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Use of compost and a mixed species hay crop are recommended.
For farmers transitioning from a conventional to an organic farming system, decisions made during the three-year transition period can influence important factors of future production, such as soil-borne pathogens, soil fertility, and soil structure. In this study, compost incorporation strongly affected physical, chemical, and biological soil health factors and, overall, the soil food web. Using a mix of perennial hay during the transition was most successful in reducing disease-causing pathogens in the soil. Highest available N and yields occurred in the plots using high tunnel vegetable production.
Materials and Methods
A three-year study was conducted in Wooster, Ohio, to evaluate four common rotational strategies used during transition from a conventional to an organic farming system. The four organic transition strategies evaluated were: 1) tilled fallow, 2) a single planting of mixed species perennial hay, 3) low intensity open field vegetable production, and 4) intensive vegetable production under a high tunnel.
Each transition strategy plot was split in half with 15,000 lbs./ac composted manure applied each year to one half.
At the year of certification, the fields were planted to tomato, with two smaller plots of soybean.
- Compost treatment increased organic matter of soils in all treatments, lowered bulk density, and increased NO3-N, and microbial biomass-N.
- The addition of compost boosted plant vigor for tomatoes for all transition strategies, but had an inconsistent effect on suppression of soil-borne diseases.
- Transition cropping strategy was the main factor influencing bacterial community structure in the soil and the rhizosphere.
- Bacterial communities involved in disease suppression were more abundant in soil previously cropped with hay compared to tilled fallow and low-intensity vegetable production. This was true for both tomato and soybean crops.
- Overall, the mixed hay was the most effective in decreasing damping-off for both tomato and soybean crops.
- Tomato yield during year four was much higher in the high tunnel plot. The hay treatment also showed better yield than the tilled fallow and open field vegetable production.
Why Researchers Think the Hay and High Tunnel Treatments Did Better
Disease suppression might happen in two ways. One involves specific action against pathogen populations. For example, brassicas (cauliflower, kale, turnip, radish, cabbage) suppress soil-borne diseases by exuding sulfur-rich substances that are toxic to many pathogenic soil organisms. And certain species of nematodes eat bacteria and fungi that cause plant diseases. Disease suppression can also occur from high competition for available resources. In both cases, the disease suppression is associated with the overall composition of the microbial community (bacteria, fungi) present in the soil and the rhizosphere.
The hay crop used in this experiment was a combination of Festulolium (a rye fescue hybrid) under-sown with alfalfa, red and white clover, timothy, chicory, orchardgrass, and plantain in equal proportions. Researchers concluded that the above-ground diversity of the hay mix supported an increase in beneficial soil organisms that compete or interfere with pathogens, thus, reducing incidence of disease in future crops.
The highest yields in this study were from the high tunnel plots. While some of the increase resulted from extending the growing season, soil analyses also found a higher level of available N in the high tunnel plots. Researchers think this was a result of maintaining the soil food web in a biologically-active state during the cold early spring months in northern Ohio. The monthly mean soil temperature inside the high tunnels was warmer by 35–41°C from January to May while from July to September it was marginally lower than the outside soil temperature. (Based on top 4 inches.)
For more information on using tunnels in vegetable production, visit the Vegetable Production Systems Laboratory’s Crop Enivronments page.
Prepared by Louceline Fleuridor and Cassandra Brown
Based on summaries of the following papers:
Benítez, MS; Baysal, F.; Rotenberg, D.; Kleinhenz, M.D.; Cardina, J.; Stinner, D.; Miller, S.A.; Gardner, B. B. 2007. Multiple statistical approaches of community fingerprint data reveal bacterial populations associated with general disease suppression arising from the application of different organic field management strategies. Soil Biology and Biochemistry Volume 39, Issue 9, September 2007, Pages 2289-2301
Briar, S.S., Miller, S.A., Stinner, D., Kleinhenz, M.D., & Grewal, P.S. 2011. Effect of different organic transition strategies for peri-urban vegetable production on soil properties, nematode community, and tomato yield. Applied Soil Ecology, 47, pgs 84-91.
Baysal, F; Benitez, MS; Kleinhenz, MD; Miller S.A.; Gardner B.B. 2008. Field management effects on damping-off and early season vigor of crops in a transitional organic cropping system. Phytopathology, Vol. 98, No. 5.
"Soil balancing is complex, it's prevalent, and it's shown the capacity to endure. It also raises very interesting, and sometimes difficult to answer, questions. All of those are reason enough for us to chat, but as we address those questions we’re also very likely to learn about soils, about crops, about farms and farmers, and the people who advise farmers and supply them."
- Matt Kleinhenz, Ohio State, vegetable production specialist
Below are a few notes and quotes from our first two Soil Balancing call-in conversation. Recordings of both calls are available at our website, go.osu.edu/SB-call-in, where you can also find details about our final call-in event on December 12, 2018, 1:30-3:00 p.m. eastern time.
What We Think Soil Balancing Does
“The physical and biological aspects of the soil have more impact on an ultimate yield than actual N, P, and K does. So we're in working with these heavier clay soils. Our main goal is to minimize stress and duration of stress on the crop, so we're trying to preserve yield, because we continually stress this crop and most of the stress on those clay soils comes from water.“
- Joe Nestor, Nestor Ag, LLC (November call-in)
Joe Nestor works as an independent crop consultant in Ohio, Michigan, Indiana. He estimates about 70% of the soils he works with are heavy clay. His main goal using soil balancing is to improve water infiltration for less stress on crops.
