Prof. Dr. Paul L. G. Vlek

Additional Information:

Dr. Paul L.G. Vlek, emeritus professor at the University of Bonn since 2015, was the founding Executive Director of the West African Science Service Center on Climate Change and Adapted Land Use (WASCAL) from 2010 till 2014, and Director/Professor for Ecology and Natural Resources Management, Center for Development Research (ZEF) at the University of Bonn (1998 -2015). Trained as a Tropical Soil Scientist at the University of Wageningen in the Netherlands and Colorado State University in the USA, he conducted research on the sustainable use of natural resources in the tropics and how this is affected by or affects development processes. Prior to his retirement Prof. Vlek also served as professor of Tropical Agronomy at the University of Goettingen (1990-1998) and founding director of the International Center for Soil Fertility Research in Togo (1987-1990). With over 200 peer- reviewed publications, Dr. Vlek is a fellow of the National Academy of Agricultural Sciences of India and the American Society of Agronomy, Soil Science Society of America as well as the Academy of Arts and Sciences of North Rhine -Westphalia, Germany. He was recipient of the GCHERA World Agricultural Prize (2014). He was editor in chief of Nutrient Cycling in Agroecosystems for over 20 years and served on several other editorial boards and national and international committees. His current residence is in Austin, Texas, USA.

2018

MacCarthy, D.S., W.A. Agyare and P.L.G. Vlek.  2018.  Evaluation of soil properties of the Sudan Savannah ecological zone of Ghana for crop production.  Ghana Jnl Agric. Sci., 52 : 95-104 . Download [PDF]
Stevenson, J. R. and Vlek, P. 2018.  2018.  Assessing the Adoption and Diffusion of Natural Resource Management Practices: Synthesis of a New Set of Empirical Studies..  Further Information

2017

Sanfo, S., B. Barbier, I.W.P. Dabiré, P.L.G. Vlek, W.M. Fonta, B. Ibrahim and B. Barry.  2017.  Rainfall variability adaptation strategies: An ex-ante assessment of supplemental irrigation from farm ponds in southern Burkina Faso.  Agricultural Systems, 152 : 80-89 . Further Information
Vlek, P.L.G., A. Khamzina A and L. Tamene.  2017.  Land degradation and the Sustainable Development Goals: Threats and potential remedies.  CIAT Publication No. 440. International Center for Tropical Agriculture (CIAT), Nairobi, Kenya. Further Information
Vlek, P.L.G., Khamzina, A., H. Azadi, A. Bhaduri, K. Bharati, A. Braimoh, C. Martius, T. Sunderland and F. Taheri..  2017.  Trade-Offs in Multi-Purpose Land Use under Land Degradation.  Sustainability, 9, doi:10.3390/su9122196 . Further Information

2013

Devkota K.P., A. Manschadi, J.P.A. Lamers , M. Devkota and P.L.G. Vlek.  2013.  Mineral nitrogen dynamics in irrigated rice–wheat system under different irrigation and establishment methods and residue levels in arid drylands of Central Asia.  European Journal of Agronomy, 47 : 65-76 .

2012

Akramkhanov, A. and P. L. G. Vlek.  2012.  The assessment of spatial distribution of soil salinity risk using neural network.  Environmental Monitoring and Assessment, 184:4 : 2475-2485 .
Djumaeva D., J.P.A. Lamers, C. Martius and P.L.G. Vlek.  2012.  Chlorophyll meters for monitoring foliar nitrogen in three tree species from arid Central Asia.  Journal of Arid Environments, 85 : 41-45 . Further Information
Khamzina A., J.P.A. Lamers and P.L.G. Vlek.  2012.  Conversion of degraded cropland to tree plantations for ecosystem and livelihood benefits.  In: Martius C., Rudenko I., Lamers J.P.A. and P.L.G. Vlek (eds.): Cotton, Water, Salts and Soums - Economic and Ecological Restructuring in Khorezm, Uzbekistan. Springer Science.  235-248. 
Kihara, J., C. Martius, A. Bationo, M. Thuita, D. Lesueur, L. Herrmann, W. Amelung and P.L.G. Vlek.  2012.  Soil aggregation and total diversity of bacteria and fungi in various tillage systems of sub-humid and semi-arid Kenya.  Applied Soil Ecology , 58 : 12-20 .
Naab, J., A. Bationo, B.M. Wafula, P.S. Traore, R. Zougmore, M. Ouattara, R. Tabo, and P.L.G. Vlek.  2012.  African Perspectives on Climate Change and Agriculture: Impacts, Adaptation, and Mitigation Potential.  In: Hillel, D., and C. Rosenzweig (eds.): ICP Series on Climate Change Impacts, Adaptation, and Mitigation Vol. 2. Imperial College Press.  85-106. 
Tesfahunegn, G.B., P.L.G. Vlek and L. Tamene.  2012.  Management strategies for reducing soil degradation through modeling in a GIS environment in northern Ethiopia catchment.  Nutr. Cycl. Agroecosyst., 92:3 : 255-272 .
Tesfahunegna G.B., L. Tamene and P.L.G. Vlek.  2012.  Modeling soil erosion by water using SWAT in northern Ethiopia.  East African Journal of Science and Technology, 2 : 1-28 .

