DEPARTMENT OF SOIL SCIECNE AND LAND MANAGEMENT

The experiment was carried out at the experimental site of Faculty of Agriculture, University of Benin, Benin City, to determine the effect of maize kidney bean intercrop on some properties. The experiment was laid out in a randomized complete block design (RCBD), with three (3) levels of same treatment and replicated three (3) times. The treatment levels are sole kidney bean, sole maize and maize-kidney bean intercrop. Soil parameters determined include; pH, Total Nitrogen, Total organic carbon (TOC), Available phosphorus, Potassium, Calcium, Magnesium, Exchangeable Acidity, Base saturation, Soil textural classes (sand, silt and clay), these were analyzed before sowing and after harvest. Plant nutrient concentrations, growth parameters, and yield components were also measured. Results showed that intercropping significantly improved soil fertility, with higher pH (5.56), TOC (12.30 g/kg), and TN (0.73 g/kg) compared to sole maize. Intercropping enhanced nitrogen, phosphorus, potassium, and magnesium concentrations in kidney bean tissues, while maize showed reduced nutrient concentrations under intercropping, indicating differential nutrient uptake between the two crops. Agronomic performance of kidney bean improved under intercropping, with higher stem girth, vine length, and number of leaves, while maize yield was reduced slightly. The yield of kidney bean was not affected by intercropping at 5% level of significance while the yield of maize was significantly (p <0.05) reduced from 7.23t/ha to 6.45t/ha. In conclusion maize-kidney bean intercropping enhances soil fertility, improves nutrient uptake, and improve yield

The study was carried out to investigate potassium availability in soils of an oil palm lantation invaded with different weed types in Ekasa Village, Ovia North East Local overnment area of Edo State, Nigeria. Soil samples were collected at two different depths (0-15cm and 15-30cm) with three replicates each, at four different weeds-invaded areas overing at least one acre each. The weeds investigated are; Spear grass (SR) (Imperata cylindrica), Guinea grass (GR) (Panicum maximum), White weed or goat weed (WR), Ageratum conyzoides), and Siam weed (Chromolaena odorata) (CR). The results showed that the soil of the plantation is loamy sand which is moderately acidic (mean pH value 4.67). In all the weeds investigated the potassium contents in the soils at 0-15cm depth are very low (WR=0.1724 Cmol/kg, SR=0.1008 Cmol/kg, GR=0.1838 Cmol/kg, and 0.1478 Cmol/kg) and these values are reducing with increasing depth. At both 0-5cm and 15 – 30cm depth, there are no significant differences in the potassium contents mong the soils of all the weeds investigated. The portions with CR and GR have high and significantly same organic carbon contents at 0-15cm (23.61g/kg and 23.01g/kg respectively) but moderate organic carbon content at 15-30cm (18.22g/kg and15.23g/kg respectively) which are also significantly the same, while the portions with WR and SR have moderate organic carbon contents at both depths (15.49g/kg, .91g/kg and 42g/kg, 14.76g/kg respectively). The Organic carbon content in the CR portion was the highest (23.61g/kg) followed by the portion with GR (23.01g/kg) at 0-15 cm depth while the ortion with WR is the lowest (15.49g/kg). The 15-30cm depths also followed the same end. There was a significant difference between the mean value of organic carbon content of the portion with WR (15.49g/kg) and CR (23.61g/kg). There were no significant differences between the nitrogen value in soils of CR and GR at both depths. The results also showed that the soils of the portion with CR has significantly the highest nutrients reserve of followed by GR, then SR while WR has the lowest fertility levels.

