Cover crops, no-till, perennials: How they compared on soil health impact
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