Cover Crops at Work

By Daniel Hudson, University of Vermont Extension Agronomist

In solidarity with interest groups concerned about anthropogenic climate change, I have installed solar panels. In our basement. They seem to work best when the bulkhead doors are open and/or when the basement lights are turned on. If it doesn’t work out, that’s okay because I paid for it with Federal funds allocated for this purpose (thanks, by the way!). While the solar panels are great, what I am most excited about is my new wind turbine…..

As ridiculous as that sounds, is it possible that cover crops following corn silage are often managed in a similar manner? Sure, we ‘use cover crops’ and you can see green from the road, but when they consistently function at a fraction of their potential, they are little more than window dressing. Managed optimally, cover crops have immense potential to 1) improve soil quality; 2) prevent nutrients from leaving the field; 3) stabilize the soil and prevent erosion; and 4) contribute to the feed supply. The biggest advocates of cover crops that I have met are the farmers who have worked very hard to make them as functional as possible.  Understanding how cover crops interact with soil and water is essential as we move toward making cover crops functional in our fields.

Promoting the ‘Slow-Water Movement’

Remember how our rivers, creeks, driveways, and roads were rearranged by Tropical irene erosionStorm Irene? Moving water is erosive. Water moving fast is more erosive. Fast-moving water carrying soil particles, rocks, and boulders is even more erosive. Anything we can do to slow the water down and reduce the amount of soil that it is transporting, will reduce its erosive power. Like logs in the creek, plant stems, leaves, and crop residue on the soil surface present a physical barrier to moving water. This lower water velocity promotes water infiltration and allows soil particles to settle out of the moving water. The best agricultural soils will allow a moderate rate of water infiltration. If infiltration is slow and/or precipitation is rapid, water will eventually begin to pool or move downhill. Having many little barriers along the way will slow that water down.

Sticking together


In his 1969 hit song, B.J. Thomas was the first to recognize the potential adverse impact of raindrops when they keep falling on one’s head. His observations led a crack team of UVM and USDA soil scientists to investigate whether raindrops could have similar adverse impacts on soil and the environment. To their dismay, they discovered that B.J. was onto something. Their groundbreaking research culminated in the birth of the North American Cover Cropping Movement in 1970.

Hitting the ground at 20-25 miles per hour, raindrops have significant energy that can cause soil particles to detach. When those detached particles begin to move with water, they collectively increase the erosive force of runoff by scouring the surface of the ground/channel as they move.

Healthy soils are teeming with life and are less prone to erosion because resident microbes macro-organisms in the soil secrete and excrete substances that cause soil particles to stick together. Soil binding substances have their limits, however, and a raindrop hitting soil will dislodge some soil particles. Promoting healthy soil with active microbes and macro-organisms that secrete these substances will reduce detachment of soil particles by raindrops or moving water. In addition to the roots physically holding soil in place, decomposed/decomposing cover crop tissue provides food for soil organisms and ultimately contributes to soil stability.

Physical protection

Protecting at least a portion of the soil from direct impact of raindrops is one way to reduce detachment of soil particles and subsequent soil loss. In addition to slowing movement of surface water, well-established cover crops function as a physical shield that dissipates the energy of incoming rain drops, reducing the amount of soil that is detached. In areas where wind erosion is a concern, cover crops physically protect the soil in more than one way.

Consider the picture below. Is the cover crop in the circle on the left likely dissipate the energy of raindrops or slow movement of surface water? Will its root structure do much to stabilize the soil? Probably not. Can it still help to improve the soil quality in the long-term? Maybe, but probably not noticeably and its overall value to the farm and the ecosystem is open to question.making cover crops work picture

The reality is that if the cover crop is weak, thin, and scarcely visible when looking straight down at it (i.e., as opposed to how it looks from the road), it probably isn’t doing much, and certainly not as much as it could if managed optimally. The good news is that there are several realistic approaches that can result in excellent stands of cover crops in most years, but it requires a bit of planning

Getting your cover crops planted early is essential for optimizing cover crop performance.  Here are some practical considerations when planning for the 2016 cropping year.

  • The correlation between corn relative maturity and yield is not linear or perfect and planting shorter-maturity corn hybrids is a good option for many. While long-day corn can occasionally give you ‘slam dunk’ yields, such varieties can be the cause of economic pain if they fail to mature. There many varieties of shorter-day corn that will yield as much or more than longer-day corn yet give you more of a chance to plant cover crops on time. Work with several seed vendors to plant small plots/strips of various corn varieties with a range of maturities. It is also a good idea to work with your consulting dairy nutritionist to get feed quality reports for each variety.
  • Planting your corn late often begets late harvesting (and late cover crop establishment). Would you be well-served to own a corn planter rather than relying on custom operators? While I believe that custom operators are a valuable part of the agricultural economy, they still can only be at one place at one time. Between the demand for their services and unfavorable spring weather, significant delays in corn planting often delays harvest, reduces yields, and adversely affects the quality of the corn silage (less starch). It is not hard to imagine a corn planter paying for itself in a year or two just in increased yield and quality.
  • Could no-till planting work on at least some of your fields? In many cases, the spectrum of attachments for ‘no-till’ planters can overcome many of the problems associated with earlier generations of no-till equipment.   Depending on soil particulars, having the option to plant no-till can often get you into the field earlier, yet without compromising yield.
  • Done right, interseeding cover crops is a promising idea (again). The Penn

    State Interseeder is an intriguing tool that can function as a regular no-till drill when it is not used for interseeding, and the cost is similar to regular no-till drills. It can be fitted to apply sidedress nitrogen and/or spray weeds at the same time interseeding is being done. Given the diverse landscape, time of planting, and weather, a substantial opportunity for custom interseeding of cover crops seems to exist.

