Dr. Paul's Research Perspectives
Organic challenges conventional for yield
potential in current Rodale tests
Decades of soil improvements produce better soil quality and allow organic corn production to move beyond yield parity, while providing better resilience in drought and wet years.

By Dr. Paul Hepperly

editors' NOTE:

As New Farm Research and Training Manager at The Rodale Institute®, Dr. Paul Hepperly has been a regular contributor to NewFarm.org for some time, providing research updates, op-ed pieces, and white papers on topics like carbon sequestration in organic farming systems.

None of those venues do full justice to the range of Paul's experience, however. Paul grew up on a family farm in Illinois and holds a Ph.D. in plant pathology, an M.S. in agronomy and a B.S. in psychology from the University of Illinois at Champaign-Urbana. He has worked for the USDA Agricultural Research Service, in academia, and for a number of private seed companies, including Asgrow, Pioneer, and DeKalb. He has overseen research in Hawaii, Iowa, Puerto Rico, and Chile, and investigated such diverse crops as soybeans, corn, sorghum, sunflowers, ginger, and papaya. He has witnessed the move toward biotech among the traditional plant breeding community and the move toward organics among new wave of upcoming young farmers. Before coming to the Rodale Institute Paul worked with hill farmers in India to help them overcome problems with ginger root rot in collaboration with Winrock International.

Now we've decided to give Paul his own column, in which he can report on agricultural research from around the world and reflect on its relevance to The Rodale Institute's research program and to the progress of sustainable agriculture more generally in light of his own broad perspective. Enjoy.

How to contact Paul

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Kutztown, PA 19530
610-683-1420

Posted February 16, 2007: Since 1981, the Rodale Institute has conducted the longest-running scientifically controlled comparison of organic and conventional crop production systems in the United States. When it comes to drawing conclusions from this research, timing is everything. What looked good in the short term doesn’t look so good now. From this point in time, it’s the organic farming practices that now stand out for multiple long-term benefits—and for increasing yield potential.

The Rodale Institute’s Farming Systems Trial (FST) is designed as a scientifically valid suite of plots covering 13 acres of virtually flat land with moderate drainage and shallow top soil. The conventional system uses land-grant recommendations and a conservation tillage regime typical of our region. Research has been conducted in collaboration with the United States Department of Agriculture’s Agricultural Research Service (ARS) and researchers from several land-grant universities.

Conventional corn yield was superior in our early tests, during the years when the soils being farmed organically were going through the transition process and building up their biological activity. Soon, the organic plots entered a long phase (1985 until 1993) when yield was statistically the same as the side-by-side plots of conventionally farmed soil.

Continuous soil improvements after two decades have resulted in dramatic environmental improvements, production resiliency during weather extremes, and—averaged over the past 12 seasons—slightly higher corn yields in the organic system. From 1995 to 2006 organic corn yields (119 bushels per acre) have out-yielded conventional corn yield (110 bu/A). This period included both severe drought years and a record wet summer. (The yield difference between organic and conventional is statistically significant at P=0.03.)

The beginning years

If we had stopped the FST comparison work after two or three years, we might have been tempted to agree with Nobel Laureate Norman Borlaug. He has claimed that organic agriculture can never compete with the yield of high-input conventional agriculture.

But with time, our research tells a very different story. From 1985 to 1993, the FST mini-fields showed no overall difference in corn and soybean yields between the organic and conventional systems. Moreover, in drought years with less than 200 mm (7.9 inches) of rain in July and August, corn yields were 28 to 34 percent higher in the organically managed soils.

Starting with the 2004 crop season—after 23 years of organic and conventional management, and the growth of resulting soil differences—the plots were farmed under a common corn, soybean and wheat crop rotation. That summer, a record rainfall resulted in a harvest that showed organic corn had significantly higher yield (146 bu/A organic, 129 bu/A conventional) and higher grain protein content than the conventional system. (This yield difference was statistically significant at P=0.10.)

This transformation of the organic fields is somewhat like the race of the tortoise and hare, but in this case the organic systems now look to be winning the race on three fronts: soil quality, drought tolerance and overall yield.

In our trials we have noted that soil quality—in terms of carbon, total nitrogen, and biological activity—has increased in each area under organic management, but not under the conventional system. These soil changes explain why organic soils have improved over time in our testing environment.

Gradual elevation of soil organic matter with continuous use of soil-building practices is the foundation for many changes that improve the productive capacity and biological resiliency of organic systems.

It’s in this way that organic soil can potentially out-compete conventional production systems over the long run. It takes time to use healthy soil practices to restore the biological life, but this time creates a biological and structural foundation for future improvements.

A new reality?

Our research is from one farm in Pennsylvania, but we believe the principles it documents have much broader application to similar growing areas around the world. Despite the nagging disbelief of chemical agriculture proponents, The Rodale Institute’s research shows organic agriculture has as much potential to actually feed the world in a sustainable manner as does conventional commodity crop farming. Modern research has increased the capacity of traditional organic farming beyond that which had fed civilizations for 6,000 years.

Moreover, in the long-term perspective that includes peak oil and diminishing groundwater resources, a bigger question looms: In the span of recorded agricultural history, can the relatively recent advent of high-input, chemically based agriculture continue much longer without excessively degrading the very natural environment we all depend upon?

Hard scientific evidence shows that agricultural productivity can be judiciously enhanced through long-proven, ecologically sound, soil-improvement methods without resorting to toxic chemicals.

This new paradigm of productivity offers this potential: if we want to help all farmers to develop systems which will, in time, improve their yields while they increase the quality of food produced, and while they decrease their input costs and environmental impact, organic methods are needed by all farmers.

We will continue to monitor our FST plots to see if the indicators of the past three years that show organic advantage are maintained, strengthened or changed. We will also foster the application of regionally adapted cover cropping and crop rotation practices useable in any farming approach to support a better future for farmers and for all food consumers.

By focusing on the basics of soil improvement, we can avoid the pitfalls and dependencies of chemically intensive agriculture as we offer the world a true green revolution.