- Focus on Agriculture, by Jeff Carter
- News & Events
- Welcome Jonas & Merritt
- NCIS Crop Insurance, by Jake Jacobs
- Knowing Your Nutrient Mass Balance, by Rachel Orr
- Grazing at Islandacres Farm, by Cheryl Cesario [Feature Article]
- Water Quality Financial Analysis, by Tony Kitsos
- Putting a Public Face on the Pursuits of Farming, by Kirsten Workman
- Soil Depth and Nutrient Accumulation, by Kristin Williams
Sign Up – Coming Soon – For Our Fall Grazing Class 2018!
Middlebury, VT October 18, 25, November 1, 8, 2018
Poultney, VT November 27, December 4, 11, 18, 2018
The fee is $40 which includes The Art and Science of Grazing book by Sarah Flack.
- Want to change from confinement or set rotation to management intensive grazing?
- Have a grazing plan, but want to better understand how to implement it?
- Need grazing infrastructure (e.g. fence, water, animal trails) and would like to design a system that may qualify for NRCS financial assistance?
- Pasture nutrition and animal performance
- Carrying capacity, stocking rate vs. density
- System design and infrastructure needs
- Management to avoid overgrazing
- Soil, plant and animal health
- Record keeping
In addition to 4 class dates, there will also be opportunity for one-on-one consultation.
Registration Online Coming July 2018!
For more information or questions, contact Cheryl Cesario- 802-388-4969 ext. 346 or 1-800-956-1125
This program is supported with a grant from:
Focus on Agriculture, by Jeff Carter
News and Events
Remembering Bob Parsons
Managing Agricultural Risk, Jake Jacobs
Welcome Rachel Orr!
SMART Goals and Grants, Cheryl Cesario
The Things You Discover on Your Way to Discovery, Kristin Williams
Nutrient Management is More than Just a Plan, Kirsten Workman
Spring into No-Till Seedings, Nate Severy
Got Questions? Contact Us! 802-388-4969
Don’t miss these two great events. You can RSVP for either or both at
802-388-4969 or firstname.lastname@example.org
Wednesday, August 23rd
Innovation in Action: No-till roller crimper
(A #CleanWaterWeekVT Event)
12:30 – 3:00 PM
Bonaspecta Holsteins | 1133 Jersey Street S., Addison, VT
Click HERE for the flyer
Join the UVM Extension Champlain Valley Crop, Soil and Pasture Team and the Champlain Valley Farmer Coalition for a field day at Bonaspecta Holsteins Farm to see innovative agricultural practices designed to reduce erosion and protect water quality. Come learn more about:
TWO (2) Water Quality Training Credits for farmers!
This event is one in a series of events happening for Clean Water Week.
Free lunch at 12:30 generously sponsored by Seedway. Come join the fun!
Thursday, August 31st
2017 Short Season Corn Hybrid Field Day11:00 AM – 2:00 PM
Vorsteveld Farm | 3925 Panton Road, Panton, VT (just across the street from the telephone building, next to the new solar panel installation)
Click HERE for the flyer
Join the UVM Extension’s Champlain Valley Crop, Soil & Pasture Team and local seed suppliers in the field to see our corn hybrid demonstration, comparing shorter season corn varieties (85-98 day). Can we accomplish high yielding corn and timely cover crop seeding? Come check it out. We’ll take a trip down the road and check out some long season hybrids too! Research in northern VT has suggested that variety, as opposed to just day length, is important in determining corn yield. To this end, we have planted 21 corn hybrids ranging from 85 DRM to 98 DRM to assess yield and quality. The objective is to test varieties on our soils and find optimum day length so that there is more time in the fall for cover crop seeding and establishment without sacrificing yield. We will also have the opportunity after lunch to look at some longer day hybrids in a different field and take a look at this farms novel approach to no-till, manure application and cover cropping.
By Kristin Williams, Agronomy Outreach Professional
We just finished a two-year, multi-farm study on the health of clay soils, funded through a VT Conservation Innovation Grant through the NRCS. Measures of soil health (using Cornell’s soil health test) were not consistent, and we found that comparing practices over time was more informative than comparing field to field. One interesting, and maybe
obvious, lesson was the correlation between soil health practices and crop yields.