  • What herbicides are in your weed control program? Your weed control program can narrow your options for cover crop species and/or your ability to harvest the cover crop in the spring. If you want to harvest your cover crops for livestock feed, you need to consult with your custom applicator in advance.
  • Broadcasting cover crop seed into standing corn is a gamble. It will work sometimes in some parts of some fields, but here is no substitute for seed-soil contact. Getting the timing right can help, but the right timing is largely determined by the weather and more easily identified in hindsight. Shade, lack of water, and sub-optimal seed distribution can all result in sub-optimal stands.
Posted in Uncategorized | Tagged , , , , , , , , , , , , , , , , , | Leave a comment

Elements of Soil Health


‘the poor part of the field’ Photo by Daniel Hudson

Every experienced farmer can identify the best and worst soils on their farm, and they usually have a theory or two about what makes them that way. While there are technical words that soil scientists use to describe soils, farmers tend to use big picture adjectives to communicate the some of the same concepts: droughty, mellow, dead, wet, tight, poor, acidic, compacted, eroded, etc. Recently, though, the terms ‘soil health’ and ‘soil quality’ have become more popular with government agencies and the terminology has trickled out into the rest of the industry. But what do these terms really mean?

Consider human health: we can use some basic tests to determine whether a person has major health risks. When major risks or problems are identified, health care professionals often can use a set of information about human biology, diet, and exercise to help us move toward our personal theoretical optimum. It is the same with soils. Like your own body, soil is an amazing and complex system. Once we appreciate what is going on below the soil surface, we can begin to make management decisions that will result in a healthier and more productive soil.


Given a set of inherent soil properties (soil texture, drainage), and a range of uncontrollable environmental factors, healthy agricultural soils will:

  1. efficiently cycle plant nutrients with minimal soil loss;
  2. over the long-term, will maintain or increase water-holding capacity, aggregate (particle) stability, and soil organic matter;
  3. have stable or declining root penetration resistance over time;
  4. have a stable or increasing water infiltration rate over time (especially the more naturally restrictive soil types); and
  5. yield at or near their theoretical yield potential.

 pH, Free Aluminum, and Root Health

Because of past reports of a connection between aluminum and Alzheimer’s disease, it is not unusual for people to get excited or even slightly panicked when they see aluminum reported on their soil test report. How in the world did it get there? Answer: it has been there as long as the earth existed. Aluminum is the third most abundant element in the Earth’s crust, coming in at 8%, behind oxygen (47%), and silicon (27%). Most of this aluminum is bound in stable compounds and is not freely floating around in solution.   ‘Free’ aluminum (Al3+) is toxic to plant roots and also immobilizes phosphorus in the soil, which is the reason it is a major concern for crop production and included on your soil test report.

If you had to spend five minutes in a room that had a marginally low level of oxygen and high levels of cyanide gas, which you be more concerned about? Personally, I would be more worried about the cyanide. While not as acutely toxic to plants as cyanide is to humans, high levels of free aluminum (Al3+) is among the greatest concerns for our crops.

wheat with stubby roots

Wheat plant with stunted roots and secondary disease due to soil acidity. Photo by Daniel Hudson

Some will say that plant roots are the foundation of soil health and quality. Others would suggest that soil fertility has to come first if plant roots are to proliferate. The latter view is supported by data and the experiences of many farmers and agricultural researchers. Crop roots will only thrive to the degree that their environment allows. If free aluminum levels are high in a particular soil, many crops will not thrive. The roots will likely be stubby and without much branching or fine structure. Free aluminum also willingly binds to phosphate, rendering it unavailable to plants. Correcting the problem can shift the equilibrium and allow some previously immobilized phosphate to become available to plants.

wheat on acidic soil

Wheat field with zones where soil pH was 4.0 – 4.4. Photo by: Daniel Hudson.

Soil pH has a major influence in the amount of free aluminum. The more acidic (low pH) the soil, the more the aluminum shifts from bound the free form. When lime is added to such acidic soils, much of the free aluminum is converted to a less soluble form and the soil can become much more hospitable to crop roots; pH adjustment is THE way to reduce the levels of free aluminum. The picture to the right shows a wheat field that had zones where the pH was as low as 4.0.  While some crop and non-crop plants are much more tolerant of free-aluminum than others, measuring and managing free aluminum can be a very high-value activity in crop fields.

Healthy Soils Meet Crop Nutrient RequirementsNRFCV

Crop growth is limited by the nutrient that is in shortest supply relative to the quantity needed. While all plant nutrients are important for root health, phosphorus and sulfur have notable roles in the development in vigorous roots. Healthy roots in a hospitable environment allow the plant to access more of the soil profile in order to meet its nutrient needs. An excellent resource for understanding more about crop nutrient needs is Nutrient Recommendations for Field Crops in Vermont.

