Dr. Mabel Ifeoma Onwuka

Associate Professor of Soil Chemistry                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    Room 22 CCSS Building

Department of Soil Science and Meteorology

College of Crop and Soil Sciences


Educational record

Doctorate (Soil Chemistry), Michael Okpara University of Agriculture Umudike, 2008

Master of Science (Soil Physics), Michael Okpara University of Agriculture Umudike, 2003

Bachelor of Science (Soil Science), Enugu State University of Science and Technology, 1997

Area of Expertise

·         Soil Acidity

·         Soil Biochemistry

·         Soil Health Restoration

·         Organic wastes re-cycling

·         Soil Conservation

·         Sustainable tropical soil management and Gender -Mainstreaming

·         Soil Organic Matter

·         Soil Fertility and Productivity

·         Carbon sequestration

·         Rural and Urban organic vegetable production

Research Focus

My research seeks to have a better understanding of the core principles of soil reaction and its role in soil chemical properties especially in the Tropics. I am particularly concern with the agricultural practices that diminish soil acidity’s effect on soil nutrients availability especially nitrogen and phosphorus, soil organisms’ activities and organic matter build-up. This research area is significant, relevant and also a panacea in combating the chemical, biological and physical soil degradation in order to restore soil health, improve soil fertility and productivity to ensure food security at local, regional and global level.

The conversion of safe, decomposable agricultural and municipal wastes as a method of re-cycling has been the main thrust of my research. Through this process rich and nutritive compost, ash, biochar that increase soil nutrients, sequestrate carbon to reduce climate change and stabilize soil particles, have been developed.

Most recently, my interest and efforts have been on nanotechnology of organic soil inputs for soil productivity improvement; mainstreaming gender in sustainable soil conservation, waste conversion and rural/ urban organic vegetables production to achieve healthy nutrition, ensure food security as well as healthy environment.

Courses taught at Undergraduate level

SSA 422 Soil fertility and Water Management (2 units)

SSA 511 Soil and Plant Analyses (2 units)

SSA 515  Soil-Plant-Water Relations (2 units)

SSA 523  Soil Chemistry and Microbiology (2 units)

SSA 517  Soil Biology and Biochemistry   (2 units)

Courses taught at Postgraduate level

SSA 714          Soil Chemistry and Microbiology 2 units (PGD)

SSA 725          Soil-Water-Plant Relations     2 units (PGD)

SSA 812          Advanced Soil Chemistry       3 units (M.Sc)

SSA 815          Soil Microbiology                  3 units (M.Sc.)

SSA 822          Soil and Plant Analysis           3 units (M.Sc.)

SSA 922          Soil Mineralogy                      3 units (PhD)

Teaching Focus

I aim at producing students who will have great passion for science, especially soil science and as well as become reputable leaders, in their chosen careers.  I adopt the approach of creating enabling classroom, laboratory and field environments that motivate, encourage and provide opportunities for the students to become result oriented, team players, critical thinkers and problem solvers of soil and environment related issues. My teaching involves using stimulating theories and practical sessions to explain factors affecting soil reactions and its amelioration, nutrient cycling, nutrient leaching, organic matter dynamics, soil microbes activities, soil water movement and uptake by plants, processes that escalate soil degradation and remedies, heavy metals contamination and remediation, processes of compost, biochar and ash production. My focus is also on carbon sequestration through biochar, land use changes and effect on soil productivity and food security, soil and water conservation techniques in improving soil fertility and productivity, laboratory and field analyses of soil nutrients to detect any change in the nutrient status of the soil.

Students supervised (2006-date)

·         B.Sc. ( completed 29; current 3 )

·         M.Sc. ( completed 3; current 3)

·         PhD ( Completed 1(Minor Supervisor); Current 1(Minor Supervisor)

Leadership and Administrative skills

2019 – Date    College of Crop and Soil Sciences representative to MOUAU Senate

2016 – Date    Vice President (South East) Biochar Initiatives of Nigeria

2014 – Date    Staff overseeing the activities of the Soil Science and Meteorology Departmental Laboratory

2014 – 2017    Desk Officer for Women in Agriculture at Michael Okpara University of Agriculture Umudike

2013 – 2015    Soil Science and Meteorology Departmental Examination Officer

2011-2014      College Representative to College of Agricultural Economics and Rural Sociology Board

2011 – Date     Matron to the Students Union of the Department of Soil Science and Meteorology, MOUAU

2003 – 2011    Coordinator for 100 levels Farm practice (A University wide course for all 100 level students)

2003 – Date    Students’ Academic Adviser and Mentor

Awards, Honors and Grants

2017  Rothamsted International Fellowship Award, United Kingdom funded by Lawes Trust.

2014  Selected participant:   Australia Awards –Fellowship sponsored by Australia  Government.

2014  Tetfund sponsored research grant (Ameliorating effects  of biochar on soil properties, yield and crude protein content of Soybean (Glycine Max (LMerr) in an acidic Ultisols of Southeast Nigeria.

