Cover Crops Critical to Erosion Control in Missouri

Tim Gottman on the farm he runs with his brother, Trent, in Missouri.

Business Case: TJT Gottman Inc.

Farmer Profile

  • Farm owned by brothers Tim and Trent Gottman

  • Working with SHP since 2017

  • Experimenting with cover crops on SHP trial field

  • Partnering with Missouri Corn, Missouri Soy and Missouri Dept. of Natural Resources on their Edge of Field Water Quality Monitoring Program

  • Farms in Marion and Shelby Counties

  • Planting corn-soybean-wheat rotations

For Tim and Trent Gottman, building soil health through reduced tillage and cover crops is critical to reducing erosion on their Missouri farm. By keeping the soil in place, they hold onto valuable nutrients and help protect nearby waterways.


Tim Gottman farms near Monroe City, Missouri. Along with his brother, Trent, they own and operate TJT Gottman, Inc., growing corn, soybeans and wheat. While Tim remembers the days of farming with his dad and grandpa with a moldboard plow, he knows the productivity and longevity of his farm depend on continuing to evolve his approach.

Today, Tim and Trent leverage vertical tillage and cover crops to reduce erosion, maintain nutrients, and protect water quality. Through collaboration with Soil Health Partnership (SHP), Missouri Corn Merchandising Council, Missouri Soybean Merchandising Council and the Missouri Department of Natural Resources, they are studying the impacts of these management practices – both on their farm and on the surrounding environment.

Success starts with clear goals

It was in the mid-2000s when Tim says he first started noticing a significant change in weather patterns. Rainfall events seemed more frequent and more extreme in the spring, pushing planting dates back later and later. Over years of watching his soils wash away, he and his brother worked toward strategically approaching erosion control in a way that was financially feasible for their farm.

“I don’t want to be the guy that stands in the shop every time we get a big rain and go, ‘Well…’ and just shrug my shoulders,” Tim said. “It seemed to me we needed to start adopting practices where, when that happens, you haven’t lost all your fertility, you haven’t lost all your soil – you stand to live another day. We had to do something to slow this water from running off.”

So, in 2014, they invested in a Salford® vertical tillage tool and began using cover crops. Along the way, every decision he and his brother made was driven by a singular vision.

“Our goals [with soil health] have always been around reducing erosion. And we believe that, as the soil structure improves, the price tag will be worth it.”

Tim’s approach to erosion control

Tim plants cover crops on 60% of his acres, primarily using cereal rye – because of how well it overwinters and its hardiness – but he also mixes in radishes, turnips and oats on fields with wheat stubble.

On his SHP trial field, he is comparing cover cropped strips to strips with no cover crops. The first couple of years he broadcast applied cover crop seed, similar to what he does on his non-SHP fields. However, in 2018, he chose to start using a drill for cover crop application (the same one he uses to plant wheat). Thanks to better seed-to-soil contact, the drill has helped provide more consistent stands.

Tim Gottman’s Annual Soil Health Approach

When using a cover crop and/or no-till system, management decisions need to be adjusted based on field conditions and weather. Creating a yearly plan can help to identify cost savings, opportunities for maximizing soil health benefits and alternative approaches for unknown circumstances.

The timeline below overviews Tim’s planning process, starting in late summer when cover crop decisions are initiated.

Late Summer

After Corn Harvest

Spring Ahead of Soybeans

  • Starts having conversations with local ag retailer in late July/early August for cover crop orders

  • Plans cover crop selection based on current crop rotation, estimated harvest dates and field needs

  • Begins strategically planning each field’s estimated cover crop application schedule

  • Contacts ag retailer to have cover crop seed broadcast applied with P&K application
    for fields going to soybeans
    or wheat

  • Targets broadcasted cereal rye rates at 40 lbs. per acre

  • Initiates pre-plant chemical termination (April/early May), when cover crop growth is still manageable – targets the vegetative growth stage between 2-3 feet

  • Makes one spring vertical tillage pass, depending on soil moisture and weather conditions (cover crops are dead and turning yellow at this time)


Overall Fertilizer Program

Tim applies lime, P and K as needed for all fields, determined using a three-year grid soil sampling program. In corn, he also uses a split-applied nitrogen program to help optimize both nitrogen rate and timing. This includes applying anhydrous in the spring and top-dressing urea in-season.