Healthy Soils Hold Water

Have you ever been REALLY thirsty? Aside from ordinary drought stress, inadequate


water in the root zone induces nutrient deficiencies because roots can only take up nutrients that are dissolved and moving with water in the soil. Further, when soil moisture declines, microbial activity declines, leading to slower nutrient cycling. Given the constraints of certain soil types, soil quality/health is usually increasing if management practices result in higher water-holding capacity and increased infiltration rates.

An exception to the last statement is the case of an excessively drained (i.e., sandy), in which case improved infiltration rates do not improve soil quality. In such a case, the goal is to increase water holding capacity and reduce losses via evaporation. Addition of organic material always helps to increase water-holding capacity. While it is easy to reduce soil organic matter, it is extremely difficult to makes significant long-term improvements in soil organic matter levels in sandy soils. This is because the amount of oxygen that freely moves into and out of the soil influences how much oxygen aerobic organisms have at their disposal as they are breaking down (i.e., consuming) soil organic matter. Because tillage of coarse-textured soils has an impact on soil organic matter that is analogous to blowing on a fire and it is a good idea to consider using reduced/no-till planting methods and managing to create/maintain a surface layer of plant debris and maintain soil structure, slow microbial activity, and reduce evaporative loss.

Healthy Soils Allow Water to Move Downward


Adequate water is obviously important for plant growth, but roots need oxygen to do survive and thrive (this is why prolonged flooding and ice-sheets can kill plants). Water-saturated soils also create conditions favorable to crop pathogens.

On fine textured soils that tend to restrict water infiltration, there are three ways to improve the movement of excessive water through the soil profile, 1) appropriately constructed drainage systems; 2) physical disruption of the restrictive layer (e.g., sub-soiling); 3) facilitate the placement of organic matter within and throughout the restrictive layer. Tile drainage is outside the scope of this discussion. Subsoiling can create a temporary conduit through the restrictive layer. This can allow excessive water to pass more quickly through the soil profile to and thereby reduce the likelihood of soils staying saturated for long periods of time. It can also allow

Subsoiler, from

roots to have access to a greater volume of soil than would otherwise be available during dry periods of the summer. Subsoiling is best done when soil conditions are dry enough to allow the shank to lift and shatter the soil rather than cutting a smeared groove through the restricted layer. A shattered subsoil provides more avenues through which water can pass and roots can more easily penetrate. This and a few other types of careful soil disturbance can facilitate the deposition of organic material (plant roots) throughout the soil profile. Finding ideal conditions for subsoiling/shattering is easier in Midwestern states where wheat (harvested in July) is in the crop rotation. It is more challenging in corn silage systems in the Northeast because soils are often very moist during and after silage harvest. Unfortunately, it often does not take long for the restrictive layer to form in the zones through which the subsoiler shanks passed. One option for farmers in the Northeast is to wait to subsoil until a field is rotated back into a grass crop and to subsoil after a cutting when conditions are as dry as they typically get in our area. If that crop includes plants known to root aggressively, it is reasonable to expect that some of the grass roots will grow down through the restrictive layer. When those roots die, the deposited organic matter can result in the formation of longer-term pores that can improve water movement through the restrictive layer.

Soil workers need good working conditions!

Soil microbes are tier-1 of your workforce. The good news is that soil microbes are abundant: there are up to ten billion (10,000,000,000) bacteria in one GRAM of dry soil.

1 gram of soil

1 gram of soil

That is about 2.3 billion billion (that is, 2,300,000,000,000,000,000) bacteria in the top 3.5 inches of soil of one acre of land! There are also MANY other soil micro and macro organisms. While they are there to serve you, it is also important to understand that they are ‘unionized’ and you (as the land manager) are responsible for their work environment. If their needs are not understood, acknowledged and ultimately met, a ‘slowdown strike’ is sure to follow.

Soil microbes use the carbon portion of manure and other plant material for ‘food.’ In the process, they secrete sticky substances that cause soil to have ‘structure’ and excrete substances that have plant-available mineral nutrients. Without this process, plant material would pile up and nutrients would never be released. Without nutrient cycling, plants would not exist.

To live, soil microbes need food, water, and oxygen. The soil contains a tremendous diversity of organisms and ‘who is there’ is dramatically influenced by management. The

bacteria on plant root hair. From

vast majority (90%+) of microbial life in the soil exists within a fraction of a millimeter from root tissue. Parts of plant roots are continuously being sloughed off, parts of roots are dying, new cells are replacing dead ones, and organic compounds are continuously secreted. Dead, sloughed, and secreted plant parts/compounds feed soil microbes. In return, the microbes have the energy to break down dead plant material, re-releasing nutrients in plant-available forms. Microbial secretions cause soil aggregates to form, which allows air to move in and out of the soil, providing oxygen for both roots and microbes, in addition to improving water infiltration and reducing root penetration resistance.

