Graduate classes

ENVS 230 Agroecology & Sustainable Agriculture

ENVS 291 – Advanced Reading in Environmental Studies – Participatory
research

Upper division undergraduate

ENVS 100 Ecology and Society

ENVS 130A Intro to Agroecology

ENVS 130L Agroecology laboratory

ENVS 133B Agroecology Practicum

ENVS 166/196 Agroecosystem analysis and watershed management

I anticipate accepting one or two students over the next 3 years (2008-2010.

My current research examines the ecological and social dimensions of agricultural sustainability in a number of contrasting systems; a) intensive vegetable/strawberry production systems in the Monterey Bay region; b) irrigated rice production in Senegal; c) Subsistence maize production in Southern Malawi; d)Enset based agriculture in SW Ethiopian highlands; and e) grazing, crop production and grassland conservation in Inner Mongolia (project in development stage). All studies involve working closely on-farm with groups of farmers and other interested parties. In the California-based projects our approaches include:

Watershed-level assessment of surface water quality dynamics and in-stream processes in a context of changing water policies;

Studies of fertility management and nutrient cycling (emphasis on organic systems), and the use of nutrient budgets and simulation models as management tools and predictors of nutrient losses;

Examining the ability of perennial vegetation (hedgerows, fragments of natural habitats) to enhance biocontrol and provide other ecosystem services;

Developing alternative strategies for pest control, with an emphasis on soil borne fungal diseases and the use of an organic matter driven anaerobic soil disinfestation technique;

Examining barriers and opportunities to increased adoption of ecological practices, including alternative marketing strategies, consumer education, and roles of different players in the conventional market system.

In Malawi we are concluding an interdisciplinary project examining the impacts of organic matter technologies (legume intercrops) on livelihoods of small farmers and sustainability of maize production systems over multiple time-scales.

In Senegal we are testing effects of organic matter management, plant spacing, and irrigation strategies on rice production and small holder livelihoods. In Ethiopia we are studying extremely diverse and unique production systems that have evolved to be sustainable over many thousands of years. The region is now faced with increased population pressure and other challenges requiring new adaptations to sustain livelihoods, crop biodiversity and environmental health.

1997- present Professor, Environmental Studies, & Director of Center for Agroecology& Sustainable Food Systems, UC Santa Cruz
1992-1997 Associate Professor, Department of Vegetable Crops, UC Davis
1985-1992 Assistant Professor, Department of Vegetable Crops UC Davis
1982-84 Postdoctoral Research Associate, University of Sydney, Australia
1982 Ph.D. University of Cambridge, U.K. Botany.
Thesis: Physiological basis of salinity tolerance in Aster tripolium.
1977 B.A. University of Cambridge, U.K.
Natural Sciences - First Class Honors: specialization – Botany

Selected Publications
Shennan, C. (In Press) Biotic Interactions, Ecological Knowledge and Agriculture. Philosophical Transactions of the Royal Society, UK.

Ruehl CR, Fisher AT, Huertos ML, et al. 2007. Nitrate dynamics within the Pajaro River, a nutrient-rich, losing stream. J. N. Am Benthological Society 26: 191-206 Pasakdee, S.J., G. Bañuelos, C. Shennan3 and W. Cheng. (In Press). Organic N fertilizers and irrigation influence organic Broccoli production in two regions of California. Journal of Vegetable Science

Ruehl C., Fisher, A.T., Hatch, C., Los Huertos, M., Stemler, G. and C. Shennan. (2006). Differential gauging and tracer tests resolve seepage fluxes in a strongly-losing stream. J. Hydrology 30 : 235-248

Los Huertos, M. and C. Shennan. (In press). Regulations and Grower Responses to Reduce Nitrogen Losses in California. Pedosphere.

Nieto, D.J., C. Shennan, W.H. Settle, R. O'Malley, S. Bros, and J. Y. Honda. 2006. How Natural Enemies and Aphid Population Dynamics Affect Organic Broccoli Harvest. Environmental Entomology 35: 94-101

Bull, C. T., Muramoto, J., Koike, S. T., Leap, J., Shennan, C., and Goldman, P. 2005. Strawberry cultivars and mycorrhizal inoculants evaluated in California organic production fields. Online. Crop Management doi:10.1094/CM-2005-0527-02-RS.

