Official Website Professor Dr. Osumanu Haruna Ahmed | UNIVERSITI PUTRA MALAYSIA BINTULU SARAWAK CAMPUS
» Official Website Professor Dr. Osumanu Haruna Ahmed

Official Website Professor Dr. Osumanu Haruna Ahmed

  

Ahmed Osumanu Haruna (Prof. Dr.)

PROFESSOR/DIRECTOR, INSTITUTE OF ECOSYSTEM SCIENCE BORNEO
Agricultural Science (Univ. of Ghana), M.Sc. (UPM), Ph.D. (UPM)
Field of Expertise : Soil Fertility and Management
Tel. : +6086-855406
Email: osumanu@upm.edu.my
ORCID: http://orcid.org/0000-0002-3240-8081
Google Scholar: Ahmed Osumanu Haruna
ResearchGate: https://www.researchgate.net/profile/Osumanu-Ahmed


Current Research Interest

  1. Ammonia Volatilization Control
  2. Humic Substances Studies
  3. Nutrient Cycling and Budget
  4. Soil Processes and Plant Nutrition
  5. Fertilizer Technology
  6. Wastes Management
  7. Soil Carbon Sequestration


Selected Publications

Books

Ahmed Osumanu Haruna, Alicia Vanessa Jefary, Wendy Luta, and Liza Lim Nuriati (2018). Cultivating tropical peat soil and greenhouse gases transportation. Universiti Putra Malaysia: Serdang, Malaysia. (In press).

Ahmed Osumanu Haruna and Amelia Tang (2018). Biofertilizer potentials of cellulotic, nitrogen-fixing, and phosphate-solubilizing bacteria. Universiti Putra Malaysia: Serdang, Malaysia. (In press).

Ahmed Osumanu Haruna and Huck-Ywih Ch’ng. (2017). Statistical Analysis System (SAS) for Agricultural Research. Universiti Putra Malaysia: Serdang, Malaysia. Pp 175.

Ahmed Osumanu Haruna, Nor Aainaa Hasbulla, and Nik Muhamad Ab Majid. 2017. Zeolites to unlock phosphorus fixation in agriculture. Universiti Putra Malaysia: Serdang, Malaysia. Pp 188.

Ahmed Osumanu Haruna and Maru Ali. 2017. Using biochar and urea to improve rice production on tropical acid soils. Universiti Putra Malaysia: Serdang, Malaysia. Pp 109.

Ahmed Osumanu Haruna, Latifah Omar, and Nik Muhamad Ab Majid. 2017. Enhancing nitrogen availability using compost and clinoptilolite zeolite. Universiti Putra Malaysia: Serdang, Malaysia. Pp 261.

Ahmed Osumanu Haruna, Palanivell Perumal, and Nik Muhamad Ab Majid. 2017. Improving rice yield through the use of organic amendments. Universiti Putra Malaysia: Serdang, Malaysia. Pp 280.

Ahmed Osumanu Haruna, Huck-Ywih Ch’ng, and Nik Muhamad Ab Majid. 2015. Improving phosphorus availability for plant uptake in tropical acid soils using organic amendments derived from agro-industrial wastes. Universiti Putra Malaysia Press: Serdang, Malaysia. Pp 310.

Ahmed Osumanu Haruna and Liza Nuriati Lim Choo. 2015. Greenhouse gas emission and carbon leaching in pineapple cultivation on tropical peat soils. Universiti Putra Malaysia Press: Serdang, Malaysia. Pp 157.

Ahmed Osumanu Haruna 
and Nik Muhamad Ab Majid. 2014. Zeolite and Plants Nutrient Use. Universiti Putra Malaysia Press: Serdang, Malaysia.  Pp 123.

Ahmed Osumanu Haruna
and Nik Muhamad Ab Majid. (2014). Humic substances and urea use in agriculture. Universiti Putra Malaysia Press: Serdang, Malaysia. Pp 169. 

Ahmed Osumanu Haruna,
 Ahmad Husni Mohd. Hanif, Mohd Hanafi Musa and Anuar Ab. Rahim. 2013. Sustainable Production of Pineapples on Tropical Peat Soils. Universiti Putra Malaysia Press: Serdang, Malaysia. Pp 144.

Ahmed Osumanu Haruna,
 Huck-Ywih Ch’ng, and Nik Muhamad Ab Majid. 2012. Rehabilitation of Degraded Tropical Forests and Soil Carbon Storage. Universiti Putra Malaysia Press: Serdang, Malaysia. Pp 162.

Ahmed Osumanu Haruna,
 Latifah Bte Omar, Auldrey Chaddy Petrus and Nik Muhamad Ab Majid. 2012. Sustainable production of sago grown on tropical peat. Universiti Putra Malaysia Press: Serdang, Malaysia. Pp 185.

Ahmed Osumanu Haruna,
 Anuar Abd Rahim and Ahmad Husni Mohd Hanif. 2006. Some essentials of good scientific research. Universiti Putra Malaysia Press: Serdang, Malaysia. Pp 76.


Chapter in Book

Osumanu Haruna Ahmed, Alicia Vanessa Jeffary, Mohamadu Boyie Jalloh and Hamdan Jol. (2015). Amending tropical peat soil with clinoptilolite zeolite to reduce leaching of nitrate and ammonium ions. In: Advances in Tropical Soil Science vol. 3. Universiti Putra Malaysia Press: Serdang. Pp.142-171.

Osumanu Haruna Ahmed, Nur Asyira Binti Azrumi, Mohamadu Boyie Jalloh and Hamdan Jol. (2015). Using clinotilolite zeolite for enhancing potassium retention in tropical peat soil. In: Advances in Tropical Soil Science vol. 3. Universiti Putra Malaysia Press: Serdang. Pp.112-127.

Osumanu Haruna Ahmed, Sa’idah Mardhiah bt Mohd Izra’ai, Mohamadu Boyie Jalloh and Nik Muhamad Ab Majid. (2014). Improving phosphorus availability in acidic mineral soils. In: Natural Resources and Biodiversity. Universiti Putra Malaysia Press: Serdang. Pp.7-25.

Hamdan Jol, Osumanu Haruna Ahmed and Isharudin Mat Isa. 2013. Mineralogy and potassium supply of some weathered tropical soils developed from different parent materials. In: Advances in Tropical Soil Science vol. 2. Universiti Putra Malaysia Press: Serdang. Pp.1-17.

Huck-Ywih Ch’ng, Osumanu Haruna Ahmed, and Nik Muhamad Ab Majid. 2013. Assessment of Soil Fertility in a Tropical Rehabilitated Forest.  In: Advances in Tropical Soil Science vol. 2. Universiti Putra Malaysia Press: Serdang. Pp.18-38.

Omar Latifah, Osumanu Haruna Ahmed and Nik Muhamad Abdul Majid. 2012. Effect of Mixing Urea with Sago (Metroxylon sagu), Waste Water and Peat Soil Water on Minimizing Ammonia Volatilization and Improvement of Nutrient Use Efficiency of Maize (Zea mays L.).  In: Advances in Tropical Soil Science vol. 2. Universiti Putra Malaysia Press: Serdang. Pp.83-97.

Osumanu Haruna Ahmed, Anuar Abdul Rahim, Aminuddin Hussin, Ahmad Husni Mohd Hanif, Siva K. Balasundram and Mohamed Hanafi b. Musa. 2011. Towards sustainable cultivation of pineapples on tropical peat soils. In: Advances in Tropical Soil Science vol. 1. Universiti Putra Malaysia Press: Serdang. Pp.269-287.

