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Full Research Article

Appraisal of Soil Fertility: A Case Study of Okpare-olomu Farm Settlement in Ughelli South Local Government Area, Delta State

S
S.A. Ojobor1,*
https://orcid.org/0000/0002-6835-6797
G
G.O. Okogu1
O
O.F. Elike2
1Department of Agronomy, Faculty of Agriculture, Delta State University Abraka, Nigeria.
2Department of Soil and Land Resource Management, Faculty of Agriculture, Dennis Osadebay University, Asaba, Nigeria.

ABSTRACT

Background: Fertilizer application without soil test has resulted to nutrient imbalance and toxicity leading to widespread yield depletion. Appraisal of soil fertility status of Timpher Farms Limited in Okpare-Olomu, Ughelli-south local government area of Delta State.

Methods: Soil samples and their coordinates were taken and soil quality indicators were analyse using standard procedures. Soil fertility index and Soil evaluation factor were calculated and used to delineate the arable farm area into nutrient management zones. Data were analyzed with descriptive statistics and correlation coefficient was used to establish the relationship among soil variables.

Result: The soil is loamy sand, strongly acidic with an average soil organic matter while total nitrogen was low. Available P was moderate, exchangeable bases were low except for Ca that was moderate. Base saturation was low whereas CEC was moderate but dominated by non-basic cations. The micronutrients were adequate for crop production. Larger proportions of the farm falls within the low soil organic matter and total nitrogen management zones; indicating that the farm had low soil fertility.

INTRODUCTION

In the current unprecedented food challenges, soil fertility synthesis could be a potent tool for improving crop production (Dandasena et al., 2024 and Sachan et al., 2022). Nutrient management practices adopted to produce economic yield and at the same time maintain minimal nutrient leakage can only be achieved through timely evaluation of soil fertility (Dandasena et al., 2024 and Sachan et al., 2022). Soil quality indicators that determined the fertility and are evaluated after analysis. Soil fertility evaluation measures the availability of plant nutrients and also estimate the capacity of the soil to supply crop the elements (Ayodele et al., 2019 and Ojobor et al., 2021). Up-to-date information on soil characteristics is essential in sustaining production of crops. Lack of basic information on the levels and management of soil properties has led to continued yield decline (Nwawuike, 2023 and Iraiyanban et al., 2025). The limited information on site-specific fertilizer amendment arouses the need for assessing the nutrient status of soil. This will aid in developing appropriate management policy as the soil resources (Ayodele et al., 2019). Cropping sustainability requires frequent evaluation of soil quality as different land uses change the properties.
       
Soil is indispensable natural resource that plays a relevant role in improving crop production however, inadequate information about the potential uses are lacking. Soil fertility assessment will provide useful data on the nutrient and their distribution that are crucial for implementation of sustainable management (Ofem et al., 2023). Understanding soil fertility variation could be tools in decision making (Okebalama et al., 2024). Therefore, background information about the soil fertility is required before soil amendment (Delsouz et al., 2017). A basic aspect of sustainable crop production is monitoring of soil fertility (Dandasena et al., 2024) and this helps to provide key information on how to improve the soil because, limiting factors will be identify that will enable management guideline implementations (Hadole et al., 2019 and Iraiyanban et al., 2025).
       
Okpare-Olomu is a notable farming community in Ughelli south local government area under Delta central agricultural zone. The community is predominantly known for cultivation crops and houses different farm settlements. Timpher Farms Limited (about 40 hectares) is one of such that was newly established. For proper planning for various uses, there is need to critically identify the limiting nutrients, this will guide the implementation of management options for the area.  On this premise, the study tends to investigate the nutrient status and create nutrient management zones for the farm.

MATERIALS AND METHODS

The study area
 
The study was conducted at Okpare-Olomu in Ughelli North Local Government Area, Delta state. It is situated between latitude N 502515611 and Longitude E 505415011, 21.1 meters elevation above sea level and falls within the rainforest agro-ecological zone of Nigeria. The land is relatively flat with different areas planted to Oil palm, Cassava, sparse distribution of Maize, several grasses and shrubs.
 
Soil sampling, handling and laboratory analyses 
 
Soil samples were collected with an auger at 0-15 cm depth, air dried and taken to the laboratory for analysis. Standard laboratory methods were determine the soil properties. Sampling points and their coordinates were taken.
 
