Ohio State soil researchers Steve Culman and Christine Sprunger have analyzed soil health and management data from around 900 Ohio farm soil samples. The samples were collected during various on-farm research projects in the last few years, including about 200 from organic operations.
The Culman and Sprunger labs have looked for relationships between soil health metrics and the corresponding soil type, sampling depth, and management practices. Below are a few quick highlights and opportunities to learn more.
Management Impacts on Soil Health
The study suggests that the most effective way to increase microbial activity and other soil health indicators was to include perennials in the crop rotation, especially for multiple years.
Organic growers will be happy to hear that, so far, cover crops appear to be a better soil health building strategy than no-till. That’s not to say that tillage is good for soil health. More complex crop rotations and increased tillage showed a negative effect on organic matter and microbial activity.
Culman cautions that this is “noisy” data based on observation, not a side-by-side controlled study, nor is it a comprehensive sampling of soils. More work is definitely needed. Some of this future work will look at aggregate stability (a measure of soil physical health), compare the soil health impact from different types of tillage, and compare organic vs. conventional practices (for example, the effect of organic vs. synthetic fertilizers). The researchers are also interested in ways to decrease tillage passes in an organic system.
Emerging Tests for Soil Health
As farmers and consumers focus increasingly on soil health, there is a growing need for better soil health measurements. Data from these on-farm soil surveys is helping to further this goal as well.
Standard soil tests include a total organic content measure, but most organic matter in the soil is not available to plants. Recent research also suggests that total organic matter changes very slowly over time and is probably not the best tool if you want to track how new management practices are impacting soil health.
Ohio State’s soil labs have been evaluating soil health tests for accuracy, for their value in management decision-making, and for cost and turn-around time. The goal is to recommend useful tests to commercial labs so that these can be offered directly to farmers, along with information about state averages, ranges, and how the test values vary with soil type.
It's important that organically managed soils continue to be part of this sampling project. Ohio State will collect soil samples again in 2021 as part of eFields – an agronomic crops program to conduct and share on-farm research. Contact your local extension educator or email email@example.com for more details on getting your soil sampled for this statewide study. Individual soil test results will be shared with participating growers.
- Management Practices That Impact Soil Health and Organic Matter
March 17 Sprunger presentation (45 minutes) - part of Ohio State's 2021 Winter Organic Webinar Series
- Using Research and Data to Improve Soil Health
February 25 presentation, Steve Culman & Elizabeth Hawkins - part of Ohio State's 2021 Soil Health Webinar Series
- eFields report 2020 - see page 224 for Soil Health Survey report.
- eFields program
Learn more about the perennial grain kernza and see the trial plot in this brief video: https://youtu.be/epJaE5ihiVE (3:17)
Only a few days are left to reserve your spot at Ohio’s largest sustainable food and farming conference. Registration ends on Monday, February 8 for the Ohio Ecological Food and Farm Association’s 42nd annual conference, which will be held online February 10-15.
Among the speakers from Ohio State this year, extension soil specialist Steve Culman will be sharing information on his USDA perennial grain trials. This is Culman’s second research project on the perennial wheatgrass known as kernza. He is testing an organic variety of kernza for suitability in Ohio as a dual-purpose crop (forage and grain production). This summer his lab will begin on-farm trials and is looking for additional participants.
Kernza is used mainly for forage and grazing in the western U.S. While the grain has end uses and nutritional values similar to wheat, Culman admits the grain production is not very good and that markets and facilities for kernza are only just developing. While it has potential for dual purpose production, more research and development will be needed.
So why would a farmer consider kernza? Because it has a third purpose of great importance: Soil health.
“Organic systems go through this dichotomous cycle of growing cash crops, and then growing a crop for conservation or soil development," Culman notes. "With kernza you could do both.”
Recent Ohio State research reviewed hundreds of regional soil tests results, comparing management practices with various soil health measurements linked to yield, biological activity, and fertilizer efficiency. The most effective management practice for improving soil health was the use of perennials. Perennial crops reduce traffic and tillage, but they also leave roots in the ground year-round to contribute to biological activity, provide below-ground biomass, and crowd out weed growth. Kernza really shines in root development, with roots that reach 10 feet down or deeper and spread horizontally to outcompete weeds.
“Kernza stays pretty green through harvest,” says Culman. “It’s not like wheat. You harvest the grain in late July/early August. So you could harvest the grain, then chop or hay the remaining biomass. Then you can let it regrow. This is not enough time to develop seed heads, but the regrowth should get knee high or so in the fall. Then it can be grazed."
Based on his previous trials, Culman feels kernza has great potential for organic transition, weed control, riparian zones, forage, fall grazing, and even grain production, all while improving soil quality.
The OEFFA conference kernza presentation will be Friday, February 12 at 10 a.m., but conference attendees will also be able to watch recorded presentations through March. Dr. Culman will also be available in the OFFER virtual conference booth on Friday, February 12 from 2-3 p.m. for anyone who would like to know more about the on-farm kernza trials or to chat about soil health and fertility.
See the full line up of OFFER booth events at offer.osu.edu/booth. We will also host Glen Arnold, extension field specialist in manure management; Erin Silva from University of Wisconsin and OGRAIN; and Rich Minyo, organic corn variety trial researcher.
For more information on the OEFFA conference, visit https://conference.oeffa.org/.
To learn more about the soil health and management study findings, join us for "Management Practices That Impact Soil Health and Organic Matter with Christine Sprunger, March 17 at 11 a.m., part of the OFFER 2021 Organic Winter Webinar series.