Agriculture and Water: Harvesting Water before Harvesting the Crop

Dr. Hans Schreier
Institute for Resources and Environment, UBC

Thursday October 17, 2002
7 pm, Simon Fraser University at Harbour Centre
Room 7000

Agricultural is rapidly emerging as a dysfunctional industry. Over the past 40 years the industry has been very successful in growing enough food to meet the needs of the growing world population. At the same time one billion people engaged in agriculture are amongst the poorest in the world and do not have sufficient food to meet their daily needs. Unequal access to resources, lack of input, poor access to markets and poor distribution systems is to a large extent responsible for this dichotomy. Food prices have consistently declined because the industry is heavily subsidized and at the same time there has been a continuous shift towards very large corporations that control most inputs and operate at continental and global scales. The main factors that have contributed to the success of producing sufficient global food supplies are high external input and very large dependency on irrigation. Both have had a tremendous impact on water resources. About 17% of the agricultural lands are irrigated producing about 40% of the food globally. This translates into 75% of the available freshwater in the world that is used for agricultural production. At the same time agriculture has now emerged as the largest contributor to water quality deterioration.
What does this mean for the future? Recent forecasts (World Bank 2001) suggest that the food production have to double over the next 30 years in order to meet the food demands by global population growth. Probably the most critical factor is access to water resources. Most of the easily accessible water resources are already in use and the competition for the freshwater resources from other users is increasing rapidly. The water resources are fixed and there are virtually no places on earth where water is evenly distributed. At any one time there is usually too much or insufficient water available for all uses. However the greatest concern is the emerging conflict between urban and agricultural uses.

There are three main reasons why demand for freshwater by the rapidly growing urban centers are increasing. The number of cities with population greater than 1 million will increase from 300 in 2000 to 500 by 2015 and this means large demands for drinking and domestic water. At the same time the recreational demand by urbanites is also increasing rapidly and this is known to be a very water consumptive industry. The most critical concern however is the shift in food consumption by the urban population from staple food to a meat and fish dominated diet. This creates the greatest pressure on agricultural use of water, because meat consumption is exceedingly water consumptive. It has been estimated that 15,000-30,000 L of water is needed to produce 1 kg of beef, and 3000-4000 L are needed to produce one kg of chicken meat. In contrast only about 1000 L are needed to produce one kg of cereals (Gleick 2000). Increases in meat consumption have exceeded population growth in most urban areas and to meet this demand agriculture has shifted meat production from grazing into stall feeding in concentrated feedlot operations. These industrial operations are still treated as typical agricultural operations where the waste is applied to the land with the hope that the soils and microbial population will take care of decomposition in a benign way. Considering that a full-grown cow produced 6-7 times as much nitrogen in the waste as a human being it is evident that a typical feedlot of 40,000 animals produced waste that is equivalent of a human population of 240,000 people. None of this waste is treated and since the economics of manure transportation is poor, little manure is shipped over long distances (Hatfield and Steward, 1998). Over applications of manure in the vicinity of large livestock operation is now a common problem that has reached global proportions and, given the unfavorable economic conditions for agricultural production, it is unlikely that things will change in the coming years. What is needed is a meat tax that will be used for waste treatment in intensive agricultural operations. This is likely the only way we will be able to deal with this amount of waste that is approximately 3 times larger than all the human waste generated globally.

Since agriculture is the largest user of freshwater and the greatest contributor of waste the pressure for water conservation, improved efficient in water use and waste treatment is enormous. Water harvesting and the use of drip irrigation are spreading quickly in the developing world but this alone is insufficient to deal with the problems of waste. What is needed is a radical shift in consumption patterns, treatment of waste from industrial operations, and more extensive use of wastewater in agriculture. None of the challenges are easy to accomplish. The legal system is very poorly equipped to deal with non-point source pollution from agriculture and changing the appetite for meat by the urban population is equally difficult control.