Ahmad Husni Mohd Hanif, Alagie Bah, Firdaus Suleiman and Osumanu Haruna Ahmed. 2011. Nutrient dynamics of a pineapple plantation on tropical peat. In: Advances in Tropical Soil Science vol. 1. Universiti Putra Malaysia Press: Serdang. Pp.258-268.

Shaharudin Saamin and Osumanu Haruna Ahmed. 2007. Bibliography on research and development of Sago, peatland, associated soils and crops. Univision Press Sdn. Bhd. Pp.269-285.

Anuar Abd. Rahim, Goh, K. J., Ahmed, O. H., Gan, H. H. and Balasundram, S. K. 2005. Experimental designs, analyses and interpretations in research and development trials. In Proceedings of MOSTA best practices workshops: agronomy and crop management, Malaysia, March to August 2004.  Soon, C. P. and Pau, T. Y. (Eds.). Malaysian Oil Scientists' and Technologists' Association. Pp. 87-132

Module (Chapter)

Nik Muhamad Ab Majid and Osumanu Haruna Ahmed. (2015). High impact research. In AKEPT Malaysia, Higher Education Leadership Academy, Module on Innovation. Ed. Mohd Jailani, M.N. AKEPT Malaysia, Higher Education Leadership Academy, Ministry of Education Malaysia. Pp. 5-44. (In press).

Journals

Ahmed, O.H and Leng, Y. 2018. A brief review on climate change in tropical peat land. Geoscience Frontiers. (In Press).

Kevin, S., Ahmed, O.H., Khew, C.Y. and Zehnder, J.A.M. 2018. Introducing natural farming in black paper (Piper nigrum L.) cultivation. International Journal of Agronomy. (In Press).

Asap, A., Haruna, A., Majid, N., Ali, M., 2018. Amending triple superphosphate with chicken litter biochar improves phosphorus availability. Eurasian Journal of Soil Science, 7(2): (In press).

Palanivell, Perumal, Osumanu Haruna Ahmed, and Nik Muhamad Ab Majid. "Minimizing Ammonia Volatilization from Urea in Waterlogged Condition Using Chicken Litter Biochar." Communications in Soil Science and Plant Analysis 48.17 (2017): 2083-2092.

Latifah, Omar, Osumanu Haruna Ahmed, and Nik Muhamad Abdul Majid. "Enhancing nitrogen availability from urea using clinoptilolite zeolite." Geoderma 306 (2017): 152-159.

Latifah, Omar, Osumanu Haruna Ahmed, and Nik Muhamad Abdul Majid. "Soil pH Buffering Capacity and Nitrogen Availability Following Compost Application in a Tropical Acid Soil." Compost Science & Utilization (2017): 1-15.

Latifah, Omar, Osumanu Haruna Ahmed, and Nik Muhammad Abdul Majid. "Enhancing Nutrients Use Efficiency And Grain Yield of Zea Mays L. Cultivated on a Tropical Acid Soil Using Paddy Husk Compost and Clinoptilolite Zeolite." Bulgarian Journal of Agricultural Science 23.3 (2017): 418-428.

Mohd Rashid Mohd Rakib, Choon‐Fah Joseph Bong, Ahmad Khairulmazmi, Abu Seman Idris, Mohamadu Boyie Jalloh, Osumanu Haruna Ahmed. 2017. Association of Copper and Zinc Levels in Oil Palm (Elaeis guineensis) to the Spatial Distribution of Ganoderma Species in the Plantations on Peat. Journal of Phytopathology, 165(4): 276-282.

Omar Latifah, Osumanu Haruna Ahmed, Nik Muhamad Abdul Majid. 2017. Short Term Enhancement of Nutrients Availability in Zea mays L. Cultivation on an Acid Soil Using Compost and Clinoptilolite Zeolite. Compost Science & Utilization, 25(1): 22-35.

Heng, Roland Kueh Jui, Nik Muhamad Abd Majid, Seca Gandaseca, Osumanu Haruna Ahmed, Sylvester Jemat, Melvin Ku Kin Kin, and Jimmy Teo Chee Kiong. "Akademia Baru." Journal of Advanced Research Design 36, no. 1 (2017): 25-33.

Huck Ywih Ch'ng, Osumanu Haruna Ahmed, Nik Muhamad Ab Majid, Mohamadu Boyie Jalloh. 2017. Reducing Soil Phosphorus Fixation to Improve Yield of Maize on a Tropical Acid Soil Using Compost and Biochar Derived from Agro-Industrial Wastes. Compost Science & Utilization, 25(2):82-94.

Luta, O. H. Ahmed, R. K. J. Heng, L. K. N. Choo. 2017. Water table fluctuation and carbon dioxide emission from a tropical peat soil cultivated with pineapples (Ananas comosus L. Merr). International Journal of Biosciences, 10(1):172-17.

Liza Nuriati Lim Kim Choo and Osumanu H. Ahmed. 2017. Methane emission from pineapple cultivation on a tropical peatland at Saratok, Malaysia. Sustainable Agriculture Research6(3), 64.

Omar Latifah, Osumanu Haruna Ahmed, Nik Muhamad Abdul Majid. 2017. Enhancing nutrients use efficiency and grain yield ofZea mays L. cultivated on a tropical acid soil using paddy husk compost and clinoptilolite zeolite. Bulgarian Journal of Agricultural Science, 23(3), 418-428.

Liza Nuriati Lim Kim Choo and Osumanu H. Ahmed. 2017. Nitrous oxide emission of a tropical peat soil grown with pineapple at Saratok, Malaysia. International Journal of Soil Science, 6(3), 75.

Huck Ywih Ch'ng, Osumanu Haruna Ahmed, Nik Muhamad Ab Majid. 2016. Improving Phosphorus Availability, Nutrient Uptake and Dry Matter Production of Zea Mays L. on a Tropical Acid Soil Using Poultry Manure Biochar and Pineapple Leaves Compost. Experimental Agriculture, 52(3): 447-465.

Ahmed Osumanu Haruna, Palanivell Perumal, and Nik Muhamad Ab Majid. 2016. Minimizing ammonia volatilization from urea, improving lowland rice (cv. MR219) seed germination, plant growth variables, nutrient uptake, and nutrient recovery using clinoptilolite zeolite. Archives of Agronomy and Soil Science, 62(5):708-724.

Roland Jui Heng Kueh, Nik Muhamad Majid, Osumanu Haruna Ahmed, Seca Gandaseca. 2016. Assessment of Carbon Stock in Chronosequence Rehabilitated Tropical Forest Stands in Malaysia. Journal of Forest and Environmental Science, 32(3):302-310.

Roland Kueh Jui Heng, Nik Muhamad Ab Majid, Seca Gandaseca, Osumanu Haruna Ahmed, Silvester Jemat, Melvin Ku Kin Kin. 2016. Assessment of Floristic Composition in a Rehabilitated Forest, Sarawak, Malaysia. Borneo Journal of Resource Science and Technology, 2(2):60-66.

Latifah Omar, Ahmed Osumanu Haruna, Nik Muhammad Majid. 2016. Effect of Organic Amendment Derived from Co-Composting of Chicken Slurry and Rice Straw on Reducing Nitrogen Loss from Urea. Communications in Soil Science and Plant Analysis, 47(5): 639-656.

Ywih Ch'ng Huck, Haruna Ahmed Osumanu, Muhamad Nik. 2016. Minimizing phosphorus sorption and leaching in a tropical acid soil using Egypt rock phosphate with organic amendments. Philippine Agricultural Scientist, 99(2): 176-185.