Soil fertility index and soil evaluation factor (SEF)
 
The SFI and SEF were examined and used to categorize the farm into nutrient management zones.
 
Data analysis
 
All data generated were subjected to simple descriptive statistics while correlation analysis was used to show their relationships.
 

RESULTS AND DISCUSSION

Particle size distribution, pH, organic matter and macronutrients of the farm
 
The soil particle size fractions indicate mean clay content to be 9.1%, silt was 8.7% and sand was 82%. The values ranged from 7.0-13±1.9% with coefficient of variation (CV) of 2.1% clay, 5.0-13±2.9% with CV of 30% silt and 78-86±2.4 with CV of 2.9% sand, indicating dominance of sand with low spatial heterogeneity (Table 1). Considering the textural class of the area, the soils are relatively not compacted.

Table 1: Particle size distribution.


 
pH, organic matter and macro nutrients of the farm
 
pH
 
The farm area fell within the strongly acidic category with a mean value of 4.9, the range was 4.2-5.4±0.3 with CV of 6.2. The pH of the study area is not considered suitable for most crops, tough the variability was low (Table 3).

Organic matter
 
The mean soil organic matter was 1.8% and the range was 0.89-3.58±0.70% with CV of 41.5% (Table 2). About 60% of the study area was low, 26.7% was moderate whereas, only 13.3% of the total area of the farm was high, showing that the study area was highly variable in organic matter content.

Table 2: Particle size distribution, pH, organic matter and macro nutrients of the farm.


       
Average TN was 0.15%, the values ranged between 0.11-0.23±0.04% with a CV of 23%. Higher per cent (60%) of the farm was low, only 26.7 and 13.3% were medium and high, respectively. The mean available P was 10.4 mg/kg, it ranged from 7.5-14.9±2.1 mg/kg with CV of 19.7% (Table 3). About 46.7% of the farm area was low whereas, 53.3% were moderate that is, no area was found to be high. All parts of the farm had low Na and had similar value of 0.08 meq/100 g in the entire farm. Potassium was also generally low, only less than 10% of the land was high in available K. The mean value was 0.08 meq/100 g, it ranged from 0.03-0.39±0.08 meq/100 g with a very low CV of 0.06%. Mean Mg value was 1.5 meq/100 g, it ranged from 0.34-3.4±0.78 mg/kg with a high CV of 53%. The values of exchangeable Ca were moderately variable (19%) and medium rating, except about 13.3% of the area that was low, this means that no part of the farm had high value of exchangeable Ca. The mean value was 2.20 meq/100g, it ranged from 1.0-2.7±0.42meq/100g. Mean CEC value was 12.8meq/100g, the values varied from 10.4-15.0±1.6meq/100g and a low CV of 11.4%. Al 3+ values ranged from 0.5-1.81±0.36 meq/100g with CV of 33% whereas, H+ had a mean value of 0.86 meq/100g and ranged from 0.02-1.40±0.41 with a CV of 47%. The EC mean value was 2.9ms/cm, it varied between 1.0-8.0±2.1 ms/cm and a high CV of 60%. The percentage base saturation was generally low, the values ranged from 16.89-37.12 with a mean of 26.2±4.22 and CV of 37.12%.

Table 3: Detrimental heavy metals and micro-nutrient contents of the farm.


 
Distribution of micro-nutrients
 
The micro-nutrients exhibited low and high spatial variability (Table 3). The nature of the spatial variability observed, justifies the adoption of site-specific nutrient management to ensure balanced nutrient supply. Mean Cu content value was 0.32 mg/kg, the values ranged between 0-0.17±0.17 mg/kg and CV of 53.8%. Manganese ranged from 0.68-3.40±0.09 mg/kg with a mean value of 1.25 mg/kg and a low CV of 0.09%. Nickel had a mean value of 0.71 mg/kg, the values ranged from 0.58-0.88±0.58 mg/kg with a CV of 12.1%. The Mo values ranged from 0-1.74± mg/kg with a mean of 1.14 mg/kg and a high CV of 40.8%. Whereas, Fe had a high CV of 60.5% with a mean value of 5.64mg/kg that ranged from 2.80-9.15±2.15 mg/kg. Chlorine had a mean value of 2.52 mg/kg and ranged from 2.47-2.61±0.45 mg/kg with a low CV of 1.78% while, Zn had a high CV value of 38.9% with a mean of 2.53 mg/kg and the values ranged from 1.02-3.374±0.91 mg/kg.
 
