Prof Joshua Ogunwole (Katsina, Nigeria)

Professor of Applied Soil Physics, Department of Crop Production and Protection

Gunnar Kirchhof

Recent Publications

Joshua O. Ogunwole, Luis C. Timm, Evelyn O. Obidike-Ugwu, Donald M. Gabriels, 2014. State-space estimation of soil organic carbon stock. International Agrophysics, 28, 185-194.

Understanding soil spatial variability and identifying soil parameters most determinant to soil organic carbon stock is pivotal to precision in ecological modelling, prediction, estimation and management of soil within a landscape. This study investigates and describes field soil variability and its structural pattern for agricultural management decisions. The main aim was to relate variation in soil organic carbon stock to soil properties and to estimate soil organic carbon stock from the soil properties. A transect sampling of 100 points at 3 m intervals was carried out. Soils were sampled and analyzed for soil organic carbon and other selected soil properties along with determination of dry aggregate and water-stable aggregate fractions. Principal component analysis, geostatistics, and state-space analysis were conducted on the analyzed soil properties. The first three principal components explained 53.2% of the total variation; Principal Component 1 was dominated by soil exchange complex and dry sieved macroaggregates clusters. Exponential semivariogram model described the structure of soil organic carbon stock with a strong dependence indicating that soil organic carbon values were correlated up to 10.8m.Neighbouring values of soil organic carbon stock, all waterstable aggregate fractions, and dithionite and pyrophosphate iron gave reliable estimate of soil organic carbon stock by state-space.

Ogunwole, J.O., E.O. Obidike, L.C. Timm, A.C. Odunze and D. Gabriels. Assessment of spatial distribution of selected soil properties using geo-spatial statistical tools. Communications in Soil Science and Plant Analysis (In Press).

In order to gain additional knowledge and better understand forest soil management at small scale, geostatistical analytical tools were employed to examine the spatial distribution in dry aggregate mean weight diameter (MWD) and other selected soil properties and, to assess the possible relationships between MWD and the rest soil properties. Selected properties of forest soils collected along a 300-m transact in the Nimbia Forest Reserve of Nigeria exhibited moderate to high variability in distribution with sodium ion displaying the highest variability (CV, 91.2%) and principal component analysis revealed the exchange complex cluster as influencing total variation of field soil properties. The autocorrelation function showed significant spatial correlation from 1 lag in soil organic carbon up to 17 lags (51 m) in soil moisture content (?). The spherical and Gaussian semivariogram models described spatial structure of most soil properties however, for clay, CEC and SOC; exponential model analyzed their spatial dependence.

Lawal, H.M., J.O.Ogunwole, E.O. Uyovbisere 2012. Reciprocal relationship between aggregate stability and organic carbon characteristics in a forested ecosystem of northern Nigeria. Tropical and Subtropical Agro-ecosystems, 15: 481- 488.

Soil organic matter associated with different size aggregates differ in structure and function; therefore, play different roles in soil organic carbon (SOC) turnover. This study assessed the relationship between aggregate stability and soil organic carbon fractions in a forested soil. Aggregate stability characterized by mean weight diameter (MWD) was correlated with the various pools of SOC in a regression model. Mean weight diameter presented a 46% influence on total organic carbon while, total organic carbon accounts for 21.8% of aggregate stability. The unprotected and physically protected soil organic carbon did not significantly dictate stability of these soils. However, chemically protected & biochemically protected SOC influenced significantly, aggregate stability of these forested soils

Halilu, A.D., S.M. Misari, C.A. Echekwe, O. Alabi, I.U. Abubakar, M.K. Saleh, A.O. Adeyanju and J. Ogunwole, 2011. Survey and collection of Jatropha curcas L. in the northwestern Savannas of Nigeria. Biomass and Bioenergy, 35: 4145-4148.