Soil health is a learning process

For Tim’s timeline, challenges arise when it comes to time and labor. To cover multiple fields during the harvest season, having a local cooperative or ag retailer broadcast the field with dry fertilizer is ideal.

Another challenge has been finding a cover crop system that works before corn. In general, soybeans are harvested in October so finding an overwintering cover crop that gets well-established before the weather turns, provides erosion control and creates diversity can be difficult. Cereal rye before corn can come with its own set of obstacles and finding winter hardy brassicas and legumes has been a challenge, so Tim is looking into other grasses like barley. Tim continues to trial different species, applications and ideas to find what will work best.

Note: If you are considering planting a grass cover crop before corn, up-front nitrogen is important. Consult with your advisor for best practices when using overwintering grasses before corn.

“Any time we can show that farmers are trying to be stewards of the land and doing what we can to keep these nutrients from running off, then we can have a positive voice.”

Soil health efforts are making an impact on erosion & fertility

Through the Missouri Edge of Field Water Quality Monitoring Program, Tim is measuring soil loss on a field with cover crops and one without (these trial fields are located near his SHP field). During the last several years, he has been able to see how much soil he is saving on the cover cropped field, as compared to the one without (Figure 1), which has been about 28 tons (or two tandem dump truck loads) per acre over the last three-and-a-half years.1

That said, Tim notes that he doesn’t necessarily need the numbers to know his efforts have been beneficial.

“We’re not seeing near as much sheet erosion as we have in the past, where you would see our grass waterways just fill up with top soil.”

By looking at data from both SHP’s research and the edge-of-field study, we can see that soil structure plays a big role in keeping that soil in place. One way to evaluate soil structure is by testing for aggregate stability, which measures how well the soil holds together during rain events and is known to contribute to improved moisture infiltration. Tim has seen a significant increase in aggregate stability on his SHP trial field in the cover cropped strips (Figure 2).

Measuring soil loss via suspended solids

Evaluating changes in aggregate stability


Figure 1. Soil loss 2017-2020 between cover cropped and non-cover cropped trial fields in the Missouri Edge of Field Water Quality Monitoring Program

Figure 2: Changes in aggregate stability on Tim Gottman’s SHP trial field

Along with these benefits, Tim has seen no significant yield drag and relatively little change in net income. He said, “I think people look at the cash cost of [cover crops], but if you can save 5-10% in fertilizer per year and it stays in the soil instead of running off through erosion – I don’t have to do the math; that’s money ahead.”

1 It is important to note that, while cover crops have helped reduce erosion on that field, the non-cover cropped field has additional characteristics (e.g., topography) that made it especially susceptible to erosion – making the differences between the two fields particularly stark.

Research tells the story of agricultural sustainability

As an active member of the Missouri agriculture community, Tim knows the value of data collection in conversations around sustainability. That’s one of the big reasons he got involved in these studies. In addition to talking with his neighbors and land owners about the steps he’s taking to build soil health and reduce erosion, he believes that hard numbers help farmers advocate for themselves with elected officials.

“Any time we can show that farmers are trying to be stewards of the land and doing what we can to keep these nutrients from running off, then we can have a positive voice.”

You can find a print version of this business case by clicking the button below.

Nutrient Management

Nutrient management involves determining the appropriate rates, timing, source and methods of fertilizer application for crop nutrition. Taking into account the science of soil, crop, weather and hydrologic factors, nutrient management also aims to reduce nutrient loss from the field to improve profitability for the farmer, and water quality for society.

4Rs of Nutrient Stewardship

Right Source

Matching the right fertilizer for your crops’ needs

Right Rate

Matching the right amount of fertilizer for your crops’ needs

Right Time

Making the fertilizer available when needed by the crop

Right Place

Applying the fertilizer where it is available for the crop and less prone to loss

Factors that affect nutrient management

Soil Fertility

Use results from a soil lab to determine the current available amounts of nutrients in the soil and actively manage soil pH. Availability of certain nutrients or chemicals in the soil can impact the availability of other nutrients. Using the same lab and the same sampling points every time you test is important. Variations in test methods can affect recommendations.

Soil Texture

How fine- or coarse-textured soil is can impact how readily a soil can retain or lose nutrients.


Soil fertility and fertilizer needs vary by crop.


Temperature and moisture can have large impacts on both the loss of nutrients from the soil and the availability of nutrients to a crop.