Detrimental heavy metals
 
Heavy metals were found in the farm (Table 3), the mean value of Se was 0.121 mg/kg with a high CV of 37.5%, the values ranged from 0.046-0.205±0.44 mg/kg. Cadmium was moderately variable (23.7%), the values ranged from 6.59-14.7±2.05 mg/kg with a mean of 8.64 mg/kg whereas, Pb was highly variable (54.2%) with a mean value of 0.05 mg/kg while the values ranged from 0-0.8±0.02 mg/kg. The mean value of As was 0.120 mg/kg with a CV value of 14.8%, the range was 0.111-0.166 0.01 mg/kg whereas, Cr had a mean value of 38.4 mg/kg with CV value of 11.7%, the values ranged from 27.6-44.2±4.5 mg/kg. Mercury had a mean value of 4.31 mg/kg, the range was between 3.03-6.06±0.97 mg/kg with a moderate CV value of 22.5%.
 
Correlation
 
All the basic cations were negatively and slightly correlated with soil pH (Table 4a). However, Na was moderately correlated with K. Table 4b showed that electrical conductivity and K were strongly and positively correlated (r=0.69) whereas, K and Na were moderately correlated (r=0.5). There was positively and strongly significant correlation between Na and P (r=0.6) and K and P (r=0.61) (Table 4c).

Table 4a: Correlation between pH and basic cations.



Table 4b: Correlation between electrical conductivity and basic cations.



Table 4c: Correlation between soil organic matter and major elements.


 
Soil evaluation factor of the farm
 
Table 5 presented soil fertility index (SFI) and Soil evaluation factor (SEF) of the farm. Nutrient management zone (NMZ) one, had the highest values of both the SFI and SEF followed NMZ 2 and 3 respectively.

Table 5: Soil fertility index soil evaluation factor rating and the management zones.


 
Categorization of the farm into management zones
 
Fig 1 and 2 showed both the soil organic matter and total nitrogen management zone of the farm. Larger proportions of the farm falls into the low soil organic matter and total nitrogen management zone while the smaller areas were found to be moderate and high. This indicates that the farm has low level of soil fertility.

Fig 1: Map showing the three management for soil organic matter.



Fig 2: Map showing different nutrient management zones for nitrogen.


       
The high sand content of the farm could be linked to the ploughing and consequent exposure of the surface soil to harsh climatic condition that led to continuous leaching of the colliodal particles (Amonmide et al., 2019). The pH values were strongly acidic which could be due to the use of inorganic fertilizers, the optimal pH levels ranges from 6.0-7.0. The acidic condition definitely could translate to low nutrient availability (Shaaban, 2024). To sustain good yield of crops in the farm, appropriate soil pH is relevant in view of its effect on nutrient availability and mobility as well as the microbial community that will decompose the organic matters in the soil (Shaaban, 2024). This is paramount for fertilizer programming for the newly established farm.   
       
The values of EC for crop production ranges from 0.8 to 1.8 ds/m and according to Okoror and Amanze (2024), it should not be above 2.5 ds/m. But in this situation of the farm, about 73% falls within the range, whereas the remaining 27% of the area had higher EC. As has been reported, EC value of loamy sand tends to range from 0-1.2 dS/m, this is applicable in this farm with similar soil texture (Okoror and Amanze, 2024). Sampling points with the highest soil organic carbon also had the highest value of EC; indicating that an increase in organic matter has a positive influence on soil nutrient availability for crop as it had higher EC (Yang et al., 2024). A CEC value below 10 cmol/kg will result to severe yield reduction as nutrient availability will be low and it is an important soil property that influences response to fertilizer (Yang et al., 2024). Danindra et al., (2022), observed that soil with high concentrations of ECEC but dominated by Al, H (low base saturation), will contain low level of soil fertility, that was the case in this farm where Al and H were higher. Percentage base saturation (BS) is another important soil quality indicator and it is the proportion of the CEC that is occupied by basic cations (Ćirić et al., 2023). Therefore, the low percentage base saturation indicated that the farm generally will not be fertile as it has acidic cations and Al3+. As the soil contain lower BS, basic cations (Ca2+, Mg2+, Na+ and K+) will be deficient in the soil (Leticia et al., 2017). Soil fertility parameters were spatially distributed and the micro variability could be as a result of the influence of management practices. The micro variation could be influence by management practices in the farm. Available P has mean value of 10.4 mg/kg, this was moderately low and this could be as a result of the elevated soil pH level (pH<5.0) that probably reduced phosphorus availability as P is fixed in acidic soils (Bastin et al., 2025 and Nwawuike, 2023).
       