The Existence and Distribution of Jatropha curcas L. germplasms in the Northwest zone of Nigeria is hereby reported with coordinates and point mapping. Fifty seven (57) accessions were collected from the seven States of the zone which spans across the Sahel, Sudan and Guinea Savannas. The collection was made from 18th to 22nd of August 2009. A plantation was established from these collections and the seeds from 39 different provenances of the seven States were analyzed for their oil content. The mean oil content ranged from 20.29% to 61.83% (CV 29.11%). The 100-seed weight ranged from 28.558g to 80.046g. There was a positive correlation between 100 seed weight and oil content (r ¼ 0.235). The accessions from Kaduna State, spanning through the Sudan and Northern Guinea Savanna, had the highest mean oil content followed by those from Kano and Katsina States in the Sudan Savanna ecology. There were no significant differences ( p

Ogunwole J.O., E.N.O. Iwuafor, N.M. Eche, J. Diels 2010. Effect of organic and inorganic soil amendments on soil physical and chemical properties in a West African Savanna agroecosystem. Tropical and Subtropical Agro-ecosystems, 12: 247-255.

Long term agroecosystem productivity has stirred up the need to develop and implement nutrient management strategies that maintain and protect soil resources. In an attempt to address this, the current study involved the incorporation of residues of Centrosema pascorum, Lablab purpureus and Pakia biglobosa. In addition, an inorganic fertilizer amended soil and, a maize/lablab purpureus intercrop, along with the control (no amendment) was included. The treatments were replicated three times and the site had been under continuous cultivation for eight years in a Savanna Alfisol. Soil quality (physical and chemical) indicators were examined for treatments effects. Dry macroaggregate turnover increased by 7% under Centrosema pascorum amended soils. This same treatment had more water stable large microaggregates and a 40% increase in aggregated silt and clay content. Soil bulk density and saturated hydraulic conductivity reduced in nutrient management practices involving residue incorporation. However, soil organic carbon, total soil nitrogen, exchangeable Ca2+ and Mg2+ concentration were highest with soil receiving Centrosema pascorum. Crop residue management practices involving incorporation of Centrosema pascorum significantly improved soil physical and chemical properties of the study area

Oyinlola, E.Y., J.O. Ogunwole, I.Y. Amapu 2010. Response of sunflower (Helianthus annuus L.) to nitrogen application in a Savanna Alfisol. Helia 33 (Nr. 52): 115-126

Decline in crop yield has beed a major problem in Northern Guinea Savanna of Nigeria due to inherent low fertility status of the soils. Field experiments were conducted for two years (2003 & 2004) on an Alfisol of the Northern Guinea Savanna of Nigeria to determine the effect of N fertilizer on growth and yield parameters of sunflower. Six rates of nitrogen (0, 30, 60, 90, 120 & 150 kg N ha-1) were applied. Plant heights of 120 & 138 cm were obtained in 2003 and 2004 respectively, at 120 kg N ha-1. Application of N significantly increased seed and oil yields while excess N (150 kg N ha-1) reduced the contents of the two parameters. Optimum nitrogen requirement of sunflower obtained from this study is between 90 & 100 Kg N ha-1.

Lawal, H.M., J.O.Ogunwole, E.O. Uyovbisere 2009. Changes in soil aggregate stability and carbon sequestration mediated by land use practices in a degraded dry savanna Alfisol. Tropical and Subtropical Agro-ecosystems, 10: 423-429

Effects of land use practices on aggregate stability and fractions of soil organic carbon were investigated using physical fractionation procedure. Soils were sampled at three depths (0-5, 5-10 & 10-15 cm) under arable cropping, native vegetation and forest plantation. These soils were separated into aggregates to calculate mean weight diameter (MWD) and aggregate associated carbon. Results showed that MWD increased in soils under forest plantation by 61.4% relative to the soils under arable cropping practice. The macroaggregate fraction in the forested soils was 76.2% more than those soils under arable cropping. Chemically protected carbon was higher by 39% in soil under arable cropping compared to forested soil. Forest plantations therefore may have potential to increase the structural stability of soils and their resistance to soil erosion. Arable cropping seems to favour increasing carbon sequestration relative to native vegetation and Eucalyptus forested soils.

