In the recent past, productivity of agricultural soils worldwide was on the decline. These declining trends across the world were attributed to ever growing population, lowered incomes of populous nations, discovery of new uses such as bio-fuels from agricultural products, as well as weather-based abnormalities associated with climate change often culminating in decline in rainfall with attendance food shortages. 

The continued decline in soil productivity could be checked by effective monitoring of the soil health. Characterization is key to soil productivity and determines options for soil management. [1]

Classifications systematically arrange soils into groups or categories base on   distinguishing characteristics as well as criteria that dictate choices in use. Such system fosters global communication about soils; soil scientists and people saddled with land management and conservation of soil resources. The management option that will guarantee high soil productivity principally depends on the nature and properties of that soil.   

Land evaluation is a systematic process of identifying and measuring land qualities and assessing them for various kinds of uses. In agricultural land use unlike other uses, is discriminatory. It is a fact that not all soils can be used for agricultural purpose and not all crops can be successfully grown on a particular soil type. It is often that a soil type suitable for a particular crop may not be suitable  for  another  crop  because  crops  differ  in  their requirements. These requirements must be understood within the context of limitations imposed by land and other features which do not form part of the soil but may have a significant influence on use that can be made of the land [3]. Inadequate information on the status of agricultural lands can lead to misuse, mismanagement which will eventually manifest in the form of land degradation.

Maize is the most stable food in most households; the medicinal roles of Ginger cannot be over emphasized while Pepper remains one of the leading spices in local and continental meals beside other vital roles on the nutritive scales of many nations, Nigeria inclusive. They are cultivated in large quantities in and on lands adjoining the Joseph Saawuan Tarka University indiscriminately with little or no regards as to which soil requirements the crops need for their optimum production. This study was therefore set out to characterize, classify and determine the suitability of these soils for ginger, pepper and maize cultivation.

LOCATION

The study area lies directly behind the University Clinic; {Latitudes 7^o47’4’’N; Longitude 8^O37’20’’E; 89-109masl and Latitude 7^o47’20’’N, Longitude 8^o 37’28’’E, 94-103masl and covered 30,000m² (3ha).

Field Work

Profiles’ location, slope and height above sea level were taken by use of Global Positioning System (GPS) -Altimeter. The site was subjected to detailed soil survey through conventional grid method. Three profile pits were sunk to 2.0m depth or impenetrable layer or whichever is shallower and morphologically characterized using the pattern outlined in the soil survey manual [3,4]. Soil samples collected from genetic horizons were package in properly labeled sample bags and taken to the Advanced Soil Science Laboratory JOSTUM for the physical and chemical analysis. 

Laboratory Work 

Soil samples were air dried and made to pass through a 2mm sieve. They were then subjected to laboratory analysis using the Manual of Selected Methods of Plants and Soil Analysis, IITA. 

Land Suitability Evaluation 

It was done using the  conventional parametric method [5]. Pedons were placed in suitability classes by matching their characteristic means (except morphological parameters) with established    requirements for each crop (Table 1). The final (aggregate) suitability class indicates the most limiting characteristics or parameters.

Climatic Mean Data (2020 and 2021) 

That were obtained from NIMET weather station localized in the Department of Soil Science, Joseph Saawuan Tarka University, Makurdi (NIMET-JOSTUM).

Physical Properties

Results in Table 1 show the low-lying soils with a slope, 0-3%; profiles depths, 130-151cm and well to imperfectly drained. Soils varied from very dark reddish grey (2.5YR 4/3) or reddish brown (2.5 YR 3/1) to reddish yellow (5YR6/8) surfaces while the subsurfaces were grayish (10YR5/1), imprints of gleization with reddish yellow (7.5 YR 6/6) to red (10 YR 5/8) mottles, attributed to imperfect drainage condition (redoxmorphism). Abagyeh et al. [1] attributed mottling to oxidation-reduction cycles as groundwater table fluctuates. Underlying the sandy loam is sandy clay loam with weak Fine crumbs to moderately sub angular blocky structures which make the sites suitable for agriculture production. Occurrences of higher clay contents in the subsurface horizons of profiles is attributed to elluviation from epipedons and its illuvation in the subsoils; indicating that the soils were well developed. Silt content shows uniform distribution pattern in all profiles. Higher sand percentages were observed in the epipedons of all profiles. The finer silt and clay fractions were iluviated in to the lower horizons at the detriment of the sand fraction, hence sandy loam surfaces and sandy clay loam or clayed subsurfaces. Abagyeh et al [6] reported that parent material’s grain sizes are the main determinant of the soil texture. Bulk densities (1.19-1.38gcm^-3) indicate that the soils were not compacted and therefore suitable for agricultural purposes.

