Oba, G., N.C. Stenseth, and W.J. Lusigi. 2000. New perspectives on sustainable grazing management in arid zones of sub-Saharan Africa. BioScience 50:35-51.

Oberhauser, K., and A. T. Peterson. 2003. Modeling current and future potential wintering distributions of eastern North American monarch butterflies. PNAS 100:14063-14068.

Obrist, L.B., A. Dutton, R. Albajes, and F. Bigler 2006. Exposure of arthropod predators to Cry1Ab toxin in Bt maize fields. Ecol. Entomol. 31:143-154.

Oden, N.H, A. Maarouf, I.K. Barker, M. Bigras-Poulin, L.R. Lindsay, M.G. Morshed et al. 2006. Climatic change and the potential for range expansion of the Lyme disease vector Ixodes scapularis in Canada. Int. J. Parasitol. 36(1):63-70.

OECD. 1986. Recombinant DNA safety considerations for industrial, agricultural and environmental applications of organisms derived by recombinant DNA techniques ('The Blue Book'). OECD, Paris.

OECD. 1993. Safety considerations for biotechnology: Scale-up of crop plants. OCED, Paris.

OECD. 1997. Impacts of fruit and vegetable production on the environmental and policy responses: European Union Community instruments relating to the environmental aspects of the fresh fruit and vegetable sector. OECD, Paris.

OECD. 2005. Review of agricultural policies — Brazil. OECD, Paris.

OECD. 2006a. Agricultural market impacts of future growth in the production of biofuels. OECD, Paris. Available at http://www.oecd .org/dataoecd/58/62/36074135.pdf.

OECD. 2006b. Promoting pro-poor growth, harmonising ex ante poverty impact assessment. OECD, Paris.

Ogunwale, A.B., and E.A. Laogun. 1997. Extension agents' avenues for information dissemination and other perception of farmers sources of information in Oyo State Agric. Dev. Program. p. 141-118. In T.A. Olowu (ed) Towards the survival of agricultural extension system in Nigeria. Proc. Third Ann. Nat. Conf. Agric. Extension Soc. Nigeria (AESON). Ilorin.

Ohm, H.W., F.L. Patterson, S.E. Ratcliffe, S.E. Cambron, and C.E. Williams 2004. Registration of Hessian fly resitant wheat germplasm line P921696. Crop Sci 44:2272-2273.

Ojima, D.S., W.J. Parton, D.S. Schimel, J.M.O. Scurlock, and T.G.F. Kittel. 1993. Modeling the effects of climate and CO2 changes on grassland storage of soil C. Water, Air, Soil Pollution 70:643-657.

Okafor, J.C. 1980. Edible indigenous woody plants in the rural economy of the Nigerian forest zone. Forest Ecol. Manage. 3:45-55.

Okali, C., J. Sumberg, and J. Farrington. 1994. Farmer participatory research. ODI, London.

Okoth, J.R., G.S. Khisa, and T. Julianus, 2003.

Towards self financed farmer field schools. LEISAMag. 19(1):28-29.

Olivier de Sardan, J.P. 1995. Anthropologie et développement. Essai en socio-anthropologie du changement social, p. 221. Hommes et sociétés. Karthala, Paris.

Olowu, T.A., and C.O. Igodan. 1989. Farmers' media use pattern in six villages of Kwara State. Rural Dev. Nigeria 3(2):98-102.

Olsen, J., L. Kristensen, J. Weiner, and H.W. Griepentrog. 2005. Increased density and spatial uniformity increase weed suppression by spring wheat. Weed Res. 45:316-321.

Omernik, J.M. 1977. Nonpoint source-stream nutrient level relationships - A nationwide study. EPA Res. Series EPA-600/3-P77-105. US EPA, Corvallis Environmental Res. Laboratory.

Ong, C.K., and P. Huxley. 1996. Tree-crop interactions: A physiological approach. CABI Wallingford.

Ong, C.K., C.R. Black, F.M. Marshall, and J.E. Corlett. 1996. Principles of resource capture and utilization of light and water, p. 73-158. In C.K. Ong and P. Huxley (ed) Tree-crop interactions: A physiological approach. CABI, Wallingford.

Opara, L.U., and F. Mazaud. 2001. Food traceability from food to plate. Outlook Agric. 30:239-247.

Orr, A. 2003. IPM for resource-poor African farmers: Is the emperor naked? World Dev. 31 (5):831-846.

