The Practical Blog

Practical Farmers' blog is a place where staff share news, updates, photos, reflections and other musings on our work and members in a more informal setting.

Cover crops are typically either aerially seeded into standing crops around the time of physiological maturity in late summer or drilled immediately following crop harvest in the fall. However, on occasion time does not permit one to get a cover crop seeded in the fall or the cover crop fails to establish.

In 2017, farmer-researchers Jeremy Gustafson and Chris Teachout evaluated spring cover crops that were seeded in March approximately 50 days before planting soybeans later in the spring.

Read the full report here: Spring-Seeded Cover Crops Ahead of Soybeans.

spring-seeded covers cover shot

How Was the Trial Conducted?

Jeremy Gustafson conducted a trial in one field where he seeded oats. Chris Teachout conducted trials in two separate fields where he seeded two different cover crop mixes. See the table below for cover crop and soybean management at the two farms.

spring-seeded covers mgmt


Aboveground biomass of the cover crop mixes was sampled the day before termination on May 27 at Gustafson’s and amounted to 1,537 lb/ac. Teachout did not collect biomass samples but reported that the mix in Field 1 was 6-10 in. tall at termination on May 19 and the oats+barley in Field 2 was 8-10 in. tall at termination on May 19. He also noted far less weed growth in the cover crop strips compared to the no-cover strips in both fields (weed biomass or weed counts were not collected, though).

Soybean yields at Gustafson’s (one field) and Teachout’s (two fields) are shown in the table below. In all three fields, the spring-seeded cover crop had no affect on soybean yield compared to no-cover crop.

spring-seeded covers soy yields

Because they saw no reduction in yield, both farmers are considering using this practice in the future. “I will use this practice [in the future] in the case of no fall seeded cover crops,” Teachout said. “The next steps are to see if spring-seeded covers can be grown with early planted soybeans as a beneficial nurse crop.”

For more details on this trial, read the full report here: Spring-Seeded Cover Crops Ahead of Soybeans.

This project was supported by the Walton Family Foundation.

For more information about this study and other studies as part of PFI’s Cooperators’ Program, contact Stefan Gailans at [email protected]

Are you growing rye or winter wheat for grain or seed this year? What’s the plan after your harvest? If you’re looking to add nitrogen for a 2019 corn crop, now might be the time to think about frost seeding red clover into that rye or wheat in late February.

Red clover as a green manure cover crop, underseeded with oats, at Ash Grove Farm in north-central Iowa in October of 2016.

Red clover as a green manure cover crop, underseeded with oats, at Ash Grove Farm in north-central Iowa in October of 2016.

The research is clear: if you can find a market for small grains, adding a third crop to your rotation yields economic, agronomic and environmental benefits. Iowa State University and Dr. Matt Liebman’s research near Boone shows that corn and especially soybeans yield better when grown in rotation, soybeans have less incidences of disease, soil health metrics improve, erosion decreases and water quality improves – all this with equal returns to land and management.

You can learn more about Matt Liebman’s research and many of the benefits of small grains production from other farmers in this video from our Rotationally Raised series:

You can also check out a farminar Matt hosted a couple years ago with Dick Sloan and his  presentation from the 2016 small grains short course at the PFI Annual Conference.

In Iowa, most of this research and most farmers’ experience has been with adding oats and/or hay to their rotation. But now, with more and more people planting cover crops – and most of them planting cereal rye, more and more people have been raising it for seed. Saving a few dollars on cover crop seed is great, but the real opportunity comes after rye harvest when you can grow another crop.

Many people in that boat are planting multi-species cover crop mixes, and for farmers with cattle, that’s tough to beat. A balanced grazing ration that likely includes a few protein sources and plenty of sorghum-sudan grass is a great way to save money on hay costs later in the year, and maybe be able to rest some permanent pastures in the fall so they’ll produce better next year. Learn more about what farmers with livestock are planting after small grains harvest in this episode of Rotationally Raised:

Growing Your Own Nitrogen

But for row crop farmers, harvesting small grains during the summer presents a perfect opportunity to grow some nitrogen. It’s something organic farmers have been doing for years to augment manure as a nitrogen source. However, most organic farmers either have hay in their rotation or grow oats, a spring small grain, and seed red clover with the legume/forage hopper of their drill at oat planting time.

Mid-summer-seeded cover crop mix (on left) and the underseeded red clover (on right) a few months after an oat harvest at Doug Alert and Margaret Smith’s farm on Oct. 14, 2016.

Mid-summer-seeded cover crop mix (on left) and the underseeded red clover (on right) a few months after an oat harvest at Doug Alert and Margaret Smith’s farm on Oct. 14, 2016.