Hoque M.M., Abu Hena M. K., Ahmed O.H., Idris M.H., Hoque A.T.M. Rafiqul, and Billah M. M. (2015). Can mangroves help combat sea level rise through sediment accretion and accumulation? Malaysian Journal of Science, 34 (1): 23-30.

Maru, A., Ahmed, O.H. and Walter, C.P. (2015). Co-application of chicken litter biochar and urea only to improve nutrients and yield of Oryza sativa L. cultivation on tropical acid soil. The Scientific World Journal: TSW Soil Science, 2015:1-12.

Palanivell, P., Ahmed, O.H. Susilawati, Nik Muhammad Ab. Majid and M.B. Jalloh. (2015). Minimizing Ammonia Volatilization from Urea, Improving Lowland Rice (cv. MR219) Seed Germination, Plant Growth Variables, Nutrients Uptake, and Nutrients Recovery Using Clinoptilolite Zeolite. Archives of Agronomy and Soil Science, 2015:1-17.

Yusof, M.R., Ahmed, O.H. and Zakry, F. A. (2015). Effects of biochar and chicken litter ash on selected soil chemical properties and nutrients uptake by Oryza sativa L. var MR 219. International Journal of Biosciences, 6(3):360-369.

Latifah, O., Ahmed, O.H. and Nik Muhamad, A.M. (2015). Compost maturity and nitrogen availability by co-composting of paddy husk and chicken manure. Waste Management Research, 33 (4):1-10.

Hoque MM, Abu Hena MK, Hanafi I, Ahmed OH, Saifullah ASM, Billah MM. (2015). Status of Some Fishery Resources in a Tropical Mangrove Estuary, Sarawak, Malaysia. Marine Biology Research, 2015:1-12.

Hoque MM, Abu Hena MK, Ahmed OH, Hanafi I, Hoque ATMR, Billah MM. (2015). Litterfall Production in a Tropical Mangrove Mangrove of Sarawak, Malaysia. Zoology and Ecology, 2015:1-9.

Hun, KS, Balasundram, Anuar, AR, Ahmed O.H. and Aminudin. H. (2015). Response of Irrigated Direct-Seeded Rice Yields to Different Nitrogen Rates Precipitation Patterns. International Journal of Tropical Agriculture, 2015:565-570.

Chandra IA, Seca G, Noraini R, Ahmad MMP, Ahmed OH, Hazandy AH, and Nik Muhamad A M. (2015). Soil carbon storage in dominant species of mangrove forest of Sarawak, Malaysia. International Journal of Physical Sciences, 2015:210-214.

Seca, G., Noraini, R., Hanafi, M.I., Ahmed OH and Ahmad M. M. P. (2015). Effects of converting tropical peat swamp forest into oil palm plantation on water quality. American Journal of Applied Sciences, 12(8):525-532.

Palanivell, P., Ahmed, O.H. Nik Muhammad Ab. Majid, Jalloh, M.B. and Susilawati, K. (2015). Improving Lowland Rice (O. sativa L. cv. MR219) Plant Growth Variables, Nutrients Uptake, and Nutrients Recovery Using Crude Humic Substances. The Scientific World Journal: TSW Soil Science, 2015:1-13.

Maryam, G., Nik Muhamad, A.M., M.M. Islam, Ahmed, O.H., and Abdu, A. (2015). Phytoremediation of copper contaminated sewage sldge by tropical plants. Journal of Tropical Forest Science, 27(4):535-547.

Rizal, A., Husni, M.H.A, Ahmed, O.H. and Hilmi, M.S. (2015). Influence of urea and ammonium sulphate on potential mineralization and nitrification in tropical peat soil from oil palm cultivation under laboratory condition. International Journal of Tropical Agriculture, 33(2):1747-1754.

Ywih, C.H., Ahmed, O.H., and Nik Muhamad, A.M. (2014). Biochar and compost influence the phosphorus availability, nutrient uptake, and growth of maize (Zea mays L.) in tropical acid soil. Pakistan Journal of Agricultural Sciences, 51(4): 797-806.

Muhamad Ismawi, S., Seca, G. and Ahmed, O.H. (2014). Effect of cultivation in different age’s oil palm plantation on selected chemical properties of peat swamp soils. Agriculture, Forestry and Fisheries, 3(1):6-9.

Palanivell, P., Ahmed, O.H. Susilawati, K and Nik Muhammad Ab. Majid. (2015). Mitigating ammonia volatilization from urea in waterlogged condition using clinoptilolite zeolite. International Journal of Agriculture and Biology. 17: 149-155.

Aainaa, H.N., Ahmed, O.H., Kasim, S. and Majid N.M.A. 2015­­. Reducing Egypt Rock Phosphate Use in Zea mays Cultivation on an Acid Soil Using Clinoptilolite Zeolite. Sustainable Agriculture Research, 4(1): 56-66.

Latifah. O. Ahmed, O.H. and Majid N.M.A. 2015­­. Improving ammonium and nitrate release from urea using clinoptilolite zeolite and compost produced from agricultural wastes. The Scientific World Journal, 1-12.

Bah, A., Husni, M.H.A., Teh, C.B.S., Rafii, M.Y., Syed Omar, S.R. and Ahmed, O.H. 2014. Reducing Runoff Loss of Applied Nutrients in Oil Palm Cultivation Using Controlled-Release Fertilizers. Advances in Agriculture, 1-9.

Ch'ng, H.Y., Ahmed, O.H., Kassim, S. and Majid N.M.A. 2014. Recycling of Sago (Metroxylon sagu) Bagasse with Chicken Manure Slurry through Co-composting. Journal of Agricultural Science and Technology, 16 (6): 1441-1454.

Lim Kim Choo, L.N. and Ahmed O.H. 2014. Partitioning Carbon Dioxide Emission and Assessing Dissolved Organic Carbon Leaching of a Drained Peatland Cultivated with Pineapple at Saratok, Malaysia. The Scientific World Journal, 1-9.

Ch'ng, H.Y., Ahmed, O.H. and Majid N.M.A. 2014. Improving Phosphorus Availability in an Acid Soil Using Organic Amendments Produced from Agroindustrial Wastes. The Scientific World Journal, 1-6.

Aainaa, H.N., Ahmed, O.H., Kasim, S. and Majid N.M.A. 2014­­. Use of Clinoptilolite Zeolite to Reduce Christmas Island Rock Phosphate use in Zea mays Cultivation on an Acid Soil. International Journal of Soil Science, 9(2): 55-66.

Aainaa, H.N., Ahmed, O.H., Kasim, S. and Majid N.M.A. 2014­­. Use of Clinoptilolite Zeolite on Selected Soil Chemical Properties, Dry Matter Production, Nutrients Uptake and Use Efficiency of Zea mays Cultivated on an Acid Soil. International Journal of Soil Science, 9(3): 136-148.

Gandaseca, S., Salimin, M.I. and Ahmed O.H. 2014. Effect of cultivation in different age’s oil palm plantation on selected chemical properties of peat swamp soils. Environment, 3(6-1): 6-9.

Hamdan, J. and Ahmed, O.H. 2013. Potassium dynamics of a forest soil developed on a weathered schist regolith. Archives of Agronomy and Soil Science, 59(4): 593-602.12. Lija, W.B.M, Ahmed, O.H. and Susilawati, K. 2014. Maize (Zea mays L.) Nutrient Use Efficiency as Affected by Formulated Fertilizer with Clinoptilolite Zeolite. Emirates Journal of Food and Agriculture, 26(3):284-292.

