John, N. M., Etokeren, U. E., Udo, I. I., Edem, I. D., Iren, O. B., and Asuquo, S. S. (2010). Effects of Nitrogen Enrichment on Heavy Metals Content of Cattle Dung/Poutry Manure Compost and Maize Yield. Global Journal of Agricultural Sciences, 9 (1), 51-55.
Eyong, M. O., Iren, O. B., and Akpan, J. F.(2011). A Conservation Farm Plan for Part of the Hilly Farms in Nsukka at Enugu State of Nigeria. African Journal of Agricultural Research and Development,4(3),59–64.
Imuk, E. A., Udo, S. M., and Iren, O. B. (2007). Assessment of Untreated Effluents Polluted Soil on Microbial Populations of Ekorinim, Cross River State, Niger Delta Region-Nigeria, Journal of Research in Bioscience, 3(1),67-73.
Iren, O. B., Asawalam, D. O., and Osodeke, V. E. (2011). Effects of Time and Method of Pig Manure Application on Growth Parameters and Yield of Amaranthus cruentus in a Rainforest Ultisol in Nigeria. Production Agriculture andTech nology (PAT) Journal, Nasarawa State University, Keffi, 7(1),103-116.
Iren, O. B., Asawalam, D. O., Osodeke, V. E., and John, N. M. (2011). Effects of Animal Manures and Urea Fertilizer as Nitrogen Sources for Amaranthus Growth and Yield in a Rainforest Ultisol in Nigeria. World Journal of Applied Science and Technology (WOJAST), 3(1), 73-78.
Iren, O. B. and Osodeke., V. E. (2006). Estimation of Water Requirements of Early and Late Season Pepper (Capsicum annum) in Umudike, South-Eastern Nigeria. Global Journal of Agricultural Sciences, 5(2), 95-99.
Iren, O. B., and Ibanga, I. J. (2008). The Morphological, Physical and ChemicalProperties of Soils in Selected Oil Palm Plantations in Southeastern Nigeria. Journal of Sustainable Agriculture and the Environment,10(2),160-171.
Ibanga, I. J., Umoh, N. B., and Iren, O. B. (2008). Effects of Cement Dust on Soil Chemical Properties in the Calabar Environment, Southeastern Nigeria. Communications in Soil Science and Plant Analysis, 39(3and4),551-558
Okon, P. B., Okon, A. P. Iren, O. B., and Essien, I. E. (2010). Bucket-Drip Fertigation Effects on Vegetable (Cucumber) Grown on Tropical Acid Sands. Research Journal of Soil and Water Management, Medwell Journals, 1(2), 61-67
John, N. M., Ibia T. O., Effiong G. S., Etokeren, U. E., and Iren, O. B. (2011). Response of Maize (Zea mays l.) to Different Levels of Decomposed Refuse in Uyo Municipality, Nigeria. World Journal of Applied Science and Technology (WOJAST), 3(1), 7-12.
Iren, O. B., and Amalu, U. C. (2012). Forms and Status of Potassium in some Soils Supporting Oil Palm (Elaeis guineensis, Jacq) Plantations in Cross River State, Nigeria. Communications in Soil Science and Plant Analysis, 43(14), 1949-1962.
Iren, O. B., Asawalam, D. O., Osodeke, V.E., and John, N.M. (2012). Comparative Effects of Animal Manures and Urea Fertilizer on Soil Properties in a Rainforest Ultisol. Journal of Agricultural Research and Policies, 6(2), 51–56.
Iren, O. B., John, N. M., and Imuk, E. A. (2012). Effects of Sole and Combined Applications of Organic Manures and Urea on Growth, Crude Protein and Nutrient Uptake of Fluted Pumpkin (Telfairia occidentalis, Hook f.). Journal of Agriculture, Forestry and Environment, 2(1), 78-85.
John, N. M., Uwah, D. F., Iren, O. B., and Akpan, J. F. (2013). Changes in Maize (Zea Mays L.) Performance and Nutrients Content with the Application of Poultry Manure, Municipal Solid Waste and Ash Composts. Journal of Agricultural Science, Canadian Center of Science and Education, 5(3), 270- 277.
Iren, O. B., John, N. M., and Imuk, E. A. (2013). Influence of rates of pig manure and NPK (15:15:15) fertilizer on soil chemical properties and dry matter yield of Fluted Pumpkin (Telfairia occidentalis, Hook f.). Nigerian Journal of Soil and Environmental Research, 11,55-59.
Iren, O. B., John, N. M., and Imuk, E. A. (2014).Effect of varying rates of pig manure and NPK (15:15:15) fertilizer on growth, nutrient uptake and yield of fluted pumpkin (Telfairia occidentalis Hook f.). Nigerian Journal of Soil and Environmental Research, 12, 75-81.
Iren, O. B., Uwah, I. D., and Ekpenyong, V. E. (2015). Response of fluted pumpkin (Telfairia occidentalis, hook f.) to different levels of poultry manure application in an ultisol of southeastern Nigeria. Journal of Organic Agriculture and Environment, 3,5-14.
Iren, O. B. (2015). Influence of Combined Application of Agrolyser with NPK fertilizer using Foliar and Soil Application Methods on Soil Properties and Yield of Maize (Zea mays L.). Applied Tropical Agriculture, 20(1), 67–72.