The status and distribution of some selected oxides and monosaccarides research on soils of cowpea and maize farms was carried out in faculty of Agriculture, university of Benin suitated in Ovia North east of Edo state,Nigeria. 24 soil samples was collected using a factorial experimental design of 2×4×3 .I.e two different farms at four different depths(0-30,30-60,60-90,90-120cm) replicated three times.The results shows that the soils were strongly acidic for the pH of both farms, the oxides of iron was higher in soils of maize farm compared with cowpea farm.Also, for monosaccarides, Arabinose was higher compare to glucose, galactose,mannose and xylose for both farms(kuzyavok,Y ,2006y). The correlation coefficient matrix showing the relationship between forms of iron and manganese oxides from maize farms was negatively correlated and significant at pH while the correlation coefficient matrix showing the relationship between the oxides of iron and manganese from cowpea farm was positively correlated and significant with clay.

Heavy metals are naturally occurring metallic elements with high atomic weights and densities at least five times greater than water which due to their persistence, toxicity, and bio-accumulative nature, they pose significant environmental and health risks (Ali et al., 2020). Lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As) are toxic even at low concentrations (Tchounwou
et al., 2020). Heavy metal bioaccumulation refers to the progressive increase in concentration of toxic metals (e.g., Pb, Cd, Hg, As) in living organisms over time, primarily through uptake from contaminated water, soil, or food, exceeding environmental levels due to slow excretion rates (Ali et al., 2023). This process involves the absorption and retention of heavy metals in tissues of organisms, leading to higher internal concentrations than their surroundings, with potential transfer across food chains (biomagnification) (Javed et al., 2022).

This research work was conducted in the University of Benin, Benin City, with the aim to determine plant nutrient status under different land use types within the Ugbowo campus of the University of Benin, Benin City, Edo State, Nigeria. Soil samples were collected from twelve (12) sites, (three each) from four (4) different land use types, namely: Arable land, Fallow land, Grazing land, and Forest land at depths of 0-15 cm and 15-30 cm. Soil samples from same land use and same depth were bulked to make composite samples which were taken to the laboratory for analysis using standard procedures. Some of the parameters analyzed for are, the Soil pH, Total Organic Carbon (TOC), Total Nitrogen (N), Available Phosphorus (P), Exchangeable Acidity, Exchangeable Base (BS), particle size distribution, Electrical conductivity, Potassium (K) calcium (Ca), Magnesium (Mg) and Effective Cation Exchange Capacity (ECEC). Results showed that the top soils belong to the textural class of loamy sand. Sand content decreased with depth in all land uses while clay content increased with depth. pH was least in arable land, having pH 4.93 and highest in grazing area, having pH 6.2. pH decreased with depth in all land uses except in grazing area, where it increased. TOC, N, P, K, Ca, Mg, Na and sand content, all had their highest values in the top 15 cm of the soils but decreased down the profile while H, Al, and clay values increased with depth

This study was carried out at Iguzama community to assess the capability for arablecropproduction. The methodology involved rigid grid soil identification and mapping at adetailedscale. The survey produced four ( 4 ) mapping units(site A : upper and lower slope, siteB: upperand lower slope) and each was represented by a pedon. The pedons were described appropriately.Samples were collected from each pedon and taken to the laboratory for analysis usingstandardprocedure. The results revealed that the entire study area had a sandy top soil ( 0-20cm) withsand fraction of particle size ranging from 660 gkg1 to 960 gkg1 , silt ranged from10gkg1to44 gkg1 and clay had values ranging from 30 gkg1 to 320 gkg1 . The nutrient reservewasequally low as expressed by the low potassium values ( K < 0.2 cmolkg ) which rangedfrom0.01cmolkg1 to 0.29 cmolkg1 : and low Organic Carbon values ( 1.30gkg1 to 23.13gkg1).The mean values for : sand fraction in the soils ranged within 787gkg- ¹ to 886 gkg-1 for silt 15gkg- ¹ to 26.8gkg-1 and clay from 88gkg- ¹ to 190gkg. The CV of pH for pedon 1a was 10.5%with a ranging of low variability as well as its sand fraction which had CVvalue of 6%. Inpedon1b the pH , AI , base saturation and sand fraction were ranked as low variability withCVvaluesof 6.2 , 0.42%, 13.9 % and 11.5% respectively . The pH , ECEC , CEC and sandfractionofpedon 2a under site B were in low variability with CV values of 9.68%, 13.67%and5.1%respectively. The silt fraction, base saturation and pH of pedon 2b had lowvariabilitywithCVof8.37%, 12.19 % and 4.4% . Based on morphological characteristics and laboratoryresults, thepedons were evaluated for their capability to support arable crop production and that 1.65haor41.25 % occupied by pedon 1a (lower slope), 2.64ha or 66% occupied by pedon 1b (upper slope),6.4ha or 53.33% occupied by pedon 2a (lower slope) and 5.69ha or 47.416%occupiedby2b(upper slope) fell on aggregate class III based on the law of minimum. Therefore, theyaresuitable for cropping and intensive grazing. Soil conservation practices and sound managementare needed to overcome the moderate limitations to cropping use

