ICYMI – Can Cover Crops Clean the Corn Belt?

There are many news headlines competing for our attention every day and while some fade into the background, water quality and conservation practices remain in the forefront as we work to meet the goals of the Iowa Nutrient Reduction Strategy.  A recent article written by Laura Sayre for New Food Economy asks the question: Can Cover Crops Clean the Corn Belt? and I strongly encourage you to check it out!

Cover crops provide a multitude of benefits including: helping improve water quality by reducing the losses of both nitrates and phosphorus, minimizing soil erosion, improving soil health and mimicking diversified crop rotation benefits by keeping the fields green in the winter.
Tobin Rye 2017

Biomass sampling cereal rye in Taylor County spring 2017

A key practice in the Iowa Nutrient Reduction Strategy toolbox, cover crops are able to help reduce both nitrogen and phosphorus leaving the field and entering water bodies.  In addition to practices like wetlands, bioreactors and nutrient management, one of the Iowa Nutrient Reduction Strategy scenarios calls for 65% of Iowa row crop acres (about 15 million acres) to be seeded with cover crops.  At just over 600,000 acres seeded in 2016, we still have a long way to go to reach that level of adoption. However, there are a variety of economic opportunities that accompany that goal including cover crop seed growers and dealers, co-op, and equipment manufacturers.

Whether or not cover crops can indeed help clean the Corn Belt is up to all Iowans.  This includes, but not limited to those mentioned in the article: researchers like Dr. Matt Liebman with Iowa State University, farmers and landowners like ILF farmer partner Tim Smith, non-profit organizations like Practical Farmers of Iowa, our state agency partners, and urban residents, like myself, all doing our part to help keep the water clean and supporting the efforts of others working towards meeting the Iowa Nutrient Reduction Strategy goals.

Liz Juchems

Do Crop Insurance Rules Put a Chill on Soil Health Practices?

An opinion piece by authors Ryan Stockwell and Jim Moseley argues that inflexible crop insurance rules are slowing the adoption of conservation practices that build soil health such as cover crops.

Practices that can improve soil health such as no-till, cover crops or multi-year crop rotations can decrease erosion, decrease nutrient loss, improve water infiltration and even provide added value in the form of fewer field passes and increased forage value for livestock. The authors argue, however, that crop insurance rules could force farmers to choose between crop insurance coverage and adopting practices that could improve their soil health:

“Yet, a significant barrier stands in the way related to crop insurance, which has become an absolute necessity in today’s weather extremes. To be eligible for crop insurance, farmers who use cover crops must meet specific management rules. No other agronomic practice includes such eligibility rules.”

While some rules have been changed in the past several years, confusion persists over rules and requirements. The article encourages policy to become more flexible by allowing local agronomic experts to guide best practices, as is the case with many other agricultural practices such as fertilizer application or weed management.

Read the article from Agri Pulse here. What do you think? Do you have a crop insurance question or story related to a soil health practice?

Julie Whitson

Cover Crops: One Piece of the Puzzle in CLL Project

Cover crops are an important tool for helping keep soil, nitrogen and phosphorus in the field – instead of our water bodies. Because they grow outside the typical corn/soybean growing season, cover crops help reduce soil erosion and take up nutrients that could otherwise leave the field. It is also the most popular practice among our Conservation Learning Lab (CLL) farmer partners.

The CLL project is studying the impact of conservation practices implementation at the watershed scale in Floyd and Story County.  The conservation planning process within the watersheds has yielded cover crop contract enrollment of 675 acres and 1,081 acres, respectively, starting this fall covering 50-68% of the crop acres within the watershed.

Cover_crop_April_Berger_FarmThe farmer partners chose to seed either winter cereal rye and oats.  These grass species are easy to establish, relatively inexpensive and are the leading biomass producers in our cover crop research projects – keeping that soil covered (reducing the loss of phosphorus) and taking up nitrogen.

The Iowa Nutrient Reduction Strategy team reviewed cover crop research results from across Iowa and the Midwest and found that cereal rye and oats reduced nitrogen loss by 31% and 29%, respectively.  Similarly, the reduction of phosphorus when adding cereal rye is about 29%, primarily as a result of reduced soil erosion. According to our RUSLE2 calculations, a cereal rye cover crop added to a no-till system can reduce soil erosion by 30-80% and can be even larger when transitioning from a conservation tillage system.

Be sure to keep checking back as we will be providing updates as the cover crops are seeded this fall!

The project is funded by the Iowa Department of Agriculture and Land Stewardship (IDALS) and the United States Department of Agriculture – Natural Resources Conservation Services (USDA-NRCS) of Iowa.

Can cereal rye cover crops suppress weeds?

A question recently arrived in my email inbox: What is the potential for weed suppression when using cereal rye cover crops?

To help answer the question, I reached out to Dr. Bob Hartzler, ISU Extension Weed Specialist and Professor of Agronomy, and Meaghan Anderson, ISU Extension Field Agronomist.


There is pretty good evidence that a thick, consistent Slide1stand of cereal rye can effectively suppress winter annual weeds.  In soybeans, rye with even cover and a lot of biomass (>4000 lb/ac) may provide some early season weed suppression, but generally the weeds will begin to emerge as the cereal rye breaks down.

Ann and I saw this first hand yesterday (photos below) when visiting our long term rye site in Page County to collection biomass samples. In the cereal rye strips only one or two field pennycress plants were found. However, in the neighboring strips without cover crops, the winter annual weed was thriving.