Humans have found ways to partially, temporarily, and artificially accomplish some of those things without with minimal microbial collaboration. Water can be removed with drainage and added with irrigation. Tillage equipment can keep root penetration resistance low for certain periods of time while simultaneously giving the soil a shot of oxygen. In the short-term that also releases nutrients, but in the long-term it reduces soil organic matter. If nutrient cycling is poor, or if manure is not going back on the field, we can compensate with synthetic fertilizer. Equipment, agricultural chemicals, pesticides, and fertilizers are all amazingly helpful tools, but the soil is teeming with organisms and micro-organisms that provide amazing services.

If the sun shines, we are still good to grow. Right? Sort of. We can grow crops hydroponically, but it obviously makes more sense to harness the power of microbes to the degree possible.


Cover crops harness sunlight, bare soil does not. Photo by Daniel Hudson, University of Vermont

Soil health improvement is largely a solar-powered process

Sunshine falls on every square inch of your land whether a leaf is there to make use of it or not. The microbes have something to eat because the sun shone on a plant. This is why it is imperative that land managers maintain growing plants on the soil for as much of the year as possible. Sunlight falling on bare ground does not feed soil organisms. So, where there is opportunity, it is a very good idea to establish a vigorous cover crop that can become a biological solar panel (leaf) that will end up feeding the soil microbes, resulting in better nutrient cycling, more organic matter, improved soil structure, better water infiltration, and increased water-holding capacity. In a corn silage system, cover crops are an essential element to improving soil quality/health.

The ‘Big Picture’ of Soil Health

Every organism wants to thrive. It is easy to under-appreciate the influence that the local environment has on the ability of an organism to realize its potential. This is true at every level from our households down to soil microbes. My colleague John Porter (UNH Extension) tells of an instance when a dairy farmer decided to replace the barn roof – with the cows still inside. As soon as the roof came off, production went up 5 pounds/cow/day! They obviously were being held back by a ventilation problem. Plants and soils are no different, but it often takes more than a day or two to experience the benefits of improving the soil environment. Here are the basics:

  • Test your soil. It is worth hiring someone to do it if you don’t have time!
  • Address pH issues, particularly if free aluminum is abundant.
  • Correct plant nutrient deficiencies. The basics (aside from nitrogen) are phosphorus, potassium, and magnesium. The other plant nutrients are very important too but deficiencies are relatively uncommon in dairy cropping systems. If you suspect a deficiency of another nutrient, plant tissue testing can be used to diagnose the problem.
  • Increasing soil organic matter is a long-term proposition, but even small improvements can improve water holding capacity, soil structure, and water infiltration.
  • Addressing soil compaction can increase plant root access to water and soil nutrients at greater depths as well as allowing excessive water to move out of the root zone. Controlling traffic, staying off of fields when they are wet, using cover crops, and physical disruption (subsoiling) all have a role to play.
  • Focus on the plants and acknowledge the microbes. Don’t forget the importance of having living roots in the soil for as much of the year as possible. What do they need to thrive? What part of their environment is holding them back? Is there anything that I can do to improve their working conditions? Once they have what they need, they can harness solar power to do a lot of the work that needs to be done.
Posted in Uncategorized | Tagged , , , , , , , , , , , , , , , | 1 Comment

Foiled Again!

By Daniel Hudson, UVM Extension Agronomist

It has happened to us all — plans were coming together beautifully and then one trifling detail derails the whole operation. You get to the deer stand on opening day of hunting season and you realize that you left the ammunition (and/or lunch) on the roof of the truck – before you left home. Or, you get halfway to the lake for a rare and highly valued fishing venture with eager youngsters and a quick glance in the review mirror reveals that (for whatever reason) the boat is not there. Years later, you laugh (or not).

Photo by Kirsten Workman, UVM Extension

Farmers are used to getting foiled and generally expect the unexpected: things break, animals get sick, employees don’t show up on time, and weather fails to be optimal. One less common but no less frustrating way that plans can get spoiled is related to pesticide and those bothersome ‘replanting restrictions’ that accompany herbicides. For example, you might want to rotate a corn field to grass for a few years, but you discover that the labels from last year’s herbicide cocktail says you can’t! The herbicide label describes which crops can be planted and when following the application of a particular pesticide. These restrictions are not recommendations, they are the law. Why it is the law may be related to potential harm to subsequent crops caused by persistent herbicide activity, or it may be related to known or unknown issues related to pesticide residues that could make a crop (or milk/meat from animals that ate the crop) unfit for human or livestock consumption.

The simplest questions you can ask to avoid this problem are 1) what do I want to plant in this field next year? 2) Will the herbicide program that I am planning to use this year allow me to proceed as planned? If not, you need to find out a product that will allow you to follow your desired course of action.

The same challenges can occur if you hope to harvest a cover crop (e.g., rye or triticale) as a livestock feed.   Some herbicides used in corn production systems do not allow for planting winter rye or certain other cover crops. While the label is the law, state Agency of Agriculture regulators have legal authority to interpret the label. In regard to this issue, Cary Giguire, of the Vermont Agency of Agriculture has confirmed that cover crops in Vermont CAN be planted even when the rotation/replanting restrictions on the label seem to disallow it — as long as 1) the farmer is willing to accept the possibility that the stand will be reduced due to remaining herbicide activity; and 2) the cover crop will not be fed to livestock. The Vermont Agency of Agriculture essentially considers such a crop to be ‘manure’ and not a crop. If you want the option of feeding the cover crop, you and your custom applicator need to plan to use a weed control program that will keep that option open.