Ofem, K. I., Esu, I. E., Unuigbe, B. O., and Iren, O. B. (2015). Properties, soil forming processes and sustainable use of soils on the residual and colluvial soils in Biase LGA, Southeastern Nigeria. Nigerian Journal of Soil and Environmental Research,13,54-64.
Iren, O. B., Akpan, J. F., Ediene, V. F., and Asanga, E. E. (2015). Influence of cassava peels and poultry manure-based compost on soil properties, growth and yield of waterleaf (Talinum triangulare Jacq) in an ultisol of south-eastern Nigeria.Journalof Soil Science and Environmental Management, 6(7),187-194.
Ediene, V. F., Solomon, M. G., Iren, O. B, and Brisibe, E. A. (2015). Effects of Artemisia Annua Dried Leaves on Soil Microbial Population. International Journal for Research and Development in Technology, 3(6), 100–105.
Ufot, U. O., Iren, O. B., and Chikere Njoku, C. U. (2016). Effects of Land Use on Soil Physical and Chemical Properties in Akokwa Area of Imo State, Nigeria. International Journal of Life-Sciences Scientific Research, 2(3), 273-278.
Iren, O. B., Udoh, D. J., Ufot, U. O., and Chukwuemeka, J. N. (2016). Influence of Local Lime Materials and Organomineral Fertilizer on Fluted Pumpkin (Telfairia Occidentalis) Performance in an Ultisol of Southeastern Nigeria. International Journal of Sciences, 5(5),75-81.
Ediene, V. F., Iren, O. B., and Idiong, M. M. (2016). Effects of abattoir effluent on the physicochemical properties of surrounding soils in Calabar Metropolis. International Journal of Advanced Research, 4(8),37-41.
Iren, O. B., Udo, I. A., Asawalam, D. O., and Osodeke, V. E. (2016). Comparative effects of different nitrogen sources from organic manure and urea fertilizer on growth, crude protein and nutrient uptake of Amaranthus cruentus , European Journal of Academic Essays 3(8),296-303.
Udoh, D. J., and Iren, O. B. (2016). Evaluation of Fish Pond Effluent as an Organic Fertilizer in Comparison with Poultry and Pig Manures in the Cultivation of Pineapple (Ananas comosus). International Organization of Scientific Research - Journal of Agriculture and Veterinary Science (IOSR-JAVS), 9(9),5-10.
Udoh, D. J., Iren, O. B., and Jonathan, J. E. (2016). Comparison of Fish Pond waste Water with Manures under Garden Egg in Nigeria. Environment and Natural Resources Research, 6(3),58-64.
Iren, O. B., Uwah, I. D., and Vincent, V. M. (2017). Direct and Residual Effects of Animal Manures on Soil Properties and Yield Components of Pepper (Capsicum annum L.) in an Ultisol of Southeast Nigeria. Asian Research Journal of Agriculture, 3(3), 1-9.
Iren, O. B., Ijah, C. J., Asawalam, D. O., and Osodeke, V. E. (2016). Comparative effect of pig manure, urea fertilizer and their combinations on the performance of Amaranthus cruentus in a Rainforest Ultisol, Nigeria. Integrity Research Journal-Journal of Agricultural Science and Practice, 1, 52-57.
Iren, O. B., Udoh, D. J., Asawalam, D. O., and Osodeke, V. E. (2016). Comparative effects of different nitrogen sources and rates on soil properties and yield of Amaranthus cruentus, European Journal of Academic Essays, 3(9),304-311.
Iren, O. B., Ayito, E. O., Okon-inyang, P. O., and Ofem, K. I. (2017). Soil nutrient status and yield of waterleaf (Talinum triangulare Jacq) as influenced by rates of organomineral fertilizer in a rainforest Ultisol, Nigeria. International Journal of Applied Research, 3(5), 581-585.
Iren, O. B., and Aminu, Y. G. (2017). Soil Nutrient Dynamics and Yield of Cotton (Gossypium hirsutum L.) following an Amendment with Cattle Manure. International Journal of Plant and Soil Science, 16(2), 1-10.
Ediene, V. F., Iren, O. B., and Solomon, M. G. (2017). The Effects of Different Concentrations of Crude Aqueous Extract of Artemisia annua on Soil Microbes. Journal of Advances in Microbiology, 3(1), 1-7.
Ediene, V. F., and Iren, O. B. (2017). Impact of Abattoir Effluents on the pH, Organic Matter, Heavy Metal Levels and Microbial Composition of Surrounding Soils in Calabar Municipality. Asian Journal of Environment and Ecology, 2(3), 1-10.
Iren, O.B., and Aminu, Y.G. (2017). Nutrient Concentrations, Cotton (Gossypium Hirsutum L.) Growth and Biomass Yield as Influenced by Different Nitrogen Rates in Cattle Manure. Journal of Organic Agriculture and Environment, 5(1), 5-14
Omadewu, L. I., Iren, O. B., and Eneji, A. E. (2017). Optimizing Nitrogen Rates and Plant Density for Cotton Cultivars (Gossypium. SPP.) in the Nigerian Savanna. Asian Journal of Soil Science and Plant Nutrition, 1(4), 1-15