2011

Amegashi, B.K., C. Quansah, W.A. Agyare, L. Tamene, P.L.G. Vlek.  2011.  Sediment-bound nutrient export from five small reservoir catchments and its implications for the Sudan savanna zone of Ghana.  Lakes & Reservoirs: Research & Mangement, 16 : 61-76 .
Conrad C., R.R. Colditz, S. Dech, D. Klein, P.G.L. Vlek.  2011.  Temporal segmentation of MODIS time series for improving crop classification in Central Asian irrigation systems.  International Journal of Remote Sensing, 32:23 : 8763-8778 . Further Information
Khamzina, A., J.P.A. Lamers and P.L.G. Vlek.  2011.  Summary results of long-term studies on afforestation-based land reclamation in Uzbekistan.  UNCCD book "Combating desertification and land degradation: Proven practices from Asia and the Pacific".  
Kihara, J., A. Bationo, D.N. Mugendi, C. Martius and P.L.G. Vlek.  2011.  Conservation tillage, local organic resources and nitrogen fertilizer combinations affect maize productivity, soil structure and nutrient balances in semi-arid Kenya.  Nutr. Cycl. Agroecosyst., 90 : 213-225 . Further Information
Kihara, J., C. Martius, A. Bationo and P.L.G. Vlek.  2011.  Effects of tillage and crop residue application on soybean nitrogen fixation in a tropical ferralsol.  Agriculture 2011, 1 : 22-37 .
Lulseged, T., A. Abegaz, E. Aynekulu,K. Woldearegay and P.L.G. Vlek.  2011.  Estimating sediment yield risk of reservoirs in northern Ethiopia using expert knowledge and semi-quantitative approaches.  Lakes & Reservoirs: Research & Mangement, 16 : 293 .
Mekuria, A., P.L.G. Vlek and M. Denich.  2011.  Application of the Caesium-137 technique to soil degradation studies in the southwestern highlands of Ethiopia.  Land Degradation & Development, 23:5 : 456 . Further Information
Oguntunde, Ph.G., A.E. Ajayi, J. Friesen, N. van de Giesen and P.L.G. Vlek.  2011.  Seasonal Variation of Temporal Patterns of Water Flux in a Cashew Orchard under Sub-humid Tropical Conditions.  Journal of Crop Improvement, 25 : 504–520 .
Tesfahunegn, G.B., L. Tamene and P.L.G. Vlek.  2011.  A participatory soil quality assessment in Northern Ethiopia's Mai-Negus catchment.  Catena, 86 : 1-13 . Further Information
Tesfahunegn, G.B., L. Tamene and P.L.G. Vlek.  2011.  Evaluation of soil quality identified by local farmers in Mai-Negus catchment, Northern Ethiopia.  Geoderma, 163 : 209-218 . Further Information
Tesfahunegn, G.B., L. Tamene and P.L.G. Vlek.  2011.  Catchment-scale spatial variability of soil properties and implications on site-specific soil management in northern Ethiopia.  Soil & Tillage Research, 117 : 124–139 . Further Information
Tischbein, B., A.M. Manschadi, A.K. Hornidge, C. Conrad, J.P.A. Lamers, L. Oberkircher, G. Schorcht and P.L.G. Vlek.  2011.  Ansaetze fuer ein effiziente Wassernutzung in der Provinz Khoresm, Usbekistan. (Proposals for a more efficient utilization of water resources in the Province of Khoresm, Uzbekistan).  Hydro- und Wasserwirtschaft, 55 : 116-125 .
Vlek, P.L.G., A.M. Manschadi, and J.P.A. Lamers.  2011.  Ökonomische und ökologische Umstrukturierung der Land- und Wassernutzung in der Region Khorezm (Usbekistan) – Ein Pilotprojekt in der Entwicklungsforschung.  IWRM. Integriertes Wasserressourcen-Management: Von der Forschung zur Umsetzung. Leipzig, Magdeburg.  26-27. 

2010

Djumaeva, D., J.P.A. Lamers, C. Martius, A. Khamzina and P.L.G. Vlek.  2010.  Quantification of symbiotic nitrogen fixation by Elaeagnus angustifolia L. on salt-affected irrigated croplands using two 15N isotopic methods.  Nutr. Cycl. Agroecosyst., 88 : 329-339 . Further Information
Djumaniyazova Y., R. Sommer, N. Ibragimov, J. Ruzimov, J. Lamers and P. Vlek.  2010.  Simulating water use and N response of winter wheat in the irrigated floodplains.  Field Crops Research, 116 : 239-251 .
Feitosa F., Q.B. Le and P.L.G. Vlek.  2010.  Multi-agent simulator for urban segregation (MASUS): A tool to explore alternatives for promoting inclusive cities computers, environment and urban systems.  Further Information
Le, Q.B., S.J. Park and P.L.G. Vlek.  2010.  Land Use Dynamic Simulator (LUDAS): a multi-agent system model for simulating spatio-temporal dynamics of coupled human–landscape system. 2-. Scenario-based application for impact assessment of land-use policies.  Ecological Informatics , 5:3 : 203-221 .
MacCarthy, D.S., Paul L.G. Vlek, A. Batiano, R. Tabo and M. Fosu.  2010.  Modeling nutrient and water productivity of sorghum in smallholder farming systems in a semi-arid region of Ghana.  Field Crops Res. , . Further Information
Mondal, Md. A.H., M. Denich and P.L.G. Vlek.  2010.  The future choice of technologies and co-benefits of CO2 emission reduction in Bangladesh power sector.  Further Information
Nyarko, B.K., D.K. Essumang, M.J. Eghan, B. Reichert, N. van de Giesen and P.L.G. Vlek.  2010.  Use of isotopes to study floodplain and wetland and river flow interaction in the White River Volta Basin, Ghana.  Isotopes in Environmental Health Studies , 46 : 91-106 .
Villamor, G., B. M. van Noordwijk, Q. B. Le, B. Lusiana, R. Matthews and P.L.G. Vlek.  2010.  Diversity deficits in modeled landscape.  : 1-10 . Further Information

2009

Adwubi, A., B.K. Amegashie, W.A. Agyare, L. Tamene, S. Nii Odai, C. Quansah and P.L.G. Vlek.  2009.  Assessing sediment inputs to small reservoirs in Upper East Region, Ghana.  Lakes & Reservoirs, 14 : 279-287 .
Barthlott, W., J. Szarzynski, P. Vlek, W. Lobin and N. Korotkova.  2009.  A torch in the rain forest: thermogenesis of the Titan arum (Amorphophallus titanum).  Plant Biology, 11(4) : 499-505 .
Djumaeva, D., N. Djanibekov, P.L.G. Vlek, C. Martius and J.P.A. Lamers.  2009.  Options for optimizing dairy feed rations with foliage of trees grown in the irrigated drylands of Central Asia.  Journal of Agricultural and Biological Sciences, 5(5) : 698-708 .
Fatondji, D., C. Martius, C.L. Bielders, S. Koala, P.L.G. Vlek and R. Zougmore.  2009.  Decomposition of organic amendment and nutrient release under the zai technique in the Sahel.  Nutrient Cycling in Agroecosystems, 85(3) : 225-239 .
Forkutsa, I., R. Sommer, Y.I. Shirokova, J.P.A. Lamers, K. Kienzler, B. Tischbein, C. Martius and P.L.G. Vlek.  2009.  Modeling irrigated cotton with shallow groundwater in the Aral Sea Basin of Uzbekistan.  II. Soil salinity dynamics Irrig Sci, 27 (4) : 319-330 .
Forkutsa, I., R. Sommer, Y.I. Shirokova, J.P.A. Lamers, K. Kienzler, B. Tischbein, C. Martius and P.L.G. Vlek.  2009.  Modeling irrigated cotton with shallow groundwater in the Aral Sea Basin of Uzbekistan: I. Water dynamics.  Water dynamics Irrig Sci, 27 (4) : 331-346 .
Khamzina, A., J.P.A. Lamers and P.L.G. Vlek.  2009.  Nitrogen fixation by Eleagnus angustifolia L. in the reclamation of degraded croplands of Central Asia.  Tree Physiology, 29 : 799-808 .
Khamzina, A., R. Sommer, J.P.A. Lamers and P.L.G. Vlek.  2009.  Transpiration and early growth of tree plantations established on degraded cropland over shallow saline groundwater table in northwest Uzbekistan.  Agricultural and Forest Meteorology, 11 : 1865-1874 .
Mc Carthy, D.S., R. Sommer and P.L.G. Vlek.  2009.  Modeling the impacts of contrasting nutrient and residue management practices on grain yield of sorghum (Sorghum bicolor (L.) Moench) in a semi-arid region of Ghana using APSIM.  Field Crops Res., 113 (2) : 105-115 .
Park, S.J., G.R. Rüecker, W.A. Agyare, A. Akramhanov, D. Kim and P.L.G. Vlek.  2009.  Influence of grid cell size and flow routing algorithm on soil-landform modeling.  Journal of the Korean Geographical Society, 44 (2) : 122-145 .