No evidence yet that cereal rye will help control perennial weeds, but it may help Slide2suppress perennial weeds germinating from seed or perennial rootstalks like dandelion, Canada thistle, field horsetail, etc.  Perennials normally develop from established root structures with a lot more energy reserves, so they are going to be tolerant of the competition from the cover crop.  If repeatedly used, cover crops could provide some suppression of things like dandelion and such.

Whether or not it provides some suppression or control of  resistant weeds would depend on whether those weeds fall into the categories listed above (early-season weeds or winter annuals) and whether the cover crop stand is consistent.

To keep up to date on weed issues, follow Dr. Hartzler on Twitter @ISUWeeds!

Liz Juchems

Now Available! Evaluating Cover Crop Seeding Techniques Publication

Seeding Tech LocationsThe Iowa Cover Crop Working Group (ICCWG) has wrapped up a two-year study evaluating planting techniques for the successful establishment of cover crop mixtures and single species in Iowa. We are grateful to our partners: Hagie Manufacturing Company, famer partner Tim Smith, and Iowa State University Northern Research and Demonstration Farm.

Replicated cover crop strips were established in fall of 2014 and 2015 to compare three different seeding techniques:

Evaluation was completed through fall and spring biomass collection and crop yield. A no cover crop plot was included in the replications as a yield comparison check strip.

The mixtures species were selected based on the upcoming crop and their winter hardiness. Because the species seeds are different sizes, a goal of one million seeds per acre was used for seeding calibration to provide a fair comparison between treatments.

Seeding Mixtures

Oats and rye win the day

Results show that earlier seeding with the high clearance interseeder resulted in more cover crop biomass, both fall and spring, than the later seeding with a drill. For Iowa, oats and rye work better than any other species tested at this time. The single species (oats and rye) resulted in more total biomass than the mixtures providing better soil erosion protection. Oats and rye were also the predominant species in the mixtures, accounting for the majority of the biomass.

Seeding Tech Biomass

There are no statistical differences in corn or soybean yields across the different cover crop treatments and no cover check plots. This yield neutral response following a cover crop is consistent with a long term ICCWG cereal rye cover crop project now entering its ninth year.

The publication is now available online and at upcoming ILF field days.

This research project was made possible with a State Conservation Innovation Grant through the Iowa Natural Resource Conservation Service.

The ICCWG includes core members from: Iowa Learning Farms, Practical Farmers of Iowa, Iowa State University Extension and Outreach, USDA-Agricultural Research Service, Leopold Center for Sustainable Agriculture, Iowa Department of Agriculture and Land Stewardship.

Can Healthy Soil Feed the World?

A recent article written by David Montgomery, Professor of Earth and Space Sciences at University of Washington, shares a provocative argument for why healthy soil is the real key to feeding the world. The article is a quick read, and it provides good food for thought to break through the Monday shuffle.

Soil1

Montgomery recently wrote a book called, “Growing a Revolution: Bringing Our Soil Back to Life” where he traveled the world to interview innovative farmers. These
farmers had one thing in common: they were rebuilding the health of their soil with regenerative practices like no-till, cover crops and diverse crop rotations that brought in high yields while also increasing soil fertility. Seeing the potential in these varied practices, Montgomery wondered if these practices could change the very foundation of agriculture as we know it, both in the Corn Belt and beyond.

“Their experiences, and the results that I saw on their farms in North and South Dakota, Ohio, Pennsylvania, Ghana and Costa Rica, offer compelling evidence that the key to sustaining highly productive agriculture lies in rebuilding healthy, fertile soil. This journey also led me to question three pillars of conventional wisdom about today’s industrialized agrochemical agriculture: that it feeds the world, is a more efficient way to produce food and will be necessary to feed the future.”

Soil2

2013 Iowa Learning Farms Field Day at the Kent Swanson farm in rural Red Oak

Beyond conventional versus organic, Montgomery posits that our future, and the future of our soil, relies on innovative farmers who are willing to adopt practices that put soil health and prolonged soil fertility first.

Read the article, “Healthy Soil is the Real Key to Feeding the World” and tell us what you think.

Julie Whitson

Recent Article Looks at Soil Health from a Global Perspective

A recent article from Environmental Health News titled, “Is soil the great new integrator?” explores what farmers around the world are doing to counter threats to soil quality in an era where all farmers are facing global pressures to push soil to the max. Soil has different properties and challenges in different regions of the world. From Valle del Cauca in Colombia, to northern Punjab, India, to many areas in the United States, farmers are learning how to work with the soil they have and improve soil health to protect themselves from erosion, drought and extreme weather events.

The author, Lisa Palmer, says that farmers are “bucking the trend” and beginning to consider soil health as a business decision.

“Molina and other farmers I’ve met with over the years are bucking the trend. Their attention to soil has been a business decision, leading to increased production and yields, and has helped them withstand weather extremes.

It’s catching on: In a recent survey, insight from 2,020 farmers from across the United States reflected enthusiasm for cover crops to help improve soils—for the fourth year in a row—and found a yield boost in corn and soybeans following cover crops.”

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Cereal rye cover crops start to green up in Spring 2017 near Nashua, Iowa

Not only is building soil a business decision, but it can also help farmers insulate themselves from extreme conditions like drought, windstorms and heavy rain events.

Read the article to learn more about what farmers are doing in different corners of the world to make soil health work for them.

Julie Whitson