But what about seeding clover into an already established winter small grain, like rye or winter wheat? Can you do it? “It’s always worked for us,” say Doug Alert and Margaret Smith, who own and operate Ash Grove Farm near Hampton in north-central Iowa. They’ve been frost seeding red clover into winter small grains for about the past 10 years, and have always managed to get a stand of clover established.

And, because they’re organic, clover establishment is crucial: “We can’t afford to have a failure because that’s a major source of nitrogen for the corn crop,” Doug says. Iowa State University research has shown that farmers can expect a nitrogen credit anywhere from 75 – 100 lb / acre.

Benefits of Red Clover

Dr. Bill Deen studies cropping systems and nitrogen management at Guelph University in Ontario, where winter wheat is a more predominant component of cover crop rotations. Many of his findings stem from a long-term crop rotation study started in 1980 that, among other configurations, includes a rotation with red clover frost-seeded into winter wheat ahead of corn.

“What’s remarkable about red clover is you get the N credit while simultaneously increasing corn yields,” he says – in other words, the clover provides additional benefits that increase yields above and beyond its contribution to nitrogen, a phenomena known as the rotation effect. “We’re not quite sure what the mechanisms are. Certainly it does add N to the system,” he says, “but it also seems to improve the use of N by the corn crop,” Deen suspects that it may have something do with how clover affects the soil.

The other advantage of red clover over other cover crops is that the nitrogen release pattern works well ahead of corn. “It seems to have an effect on soil nitrate that is very favorable when you look at the pattern of demand by corn,” he says. Radishes, for example, may release the nitrogen too early, and rye might hold onto it for too long. “Red clover is the most consistent supplier of nitrogen,” he says.

Bill will be hosting a farminar talking all things red clover on Tuesday, February 6, 2017 at 7 p.m. Make sure to tune in – check out the spring line-up here!

Red Clover in Practice

Two challenges to working red clover into a winter small grain system are planting and terminating. For planting, Dr. Deen agrees with Doug and Margaret – as soon as the snow is off, but the ground is still frozen, it’s time to frost seed. “Going from impassable snow to mud is often a very short time frame,” Doug says, “So you have to be ready to go when you hit that window.”

*If you’re interested in learning more about frost seeding, mark your calendar for our February small grains shared learning call on Friday, February 2 Noon-1 PM. The call will focus on frost seeding & underseeding legumes with a small grain. We’ll hear from farmer Tim Sieren of Keota and Keith Kohler, research tech for the USDA’s small grains and green manure studies conducted in Ames. We’ll discuss:
  • Ideal frost seeding conditions;
  • Equipment;
  • Selecting clover varieties for frost seeding and your management goals;
  • And which legumes should be planted instead for best effect.
To join the call dial 641-715-3620 and enter the passcode 357330#.

Frost Seeding Red Clover in Iowa

Actually doing the seeding isn’t that tough. Iowa State recommends broadcasting 10-15 lbs/ac onto frozen ground and the seeding method is likely going to be dictated by what equipment you have available. “I like that you don’t have to have a top of the line system for it to work,” Margaret says. When they first started seeding red clover into rye, Doug used a 3-point mounted fertilizer spinner, and that worked okay – he could cover a 20-25 ft. swath. Later, he switched to a grain drill and just used it as a drop seeder, but that was only 15 feet of width, and trying to cover a lot of acres quickly is tough on a drill.

So last year, he built a toolbar specifically for seeding red clover – it adds seeding capacity, and it also links into his auto-steer, which is important because he’s doing a lot of this seeding at night, when the ground is nice and hard. His setup – shown in the photo – is a Gandy Orbit-Air seed hopper mounted on a used sprayer boom with a hydraulic metering system.

Doug Alert built this dedicated toolbar for frost seeding red clover. It’s a Gandy Orbit-Air seed hopper mounted on a used sprayer boom with a hydraulic metering system.

Doug Alert built this dedicated toolbar for frost seeding red clover. It’s a Gandy Orbit-Air seed hopper mounted on a used sprayer boom with a hydraulic metering system.

With this setup, he can seed 40 acres between fills and because he can drive 7-8 mph he can cover around 20 ac/hr. “This is all very important because of the small time window,” he says.

And, some years, the window is too short, and they don’t get a chance to frost seed. But they still seed it, even if it’s a little late, and haven’t had a failure so far. And that’s not necessarily intuitive. “Clover’s low-light tolerance is phenomenal,” says Margaret, “To me, it looks like it should never survive,” when looking at the thick blanket of rye that soon covers the clover, but adds that they’ve never had a problem getting a stand of clover established.