2008

Ajayi, A.E., N. van de Giesen and P.L.G. Vlek.  2008.  A numerical method for simulating Hortonian overland flow on tropical hillslopes with vegetation elements.  Hydrological Processes, 22 : 1107-1118 .
Akramkhanov, A., R. Sommer, C. Martius, J.M.H. Hendrickx and P.L.G.Vlek.  2008.  Comparison and sensitivity of measurement techniques for spatial distribution of soil salinity.  Irrigation and Drainage Systems, 22 : 115-126 .
Brunner A.C., S.J. Park, G.R. Ruecker and P.L.G. Vlek.  2008.  Erosion modelling approach to simulate the effect of land management options on soil loss by considering catenary soil development and farmers perception.  Land Degradation Development, 19 : 623-635 .
Cattanio, J.H., R. Kuehne and P.L.G. Vlek.  2008.  Organic material decomposition and nutrient dynamics in a mulch system enriched with leguminous trees in the Amazon.  Revista Brasileira de Ciência do Solo, 32:3 : 1073-1086 .
Compaoré, H., J.M.H. Hendrickx, S.-H. Hong, J. Friesen, N. van de Giesen, C. Rodgers, J. Szarzynski and P.L.G. Vlek.  2008.  Evaporation mapping at two scales using optical imagery in the White Volta Basin, Upper East Ghana.  Physics and Chemistry of the Earth , 33 : 127-140 .
Khamzina, A., J.P.A. Lamers and P.L.G. Vlek.  2008.  Tree establishment under deficit irrigation on degraded agricultural land in the lower Amu Darya river region, Aral Sea basin.  Forest Ecology and Management, 255 : 168-178 .
Mdemu, M.V., C. Rodgers, P.L.G. Vlek and J.J. Bogardi.  2008.  Water productivity (WP) in reservoir irrigated schemes in the upper east region (UER) of Ghana.  Physics and Chemistry of the Earth, 34 : 9 .
Ruecker, G., A. Brunner, S. Park and P.L.G. Vlek.  2008.  Assessment of soil redistribution on two contrasting hillslopes in Uganda using Caesium-137 modelling.  Erdkunde - Archive for Scientific geography, 62:3 : 18-45 .
Sommer R., K. Kienzler, C. Conrad, N. Ibragimov, J. Lamers, C. Martius and P. Vlek.  2008.  Evaluation of the CropSyst model for simulating the potential yield of cotton.  Agronomy for Sustainable Development, 28:2 : 345 .
Vlek, P.L.G.  2008.  The incipient threat of land degradation.  Journal of the Indian Society of Soil Science, 56:1 : 1-13 .
Vlek, P.L.G., D. Hillel and A.K. Braimoh.  2008.  Soil degradation under irrigation..  In: A.K. Braimoh and P.L.G. Vlek (eds.): Land Use and Soil Resources. Springer Science 7 Business Media B.V. Dordrecht.  101-119. 

2007

Agyare, W.A., S.J. Park and P.L.G. Vlek.  2007.  Artificial neural network estimation of saturated hydraulic conductivity.  Vadoze Zone Journal, 6 : 423-431 .
Anhar, A., Sommer, R., Becker, M. and P.L.G. Vlek.  2007.  The isotope 15N enrichment technique to measure the biological nitrogen fixation in cacao agroforestry system in Central Sulawesi Indonesia.  Agrista, : 54-59 .
Bharati, L., C. Rodgers, S. Shumilov, M. Plotnikova and P.L.G. Vlek.  2007.  Integrated modelling of conjunctiv use of surface and groundwater resources in a small scale irrigation system in the Volta Basin, Africa.  IAHS Publ., 317 : 167-172 .
Fosu, M., R.F. Kuehne and P.L.G. Vlek.  2007.  Mineralization and microbial biomass dynamics during decomposition of four leguminous residues.  Journal of Biological Sciences, 7:4 : 632-637 .
Hafeez M.M., B.A.M. Bouman, N. Van De Giesen, S. Mushtaq, P.L.G. Vlek and S. Khan.  2007.  Water re-use and cost-benefit of pumping at different spatial levels in a rice irrigation system in UPRIIS, Philippines.  Journal of Physics and Chemistry of the Earth, 33 : 115-126 .
Hafeez M.M., B.A.S. Bouman, N. Van De Giesen, and P.L.G. Vlek.  2007.  Scale effects on water use and water productivity in a rice-based irrigation system (UPRIIS) in the Philippines.  Journal of Agricultural Water Management, 92 : 81-89 .
Shi, Z., G.R. Ruecker, M. Mueller, C. Conrad, N. Ibragimov, J.P.A. Lamers, C. Martius, G. Strunz, S. Dech and P.L.G. Vlek.  2007.  Modeling of Cotton Yields in the Amu Darya River Floodplains of Uzbekistan Integrating Multitemporal Remote Sensing and Minimum Field Data.  Agronomy Journal, 99 : 1317–1326 .
Tamene, L. and P.L.G. Vlek.  2007.  Assessing the potential of changing land use for reducing soil erosion and sediment yield of catchments: a case study in the highlands of northern Ethiopia.  Soil Use and Management, 23 : 82-91 .
Van de Giesen, N., C. Rodgers and P.L.G. Vlek.  2007.  The GLOWA Volta Project: Interdisciplinary analysis oft he impact of global change on a river basin in West Africa.  International Journal of River Basin Management, 5:1 : 3-8 .

2006

Kaizzi, C.K., H. Ssali and P.L.G. Vlek.  2006.  Differential use and benefits of Velvet bean (Mucuna pruriens var. utilis) and N fertilizers in maize production in contrasting agro-ecological zones of E. Uganda.  Agric. Systems, 88 : 44-60 .
Khamzina, A., J.P.A. Lamers, Chr. Martius, M. Worbes and P.L.G. Vlek.  2006.  Potential of nine multipurpose tree species to reduce saline groundwater tables in the lower Amu Darya river region of Uzbekistan. Agroforestry Systems. 
Tamene, L., S.J. Park, R. Dikau and P.L.G. Vlek.  2006.  Analysis of factors determining sediment yield variability in the highlands of northern Ethiopia.  Geomorphology, 76 : 76-91 .
Tamene, L., S.J. Park, R. Dikau, and P.L.G. Vlek.  2006.  Reservoir siltation in the semi-arid highlands of northern Ethiopia: sediment yield-catchment area relationship and a semi-quantitive approach for predicting sediment yield.  Earth Surface Processes and Landforms, 31 : 1364 – 1383 .
Vlek, P.L.G. and F.W. Gatzweiler..  2006.  Can we walk the "Middle Path" in coping with global environmental change?. 