The level of all the micro-nutrients measured were higher with reference to their critical levels (Mn =1.0 mg/kg, Cu = 0.2 mg/kg, Zn = 0.5 mg/kg and Fe = 4.5 mg/kg) (Ibia, 2012). The available Mn of the farm was therefore high given the fact that all the values recorded were above 1.00 mg/kg. The value within 1 mg/kg and higher but above 15 mg/kg could be harmful to crop (Ojobor and Aimufia, 2022). Similarly, Zn level within 4.5 mg/kg values are suitable for cropping whereas, if it is higher than 10 mg/kg, the crops would be at risk. Iron concentration was generally higher than other micronutrients evaluated. The high concentration of Fe could be due to abundance of sesquioxides (Ibia, 2012). This could also be linked to soils formed from basement complex rocks that contain high Fe compounds (Ojobor and Aimufia, 2022). Also, excessive use of mineral fertilizer most especially P fertilizers, could lead to deficiency of micro-nutrients (Nwawuike, 2023).

CONCLUSION

It can be concluded that due to the acidic nature of the soil, non-acid forming fertilizers should be applied at recommended rates to boost crop yield and should be applied according to the nutrient needs of the crops.

ACKNOWLEDGEMENT

The present study was supported by all the Authors.
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of us the authors and not the views of our affiliated institution. We are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
 
Informed consent
 
No animal was used in this experiment.

CONFLICT OF INTEREST

There are no conflicts of interest regarding the publication of this article. No funding or sponsorship.

REFERENCES


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  6. Danindra, D., Setiawan, R.P.A., Desria, l., Solahudin, M., Astika, I.W. and Widodo, S. (2022). Mapping of Soil EC in Relation with Selected Chemical Properties of Soil. IOP Conf. Series: Earth and Environmental Science. pp: 1-8.

  7. Delsouz, K.B., Honarjoo, N., Davatgar, N., Jalalian, A. and Torabi, G.H. (2017). Assessment of two soil fertility indexes to evaluate paddy fields for rice cultivation. Sustainability. 9(8): 1299. https://doi.org/10.3390/su9081299.

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    Full Research Article

    Appraisal of Soil Fertility: A Case Study of Okpare-olomu Farm Settlement in Ughelli South Local Government Area, Delta State

    S
    S.A. Ojobor1,*
    https://orcid.org/0000/0002-6835-6797
    G
    G.O. Okogu1
    O
    O.F. Elike2
    1Department of Agronomy, Faculty of Agriculture, Delta State University Abraka, Nigeria.
    2Department of Soil and Land Resource Management, Faculty of Agriculture, Dennis Osadebay University, Asaba, Nigeria.

    ABSTRACT

    Background: Fertilizer application without soil test has resulted to nutrient imbalance and toxicity leading to widespread yield depletion. Appraisal of soil fertility status of Timpher Farms Limited in Okpare-Olomu, Ughelli-south local government area of Delta State.

    Methods: Soil samples and their coordinates were taken and soil quality indicators were analyse using standard procedures. Soil fertility index and Soil evaluation factor were calculated and used to delineate the arable farm area into nutrient management zones. Data were analyzed with descriptive statistics and correlation coefficient was used to establish the relationship among soil variables.

    Result: The soil is loamy sand, strongly acidic with an average soil organic matter while total nitrogen was low. Available P was moderate, exchangeable bases were low except for Ca that was moderate. Base saturation was low whereas CEC was moderate but dominated by non-basic cations. The micronutrients were adequate for crop production. Larger proportions of the farm falls within the low soil organic matter and total nitrogen management zones; indicating that the farm had low soil fertility.