Fertilizer options can vary by region, cost, and available application equipment.


Available equipment can impact the best source, rates, placement, and timing for a fertilizer.

Geographic Recommendations

Many state Extension services provide local and regional recommendations for fertilizers. Some agronomists may offer recommendations based on local on-farm research.

Use results from a soil lab to determine the current available amounts of nutrients in the soil and actively manage soil pH. Availability of certain nutrients or chemicals in the soil can impact the availability of other nutrients. Using the same lab and the same sampling points every time you test is important. Variations in test methods can affect recommendations.

Additional considerations


Local and state regulations may dictate the timing, source, rate, and placement of fertilizers. Reference the state-specific NRCS standard for nutrient management (590 Nutrient Management).

Precision Agriculture (Variable Rate Technology)

Precision agriculture, or variable rate technology, provides the opportunity to manage nutrients differently for every acre. For example, it may make sense to shift fertilizer from areas that have high fertility or high risk of nutrient loss to those with low fertility and low risk of nutrient loss allowing for greater return on investment with fertilizer.

Nutrient Management Plans

Certain geographies and livestock operations are required to establish Nutrient Management Plans which may have further restrictions on fertilizer or manure applications. Sometimes these are not required but are incentivized. They must be written by a Certified Crop Advisor registered within your state who is also a Technical Service Provider with the USDA’s Natural Resources Conservation Service.

A grower can formulate their own Nutrient Management Plan to be organized and ready to work with their supplier. This allows the option to customize it to your operation with the option to change it as necessary. Set attainable economically minded goals for raising soil fertility in low testing fields as well as plan which fields would have the most advantage of higher fertilizer applications and which have lower requirements.

Additional nutrient management resources

Click on thumbnail or title to download pdf.

You can find a print version of this informational resource by clicking the button below.

Find Out More

Learn more about nutrient management by checking out recent Soil Sessions webinar on the topic.

Farmer Experiences Highlight the Intersection of Nutrient Management and Soil Health

When getting started with new conservation and sustainability practices, it can be challenging to know where to start. Should I look at tillage or cover crops first? Does it make the most sense to adapt my nutrient management approach or change how I soil test? When you find yourself asking these questions, one of the best first steps is to explore what others have done and consider how their learnings can be leveraged on your farm.

On our most recent Soil Sessions webinar, we focused on farmer experiences and case studies that can help you better understand different approaches and their impact. In this session, Dr. Sally Flis of The Fertilizer Institute shared findings from their case studies (specifically around implementation of 4R practices for nutrient management) and Lisa Kubik from Soil Health Partnership shared key takeaways from a recent SHP business case featuring Roger and Wesley Zylstra in Iowa.

Finding the approach that works for you takes time

It can be easy to want a quick fix for building soil health or adapting nutrient management strategies, and yet Lisa and Sally both emphasized how their farmers have had to dial in their approach over time.

At Cox Land and Cattle Co. – a 4R Advocate farm in Illinois – Sally shared how Maria Cox and her family have been experimenting with different approaches to tillage, cover crops, sampling techniques, variable rate and split fertilizer application, and conservation practices (buffer strips, grassed waterways, CRP) to find a system that works for them.

Similarly, Lisa shared how the Zylstras have adapted several management practices since the beginning of their SHP trial work. These changes range from adjustments in fertilizer type and timing to cover crop seeding rate and application. Each change was made with the farm’s equipment, labor and schedule needs in mind.

Things to consider when choosing a system that fits your farm include:

  • Soil characteristics
  • The specifics of your site
  • Crop yield and quality goals
  • Manure management
  • Weather
  • Cost

Sustainability and stewardship must be balanced with profitability and productivity

Whether farmers were featured in nutrient management or soil health case studies, they all expressed a desire to run sustainable farms and be good stewards of their resources. With that in mind, though, they all recognized the importance of balancing that desire with the reality of paying attention to profitability and productivity.

This focus on cost, according to Sally, was one of the driving factors behind The Fertilizer Institute (TFI) creating a series of case studies. In these farm experiences, TFI and their partners looked at the economics of shifting from basic nutrient management practices to advanced practices. In one example, featuring an Illinois corn farmer, the grower saw a decrease in cost of $15-24 per acre as they moved from basic to advanced practices. This savings was driven by improvements in nutrient use efficiency, nitrogen balance and CO2 emissions.