2011   Selected participant:  International Post- Graduate  in Crop production under Saline Stress; held at the Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Israel sponsored by Israel Government (MASHAV)

2007    ETF capacity building Grant for academic staff of Michael Okpara University of Agriculture Umudike


Ifebude, E.C. and Onwuka, M.I (2020). Biochar amendments and their residual effect on soil chemical properties and growth components of Greenleaf (Amaranthus caudatus) in nutrients depleted Nigeria Journal of Sustainable Agriculture and the Environment Volume 18 Number 1: 43-58.


  Onwuka, M. I. , Okonta, U. and Asobia, P. C. (2020). The impact of land use types and acidity indices on soil humic fractions quantities at Umudike, Tropical Rainforest, Nigeria. Nigeria Journal of Soil Science 30(3) 2020 42-52


Onwuka, M.I., Ejikeme, A. L., Uzoma, O. and Oguike, P. C. (2020). Land –use change effects on Soil quality at Umudike Area, Abia State, South-East Nigeria. Nigeria Agricultural Journal ISSN: 0300-368XVolume 51 Number 1, April 2020 Pg. 109-118


  • Onwuka, M. I., Okereke, J. C., and Fashola, M. S. (2019). Cow Dung Forms and their Effect on Microbial Community of Degraded Ultisols of some Smallholder Women Farmers’ Fields in the Rainforest Zone of Nigeria. Direct research journal of agriculture and food science, Vol. 7(6), 110–116.
  • Onwuka, M. I., Effedua,  B. A. and  Alfred, L. C. (2019). Transformed Cattle dung: Its effect on Forms of Potassium, Soil Acidity indices and C4 Crop assessed from Smallholder Women’s Farms.  Nigerian Journal of Agriculture, Food and Environment. 15(1): 111-121.


Selected Publications

Huang, Y., Wang, C., Lin, C., Zhang, Y., Chen, X., Tang, L., Liu, C., Chen, Q., Onwuka, M.I., & Song T. (2019). Methane and Nitrous Oxide Flux after Biochar Application in Subtropical Acidic Paddy Soils under Tobacco-Rice Rotation Sci Rep 9, 17277

Onwuka, M. I., Okereke, J. C., and  Fashola, M. S. (2019). Cow Dung Forms and their Effect on Microbial Community of Degraded Ultisols of some Smallholder Women Farmers’ Fields in the Rainforest Zone of Nigeria. Direct research journal of agriculture and food science, Vol. 7(6), 110–116.

Onwuka, M. I., Effedua,  B. A. and  Alfred, L. C. (2019). Transformed Cattle dung: Its effect on Forms of Potassium, Soil Acidity indices and C4 Crop assessed from Smallholder Women’s Farms.  Nigerian Journal of Agriculture, Food and Environment. 15(1): 111-121.

Onwuka, M.I.  and Nwangwu B.C. (2016) Characterization of biochar produced from diverse feedstocks used as amendment on acidic Ultisols at Umudike, Abia State. Nigeria Journal of Soil Science ISSN 2201-4357 Volume 9, Number 2, 158-174.

Onwuka, M.I.  and  Nwangwu B.C. (2016). Roles of biochar produced from animal and plant wastes on okra (Abelmoschus esculenta) growth in Umudike area of Abia State, Nigeria.  Journal of Agriculture and Sustainability ISSN 2201-4357 Volume 9, Number 2, 158-174

Onwuka, M.I. (2016). Mitigation of Chemically Degraded Soil of Coastal Plain Sand with Biochar and Other Soil Amendments. International Journal of Research Studies in Agricultural Sciences (IJRSAS) Volume 2, Issue 5, pp 27-34

Nwachukwu, O. I. Onwuka, M. I. and Osodeke, V. E. (2016) Effect of industrial wastes on soil chemical properties and heavy metal levels in the vicinity of two factories in Abia State, Nigeria. Nigeria Journal of Soil and Environmental Research, 14: 193-197

Onwuka, M.I., Adiele, P.O. and Ogbonna, K.E. (2015) Improving the soil available phosphorus and exchangeable calcium of three parent materials of the smallholder farmers uses amendments in Abia State, Southeastern Nigeria. International Journal of Advanced Research (2015), Volume 3, Issue 8, 172-183.