2005

Denich, M., P.L.G. Vlek, T. de Abreu Sá, K. Viehauer and W. Lücke.  2005.  A concept for the development of fire-free fallow management in the Eastern Amazon, Brazil.  Agriculture, Ecosystems & Environment, 110 (1-2) : 43-58 .
Hillel, D. and P. Vlek.  2005.  The sustainability of irrigation..  Advances in Agronomy, 87 : 55-84 .
Mitra, S., R. Wassmann and P.L.G. Vlek.  2005.  An appraisal of global wetland and its organic carbon stock.  Current Science, 88 (1) : 25-35 .
Park, S.J., C.S. Hwang and P.L.G. Vlek.  2005.  Comparison of adaptive techniques to predict crop yield response under varying soil and land management conditions.  Agricultural Systems, 85(1) : 59-81 .
Ryan, J., P. Vlek and R. Paroda.  2005.  Agriculture in Central Asia: Research for Development.  ICARDA and ZEF.

2004

Braimoh, A.K. and P.L.G. Vlek.  2004.  Land-cover change analyses in the Volta Basin of Ghana. Earth Interactions 8. Paper 21. 
Brunner, A.C., S. J. Park, G.R. Ruecker, R. Dikau and P.L.G. Vlek.  2004.  Catenary soil development influencing erosion susceptability along a hilslope in Uganda.  CATENA, 58 : 1-22 .
Fosu, M., R.F. Kühne and P.L.G. Vlek.  2004.  Improving maize yield in the Guinea Savannah zone of Ghana with leguminous cover crops and PK fertilization.  Journal of Agronomy, 3(2) : 115-121 .
Gehring, Chr. and P.L.G. Vlek.  2004.  Limitations of the 15N natural abundance method for estimating biological nitrogen fixation in Amazonian forest legumes.  Basic and Applied Ecology, 5 : pp. 567-580 .
Kaizzi, C.K., H. Ssali and P.L.G. Vlek.  2004.  The potential of Velvet bean (Mucuna pruriens) and N fertilizers in maize production on contrasting soils and agro-ecological zones of East Uganda.  Nutr. Cycling in Agroecosyst, 68 : 59-72 .
Martius, C., J. Lamers, M. Ibrakhimov, P.L.G. Vlek.  2004.  Towards a sustainable use of natural resources in the Aral Sea.  In: H. Bogena, J-F. Hake, H. Vereecken (eds.): Water and Sustainable Development. Schriftendes Forschungzentrums Julich. Reihe Umwelt/Environment (48).  117-134. 
Martius, Chr. J. Lamers, P. Wehrheim, A. Schoeller-Schletter, R. Eschanov, A. Tupitsa, A. Khamzina, A. Akramkhanov and P.L.G. Vlek.  2004.  Developing sustainable land and water management fort he Aral Sea Basin through an interdisciplinary approach.  In: Vang Seng, Eric Craswell, Shu Fukai and Ken Fischer (eds.): Water in Agriculture. ACIAR Proceedings 116, Canberra, Australia. 
Oguntunde, P.G., N.C. van de Giesen, P.L.G. Vlek and H. Eggers.  2004.  Water flux in a Cashew orchard during a wet-to dry transition period: Analysis of sap flow and eddy correlation measurements.  Earth Interactions, 8 (15) : 1-17 .
Vlek, P.L.G., G. Rodríguez-Kuhl and R. Sommer.  2004.  Energy use and CO2 production in tropical agriculture amd means and strategies for reduction or mitigation.  Environment, Development and Sustainability, 6 (1-2) : 213-233 .

2003

Bationo, A., U. Mokwunye, P.L.G. Vlek, S. Koala and B.I. Shapiro.  2003.  Soil fertility management for sustainable land use in the West African Sudano-Sahelian Zone.  In: Gichuru, M. P., A. Bationo, M. A. Bekunda, H. C. Goma, P. L. Mafongonya, D. N. Mugendi, H. M. Murwira, S. M. Nandwa, P. Nyathi, P. and M.J. Swift (eds.): Soil fertilkity management in Africa: A regional perspective. Academic Science Publishers, African Academy of Sciences, Nairobi, Kenya. 
Gorfu, A., R.F. Kuehne, D.G. Tanner and P.L.G. Vlek.  2003.  Recovery of 15N-labelled urea applied to wheat (Triticum aestivum L.) in th Ethiopian highlands as affected by P fertilization.  J. Agronomy & Crop Science, 189 : 30 – 38 .
Somado, E. A., M. Becker, R. Kühne, K. L. Sahrawat, P.L.G. Vlek.  2003.  Combined effects of legumes with phosphate rock on rice in West Africa.  Agron. J., 95 : 1172-1178 .
Somado, E. A., M. Becker, R. Kühne, K. L. Sahrawat, P.L.G. Vlek.  2003.  Rock-P effects on biomass and nitrogen accumulation by legumes in upland crop production systems of humid West Africa.  Journal of Plant Nutrition and Soil Science (submitted), .
Vlek, P.L.G. and C. Martius.  2003.  Rettung für die Aralsee-Region?. 

2002

Gole., T.W., M. Denich, D. Teketay and P.L.G. Vlek.  2002.  Human impact on the Coffea arabica genepool in Ethiopia and the need for its in situ conservation.  In: Engels, Rao, Brown and Jackson (eds.): Managing plant genetic diversity. CAB International.  Ch 23: 237- 247. 
Manske, G.G.B. and P.L.G. Vlek.  2002.  Root architecture – Wheat as a model plant.  In: Y Waisel, A. Eshel, and U. Kafkafi (eds.): Plant roots, the hidden half. Marcel Dekker, Inc. New Yok-Basel.  pp. 249-259. 
Somado, E.A., R.F. Kuehne, M. Becker, K.L. Sahrawat and P.L.G. Vlek.  2002.  Improving phosphate rock solubility and uptake and yield of lowland rice grown on an acidic soil amanded with legume green manure.  In: Vanlauwe et al (eds.): Integrated plant nutrient management in Sub-saharan Africa: From concept to Practice. CABI Publishing, Wallingford, U.K.  251-263. 
Vlek, P.L.G., U. Eberhardt, U. and M-M. Aung.  2002.  The role of Azolla in lowering the pH of simulated floodwater.  Journal of Applied Biology, 76 : 1-7 .

2001

Manske G.G.B., J.I. Ortiz-Monasterio and P.L.G. Vlek.  2001.  Techniques for measuring genetic diversity in roots.  In: Reynolds et al. (eds.): Application of Physiology in Wheat Breeding. CIMMYT; Mexico.  pp. 208-218. 
Manske. G.G.B., J.I. Ortiz-Monasterio, M. van Ginkel, R:M. González, R.A. Fischer, S. Rajaram and P.L.G. Vlek.  2001.  Importance of P uptake efficiency versus P utilization for wheat in acid and calcareous soils in Mexico.  European J. Agron, 14 : 261 – 274 .
Martius. C., H. Tiessen, and P.L.G. Vlek.  2001.  The management of organic matter in tropical soils: what are the priorities?.  Nutrient Cycl. In Agroecosystems, 61 : 1–6 .
Sommer. R., T.D.A. de Sá, K. Vielhauer, P.L.G. Vlek and H. Foelster.  2001.  Water and nutrient balance under slash-and-burn agriculture in the Eastern Amazon, Brazil – The role of deep rooting fallow vegetation.  In: Horst et al (eds.): Plant nutrition – Food security and sustainability of agr-ecosystems. Kluwer Sci. Publ. Dordrecht Netherlands.  1014-1015. 
Van de Giesen, N., M. Andreini, A. van Edig and P.L.G. Vlek.  2001.  Competition for water resources of the Volta basin. Regional Water Managm. of Water Res.  IAHS Publ no 268. (Books no 268)
Vlek, P.L.G., D. Hillel, J.C. Katyal and W. Seiler.  2001.  Water deficiency and desertification.  In: Ehlers and Krafft (eds.): Understanding the Earth System. Springer Berlin,Germany.  275 – 279. 
Vlek, Paul L.G., D. Hillel and S. Teimann.  2001.  Land Degradation: Causes and Prevention.  In: Virchow and Von Braun (eds.): Villages in the Future. Springer Verlag, Berlin.  Ch. 25: 169-171. 