In the Zylstra business case, Lisa highlighted how the farm has seen an improvement in yield, despite applying the same amount of nitrogen as in years past. She says Roger Zylstra credits this improvement to changes in application timing, type, and method, which allows him to put nutrients where the crops need it at the right time in the season for best utilization.

What both presenters emphasized is that it doesn’t have to be an either/or approach. Their case studies reveal that improvements in management practices driven by a desire to be more sustainable can also have a positive economic impact.

Digging In

These takeaways are only the tip of the iceberg of Sally’s and Lisa’s presentation and their observations from on-farm research. To learn even more about their work and what farmers are learning at the intersection of nutrient management, soil health and conservation practices, check out the full Soil Sessions webinar.

17. Ben Gleason – Soil Health Awareness is ‘Mission Accomplished’ at IA Corn

Iowa Corn has several major goals that drive programs and projects for their sustainability platform:

  1. Protect and improve the land, water, and natural resources
  2. Minimize regulations on farmers that could potentially reduce profitability
  3. Maintain farmers’ social license to operate
  4. Be a leader in sustainability, making sure that sustainability is a part of all programming

Ben Gleason, Sustainable Program Manager for Iowa Corn, gets the opportunity to work for Iowa farmers on all of these goals, leveraging partnerships with different stakeholders to move the needle on sustainability in the agriculture industry.

One area he is focusing on is reduced tillage. Tillage changes are one opportunity for farmers to impact on-farm sustainability and have become more prominent as awareness increases. Gleason says the state isn’t all no-till by any means, but is seeing strip-till gain in popularity as it is often “the best of both worlds” – tillage where you need it and residue everywhere you don’t.

Regarding cover crops, Gleason said, “We have seen a big, big jump in cover crops, which is fantastic. We went from virtually zero acres to about two million acres. I think we’ll be well over that this year with an early harvest that will allow more cover crop acres to get seeded.”

Iowa farmers are also experimenting with other practices, like nutrient reduction wetlands, which Gleason says are effective to manage nitrogen loss.

“We’re making progress. We have got a long way to go. Obviously, our water quality issues didn’t pop up overnight, so we’re not planning to solve them overnight either. But we have got a lot of momentum going, and we would like to keep it that way,” he said.

Iowa Corn also has a history of connecting Iowa farmers with the Soil Health Partnership, with both organizations really stressing farmer-to-farmer, peer-to-peer learning. They believe that works best.

“Soil health awareness is huge now. I think that mission is accomplished. [Soil health is] part of the decision-making process now, I believe,” he said.

Learn more about Iowa Corn’s specific water quality and sustainability programming, as well as how they are facilitating farmer-to-farmer learning during a global pandemic, by clicking on the player above or listening to The People of Soil Health in your favorite podcast player.

Livestock Manure’s Role in Soil Health

Livestock manure is known to provide valuable nutrients to the soil. And, if managed correctly, it can also provide additional benefits by improving the soil’s biological, chemical and physical properties.

How livestock manure affects soil health

Manure is composed of four main components: carbon, nutrients, microbial life, and water.

Livestock manure is mainly composed of carbon compounds that have been broken down by the animals’ digestive tracts. Carbon that is incorporated into the soil profile improves many soil health indicators, such as water holding capacity, nutrient cycling, and raising and/or buffering soil pH. 

While many plants and animals can survive at different ranges of pH, it is still important to maintain soil pH values between 6-8 so that soil nutrients are available. Manure has been found to have a liming and buffering effect, which can benefit crops growing in acidic soils.

Manure in the soil also increases the cation exchange capacity, which affects soil’s ability to hold onto available nutrients. Increasing soil carbon through manure adds available sites in the soil where nutrients can bind and be made available to crops throughout the growing season. This increases nutrients in the soil; though, it’s important to note, not all nutrients found in manure are immediately available and some may need to be broken down by microbes or chemical transformation in order to be taken up by plants. 

Most importantly, manure is an important part of recycling nutrients. Livestock that eat and digest the grain or leaf tissues are removing nutrients from the soil. When that manure is applied to the soil, many of those nutrients are returned. This increases soil biological activity by introducing new and important microorganisms from manure, as well as animal saliva while the animal is grazing. Nutrients from manure (when applied correctly) can also mean growers are spending less money on commercial fertilizers.