“As we reduce flooding in the fields, we end up with a healthier crop in many cases -- a crop that survives, versus a crop that dies out under flooding conditions, and as a result, fewer weeds. When the crop dies or when the crop is not vigorous what grows in those in those areas of the field are weeds primarily. And we've all seen those dead areas in the field that come up in foxtail and other weeds.”
- Doug Doohan, Ohio State, weed specialist (October call-in)
Doug Doohan theorizes that soil balancing might affect weed populations indirectly through improved soil structure and infiltration. He cautions that there is no hard data on this yet, but it’s a research question be is studying based on conversations with farmers.
What Soils Does SB Work Best On?
“I think guys that have promoted the Albrecht balance have kind of given people the idea it works in any soil and that's really not the case. And so I think some of that has drifted into the research facilities in thinking that it works in all situations and that's not the case.”
- Bill McKibben, consultant, Soil Tech, Inc. (October call-in)
Although McKibben says he grew up as an “Albrecht guy,” i.e., focused on the 65% Ca, 15% Mg base saturation recommendations, his experience has shown him this technique is much more effective on clay soils.
However, by growing and incorporating a mixed species cover crop into his soils, vegetable grower Bob Jones reports significantly increasing the CEC on his sandy loam soils. He also uses compost teas and mineral applications, rotating fields in and out of production. He feels this increase of organic matter combined with increasing his Ca:Mg ratio has led to improvements in soil and crops.
“We're raising the CEC, we're raising the organic matter levels, we're getting the calcium up in that seventy to seventy-five percent ratio with magnesium in line with that of 7:1 and that seems to be— We seem to be seeing a very marked improvement in the quality and the shelf life of the product that we're growing.”
- Bob Jones, The Chef's Garden (November call-in)
Focus on the Crop, not Just the Numbers
“The number one goal, the number one objective, needs to be to grow a really healthy crop…. So in terms of priorities sometimes the lab report might indicate that we have a soil that is severely out of alignment and we need to make major adjustments, but the budget doesn't exist and it's not possible to make that happen. In those cases, the priority always needs to be to grow a really healthy crop first and then fix the soil over time as we're able to.”
- John Kempf, consultant, Advancing EcoAgriculture (October call-in)
Other consultants chimed in, saying it’s important to get out in the field and see what’s happening. Both Kempf and McKibben recommended a Paste Analysis test to examine how nutrients are moving into the soil solution and becoming available to plants.
"I can only say what works on our farm. Going back to the question of the truth, what's the truth on your farm? Then go with that. And you can only do that by experience. My father told me a long time ago that the best fertilizer you can put on a field comes from the soles of your feet and that means walking through the field and seeing what's going on and listening to the plant. The plant’s the best test mechanism we have. Does the plant look healthy?"
- Bob Jones, The Chef's Garden (November call-in)
On-Farm Experience vs. Research
“If the universities have a different opinion than the farmers, I normally go with the farmer opinion. They may not know why something is working, but they do know that it does work. And maybe the researchers…. they may not have the whole system, where a farmer would.”
- Will Glazik, organic farmer, Cow Creek Organic Farm
Glazik spoke in detail about how he applied soil balancing on his fifth-generation family farm: how his inputs changed over time and what improvements he saw. He looks to researchers to answer questions about ‘why’ something works, which helps him replicate a practice at his own farm.
“Scientists, I think, legitimately, have a healthy skepticism about what they might consider anecdotal reports of things that people say, especially when it comes…with the sales interest in mind, and they want us to validate that. On the other hand, farmers have a very healthy skepticism and legitimate skepticism of science, and the degree to which scientists’ work is directly as applicable or useful in their work, and that's why they turn to farmers often and legitimately to get advice and counsel.”
- Doug Jackson-Smith, Ohio State, natural resources and rural sociology specialist
Doug Jackson-Smith says that if soil balancing is to move forward, farmers and scientists must work together and bring the on-farm experience to science, and science to the on-farm experience.
Why Aren’t More Universities Studying Soil Balancing?
Steve Culman said many scientists feel this topic has already been decided. But his review of published literature and farmer input, made him think there was more to study. Other panelists theorized that Soil Balancing was an unpopular topic for study because there were few products (and sales revenues) tied to it or because previous research was done on soils poorly suited for the technique.
“I think that the beauty of science is that we… claim to be a self-correcting enterprise. It might take a year or two, it might take ten years, it might take decades. We believe that truth is the foundational thing that we're after, and that, if we have it wrong now, that in time and with additional evidence, we're going to change the way we think about things.”
- Steve Culman, Ohio State, soil fertility specialist (October call-in)
"You're asking, should we be doing more research and generating more numbers. I think so in this regard, because it is a question that I get at almost every soils talk I give. Can I improve my drainage by increasing the calcium-magnesium ratio?"
- Josh McGrath, University of Kentucky (November call-in)
Join the Conversation
- Read more details about future Call-ins
- Register for December call-in.
- Read about the basics of soil balancing and Ohio State's project.
- Listen to full conversation (below).