Abdullahi,. N., Sidik, J.B., Ahmed, O.H. and Zakariah, M.H.2014. Effect of planting methods on growth and yield of cassava (Manihot esculenta Crantz) grown with polythene-covering. Journal of Experimental Biology and Agricultural Sciences, 1(7): 481-487.

Ywih, C.H., Ahmed, O.H., and Nik Muhamad, A.M. 2013. Co-composting of pineapple pineapple leaves with chicken manure slurry. International Journal of Recycling of Organic Wastes in Agriculture, 2:25, 1-7.

Palanivell, P., Susilawati, K Ahmed, O.H. and Nik Muhammad Ab. Majid. 2013. Compost and Crude Humic Substances Produced from Selected Wastes and their Effects on Zea Mays L. Nutrient Uptake and Growth. The Scientific World Journal: TSW Soil Science. 1-15.

Wahida, N.H., Anuar, A.R., Fauziah, C.I. and Ahmed, O.H. 2013. Response of Brassica rapa var. Parachinensis Grown on copper contaminated Oxisol, Inceptisol, and Histosol. Malaysian Journal of Soil Science, 17: 99-110.

Zakry, F.A.A., Halimi, M.S., Abdul Rahim, K.B. and Ahmed, O.H.  2013. In silico Protein Prediction of the 16S ribosomal RNA Gene from Novel Rhizobacterium Bacillus cereus UPMLH24. Journal of Pure and Applied Microbiology , 7(4): In press.

Roland, K.J., Nik Muhamad, A. M., Seca, G., and Ahmed, O.H. 2013. Above Ground Biomass-carbon Partitioning, Storage and Sequestration in aRehabilitated Forest, Bintulu, Sarawak, Malaysia. Sains Malaysian, 42(8): 1041–1050.

Akbar, M.H., Arifin, A. Jusop, S.,Ahmed, O.H., Abdul-Hamid, Baharom, Z., Abdul-Latif, S., and Nasima, J. 2013. Effects of mixed organic and inorganic fertilizers on soil properties and the growth of Kenaf (Hibiscus cannabinus L.) cultivated on Briss Soils. American Journal of Applied Sciences, 10(12): 1586-1597.

Rabai, K.A., Ahmed, O.H. and Susilawati, K. 2013. Use of formulated Nitrogen, Phosphorus, and Potassium compound fertilizer using clinoptilolite zeolite in Maize (Zea mays L.) cultivation. Emirates Journal of Food and Agriculture, 25(9): 713-722.

Tang, A., Wong, S.K., Ahmed, O.H. and Majid, N.M. 2013. Cellulolytic, nitrogen-fixing and phosphate-solubilizing micro-organisms as biological indicators of forest soil rehabilitation. ASM Science Journal, 7(1): 23-26.

Roland, K.J., Nik Muhamad, A. M., Seca, G., Ahmed, O.H. Silvester, J. and Melvin, K.K.K. 2013. Assessment of floristic composition in a rehabilitated forest, Sarawak, Malaysia. Boneo Journal Of Resource Technology, 2(2):60-66.

Palanivell, P., Susilawati, K., Ahmed, O.H. and Nik Muhamad, A.M. 2013. Effects of Crude Humin and Compost Produced from Selected Wasted on Zea mays Growth, Nutrient Uptake and Nutrient Use Efficiency. African Journal of Biotechnology, 12(13): 1500-1507.

Hilmi, I.M., Susilawati, K., Ahmed, O.H. and Nik Muhamad, A.M. 2013. Effects of simulated acid rain on Shorea macroptera growth and selected soil chemical properties. African Journal of Agricultural Research, 8(15): 1280-1289.

Edward, E.J., W.S. King, S.I.C. Tech, M. Jiwan, Z.F.A. Aziz, F.R. Kundat, O.H. Ahmed and N.M. Majid. 2013. Antagonistic Activities of Endophytic Bacteria against Fusarium Wilt of Black Pepper (Piper nigrum). International Journal of Agriculture and Biology, 15: 291‒296.
Lija, W.B.M, Ahmed, O.H. and Susilawati, K. 2012. Reducing Ammonia Volatilization from Compound Fertilizers Amended With Zeolite. African Journal of Biotechnology, 11(74): 13903-13906.

Rabai, K.A., Ahmed, O.H. and Susilawati, K. 2012. Improving formulated nitrogen, phosphorus and potassium compound fertilizer using zeolite. African Journal of Biotechnology, 11(64): 12865-12829.

Hamdan, J. and Ahmed, O.H., 2012. Potassium dynamics of a forest soil developed on a weathered schist regolith. Archives of Agronomy and Soil Science, 58:1-10.

Ahmed, O.H., Rosliza, S., Susilawati, K., Nik Muhamad, A.M. and Jalloh, M.B. 2102. Effect of N, P and K Humates on Dry Matter of Zea mays and Soil pH, Exchangeable Ammonium and Available Nitrate. African Journal of Biotechnology, 11(40): 1684-5315.

Muhamad  Ismawi, S., Seca, G. and Ahmed, O.H. 2012. Effects of deforestation on soil major macro-nutrients and other selected chemical properties of a secondary tropical peat swamp forest. International Journal of the Physical Sciences, 7(14): 2225-2228.

Roland, K.J., Nik Muhamad, A. M., Seca, G., Ahmed, O.H. Silvester, J. and Melvin, K.K.K. 2012. Assessment of micrometeorology at selected age stands in a rehabilitated forest of Sarawak, Malaysia. Journal of Tropical Biology and Conservation, 9(1):83-95.

Roland, K.J., Nik Muhamad, A. M., Seca, G. and Ahmed, O.H. 2012. Estimantion of total above ground biomass at selected age stands of a rehabilitated forest. Journal of Tropical Biology and Conservation, 9(1): 164-175.

Rahamah, B.M., Khairulmazmi, A., Ahmed, O.H., Zamri, Rosli and Sariah M. 2012. In vitro effects of salicylic acid, calcium and copper ions on growth and sporulation of Ganoderma boninense. African Journal of Biotechnology, 11(70):13477-13489.

Pau, C.G., C.T.S. Leong, S.K. Wong, L. Eng, M. Jiwan, F.R. Kundat, Z.F.B.A. Aziz, O.H. Ahmed and N.M. Majid. 2012. Isolation of Indigenous Strains of Paecilomyces lilacinus withAntagonistic Activity against Meloidogyne incognita. International Journal of Agriculture and Biology, 14(12):1814–9596.

Palanivell, P., Susilawati, K., Ahmed, O.H. and Nik Muhamad, A.M. 2012. Effect of Humin-Urea-Rock Phosphate Amendment on Bekenu Series (Tipik Tualemkuts) Soil. African Journal of Biotechnology, 11(45):10317-10321.

A. Norida Hanim, A. M. Nik Muhamad, O. H. Ahmed, K. Susilawati and A. Khairulmazmi. 2012. Physico-chemical Properties of Indigenous Micro Organism-Composts and Humic Acid Prepared from Selected Agro-industrial Residues. African Journal of Biotechnology, 11(34):8456-8463.

Palanivell, P., Susilawati, K., Ahmed, O.H. and Nik Muhamad, A.M. 2012. Effects of extraction period on yield of rice straw compost humic acids. African Journal of Biotechnology, 11(20): 4530-4536.