Shennan, C., T. Pisani Gareau, J.R. Sirrine. 2004. Agroecological Approaches to Pest Management in the U.S. In “The Pesticide Detox: Solutions for Safe Agriculture”. Ed. J. Pretty. Earthscan Publications Ltd. London.

Los Huertos, M. and C. Shennan. 2002. The Soil Resource of Elkhorn Slough. In: Changes in a California Estuary: A Profile of Elkhorn Slough, J.Caffrey, M. Brown, and B. Tyler, eds

Shennan, C. and C. A. Bode. Integrating Wetland Habitat with Agriculture. 2002. In "The Farm as a Natural Habitat". Eds. Laura L. Jackson and Dana Jackson. Island Press.

Los Huertos, M., L.E. Gentry and C. Shennan. 2001. Land Use and Stream Nitrogen Concentrations in Agricultural Watersheds Along the Central Coast of California. In: Optimizing Nitrogen Management in Food and Energy Production and Environmental Protection. Proc. 2nd International Nitrogen Conference on Science and Policy. Scientific World 1

Shennan, C., C.L. Cecchettini, G.B. Goldman, F.G. Zalom, 2001. Profiles of California farmers by degree of IPM use as indicated by self -descriptions in a phone survey. Agriculture, Ecosystems and Environment 84:267-275

Mitchell, J.P*., C. Shennan., M.J. Singer, D. Peter, R.O. Miller, T. Prichard, S.R. Grattan, J.D. Rhoades, D.M. May and D.S. Munk. 2000. Impacts of gypsum and winter cover crops on soil physical properties and crop productivity when irrigated with saline water. Agricultural Water Management 45:55-71

Clark, M.S., W.R. Horwarth, C. Shennan, K.M. Scow, W.T. Lanini and H. Ferris. 1999. Nitrogen, weeds and water as yield-limiting factors in conventional, low-input and organic tomato systems. Agriculture, Ecosystems and Environment 73:257-70

Cavero, J., R.E. Plant, C. Shennan, D.B. Friedman, J.R. Williams, J.R. Kiniry, and V. W. Benson. 1999. Modeling Nitrogen Cycling in Tomato-Safflower and Tomato-Wheat Rotations. Agricultural Systems 60: 123-135

Mitchell, J.P*. D.W. Peters and C. Shennan. 1999. Changes in soil water storage in winter fallowed and cover cropped soils. Journal of Sustainable Agriculture. 15:19-31

Shennan, C., and W. M. Jarrell. 1999. Assessing sustainability of a managed multi-use ecosystem: a case study of wetland and cropland management in the Tulelake National Wildlife Refuge, California. In Suteera Nagavajara (Ed.) "Agriculture and Ecological Resilience: Striking a balance in the Pacific Rim" First Asia-Pacific Conference on Sustainable Agriculture”, Beijing, October 1998. AAAS.

Clark, M.S., W.R. Horwarth, C. Shennan, K.M. Scow. 1998. Changes in soil chemical properties resulting from organic and low-input farming practices. Agronomy Journal. 90:662-671

Cavero, J., R.E. Plant and C. Shennan. 1998. Application of the Epic model to nitrogen cycling in irrigated processing tomatoes under different management systems. Agricultural Systems: 56, No. 4, pp. 391-41

Cavero, J., R.E. Plant, C. Shennan, D.B. Friedman. 1997. Nitrogen dynamics in processing tomatoes under conventional, low input and organic management systems. Nitrogen Cycling in Agroecosystems 47: 271-282.

Letourneau, D.K., L.E. Drinkwater and C. Shennan. 1996. Effects of soil management on crop nitrogen and insect damage in organic vs conventional tomato fields. Agriculture, Ecosystems and Environment.

