PRINT Unseen treasure, Part 2: Lost research shows organics benefit root growth

Dr. Paul's Research Perspectives
Unseen Treasure Part 2: "Lost research” shows organics benefit root growth
Rodale Institute and Cornell site results also validate damage done by fertilizer and herbcides.

By Paul Hepperly, PhD, and Dave Wilson

Missed Part 1?

We began this two-part look at roots last month with Unseen Treasure Part 1: Giving due respect to the robust role of roots. There we made the point that although they are virtually invisible and always under-appreciated, roots are a major factor in agriculture: “Without roots there are no shoots.” We established the tremendous root-enhancing potential of mycorrhizal fungi in positive soil environments, and documented what roots need to access soil minerals to benefit crops.

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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610-683-1420

September 15, 2006: As scientists we often lament on the mass of good research with relevant information that never sees the light of day. In organic agriculture this is an even greater problem for two reasons: 1) there is a critical need for peer-reviewed information on healthy certified organic systems to overcome the organic research deficit; 2) much of the data recorded is functionally lost due to more conventionally minded reviewers who have no basis for appreciating the profound role of biologically based organic practices on crop productivity.

In some ways The Rodale Institute Farming Systems Trial helps to turn the tables a bit since there are few conventional studies which have stayed the course for 26 years, as has this trial, giving it a sort of “super validity.”

This spring I happened upon an exhaustive study of corn root systems done at the Rodale Institute in collaboration with researchers at Cornell University. The study was novel for its use of video cameras to directly measure corn root proliferation in the soil at different depths in experimental fields.

Working with Rodale Institute researchers, Dr. Victor N. Bushamuka (a World Bank Graduate Research Fellow) implemented the study using the video camera process developed by his advisor, Cornell’s Dr. Richard W. Zobel. From 1989 to 1991, data points were taken from three sites at the Rodale Institute and two sites in New York to see how alternative agricultural practices affect the root system. To date this work is only published as a Cornell University thesis despite its novel method and dramatic results. ("Response of maize root growth to tillage, fertilization, and weed control systems under conventional and sustainable cropping systems.” 1993. Master’s Thesis. 181pp.)

Coming to grips with an inconvenient truth

You would think that a study like this would be enthusiastically publicized, analyzed and debated, but this has not been the case. The data irrefutably supports a startling conclusion: alternative agricultural practices support dramatically increased root growth. I believe this challenging conclusion is why these findings haven’t yet made their way into scientific literature.

This is science that deserves to make an impact, but first it has to escape the thesis section of the Cornell Library. So here goes:

The FST is our long-term trial comparing three cash-grain systems: two organic rotations and one non-organic, corn-soybean rotation, based on the current recommendations for soybean and cash-grain corn production from The Pennsylvania State University. Compared in randomized and replicated plots are an organic system where manure supplies fertility, an organic system where legume crops provide fertility and the “conventional” cash-grain system.

The FST results reported by Zobel and Bushamuka showed that the livestock (manure) organic system and the legume organic systems both significantly increased the presence of lateral corn roots. The manure system doubled the lateral roots of conventional corn and soybeans measured in the first 25 cm (10 inches) of soil. In just 10 years of organic transition management (1981-1991), the amounts of roots were sharply increased in both organic systems compared to the conventional corn/soybean row-crop system.

Although it may seem obvious that roots are a good thing, there is a group of scientists that argue, conversely, that roots represent a waste of plant energy which could be better portioned to plant grain yield. This seems to me like saying legs are over-rated for running.

It’s true, I suppose, that you wouldn’t need roots if you didn’t need to support the plant, feed the plant, and get water into the plant. However, under natural field conditions, those are real needs that crops have.

In data from the New York (Aurora) site, Zobel and Bushamuka looked at the factors of cultivation versus herbicide and manure versus fertilizer in all combinations. Like the Rodale Institute site, at Aurora it was evident that manure was superior to fertilizer for favoring lateral root density, and cultivation was superior to herbicide.

Most dramatic was the data results showing that combining the impacts of fertilizer and herbicide applications proved synergistically negative for corn root proliferation at the 30-cm (12-inch) depth.

Looking at the devastating reduction of roots when fertilizer is combined with herbicide in these samples, we can appreciate the wisdom of the early organic pioneers who disliked reliance on chemical inputs and advised against their use. Indeed, long-term experimentation and experience would show a wide range of subtle negative side-effects not originally envisioned by the proponents of these “crop protection and enhancement materials” at the beginning of their unplanned experiment with the food system.

If I were a farmer entering a drought—or a corn plant, for that matter—I would like the cushion of having more, not fewer, roots. Considering there are thousands of synthetic chemicals that interact with each other in unknown ways, the best way to avoid unexpected negative consequences from these is to avoid and reduce their use. Even their proponents look at them more and more as necessary evils rather than as the easy solutions they once thought.

As long as roots have the last say, using more natural biological management techniques and fewer chemical inputs is the way to improve plant responses to the growing environment as we know it.