0.05). The result of the studied soils indicated that coastal plain soil is already losing its fertility status as typified by low values of organic carbon, total nitrogen, Exchangeable cations and high acidity couple with low moisture content; hence there is need to harnessed wetland soil for crop productivity. Wetland soils could be exploited for the cultivation of rice, oil palm, coconut, plantain, pineapple and sugar cane with judicious application of lime, and N and K fertilizers since these crops can perform well under acidic condition. Keywords: Wetland soil, coastal plain soil, soil fertility, soil properties

Soils derived from Awi sandstone formation in Awi, Akamkpa LGA of Cross River State, Nigeria were studied along a toposequence with a view to classifying them taxonomically, assessing their potentials and suggesting appropriate management strategies. Three profiles were dug at the crest, middle slope and lower slope of the landscape. The morphological properties of these soils: colour, soil structure, soil consistence, drainage, boundaries and root inclusions were recorded in the field. These soils were deep (>100 cm), with sandy loam surface texture over sandy clay to sandy clay loam subsurface textures. These soils had hues of 10 YR 5 YR with sub angular blocky structure and a sticky consistence (wet) and bulk density of 1.0 1.7 g/cm with total porosity of 22 38 %. Soil reactions in H2O were acidic (pH 4.75.8). These soils have Organic Carbon of 14.4 38.1 g/kg; total nitrogen 1.2 3.3 g/kg; available phosphorus 4.18.3 mg/kg; exchangeable acidity (H) 0.5 11.9 cmol/kg; Cation Exchange Capacity (CEC) 2.0 6.0 cmol/kg and base saturation 20.0 52.5 %. The soils were classified according to the USDA Soil Taxonomy as Typic Kandiudults and correlated as Dystric Acrisols as per FAOWRB for soil resources. It is recommended that soils fertility management practices should focus on reducing leaching of basic cations from the soils through mulching, planting of cover crops, crop rotation, adoptions of zero tillage as well as planting of acid tolerant crops and application of liming materials to reduce the strong acidity in these soils.

This research investigated variability among soil properties in soils overlying shale, sandstones and limestone parent materials. The result showed variability in percent sand, silt and clay content in both surface and subsurface soil. The texture ranged from clay, loam, sandy clay to sandy clay loam. The soils were acidic except those developed on limestone. The organic carbon contents of the soils were low to moderate. Total nitrogen was low while available phosphorus was high. In all parent materials exchangeable bases consistently decreased with geomorphic surfaces and were in the magnitude of Ca > Mg > K > Na. The result of the study also showed that landscape position (crest, middle slope and valley bottom) significantly influences sand and clay content, available phosphorus, and exchangeable acidity (H) and the crest had the highest sand content, middle slope had the highest clay content, valley bottom had highest available phosphorus while the crest and valley bottom had the highest exchangeable H. Also, parent materials (shale, sandstone and limestone) significantly influences sand and clay content, pH, organic carbon, available phosphorus, exchangeable Ca and Mg, exchangeable acidity (Al and H), ECEC and BS. pH and base saturation within and across the three parent materials consistently had low variability Original Research Article Afu et al.; IJPSS, 20(6): 1-14, 2017; Article no.IJPSS.38317 2 class (CV< 15%) whereas soil texture particularly percent silt and Al consistently had high variability class (CV >35%). This result suggest that uniform management practices for soil properties with high variability alongside with those having low variability in Odukpani soils can leads to failure of crops to response to such management practices and yield loses are inevitable.

Wetland soils developed on limestone parent materials were characterized and classified. In the study, eight (8) profile pits were sunk in 3 sites within Cross River State in 2006, described and sampled according to FAO (1988) guidelines. The samples were analysed in the laboratory using routine methods. Results obtained for morphological studies and physicochemical analysis showed that the soils were generally deep to shallow, moderately well drained to poorly-drained with weak red to light grey, Dark reddish brown to reddish brown, yellowish brown in colour. Thesoils are weak, medium, and crumb, moderate and sub-angular blocky structure. The texture ranged from sandy loam, silt, loam, loamy sand, sandy clay and clay loam. Bulk density values ranged between 1.20 g/cm3 and 1.85 g/cm3 with a mean of 1.37 g/cm3. Particle density values ranged from 2.18 g/cm3 to 3.70 g/cm3 with a mean of 2.74 g/cm3. The soils showed total porosity of 50% on the average which indicated good soils for maximum plant growth. The soils are slightly alkaline to moderate alkaline in reaction. Organic matter, total nitrogen, Available phosphorus contents,calcium, magnesium, potassium, and sodium contents were rated as low to moderate. An effective cation exchange capacity value of 10.36 cmol/kg was rated moderate with base saturation values above 82 per cent for these soils. The soils were classified as Inceptisols and Alfisols.