Just recently I was informed of a situation where a farmer wanted to plant a perennial Lumaxgrass/legume mixture into a field that was planted with corn in 2014. The field had been treated with a combination of glyphosate (the active ingredient in Roundup®) and Lumax® the year before. That’s right: foiled again! Bullet points on page 12 of the version of the Lumax® label I have states:

  • ‘Do not rotate to crops other than corn (all types), cotton, small grain cereals, soybeans, sorghum or peanuts the spring following application of Lumax®.
  • For all other crops, wait 18 months.
  • Do not rotate to food or feed crops other than those listed on this label’ (perennial forages were not listed)

It is a very good idea to always ask the custom applicator what the replanting restrictions are and then for you to verify it.  Your custom applicator or consulting agronomist should be able to furnish you with a label and, if asked, mark the relevant sections to address your questions. Verification is recommended not because anybody will try to mislead you, but because we all occasionally forget, misunderstand, and make mistakes. Labels for most agricultural pesticides can be found at . Whether you open them in your web-browser or Adobe, they should be word-searchable, and that should help you find the section of the label that you are interested in. Terminology varies among labels, so use search terms such as ‘rotation,’ ‘replant,’ and ‘restriction.’ If you can’t find it using search terms, make yourself a cup of coffee and read the whole label! Or call your local Extension Agronomist to help you find the appropriate section.

A little due-diligence with herbicide selection can save a lot of time, frustration, and, in some cases, financial loss.

Posted in Uncategorized | Tagged , , , , , , , , | Leave a comment

June 30 Corn Nitrogen Update!

Everyone suspects that there has been a fair amount of leaching of soil nitrate from corn fields in the Northeast this year, but how much?  Since most of the corn is more than 12 inches tall, it is too late to use the pre-sidedress nitrate test (PSNT) on most fields; recommendations are not valid if the samples are taken after that time.  It is not too late to use the Adapt-N program. Recommendations I have seen generated from Adapt-N have ranged from 60 to 150 lb/acre of sidedress nitrogen – – even when a lot of manure was applied and accounted for.  For example, the program shows that local field with soils that are not particularly coarse-textured lost over 56 pounds of N to leaching since June 1.  Some of you may think that is a lot, others may be surprised that more was not lost.  Either way, if the corn is missing 56 pounds of N that it needs, the yield will be affected.  Twenty tons of corn contains 180 pounds of actual nitrogen!

Plant demand for nitrogen is about to skyrocket.  While nitrogen fertilizer can have a positive impact when applied up to tasseling (if you can get in the field), the ideal time to apply sidedress nitrogen is at or before the 10-leaf stage (V10).  If you are putting liquid fertilizer (32% UAN) on corn, it is ideal to use drop hoses/tubes to dribble the fertilizer between the rows to avoid leaf damage.

I strongly believe that recommendations from Adapt-N are superior to those generated by the PSNT, especially in unusual years like this.  It is able to account for nitrogen uptake, loss, and need based on the manure you applied (analysis, date of application, incorporation), planting date, expected yield, hybrid relative maturity, fertilizer already applied, your local weather, and your soil types.  It can also generate a ‘virtual PSNT’; that is, it can predict what the pre-sidedress nitrate test (PSNT) would be if someone had physically taken a sample.  In my experience, this prediction is accurate.  If you really want to get into the details, you can compare the recommendation that the PSNT would have given you with the recommendation that Adapt-N gives you.  Also, if you give the program your email address, it will send you a regular ‘nitrogen status update’ that will help you to understand what is going on in the crop and soils of your fields.

One farm in central Vermont a 25 ton/ac expected corn silage yield recently had a ‘virtual PSNT’ of 7.6 ppm (generated by Adapt-N).  If this level of nitrate were found on an actual PSNT report, the sidedress N recommendation would be 125 lb/ac of actual N.  Because Adapt-N was informed about planting date (in June) and actual and historical weather data, it is giving a sidedress-N recommendation of 150 lb/ac for this field.  This is higher than the PSNT would recommend . . . but it is based on better information.

‘Whoa!  Wait!  I have NEVER applied 150 lb/ac of sidedress nitrogen to my corn.  I have never needed it, and never had a crop failure because I didn’t do it.  I’m not doing it!’  Totally understandable!  It is wise not to depart too far from what you know, and a good idea to verify a practice for several years before adopting it.  If Adapt-N comes up with an uncomfortably large sidedress nitrogen recommendation for your field(s) you can 1) still apply whatever level of sidedress N you are comfortable with, and/or 2) apply a the recommended rate to one or more small, typical, and visible areas of your field; 3) be ready to make further adjustments if the need becomes clear; and 4) do a stalk nitrate test at harvest to see which strategy worked better.

If you are curious about what recommendation Adapt-N would give for your field, please feel free to contact me.  I do have a license for the program and am running recommendations for interested farmers.  My main goal is to teach people how to use it so that they can begin using it themselves.  It really does not take much time.