Red Clover Termination Before Corn

Once it’s seeded, there’s little management of the clover between seeding time and termination prior to corn planting. And because Doug and Margaret are organic, herbicide termination is not an option. Instead, they have traditionally plowed the clover as soon as they could in the spring; likely right after oat planting is done. They’ve been debating whether the plow is the right option for termination – or whether a lighter tillage pass would be sufficient – and whether spring or the previous fall is the appropriate time to terminate.

For conventional farmers, light tillage and plowing are still options, but termination with herbicide can also do the job. Penn State University Extension – where red clover is more commonly used as a cover crop – has some good guidelines. They recommend the following: “An excellent herbicide program to terminate a red clover stand prior to planting corn is one pint of 2,4-D LVE and one pint of dicamba (Banvel or Clarity). Apply 2,4 D and/or dicamba 7 to 14 days prior to or 3 to 5 days after corn planting if corn seeds are planted at least 1.5 inches deep. Do not plant soybeans after dicamba application. Applying 1 to 2 pounds per acre of atrazine will help provide additional control of the red clover. Glyphosate or paraquat alone are not recommended to kill a legume such as red clover.”

Red Clover Green Manure Resources

Practical Farmers of Iowa continues to conduct on-farm trials on the usage of red clover as a cover crop. PFI members have conducted research on many of the topics discussed in this article, from comparing red clover to mid-summer-planted mixes, to the nitrogen value of red clover, to interseeding clover into winter rye, and much more. To find the results of these trials, check out and search for “red clover.”

Here are a few:

Underseeded vs. Mid-Summer-Seeded Green Manures for Corn (2018)

Effect on corn of green manure cover crops established with cereal rye seed crop (2017)

Corn Following Green Manure Cover Crops Established with Small Grain (2015)

Timing of Nitrogen Supply to Corn from Spring Terminated Red Clover (2015)

Green Manure Cover Crops Established with Small Grains (2014)

Nitrogen Replacement Value of Red Clover (2014)

Interseeding winter rye with red clover (2014)

Establishing Red Clover, Hairy Vetch and Turnips at Last Cultivation of Corn (2010)

Iowa State University also has a good production guide on using clover with winter small grains: “Intercropping Winter Cereal Grains and Red Clover” (PM 2025).

In Iowa, cover crops are typically either aerially seeded into standing corn around the time of physiological maturity in late summer or drilled immediately following corn harvest in the fall. However, the earlier one can seed a cover crop, the more potential for growth and biomass production. An earlier seeding date also opens up the opportunity for more diverse cover crops like brassicas and legumes that need more time and heat units to grow than common cover crops like cereal rye.

Farmer researchers Jack Boyer and Jeremy Gustafson interseeded cover crops (cowpeas, annual ryegrass, rapeseed) into corn at the V4 stage in June. Corn hybrids chosen exhibited vertical and horizontal leaf orientations to test whether more light penetrating the corn canopy would encourage successful cover crop establishment and growth.

Read the full report here: Corn Leaf Architecture for Interseeded Cover Crops.

Interseeding cover crops cover shot

How Was the Trial Conducted?

  • Corn planting date (both hybrids): Boyer = Apr. 25; Gustafson = May 5
  • Cover crop mix interseeding date: Boyer = June 14; Gustafson = June 16
  • Cover crop mix seeding rates: Cowpeas (60 lb/ac); annual ryegrass (22 lb/ac); rapeseed (7 lb/ac)
  • Corn harvest date (both hybrids): Boyer = Nov. 4; Gustafson = Oct. 25


Aboveground biomass of the cover crop mixes was not sampled but photographic evidence shows that cover crops persisted beneath the corn canopy into early fall at both farms.

Cowpeas emerging in corn on June 19, five days after being seeded at Jack Boyer's farm near Reinbeck.

Cowpeas emerging in corn on June 19, five days after being seeded at Jack Boyer’s farm near Reinbeck.

Cowpeas in corn shortly after a frost in October at Jack Boyer's farm near Reinbeck.

Cowpeas in corn shortly after a frost in October at Jack Boyer’s farm near Reinbeck.

Cowpeas in corn at Jeremy Gustafson's farm near Boone in mid-September.

Cowpeas in corn at Jeremy Gustafson’s farm near Boone in mid-September.

Corn yields at Boyer’s were affected by the hybrid (horizontal leaf architecture vs. vertical leaf architecture) and the interseeding. See figure below.

Corn yields at Jack Boyer’s farm (Reinbeck) as affected by corn leaf orientation (horizontal vs. vertical) and the interseeded cover crop mix in 2017. If the difference in yield between any two treatments is greater than the least significant difference (LSD), the treatments are considered significantly different with 95% certainty.