Ogunwole, J.O. 2008. Aggregate characteristics and organic carbon concentrations after 45 annual applications of manure and inorganic fertilizer. Biological Agriculture and Horticulture (Great Britain: AB Academic Press), 25(3): 223-233

Soil management practices that increase soil carbon sequestration can improve soil quality and reduce agricultural contribution to carbon dioxide emissions. The long term (45 years) effect of applications of manure (FYM) and inorganic (NPK) fertilizers on soil aggregate characteristics and soil organic carbon (SOC) concentration was studied in surface soils of a Typic Haplustalf, sandy loam. Soils from four treatments: inorganic fertilizer combined with farmyard manure (FYM +NPK), fertilizer only (NPK), farmyard manure only (FYM) and a control receiving neither NPK nor FYM were studied. Results indicate that long term application of manure with or without NPK improved aggregate stability by increasing mean weight diameter (MWD) of dry aggregate and fraction of dry aggregate > 2 mm. Higher values of MWD were also recorded in the water stable aggregate size distributions for soils amended with either FYM or NPK. Soils amended with FYM + NPK sequestered more SOC than all other treatments. There was a low but significant positive correlation between MWD of dry aggregates and SOC. Highest values of SOC were recorded in the > 2.0 mm dry aggregate is suggestive of the effectiveness of this aggregate size range to sequestered SOC in Savanna Alfisols. These results demonstrate that continuous application of soil amendments like FYM & NPK over a long term promotes soil aggregate stability and long term SOC sequestration. Hence, for sustainable production in Savanna Alfisols, there is need to design policies that will promote soil aggregate stability and long term carbon sequestration under continuous cultivation. Such policies must give attention to soil management practices that maintain higher level of SOC. Here, FYM with or without NPK was essential to increase stability of dry aggregates and SOC sequestration.

Ogunwole, J.O., D.R. Chaudhary, A. Ghosh, C.K. Daudu, J. Chikara and J.S. Patolia, 2008. Contribution of Jatropha curcas to soil quality improvement in a degraded Indian entisol. Acta Agriculturae Scandinavica Section B-Soil and Plant Science, 1-7

Soil quality improvement is critical to any rehabilitation programme in dry land degraded ecosystems. This study reports on the impact of cultivation of Jatropha curcas with or without soil amendments on the structural stability, and carbon and nitrogen content of a degraded Entisol under rehabilitation in western India. Cultivation of Jatropha curcas resulted in 11% average increase in mean weight diameter of the soil and 2% increase in soil macro-aggregate turnover. Cultivation of Jatropha curcas with nitrogen and phosphorus- or without any-amendment improved macro-aggregate stability relative to nearby native vegetation. Regression analysis showed a significant correlation between organic carbon and mean weight diameter. The cultivation of Jatropha curcas appeared to have also contributed to the quality of these soils as it maintained organic carbon and nitrogen stock and displayed a potential to increase carbon sequestration rate. Soil structure recovery under cultivation of Jatropha curcas implies a sustainable improvement in the surface integrity of these soils, which will ensure more water infiltration rather than runoff and erosion



Ph.D., Soil Science, Ahmadu Bello University, Zaria, Nigeria.Work History and Experience


M.Sc., Soil Science, Ahmadu Bello University, Zaria, Nigeria


B.Sc., Agriculture, Ahmadu Bello University, Zaria, Nigeria

Work History and Experience

since 2013

Full Professor of Soil Science, Department of Crop Production and Protection, Federal University, Dutsin-Ma

2007 - 2013

2004 - 2007

Reader [Associate Professor] of Soil Science, Department of Soil Science, Ahmadu Bello University, Zaria

1995 - 2004

Lecturer, Department of Soil Science, Ahmadu Bello University, Zaria


since 2011

Team leader, Africa Component of Australia Awards for short courses in dryland farming (AusAID, Now DFAT)



English (official)