Daniel Hudson
University of Vermont Extension
Agronomist and Nutrient Management Specialist
374 Emerson Falls Road, Suite 1
St. Johnsbury, VT 05819-9103
Office: (802)751-8307 ext 356
Mobile: 802-535-7922

Posted in Uncategorized | Tagged , , , , , , , , | Leave a comment

Managing to Optimize Your Corn Silage Yield After a Difficult Start

by Daniel Hudson, UVM Extension

Excessive rain has likely caused significant leaching and/or denitrification in corn fields.  Recommendations generated by the pre-sidedress nitrate test (PSNT) are not nearly as useful in years when weather is as far from normal as it has been. This is an excellent year to use Adapt-N to generate data-based sidedress nitrogen recommendations for your corn crop.

The current situation
Decent weather in May allowed for timely planting, but with more than 5.5 inches of rain in the last 30 days, we have reason to wonder about how much nitrogen has been leached out of the root-zone in our corn fields.  With cool temperatures, a fair amount of cloudy weather, and nearly saturated soil conditions, the corn has been treading water.

Low milk prices have us wondering where costs can be cut.  Given the desire for full bunker silos, skimping on nitrogen fertilizer is not usually the first or best impulse.  Given recent unusual weather patterns, this is NOT an ideal year to use the pre-sidedress nitrate test (PSNT) to determine your corn nitrogen fertilizer needs. The PSNT is designed to predict sidedress nitrogen fertilizer needs in fairly normal conditions.  It does accurately measure the amount of nitrate present, but the recommendation is based on the assumption that the present nitrate concentration is a good indicator of future nitrogen release from past manure applications.  In a normal year, that assumption works because there is a typical amount of nitrate being released from decomposing manure in those typical conditions, but when abundant precipitation causes nitrate to be leached from the soil, the PSNT report will often come in very low.  In this situation, the PSNT nitrogen recommendation output basically says, “nitrate concentrations are low now and therefore will also be low in the future: apply a whole bunch of nitrogen fertilizer.”   The PSNT does not know whether or how much manure has been applied to that field over the past several years.  Thus, in the context of unusual weather patterns, it also does not know whether there is much more plant-available nitrogen in the ‘microbial pipeline’ or not and therefore it often over-recommends nitrogen fertilizer – sometimes by a lot.

Is there a better alternative to the PSNT?  Yes, I believe there is.  Adapt-N was developed by soil scientists at Cornell, based on a simple (outwardly) concept: given a certain set of information, nitrogen behavior in the soil can be modeled well enough to give an excellent nitrogen fertilizer recommendation for corn production.  This is roughly analogous to the program that your dairy nutritionist uses to balance a ration – ration balancing programs work because the program has been made and validated by scientists who understand a lot about cow and microbe physiology.  Both processes were validated by researchers using trial-and-error.

You served your plate, why not eat?
If you have gone to the trouble of developing a nutrient management plan, you already have all or most of the information that you need to make the Adapt-N program work.  Think about what factors affect the release of nutrients from manure:

  • Environmental conditions: rainfall and temperature over time.  Adapt-N uses the GPS coordinates of your field to inform the program what your weather has been like.  You do not need to manually enter weather data.
  • How much manure?  When?  Was it incorporated? Percent solids?  Ammonium nitrogen content?  Organic nitrogen content?
  • Soil organic matter? Texture?
  • Relative maturity of the corn variety planted?  Population? Expected yield? Date of planting?

The program takes this and other data to predict how much plant-available nitrogen you have in your soil now.  Taking historical weather data into consideration, it also predicts when and how much more nitrogen will be released from past inputs.  Depending on the settings you choose, Adapt-N will send you email updates that will tell you the current nitrogen status of each field.  If you get a leaching event, you will know.  If you are wondering how much was leached, it can give you a data-based estimate.  If you need to take corrective action, it will tell you.

If you are following your nutrient management plan, ‘your plate has been served.’  All the shopping, chopping, and cooking is basically done.  Going the next step and plugging the information into Adapt-N is the easy part.If the recommendation is extremely different from what you expect and you are concerned about losing yield or spending too much on fertilizer, you don’t have to follow it!   You might follow the recommendation on part of your field to see what happens.  In any case, the recommendation is a high-quality data-based piece of information to take into account when making your final decision.  In my experience, the program works very well and should be in every corn grower’s nutrient management tool box.

If you want to check to see whether the recommendation was on-target or not, you can evaluate the accuracy and efficacy of this product by using the PSNT or the late-season stalk nitrate test.  At any given time, Adapt-N can predict what the PSNT should be; at the end of the season.  If the stalk nitrate concentration is significantly outside of the optimal 700-2000 ppm range just before harvest, then there is reason to believe that either the program did not work or the data that was fed into the program was not correct.  That raises the final point: garbage in, garbage out.  The program can be no better than the data that is fed into it.  If your soil testing procedure was not correct, the soil organic matter numbers that are fed into Adapt-N might be incorrect.  If manure sampling was not done properly, some of the most important program inputs will be based on flawed data.