This experiment was conducted in the green house of the Department of Soil Science and Land Management, Faculty of Agriculture, University of Benin, Benin City. The aim of the study was to ascertain the heavy metal (Pb, Cd, Cr and As) contents of Amaranthus cruentus raised on soils from dumpsites from different land uses in the University of Benin. The experiment was laid outin a Completely Randomized Design (CRD) with three replicates. Six different dumpsites were carefully selected in the Ugbowo campus of the University of Benin, three from learning centers and the other three from residential areas (students hostel). Soils collected from the dumpsites were filled into buckets and Amaranthus seeds were planted in them, and harvested at maturity. Soil and plant samples were taken to the laboratory to determine the physicochemical characteristics and heavy metal content present. Data obtained were subjected to Analysis of
Variance (ANOVA) while LSD was used to separate means at 5% level of probability. Results obtained shows that soils from the dumpsites belong to the textural class: sand. Their pH was
moderately acidic and their TOC contents were 19.60 and 21.50 g/kg in the Learning center and Residential area respectively. The heavy metal studied were present in both soils, and there was no significant difference between the heavy metal content across the two dumpsites. The peak lead (Pb) content (1.30 mg/kg) was obtained in the learning center while the peak Cd, Cr, and As contents (0.037 mg/kg, 0.040 mg/kg and 0.040 mg/kg respectively) were recorded in the residential area.

The soils of Owan East Local Government Area of Edo State were studied in order to update the classification, mapping and suitability evaluation done by Federal Department of Agricultural Land Resources (FDALR 1985). Soil mapping was at the reconnaissance scale; soil classification was according to the USDA and WRB systems while suitability evaluation was patterned after FAO guidelines, as modified by several scientists for rubber, oil palm, cacoa, maize and cassava. Reliability of the soil maps were
determined by the variability indices of: Coefficient of Variation (CV), Variance Ratio Test (VRT), Inter – class Correlation Coefficient (P1), Relative variance (RV) and its Complement (1 – RV). Validation of the updated work was done through a free soil survey procedure and suitability assessment for rubber on the 17.7 ha parcel of land for RRIN within the project area. The study revealed that six major mapping units were found and classified as Alfisols/Lixisols, (occupying some 66,160.26 ha), Inceptisols/Cambisols (37,803.07 ha) and Entisols/Arenosols (19,471.17 ha). The FDALR work showed two mapping units classified as Alfisol/Lixisol and without areal distribution of the units. In terms of the reliability of the soil maps for the study area, the results showed that the findings in this study is quite superior to that of the FDALR. In terms of suitability for the selected crops, for the current findngs, 70,201.5 ha (56.87%) was best suited for maize, cassava and cocoa, while 26, 624.49ha (21.57 %) was best suited for cocoa only. An area of 19,471.17 ha (15.77%) was best suited for maize, cassava and rubber while an area of 7,137ha was found not suitable for any of the 5 crops under study. The FDALR study had the same tree crops examined for their suitability, no area was
rated unsuitable and only one map was used to represent all the crops, while for arable crops, no specific crop was mentioned and it had only one map and two suitability classes. For Indices of variability: FDALR study had 46 % homogeneity within mapping units by CV while it was 87 % for the 2019 findings. For variance ratio test (VRT), no property was significantly different for the 1985 study while for the 2019, 13 properties were significantly different; Intra class correlation coefficient (pi) , in the 1985
work only CEC was accurately predicted (pi > 0.5) while in the 2019 work 7 properties were accurately predicted (pi > 0.7); for Relative variance only one property, CEC was accurately predicted compared with 9 properties (RV = 0.26 – 0.53) - 1985 and 2019 respectively. The results of the 17.71ha classification and suitability ratings agreed with that of the updated findings – being largely Inceptisol/Cambisol and only marginally suitable for rubber cultivation. Thus it can be concluded that while the FDALR study served its purpose as a pioneering attempt and hence overdue for updating. The study was highly necessary for accurate prediction of crop performance and sustainable management of the study location.