So, how do soil health practices influence yield? Research suggests soil health can improve yields. It is important to note our project focused on demonstration, not replicated research. We compared no-till and conventional/reduced till corn silage on 5 farms with clay fields in our region. A simple t-test revealed no significant difference in yield between no-till (19.1 tons/acre) and conventional (19.2 tons/acre). More importantly, we were able to demonstrate that a farmer can grow no-till without yield losses, and be successful with good management practices. A yield gain might take time as the soil builds up its condition.
We also wondered how cover crop species or mixes might affect corn silage yield. We had an opportunity to use a field where the corn was accidentally killed. We planted 15 different combinations, including 4 single species, 6 two-way mixes, and 5 three-way mixes. This project was a slight anomaly in that the cover crops were planted with a drill in late August, which allowed for a more vigorous production of all cover crops. Radish was a star in the fall, maximizing both phosphorus and nitrogen uptake. We did not measure phosphorus content in the spring, so we do not know how much was retained in the soil. It seems to have allowed
for more available nitrogen in the soil at the time of a pre-sidedress nitrogen test (PSNT), therefore requiring less nitrogen. Surprisingly, legume mix covers had good fall biomass, but that did not translate into more N mineralization.
We applied nitrogen to each plot as per the PSNT recommendation for 20 tons/acre corn silage. At the end of the season, we measured corn silage
yield and compared that to nitrogen applied (see graph). The winter rye plot had a lower corn silage yield and required more nitrogen. Other than the nutrient effect of less uptake and slower decomposition, there may have been a physical barrier created by the standing rye crop, which was particularly vigorous in the spring. However, our three-way mix (winter rye – oats – radish) actually had the highest average corn silage yield, even though it required more N at PSNT time than the pure radish stand.
So, do not go abandoning your winter rye just yet. In fact, we think this three-way mix has promise and we are looking for a mix that gives both fall and spring soil conservation. Radish alone will winter kill, which may be good for mineralization, but not as good for spring soil conservation. Oats also winter kill but provide faster fall soil cover than rye by itself.
When using an over-wintering cover crop, it is clear that timing and success of termination is critical for subsequent crop yields. Nitrogen mineralization may happen later in the season with a plant such as winter rye that has a heavier carbon content. In a no-till system particularly, you may need to adjust your nitrogen rates/timing and put more on upfront. If you are using cover crops, a PSNT seems like a wise investment.
It is also important to remember that soil health is a long game, and it may take time to see the results of your labors with cover crops. We have replicated this project by replanting these cover crops in the fall of 2016, this time planted in September, and will look at this again this coming season.
More info about UVM’s PSNT test can be found at:
Focus on Agriculture in the Champlain Valley and Beyond
By Jeff Carter, UVM Ext. Agronomist
Champlain Valley Crop, Soil & Pasture Team Leader
We all have learned a lot about using no-till and cover crop farming practices on clay soils over the past few years, and feel good about it because improving soil health for the future really is important. If not, I don’t think you would be farming.
But the fabric of agriculture is a bit tricky as one side pulls the covers off the other, then back, and over and over. Field practices to improve crop yields and water infiltration come back to bite us with reports of fear that this will increase the amount of dissolved phosphorus in the soil, which is exactly what you want for better crops, but not if it leaks out and pollutes Lake Champlain. Now the quilt comes off again and it becomes apparent that the environmental damage may be increased by activities like improving soil health with tile drainage, no-till planting, even cover crop roots that go down into the soil to reduce compaction. All are field practices we promote with confidence that this will solve the “problem”.
Now in a recent report from Farm Journal, Field Agronomist Ken Ferrie discusses how improving soil health increases the concerns about nitrate and water-soluble phosphorus losses down through the soil. But let’s not stop with that part of the equation. This is not a bad thing; it’s just that now farmers need to be even more aware of how their field management practices impact their P losses. And how important the work we do at Extension to compare different cropping system components helps farmers decide what balance of tillage and crop types is right for their farm. One response is to stop if we are afraid; the other is to carefully move ahead with calculated confidence that we are making a positive difference, measure the effect, recognize some new problems, and move ahead.
The Required Agriculture Practices are now here, and we will have a lot of “quilt pulling” as changing one thing like – requiring buffers along ditches – may trigger responses that are counter-productive like installing tile in the whole field and burying those ditches. Which way is better? I’m not sure; just that when the quilt gets pulled off me, I pull back. Switching to no-till corn is a proven way to help soil aggregate structure, greatly reduce soil erosion and reduce fossil fuel use. Yet the reaction is that preferential flow paths through the soil form as a conduit to move manure and P too fast through the soil matrix.