Ørskov, E.R., and E.F. Viglizzo. 1994. The role of animals in spreading farmer's risks: A new paradigm for animal science. Outlook Agric. 23:81-89.

Ostrom, E. 1992. The rudiments of a theory of the origins, survival, and performance of common-property institutions. In D.W. Bromley (ed) Making the commons work: Theory, practice and policy. ICS Press, San Francisco.

Ostrom, E. 1994. Institutional analysis, design principles and threats to sustainable community governance and management of commons. p. 34-50. In R.S. Pomeroy (ed) Community management and common property of coastal fisheries in Asia and the Pacific: Concepts, methods and experiences. Workshop Reprint Ser., R94-11. ICLARM, Manila.

Ostrom, E. 2005. Understanding institutional diversity. Princeton Univ. Press, Princeton NJ.

Otsuka, K., and T. Yamano. 2005. Green revolution and regional inequality: Implications of Asian experience for Africa, p. 239-252. In The African food crisis: Lessons from the Asian green revolution. CABI, Wallingford.

Otsuki, T., J.S. Wilson, and M. Sewadeh. 2001. Saving two in a billion: Quantifying the trade effect of European food safety standards on African exports. Food Policy 29:131-146.

Ottman, M.J., B.A. Kimball, P.J. Pinter Jr, G.W. Wall, R.L. Vanderlip, S.W. Leavitt et al. 2001. Elevated CO2 on sorghum growth and

yield at high and low soil water content. New Phytologist 150: 261-273.

Oweis, T., and A. Hachum. 2004. Water harvesting and supplemental irrigation for improved water productivity of dry farming systems in West Asia and North Africa. New directions for a diverse planet. Proc. 4th Int. Crop Sci. Congress. Brisbane, Australia. 26 Sept -1 Oct 2004.

Owen, M.D.K., and I.A. Zelaya. 2005. Herbicide-resistant crops and weed resistance to herbicides. Pest Manage. Sci. 61:301-311.

Padilla, M., and L. Malassis. 1992. Politiques agricoles et politiques alimentaire: Efficacite et equite. Econ. et Societes 21(6):175-192.

Pagiola, S., J. Bishop, and N. Landell-Mills. 2002. Selling forest environmental services: Market-based mechanisms for conservation and development. Earthscan, London.

Palm, C.A., M. van Noordwijk, P.L. Woomer, J.C. Alegre, L. Arévalo, C.E. Castilla et al. 2005a. Carbon losses and sequestration after land use change in the humid tropics, p. 41-63. In C.A. Palm, S.A. Vosti, P.A. Sanchez and P.J. Ericksen (ed) Columbia Univ. Press, NY.

Palm, C.A., S.A. Vosti, P.A.. Sanchez, and P. Ericksen. 2005 b. Slash-and-burn agriculture: The search for alternatives. Columbia Univ. Press, NY.

Pandey, S., and S. Rajatasereekul. 1999. Economics of plant breeding: The value of shorter breeding cycles for rice in Northeast Thailand. Field Crops Res. 64:187-197.

Panigrahy, B.K. 2003. Watershed evaluation: Problems and perspectives. p. 736-739. In B. Venkateswara Rao (ed) Proc. Int. Conf. Hydrology and Watershed Management Vol. 1. Hyderabad, India.18-20 Dec 2002. BS Publ., Hyderabad, India.

Panik, F. 1998. The use of biodiversity and implications for industrial production. p. 59-73. In D.E. Leihner and T.A. Mitschein (ed) A third millennium for humanity? The search for paths of sustainable development. Peter Lang, Frankfurt am Main, Germany.

Parella, M.P., L. Stengarf Hansen, and J. van Lenteren. 1999. Glasshouse environments, p. 819-839. In T.S. Bellows and T.W. Fisher (ed) Handbook of biological control. Principles and applications of biological control. Academic Press, San Diego, London.

Parker, C., and J. Fryer. 1975. Weed control problems causing major reduction in world supplies. FAO Plant Prot. Bull. 23:83-95.

Passioura, J.B. 1986. Resistance to drought and salinity: Avenues for improvement. Aust. J. Plant Physiol. 13:191-201.

Patterson R.E., P.S., Haines, and B.M. Popkin. 1994. Diet Quality Index: capturing a multidimensional behavior. J. Am. Dietary Assoc. 94:57-64.

Paustian, K., C.V. Cole, D. Sauerbeck, and N. Sampson. 1998. CO2 mitigation by agriculture: An overview. Clim. Change 40:135-162.