Zakry, F.A.A., Halim, M.S., Abdul Rahim, K.B., Ahmed, O.H. and Wong, S.K. 2012. Variable responses on early development of shallot (Allium ascalonicum) and mustard (Brassica juncea) plants to Bacillus cereus inoculation. Malaysian Journal of Microbiology, 8(1):47-50.

Mohd Suffian, F., Seca, G., Ahmed, O.H. and Nik Muhamad, A.M. 2012. Comparison of selected physical properties of deep peat within different ages of oil palm plantation. International Journal of the Physical Sciences, 7(42):5711-5716.

Keen, Y.C., Jalloh, M.B. Ahmed, O.H., Sudin, M. and Awang Besar, N. 2011. Soil Organic Matter and Related Soil Properties in Forest, Grassland and Cultivated. International Journal of the Physical Sciences, 6(32):7410-7415.

Bundan, L., Nik Muhamad, A.M., Ahmed, O.H., Jiwan, M. and Kundat, F.R. 2011. Ammonia volatilization from urea at different levels of zeolite. International Journal of the Physical Sciences. 6(34): 7717-7720.

Latifah, O., Ahmed, O.H. and Nik Muhamad, A.M. 2011. Effect of Mixing Urea with Zeolite and Sago Waste Water on Nutrient Use Efficiency of Maize (Zea mays L.). African Journal of Microbiology Research, 5(21): 3462-3467.

Ywih, C.H., Ahmed, O.H., and Nik Muhamad, A.M. 2011. Assessment of Carbon storage in a tropical rehabilitated forest. International Journal of the Physical Sciences, 6(26):6210-6219.

Mohd. Taufik, M.Y., Ahmed O.H., and Nik Muhamad, A.M. 2011. Effect of Amending Urea with Humic Acids and Acid Sulphate on Biomass Production of Masmadu (Zea mays L.) and Selected Soil Chemical Properties. International Journal of the Physical Sciences, 6(20): 4690-4694.

Mohd. Taufik, M.Y., Ahmed O.H., and Nik Muhamad, A.M. 2011. Ammonia Loss Reduction, Exchangeable Ammonium and Available Nitrate Retention in Soil Treated with Urea Mixed with Humic Acid and Acid Sulphate Soil. International Journal of the Physical Sciences, 6(21): 4897-4902.

Bernard, R., Ahmed, O.H. and Nik Muhamad, A.M. 2011. Utilization of Activated Carbon Produced from Sago hampas (Metroxylon sagu) to Reduce Ammonia Loss from Urea. International Journal of the Physical Sciences, 5(25): 6140-6146.

Latifah, O., Ahmed, O.H. and Nik Muhamad, A.M. 2011. Enhancing nutrient use efficiency of maize (Zea mays L.) by mixing urea with zeolite and peat soil water. International Journal of the Physical Sciences, 6(14):3330-3335.

Mohd Suffian, F., Seca, G., Ahmed, O.H. and Nik Muhamad, A.M. 2011. Effect of drainage and land clearing on selected peat soil physical properties of a secondary peat swamp. International Journal of the Physical Sciences, 6(23): 5462-5466.

Melvin, K.K.K., Japar, S.B., Ahmed, O.H., Nik Muhamad, A.M., Roland, K.J.H. and Sylvester, J. 2011. Comparison of carbon and selected macronutrients in forest-floor litter of rehabilitated and secondary forests. American Journal of Applied Sciences, 8(10): 967-972.

Ywih, C.H., Ahmed, O.H., and Nik Muhamad, A.M. 2011. Qualitative assessment of soil carbon in a rehabilitated forest using Fourier Transfer Infrared Spectroscopy. The Scientific World Journal: TSW Environment, 11: 532-545.

Susilawati, K., Ahmed, O.H., Nik Muhamad, A.M. and Khanif, Y. 2011. Effectiveness of liquid organic-nitrogen fertilizer in enhancing nutrients uptake and use efficiency in corn (Zea mays). African Journal of Biotechnology, 10(12):2274-2281.

Latifah, O., Ahmed, O.H. and Muhamad, A.M. 2011. Ammonia loss, ammonium and available nitrate accumulation from mixing urea with zeolite and peat soil water under non-waterlogged condition. African Journal of Biotechnology, 10(17):3365-3369.

Latifah, O., Ahmed, O.H. and Muhamad, A.M. 2011. Reducing ammonia loss from urea and improving soil exchangeable ammonium and available nitrate in non waterlogged soils through mixing zeolite and sago (Metroxylon sagu) waste water. International Journal of the Physical Sciences, 6(4):866-870.

Latifah, O., Ahmed, O.H. and Muhamad, A.M. 2011. Ammonia loss, soil exchangeable ammonium and available nitrate contents from mixing urea with zeolite and peat soil water under non-waterlogged condition. International Journal of the Physical Sciences, 6(12):2916-2920.

Ahmad Shukri, M.N., Seca, G., Ahmed, O.H. and Nik Muhamad, A.M. 2011. Effect of tropical peat swamp clearing on carbon soil storage. American Journal of Agricultural and Biological Sciences, 6(1): 80-83.

Ywih, C.H., Ahmed, O.H., and Nik Muhamad, A.M. 2011. Qualitative assessment of soil carbon in a rehabilitated forest Fourier Transfer Infrared Spectroscopy. The Scientific World Journal: TSW Environment, 11: 532-545.

Susilawati, K., Ahmed, O.H., Nik Muhamad, A.M. and Khanif, Y. 2011. Effectiveness of liquid organic-nitrogen fertilizer in enhancing nutrients uptake and use efficiency in corn (Zea mays). African Journal of Biotechnology, 10(12): 2274-2281.

Latifah, O., Ahmed, O.H. and Muhamad, A.M. 2011. Reducing ammonia loss from urea and improving soil exchangeable ammonium and available nitrate in non waterlogged soils through mixing zeolite and sago (Metroxylon sagu) waste water. International Journal of the Physical Sciences, 6(4): 866-870.

Latifah, O., Ahmed, O.H. and Muhamad, A.M. 2011. Ammonia loss, ammonium and available nitrate accumulation from mixing urea with zeolite and peat soil water under non-waterlogged condition. African Journal of Biotechnology, 10(17): 3365-3369.

Roland, K.J., Nik Muhamad, A. M., Seca, G., Ahmed, O.H. Silvester, J. and Melvin, K.K.K. 2011. Forest Structure Assessment of a Rehabilitated Forest. American Journal of Agricultural and Biological Sciences, 6(2): 256-260.

Empi R., Seca, G., Ahmed, O.H. and Nik Muhamad, A.M. 2011. Comparison of selected chemical properties of two different mangrove forests in Sarawak, Malaysia. American Journal of Environmental Sciences, 6(5): 438-441.

Zakry, F.A.A., Halim, M.S., Abdul Rahim, K.B., Ahmed, O.H., Wong, S.K., Franklin, R.K., Stephen, L.C.T. and Make, J. 2010. Isolation and plant growth promoting properties of rhizobacterial diazotrophs from pepper vine (Pepper nigrum L.). Malaysia Applied Biology Journal, 39(2):41-45.

Ahmed, O.H., Sumalatha, G. and Muhamad, A.M. 2010. Use of Zeolite in maize (Zea mays) cultivation on Nitrogen, Potassium and Phosphorus uptake and use efficiency. International Journal of the Physical Sciences, 5(15): 2393-2401.

Ahmed, O.H., Braine Yap. C.H. and Muhamad, A.M. 2010. Minimizing ammonia loss from urea through mixing with zeolite and acid sulphate soil. Journal of the Physical Sciences, 5(14): 2198-2202.

