Examples of Organic Research

Examples of Organic Research

The following list of research studies is far from comprehensive. It is not designed to identify selected studies as “the best research available.” Instead, this list is meant to show the depth and diversity of research being conducted on organic agro-ecosystems.

Comparisons of organic and conventional agriculture

Temple, Steve. 2000. The Transition from Conventional to Low-Input or Organic Farming Systems: Soil Biology, Soil Chemistry, Soil Physics, Energy Utilization, Economics, and Risk. Western SARE. Final Report - November 2000. www.sarep.ucdavis.edu/Grants/Reports/Temple/temple88-225.htm

A two-year rotation of tomatoes and wheat was more profitable than either organic or low-conventional-input four-year rotations that included processing tomatoes, safflower, dry beans, wheat, and corn. However, the organic system had better water infiltration and exhibited a substantially greater build-up of organic matter in the soil. Based on output-input ratios, the low-input system is the most energy-efficient farming system, while the conventional two-year rotation is the least efficient.

Delate, Kathleen, Michael Duffy, Craig Chase, Ann Holste, Heather Friedrich, and Noreen Wantate. 2003. An economic comparison of organic and conventional grain crops in a long-term agroecological research (LTAR) site in Iowa. American Journal of Alternative Agriculture. Vol. 18, No, 2. p. 59–69.

A long-term study was established in 1998 to examine the agronomic and economic performance of conventional and organic systems. After three years of production (1999–2001), returns for corn within the organic corn-soybeanoat and corn-soybean-oat-alfalfa rotations were significantly greater than conventional corn-soybean rotation returns. Organic soybean returns were significantly greater than conventional soybean crop returns in the corn-soybean rotation.

Production Economics

Evans, William B., Kenneth W. Hood, Keri L. Paridon, and Peter M. Hudson. 2005. Organic Vegetable Yield and Economics Show Promise in a Mississippi Trial. American Society for Horticultural Science. Annual Conference. July 18-21, 2005. Las Vegas, NV.

Yield, input, and economic data from research plots in central Mississippi are being used to test the economic potential of organic vegetable crop production. A six-part, multi-year rotation, including winter and summer cover crops, has been set up to generate yield, cost, and economic return data from vegetables produced in Mississippi using methods allowed by the United States Department of Agriculture National Organic Standards and accepted by local growers employing pesticide-free and other similar management methods. Data being collected include labor and input costs, yields, and market prices for harvested crops. Marketable produce is being sold through a grower-retailer at a farmers’ market. During 2004, the first full year of the rotation, 10 vegetable species were included in the plots. Pest pressure has generally been minimal. With one exception, all crops planted produced fair to excellent yields. Crops generating high retail prices in this study include potatoes, snap beans (Phaseolus vulgaris), and leaf lettuce (Lactuca sativa). In the future, the yield and price data being generated will be combined with new and existing cost data to create enterprise and production budgets for use by perspective and existing organic vegetable growers.

Welsh, Rick. 1999. Economics of Organic Grain and Soybean Production in the Midwestern United States. Henry A. Wallace Institute for Alternative Agriculture. Greenbelt, MD.
www.organicaginfo.org/record.cfm?pk_doc_id=2859&doc_num=45

A study conducted by researchers at the land-grant universities in Iowa, Kansas, Minnesota, Nebraska, and two in South Dakota indicates that, even without price premiums, the organic cropping systems were more profitable than the most common conventional system (generally a corn-soybean system) in half the studies, while they were always more profitable than the continuous corn systems. The higher profitability of the organic systems was due to one or more of the following factors: lower production costs, the longer rotations and greater diversity of the organic systems, and the greater drought tolerance of the organic compared to the conventional systems.

Zibilske, Larry, Donald Makus, Joe Bradford, and Nasir Malik. 2004. Sustainable and Organic Management of Selected Fruits and Vegetables. Initiated USDA Agricultural Research Service project at the Integrated Farming and Natural Resources Research Station.
www.ars.usda.gov/research/projects/projects.htm?accn_no=408493

This research seeks to improve organic production systems and to provide guidelines and knowledge for conversion of conventional systems to organic systems. This will be accomplished through the use of a variety of cover cropping systems and by selecting, propagating, and characterizing clones/cultivars that are suited for organic cultivation of olives as a new crop for Texas. Analyses will compare soil and plant health and food quality between organic and conventional systems.

Soil Management

Drinkwater, L.E., P. Wagoner, and M. Sarrantonio. 1998. Legume-based cropping systems have reduced carbon and nitrogen losses. Nature. Vol. 396. p. 262-265.

Nitrogen and carbon losses from organic and conventionally managed fields were analyzed over 15 years. Immobilization of nitrogen by soil organisms and soil organic matter caused nitrogen to accumulate in organically managed fields. Conventional fields had less nitrogen immobilization and 50% more nitrate leaching than the organic plots. The organically managed fields also had greater water infiltration, higher water holding capacity, and less soil erosion than the conventionally managed fields.