How to assess the value of manure to your soil

  • Get your manure tested. Nutrient values differ between species, as well as where it’s pulled from in the lagoon or pile. Most universities or state organizations have manure recommendations for this information.
  • Estimate the cost of commercial fertilizer and compare it to the amount of micro- and macronutrients you applied to your soils. Remember, most manure nutrients are not immediately available in the first year and so it will benefit you for up to two years after application!
  • Calculate rates of removal from row crops to know how much manure you need to apply, as well as to know whether you are applying for N or P needs (this is state-specific). Always follow state and local legislation around manure management.
  • Avoid high-risk areas that may impact groundwater or wetlands. We want to improve soil health, but not at the cost of harming other systems. 
  • Incorporation of manure prevents N volatilization (gaseous losses), which gives you more N available for crops but can impact soil aggregation. There is new and existing research looking at what is the best method of application for manure – whether injected, incorporated, or broadcasted – so be sure to do your homework and consider your farm’s available resources (e.g., equipment) to determine the best approach.

Cover Crop Lessons from an Iowa Farmer: Take Your Time

When Roger Zylstra and his son Wesley started experimenting with cover crops on their central Iowa farm in 2014, they weren’t exactly sure what to expect. They had a goal to improve stewardship of their land and resources but, at the time, didn’t really know where that would take them. Their experiment – cereal rye before soybeans – seemed to be yielding benefits, but they wanted more hard data. So, in 2015, Roger enrolled in an SHP cover crop trial to better understand the impact of this management practice on their farming operation.

Roger and Wesley’s experience with SHP is detailed in a new business case, sharing where they started and what they have learned after conducting their trial for five years. Below are some of the Zylstras’ key learnings. Dig into the full business case to find out more.

Build soil health in a way that works for your farm

In addition to growing corn and soybeans, they also raise hogs on the Zylstra farm. The incorporation of livestock makes manure an important source of nutrients for their cash crops, and it was something Roger and Wesley considered when choosing to implement cover crops.

“We’re working to continue to be competitive with our yields, while striving to improve the health of our soil,” Roger said. “Because we have swine and fall-apply the manure, we think cover crops really help sequester the nitrogen to the soil.”

They chose cereal rye as their cover crop species specifically because of its ability to withstand disturbance caused by injecting manure, recognizing that it bounces back quickly with minimal impact to the stand. Cereal rye also overwinters well, which provides ground coverage and nutrient uptake throughout the fall and spring.

It is okay to make changes over time

Roger knows how easy it can be to want to make all the changes at once, but his experience with SHP taught him that it can be valuable to make incremental shifts – evaluating your results and then adapting accordingly.

Here are just a few of the things that have changed in the Zylstras’ approach since 2015:

  • Eliminated use of fall anhydrous and incorporated spring pre-plant and sidedress applications
  • Adjusted cover crop seeding rates
  • Experimented with different methods of cover crop seeding (switching to drilling for a few years before returning to spreading/incorporation with vertical tillage)
  • Moved to 100% liquid application of fertilizer
  • Experimented with planting green

Each of these adjustments from year-to-year allowed them to dial in their system in a way that best met their unique needs around labor, time, and equipment resources. You can read more about the specific reasons for these changes in their business case.

Small changes add up to real benefits

By staying committed to building soil health, making incremental changes, and experimenting with different approaches, the Zylstras have seen real benefits to their farming operation. Some of the biggest takeaways include: 

  • Improved nutrient use efficiency – By changing the sources and timing of nitrogen application, they see greater utilization by the crop and reduced leaching of nutrients into the waterways. According to Roger, “We use about the same amount of nitrogen per acre as we did many years ago, but our average [corn] yields have grown from 140-170 bu/acre to 170-200 bu/acre.
  • Increased microbial activity – Results from soil health testing on their SHP field shows that respiration (an indicator of microbial activity) has increased significantly on the cover cropped portion of the field, aiding in an improved rate of residue turnover on those acres.
  • Improved soil structure – The Zylstras credit improvements in soil structure with reducing soil surface compaction during the wet years of 2018 and 2019. In comparison to nearby farms (who faced standing water and ruts in the field), Roger and Wesley experienced fewer equipment tracks and less ponding. At times, it has also allowed them to get into the field a day or two earlier during planting and harvest. 