Latifah, O., Ahmed, O.H. and Muhamad, A.M. 2010. Minimizing ammonia volatilization in waterlogged soils through mixing of urea with zeolite and sago waste water. International Journal of the Physical Sciences, 5(14): 2193-2197.

Ahmed, O.H., Nur Aainaa. H., and Muhamad, A.M. 2010. Accumulation of soil carbon and phosphorus contents of a rehabilitated forest. The Scientific World Journal: TSW Environment, 10: 1988-1995.

Ahmed, O.H., Nur Aainaa. H., and Muhamad, A.M. 2010. Accumulation of soil carbon and phosphorus contents of a rehabilitated forest. The Scientific World Journal: TSW Environment, 10: 1988-1995.

Mohd Suffian, S., Seca, G., Ahmed, O.H. and Nik Muhamad, A.M. 2010. Effect of converting secondary tropical peat swamp forest into oil palm plantation on selected soil physical properties. American Journal of Environmental Sciences, 6(4):402-405.

Franklin, R.K., Shen, L.H. and Ahmed, O.H. 2010. Incorporation of bentazone with Exserohilum rostratum for controlling Cyperus iria. American Journal of Agricultural and Biological Sciences, 5(2):210-214.

Muhamad Ismawi, S., Seca, G. Ahmed, O.H. and Nik Muhamad, A.M. 2010. Comparison of chemical properties of peat swamp soil before and after timber harvesting in Sarawak. American Journal of Environmental Sciences, 6(2):164-167.

Jia Huey, L., Ahmed, O.H. and Muhamad, A.M. 2010. Effects of extractants on the yields and selected chemical characteristics of humic acids isolated from tropical saprists peat. American Journal of Applied Sciences, 7(7):920-923.
89. Akbar, M.H., Ahmed, O.H., Jamaluddin, A.S., Nik Muhamad, A.M., Abdul-Hamid, H., Jusop, S., Hassan, A., Yusof, K.H. and Arifin, A. 2010. Differences in soil physical and chemical properties of rehabilitated and secondary forests. American Journal of Applied Sciences, 7(9): 1200-1209.

Saga, B.T., Ahmed, O.H., Jamaluddin, A.S., Nik Muhamad, A.M., Abdul-Hamid, H., Jusop, S., Hassan, A., Yusof, K.H. and Arifin, A. 2010. Soil morphological, mineralogical, and sesquioxide properties of rehabilitated and secondary forests. American Journal of Environmental Sciences, 6(4): 389-394.

Zuraidah, Y, Aminudin, H, Jamal, T, Jamarei, O, Ahmed, OH and Jalloh, MB. 2010. Soil compaction and oil palm (Elaeis guineensis) yield in a clay textured soil. American Journal of Agricultural and Biological Sciences (USA) 7(3): 15-19.

Zuraidah, Y, Aminudin, H, Jamal, T, Jamarei, O, Ahmed, OH and Jalloh, MB. 2010. Oil Palm (Elaeis guineensis) roots response to mechanization in Bernam Series. American Journal of Applied Sciences (USA) 7(3): 343-348.

Ameera AR, Ahmed OH, Nik Muhamad AM and Jalloh MB. 2009. Reducing ammonia loss from urea by mixing with humic and fulvic acids isolated from coal. American Journal of Environmental Sciences (USA) 5(3):420-426.

Ahmed OH, Nik Muhamad AM and Jalloh MB. 2009. Effect of grain size on selected physico-chemical properties of clay. American Journal of Environmental Sciences (USA) 5(5): 610-612.

Auldry, CP, Ahmed, OH, Nik Muhamad, AM, Mohammad Nasir H, Jiwan, M and Banta, MG. 2009. Chemical Characteristics of Compost and Humic Acid from Sago Waste (Metroxylon sagu). American Journal of Applied Sciences (USA) 6(11): 1880-1884.

Rosliza, S, Ahmed, OH, Susilawati, K, Nik Muhamad, AM and Jalloh, MB. 2009. Simple and rapid method of isolating humic acids from tropical peat soils (Saprists). American Journal of Applied Sciences (USA) 6(5): 707-710.

Leng, LY, Ahmed, OH, Nik Muhamad, AM and Jalloh, MB. 2009. Organic matter, carbon and humic acids in rehabilitated and secondary forest soils. American Journal of Applied Sciences (USA) 6(4): 711-715.

Susilawati, K, Ahmed, OH, Nik Muhamad, AM and Khanif, Y. 2009. Reduction of ammonia loss by mixing urea with liquid humic and fulvic acids isolated from tropical peat soil. American Journal of Agricultural and Biological Sciences (USA) 4(1): 18-23.

Susilawati, K, Ahmed, OH, Nik Muhamad, AM and Khanif, Y. 2009. Effect of Organic Based N Fertilizer on Dry Matter (Zea mays L.), Ammonium and Nitrate Recovery in an Acid Soil of Sarawak, Malaysia. American Journal of Applied Sciences (USA) 6(7): 1289-1294.

Ywih, CH, Ahmed, OH, Nik Muhamad, AM and Jalloh, MB. 2009. Effects of converting secondary forest on peat to oil palm plantation on carbon storage. American Journal of Agricultural and Biological Sciences (USA) 4(1): 123-130.

Chen, CHH, Ahmed, OH, Nik Muhamad, AM and Jalloh, MB. 2009. Reduction of isolation period of coal humic acids. American Journal of Applied Sciences (USA) 6(7): 1327-1330.

Rajeswari, M, Seca, G, Sabang, J, Ahmed, OH and Nik Muhamad, AM. 2009. Effect of different ages of rehabilitated forest on selected soil physico-chemical properties. American Journal of Applied Sciences (USA) 6(6): 1043-1046.

Seca, G, Sabang, J, Ahmed, OH and Nik Muhamad, AM. 2009. Vegetation assessment of peat swamp forest using remote sensing. American Journal of Agricultural and Biological Sciences (USA) 4(2): 167-172.

Auldry, CP, Ahmed, OH, Nik Muhamad, AM, Mohammad Nasir H, and Jiwan, M. 2009. Production of Potassium and Calcium Hydroxide compost humic acid from (Metroxylon sagu) waste. American Journal of Environmental Sciences (USA) 5(5): 664-668.

Rosliza, S, Ahmed, OH, Nik Muhamad, AM and Jalloh, MB 2009. Controlling ammonia volatilization and improving soil exchangeable ammonium and nitrate retention by mixing urea with humic acid, fulvic acid and triple superphosphate and muriate of potash. American Journal of Environmental Sciences (USA) 5(5): 605-609.

Mohd. Taufik, MY, Ahmed OH, and Nik Muhamad, AM. 2009. Effect of mixing urea with humic acid and acid sulphate soil on ammonia loss, exchangeable ammonium and available nitrate. American Journal of Applied Sciences (USA) 5(5): 588-591.

Mohd. Taufik, MY, Ahmed OH, and Nik Muhamad, AM. 2009. Effect of enhancing urea-humic acid mixture with refined acid sulphate soil. American Journal of Applied Sciences (USA) 6(11):1892-1896.

Anton, ES, Seca, G, Ahmed, OH and Nik Muhamad, AM. 2009. Effect of skidding operations on soil carbon storage of a tropical peat swamp forest. American Journal of Environmental Sciences (USA) 5(6): 722-726.

Anton, ES, Seca, G, Ahmed, OH and Nik Muhamad, AM. 2009. Effect of logging operation on soil carbon storage of a tropical peat swamp forest. American Journal of Environmental Sciences (USA) 5(6): 748-752.