The Vermont Tile Drainage Advisory Group report has been submitted to the Agencies of Agriculture and Natural Resources, and will inform the Secretaries for their joint report to the legislature in January. I participated on that advisory group and the discussions highlighted that these issues are not simply good and bad. Every action, like improving soil drainage, forces a conflict between a current farm business and family sustainability, and the cost of water quality remediation for past indiscretions in our lake that we are faced with fixing.
The only way that we will be able to keep a reasonable perspective is for everyone (both sides of the bed) to continue to be vigilant to maintain a good balance of using our land resources to make money, but keep the water clean. This will never end, as the challenges of farming in Vermont are made more difficult with awareness of how a little P makes such a big problem in the Lake.
I heard a great quote: “there are no wrong turns on the journey, just course corrections when we figure out where we want to go next.” I think we should be focused on learning how to make the best next moves, together, for farming practices that will help us meet the P reduction goals of the Vermont Clean Water Act. I don’t agree with the folks who want to curtail the dairy industry in Vermont with hopes that a different farming model or land use is better. Get active in your local farmer watershed group (there are three in Vt.), come to conferences and workshops we offer to get better at these decisions, speak up so the general public and legislative policy makers hear your voice.
Have a question for Jeff? He can be reached at 802-388-4969 ext. 332 or email@example.com
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A pdf version of our entire newsletter can be viewed here. Our team work is funded through multiple grants and could not be accomplished without our supporters and funders.
Individual newsletter articles can be viewed on the blog below.
UVM Ext. Agronomy Outreach Professional
As farmers, nutrient management planners and soil conservationists, many of us deal with the estimated loss of soil from fields. We often use a very important tool called the Revised Universal Soil Loss Equation (commonly referred to as RUSLE2). If you have a nutrient management plan, you know about RUSLE2. This tool, however, only estimates soil loss in the form of sheet and/or rill erosion. This is the gradual and sometimes unnoticeable erosion that sheets off fields or that forms small, uniformly spaced and sized channels (less than 4 inches deep). With proper crop rotations, reduced tillage, good cover cropping, good organic matter and even proper manure applications, we can manage for this erosion fairly simply and inexpensively.
Gullies, on the other hand, are the “unaccounted for” erosion that can have a major impact on soil loss, soil health, water quality, and crop yields. Gullies are water formations with increased intensity to sheet and rill erosion, and can also exacerbate sheet/rill erosion. While we have all seen photos of giant gullies big enough to consume a tractor, those tend to be rare. However, the gullies in Vermont farm fields are no less impactful on our landscape. According to an older, but interesting analysis from USDA-NRCS in 1997, they estimated that (19 years ago), roughly 6.1 tons/acre of soil loss per year was attributed to gully erosion, making up roughly 58% of the total sediment lost through water erosion annually (the remaining 4.5 tons/acre/year was from sheet and rill erosion).
Types of Gullies
Ephemeral gullies recur in the same area each time they form, can be partially or totally erased or filled in with tillage, and frequently form in well-defined depressions or natural drainage in a field. As described by the USDA –NRCS (1997), “most ephemeral gullies occur on fields with highly erodible soils, little or no crop residue cover or where crop harvest disturbs the soil.” They are associated with water flow in areas where runoff is great, including snow-melt runoff like that experienced in the Northeast.
True or ‘classic’ gullies are “channels too deep for normal tillage operations to erase.” (NRCS, 2015). They may get bigger in subsequent years, but can also stabilize and become more permanent drainage channels. They tend to start as ephemeral gullies that were left untreated. They can also start as a result of tillage, for example adjacent to a dead furrow. Or they may start at the edges of established grassed waterways or buffers that were inadequately sized or not maintained.
In this pictured example, a gully started upland as an ephemeral gully, but when it reached a dead furrow, this larger scale channel formed. You can see how quickly a gully like this can be an even more significant contributor of soil loss than typical sheet and rill erosion. Depending on how the field is managed a gully like this can account for two to four times the sheet and rill erosion from an entire 25-acre field. It’s hard to tell, but in the picture you can see the field had been cover cropped and no-till planted to corn, but it was too late to prevent the ultimate result. This gully has subsequently been repaired and now has a diversion at the upland slope to prevent its reoccurrence.
