Abstract
Large-scale changes in land use are occurring in many tropical regions, with significant impacts on nitrogen and phosphorus biogeochemistry. In this study we examine the relationships between land use, anthropogenic nutrient inputs, and riverine nutrient exports in a major agricultural watershed of the Pacific coast of South America, the Guayas River basin of Ecuador. We present comprehensive nutrient budgets for nitrogen (N) and phosphorous (P) for the Guayas River basin and 10 sub-watersheds. We quantify the four major anthropogenic nutrient fluxes into and out of the region: N and P fertilizer application, N fixation by leguminous crops, net import/export of N and P in agricultural products (food and feed), and atmospheric deposition. We also estimate inputs of N from biological N fixation in forests and of P from weathering sources in soils and bedrock. The sum of these sources represents net inputs of N and P to each watershed region. Overall, synthetic fertilizers are the largest input to the Guayas Basin for N (53%) and P (57%), and the largest outputs are N and P in crops. Losses of N and P in river export account for 14–38% of total N and P inputs, and there is significant accumulation of N and P, or unmeasured forms of N and P export, in most of the sub-basins. Nutrient balances are indicative of the sustainability of land use practices in a region, where a negative balance of N or P indicates nutrient depletion and subsequent loss of soil fertility, yield, and economic viability. Although the nutrient balance of the entire Guayas Basin is positive, there are negative or near zero balances in two sub-watersheds with extensive banana, coffee and permanent crops. In these basins, degradation of soil quality may be occurring due to these net nutrient losses. Our data show that nutrients are leaving the basin primarily as export crops, with riverine losses of nutrients smaller than crop exports. Nonetheless, there is a direct relationship between nutrient inputs and river outputs, suggesting that agricultural management practices in the basin may have direct impacts on N and P delivery to the highly productive Guayas estuary.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
U.S. Department of Agriculture, Agricultural Research Service 2003. USDA National Nutrient Database for Standard Reference, Release 5. Nutrient Data Laboratory Home Page, http://www.nal.usda.gov/fnic/foodcomp.
Almanaque Electrónico Ecuatoriano (AEE) 1998. Sistemas de Información Geográfica para Aplicaciones Agropecuarias en el Ordenamiento de Territorio y Manejo Integral de Cuencas. Alianza Jatun Sacha/CDC-Ecuador, Escuela Superior Politécnica del Ejercito (ESPE), y Centro Internacional de mejoramiento del maiz y trigo (CIMMYT-Ecuador).
Borbor M. 1999. A systems analysis of banana and shrimp production in Ecuador emphasizing the environmental impact on coastal ecosystems. M.S. thesis, State University of New York, College of Environmental Science and Forestry, Syracuse, NY, p. 73.
Borbor V.J. 1965. Principales pastos cultivados en las Haciendas ribereñas del rio Guayas. B.S. Thesis. Department of Agricultural Engineering. Universidad Guayaquil, Ecuador.
Boyer E.W. and Howarth R.W. (eds) 2002. The Nitrogen Cycle at Regional to Global Scales. Kluwer Academic Publishers, 518 pp.
Boyer E.W., Goodale C.L., Jaworski N.A. and Howarth R.W. 2002. Anthropogenic nitrogen sources and relationships to riverine nitrogen export in the northeastern USA. Biochemistry 57/58: 137–169.
Bruijnzeel L.A. 1996. Predicting the impacts of land cover transformation in the humid tropics: the need for integrated research. In: Gash J.H.C., Nobre C.A., Roberts J.M. and Victoria R.L. (eds.), Amazonian Deforestation and Climate, John Wiley & Sons, New York, NY, USA, pp. 15–55.
Caraco N.F. 1993. Disturbance of the phosphorus cycle: a case of indirect effects of human activity. Trends Ecol. Evolut. 7: 51–54.