Law, MC, Balasundram, SK, Husni, MHA, Ahmed, OH and Mohd. Hanif, H. 2009. Spatial variability of soil organic carbon in oil palm. International Journal of Soil Science: 1-11.

Anton, ES, Seca, G, Ahmed, OH and Nik Muhamad, AM 2009. Influence of chemical properties on soil carbon storage of a tropical peat swamp forest. American Journal of Applied Sciences (USA) 6(11):1970-1973.

Auldry CP, Ahmed OH, Nik Muhamad AM, Mohammad Nasir H, Jiwan M, and Banta MG. 2009. Production of Potassium and Calcium Hydroxide compost humic acid from (Metroxylon sagu) waste American Journal of Environmental Sciences (USA) 5(5): 664-668.

Zuraidah, Y, Aminudin, H, Jamal, T, Jamarei, O, Ahmed, OH and Jalloh, MB. 2009. Machinery Compaction Effects on Physical Properties of Bernam Series in an Oil Palm Plantation. American Journal of Applied Sciences (USA) 6(12): 2006-2009.

Rosliza, S, Ahmed OH, and Nik Muhamad AM. 2009. Reduction of ammonia volatilization through mixing urea with humic and fulvic acids isolated from palm oil mill effluent (POME) sludge. American Journal of Environmental Sciences (USA): 5(3) 382-386.

Regis, Bernard, Ahmed OH, and Nik Muhamad AM. 2009. Reduction of ammonia loss through mixing urea with humic acids isolated from peat soil (Saprists). American Journal of Environmental Sciences (USA): 5(3): 393-397.

Makilan M, Ahmed OH, Nik Muhamad AM and Jalloh MB. 2009. Conversion of secondary forest to oil palm plantation: Effect on total nitrogen, exchangeable ammonium, available nitrate and organic carbon storage. American Journal of Environmental Sciences (USA) 5(3): 406-412.

Anton, ES, Seca, G, Ahmed, OH and Nik Muhamad AM. 2009. Effect of precipitation fluctuation on soil carbon storage of a tropical peat swamp forest. American Journal of Applied Sciences (USA) 6(8): 1484-1488.

Jalloh, MB, Wan Sulaiman, WH, Jamal, T, Mohd Fauzi, R, Rajan, A, Christopher, TBS and Ahmed, OH 2009. A simulation model estimates of the intercropping advantage of an immature-rubber, banana and pineapple system. American Journal of Agricultural and Biological Sciences (USA) 4(3): 249-254.

Ahmed, OH, Aminuddin H, Husni MHA and Jalloh MB. 2009. Enhancing the urea-N use efficiency in maize (Zea mays) cultivation on acid soils using urea amended with Zeolite and TSP. American Journal of Applied Sciences (USA) 6(4): 553-556.

Rosliza, S, Ahmed OH, Susilawati, K, Nik Muhamad AM and Jalloh MB. 2009. Simple and rapid method of isolating humic acids from tropical peat soils (Saprists). American Journal of Applied Sciences (USA) 6(4): 654-657.

Leng, LY, Ahmed OH, Nik Muhamad AM and Jalloh MB. 2009. Organic matter, carbon and humic acids in rehabilitated and secondary forest soils. American Journal of Applied Sciences (USA) 6(4): 570-575.

Rajeswari, M., Seca, G, Sabang, J, Ahmed OH and Nik Muhamad AM. 2009. Effect of different ages of rehabilitated forest on selected soil physico-chemical properties. American Journal of Applied Sciences (USA) 6(6): 1043-1046.

Susilawati T, Ahmed OH, Nik Muhamad AM and Khanif Y. 2009. Reduction of ammonia loss by mixing urea with liquid humic and fulvic acids isolated from tropical peat soil. American Journal of Agricultural and Biological Sciences (USA) 4(1): 18-23.

Susilawati T, Ahmed OH, Nik Muhamad AM and Khanif Y. 2009. Effect of Organic Based N Fertilizer on Dry Matter (Zea mays L.), Ammonium and Nitrate Recovery in an Acid Soil of Sarawak, Malaysia. American Journal of Applied Sciences (USA) 6(6): 1282-1287.

Ywih, CH, Ahmed OH, Nik Muhamad AM and Jalloh MB. 2009. Effects of converting secondary forest on peat to oil palm plantation on carbon storage. American Journal of Agricultural and Biological Science (USA) 4(2): 123-130.

Chen, CHH, Ahmed OH, Nik Muhamad AM and Jalloh MB. 2009. Reduction of isolation period of coal humic acids. American Journal of Applied Sciences (USA) 6(7): 1327-1330.

Seca, G, Sabang, J, Ahmed OH and Nik Muhamad AM. 2009. Vegetation assessment of peat swamp forest using remote sensing. American Journal of Agricultural and Biological Sciences (USA) 4(2): 167-172.

Nur Hanisah MR, Ahmed, OH, Susilawati, K, Nik Muhamad AM and Jalloh MB. 2008. Determination of minimal duration essential for isolation of humic acids from soils in forest restoration programmes. American Journal of Agricultural and Biological Science (USA) 3(3):597-601.

Ahmed OH, Aminuddin H and Husni MHA. 2008. Evaluation of urea amended with zeolite and triple superphosphate in improving urea-N use efficiency in maize cultivation on acid soils. TheScientificWorldJOURNAL (UK) 8: 394-399.

Sharul K, Ahmed OH, Shaharudin S and Nik Muhamad AM. 2008. Gamma radiosensitivity study on chili (Capsicum annuum). American Journal of Applied Sciences (USA) 5(2):67-70.

Ahmed OH, Aminuddin H and Husni MHA. 2008. Ammonia volatilization and ammonium accumulation from urea mixed with zeolite and triple superphosphate. Acta Agriculturæ Scandinavica Section B, Soil and Plant Science (UK) 58(2): 182-186.

Susilawati T, Ahmed OH, Nik Muhamad AM and Khanif Y. 2008. Simple method of purifying humic acids isolated from tropical peat hemists (peat soil). American Journal of Applied Sciences (USA) 5(12):1812-1815.

Anuar AR, Goh, KJ, Tee BH and Ahmed OH. 2008. Spatial variability of soil inorganic N in a mature oil palm plantation in Sabah, Malaysia. American Journal of Applied Science (USA) 5(9): 1239-1246.

Anuar AR, Goh, KJ, Tee BH and Ahmed OH. 2008. Spatial-temporal yield trend of oil palm as influenced by nitrogen fertilizer management. American Journal of Applied Science (USA) 5(10):1376-1383.

Anuar AR, Goh, KJ, Tee BH and Ahmed OH. 2008. Transforming Spatio-Temporal Yield Maps to Classified Management Zone Maps for Efficient management of oil palm. American Journal of Applied Science (USA) 5(10): 1392-1396.

Balasundram SK, Husni MHA and Ahmed OH. 2008. Application of geostatistical tools to quantify spatial variability of selected soil chemical properties from a cultivated tropical peat. Journal of Agronomy (USA) 7(1): 82-87.

Balasundram SK, Husni MHA and Ahmed OH. 2008. Spatial variability of pineapple yields on tropical peat. Crop Management ((USA): In press.

Ahmed OH, Husni MHA, Hanafi MM, Anuar AR, and Syed Omar SR. 2007. Evaluation of soil applied phosphorus fertilizer use in pineapple cultivation with in situ burning of the crop’s residues on tropical peat soils. Communications in Soil and Plant Analysis (USA) 38: 1243-1254.