This type of significant erosion has many costs associated with it: water quality degradation, decreased yields, and the sometimes significant costs to repair (potentially tens of thousands of dollars). The cost of fixing and maintaining an area where a classic gully has formed can be drastically more expensive and time intensive than preventing them from forming. Once a gully begins forming, additional measures will need to be implemented. Continuing to till and level out an ephemeral gully every year only introduces more soil into the drainage area for erosion.
Conservation practices to prevent gullies include grassed waterways, cover crops, crop rotation and no-till. These practices relate to not re-tilling the gully area, maintaining residue on the soil surface, keeping soil covered and preventing erosion from starting in the first place.
Grassed Waterways are constructed channels that are planted with fast growing grass species that are mowed regularly to reduce sedimentation. These waterways convey the water to a stable outlet where it will not cause erosion. They not only significantly reduce erosion, but are located in the areas of the field where drainage wants to occur anyway and tend to not be very productive. Once installed, they can be permanent with proper maintenance.
Conservation Crop Rotation is a management practice that simply changes the rotation pattern of the field in question. In dairy forage systems this includes reducing the number of years of corn production, and rotating into a perennial sod.
Cover Crops are close growing crops (grasses, legumes, forbs) planted to provide protection from soil erosion on annually cropped fields in the times between cash crop growth. In addition to other conservation benefits, they provide significant decrease in erosion.
No-Till otherwise known as Residue Management is the limiting or elimination of soil disturbance to maintain plant residues on the soil surface all year. By not tilling, soil is not exposed to erosion and it is more stable and able to infiltrate more water and support equipment operations without disturbance. In conjunction with cover cropping, it may eliminate the need for grassed waterways or other more expensive conservation practices, if the gully erosion has not already become a serious problem.
An existing classic gully will need repair. This is a big ticket item. It often requires significant machine time, may need stone or pipe, and often includes a water diversion structure to prevent it from forming again. These can cost more than $20,000 per gully to repair.
Gully erosion is the not so hidden, but unaccounted for, source of erosion in our watersheds. It is detrimental to our waterways, our cropland and pastures, and the sustainability of our farms. Take an afternoon and take a look around your fields. Do you see any gullies forming? Do you see where gullies could potentially form? See a gully in need of repair? Visit your local NRCS office and get help, either stopping gullies before they start or fixing existing gully problems.
+ Estimations based on field observations and NRCS erosion calculations based on dimensions, frequency and soil type.
America’s Private Land. A Geography of Hope, United States Department of Agriculture—Natural Resources Conservation Service, Washington, DC (1997), p. 39 (https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_012458.pdf)
Gordon, Lee M., et al. Modeling long-term soil losses on agricultural fields due to ephemeral gully erosion, Journal of Soil and Water Conservation, Volume 63, Issue 4, 1 July 2008, Pages 173-181.
Poesen, J., et al., Gully erosion and environmental change: importance and research needs, CATENA, Volume 50, Issues 2–4, 1 January 2003, Pages 91-133.
Valentin, C., J. Poesen, Yong Li, Gully erosion: Impacts, factors and control, CATENA, Volume 63, Issues 2–3, 31 October 2005, Pages 132-153.
USDA-NRCS Wisconsin Field Office Technical Guide, Section 1-General Resource References. Ephemeral and Classic Gully Erosion Worksheet. August 2015 (https://efotg.sc.egov.usda.gov/references/public/WI/Gully_Erosion_Prediction.pdf)
USDA-NRCS Vermont Field Office Technical Guide, Section 4 – Conservation Practices.
Do you have questions about soil conservation practices? Would you like to conduct a trial on your farm? Contact Kirsten [802-388-4969 ext. 347, firstname.lastname@example.org]
UVM Ext. Agronomy Outreach Professional
While recently attending a Certified Crop Adviser Conference in NY I started doodling Venn diagrams of the information I was digesting. In the world of soil health, the ‘classic’ Venn diagram is Chemical-Biological-Physical properties all interacting and collectively leading to the ever elusive thing we call soil health. Thinking larger, we can ask the question, does soil health always lead to environmental health? Notably for us, does soil health always lead to a reduction in phosphorus loading to water bodies? And from the agricultural perspective, does soil health always lead what I am terming farm health? What I mean is agricultural productivity and sustainability, including economic realities and crop yields. If we add more organic matter, will we always get greater crop yields? If we increase infiltration, will we always get reductions in phosphorus loss? We’d like to think so, but unfortunately for us reality is complex. Along with this Venn diagram is the overlap. Things take time and teasing out these realities to make sound management recommendations can be tricky and confusing. We continue to use a combination of research and demonstration trials in an attempt to approach that perfect union where farms are building their soil quality, increasing their farm profitability and having more positive environmental impacts.