2000

Bationo, A., S. P. Wani, C. L. Bielders, P. L. G. Vlek and A. U. Mokwunye.  2000.  Crop Residue and Fertilizer Management to Improve Soil Organic Carbon Content, Soil Quality and Productivity in the Desert.  In: R. Lal, H. Eswaran, J. M. Kimble and B. A. Stewart (eds.): Global climate change and tropical ecosystems. Lewis Publishers CRC pressBoca Raton, Fl.USA. 
Gorfu, A., R.F. Kuehne, D.G. Tanner and P.L.G. Vlek.  2000.  Biological nitrogen fixation in Faba bean (Vicia faba L.) in the Ethiopian highlands as affected by P fertilization and inoculation.  Biol. Fert. Soil, 32 : 1-7 .
Manske, G.G.B., J.I. Ortiz-Monasterio, M. van Ginkel, R.M. González, S. Rajaram, E. Molina and P.L.G. Vlek.  2000.  Traits associated with improved P-uptake efficiency in CYMMIT’s semidwarf spring bread wheat grown on an acid Andisol in Mexico.  Plant Soil, 221(2) : 189-204 .
Sommer, R., M. Denich and P.L.G. Vlek.  2000.  Carbon storage and root penetration in deep soils under small-farmer land-use systems in the Eastern Amazon region, Brazil.  Plant Soil, 219 : 231-240 .

1999

Egle, K., G. Manske, W. Roemer and P.L.G. Vlek.  1999.  Improved phosphorus efficiency of three new wheat genotypes from CIMMYT in comparison with an older Mexican variety.  J. Plant Nutr. Soil Sci., 162 : 353-358 .
Kato, M.S.A ., O.R. Kato, M. Denich and P.L.G. Vlek.  1999.  Fire-free alternatives to slash-and-burn for shifting cultivation in the eastern Amazon region: the role of fertilizers.  Field Crops Research, 62 : 225-237 .
Kühne, R.F., P. Vlek and H. Tiessen.  1999.  Maintaining soil quality in tropical cropping systems.  Mitt.Ges.Pflanzenbauwiss., 12 : 11-16 .
Mandal, B., P.L.G. Vlek and L.N. Mandal.  1999.  Beneficial effects of blue-green algae and Azolla, excluding supplying nitrogen, on wetland rice fields: a review.  Biology & Fert. of Soils, 28 : 329-342 .

1998

Bationo, A., and P.L.G. Vlek.  1998.  The Role of Nitrogen Fertilizers Applied to Food Crops in the Sudano-Sahelian Zone of West Africa.  In: Renard, G., Neef, A., Becker, K. and von Oppen, M. (eds.): Soil Fertility Management in West African Land Use Systems. Proc. Regional Workshop Univ. Hohenheim, ICRISAT Sahelian Centre and INRAN 4-8 March 1997, Niamey, Niger. Margraf, Weikersheim.  41-51. 
Sanetra, C.M., O. Ito, S.M. Virmani, and P.L.G. Vlek.  1998.  Remobilization of nitrogen from senescing leaves of pigeonpea (Cajanus cajan (L.) Millsp.): genotypic differences across maturity groups.  J. Exp. Bot., 49 (322) : 853-862 .
Wick, B., R.F. Kühne, and P.L.G. Vlek.  1998.  Soil microbiological parameters as indicators of soil quality under improved fallow management systems in south-western Nigeria.  Plant and Soil, 202, 1998 : 97-107 .

1997

Vlek, P.L.G., R.F. Kühne, and M. Denich.  1997.  Nutrient resources for crop procution in the tropics.  Phil. Trans. R. Soc. Lond., B 352 : 975-985 .
Wiesenmüller, J., M. Denich, and P.L.G. Vlek.  1997.  Bedeutung des Wurzelsystems für die Regeneration der Brachevegetation in Nordost-Brasilien. (Significance of the root system for the regeneration of the fallow vegetation on N. E. Brazil).  In: W. Merbach (eds.): Rhizosphärenforschung, Umweltstreß und Ökosystemstabilität. B.G. Teubner Verlagsges. Stuttgart.  84-89. 

1996

Edi Premono, M., A.M. Moawad, and P.L.G. Vlek.  1996.  "Effect of phosphate-solubilizing Pseudomonas putida on the growth of maize and its survival in the rhizosphere".  Indones. J. Crop Sci., 11 (1) : 13-23 .
Vlek, P.L.G., A.B. Lüttger, and G.G.B. Manske.  1996.  The Potential Contribution of Arbuscular Mycorrhiza to the Development of Nutrient and Water Efficient Wheat.  In: Tanner, D.G., Payne, T.S., and Abdalla, O.S. 1996 (eds.): The Ninth Regional Wheat Workshop for Eastern, Central and Southern Africa. Addis Ababa, Ethiopia: CIMMYT.  28-46. 

1995

Diekmann, U., M. Denich, and P.L.G. Vlek.  1995.  Characterization of Soil Microbiological Processes in Different Phases of the Cultivation System (Slash-and-Burn) in the Bragantina Zone of the State of Pará, Brazil.  In: J.A. Parrotta, and M. Kanashiro (eds.): Management and Rehabilitation of Degraded Lands and Secondary Forests in Amazonia. Proc. Intern. Symposium/Workshop Santarém, Pará, Brazil 18-22.4.1993. Intern. Inst. Trop. Forestry (IITF), USDA-Forest Service, Río Piedras, Puerto Rico, USA.  40-43. 
Thielen-Klinge, A., A. Wanisch, M. Denich, M.M.L.S. Santos, and P.L.G. Vlek.  1995.  Natural Abundance of 15N in Fallow Vegetation of Northeast Pará State, Brazil - Preliminary Results.  In: J.A. Parrotta, and M. Kanashiro (eds.): Management and Rehabilitation of Degraded Lands and Secondary Forests in Amazonia. Proc. Intern. Symposium/Workshop Santarém, Pará, Brazil 18-22.4.1993. Intern. Inst. Trop. Forestry (IITF), USDA-Forest Service, Río Piedras, Puerto Rico, USA.  108-1. 
Vlek, P.L.G.  1995.  The soil and its artisans in sub-Saharan African agriculture.  Geoderma, 67 : 165-170 .
Vlek, P.L.G., M.Y. Diakite, and H. Mueller.  1995.  "The Role of Azolla in Curbing Ammonia Volatilization from Flooded Rice Systems".  Fertilizer Research, 42 : 165-174 .
Wiesenmüller, J., M. Denich, and P.L.G. Vlek.  1995.  "Vegetative Fallow Regeneration in the Eastern Amazon Region, Brazil".  In: J.A. Parrotta, and M. Kanashiro (eds.): Management and Rehabilitation of Degraded Lands and Secondary Forests in Amazonia. Proc. Intern. Symposium/Workshop Santarém, Pará, Brazil 18-22.4.1993. Intern. Inst. Trop. Forestry (IITF), USDA-Forest Service, Río Piedras, Puerto Rico, USA.  111-114. 