    INTRODUCTION

    In the current unprecedented food challenges, soil fertility synthesis could be a potent tool for improving crop production (Dandasena et al., 2024 and Sachan et al., 2022). Nutrient management practices adopted to produce economic yield and at the same time maintain minimal nutrient leakage can only be achieved through timely evaluation of soil fertility (Dandasena et al., 2024 and Sachan et al., 2022). Soil quality indicators that determined the fertility and are evaluated after analysis. Soil fertility evaluation measures the availability of plant nutrients and also estimate the capacity of the soil to supply crop the elements (Ayodele et al., 2019 and Ojobor et al., 2021). Up-to-date information on soil characteristics is essential in sustaining production of crops. Lack of basic information on the levels and management of soil properties has led to continued yield decline (Nwawuike, 2023 and Iraiyanban et al., 2025). The limited information on site-specific fertilizer amendment arouses the need for assessing the nutrient status of soil. This will aid in developing appropriate management policy as the soil resources (Ayodele et al., 2019). Cropping sustainability requires frequent evaluation of soil quality as different land uses change the properties.
           
    Soil is indispensable natural resource that plays a relevant role in improving crop production however, inadequate information about the potential uses are lacking. Soil fertility assessment will provide useful data on the nutrient and their distribution that are crucial for implementation of sustainable management (Ofem et al., 2023). Understanding soil fertility variation could be tools in decision making (Okebalama et al., 2024). Therefore, background information about the soil fertility is required before soil amendment (Delsouz et al., 2017). A basic aspect of sustainable crop production is monitoring of soil fertility (Dandasena et al., 2024) and this helps to provide key information on how to improve the soil because, limiting factors will be identify that will enable management guideline implementations (Hadole et al., 2019 and Iraiyanban et al., 2025).
           
    Okpare-Olomu is a notable farming community in Ughelli south local government area under Delta central agricultural zone. The community is predominantly known for cultivation crops and houses different farm settlements. Timpher Farms Limited (about 40 hectares) is one of such that was newly established. For proper planning for various uses, there is need to critically identify the limiting nutrients, this will guide the implementation of management options for the area.  On this premise, the study tends to investigate the nutrient status and create nutrient management zones for the farm.

    MATERIALS AND METHODS

    The study area
     
    The study was conducted at Okpare-Olomu in Ughelli North Local Government Area, Delta state. It is situated between latitude N 502515611 and Longitude E 505415011, 21.1 meters elevation above sea level and falls within the rainforest agro-ecological zone of Nigeria. The land is relatively flat with different areas planted to Oil palm, Cassava, sparse distribution of Maize, several grasses and shrubs.
     
    Soil sampling, handling and laboratory analyses 
     
    Soil samples were collected with an auger at 0-15 cm depth, air dried and taken to the laboratory for analysis. Standard laboratory methods were determine the soil properties. Sampling points and their coordinates were taken.
     
    Soil fertility index and soil evaluation factor (SEF)
     
    The SFI and SEF were examined and used to categorize the farm into nutrient management zones.
     
    Data analysis
     
    All data generated were subjected to simple descriptive statistics while correlation analysis was used to show their relationships.
     

    RESULTS AND DISCUSSION

    Particle size distribution, pH, organic matter and macronutrients of the farm
     
    The soil particle size fractions indicate mean clay content to be 9.1%, silt was 8.7% and sand was 82%. The values ranged from 7.0-13±1.9% with coefficient of variation (CV) of 2.1% clay, 5.0-13±2.9% with CV of 30% silt and 78-86±2.4 with CV of 2.9% sand, indicating dominance of sand with low spatial heterogeneity (Table 1). Considering the textural class of the area, the soils are relatively not compacted.

    Table 1: Particle size distribution.


     
    pH, organic matter and macro nutrients of the farm
     
    pH
     
    The farm area fell within the strongly acidic category with a mean value of 4.9, the range was 4.2-5.4±0.3 with CV of 6.2. The pH of the study area is not considered suitable for most crops, tough the variability was low (Table 3).

    Organic matter
     
    The mean soil organic matter was 1.8% and the range was 0.89-3.58±0.70% with CV of 41.5% (Table 2). About 60% of the study area was low, 26.7% was moderate whereas, only 13.3% of the total area of the farm was high, showing that the study area was highly variable in organic matter content.

    Table 2: Particle size distribution, pH, organic matter and macro nutrients of the farm.