Onwuka, M.I., Ozurumba, U.V and Nkwocha, O.S. (2016). Changes in soil pH and Exchangeable acidity of selected parent materials as influenced by amendments in South East of Nigeria. Journal of Geoscience and Environment Protection. Vol 4:  80-88

Onwuka, M.I. and Umeh, C.M. (2015) Synergistic effects of biochar with other amendments on organic carbon of three parent materials of smallholder women farmers in Abia State, Nigeria. Proceedings of 2nd International Conference and Exhibition (OWSD-FUTA).  523-528

Onwuka, M. I. and Osodeke, V.E (2015). Effects of agricultural waste ash on nutrients concentration and yield of maize (zea mays l) in a Haplic Acrisol of Southeastern Nigeria Journal of Sustainable Agriculture and the Environment ISSA 119-8152, Vol 16 No 1: 139-157

Onwuka, M.I., Chude, V.O and Ogwuegbu, G.C (2012) Remediation of spent engine oil polluted soil using types of organic manure and their effects on maize growth. Nigeria Journal of Soil Science Vol 22(2) 248-253

Onwuka, M.I. and Ihejiakor, C.N. (2013). Residual Effect of Integrated Nutrient Management Approach on the growth and yield of Amaranthus (Amaranthus cruentus L) on acidic soils of Southeastern Nigeria. Greener Journal of Agricultural Science Vol 3(1) pp 778-786

Onwuka, M.I. and Idiong, N. (2012) Measurement of the amount of selected Greenhouse gas (carbon dioxide) emitted during a short term decomposition of applied animal manure on an acidic Typic Kandiudult. Production Agriculture and Technology 8 (2): 37-50

Onwuka, M.I. and Kanu, E.C. (2012) Residual effect of integrated soil fertility management approach on soil acidity indices and selected chemical properties of a degraded Haplic Acrisol of Southeastern Nigeria. Nigeria Journal of Soil and Environmental Research. Vol. 11: 60 – 68 

Onwuka, M. I., Osodeke, V.E. and Ano, A.O. (2011). Influence of some non-conventional liming materials on some soil acidity indices in an Ultisols of Southeastern Nigeria. The Nigerian Journal of Agriculture Vol 42 pp 301-310

Onwuka, M.I. (2011). The chemical composition of different sources of liming   Materials and their effect on soil chemical properties. Journal of Environmental Sciences and Resource Management Volume (3) 57-67

Onwuka, M. I. and Nsofor, H.O (2011). The effect of kitchen residue ash, poultry manure and goat dung on soil properties and yield of cowpea (Vigna unguiculata) in a Typic Kandiudult of Southeast Nigeria. Journal of Agriculture and food Science. Vol 9 (1) 12-21.

Onwuka, M. I., Osodeke, V.E. and Ano, A.O. (2010). Evaluation of some locally sourced liming materials on soil acidity of Southeastern Nigeria. An incubation study. International Journal of Agriculture, Vol 1, No 2 pp 104- 110

Onwuka, M. I., Osodeke, V.E. and Ano, A.O. (2010). Assessment of the effect of some liming materials on some soil chemical properties in a degraded Ultisol of Southeastern Nigeria. Nigerian Journal of Soil Science Vol 20 (2) :54-62

Onwuka, M. I. and Igwe, A. C. (2010). Effect of types of organic waste on soil contaminated with spent engine oil in Umuahia Metropolis, Abia State. Journal of Environmental Sciences and Resource Management (2) 71-80.

Onwuka, M. I., Osodeke, V.E. and Ano, A.O. (2009). Use of liming materials to reduce soil acidity and affect maize (Zea mays L) growth parameters in Umudike, Southeast Nigeria. Production Agriculture and Technology 5 (2):386-396.