Digging In

When it comes to building soil health, no two farms are exactly the same. However, there are things we can learn from each other as we experiment, adapt, and experience success. Farmers who leverage manure as a primary source of nutrients can see from the Zylstras’ SHP program one way to implement cover crops and things to take into consideration when getting started. And, no matter what your system looks like, Roger’s advice to take it day-by-day and season-by-season – adjusting your practices over time to find the approach that works best for you and your farm – is something we can all learn from.

Cover Crops and Nutrient Strategy in Iowa

Roger Zylstra and his son, Wesley Zylstra, on their Central Iowa farm

Business Case: Roger and Wesley Zylstra

Farmer Profile

  • Working with SHP since 2015
  • Experimenting with cover crops on their SHP research field
  • Total farmed area is 700 acres
  • Planting corn-soybean or corn-corn rotations
  • Using swine manure and spring/in-season nitrogen applications

Seven years ago, Roger and Wesley Zylstra set out to improve stewardship of their land. By paying attention to their nutrient management and incorporating cover crops, they started down the path of adapting their management system to meet soil health, yield and economic goals.


The Zylstras farm 700 acres in Central Iowa on primarily silt loam soils. They grow corn and soybeans, and their land is typically in a corn-soybean or corn-corn rotation. Roger and Wes also raise hogs on the farm, and swine manure provides an important source of nutrients for their cash crops.

When they started down the path of improving stewardship in 2014, the Zylstras were relying on fall-applied manure and anhydrous to meet the needs of the growing cash crop in the spring. They were interested in trying cover crops, but knew they would need to consider changing the source and timing of their nutrient applications if they were going to adapt their management system. Average farm-level corn yields in 2014 were around 170-190 bu/acre.

Crop management changes on the Zylstra farm

Cover crop trials began
  • The Zylstras used manure application and fall anhydrous until 2014.
  • On their own, they tested 12 acres of cover crops in 2014.
Cover crops on all soybean acres 
  • The Zylstras joined SHP to trial cover crops on one field in 2015.
  • They planted cover crops on all soybean acres using a broadcast spreader and incorporated cover crop seed with vertical tillage.


First year drilling cover crops
  • In 2016, they drilled cover crops to get better seed-to-soil contact and moisture availability.
  • The Zylstras timed nutrient application to meet cash crop needs with pre-plant and sidedress nitrogen (eliminated fall anhydrous).
Dialed in their system
  • The Zylstras adjusted cover crop seeding rates and methods in 2017.
  • During this season, they planted 70-90% of their acres to cover crops.
Determined best practices for their farm
  • In 2019, the Zylstras added liquid P and K to the planter & added zinc to their starter to further support yields.
  • They returned to broadcast-seeding cover crops and incorporating with vertical tillage, due to maintenance and time constraints.
Advanced soil health practices
  • In 2020, the Zylstras met their goal of eliminating dry fertilizer.
  • Due to weather, they attempted planting soybeans green into 2-foot-tall cereal rye with beneficial results (more on this below).

Choosing the right cover crop

In 2014, the Zylstras planted their first 12 acres of cover crops to cereal rye before soybeans.

To better measure the impact of cover crops on one of their fields, the Zylstras joined the Soil Health Partnership in 2015. They quickly transitioned to planting cover crops on all soybean acres in 2015. To start, they seeded cereal rye at 60 lbs/acre with a spreader and used a vertical tillage tool to incorporate the seed.

The Zylstras chose cereal rye because they were looking for a cover crop that withstood the disturbance caused by injecting manure; they found that cereal rye bounces back quickly in this situation and the stand was minimally affected. And, since cereal rye overwinters, it provides ground coverage and nutrient uptake throughout the fall and into the spring.

Roger Zylstra and son Wesley inspecting a no-till drill on their Central Iowa farm
Roger Zylstra and son Wesley inspecting a no-till drill on their Central Iowa farm

Adapting cover crop and nutrient management practices

Between 2016-2018, the Zylstras made a number of management changes in order to dial-in their system.

Eliminated use of fall anhydrous and incorporated spring pre-plant and sidedress applications.

These changes made nitrogen available to the corn plant in the spring – during the period of rye stover breakdown – and also timed nitrogen availability throughout the season for optimal cash crop uptake and minimal loss to the environment. Although injected nitrogen was their end goal, they used dry fertilizer spread on the soil surface during the transition.

Adjusted cover crop seeding rate.