Chemical Properties

Soil reaction was slightly acidic to moderately acidic (pH 6.1- 6.79), these values are within the pH requirement for most available nutrients up take by arable. The higher OC in the surface (0.34%) than subsurfaces (0.20%) may be attributed to addition of farmyard manures and plant residues to the surface horizons [6]. Nitrogen values follow the trend in OC (0.088% to 0.022%) in all soils. Total nitrogen is mobile in soils as a result, its losses through various mechanism like NH₃ volatilization, chemical and microbial fixation, and leaching and runoff. Thus, results in residual/available nitrogen becoming poor in soils [6]. The low values of phosphorus (5.03-5.82mgkg^-1), too low to sustain productive soils were due to low cation exchange capacity (CEC) and clay content in conformity with Abagyeh et al. (2019) on Lower Benue River Basin soils. Exchangeable bases occurred in the order of Ca (2.63) > Mg(1.85) > K(0.31) > Na(0.25cmolkg^-1) on the exchange complex of pedon 1 and similar trend in pedons 11 and 111 and were rated medium to very low in all the profiles. Kang attributed the trend to the nature of the underlying materials, intensity of weathering and leaching, low activity clay content, very low organic matter content and the lateral translocation of bases according to. It was clear that Mg was present in lower amount than Ca²⁺ because of its higher mobility. These conform to findings of Abagyeh et al [6]. Higher CEC values were found mostly in horizons with higher clay contents. Similar trends were observed in some Nigerian Southern Guinea Savanna soils. In all pedons, the epipedons possessed higher base saturation than the subsurface horizons which was attributed to the return of these cations to the surface from the subsoils by the pumping effect of vegetation or through capillarity. [7] 

Table 1: Land and Soil Requirements for Suitability Rating of ginger(G), Pepper(P) and Maize(M)

Sources: USDA, 2003 (modified) and Annal of Botany (2001)., LEGEND: FO =No Flooding, F1= Seasonal Flooding, MR= Flooding Rare, WD = Well Drained, IWD= Imperfectly Drained, F1 = Rarely Drained, F0 = Poorly Drained, VPD= Very Poorly Drained, C= Clay, CL= Clay Loam, SCL= Sandy Clay Loam, SC= Sandy Clay;SBK =Sub Angular Blocky, S11 = Very Highly Suitable, S12  = Highly Suitable, S2 = Moderately Suitable, S3 = Marginally Suitable, N1 = Currently Not Suitable, N2 = Permanently Not Suitable; G- Ginger, P-Pepper, Maize,   Soil Phy. Props.= Soil Physical Properties, d/m –day/month

Table 2: Selected Soil Properties at Soil Science Departmental Farm, Behind University Clinic of Joseph Saawuan Tarka University, Makurdi

LEGEND: CF = Coarse Fragments, BD = Bulk Density, Dz = Designation Typic Paleustalf (Clayiec Luvisols. Rhodic, Kandic). {Latitudes 7o47’4’’N; Longitude 8o37’20’’E; 103.5mamsl} Typic Paleustalf (Clayiec Luvisols. Rhodic, Kandic). {Latitudes 7o47’4’’N; Longitude 8o37’20’’E; 103.5mamsl} Kanhaplic Rhodustalfs (Kandic Luvisols. Rhodic) {Latitude 7o47’19’’N, Longitude 8o 37’24’’; 97mamsl} Kanhaplic Rhodustalfs (Kandic Luvisols. Rhodic). {Latitude 7o47’20’’, Longitude 8o 37’28’’; 98.5mamsl}

Table 3: Land and Soil Characteristics Used for Soil Suitability Rating for ginger(G), Pepper(P) and Maize(M) at Soil Science Departmental Farms JOSTUM

Table 3: Continue

Key: L/S Xtics. = Land and Soil Characteristics; ⃰Climate = NIMET JOSTUM; Crops: G = Ginger, M = Maize P = Pepper

The soils were classified ino Kanhaplic Rhodustalfs (Kandic Luvisols, Eutric; Arenic Luvisols, Kandic Rhodic) for pedons 1 and 11 and  Typic Paleustalf (Clayeic luvisol, Gleiyeic, Kandic) for pedon 111. 