Roberson, E.B., S. Sarig, C. Shennan and M.K. Firestone. 1995. Nutritional management of microbial polysaccharide production and aggregation in an agricultural soil. Soil Science Society of America 59:1587-1594

Drinkwater, L.E., F. Workneh, D.K. Letourneau, A.H.C. van Bruggen and C. Shennan. 1995. Fundamental differences between organic and conventional tomato agroecosystems in California. Ecological Applications. Vol. 5:1098-1112

Shennan, C., S.R. Grattan, D.M. May, C.J. Hillhouse, D.P. Schachtman, M. Wander, B. Roberts, R.G. Burau, C. McNeish, L. Zelinski and S. Tafoya. 1995, Feasibility of cyclic reuse of saline drainage in a tomato-cotton rotation. Journal of Environmental Quality . Vol. 24:476-486.

Snapp, S.S. and C. Shennan. 1994. Salinity effects on root growth and senescence in tomato and the consequences for severity of Phytophthora root rot infection. Journal of the American Society for Horticultural Science. Vol. 119(3):458-463

Workneh, F., A.H.C. van Bruggen, L.E. Drinkwater and C. Shennan. 1993. Variables associated with corky root and Phytophthora root rot of tomatoes in organic and conventional farms. Phytopathology . Vol. 83(5):581-589.

Stivers, L.J., C. Shennan, L.E. Jackson, K. Groody, C.J. Griffin and P.R. Miller. 1993. Winter cover cropping in vegetable production systems in California. In: Proc. 2nd Annual International Symposium on Agroecology and Conservation in Temperate and Tropical Regions. University of Padova, Italy, Vol. I, Soil Biota and Nutrient Cycling in Farming Systems. pp. 227-240.

Snapp, S.S. and C. Shennan. 1992. Effects of salinity on root growth and death dynamics of tomato, Lycopersicon esculentum Mill. The New Phytologist . Vol. 121:71-79.

Shennan, C. 1992. Cover crops, nitrogen cycling and soil properties in semi-arid irrigated vegetable production systems. HortScience. Vol. 27(7):749-754

Snapp, S.S. and C. Shennan and A.H.C. van Bruggen. 1991. Effects of salinity on severity of infection by Phytophthora parasitica Dast,. ion concentrations and growth of tomato, Lycopersicon esculentum. The New Phytologist . Vol. 119:275-284.

Shennan, C., L.E. Drinkwater, A.H.C. van Bruggen, D.K. Letourneau and F. Workneh. 1991. Comparative study of organic and conventional tomato production systems: An approach to on-farm systems studies. In: Sustainable Agriculture Research and Education in the Field, J.P. Madden (ed.), National Academy Press.

Stivers, L.J. and C. Shennan. 1991. Meeting the nitrogen needs of processing tomatoes through winter cover cropping. Journal of Production Agriculture. Vol. 4(3):330-335.

Abrams, M.M., C. Shennan, R.J. Zasoski and R.G. Burau. 1990. Selenomethionine uptake by wheat seedlings. Agronomy Journal. Vol. 82:1127-1130.

Shennan, C., D.P. Schachtman and G. R. Cramer. 1990. Variation in [75]selenate uptake and partitioning among tomato cultivars and wild species. New Phytologist . Vol. 115:523-530.

Munns, R., M.L. Tonnet, C. Shennan and P.A. Gardner. 1988. Effect of high external NaCl concentration on ion transport within the shoot of Lupinus albus. II. Ions in phloem sap. Plant, Cell and Environment . Vol. 11:291-300.

Shennan, C. 1987. Salt tolerance in Aster tripolium L. III. Na and K fluxes in intact seedlings. Plant, Cell and Environment . Vol. 10:75-81.

Shennan, C., R. Hunt and E.A.C. MacRobbie. 1987. Salt tolerance in Aster tripolium L. II. Ionic regulation. Plant, Cell and Environment . Vol. 10:67-74.

Shennan, C., R. Hunt and E.A.C. MacRobbie. 1987. Salt tolerance in Aster tripolium L. I. The effect of salinity on growth. Plant, Cell and Environment . Vol. 10:59-65.

Pitman, M.G. and C. Shennan. 1984. Plant growth and ion uptake. In: W.J. Cram, K. Janacek, R. Rybova and K. Siegler (ed). Membrane Transport in Plants. John Wiley and Sons, New York, NY. pp. 371-378.