Onwuka, M .I. and Ogbonna, E .A.G (2009). Effect of different kitchen residue  ash sizes on soil acidity amelioration in an Ultisol. Proceedings of the 33rd    Annual Conference of the Soil Science Society of Nigeria, held at Ekiti State. Pp 184-189

Onwuka, M.I. (2009). Effect of different levels of Cocoa pod husk ash on the growth of mungbean (Vigna radiate. L.WILCZEK) and soil properties at Umudike area of Abia State. Proceedings of the 43rd Annual Conference of the Agricultural Society of Nigeria held at Abuja. Edited by Olojede, A.O., Okoye, B.C., Ekwe, K. C and Chukwu, G.O. Pp 876-878

Onwuka, M.I, Osodeke V.E and N.A. Okolo (2007) Amelioration of soil acidity using cocoa husk ash for maize production in Umudike area of South East Nigeria. Tropical and Subtropical Agroecosystem. 7: 41-45.

Onwuka, M.I and Asawalam D.O. (2006). Comparative effect of the animal manures on some physical properties of an Ultisol in Southeast of Nigeria. Journal of the Science of Agriculture, Food Technology and the Environment 6: 53-59.

Osodeke, V.E, Onwuka, M.I and Ugwu, N.B. (2006). The effects of Agrolyser on    the performance of Okra (Abelmoschus esculentus L. Moench) and Physico-chemical properties of an Ultisol in Southeastern Nigeria. Journal of Applied Chemistry and Agriculture Research 99: 122-127.

Onwuka, M.I. and Asawalam, D.O. (2006). Influence of the animal manure amendments on soil aggregate stability and organic matter content of an Ultisol at Umudike, Abia State. Proceeding of the 40th annual conference of the Agricultural Society of Nigeria, held at Abia State. Pp 431-434.

Invited papers

2019    An overview on farmers’ capacity building training and the importance of adapting to new policies and best practices in farming. An invited paper presented at capacity building training of farmer’s on decision-making implication towards new policy and best practices in Enugu State. Organized by Directorate of Technical Cooperation in Africa (DTCA), Ministry of Foreign Affairs Nigeria from 16th to 16th August , 2019 at Enugu State, Nigeria

2016    Biochar: the hidden wealth in waste. A key note speech presented at the  2nd Annual Conference of Biochar Initiative of Nigeria (BIN) held from September 6th-9th 2016 at Bowen University Iwo, Osun State

Selected conferences, symposium, workshops and trainings attended

2002    Agriculture Society of Nigeria Annual Conf. held at Federal University of  Technology Owerri  (FUTO), Imo State, Nigeria

2003    27th Soil Science Society of Nigeria Annual Conference held at NRCRI,   Umudike, Abia State, Nigeria

2006    Agriculture Society of Nigeria Annual Conf. held at National Root Crops Research Institute Umudike, Abia State, Nigeria

2009    33rd Soil Science Society of Nigeria Annual Conference held at Federal University Ado Ekiti, Ekiti State, Nigeria

2010    34th Soil Science Society of Nigeria Annual Conference held at Institute of  Agricultural Research and Training Ibadan, Oyo State, Nigeria

2011    6th International Exhibition and the 3rd International Conference on Water  Technologies, Renewable Energy and Environmental Technology, Israel

2012    36th Soil Science Society of Nigeria Annual Conference held at University of Nigeria Nsukka, Enugu State, Nigeria

2012    1st International Training Course on Biochar Production, Testing and Application at Nanjing, China

2014    38th Soil Science Society of Nigeria Annual Conference held at University of  Uyo, Akwa Ibom State, Nigeria

2014    Australia Awards -African Fellowship in Soil and Water Conservation Agriculture at Australia and Ethiopia

2015   Training of Trainers of Capacity Building in Agricultural Education in Nigeria (CBAEN) Organized by The School of Agricultural Forest and   Food Science (HAFL) of Bern University of Applied Sciences in   Zollikofen, Switzerland held at ARMTI Ilorin and Federal College of Agriculture, Akure Nigeria.