In order to reduce the amount of biomass produced (and associated potential issues in establishing the next cash crop), as well as to lower overall cover crop seed cost, the Zylstras lowered seeding rates for cereal rye to 25-35 lbs/acre.

Experimented with different methods of seeding cover crops.

Beginning in 2016, Roger and Wes experimented with drilling their cover crop in order to get better seed-to-soil contact and to improve moisture availability. They liked the benefits of drilling; however, by 2019, they had decided to return to spreading and incorporating cover crop seed with vertical tillage. Using a spreader and vertical tillage, they lowered their equipment maintenance costs and were able to seed more acres in less time.

Advanced cover crop and nutrient management practices

Since 2019, Roger and Wes are taking even more steps to achieve their management goals – including experimenting with new cover crop management practices and advancing nutrient management on their operation.

100% liquid application of fertilizer.

In 2019, the Zylstras added liquid application equipment to the planter to allow for banded application of P and K on both sides of each planter row (1 in. over and 3 in. down), along with in-furrow, low-salt starter and extra liquid nitrogen (if no manure was applied).

Experimenting with “planting green”

The Zylstras typically terminate their cover crop early to minimize the chance of cover crops interfering with the establishment of the cash crop. This usually also allows them to plant sooner. However, in 2020, there was a field they were unable to spray on time, due to unfavorable weather conditions. As a result, they planted soybeans “green” – or directly into the still-growing cover crop. Roger felt they experienced slightly better weed control on that field, while also benefiting from more spring cover crop growth and more desirable timing in terms of when they could get in the field. With that in mind, the Zylstras are considering experimenting with planting green on more acres in the future.

“We use about the same amount of nitrogen per acre as we did many years ago, but our average [corn] yields have grown from 140-170 bu/acre to 170-200 bu/acre.” – Roger Zylstra


Respiration (in mg CO2/g dry weight) – an indicator of microbial activity – increased significantly on the cover cropped portion of the field, as noted in the chart above.

Add up the small changes and they bring real benefits

The Zylstras changed their management system by making incremental changes and experimenting over a number of years. What benefits do they see?

Same amount of nitrogen, higher yields.

The primary benefit that Roger and Wes see is the ability to improve nutrient use efficiency by changing sources and timing of application. While a liquid fertilizer program does cost more per unit, the nutrients are able to be used more efficiently by the crop. “In corn years, we allow the corn to utilize more of the nutrients,” Roger says. “And we are able to prevent nitrogen from leaching into our creeks and streams.”

Soil health testing suggests cover crops have increased microbial activity.

Results from soil health testing on the Zylstra’s Soil Health Partnership field show that respiration – an indicator of microbial activity – has increased significantly on the cover cropped portion of the field. One tangible benefit of this increased microbial activity at the farm scale has been an increased rate of residue turnover on acres with cover crops.

Improved soil structure.

The Zylstras credit improvements in soil structure with reducing soil surface compaction during the wet years of 2018 and 2019. In comparison to other farms in their area that created ruts in their field and had water standing after large rainfall events, they see fewer equipment tracks and less ponding. These improvements in soil structure also reduce the potential for erosion during times of maximum disturbance.

Brian Martin

Brian Martin farms 35 percent of Martin Row Crops in Centralia, Missouri.  He is a fifth-generation farmer on a family farm that once focused on diversified crops and livestock, but now features row crops and a cow-calf operation.  Brian entered the partnership in 2003 while still in high school and continues to grow his part of the farm while also providing independent crop consulting services for other farmers.

Brian has 80 acres dedicated to the Soil Health Partnership practices, including no-till corn and soybeans, cover crops like radishes, turnips, rye, wheat, and barley, and a nutrient management plan based on 2.5 acre grids from which soil samples help him determine how to split-apply nitrogen.

“I joined the Soil Health Partnership in 2017 because of my interest and passion for soil conservation and so that we can show that these management practices have a long-term economic benefit to our industry and future generations,” Brian said.

As much as anything, Brian has benefitted by learning from other farmers also in the partnership, best practices and sharing of ideas. He says that some of these practices have improved water infiltration rates and soil porosity on his farm. However, many of the metrics measuring improvement can take many years to change. It is a long-term process.

“Ultimately, I believe it is very important that we share what we’re doing with end-users and consumers as often as possible,” Brian said, “and that we are ever striving to become more efficient and environmentally conservative, as well as sustainable.”