Cole J.J., Peierls B.L., Caraco N.F. and Pace M.L. (1993). Nitrogen loading of rivers as a human-driven process. In: McDonnell M.J. and Pickett S.T.A. (eds), Humans as Components of Ecosystems: The Ecology of Subtle Human Effects and Populated Areas. Springer-Verlag, pp. 141–157.
Comision Asesora Ambiental de la Presidencia de la Republica del Ecuador (CAAM) 1996. Desarrollo y problematica ambiental del area del Golfo de Guayaquil, 105–110.
Comision de Estudios para el desarrollo de la Cuenca del Rio Guayas (CEDEGE) 2000. Presented by Jose M. Martin at the Conference of 25th anniversary of CEDEGE. CEDEGE y la planificacion de recursos hidraulicos en Ecuador.
Comision de Estudios para el desarrollo de la Cuenca del Rio Guayas (CEDEGE) 2001. Plan integral de gestion socio-ambiental de la Cuenca del Guayas y Peninsula de Santa Elena. Resumen Ejecutivo, 149 pp.
Cleveland C.C., Townsend A.R., Schimel D.S., Fisher H., Howarth R.W., Hedin L.O., Perakis S.S., Latty E.F., Von Fischer J.C., Elseroad A. and Wasson M.F. 1999. Global patterns of terrestrial biological nitrogen (N2) fixation in natural ecosystems. Global Biogeochem. Cycles 13: 623–645.
Cronan C.S., Piampiano J.T. and Patterson H.H. 1999. Influence of land use and hydrology on exports of carbon and nitrogen in a Maine river basin. J. Environ. Quality 28: 953–961.
Downing J.A., McClain R.T., Melack J.M., Elser J., Rabalis N.N., Lewis W.M. Jr., Turner R.E., Corredor S.D., Yanez-Arancibia A., Kopaska J.A. and Howarth R.W. 1999. The impact of accelerating land use change on the N-Cycle of tropical aquatic ecosystems: current conditions and projected changes. Biogeochemistry 46: 109–148.
ECLAC, Economic Comission for Latin American and the Caribbean 1999. Statistical Yearbook for Latin America and the Caribbean 1998, Chile. ISSN 10114-0697.
Falconi-Benitez Fander 2000. An integrated assessment of changes of land-use in Ecuador. Paper presented in the Advances in Energy Studies, Porto Venere 2000.
Food Agriculture Organization 2002. FAOSTAT, statistical database. http://www.apps.fao.org/.
Filoso S., Martinelli L.A., Williams M.R., Lara L.B., Krusche A., Ballester M.V., Victoria R. and de Camargo P.B. 2003. Land use and nitrogen export in the Piracicaba River basin, Southeast Brazil. Biogeochemistry 65: 275–294.
Galloway J.N., Schlesinger W.H., Levy H. II, Michaels A. and Schnoor J.L. 1995. Nitrogen fixation: anthropogenic enhancement-environmental response. Global Biogeochem. Cycles 9: 235–252.
Hall Charles A., Ko J.-Y., Lee C.-L. and Wang H.Q. 1998. Ricardo Lives: The Inverse Relation of Resource Exploitation Intensity and Efficiency in Costa Rican Agriculture and its Relation to Sustainable Development. Advances in Energy Studies Conference, Musis, Roma.
Hall C.A.S. and Hall M.H.P. 1993. The efficiency of land and energy use in tropical economies and agriculture. Agricult., Ecosyst. Environ. 46: 1–30.
Hallock J.L. Jr., Tharakan P.J., Hall C.A.S., Jefferson Michael and Wu W. 2004. Forecasting the limits to the availability and diversity of global conventional oil supply. Energy 30(10): 1673–1696.
Harper D.M. and Stewart W.D.P. 1987. The effects of land use upon water chemistry, particularly nutrient enrichment, in shallow lowland lakes: comparative studies of three lochs in Scotland. Hydrobiologia 148: 211–229.