2015   Regional workshop on the use of Gender and Transformative Leadership curriculum for Higher Institutions Lecturers in Nigeria

2016   2nd Biochar Initiative of Nigeria Conference held at Bowen University, Osun State, Nigeria

2017     6th International Symposium on Soil Organic Matter, held at Rothamsted Research, Harpenden, United Kingdom

2018     Equality and Diversity course and unconscious  bias at RRes, North Wyke

2018     Intermediate Excel training at RRes North Wyke, UK

2018     Introduction to Statistics and Data Analysis at  RRes North Wyke, UK

2018     Scientific technical writing course at RRes North Wyke, UK

2018      4th Biochar Initiative of Nigeria Conference held at Federal University of  Agriculture, Abeokuta, Ogun State, Nigeria

2019      Symposium: Irrigation and Water Resources Management for Agriculture:  Achieving Impact for Africa, held at IITA Ibadan, Oyo State, Nigeria on 28th March, 2019

2019      Statistical Computing for Agricultural Research held at Michael Okpara University of Agriculture Umudike by IITA Ibadan, Nigeria


Conference Proceeding

Onwuka, M.I and Chilaka, C.O (2021). Evaluation of organic matter and aggregate stability status of amended slash-and-burn soil in Rainforest, Abia State Nigeria. Proceedings of the 5th Biennial Conference of the Organization for Women held in Michael Okpara University of Agriculture Umudike from 14th to 17th June 2021

Newspaper articles

Onwuka, M.I. (2021). Food Security: Don advocates home gardening to avert food security. National Ambassador, (May 23, 2021), Vol. 22 (064) pp 17.  













6th General Assembly and International Conference of The Organization for Women in Science for the Developing World (OWSD). November 8-19, 2021. Online Event


5th Biennial International Conference of Organization for Women in Science for the Developing World (OWSD), held at Michael Okpara University of Agriculture Umudike from 14th -17th June 2021.


45th Soil Science Society of Nigeria Annual Conference held at Bowen University Owo, Osun State Nigeria.


4th Biochar Initiative of Nigeria Conference held at Federal University of Agriculture, Abeokuta, Ogun State, Nigeria.

Membership to Professional Bodies

·         2003      Soil Science Society of Nigeria

·         2003      Agricultural Society of Nigeria

·         2010      Organization for Women in Science for the Developing World

·         2012      International Union of Soil Sciences

·         2013      International Biochar Initiative

·         2015      Biochar Initiative of Nigeria

·         2017      British Society of Soil Science

Professional Networking/ Impact Tracking/Online Data Sharing Platforms



Google Scholar: mabel ifeoma=Pxhv0sYAAAAJ&hl=en



Voluntary and Community Services

2019    Chairperson Hope for farmers, women and girls initiatives ( NGO involved in building farmers’ capacities, empower women through training, mentor female students in higher institutions and  motivate girls in primary and post- primary schools to develop passion for Science Technology Engineering and Mathematics (STEM) in Nigeria)

2019    Special Marshal Sector 093 unit 8 ( Volunteer arm of the Federal Road Safety Corps that help control traffic; involve in road safety campaigns in schools, organizations, motor parks among others)

2008 – date  Member Christian Support Initiative (NGO, involved in free  medical care and community development in Nigeria)

1999 – date  Women Coordinator at The Redeemed Christian Church of God, Abia Province 3 (His Glory Parish, Unity Parish, City of  Praise Parish and Glory Palace An arm of The Redeemed Christian Church of God, (a Christian mission) that caters for the spiritual, mental and physical needs of women and their families.

Profile Summary

Dr. Mabel Ifeoma Onwuka is actively involved in teaching, research and community development. Her teaching styles, leadership skills and lively classes make her students develop interest in topics in soil chemistry, biochemistry, microbiology and environmental chemistry that she teaches. Through her research that spans from soil acidity amelioration, soil health restoration, organic waste re-cycling, soil fertility and productivity improvement among others, she has been able to proffer solutions to some of the soil related issues in her region. Her active involvement in community development through her voluntary work has given her opportunities to enhance the lives of some poor- resource farmers in some communities. Her achievements and contributions to the society have been featured in the following:

The Northern Daily Leader, Australia @

British Society of Soil Science, Auger Magazine, December 2017, page 10 @

Rothamsted Research Center International Women’s Day 2018 @ 

Australia- Awards Fellowship -Alumni reflection World Food Day 2019 @ 

Dr. Onwuka is happily married to Professor Greg Onwuka and their union is blessed with children.

Department Contact Info

Bachelor Of Science in Business Administration

1810 Campus Way NE
Bothell, WA 98011-8246


Mon – Fri 9:00A.M. – 5:00P.M.

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