           
    Average TN was 0.15%, the values ranged between 0.11-0.23±0.04% with a CV of 23%. Higher per cent (60%) of the farm was low, only 26.7 and 13.3% were medium and high, respectively. The mean available P was 10.4 mg/kg, it ranged from 7.5-14.9±2.1 mg/kg with CV of 19.7% (Table 3). About 46.7% of the farm area was low whereas, 53.3% were moderate that is, no area was found to be high. All parts of the farm had low Na and had similar value of 0.08 meq/100 g in the entire farm. Potassium was also generally low, only less than 10% of the land was high in available K. The mean value was 0.08 meq/100 g, it ranged from 0.03-0.39±0.08 meq/100 g with a very low CV of 0.06%. Mean Mg value was 1.5 meq/100 g, it ranged from 0.34-3.4±0.78 mg/kg with a high CV of 53%. The values of exchangeable Ca were moderately variable (19%) and medium rating, except about 13.3% of the area that was low, this means that no part of the farm had high value of exchangeable Ca. The mean value was 2.20 meq/100g, it ranged from 1.0-2.7±0.42meq/100g. Mean CEC value was 12.8meq/100g, the values varied from 10.4-15.0±1.6meq/100g and a low CV of 11.4%. Al 3+ values ranged from 0.5-1.81±0.36 meq/100g with CV of 33% whereas, H+ had a mean value of 0.86 meq/100g and ranged from 0.02-1.40±0.41 with a CV of 47%. The EC mean value was 2.9ms/cm, it varied between 1.0-8.0±2.1 ms/cm and a high CV of 60%. The percentage base saturation was generally low, the values ranged from 16.89-37.12 with a mean of 26.2±4.22 and CV of 37.12%.

    Table 3: Detrimental heavy metals and micro-nutrient contents of the farm.


     
    Distribution of micro-nutrients
     
    The micro-nutrients exhibited low and high spatial variability (Table 3). The nature of the spatial variability observed, justifies the adoption of site-specific nutrient management to ensure balanced nutrient supply. Mean Cu content value was 0.32 mg/kg, the values ranged between 0-0.17±0.17 mg/kg and CV of 53.8%. Manganese ranged from 0.68-3.40±0.09 mg/kg with a mean value of 1.25 mg/kg and a low CV of 0.09%. Nickel had a mean value of 0.71 mg/kg, the values ranged from 0.58-0.88±0.58 mg/kg with a CV of 12.1%. The Mo values ranged from 0-1.74± mg/kg with a mean of 1.14 mg/kg and a high CV of 40.8%. Whereas, Fe had a high CV of 60.5% with a mean value of 5.64mg/kg that ranged from 2.80-9.15±2.15 mg/kg. Chlorine had a mean value of 2.52 mg/kg and ranged from 2.47-2.61±0.45 mg/kg with a low CV of 1.78% while, Zn had a high CV value of 38.9% with a mean of 2.53 mg/kg and the values ranged from 1.02-3.374±0.91 mg/kg.
     
    Detrimental heavy metals
     
    Heavy metals were found in the farm (Table 3), the mean value of Se was 0.121 mg/kg with a high CV of 37.5%, the values ranged from 0.046-0.205±0.44 mg/kg. Cadmium was moderately variable (23.7%), the values ranged from 6.59-14.7±2.05 mg/kg with a mean of 8.64 mg/kg whereas, Pb was highly variable (54.2%) with a mean value of 0.05 mg/kg while the values ranged from 0-0.8±0.02 mg/kg. The mean value of As was 0.120 mg/kg with a CV value of 14.8%, the range was 0.111-0.166 0.01 mg/kg whereas, Cr had a mean value of 38.4 mg/kg with CV value of 11.7%, the values ranged from 27.6-44.2±4.5 mg/kg. Mercury had a mean value of 4.31 mg/kg, the range was between 3.03-6.06±0.97 mg/kg with a moderate CV value of 22.5%.
     
    Correlation
     
    All the basic cations were negatively and slightly correlated with soil pH (Table 4a). However, Na was moderately correlated with K. Table 4b showed that electrical conductivity and K were strongly and positively correlated (r=0.69) whereas, K and Na were moderately correlated (r=0.5). There was positively and strongly significant correlation between Na and P (r=0.6) and K and P (r=0.61) (Table 4c).

    Table 4a: Correlation between pH and basic cations.



    Table 4b: Correlation between electrical conductivity and basic cations.



    Table 4c: Correlation between soil organic matter and major elements.


     
    Soil evaluation factor of the farm
     
    Table 5 presented soil fertility index (SFI) and Soil evaluation factor (SEF) of the farm. Nutrient management zone (NMZ) one, had the highest values of both the SFI and SEF followed NMZ 2 and 3 respectively.

    Table 5: Soil fertility index soil evaluation factor rating and the management zones.