Howarth R.W., Billen G., Swanney D., Townsed A., Jaworski N., Lajtha K., Downing J.A., Elmgreen R., Caraco N., Jordan T., Berendese F., Freney J., Kudeyarov V., Murdoch P. and Zhao-Liang Z. 1996. Regional nitrogen budgets and riverine N & P fluxes for the drainage to the North Atlantic Ocean: natural and human influences. Biogeochemistry 35: 75–139.
Houghton R.A. 1994. The worldwide extent of land-use change. BioScience 44: 305–313.
Tiessen H., Chacon P. and Cuevas E. 1994. Phosphorus and nitrogen status in soils and vegetation along a toposequence of Dystrophic Rainforests on the Upper Rio Negro. Oecologia 99: 145–150.
Instituto Nacional de Hidrologia y Meteorologia (INAMHI), Anuarios meteorológicos. Instituto Nacional de Estadísticas y Censos (INEC) 2001. VI Censo Nacional de Población y Vivienda del 2000.
Instituto Nacional de Estadísticas y Censos (INEC) 2002. III Censo Nacional Agropecuario 2001.
Instituto Nacional de Investigaciones Agropecuarias (INIAP) 2000. Costos de las tecnologias de los principales cultivos del Ecuador, 124 pp.
Jaworski N.A., Groffman P.M., Keller A.A. and Prager J.C. 1992. A watershed nitrogen and phosphorus balance: the Upper Potomac River Basin. Estuaries 15: 83–95.
de Koning G.H.F. 1999. Spatially explicit analysis of land use change: a case study for Ecuador. Thesis. Wageningen University Agricultural University, 172 pp.
Lacerda L.D., Kremer H.H., Kjerfve B., Salomons W., Marshall J.I. and Crossland C.J. 2002. South American Basins: LOICZ Global Change Assessment and Synthesis of River Watershed — Coastal Sea Interaction and Human Dimensions. LOICZ Reports & Studies No. 21, Volume 1: ii+95 pp, Volume 2: ii+127 pp, LOICZ, Texel, The Netherlands.
Lewis W.M. Jr., Melack J.M., McDowell W.H., McClain M. and Richey J.E. (1999). Nitrogen yields from undisturbed watersheds in the Americas. In: New Perspectives on Nitrogen Cycling in the Temperate and Tropical Americas, pp. 149–162.
McDowell W.H. and Asbury C.E. 1994. Export of carbon, nitrogen, and major ions from three tropical montane watersheds. Limnol. Oceanogr. 39: 111–125.
Merriam J., McDowell W.H. and Currie W.S. 1996. A high-temperature catalytic oxidation technique for determining total dissolved nitrogen. Soil Sci. Soc. Am. J. 60: 1050–1055.
McKee L. and Eyre B.D. 2000. Nitrogen and phosphorus budget for the subtropical Richmond river catchment, Australia. Biogeochemistry 50: 207–239.
Ojima D.S., Galvin K.A. and Turner B.L. II 1994. The global impact of land-use change. BioScience 44: 300–304.
Organizacion Panamerica para la Salud (OPS) — Division de Salud y Ambiente 1994. Manual de evaluacion y manejo de sustancias toxicas en aguas superficiales. Seccion 3: Evaluacion preliminaria rapida, Lima, Peru.
Pierzynski G.M., Hettiarachi G.M. and Koelliker J.K., 1997. Methods for assessing the Impacts of Soil Degradation on Water Quality. Methods for assessment of soil degradation, pp. 513–545.
Skole D.L., Chomentowski W.H., Salas W.A. and Nobre A.D. 1994. Physical and human dimensions of deforestation in Amazonia. BioScience 44: 314–324.
Smaling E.M.A. and Oenema 1997. Estimating nutrient balances in agro-ecosystems at different spatial scales. Methods for assessment of soil degradation. pp. 229–250.
Southgate D. and Whitaker M. 1994. Economic Progress and the Environment: One Developing Country’s Policy Crisis. Oxford University Press.