This research work was conducted in the University of Benin, Benin City, with the aim to determine plant nutrient status under different land use types within the Ugbowo campus of the University of Benin, Benin City, Edo State, Nigeria. Soil samples were collected from twelve (12) sites, (three each) from four (4) different land use types, namely: Arable land, Fallow land, Grazing land, and Forest land at depths of 0-15 cm and 15-30 cm. Soil samples from same land use and same depth were bulked to make omposite samples which were taken to the laboratory for analysis using standard procedures. Some of the parameters analyzed for are, the Soil pH, Total Organic Carbon (TOC), Total Nitrogen (N), Available Phosphorus (P), Exchangeable Acidity, Exchangeable Base (BS), particle size distribution, Electrical conductivity, Potassium (K) calcium (Ca), Magnesium (Mg) and Effective Cation Exchange Capacity (ECEC). Results showed that the top soils belong to the textural class of loamy sand. Sand content decreased with depth in all land uses while clay content increased with depth. pH was least in arable land, having pH 4.93 and highest in grazing area, having pH 6.2. pH decreased with depth in all land uses except in grazing area, where it increased. TOC, N, P, K, Ca, Mg, Na and sand content, all had their highest values in the top 15 cm of the soils but decreased down the profile
while H, Al, and clay values increased with depth. Grazing area had the highest amount of nutrients, which are; TOC (25.21 g/kg), available P (16.45 mg/kg), K (1.60 cmol/kg), Ca (1.31 cmol/kg) and Na (0.21 cmol/kg), while the forest had the highest concentration of N (1.93 g/kg). Arable land had the least concentration of nutrients.

This research work was conducted in the University of Benin, Benin City, with the aim to determine plant nutrient status under different land use types within the Ugbowo campus of the University of Benin, Benin City, Edo State, Nigeria. Soil samples were collected from twelve (12) sites, (three each) from four (4) different land use types, namely: Arable land, Fallow land, Grazing land, and Forest land at depths of 0-15 cm and 15-30 cm. Soil samples from same land use and same depth were bulked to make composite samples which were taken to the laboratory for analysis using standard procedures. Some of the parameters analyzed for are, the Soil pH, Total Organic Carbon (TOC), Total Nitrogen (N), Available Phosphorus (P), Exchangeable Acidity, Exchangeable Base (BS), particle size distribution, Electrical conductivity, Potassium (K) calcium (Ca), Magnesium (Mg) and Effective Cation Exchange Capacity (ECEC). Results showed that the top soils belong to the textural class of loamy sand. Sand content
decreased with depth in all land uses while clay content increased with depth. pH was least in arable land, having pH 4.93 and highest in grazing area, having pH 6.2. pH decreased with depth in all land uses except in grazing area, where it increased. TOC, N, P, K, Ca, Mg, Na and sand content, all had their highest values in the top 15 cm of the soils but decreased down the profile
while H, Al, and clay values increased with depth. Grazing area had the highest amount of nutrients, which are; TOC (25.21 g/kg), available P (16.45 mg/kg), K (1.60 cmol/kg), Ca (1.31 cmol/kg) and Na (0.21 cmol/kg), while the forest had the highest concentration of N (1.93 g/kg). Arable land had the least concentration of nutrients.