Corn yields at Jack Boyer’s farm (Reinbeck) as affected by corn leaf orientation (horizontal vs. vertical) and the interseeded cover crop mix in 2017. If the difference in yield between any two treatments is greater than the least significant difference (LSD), the treatments are considered significantly different with 95% certainty.

At Jeremy Gustafson’s, corn yields were not affected by hybrid or planting population. All strips were interseeded. See figure below.

Corn yields at Jeremy Gustafson’s farm (Boone) as affected by corn leaf orientation (horizontal vs. vertical) and planting population 2017. All treatments were interseeded with the cover crop mix.

Corn yields at Jeremy Gustafson’s farm (Boone) as affected by corn leaf orientation (horizontal vs. vertical) and planting population 2017. All treatments were interseeded with the cover crop mix.

“The seed germinated well,” Gustafson said, seeing mostly cowpeas by mid-September. “Not much made it into fall, though. Leaf architecture didn’t seem to matter and lack of rain really played havoc with this trial.”

“This technique requires more testing before wide spread adoption,” Boyer said. “I need to understand what caused the yield hit. The cover crop species I interseeded worked with both corn varieties, so I will probably try another interseeding with just one variety.”

For more details on this trial, read the full report: Corn Leaf Architecture for Interseeded Cover Crops.

This project was supported by the Walton Family Foundation.

For more information about this study and other studies as part of PFI’s Cooperators’ Program, contact Stefan Gailans at [email protected]

It’s hard to pick just one favorite part of the PFI conference, but I think mine is our potluck and this year we have a special treat – a whole roast pig from one of our members! Please join us Friday January 19 from 7-11 pm for a shared meal hosted by Ty and Bobbie Gustafson of Story City Locker and Donna Prizgintas and Lonna Nachtigal of the DonnaLonna Kitchen Show. Practical Farmers will provide a main dish, coffee, water and tableware. Please bring a side dish and beverage to share.

Potluck is held at CMPI Event Center (2321 North Loop Dr.) in Ames. Friday January 19, 7:00-11:00 pm.

A long line of people select food from a huge table laden with dozens of brightly colored dishes of food.

2017 PFI Potluck

PFI will provide:
  • A whole roast pig from Crooked Gap Farm, roasted by Story City Locker;
  • Buns from Madrid Bakery;
  • Salad greens from Lee’s Greens;
  • Beans from PFI member Darren Fehr;
  • Coffee and water;
  • Tableware.

Don’t want to keep food cold or warm all day? You may drop food off at Scheman when you arrive for the conference and we will transport it for you! Items can be dropped off on a designated table on the ground floor at Scheman. We will transport food from there until 5 pm 1/20/17. We can plug in crock pots and refrigerate dishes.

Need to pick something up last-minute? Visit one of these local establishments:

Don’t miss this fun family event! 

Two young boys, one holding a big brimmed hat talk to two men who are seated at a table enjoying food and beer. In the background you can see many tables full of people eating.

PFI staffer Stefan Gailans and PFI member Jeremy Gustafson are entertained by two youngsters at the potluck.

Dave and Meg Schmidt operate a diverse livestock farm, Troublesome Creek Cattle Co., in Exira IA; raising grass-fed and finished cattle and sheep, pigs and poultry. Feeding the 100% grass-fed cattle herd over the winter is a great expense, so they have experimented with feeding different forage sources- hay, cover crops, crop residue and stockpiled pasture to minimize costs. Hay is the most expensive forage to feed during the winter, so the Schmidt’s were curious how the could extend their grazing season and decrease the amount of hay they have to feed.

The full Practical Farmers’ Research Report is now available.

Sylvie Schmidt checking on cattle as they graze stockpiled perennial pasture.



This research was conducted during the non-growing, winter seasons, from 2013 to 2017. The Schmidts recorded the movement of animals through different lots and pastures, tracked weights on a monthly basis, and noted the amount and value of feed consumed.  Monitoring began when animals finished the normal summer grazing and moved to winter crop fields or stockpiled pastures – approximately November through the end of April.

Cover crop grazing

Cereal rye, wheat, hairy vetch and/or oats were planted three out of the four years, for the purpose of grazing during the winter. Table 1 shows seeding records and costs. In 2013-2014 and 2014-2015, cover crops were aerially seeded by a neighbor. In 2016-2017, cover crops were drilled by Dave.

table 1

Stockpile grazing

Stockpiled forage in the pastures was comprised of orchardgrass, red clover, smooth brome grass, tall fescue and Kentucky bluegrass. Generally, the Schmidts stopped grazing pastures in August in order to grow enough to stockpile for winter.