1994

Lüttger, A.B., G.G.B. Manske, R.K. Behl, and P.L.G. Vlek.  1994.  Felduntersuchungen in Nordindien zur Charakterisierung von.  Ökophysiologie des Wurzelraumes, Nr. 5 : 104-107 .
Manske, G.G.B., and P.L.G. Vlek.  1994.  The Prospects of Developing Nutrient Efficient Varieties (NEV) for Wheat Based on Symbiosis with VA Mycorrhizal Fungi.  In: R.K. Behl (eds.): Crop Tolerance to Abiotic Stresses. Proc. Nat. Conf. Plant Res. Develop., Feb. 26-28, 1990. CCS Haryana Agric. Univ. Press, Hisar..  171-188. 
Vlek, P.L.G., and K. Vielhauer.  1994.  Nutrient Management Strategies in Stressed Environments".  In: S.M. Virmani, J.C. Katyal, H. Eswaran and I.P. Abrol (eds.): Stressed Ecosystems and Sustainable Agriculture. S.M. Virmani. Oxford & IBH Publishing Co., New Delhi, India.  203-229. 

1993

Lüttger, A.B., G.G.B. Manske, R.K. Behl and P.L.G. Vlek.  1993.  Nährstoff-aneignung von Weizensorten in Abhängigkeit von VA-Mykorrhiza und Gesamt¬wurzellänge: Felduntersuchungen in Nordindien. (Nutrient uptake by wheat varieties as a function of VA mycorrhiza and root length: Field studies in north India).  Ökophysiologie des Wurzelraumes Nr. 4. Zentrum für Agrarlandschafts- und Landnutzungsforschung (ZALF), Müncheberg, Deutschland.  49-52. 
Vlek, P.L.G.  1993.  "Strategies for Sustaining Agriculture in sub-Saharan Africa: The Fertilizer Technology Issue".  In: Ragland, J. and R. Lal (eds.): Technologies for Sustainable Agriculture in the Tropics. ASA Special Publication No 56. , Madison, WI, USA.  265-278. 

1992

Fresco, L.O., and P.L.G. Vlek.  1992.  "Temperate" and "Tropical" Agronomy: A Case for Symbiosis.  Proc. 2nd European Society for Agronomy Congress. Warwick Univ. U.K., August 1992.
Hong, C.W., J.C. Katyal and P.L.G. Vlek.  1992.  "Losses and Utilization of Nitrogen by Sorghum as Affected by the Depth of a Swelling Clay Soil".  J. Agronomy and Crop Science, 168 : 263-271 .
Vlek, P.L.G. and H. Koch.  1992.  "The Soil Resource Base and Food Production in the Developing World: Special Focus on Africa".  Göttinger Beiträge zur Land- und Forstwirtschaft in den Tropen und Subtropen, 71 : 139-160 .
Vlek, P.L.G., W. Fugger and U. Biker.  1992.  The fate of fertilizer N under Azolla in wetland rice.  Proc. 2nd ESA Congress. Warwick Univ., UK., August 1992.

1991

Christianson, C.B., and P.L.G. Vlek.  1991.  Alleviating soil fertility constraints to food production in West Africa: Efficiency of nitrogen fertilizers applied to food crops.  Fertilizer Research, 29 : 21-33 .
Manske, G.G.B. and P.L.G. Vlek.  1991.  Eine Strategie für die Entwicklung von nährstoffeffizienten Pflanzensorten unter Einbezug der VA-Mykorrhiza. (A strategy for developing nutrient efficient varieties (NEV's) with special reference to VA mycorrhiza).  Ökophysiologie des Wurzelraumes , Forschungszentrum für Bodenfruchtbarkeit Müncheberg, Deutschland, Nr. 2 : 84-89 .
Stumpe, J.M., and P.L.G. Vlek.  1991.  Acidification induced by different nitrogen sources in columns of selected tropical soils.  Soil Sci. Soc. Am. J., 55: Jan/Feb .

1990

Buresh, R.J., P.L.G. Vlek, and K. Harmsen.  1990.  "Fate of fertilizer nitrogen applied to wheat under simulated Mediterranean environmental conditions".  Fertilizer Research, 23 : 25-36 .
Christianson, C.B., A. Bationo, J. Henao, and P.L.G. Vlek.  1990.  Fate and efficiency of N fertilizers applied to pearl millet in Niger.  Plant and Soil, 125 : 221-231 .
Mughogbo, S.K., C.B. Christianson, J.M. Stumpe, and P.L.G. Vlek.  1990.  "Nitrogen Efficiency at three sites in Nigeria as affected by N Source and Management".  Trop. Agric (Trinidad), Vol.67 : 127-132 April .
Vlek, P.L.G.  1990.  "The role of fertilizers in sustaining agriculture in sub-Saharan Africa".  Fertilizer Research, 26 : 327-339 .

1989

Stumpe, J.M., P.L.G. Vlek, S.K. Mughogho, and F.Ganry.  1989.  Microplot Size Requirements for Measuring Balances of Fertilizer 15N Applied to Maize.  Soil Sci. Soc. Am. J., 53 : 797-800 .
Vlek, P.L.G., and A. Uzo Mokwunye.  1989.  Soil Fertility Problems in the Semiarid Tropics of Africa.  In: C.B. Christianson (eds.): Soil Technology and Fertilizer Management in Semi-Arid Tropical India. IFDC Special Publication - 11 Muscle Shoals, Al. 35662, USA. 

1988

Abdelmonem, M.A.S., K. Harmsen, W.L. Lindsay and P.L.G. Vlek.  1988.  Fate of nitrogen-tagged urea applied to wheat in the arid Mediterranean region.  In: Matar, A., P.N. Soltanpour and A. Chouinard (eds.): Soil test calibration in West Asia and North Africa. Proceedings of the second regional workshop, Ankara, Turkey, 1-6 September 1987. ICARDA-120 En. ICARDA, Aleppo, Syria.  103-110. 
Cori, C.E. de, L.S. Holt, and P.L.G. Vlek.  1988.  Destino del Nitrógeno Ureico Aplicado a un Tropaquept Arcilloso, bajo Condiciones Similadas de Arroz en Siembra Directa ("Fate of urea nitrogen applied to a clayey Tropaquept, under simulated conditions in direct seeded rice".  Turrialba, 38 (4) : 294-299 .
Katyal, J.C., Bijay Singh, and P.L.G. Vlek.  1988.  Effect of Granule Size and the Placement Geometry on the Efficiency of Urea Supergranules for Wetland Rice Grown on a Permeable Soil.  Fert. Res., 15 : 193-201 .
Katyal, J.C., M.F. Carter, and P.L.G. Vlek.  1988.  Nitrification Activity in Submerged Soils and Its Relation to Denitrification Loss.  Biology and Fertility of Soils, 7 : 16-22 .