It is rare for anyone in Extension to promote a particular proprietary product.  My reason for doing so in this context is:

  1. The program was developed and is still being refined by Cornell University researchers.  That is to say that there is solid data that supports the product.
  2. There are no competing products on the market that have demonstrated (at least to me) the ability to do what this program does.   If there were, those products would certainly get equal time from me.  If you know of or are steward of such a program, I would be glad to hear about it.

If you have an up-to-date nutrient management plan and would like this product demonstrated on your farm, please contact me ( and I would be glad to work with you to get nitrogen recommendations on up to three of your corn fields.  If you would like to jump in, the product can be purchased at:

Posted in Uncategorized | Tagged , , , , , , , , , , | Leave a comment

A Virtual Pasture/Plot Tour in Cabot, Vermont

The best time to see a set of forage variety plots is at about the least convenient time of year — right when dairy farmers are trying to take first cut and/or planting corn.  It is not uncommon for someone to say something like, ‘why don’t you take some video of that event so I can see it?’  While some things will clearly be lost, that is not a bad idea.  IMG_0798 The video clips were taken individually and are unscripted and unedited.  No endorsement of any grass or legume variety is intended, despite various comparative terminology that may have been used.

Why Use On-Farm Forage Plots?

As with corn and cow breeding programs, much progress has been made in the forage breeding.  Unfortunately, the seeds of an average-performing variety look mostly like the seeds of a far superior variety.  Differences can only be observed in the field.   I believe that there are opportunities for farmers to increase profitability by choosing forage species and varieties that address various needs on their farm.  Do you hate orchardgrass because it heads out way too early for you to make quality first cut haylage?  Much later-maturing varieties exist!  Do your cows largely reject orchardgrass after the first grazing event?  This is likely due to foliar disease, and disease-resistant varieties of orchardgrass exist.  If you could increase the dry matter intake and lactation of your cows by using haylage made with lower-fiber grasses or grasses with higher fiber digestibility, would it be worth a look?   Are there higher-yielding, more persistent legume species and varieties?  What does it look like when I combine species/variety X, Y, and Z?  What kind of seeding rate is appropriate?  You can read the tech sheets on the varieties available from your local vendor, or you can take a look at them in a setting similar the one on your own farm.  Given that you are going to live with your new seeding for five years or more, which do you think might be more useful?

The FarmIMG_1034

These plots were planted on the [Geordie and Emery] Lynd Farm in Cabot, Vermont in late-August of 2014.  This particular field generally has excellent snow cover.  It is also close enough to the manure pit that it can easily receive liquid manure through an irrigation system.  The video was taken on May 21, 2015 – and was grazed that same evening.

The Equipment

The Carter Plot Seeder that was used to establish the plots in 2014 has what looks like a section of a cultipacker in IMG_0668the front, but which actually serves to open a seed slot.  This ‘culti-opener’ is connected to the crank on the Briggs and Stratton Engine and actually pulls the machine along….unless you are going up-hill, in which case you might need to provide some of the force.  Going down the hill, gravity provides some of the drive, and I provide Flintstone-style braking.  This machine allows many small plots to be established quickly with no need for vacuuming out seed from the previous plot.  Prior to seeding, the field was conventionally prepared and cultipacked.

The Chosen Species and Varieties


First cut perennial ryegrass, May 21, 2015

How did we decide what to plant (or not) in the plots?  Mostly by interacting with seed companies and the farmer.  Seed companies sent small amounts of seed to use in this and other projects.  Understanding that these plots were going to be in Vermont, most of the species and varieties are among the most winter-hardy that they carry, especially the perennial ryegrasses.  We excluded tall fescue from the plot area because it is difficult to get rid of in an organic system and because this field is a pasture for lactating milk cows.  Even the vendors will tell you that even the ‘soft-leafed’ varieties of tall fescue should not be included in dairy pastures, due mainly to the lower palatability, the possibility of lower DM intake, and/or spotty grazing.  Because the farm was organic, we also had to exclude seed that had been treated with banned substances.


Kura clover

A fair number of perennial ryegrasses were included in order to compare winterhardiness (all had excellent winter-survival coming out of the first winter), maturity, yield, and quality.  Very little perennial ryegrass is currently used in Vermont pastures.  It is less persistent, but much later maturing than Kentucky bluegrass.  With good management, yield can be comparable to orchardgrass.  A lot of progress has been made by plant breeders over the past several years and perennial ryegrass deserves a closer look under several management and environmental scenarios.

Meadow fescue was also included because it is re-emerging in the marketplace as a high-quality winter-hardy species and little is known about how it might fit into our dairy forage systems.  Kura clover was included because it can be high-yielding and persistent once it is established.  It is known to be slow to establish, but we want to find out if or how much it needs to be coddled when planted in a pasture mix.  It is said of kura clover that ‘the first year it sleeps, the second year it creeps, and the third year it leaps.’  We shall see…

 The plots

Grazing the Plots

Posted in Uncategorized | Tagged , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Italian Ryegrass as a Companion Crop and Cover Crop

By Daniel Hudson, UVM Extension Agronomist

Click here to see this article in PDF form


Orchardgrass, red clover, and white clover growth 71 days after late-summer seeding. Seeding rates: 10, 8, 4 lb/ac, respectively.