Probably the greatest challenge for agriculture is the increasing variability in climate. There is an ever growing need to increase water storage but this is becoming more difficult because the most suitable reservoir sites are already used and concerns about obstructions of passage ways for fish and navigation, and displacement of people is making it increasingly difficult and undesirable to built more reservoirs. At the same time many groundwater aquifers in India, China, the United States and elsewhere (Postel 1999) are over-used and water yields are declining. Climate change is causing the greatest concern because there is now convincing evidence that glaciers globally are melting faster than the experts have predicted (Haeberli et al. 1999) and this means greater summer runoff in many streams for the coming years. However, this will result in a false assumption for water security. For example the glaciers on Mt. Kilimanjaro, at the current rate of melting, are expected to disappear within 10-15 years. This means lots of meltwater in the next few years but radically altered conditions thereafter. We now have to consider water harvesting before crop harvesting. There are many opportunities to do it effectively particularly in the developing world. Examples will be presented on how to do this effectively in the developing world to improve food security. However, even with a massive reorganization of water allocation and an concentrated emphasis on use efficiency, doubling food production over the next 30 years represent a formidable challenge. At the same time we have to increase food self-sufficiency for a billion rural people that have so far been deprived of sufficient land and water resources to improve their livelihood. A concerted effort is needed by all users (urban and agriculture) to reduce demand. Water equity for people, animals, fish and agriculture for the first time in history is now a global issue that is the challenge for the 21st century. Simply taking an industrial approach or dealing with water on a sector by sector basis is clearly ineffective. Water has to be managed on a watershed basis in order to assure equity for all. Water pricing, water balances, conflict resolutions, water reallocations, reuse, and conservation are the topics that will be dominating agriculture in the coming years.

Selected References:
Berka, C., H. Schreier, K. Hall. 2001. Linking water quality with agricultural Intensification in a rural watershed. Water, Air, and Soil Pollution, 127(1/4): 389-401
Gleick, P.H. 2000. The World’s Water 2000-2001. The Biennial Report on Freshwater Resources. Island Press, Washington, D.C. 215 pp.
Gleick, P.H. 1998. The World’s Water 1998-1999. The Biennial Report on Freshwater Resources. Island Press, Whasington, D.C.
Haeberli, W., Frauenfelder, R., Hoelzle, M. and Maisch, M. 1999. On rates and acceleration trends of global glacier mass changes. Geografiska Annaler, 81A:585-591
Hatfield, J.L. and B.A. Steward. 1998. Animal Waste Utilization: Effective use of Manure. Ann Arbor Press, Chelsea, MI.
Owens-Viani, L., A.K. Wong, and P.H. Gleick. 1999. Sustainable use of Water:California Success Stories, An overview to Water Recycling in California. Pacific Institute for Studies in Development, Environment and Security. Oakland, CA.
Postel, S.L.1999. Pillars of Sand:Can the irrigation miracle last? W.W. Norton, New York.
Ritter, W.F., and A. Shirmohammadi. 2001. Agricultural Nonpoint Source Pollution. Lewis Publishers, Boca Raton, 342 pp.
Schreier, H., S. Brown, R. Bestiber. 2002: The Himalayan-Andean Watershed Project. Nine multi-media CD-ROMs, International Development Research Centre (IDRC) Ottawa.
Smil, 2000 Feeding the World: A Challenge for the Twenty-First Century. MIT Press, Cambridge, MA. 360 pp.
Spangenberg, N.E. 2002. The New Economy of Water. Water Resources Impact, Vol. 4(1) 2-29.
Work Bank, 2001. Science and Technology in Securing Food for the Next Century: Challenges, Issues and Options. World Bank, Washington, D.C.


Hans Schreier is a professor at the Institute for Resources and Environment, at the University of British Columbia. His research focuses on watershed management, land-water interactions, water and soil pollution, and GIS. He has worked extensively in watershed studies in the Himalayan and Andean regions, as well as in Brazil, Honduras, Vietnam, Mongolia and British Columbia. He was recognized by the international Development Research Centre (IDRC) in 1996 for his contribution to development. He also received a Senior Sabbatical fellowship awards by IDRC in 2000 which allowed him to review research projects in 14 different developing countries and teach watershed courses in South America and Asia. He is also a member of the Drinking Water Review Panel of British Columbia. He has recently completed the Himalayan-Andean Watershed Project, that highlighted and compared watershed projects in Bolivia, Peru, Ecuador, Bhutan, Nepal, and China. He has also developed a distance education watershed certificate that includes graduate level courses for professionals. This certificate has reached a global audience with participants from more than 20 different countries, and is proving to be an effective way to foster water resources management education in the developing world.

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