Wander, M.M., S.J. Traina, B.R. Stinner, and S.E. Peters. 1994. Organic and conventional management effects on biologically active soil organic matter pools. Soil Science Society of America Journal. Vol. 58. p. 1130-1139.

A 10 year comparison of organically and conventionally managed fields showed higher levels of carbon and nitrogen accumulation in the organically managed soils. Cover-cropped soils had organic matter with a high C/N ratio. This is indicative of high organic matter turnover rates, retention of soil organic matter in chemically stabilized forms, and retention of nitrogen by the soil. Conversely, the conventionally managed soil had the smallest pool of soil organic matter and lowest levels of biological activity.

Lotter, D., Seidel, R., and W. Liebhardt. 2003. The performance of organic and conventional cropping systems in an extreme climate year. American Journal of Alternative Agriculture. Vol. 18, No. 3. p. 146- 154.

The Rodale Institute Farming Systems Trial has been operating since 1981 and consists of three replicated cropping systems, one organic manure based (MNR), one organic legume based (LEG), and a conventional system (CNV). Between 1984 and 1998, five drought years occurred, and in four of them the organic maize out-yielded the CNV by significant margins. In 1999 all crop systems suffered severe yield depressions; however, the organic soybeans yielded more than the conventional plots. The significantly higher water-holding capacity of the organically managed soils is believed to be the primary mechanism for their higher yields.

Davis, Jessica. 2002. Long-term organic farming impacts on soil fertility. OFRF project. Final Report.
www.ofrf.org/publications/Grant%20reports/00.49.15.Davis.Fall00.IB12.pdf

Soil tests from a large, organic mixed-crop farm in Colorado were evaluated over a period of 15 years. This farm used leguminous cover crops and dairy manure as fertility inputs and practiced crop rotations among more than 20 different vegetable crops. During the study period soil fertility and organic matter increased, while pH decreased.

Plant Breeding

Jones, Stephan S. 2004. Development of wheat varieties for organic farmers. OFRF project. Final Report.
www.ofrf.org/publications/Grant%20reports/04.s.36.Jones.pdf

More than 163 historical varieties grown in the Pacific Northwest from 1842 to 1955 were evaluated in the greenhouse and field for emergence, protein quality, baking and milling characteristics, yield, nutrient-use efficiency, vigor, resistance to stripe rust, tolerance to mechanical cultivation, weed suppression ability, and weed competitiveness. Selected varieties were crossed with modern varieties with the objective of selecting varieties best suited for use in organic production systems. Results from field trials involving these crosses indicated that varieties that respond best under organic conditions have different characteristics from those that respond best under conventional practices. This suggests that yield in organic farming systems can be significantly increased by implementing separate plant breeding programs for organic farming systems.

Robertson, Larry. 2004. Breeding Vegetables for Organic Systems: a Federated Approach. Initiated research at the USDA Agricultural Research Service Plant Genetic Resources Unit.
www.ars.usda.gov/research/projects/projects.htm?ACCN_NO=409091

The objective of this cooperative research project is to develop a strong national network capable of developing and delivering quality seed of improved vegetable varieties for organic agricultural production systems. Efforts will be made through additional grants to identify research objectives and research partners to conduct this research to address seed-health issues for organic seed producer.

Weed Management

Christine, Mary Akemo, Mark Bennett, and Emily Regnier. 1998.
Weed control in tomato production using spring-sown cover crops killed by undercutting. HortScience. Vol. 33, No. 3. June. p. 495.

Research on undercutting at Ohio State began in the early in the 1990s. In ongoing research, investigators spring-planted two winter annuals, grain rye and field peas, both as monocultures and as bi-cultures in varying proportions. The cover crops were undercut after two months and tomato seedlings transplanted. Weed suppression was effective for roughly six weeks or until tomato growth was no longer affected by weed competition. Yields were highest in plots that had 50% or more of the cover in peas, apparently in response to greater nitrogen availability. Undercutting loosened the soil, resulting in a positive effect on the transplant growth.

Abdul-Baki, Aref A., and John R. Teasdale. 1997. Snap bean production in conventional tillage and in no-till hairy vetch mulch. Hort- Science. Vol. 32, No. 7. December. p 1191-1193.

The work done by USDA researchers Abdul-Baki and Teasdale is among the most informative on the matter of killed cover crops, highlighting both the potentials and the challenges of this approach. Compared to conventional tillage plots, the killed mulch plots produced higher yields with no additional nitrogen fertilizer. Weed control was managed with a minimal amount of hand weeding in two out of three years.

Schonbeck, Mark, Peggy Elder, and Ralph DeGregorio. 1995. Winter annual cover crops for the home food garden. Journal of Sustainable Agriculture. Vol. 6, No. 2-3. p. 29-53.