The percentage of hay consumed by the cattle herd during each non-growing season is shown in Figure 1. The remainder of the herd’s ration was fulfilled by a mix of cover crops, crop residue and stockpiled pasture, depending on the year. Herd size is listed in animal units (AU) which equate to 1,000 pounds of animal.

Figure 1

During the winters of 2013-2014 and 2014-2015, cover crops and crop residue provided almost half of the winter feed needs for the herd. During the winter of 2015-2016, the most hay was fed, because the farmers were not able to plant cover crops the season prior. The least hay was fed in 2016-2017, due to a combination of grazing stockpiled pastures along with cover crops and crop residue.

Growing animals were weighed approximately once a month. The weights nearest the beginning and end of the winter feeding period were used to figure average weights and average daily gains (ADG). “Last year [2016-2017] was our first time with significant stockpile grazing and the finishers are the heaviest we’ve ever had them at this point in time. We were able to dramatically reduce the amount of time the cattle were fed hay in the lot – roughly early February to mid April. Perennial stockpile really pays because we can graze it shorter to the ground when it’s dormant, so animal days per acre go way up” stated Dave.

Figure 5

Utilizing diverse winter forage sources allowed the Schmidts to feed less hay, increase the size of their herd and save money.  The Schmidts concluded that incorporation of stockpiled pasture is necessary to decrease costs and work towards their goal of only feeding hay for one month per year. To see a detailed cost comparison and to read more about calf and feeder weight gains over each winter, read the full report here.

“We should be able to graze stockpiled annual and perennial pasture well into December. When that feed source is gone we will feed baleage; wrapped oats that were cut at flowering and wrapped alfalfa and orchardgrass. Once that’s gone we’ll have to buy dry hay.”  Dave and Meg hope these research results aid other farmers when deciding how to extend their grazing season and cut winter feed costs.

Kathy Voth

Kathy Voth is one of the featured speakers at Practical Farmers of Iowa’s 2018 annual conference (Jan. 18-20, in Ames), and we’re excited she’s able to join us. Kathy publishes the popular weekly online grazing magazine, “On Pasture,” in partnership with Rachel Gilker.

For 12 years, Kathy also worked with the Bureau of Land Management, working with ranchers, university researchers and agency staff to develop solutions that help communities live sustainably in their environment. In 2004, she developed a method, based on principles of animal behavior, for teaching cows to eat weeds.

I chatted with Kathy to learn a little more about why she advocates that farmers reconsider the place of weeds in their pastures. It turns out that weeds are highly nutritious for cattle, in addition to their abundance and resiliency to weather — and that cattle, just like people, learn to eat the food they grew up seeing their mothers and elders consume.

Kathy will lead a workshop on this topic, “Teaching Cattle to Eat Weeds,” at our annual conference next month. Visit to learn more or register.

Here’s what Kathy had to say to some of my questions.

When you first developed the concept of teaching cows to eat weeds, around 2004, it was a pretty radical idea for graziers. Have you seen more buy-in to this idea over the past 13 years?

That’s not changed – it’s still a pretty radical idea. Most people think that cows eat grass, sheep eat forbs and goats browse brush. What it comes down to is animals eat what they’ve learned to eat. Our thoughts about what animals eat really restricts us and them.

It kind of goes in waves. For a while I worked really hard at getting the information out. One time, I went to Missouri and when I came back, told my dad how people had pretty much laughed at me. Then five years later, they invited me back to the same conference to talk about the same thing.

My dad said I probably shouldn’t go. Well, I went and they thought I was the greatest thing. It depends on what people are ready to think about and accept, and you just have to be there at the right time.

What do you consider a pasture weed?

Lots of people are really hung up on the idea that a weed is bad and should be killed, but a weed is just a plant out of place. I think weeds are an all-around good thing.

Even among domesticated cows, different groups eat different things. I was in Boulder County, Colorado working with a group of cows, and they were pretty much eating anything. I thought, ‘I’m going to take in every single plant they’re eating and test it.’ It was like 20 plants. One was field bindweed. They’d been eating that long before I showed up.

A lady at the testing facility said she’d really like her cows to eat field bindweed – her cows didn’t have this particular culture. There are examples of cows eating all kinds of things.

From my perspective, we have wasted way too much time and money managing weeds and should let our cows eat them. The beauty of the process is that you train one group of animals to eat one weed and watch them in pasture. They will generally try other new plants on their own, because the training process opens their eyes to the possibility that other things can be food.

Mostly, we try to manage for grass.

Why do you think that is? If cows have these potentially diverse food cultures, why do you think there’s this misconception about and focus on grass?