     
    Categorization of the farm into management zones
     
    Fig 1 and 2 showed both the soil organic matter and total nitrogen management zone of the farm. Larger proportions of the farm falls into the low soil organic matter and total nitrogen management zone while the smaller areas were found to be moderate and high. This indicates that the farm has low level of soil fertility.

    Fig 1: Map showing the three management for soil organic matter.



    Fig 2: Map showing different nutrient management zones for nitrogen.


           
    The high sand content of the farm could be linked to the ploughing and consequent exposure of the surface soil to harsh climatic condition that led to continuous leaching of the colliodal particles (Amonmide et al., 2019). The pH values were strongly acidic which could be due to the use of inorganic fertilizers, the optimal pH levels ranges from 6.0-7.0. The acidic condition definitely could translate to low nutrient availability (Shaaban, 2024). To sustain good yield of crops in the farm, appropriate soil pH is relevant in view of its effect on nutrient availability and mobility as well as the microbial community that will decompose the organic matters in the soil (Shaaban, 2024). This is paramount for fertilizer programming for the newly established farm.   
           
    The values of EC for crop production ranges from 0.8 to 1.8 ds/m and according to Okoror and Amanze (2024), it should not be above 2.5 ds/m. But in this situation of the farm, about 73% falls within the range, whereas the remaining 27% of the area had higher EC. As has been reported, EC value of loamy sand tends to range from 0-1.2 dS/m, this is applicable in this farm with similar soil texture (Okoror and Amanze, 2024). Sampling points with the highest soil organic carbon also had the highest value of EC; indicating that an increase in organic matter has a positive influence on soil nutrient availability for crop as it had higher EC (Yang et al., 2024). A CEC value below 10 cmol/kg will result to severe yield reduction as nutrient availability will be low and it is an important soil property that influences response to fertilizer (Yang et al., 2024). Danindra et al., (2022), observed that soil with high concentrations of ECEC but dominated by Al, H (low base saturation), will contain low level of soil fertility, that was the case in this farm where Al and H were higher. Percentage base saturation (BS) is another important soil quality indicator and it is the proportion of the CEC that is occupied by basic cations (Ćirić et al., 2023). Therefore, the low percentage base saturation indicated that the farm generally will not be fertile as it has acidic cations and Al3+. As the soil contain lower BS, basic cations (Ca2+, Mg2+, Na+ and K+) will be deficient in the soil (Leticia et al., 2017). Soil fertility parameters were spatially distributed and the micro variability could be as a result of the influence of management practices. The micro variation could be influence by management practices in the farm. Available P has mean value of 10.4 mg/kg, this was moderately low and this could be as a result of the elevated soil pH level (pH<5.0) that probably reduced phosphorus availability as P is fixed in acidic soils (Bastin et al., 2025 and Nwawuike, 2023).
           
    The level of all the micro-nutrients measured were higher with reference to their critical levels (Mn =1.0 mg/kg, Cu = 0.2 mg/kg, Zn = 0.5 mg/kg and Fe = 4.5 mg/kg) (Ibia, 2012). The available Mn of the farm was therefore high given the fact that all the values recorded were above 1.00 mg/kg. The value within 1 mg/kg and higher but above 15 mg/kg could be harmful to crop (Ojobor and Aimufia, 2022). Similarly, Zn level within 4.5 mg/kg values are suitable for cropping whereas, if it is higher than 10 mg/kg, the crops would be at risk. Iron concentration was generally higher than other micronutrients evaluated. The high concentration of Fe could be due to abundance of sesquioxides (Ibia, 2012). This could also be linked to soils formed from basement complex rocks that contain high Fe compounds (Ojobor and Aimufia, 2022). Also, excessive use of mineral fertilizer most especially P fertilizers, could lead to deficiency of micro-nutrients (Nwawuike, 2023).

    CONCLUSION

    It can be concluded that due to the acidic nature of the soil, non-acid forming fertilizers should be applied at recommended rates to boost crop yield and should be applied according to the nutrient needs of the crops.

    ACKNOWLEDGEMENT

    The present study was supported by all the Authors.
     
    Disclaimers
     
    The views and conclusions expressed in this article are solely those of us the authors and not the views of our affiliated institution. We are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
     
    Informed consent
     
    No animal was used in this experiment.

    CONFLICT OF INTEREST

    There are no conflicts of interest regarding the publication of this article. No funding or sponsorship.

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