DR. Don's Research Updates
November 15, 2002: Drought adaptiveness of organic crop systems and the future of food production

By Don Lotter, Ph.D., post-doctoral researcher, Rodale Institute

Editor's NOTE

In addition to analyzing data from our research trials and developing new domestic and international research initiatives, Don reviews dozens of research studies each week. He'll present the most interesting of his findings every week on the web site.

As global climate change increases, there are predictions of increased climatic instability leading to increased incidence and severity of droughts and flooding and other extreme climatic events (Sombrock and Gommes, 1996; Weiss and Bradley, 2001). Cropping stability and the ability to buffer yields during periods of climatic adversity are critical factors in agriculture’s ability to support society in the future.

Organic crop systems have a track record of better performance than conventionally managed systems in this area. A number of studies have shown that under drought conditions crops in organically managed systems produce higher yields than comparable crops managed conventionally (Dormaar et al., 1988; Stanhill, 1990). This advantage can result in organic crops outyielding conventional crops by 70-90% under severe drought conditions (Lockeretz et al., 1981; Wynen, 1994; Petersen et al., 1999; Lotter, 2003). Others have shown that organically managed crop systems have lower long-term yield variability, i.e higher cropping system stability (Henning, 1994; Peters, 1994; Smolik et al., 1995). Swift (1994) proposed that assessments of crop performance should include analysis of two components – non-declining crop trends, and stability of yield from cycle to cycle.

The results of the 21-year Rodale Farming Systems Trial, in which organic and conventional corn-soybean rotations are compared, verify these research findings. In all six drought years in Pennsylvania 1988, 1994, 1995, 1997, 1998, and 1999 – the organic corn outyielded the conventional corn, by as much as 40%.

The future of food production will entail adapting to the changing environment, as biological systems have always done via natural selection. As an example, because crops use 70% of pumped water, impending shortages of aquifer-sourced irrigation water in Asia (Brown, 2003) will force the use of drought-adapted crop systems. Selection pressure will be favoring crop systems that are better adapted to stress, and organic agriculture will be there to fill that niche.

1. Brown, L. R. 2003. Water deficits growing in many countries. Earth Policy Institute Update #15, www.earth-policy.org.
2. Dormaar, J. F., C. W. Lindwall, and G. C. Kozub. 1988. Effectiveness of manure and commercial fertilizer in restoring productivity of an artificially eroded dark brown chermozemic soil under dryland conditions. Canadian Journal of Soil Science, 68:669-679.
3. Henning, J. 1994. Economics of organic farming in Canada. In: The Economics of Organic Farming, N. H. Lampkin and S. Padel, Editor. CAB: Wallingford, UK. p. 3-8
4. Lockeretz, W., G. Shearer, and D. H. Kohl. 1981. Organic farming in the Corn Belt. Science, 211:540-546.
5. Lotter, D. W. 2003. Organic agriculture. J. Sust. Agric., 21 (4).
6. Peters, S. E. 1994. Conversion to low-input farming systems in Pennsylvania, USA: an evaluation of the Rodale Farming Systems Trial and related economic studies. In: The Economics of Organic Farming, N. H. Lampkin and S. Padel, Editor. CAB: Wallingford, UK. p. 265-284
7. Petersen, C., L. Drinkwater, and P. Wagoner. 1999. The Rodale Institute Farming Systems Trial: the first 15 years. The Rodale Institute. Kutztown, PA.40 p. www.rodaleinstitute.org
8. Smolik, J. D., T. L. Dobbs, and D. H. Rickerl. 1995. The relative sustainability of alternative, conventional and reduced-till farming system. American Journal of Alternative Agriculture, 10 (1):25.
9. Sombrock, W. G. and R. Gommes. 1996. The climate change-agriculture conundrum. In: Global climate change and agricultural production, F. A. Bazzaz and W. G. Sombroek, Editors. FAO; Wiley: Chichester; New York. p. 1-14
10. Stanhill, G. 1990. The Comparative Productivity of Organic Agriculture. Agriculture, Ecosystems and Environment, 30 (1-2):1-26.
11. Swift, J. J. 1994. Maintaining the biological status of soil: a key to sustainable land management? In: Soil resilience and sustainable land use: proceedings of a symposium held in Budapest; 28 September to 2 October 1992, including the Second Workshop on the Ecological Foundations of Sustainable Agriculture (WEFSA II), D. J. and I.Szabolcs Greenland, Editor. CAB International: Wallingford, UK. p. 235-247
12. Weiss, H. and R. S. Bradley. 2001. What drives societal collapse? Science, 291 (5506):988.
13. Wynen, E. 1994. Economics of organic farming in Australia. In: The Economics of Organic Farming, N. H. Lampkin and S. Padel, Editor. CAB: Wallingford, UK. p. 185-199