My theory is the reason we think cows’ [only natural diet is] grass is that, when we could start to harvest forages and store them for long-term, about the time we got mechanized enough to do that, grass was an easy thing to store. So that’s what we fed them – the more grass you have, the more you have to store.

Back in the 1750s to about 1850, people thought cows ate carrots, beans, potatoes and turnips – things we’d never think of feeding them. That just pointed out to me that cows are flexible. It’s people who are inflexible.

Have you ever heard back from anyone who was initially skeptical of teaching cows to eat weeds, but had a change of heart?

I’ve had lots of people that were really skeptical and went ahead and did it – like one guy in Montana. I think he got roped into the project by a gal he worked with at [a natural resources conservation office]. I sent him instructions, he started training and I came out to help. Sure enough, [the cows] started eating some weeds, then other weeds.

The heifers we had trained he had in a pasture divided in half with a single wire. The steers on the other side of the wire learned how to eat the weeds from the heifers – so he was very sold on it.

The guys I worked with in Bolder County, Colorado were like, fine, we’ll give you some cows to work with but we don’t want to be involved. I would do different projects with these cows, trying them on different weeds. Eventually their owners became my friends. The last year I worked with them, they had a herd of 800 cows.

I didn’t always get the same cows, and the ones I trained that went out with the herd taught others. It took about six years of sorting cows – but now they run for the weeds first.

What that guy was really impressed by was that some of the native plants were making a comeback.

If graziers already feel they’re doing a good job managing their pastures, is there still a reason they should consider training their cows to eat weeds?

If you know what you’ve got in your pasture and know what you’re managing for, you can do a good job and maybe you won’t have any issues.

The problem comes when something bad happens – it gets dry, you’re managing as best you can but you overgraze. These accidents happen often, because weather changes often. Suddenly you have more cows than you thought.

My thought with [developing this approach] was that if my cows know how to eat weeds, I don’t have to worry because weeds are very resilient. They come up during drought, so my cows will always have something to eat.

Grazing weeds is a strategy for resilience. Plus – nobody knows this – weeds are more nutritious than grass. They are basically the equivalent of alfalfa or better.

Protein is one of the limiting factors for most cattle; it’s a hard thing for most cattle to get. Weeds are very high in protein, and very digestible. That means cows can gain weight even if their pastures are lower quality.

Any time an animal has protein and dry grass, they can eat all that dry grass as well and still get an adequate diet. The protein helps them process dry food better.

You might even be able to raise more cows – you basically have 43 percent more forage if you teach your cows to eat weeds.

Does your method for teaching cows to eat weeds work just as well with older animals? For graziers who want to start doing this, would they need to plan for a longer training period?

I started with heifers because we all believe younger animals learn more quickly than older ones. But then I started training anything that anyone brought me and it always worked.

Some individuals are better weed-eaters than others, but it wasn’t breed-specific, it wasn’t age-specific. If a mother cow was a really experimental eater and would eat a lot of new things, her calves were also like that – because I got to follow some of the calves over a number of years and watch their offspring.

The bulls were really interesting, because I would teach the heifers and they would put the bull in for just a day, and he would learn really fast – I think because he was trying to impress [the cows] and fit in.

The cows have taught me a lot over the years.

How do cows compare with goats when it comes to tackling pasture weeds? For graziers who do mixed-species grazing and already integrate sheep or goats, is there still a reason for them to consider training their cows too?

Goats don’t do a better job. I did goats for a long time and did prescribed grazing with them. What I found is cows are every bit as good as goats.

The reason I would always choose cows over goats is cows are so much easier to manage and sell on a market than a goat is. It depends on where you are – I think the goat market is getting better. But building fence for goats is so hard; they’re just so smart. But a cow, I can build a one- or two-strand fence and they’ll stay in.

I tell people if you already have cows and just want to get goats to manage weeds, don’t do it. Cows can do every bit as good as goats – even on brush.

But if you think you have a market for the goat or just happen to like goats and sheep, then that’s fine. I would probably still teach the cows to eat weeds.

First I would watch what everybody is eating, because before I knew cows could eat weeds, I knew there was research showing that you could put five goats per pasture and everyone would eat well. But I’ve since found it’s maybe 2.5 goats or 3 sheep per pasture.

Once cows have been trained to eat weeds, how much active pasture management is needed? Do you still have to get rid of noxious weeds?

For example, in Montana, they have a lot of spotted knapweed and really need to reduce that. To do that, there are times you really should put your animals in a pasture. I would do that in mid-July for Montana, because at that time your other plants have senesced. You’ll have grazed your spotted knapweed before it goes to seed, even if it flowers after that, research has shown that most of the seed isn’t viable.

You could manage timing that way.