The Possible Use of Gypsum Amendments to Reduce Soluble Phosphorus
Currently on the market are a number of products being sold both for increasing soil health and better utilization of phosphorus. One demonstration project we began this fall in McKenzie Brook watershed is looking at the use of gypsum amendments to increase soil health while also reducing soluble phosphorus loss. Gypsum (calcium sulfate dehydrate) actually has a long standing history as an amendment, as a source of sulfur and calcium (without a pH change). The NRCS has a practice standard for gypsum application to improve physical and chemical properties of the soil, improve water infiltration, reduce dissolved P in surface runoff and subsurface drainage, ameliorate subsoil aluminum toxicity, and reduce potential transport of pathogens in cases of manure and biosolid application. Utilization of this practice is more common in other parts of the US and applied in bioswales. Science research thus far has primarily focused on flue gas gypsum (FGD) and results suggest there is some efficacy in improving soil health and reducing P loss, but the magnitude of effects may vary.
Sulfur is required for protein synthesis and nitrogen fixation, so in theory, additions of gypsum could increase yield potential if sulfur is limiting in the soil. Calcium is also needed in cell wall and membrane function, growth and fruit development. Perhaps even more importantly, calcium can help improve soil structure as a flocculating agent; that is, calcium can help with soil aggregation via its role as a positively charged ion (Ca2+) held by soil’s negatively charged exchange sites (CEC). It has a stronger bond than other lower charge particles like sodium (Na+), which is why gypsum amendments are used in reclaiming sodic and saline soils. This feature is also particularly relevant to our clay soils if soil aggregate stability and infiltration is poor. Gypsum can theoretically reduce phosphorus loss by two related means. The first is by increasing soil aggregation and therefore decreasing the loss of P with sediment. The second is that calcium-phosphorus complexes can form, keeping the P in a less soluble form. We have begun a demonstration project in McKenzie Brook utilizing multiple types of gypsum in contrast to a short paper fiber lime product, and hope to build upon it next year. We will have more on this topic as this project evolves.
Questions for Kristin? [802-388-4969 ext 338, email@example.com]
UVM Extension Agronomy Outreach Professional (Grazing Specialist)
In March 2016 a concerning milestone was reached: global levels of atmospheric carbon dioxide passed 400 parts per million (ppm). For reference, 350 ppm is recognized as the level which is needed for a healthy functioning planet.
Carbon dioxide is a heat-trapping gas, which is released through human activities such as deforestation and burning fossil fuels, along with natural processes such as respiration and volcanic eruptions. Its increasing levels is one major driver of global climate change.
In November, Architect William McDonough, who specializes in sustainable development, published an article titled, “Carbon is Not the Enemy” in the journal Nature. In it he suggests we can work with carbon in all its forms, to keep it in the right place. Climate change, he says, is “the result of breakdowns in the carbon cycle caused by us, it is a design failure. Anthropogenic greenhouse gases in the atmosphere make airborne carbon a material in the wrong place, at the wrong dose and for the wrong duration.”
A healthy carbon cycle supports life, rather than endangering it. McDonough writes that the way to work with the carbon cycle to preserve and enhance the benefits it provides starts with the soil. A healthy soil can sequester carbon, converting it to a stable form which improves its fertility and ability to hold water.
Dr. Christine Jones, an Australian soil ecologist who was highlighted in the book Cows Save the Planet, describes this process. Plants convert carbon dioxide into sugars or “liquid carbon” which is used for plant growth and is exuded by the roots to feed soil microbes. The plants obtain minerals and trace elements otherwise unavailable to them and in turn, the microbes use the sugars to create stable carbon, including humus. Dr. Jones states that much of the world’s grazing land is losing carbon due to overgrazing practices. However, she writes about the potential to sequester carbon and reduce atmospheric CO2 levels through management changes to improve soil health and activate the “liquid carbon” pathways. There is an enormous potential for the world’s grasslands to capture and sequester carbon and perhaps lower atmospheric carbon dioxide levels.
In a 2014 paper titled “Regenerative Organic Agriculture and Climate Change”, The Rodale Institute states that farming practices that maximize carbon fixation and minimize carbon loss have the potential to sequester more than 100% of current annual carbon dioxide emissions. However, to achieve this, a holistic systems approach to agriculture is needed worldwide that builds soil health by adopting cover crops, crop rotations, and conservation tillage practices.