Sibbesen E. 1989. Phosphorus cycling in intensive agriculture with special reference to countries in the temperate zone of Western Europe. In: Tiessen H. (ed.), Phosphorus cycles in terrestrial and aquatic ecosystems. Regional workshop 1: Europe, SCOPE/UNEP Proceeding, University of Saskatchewan, Saskatoon, Canada, pp. 112–122.
Sibbesen E. and Rutger Metzger A. 1995. Phosphorus balance in the European Agriculture. In: Tiessen, H. (ed.), Phosphorus in the Global Environment: Transfers, cycles and management. SCOPE Vol 54, pp. 43–59.
Stoorvogel J.J. 1993. Optimizing land use distribution to minimize nutrient depletion: a case study for the Atlantic Zone of Costa Rica. Geoderma 60: 277–292.
Twilley R., Gottfried R., Rivera-Monroy V., Zhang W., Montano-Armijos M., Bodero A., 1998. An approach and preliminary model of integrating ecological and economic constraints of environmental quality in the Guayas River estuary, Ecuador. Environmental Science and Policy, 271–288.
USGS 2003. United States Geological Survey, Elevation derivative database. Online URL: http://www.edcdaac.usgs.gov/gtopo30/hydro/.
Valiela I. and Bowen J.L. 2002. Nitrogen sources to watersheds and estuaries: role of land cover mosaics and losses within watersheds. Environ. Pollut. 118: 239–248.
Vallis I. and Keating B.A. 1997. Uptake and loss of fertilizer and soil nitrogen in sugarcane crops. Proc. Aust. Soc. Sugar Cane Tech.
Van Breemen N., Boyer E.W., Goodale C.L., Jaworski N.A., Paustian K., Seitzinger S.P., Lajtha K., Mayer B., Van Dam D., Howarth R.W., Nadelhoffer K.J., Eve M. and Billen G. 2002. Where did all the nitrogen go? Fate of nitrogen inputs to large watersheds in the northeastern USA. Biogeochemistry 57/58: 267–293.
Van den Bosch H., de Jager A. and Vlaming J. 1988. Monitoring nutrient flows and economic performance in African farming systems (NUTMON) II. Tool development. Agric., Ecosyst. Environ. 71: 49–62.
Van Ittersum M.K., Rabbinge R. and Van Latesteijn H.C. 1998. Exploratory land use studies and their role in strategic policy making. Agricult. Syst. 58(3): 309–330.
Velthof G.L., Oenema O., Postma R. and van Beusichem M.L. 1997. Effects of type and amount of applied fertilizer on nitrous oxide fluxes from intensively manged grassland. Nutrient Cycling Agroecosyst. 46: 257–267.
Vitousek P.M., Aber J.D., Howarth R.W., Likens G.E., Matson P.A., Schindler D.W. and Tilman D.G. 1997. Human alteration of the global nitrogen cycle: sources and consequences. Ecol. Appl. 7(3): 737–750.
Webb B.W., Phillips J.M. and Walling D.E. 2000. A new approach to deriving ‘best estimate’ chemical fluxes for rivers draining the LOIS study area. Sci. Total Environ. 251/252: 45–54.
Yanez-Arancibia A & Lara-Dominguez A.L. 1998. Mangrove Ecosystems in Tropical America: Structure, Function, and Management. EPOMEX Scientific Series 3, University of Campeche, Mexico.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2006 Springer
About this chapter
Cite this chapter
Borbor-Cordova, M.J., Boyer, E.W., Mcdowell, W.H., Hall, C.A. (2006). Nitrogen and phosphorus budgets for a tropical watershed impacted by agricultural land use: Guayas, Ecuador. In: Martinelli, L.A., Howarth, R.W. (eds) Nitrogen Cycling in the Americas: Natural and Anthropogenic Influences and Controls. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-5517-1_7
Download citation
DOI: https://doi.org/10.1007/978-1-4020-5517-1_7
Publisher Name: Springer, Dordrecht
Print ISBN: 978-1-4020-4717-6
Online ISBN: 978-1-4020-5517-1
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)