One of the reasons I really thought training cows to eat weeds would be a good thing is because, while you can put up multiple fences and force cows to eat everything, in some places that’s not viable – the landscape is too big, or water sources aren’t close enough together. My thought is a if cow is out there 24/7 and knows to eat weeds, you don’t have to do anything about it.


You finally did it. You took the leap of faith and grew small grains last year. Everything went great – you got your weeds back under control and grew an amazing clover cover crop. Next year you’re going back to corn – but, uh oh, hold on, it’s not business as usual. Now that you’ve grown biological nitrogen with your cover crop you’ll need to adjust your nitrogen plan. And what about terminating that clover before corn? You’ve heard that can be a real chore. PFI members Randy and Willie Hughes, who operate a 5,500 acre split conventional and organic farm in southern WI, joined us for our December small grains shared learning call to address these questions.

Fifteen people pose and smile in front of a green and yellow john deere tractor

The employees and family members that make up the Hughes Farm. Randy Hughes stands in the front row on the far left and Willie Hughes is in the back row on the far right. Photo from:

Adjusting Your Fertilizer Plan

The first step in deciding how much nitrogen you’ll have to purchase this year for your corn is figuring out how much you already have in the plant matter and the soil from your nitrogen-fixing, legume cover crop. As with different fertilizer products, no two cover crops are created equal in terms of the nitrogen they provide. The amount of nitrogen fixation depends on the biomass produced by the plant and how long it’s been in the field. Luckily, the Hughes provided some rules of thumb that can help put a number to this N source:

Cover Crop Biomass Amount of N
1 Year Alfalfa Over ankle high 100 lbs/acre
2 Year Alfalfa Over ankle high 200 lbs/acre
Clover Way above ankle but below knee 80 lbs/acre


It’s important to note that all of the legumes listed in the table above are planted in July or August in the year preceding the corn, after wheat is harvested in the Hughes’s operation. “You won’t get nitrogen out of it if it’s only got a couple months of growth,” Randy says, “so it’s got to go in after a small grain.”

But, N in the cover crop is not necessarily correlated directly to available N in the soil that corn can use. So the Hughes designed a study to see which fertilization strategy created the most available N. They compared two different legume cover crop treatments and two manure treatments that varied the time of cover crop planting and manure application. The cover crop treatments were alfalfa planted after oat harvest (summer) or winter wheat with alfalfa drilled into it in the spring. The manure treatments applied 6,000 gallons of hog manure into a non-legume cover crop after wheat (summer) or applied in the spring before soybean planting.

Blue semi with Hughes written on the side sits in front of a field of wheat with wheat straw in wind rows

Wheat harvest on the Hughes’s farm with the green of an underseeded legume peeking through the wheat stubble. Photo from:

They found, as they expected, that the legume cover crop with more growing time produced more available N, but both cover crop treatments actually had higher N concentrations than either of the manure treatments. The frost seeded alfalfa into wheat resulting in 26 ppm of available N in the soils, alfalfa planted after oat harvest rang in at 20 ppm, hog manure applied after wheat was 14 ppm and spring applied N was only 10 ppm. Through this project the Hughes learned that their green manure strategies were highly effective at providing available N to the subsequent crop.

Terminating the Cover Crop

While you want to give the cover crop as much time to grow as possible to maximize the available N, we also know that killing it before corn planting to avoid yield drag can be tricky. As Willie says, “You’ve got to get it dead or it’ll be a weed for you too.” Their preferred implement is the disc, a fifty foot sunflower 1550, though they say plowing or chiseling could work. They perform 1-2 passes with the disc when the soil temperature is at 45-50 degrees and then plant corn when soil temperature reaches 60 degrees.

One benefit of the nitrogen provided by plowing in the cover crop, often referred to as a green manure, is that the nitrogen is not as susceptible to leaching. “If you get four inches of rain in the conventional world you lose four inches of nitrogen, but with the legume breaking down it doesn’t leach away because it’s not soluble yet.”

When it comes the balance sheet, the Hughes see the benefits. “Small grains have made or saved more money organically than they have conventionally,” Randy says. “You can buy nitrogen conventionally about as cheap as you can grow it, but in organic you can’t.”

Every month we host a shared learning call featuring on growing or marketing small grains. If you’d like to join our next shared learning call, email or call 515-232-5661. Learn more about our small grains cost share or other programming at .

After completing two years of cucumber enterprise budgets, Ann Franzenburg and Emma Johnson looked at their farms and decided: “Let’s do cherry tomatoes.” For this enterprise budget, both farmers did a careful accounting of the revenue, costs, and labor for their 2017 cherry tomato crops. The analysis of their data, and their comments on varieties, harvesting, and marketing, is available in a new Practical Farmers’ Research Report: Enterprise Budget for Cherry Tomatoes.