Orchardgrass, red clover, white clover, and Italian ryegrass growth 71 days after late-summer seeding. Seeding rates: 10, 8, 4, 6 lb/ac, respectively.

Challenges associated with establishment-year grass/legume seedings include low forage  yield, high weed yield, and soil erosion. To address these problems, farmers sometimes include a more rapidly-establishing ‘companion’ crop in the seeding mixture. Common species include oats, peas, barley, spring triticale, or some combination thereof. While these species can work very well, the seed is relatively expensive and is best planted through the large grain box of a drill. Italian ryegrass (IRG) is increasingly being used as a companion crop because it can produce higher yields of forage with quality superior to that of oats, the seed is much less expensive, seeding rates are low, and it can easily be metered through the small-seed box with perennial grasses and legumes. Its dense, fibrous root system is also well-suited for soil stabilization and improving soil quality.

Another characteristic of IRG is that it establishes much more rapidly than most forage species. Virginia Tech researchers demonstrated that IRG accumulated three times more dry matter than alfalfa and nearly five times more dry-matter than orchardgrass in the first 30 days. At 51 days, IRG had accumulated 5.6 and 5.3 times more DM than alfalfa and orchardgrass, respectively.   Depending on the circumstances and management, this characteristic vigor can be very helpful (yield) or provide excessive competition.

Potato farmers in Northern Maine often have barley in their crop rotation. Increasingly, when they plant barley they are interseeding it with IRG. Because true IRG does not produce a seedhead in the first year, it does not interfere with barley harvest. After the barley has been harvested, the prolific roots of the IRG scavenge nutrients and add carbon to the soil until it is plowed in the fall. Because highly disturbed soils tend to lose soil organic matter, interseeding IRG in the barley crop is a sensible way to attempt to preserve soil quality.

In an effort to boost yields and improve weed control in perennial forages, an often catastrophic mistake is using an excessive rate of IRG seed as a companion to the IRGCCCC1perennial species in the seed mixture. Doing so can result in a high yield of IRG forage in the first year and reduced yields from the perennial species thereafter.  Recommendations from University of Wisconsin indicate that IRG seed should not be included at more than 2-4 lb/ac when being used as a companion crop.

Research from University of Wisconsin confirm that:

  • When grown as a companion crop, some IRG varieties suppressed alfalfa growth more than others.
  • Excessive shading from IRG or frequent harvest in the first year could be hard on perennial seedlings.
  • In areas with adequate rainfall the ryegrass was more competitive with the alfalfa.
  • Some IRG varieties grown as companion crops yielded more forage DM than an oat companion crop.
  • An IRG companion crop in a perennial forage seeding can increase yields by 1.5 tons/ac compared to perennial forages grown without a companion crop.
  • Treatments with the IRG companion crop had between 0.4 and 1.6 tons/acre less weed biomass than the control that was planted to alfalfa alone.

In addition to adding tonnage to a first-year seeding of perennial forages, Italian ryegrass protein levels are high, fiber levels are low and 30-hr neutral detergent fiber digestibility (NDFd) is extraordinarily high. For more information on growing Italian ryegrass as a forage crop, please see Italian Ryegrass as a Forage Crop.

Unfortunately, its utility as a companion crop does not mean that it is a substitute for cereal rye (i.e., fall/winter rye) in the Northeast U.S. cover crop arena. While it does share many characteristics with cereal rye winter-hardiness is not one of them. If planted prior to September 1 (depending on location), Italian ryegrass can function as a cover crop. Unlike oats, it will not necessarily completely winterkill. Unlike rye, unless temperatures

Second year Italian ryegrass -- significant but not complete winterkill.

Second year Italian ryegrass — significant but not complete winter-kill.

are mild and/or snow cover is substantial, winter survival of Italian ryegrass will be spotty at best. Continued advances in plant breeding may result in varieties of Italian ryegrass that are winter-hardy enough to consistently allow the plants survive the first winter and subsequently complete their biennial lifecycle. Italian ryegrass planted after corn silage will not grow appreciably before winter. If it survives, it will be very slow to rebound in the spring and will provide negligible cover crop service. Future work on cover cropping systems will determine how/when it can be used as an in-season cover crop in corn silage and vegetable production systems.

Companion crop management tip: When using a companion crop of any species, variety, or combination, special attention must be given to the basic needs of perennial seedlings in the understory in order to avoid needing to replant. Both light and water competition from the companion crop can put the perennial species at risk. Excessive and/or prolonged shading of the perennial forage seedlings results in etiolation (few leaves, tall/spindly growth, and a yellow color). Etiolated seedlings are less thrifty, more prone to lodging, and more vulnerable to damage from hoof and tire traffic. Given the high cost of replanting a failed perennial stand, if light competition seems to be approaching a critical threshold at a time that is not convenient for harvesting the companion crop, it is often better to clip the top-growth just above the developing perennial seedlings (tedding it to spread out the residue) rather than wait for harvest. The value of this small yield loss is much lower than the cost of reseeding a stand that failed as a result of excessive light competition from the companion crop.

Posted in Uncategorized | Tagged , , , , , , , , , , , , , , | Leave a comment