1987

Katyal, J.C., Bijay Singh, P.L.G. Vlek, and R.J. Buresh.  1987.  Efficient N Use as Affected by Urea Application and Irrigation Sequence.  Soil Sci. Soc. Am. J., 51 : 366-370 .
Katyal, J.C., C.W. Hong, and P.L.G. Vlek.  1987.  Fertilizer Management in Vertisols.  Proceedings Seminar on Management of Vertisols under Semi-Arid Conditions. IBSRAM Nairobi, Kenya. 
Katyal, J.C., D.K. Friesen, and P.L.G. Vlek.  1987.  Deficiencies of Micronutrients and Sulfur in Wheat.  Proceedings Conference on Wheat Production Constraints in Tropical Environments. CIMMYT, Chiang Mai, Thailand. 

1986

Ashby, J.A., and P.L.G. Vlek.  1986.  Farming Systems Research of the International Fertilizer Development Center. IARC Workshop on Farming Systems Research.  ICRISAT, Feb. : 17-21 .
Carter M.F., P.L.G. Vlek, and J.T. Touchton.  1986.  Agronomic Evaluation of New Ureaforms for Flooded Rice.  Soil Sci. Soc. Am. J., 50 : 1055-1060 .
Fillery, I.R.P., and P.L.G. Vlek.  1986.  Reappraisal of the Significance of Ammonia Volatilization as an N loss Mechanism in Flooded Rice Fields.  In: S.K. DeDatta and W.H. Patrick (eds.): Nitrogen Economy in Flooded Rice Soils. Martinus Nijhoff Publishers, Dordrecht, The Netherlands.  79-99. 
Mughogho, S.K., A. Bationo, B. Christianson and P.L.G. Vlek.  1986.  Management of Nitrogen Fertilizers for Tropical African Soils.  In: Mokwunye, A.U., and P.L.G. Vlek (eds.): "Management of Nitrogen and Phosphorus Fertilizers in Sub-Saharan Africa". Martinus Nijhoff Publishers. The Hague, The Netherlands.  117-172. 
Sillanpaa, M., and P.L.G. Vlek.  1986.  Micronutrients and the Agro-Ecology of Tropical and Mediterranean Regions.  Fertilizer Research, 7 : 131-150 .
Singh, B., J.C. Katyal, P.K. Malhotra, and P.L.G. Vlek.  1986.  Path Coefficient Analysis of N Nutrition on Yield and Yield Components for Rice in a Highly Percolating Soil.  Commun. in Soil Sci. Plant Anal, 17 : 853-867 .
Vlek, P.L.G., and B.H. Byrnes.  1986.  The Efficacy and Loss of Fertilizer N in Lowland Rice.  In: S.K. DeDatta and W.H.Patrick, Jr. (eds.): Nitrogen Economy in Flooded Rice Soils. Martinus Nijhoff Publishers, Dordrecht, The Netherlands.  131-148. 

1985

Craswell, E.T., S.K. De Datta, C.S. Weeraratne, and P.L.G. Vlek.  1985.  Fate and Efficiency of Nitrogen Fertilizers Applied to Wetland Rice. I. The Philippines.  Fertilizer Research, 6 (1) : 49-63 .
Godwin, D.C., and P.L.G. Vlek.  1985.  Simulation of Nitrogen Dynamics in Wheat Cropping Systems.  In: W. Day (eds.): Wheat Growth and Modeling. NATO Advanced Research Series.  311-332. 
Harmsen, K. and P.L.G. Vlek.  1985.  "The Chemistry of Micronutrients in Soil".  Fertilizer Research, 7 : 1-42 .
Katyal, J.C., and P.L.G. Vlek.  1985.  "Micronutrient Problems in Tropical Asia".  Fertilizer Research, 7 : 69-94 .
Katyal, J.C., Bijay Singh, P.L.G. Vlek, and E.T. Craswell.  1985.  Fate and Efficiency of Nitrogen Fertilizers Applied to Wetland Rice. II. Punjab, India.  Fertilizer Research, 6 (3) : 279-290 .
Leon, L.A., A.S. Lopez, and P.L.G. Vlek.  1985.  "Micronutrient Problems in Tropical Latin America".  Fertilizer Research, 7 : 95-130 .
Mokwunye, A.U., and P.L.G. Vlek.  1985.  Feeding the African People or Feeding Crops that Feed the People:Food for Thought.  Agribusiness Worldwide, 8 : 6-8 .
Van der Heide, J., A.C.B.M. van der Kruijs, B.T. Kang, and P.L.G. Vlek.  1985.  Nitrogen Management in Multiple Cropping Systems.  In: B.T. Kang and J. van der Heide (eds.): Nitrogen Management in Farming Systems in Humid and Subhumid Tropics. Symposium Proceedings, Ibadan, Nigeria.  291-306. 
Vlek, P.L.G (Editor).  1985.  Micronutrients in Tropical Foodcrop Production.  Martinus Nijhoff/Dr. W. Junk Publishers. The Hague, the Netherlands.

1984

Bouwmeester, R.J.B., P.L.G. Vlek, and J.M. Stumpe.  1984.  Effect of Environmental Factors on NH3 Volatilization from a Urea-Fertilized Soil.  Soil Sci. Soc. Am. J., 49 (2) : 376-381 .
Buresh, R.J., P.L.G. Vlek, and J.M. Stumpe.  1984.  Labelled Nitrogen Fertilizer Research with urea in the Semi Tropics: I. Greenhouse Studies.  Plant and Soil, 80 : 3-19 .
Moraghan, J.T., T.J. Rego, R.J. Buresh, P.L.G. Vlek, J.R. Burford, S. Singh and K.L. Sahrawat.  1984.  Labelled Nitrogen Fertilizer Research with Urea in the Semi-Arid Tropics:II.Field Studies on a Vertisol.  Plant and Soil, 80 : 21-33 .
Stumpe, J.M., P.L.G. Vlek, and W.L. Lindsay.  1984.  Ammonia Volatilization from Urea and Urea Phosphates in Calcareous Soils.  Soil Sci. Soc. Am. J., 48 (4) : 921-927 .
Vlek, P.L.G., and I.R.P. Fillery.  1984.  Improving Nitrogen Efficiency in Wetland Rice Soils.  The Fertilizer Society Proceedings, No. 230 .