A mow-killed mulch of hairy vetch and rye provided better weed control than when these cover crops were tilled into the soil prior to planting. The tilled plots yielded more early in the season, but by the end of the season, yields for the two treatments were not significantly different. Time spent in weed management on the killed-mulch plots was about three-fourths that spent on the tilled plot. Mulched plots also showed better moisture conservation.

Ullrich, S.D., J.R. Teasdale, and M.A. Cavigelli. 2003. Weed Seedbank Dynamics In Organic And Conventional Long-Term Cropping Systems [abstract]. American Society of Agronomy Abstracts. A08-Ullrich412133- Oral.
www.ars.usda.gov/research/publications/publications.htm?seq_no_ 115=151976

Weed management is one of the biggest challenges in organic farming. The Farming Systems Project (FSP) in Beltsville, Maryland, compares five cropping systems, two conventional and three organic. Overall, there has been no long-term increase in the weed seed bank during the first six years. However, there were oscillations in all major species, depending on weather, crop, and weed management success. Comparing the three organic systems in FSP, the seed bank and weed abundance of the dominant species tended to be highest in the two-year rotation, intermediate in the three-year rotation, and lowest in the four-year rotation. This confirms that the more varied and longer the rotation, the lower the population of annual weeds. Organic cropping systems should be designed to offer a variety of mechanisms acting on various stages of the life cycle of annual weeds to regulate weed populations.

Brennan, Eric. 2004. Cover Cropping Practices to Improve Weed and Fertility Management in Organic Production Systems. USDA Agricultural Research Service Annual Report.
www.ars.usda.gov/research/projects/projects.htm?accn_no=407866

Organic production systems are complex and involve interacting factors that affect overall system performance. A multi-year systems study was established on the USDA-ARS certified organic research plot in 2004 to begin to address the effects of cover crop variety and seeding rate on weed management, soil quality, nitrate leaching, and yield in an organic vegetable production system. The first-year data indicated significant treatment effects on weed dynamics, soil moisture storage, and yield and profitability of subsequent vegetable crops. Cover crop mixtures of legumes, cereals, and mustards were effective in weed suppression.

Pest and Disease Suppression

Sams, Carl. 2004. Improving Organic Crop Production with Enhanced Biofumigation and Composting Systems. Southern SARE Research and Education project. Annual Report.
www.sare.org/reporting/report_viewer.asp?pn=LS03-152

Significant yield and disease resistance in tomatoes was achieved with a combination of mustard meal and mushroom compost. Biofumigation using mustard meal or brassica cover crops reduced disease incidence from the fungal disease Southern Blight to 24 to 29% of all plants. In control plots, more than 60% of all plants were affected by this disease. It was also demonstrated that the biofumigation and compost treatment resulted in an increase in soil bacterial activity.

Ristaino, Jean. 2003. Influence of microbial species and functional diversity in soils on pathogen dispersal and ecosystem processes in organic and conventional agroecosystems. Southern SARE Research and Education project. Annual Report.
www.sare.org/reporting/report_viewer.asp?pn=LS01-128

The resistance of conventional, sustainable, and organic agro-ecosystem soils to species invasion and colonization by S. rolfsii were evaluated. Conventional soil fertility amendments included synthetic fertilizers, while organic soil fertility amendments included either composted plant materials, animal manures, or incorporated green manures. Soils amended with organic amendments such as cotton gin trash were more suppressive to southern blight than soils from plots amended with synthetic fertilizers. These soils were colonized less rapidly over time by pathogens, disease incidence was reduced, and yield was higher at harvest. Soils with organic amendments had higher populations of thermophilic organisms.

Delate, Kathleen, Cynthia Cambardella, Brian Lang, John Kennicker, and Heather Friedrich. 2002. Pest Management in Organic Soybeans— Paul Hunter and Wayne Wangness Farms. www.organicaginfo.org/record.cfm?pk_doc_id=3165&doc_num=162

Soybeans at two organic farms were treated with Insecto, Surround, Neemix, or Garlic Gard plus fish oil to determine the effect on aphids and beneficial insects. An untreated control was also monitored. Beneficial insect populations followed the aphid population at both sites. When compared to the other treatments, Neemix generally had the lowest aphid population but also the lowest beneficial population.

Outreach to Organic Producers

Lohr, Luanne, and Timothy A. Parks. 2003. Improving extension effectiveness for organic clients: current status and future directions. Journal of Agricultural and Resource Economics. Vol. 28, No. 3. p. 634-650.

Responses from a national survey of U.S. organic farmers indicated dissatisfaction with the Extension service. Part-time, higher- income organic farmers, who rated highly a variety of private-sector information sources, also rated Extension providers as effective. Farmers in the Northeast and West rated Extension usefulness more highly than did producers in other regions. Extension agents can improve their usefulness to organic farmers by complementing educational and technical services offered by the private sector, and by facilitating farmer information exchange, as well as presenting relevant research findings as they have done traditionally.

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