Currently, The Savory Institute, co-founded by Holistic Management author and educator Allan Savory, is working to promote the importance of livestock in carbon sequestration and bring that message to the consumers. Well-managed pasture, acting as a giant solar panel, captures solar energy, grows dense stands of grasses, keeps soil protected, sequesters carbon and turns this solar energy into animal products. The institute will unveil a “Land to Market” program early in 2017 with a third party seal on qualifying products to indicate that sourcing is regenerative on the land on which it is produced.
Rodale describes regenerative agriculture as “beyond sustainable” – a system built on improving resources, through continual on-farm innovation for environmental, economic and social wellbeing. It is a model we will no doubt be hearing a lot more of as it may prove integral to climate stabilization solutions.
Sources and Additional Reading:
‘Carbon is Not The Enemy’. William McDonough. Nature. November 14, 2016. http://www.nature.com/news/carbon-is-not-the-enemy-1.20976?WT.mc_id=TWT_NatureNews
Cows Save the Planet. Judith D. Schwartz. Chelsea Green Publishing. 2013.
‘Regenerative Organic Agriculture and Climate Change’. Rodale Institute. 2014. http://rodaleinstitute.org/assets/WhitePaper.pdf
‘Meat, the unlikely climate hero?’. Bill Giebler. New Hope Network. November 3, 2016. http://www.newhope.com/news/meat-unlikely-climate-hero
Have a grazing question? Contact Cheryl [firstname.lastname@example.org, 802-388-4969 ext. 346]
By Rico Balzano
UVM Ext. Agronomy Outreach Professional
There is growing consensus that cover crops have many environmental and agronomic benefits including reducing soil erosion, adding valuable organic matter, and improving overall soil health. But how do cover crops fit into a weed control program? And how may they effect other soil-borne pests and diseases?
In 2015, I received a SARE farmer grant to explore the use of mustard cover crops to help control plant parasitic nematodes*, weeds, and soil-borne diseases. Varieties of two species of mustard (Sinapis alba and Brassica juncea) have been identified as producing chemical compounds known as glucosinolates that have been shown to reduce fungus and nematodes populations when mowed and incorporated into the soil. This process is known as biofumigation.
Six varieties of mustard were trialed to test glucosinolate production and overall biomass yield. The yields were measured by weighing samples in the field, and glucosinolates were measured by a lab at the University of Idaho. The varieties were: Kodiak (Brassica juncea), Pacific Gold (Brassica juncea), Ida Gold (Sinapis alba), Caliente 119 (S.alba and B. juncea blend), Caliente 199 (S.alba and B. juncea blend), and Nemat (Eruca sativa– also a Brassica, bred as a nematode trap crop). They were planted in the spring of 2015 and allowed to grow for 60 days before incorporation and measurements were taken. It was found that ‘Caliente 199’ had the highest biomass yield and highest levels of the glucosinolate sinigrin, a volatile compound that has been shown to have anti-fungal and anti-nematode properties. Interestingly, ‘Ida Gold’ contained another gluscosinolate, sinalbin. This non-volatile compound has shown the ability to inhibit weed seed germination. Unlike Although measurements were not taken, it was observed there was less overall weed pressure in the ‘Ida Gold’ plots. This is similar to observations in trials of ’tillage radish’, another Brassica species. It was not determined whether weed suppression was a result of biofumigation or a dense cover crop outcompeting weeds. Planting rate (density) in other cover crops such as winter rye and oats has been shown to effectively suppress weeds. Further study is needed to determine how planting rates of mustards and other Brassica species effect glucosinolate production, disease suppression, and weed control.
As with any biological control, results can be variable. In trials in Idaho, higher soil moisture improved fungus and nematode suppression, while increasing weed pressure. It is necessary to macerate and incorporate the mustard plants for the glucosinolates to be effective. This can be accomplished by mowing and disking in the plants. For fall planted mustards and Brassicas, freezing and thawing may effectively macerate and release the glucosinolate sinalbin, potentially explaining weed suppression the following spring. Further study is needed to determine how these bio-chemicals and cover crops perform under different management.
*Not all nematodes are detrimental. Many play an important role in soil ecology.
Questions about using mustard cover crops? Contact Rico Balzano [802-388-4969 ext. 338, email@example.com]