1983

Craswell, E.T. and P.L.G. Vlek.  1983.  Fate of Fertilizer Nitrogen in Flooded Systems.  In: J. Simpson and J.R.Freney (eds.): Gaseous Losses of Nitrogen from Plant Soil Systems. Martinus Nijhoff Publishers. The Hague, The Netherlands. 
Godwin, D.C., C.A. Jones, J.T. Ritchie, P.L.G. Vlek, and L.J. Youngdahl.  1983.  The Water and Nitrogen Components of the CERES Models.  Minimum Data Sets for Agrotechnology Transfer. IBSNAT/ICRISAT Symposium, Hyderabad, India, March 1983. 
Osiname, O., H. van Gijn, and P.L.G. Vlek.  1983.  The Effect of Nitrification Inhibitors on the Fate and Efficiency of Nitrogenous Fertilizers Under Simulated Humid Tropical Conditions.  Tropical Agriculture, 60 : 211-217 .
Vlek, P.L.G., and M.F. Carter.  1983.  The Effect of Soil Environment and Fertilizer Modification on the Kinetics of Hydrolysis of Applied Urea.  Soil Science, 136 : 56-63 .

1982

Craswell, E.T., and P.L.G. Vlek.  1982.  Nitrogen Management for Submerged Rice Soils.  Vertisols and Rice Soils of the Tropics, Symposia Papers II. 12th International Congress of Soil Science, New Delhi, India.  
El-Zahaby, E.M., S.H. Chien, N.K. Savant, P.L.G. Vlek, and A.U. Mokwunye.  1982.  Effect of Pyrophosphate on Phosphate Sorption and Ammonia Volatilization by Calcareous Soils Treated with Ammonium Phosphates.  Soil Sci. Soc. Am. J., 46 : 733-740 .
Fillery, I.R.P., and P.L.G. Vlek.  1982.  The Significance of Denitrification of Applied Nitrogen in Fallow and Cropped Rice Soils Under Different Flooding Regimes.  Plant and Soil, 65 : 153-169 .
Moeller, M.B., and P.L.G. Vlek.  1982.  The Chemical Dynamics of Ammonia Volatilization from Aqueous Solution.  Atmospheric Environment, 16 : 709-7l8 .
Vlek, P.L.G., and E.T. Craswell.  1982.  Ammonia Volatilization from Flooded Soils.  Fertilizer Research, 2 : 227-245 .
Youngdahl, L.J., R. Pacheco, J.J. Street, and P.L.G. Vlek.  1982.  The Kinetics of Ammonium and Nitrate Uptake by Young Rice Plants.  Plant and Soil, 69 : 225-232 .

1981

Bouwmeester, R.J.B., and P.L.G. Vlek.  1981.  Wind-Tunnel Simulation and Assessment of Ammonia Volatilization from Ponded Water.  Agronomy Journal, 73 : 546-552 .
Bouwmeester, R.J.B., and P.L.G. Vlek.  1981.  Rate Control of Ammonia Volatilization from Rice Paddies.  Atmospheric Environment, 15 : 131-140 .
Vlek, P.L.G., I.R.P. Fillery, and J.R. Burford.  1981.  Accession, Transformation and Loss of Nitrogen in Soils of the Arid Region.  Plant and Soil, 58 : 133-175 .

1980

Craswell, E.T., and P.L.G. Vlek.  1980.  Research to Reduce Losses of Fertilizer Nitrogen from Wetland Rice Soils.  Fertilizers in India in the Eighties, FAI Annual Seminar, December 4-6, 1980, New Delhi, India.  
Tejeda, H.R., C.W. Hong, and P.L.G. Vlek.  1980.  Comparison of Modified Urea Fertilizers and Estimation of their availability Coefficient Using Quadratic Models.  Soil Sci. Soc. Am. J., 44 : 1256-1262 .
Vlek, P.L.G., B.H. Byrnes, and E.T. Craswell.  1980.  Effect of Urea Placement on Leaching Losses of Nitrogen from Flooded Rice Soils.  Plant and Soil, 54 : 441-449 .
Vlek, P.L.G., J.M. Stumpe, and B.H. Byrnes.  1980.  Urease Activity and Inhibition in Flooded Soil Systems.  Fertilizer Research, 1 : 191-202 .

1979

Byrnes, B.H., P.L.G. Vlek, and E.T. Craswell.  1979.  The Promise and Problem of Super Granules for Rice Fertilization.  In: S. Ahmed et al. (eds.): Adoptive Production Systems.  
Vlek, P.L.G., C.W. Hong, and L.J. Youngdahl.  1979.  An Analysis of N Nutrition on Yield and Yield Components for the Improvement of Rice Fertilization in Korea.  Agronomy Journal, 71 : 829-833 .

1978

Craswell, E.T., and P.L.G. Vlek.  1978.  Fate of Fertilizer Nitrogen Applied to Wetland Rice.  Nitrogen and Rice, Symposium proceedings. International Rice Research Institute, Manila, Philippines.  l75-l93. 
Vlek, P.L.G., and E.T. Craswell.  1978.  Effect of Nitrogen Source and Management on Ammonia Volatilization Losses from Flooded Rice Soil Systems.  Soil Sci. Soc. Am. Proc., 43 : 352-358 .
Vlek, P.L.G., and J.M. Stumpe.  1978.  Effects of Solution Chemistry and Environmental Conditions on Ammonia Volatilization Losses from Aqueous Systems.  Soil Sci. Soc. Am. J., 42 : 4l6-421 .
Vlek, P.L.G., and W.L. Lindsay.  1978.  Potential Use of Finely Disintegrated Iron Pyrite in Sodic and Iron-Deficient Soils.  Journal of Environmental Quality, 7 : 111-114 .

1977

Lindsay, W.L., and P.L.G. Vlek.  1977.  Phosphate Minerals.  In: J.B. Dixon and B.S. Weed (eds.): Minerals in Soil Environments. Soil Sci. Soc. Am., Inc., Madison, Wisconsin.  639-670. 
Vlek, P.L.G., and W.L. Lindsay.  1977.  Thermodynamic Stability and Solubility of Molybdenum Minerals in Soils.  Soil Sci. Soc. Am. J., 41 : 42-46 .
Vlek, P.L.G., and W.L. Lindsay.  1977.  Molybdenum Contamination in Colorado Pasture Soils.  In: W.K. Chappell and K. Kellogg Petersen (eds.): Molybdenum in the Environment, Vol. II. Marcel Dekker, Inc., New York.  6l9-650. 

1974

Vlek, P.L.G., Th.J.M. Blom, J. Beek, and W.L. Lindsay.  1974.  Determination of the Solubility Product of Various Iron Hydroxides and Jarosite by the Chelation Method.  Soil Science Society of America Proceedings, 38 (3) : 429-432 .

1971

Vlek, P.L.G.  1971.  Some Morphological, Physical and Chemical Aspects of Acid Sulphate Soils in Thailand.  Soil Survey Report No. 84, Department of Land Development, Bangkok, Thailand, .

Additionals, Curriculum Vitae
and Downloads

Paul L. G. Vlek

Director Emeritus

Phone:
+49-228-73-1816

Department:
ZEF C: Department of Ecology and Natural Resources Management

E-Mail:
p.vlek(at)uni-bonn.de