Johnson cherry tomato

Key Findings

  • Both farms had profitable cherry tomato crops, netting $1.31/lb at Franzenburg and $1.54/lb at Johnson
cherry tomato fig 1

  • Labor was the largest expense for both Franzenburg and Johnson, accounting for 62% and 68% of their total expenses, respectively.
  • Harvesting and packing was the most time-consuming task on both farms, accounting for 74% of labor-hours at Franzenburg and 62% of labor-hours at Johnson.
cherry tomato fig 4


Franzenburg and Johnson both plan to repeat the cherry tomato enterprise budget for 2018 to provide a two-year look at the crop’s production and profitability.

Click here, or on the image below to download the full report.

cherry tomato cover



Carmen Black and Mark Quee raise sheep on their diversified vegetable farms. They were curious if grazing a cover crop prior to a fall crop, rather than simply terminating the cover crop by mowing and tillage, would have an impact on the yield of the next crop. For this trial each farmer measured the yield of a fall brassica crop following grazed and un-grazed cover crops. Said Black, “I’m interested in finding ways to incorporate my sheep into my vegetable operation more holistically, but also in compliance with food safety regulations. This trial will allow me to see if there’s any measurable difference right away.”

The full Practical Farmers’ Research Report is now available.


Farmers set up plots in a randomized, replicated pattern. During the spring, a cover crop of oats and peas was seeded to all plots. Farmers used moveable electric fence to exclude the sheep from control (cover-only) plots, while the treatment plots were grazed. Quee grazed sheep in the plots on May 30; Black grazed sheep in her plots on June 5. Biomass samples were taken from all plots by clipping aboveground foliage at ground-level (four 1-ft2 quadrats per plot), air-dried and weighed at the Practical Farmers of Iowa office. Biomass results are reported on a dry matter (DM) basis. Production practices, grazing, planting and harvest information for each farm is available in Table 1.

grazing table 1

After termination of the spring cover crop by grazing or mowing and tilling, Black and Quee seeded fall brassica crops. The rows ran the length of the plots. Quee measured broccoli (cv. Gypsy) yield; Black measured Brussels sprouts (cv. Diablo) yield. Planting, management and harvest practices were consistent across treated (grazed) and control (un-grazed) plots. For broccoli, Quee counted, weighed and measured the width of heads in each plot. For Brussels sprouts, Black harvested entire stalks, then counted and measured sprouts, and graded sprouts based on USDA criteria for color and firmness, by plot.


Sheep graze the treatment plot at Quee’s.

Quee incorporates the cover crop during the trial.

Quee incorporates the cover crop during the trial.

black brussels

Brussels sprouts being measured at Black’s.


Brussels sprout yield at Black were not statistically different in grazed and un-grazed plots; only color ranking was statistically different, with the grazed plots tending lighter green than un-grazed
plots. Average number of sprouts per plant was 76.6 in the grazed plots, and 64.9 sprouts/plant in the un-grazed plots. Sprouts in grazed plots, on average were slightly larger and more firm than in un-grazed plots, but the means were not statistically different. “Sometimes you imagine you see a difference in the treatment plots,” said Black. “Just looking at the plants I didn’t think there was a difference. And even though the means are not statistically different, 12 sprouts per plant is a big difference. It shows the importance of actually counting,” she said.

grazing fig 4

Quee had nice sized broccoli crowns, though the average weights were not statistically different by treatment. Crowns averaged 1.44 lb/crown and 1.35 lb/crown for the grazed and un-grazed plots, respectively. There was not a statistically significant difference between plant yield (lb/ft2) or crown yield (crown/ft2).

grazing fig 5
Broc harvest 2017

Broccoli harvest at Quee’s.

Black is interested in grazing more spring-seeded cover crops based on trial results; Quee plans to stay with his current system of grazing in fallow years and in the early spring and late fall.

Click here or on the image below to view the .pdf of the full research report.

grazing cover

As farmers wrap up their season and plan for next, PFI’s farmer-cooperators have an additional responsibility: submit the data they collected from this year’s research trials and plan next year’s projects.

The first week in December marks the annual two-day Cooperators’ Meeting where farmer members meet to discuss these research results with each other and plan on-farm projects for the following year. In preparation for this meeting, staff members in Practical Farmers office are busy collecting this data, analyzing it and publishing the findings in detailed research reports for sharing far and wide.

In 2017, 51 farmer-cooperators participated in 71 projects that concluded or are still on-going.

2017 On-Farm Research Project Locations:

2017 Cooperators Program Map

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