Long term cover crop research: Maintaining and monitoring soil health

Principal Investigator: Laura L. Van Eerd

Scientific Summary:

Productive soil is critical to enhancing the long term profitability of agriculture. Cover crops may play an important role in maintaining soil health. Typically cover crop research has focused on planting the cover crop in the fall and studying effects in the following growing season. Although this approach is valid for first time cover crop users, to have meaningful effects on soil quality, long-term studies are needed. Moreover, changes to soil quality are often the result of long-term management practices (i.e. it takes a long time to detect meaningful changes in most soil quality parameters).  Therefore, to gain a true picture of the impact of cover crops on soil quality, long-term trials are needed. Permanent, long-term trials comparing various cover crops are quite rare except for two trials at Ridgetown Campus established in 2007 and 2008.

These trials are ideal for evaluating best management practices of cover cropping and potential influences on soil health. The overall goal of this research was to assess the impact of various cover crops to a no cover crop control in terms of 1) yearly and long-term (4+ year) delta yield and profit margins, 2) nitrogen dynamics, and 3) soil health. The same cover crop treatment was applied on the same plot each year and the cash crop (grain or vegetable crop) rotated yearly. The sites are on good sandy loam soil with 3.2+% organic matter. Cover crops were left to overwinter and in the following spring, the site was sprayed with glyphosate and disked/cultivated prior to planting the main crop. Over the years, the cover crops tested (forage pea, hairy vetch, oilseed radish, oat, cereal rye and rye+radish) have consistently resulted in main crop yield that was as good as or better than without a cover crop.

Unfortunately making a cover crop-specific recommendation is not simple; the cover crop that gave the highest crop yield depended on the year and the crop (sweet corn, grain corn, winter wheat, snap beans, soybeans, cucumbers, tomatoes). In soil collected in 2015 and 2016, there were measurable increases in soil health indicators (organic carbon, Cornell Soil Health Assessment, Haney soil health test) with cover crops compared to the no cover crop control. Although intuitively we know cover crops are good for the soil, it is very difficult to measure changes in soil health. Hence, it is somewhat surprising that we could detect differences after a relatively short amount of time of cover cropping (6 years). Of the cover crops tested, there was no clear ‘best’ cover crop in terms of following crop yield or soil health: therefore, farmers should grow the cover crop that matches their production system and goals (i.e., erosion control, weed fighter, compaction fighter, build organic matter, etc.).

Project Related Publications

Popular articles

Isaacs, J. 2018. Know your cover crop goals before planting. Top Crop Manager (East).  Published September 2018 issue. Interview by Julienne Isaacs. 28 Jun. 2018.  http://magazine.topcropmanager.com/display_article.php?id=3168234&view=521084

Pearce, R. 2018. Soil Health what is it and how do we achieve it? Interview by Ralph Pearce from Country Guide. 19 Jun. 2018.

Dietz, J. 2017. Cover your ground – and a lot more – between crops. Top Crop Manager. Interview with popular press writer John Dietz on 6 July 2017. Published 26 Sept.2017. https://www.topcropmanager.com/other-crops/cover-your-ground-%E2%80%93-and-a-lot-more-%E2%80%93-between-crops-20779

Nauta, J. 2017. Highlight: Cover Crop Researcher: Dr. Laura Van Eerd.  Ontario Cover Crops Strategy 2017. Developed by the Ontario Cover Crops Steering Committee. Interview by Janet Nauta. Published April 2017. https://www.ontariosoilcrop.org/wp-content/uploads/2017/06/Ontario-Cover-Crop-Strategy_May-3_Final-v3compressed.pdf

Petherick, A. 2017. What is soil health? Observations from a researcher and an agronomists Grain Farmers of Ontario Magazine. Interview with popular press writer Amy Petherick on Dec.9th  2016. Published Feb 2017. http://ontariograinfarmer.ca/2017/02/01/what-is-soil-health/

Forsythe, T. K. 2016. Investigating soil bacterial and fungal communities: Exploring the link between soil biodiversity and soil health. Top Crop Manager issue.  Popular press writer Trudy Kelly Forsythe. 9 Nov 2016. http://www.topcropmanager.com/soil/investigating-soil-bacterial-and-fungal-communities-19746#sthash.HqwogwYv.dpuf

Gilmour, G. 2016. Cover crops gain popularity.  AgriSuccess -FCC bi-monthly farm mgmt mag.  May/June 2016.  Interview and article by Gord Gilmour which features my cover crop research and KTT activities.

Sabljic, J. 2016. Understanding soil health. Research Magazine 2016 Agri-Food Yearbook Edition. Pg 28-29. Interview with SPARK program writer Joey Sabljic 11 March 2016 interview published Fall 2016 volume XXXIII.

Petherick, A. 2016. Soil Goes Under the Microscope: Researchers take aim at defining ‘soil health’. Ontario Grain Farmer Magazine. Interview with popular press writer Amy Petherick. Published February 2016. pp 2.

Scientific articles

Chahal*, I. and Van Eerd, L.L. 2018. Evaluation of commercial soil health tests using a medium-term cover crop experiment in a temperate climate. Plant and Soil. 427:351–367. https://doi.org/10.1007/s11104-018-3653-2.

Van Eerd, L.L. 2018. Autumn cover crop species and planting date on processing fresh bean and sweet corn yield and N dynamics. Nutrient Cycling in Agroecosystem 111:33-46  http://rdcu.be/HMUt

Belfry, K.D., C. Trueman, R.J. Vyn, S.A. Loewen and L.L. Van Eerd. 2017. Winter cover crops on processing tomato yield, quality, pest pressure, nitrogen availability, and profit margins. PLoS ONE 12(7): e0180500. https://doi.org/10.1371/journal. pone.0180500

Chahal I. and L. L. Van Eerd. 201x. Medium-term effect of cover crops on soil quality indicators in a temperate, humid climate. Geoderma. Re-submitted Feb 2019.

Chahal I. and L. L. Van Eerd. 201x. Cover crop and crop residue removal effects on temporal dynamics of soil carbon and nitrogen in a temperate, humid climate. Agriculture, Ecosystems and Environment. 23 OCT. 2018.

Webinars McNaughton, K.E. and Van Eerd, L.L. 2018. Cover crop best practices: what to plant and how to get rid of it. Top Crop Manager. 8 November 2018. https://www.topcropmanager.com/webinars/learn-about-terminating-cover-crops-21496/