Susilawati T, Ahmed OH, Nik Muhamad AM and Khanif Y. 2007. Effects of extraction and fractionation period on the yield of a tropical peat (Hemists) humic acids. American Journal of Agricultural and Biological Science (USA) 2(3): 202-205.

Kevin MTS, Ahmed OH, Wan Asrina WY, Rajan A and Azham M. 2007. Towards growing Bario rice on lowland soils: A preliminary nitrogen and potassium fertilization trial American Journal of Agricultural and Biological Science (USA) 2(2): 99-105

Mohd. Taufik MY, Ahmed OH, Wan Asrina WY and Nik Muhamad AM. 2007. Effect of organic and inorganic fertilizers on nitrogen and potassium uptake and yield of sweet corn grown on an acid. American Journal of Agricultural and Biological Science (USA) 2(2): 118-122

Norfadzrin F, Ahmed OH, Shaharudin S and Abdul Rahman D. 2007. A preliminary study on gamma radiosensitivity of tomato (Lycopersicon esculentum) and okra (Abelmoschus esculentus). International Journal of Agricultural Research (USA) 2(7): 620-625

Ellyfa K, Ahmed OH, Shaharudin S and Abdul Rahman D. 2007. Gamma radiosensitivity study on snap bean (Phaseolus vulgaris). International Journal of Agricultural Research (USA) 2(9):844-848

Ellyfa K, Ahmed OH, Shaharudin S and Nik Muhamad, M. 2007. Gamma radiosensitivity study on long bean (Vigna sesquipedalis). Americanl Journal of Applied Sciences (USA). 4(12):1090-1093

Shajarutulwardah MY, Ahmed OH, Wan Asrina WY and Nik Muhamad AM. 2007. Evaluation of nitrogen and potassium uptake and efficiency of two rice varieties cultivated on an acid soil. American Journal of Agricultural and Biological Science (USA): 2(3):130-135

Ahmed OH, Anuar AR and Husni MHA. 2006. Essentials of good scientific research. Universiti Putra Malaysia Press: Serdang, Malaysia. pp 76. ISBN 983-3455-49-2 (Book)

Ahmed OH, Husni MHA and Hanafi MM. 2006. Exploring the nature of the relationships among total, extractable, and solution phosphorus in cultivated organic soils. International Journal of Agricultural Research (USA) 1(4):331-341

Ahmed OH, Aminuddin H and Husni MHA. 2006. Reducing ammonia loss and improving soil exchangeable ammonium retention from urea through mixing triple super phosphate, humic acid and zeolite. Soil Use and Management (UK) 22:315-319

Ahmed OH, Husni MHA and Hanafi MM. 2006. Phosphorus loss of phosphorus fertilizer applied to tropical peat soils in pineapple cultivation. International Journal of Soil Science (USA). 1(1):85-90

Rajpar I, Khanif YM, Ahmed OH, Sial NB and Korejol MA 2006. Effect of source and time of application of phosphatic fertilizers on wheat. American-Eurasian Journal of Agricultural and Environmental Sciences (USA).  1(2):83-85

Ahmed OH, Aminuddin H and Husni MHA. 2006. Effects of urea, humic acid, and phosphate interactions in fertilizer microsites on ammonia volatilization, and soil ammonium and nitrate contents. International Journal of Agricultural Research (USA) 1(1):25-31

Ahmed OH, Husni MHA, Hanafi MM, Syed Omar SR. and Anuar AR. 2006. Elucidating how the capacity of cultivated tropical peat soils to supply phosphorus relates to available phosphorus forms in pineapple cultivation. International Journal of Soil Science (USA) 1: 44-52

Ahmed OH, Husni MHA, Hanafi MM, Anuar AR and Syed Omar SR. 2006. Leaching losses of soil applied potassium fertilizer in pineapple cultivation on tropical peat soils in Malaysia. New Zealand Journal of Crop and Horticultural Science (New Zealand) 34: 155-162

Ahmed OH, Husni MHA, Hanafi MM, Anuar AR and Syed Omar SR. 2005. Applied K fertilizer use efficiency in pineapples grown on a tropical peat soil under residues removal. The Scientific World JOURNAL (UK) 5:42-49

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2005. Effects of extraction and fractionation time on the yield of compost humic acids. New Zealand Journal of Crop and Horticultural Science (New Zealand) 33 (2): 107-110

Ahmed OH, 2005. Determination of minimal duration necessary for the isolation of humic acid in composted pineapple leaves. Fruits, 60(2) (France): 116-120

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2004. Towards sustainable use of potassium in pineapple waste. The Scientific World JOURNAL (UK) 4:1007-1013

Ahmed OH, Husni MHA, Anuar AR, Hanafi MM and Angela EDS. 2004. A modified way of producing humic acid from pineapple leaves. Journal of Sustainable Agriculture (USA). 25(1):129-139

Husni MHA and Ahmed OH. 2003. Peatland: Use and conservation. IMPAK (Malaysia) 1:10-11

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2003. Alternative means of recycling pineapple leaf residue. Fruits (France) 58 (1): 53-59

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2003. Pineapple residues: from burning to products development. Pineapple News (USA) 10. p10

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2003. Production of humic acid from pineapple leaf residue. Journal of Sustainable Agriculture (USA): 22(1):111-124

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2003. Economic viability of pineapple residues recycling.  Journal of Sustainable Agriculture (USA) 21(4): 129-137

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2002a. Economic viability of modifying pineapple residue management practice and potassium rate in pineapple cultivation on tropical. Tropical Science (UK) 42:107-110

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2002b. Nitrogen and pineapple residue use in pineapple production. Tropical Science (UK) 42: 174-177

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2002. Effect of residue management practices on yield and economic viability of Malaysian pineapple production. Journal of Sustainable Agriculture (USA) 20 (4): 83-93.

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2002. The removal and burning of pineapple residues in pineapple cultivation on tropical peat: An economic viability comparison. Pertanika Journal of Tropical Agricultural Science (Malaysia) 25 (1): 47-51

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2001a. Some observations in pineapple production under different fertilization programmes and different pineapple residue management practices. Pertanika Journal of Tropical Agricultural Science (Malaysia) 24 (2): 115-121

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2001b. Pineapple residue management practices and fertilizer regimes: effects on P and K uptake, yield, and some economic implications. Pertanika Journal of Tropical Agricultural Science (Malaysia) 24 (2): 123-129

Ahmed OH, Husni MHA, Anuar AR and Hanafi MM. 2001. Recent scenarios in pineapple residue management on tropical peat. Agro Search (Malaysia) 8 (1): 15-17

Ahmed OH, Husni MHA, Syed Omar, Hanafi MM and Koh SK 2000. Macronutrients distribution and cycling of pineapple planted on tropical peat. Pertanika Journal of Tropical Agricultural Science (Malaysia) 23 (2):89-95

Ahmed OH, Husni MHA, Syed Omar SR, Hanafi MM and Koh SK 1999. The effects of residue management practices on phosphorus and potassium uptake in pineapple. Malaysian Journal of Soil Science (Malaysia) 3: 29-37

Ahmed OH, Husni MHA, Syed Omar SR, Hanafi MM and Awang Noor AG. 1999. Nutrients uptake and cycling of pineapple planted on tropical peat. Agro-Search (Malaysia) 6(1) 47-48

Ahmed OH, and Husni MHA. 1997. Dry matter production from pineapple parts   planted on tropical peat. Agro-Search (Malaysia) 4(1) 25-26

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