Land Suitability Evaluation

The results of matching data of land parameters with the requirements of

• Ginger(G), 

• Pepper(P) and 

• Maize(M) 

presented in Table 3 showed that Pedon 1 was highly suitable (S1) for pepper cultivation in maximum temperature, annual rainfall and soil drainage, texture, effective depth and elevation. It was however currently not suitable (N1) in its OC content. 

Pedon11 was highly suitable in all climatic and topographic as well as flooding (wetness), structure and effective soil depth (soil physical properties) and soil pH components. The soil’s texture reduced its suitability to moderately suitable (S2) and base saturation to marginally suitable (S3) subclasses. Organic carbon and available phosphorus further lowered the soil’s suitability to currently not suitable (N1) subclass.

Pedon 111 was very highly suitable (S1₁) for maize cultivation in rainfall, length of rainy season, topographic slope, flooding, coarse fragment, base saturation, and in soil water pH. The soil was highly suitable (S1₂) for maize cultivation in relative humidity and soil textural configuration. Relative humidity and extractable K limited the soil’s suitability to cultivate maize to moderately suitable (S2); CEC and Availble P further reduced the suitability to marginally suitable (S3). The least limiting factor(s) Organic matter (TN) worsen the soil’s suitability for maize production as it was reduced to currently not suitable (N1) subclass.

On aggregate, land elevation (97m) and OC (0.25%) cumulatively could not substantially reduced pedon 1 suitability as the land is highly suitable (S1) for pepper cultivation. Major limitations of Pedon 11 were climate (c), wetness (w) and soil physical properties (s) and OC lowered it suitability for ginger cultivation from very highly suitable (S1₁) to highly suitable (S1₂cws). Pedon 111 on the other hand has temperatures (c), CEC, OC/TN and extractable K (f) as major limitations and was rated moderately suitable (S2cf) for maize production.

Soil Management

Mineral fertilizers application will correct specific nutrient deficiencies and boast soil fertility in general.

Organic matter incooperation, will remedy textural deficiency and create structural stability with enhance general soil fertility. Crops that can tolerate climatic and topographic conditions prevalent in this environment may be planted

1. Abagyeh, S.O.I., Forn et al. "Characterization, classification and management of integrated landscapes in the Middle Benue Valley of Benue State." Nigerian Journal of Soil Science, vol. 27, 2017, pp. 267–281.

2. FAO. Crop Calendars. Plant Production and Protection Paper 12, FAO, 1978, Rome, 124 p.
3. Soil Survey Staff. Keys to Soil Taxonomy. 11th ed., USDA Natural Resources Conservation Service, 2010, Washington, DC, 126 p.
4. Gutherie, R.L., and I. Witty. "New designation for soil horizons and layers and the new soil survey manual." Soil Science Society of America Journal, vol. 46, 1982, pp. 443–444.
5. FAO. A Framework for Land Evaluation. FAO Soils Bulletin 32, FAO, 1976, Rome, 87 p.
6. Abagyeh, S.O.I., Forn et al. "Characterization, classification and management of some soils in Ujam District of Makurdi, Benue State." European Journal of Agriculture and Forestry Research, vol. 7, no. 4, 2019, pp. 14–22.

No funding sources

The study was approved by the Joseph Saawuan Tarka University, Makurdi, Nigeria.

1. Abagyeh, S. O. L., Wuese, S. T., & Ezenwa, M. I. S. (2017). Characterisation, Classification and Management of Integrated Landscapes in the Middle Benue Valley of Benue State. Nigerian Journal of Soil Science, 27, 267-281.

2. FAO. (1978). Crop calendars.Plant Production and Protection Paper 12. FAO, Rome. 124 p.

3. Soil Survey Staff, (2010). Key to Soil Taxonomy, 11 Edition. Basic system of Soil Classification for Making and Interpreting Soil Survey, National Reserve Conservation Services, Agricultural Dept. Soil Survey Division. Washington DC USA. 126p.

4. IITA. (1979). Manual of Selected Methods for Plants and Soil Analysis. Manual Series No.1.

5. Abagyeh, S. O. I., Anande A. P. &Abagyeh, I. J. (2019). Characterization, Classification and Management of Some Soils in Ujam District of Makurdi, Benue State. European Journal of Agriculture and Forestry Research. 7(4), pp14-22.

6. Abagyeh, S. O. I. (2004). Classification of Soils as Related to the Performance of Orange (Citrus Sinensis) and Mango (Mangifera Indica) in the Nigerian Guinea Savanna. Department of Soil Science, School of Agriculture and Agricultural Technology. Federal University of Technology Minna. M.Tech. Thesis.