Evaluating Nitrates and Forage Quality in Fall Regrowth of Annual Cereal Forages

View the project final report

Commodities

• Agronomic: barley, hay, oats, radish (oilseed, daikon, forage), wheat

Practices

• Animal Production: feed/forage, feed management, grazing management, pasture renovation
• Crop Production: cover crops, crop rotation
• Education and Training: demonstration, extension, participatory research, technical assistance, workshop
• Natural Resources/Environment: soil stabilization
• Pest Management: disease vectors
• Production Systems: integrated crop and livestock systems
• Soil Management: soil quality/health

Annual cereal forages serve an integral role in integrated crop/livestock production systems across the West. Historically, cereal forages
were used primarily for livestock feed in disasters during drought, as emergency feed. When this occurs, haying or grazing omits the
opportunity to harvest the cereal for grain, but, likely improves operations’ economic sustainability during challenging situations. More
recently, producers have realized additional values of annual cereal forages in rotational systems when renovating alfalfa, integrating them
into systems to supplement perennial forages, and in cover crop mixes. Cool-season annual cereal forages most widely used in Montana
and across the West include barley, wheat, oats, and triticale.
From 2000 through 2007, an average of 281,000 acres of ‘grain hay’ was planted in Montana(1). While 2008 was the last year Montana
Agriculture Statistics reported grain hay separately, total acreage of cereal hay acreage has steadily grown due to increasing numbers of
cereal forage cultivars available and the utility of the feed(2).
Advantages of growing annual cereal forages include that they are adapted to cool climates and higher elevations, are easy to grow with no
special equipment required beyond a grain drill, are productive in dryland and irrigated systems, provide good nutritional quality to
livestock, and are effective at disrupting weed and disease pest cycles and rodent problems. Montana State University research shows that
dryland and irrigated winter and spring cereals can produce as much as 3.6 tons/acre and provide adequate nutritional quality for winter
maintenance and gain for cattle(3). Cereal forages also provide a great source of energy, which is sometimes limiting in winter rations.
Additionally, winter cereals, specifically, have been shown to produce between 138% and 328% higher yields than alfalfa in dryland
situations and 141% more under irrigation at research sites across Montana(4).
With the myriad benefits of using cool-season annual cereal forages, there are also disadvantages. Primary disadvantages include being
annual crops that require yearly planting and the potential for nitrate accumulation. Nitrates in cereal forages generally peak when cereals
are in the boot stage, however, stressors such as drought, hail, frost, mineral deficiency, prolonged cloudy periods, and herbicide damage
can boost nitrate levels at all stages of growth. Additionally, nitrogen fertilization can increase nitrate levels in these forages.
Nitrates in cereal forages have the potential to cause nitrite poisoning in livestock, which, depending on the severity, can lead to economic
losses due to weight loss, abortion, reduced breeding rates, weak calves, reduced milk production, and animal death. Nitrate content of
cereal forages can be assessed both qualitatively and quantitatively. Montana State University Extension developed the Nitrate “QuickTest”
protocol for qualitatively evaluating nitrate presence with a diphenylamine/sulfuric acid solution(5). Additionally, growers send samples to
a laboratory to obtain quantitative analyses of nitrate content of cereal forage hay.
In recent years, livestock producers have inquired frequently in the fall with Montana State University Extension offices regarding the
nitrate content of cereal grain regrowth, often referred to as volunteer growth. These producers, wishing to capitalize on the new growth,
want to better understand the potential for nitrates, but many have little experience grazing it and approach the situation with caution. In
Park County, six producers, representing nearly 2000 acres of cereal grain hay production, requested 10 qualitative tests on oats, hay
barley, triticale, sudangrass, and barley regrowth in September 2016 alone. Half of these tests, representing approximately 1200 acres of
production (0.5 tons/acre regrowth), had nitrates present. The 1,200,000 pounds of forage that could not be grazed by livestock, coupled
with an average lease rate of $30 per cow-calf pair in Park County, creates an economic loss of $34,890 in grazing loss potential if it forced
the producer to lease pasture elsewhere.
After consulting with three Extension Forage Specialists, it became clear that research regarding the potential for nitrate accumulation in
fall regrowth of cereal forages is unavailable and nutrient quality of the feed is limited. Producers have largely relied on Nitrate QuikTests
to evaluate the safety of using this feed resource in the fall due to its convenience. Additionally, comparisons of the Nitrate QuikTest and
quantitative laboratory analyses do not exist for fall cereal growth. Therefore, the purpose of this study is to evaluate the nitrate content of
cereal growth in the fall, 2) evaluate the forage quality of the available growth, 3) evaluate how environmental conditions and crop
management strategies impact nitrates and forage quality, and 4) evaluate the accuracy of the Nitrate QuikTest on fall cereal growth.
The impetus for this project is derived from information demand from producers on the ground that encounter this situation on their
operations. This participatory research project will allow participating producers to run their operations as they normally would, while
allowing access to fields for data collection. Production practice information will be shared, data will be synthesized to obtain results, and
solutions and actions will be formulated. These solutions and actions can then be shared locally, statewide, regionally, and nationally.
Participating producers represent a geographic cross-section of crop and livestock producers in Park County. All run commercial cow-calf
operations that raise between 300 and 500 cow-calf pairs and retain yearlings. Each operation produces their own hay, which is primarily
alfalfa, and use cereal forages in rotations for alfalfa renovation. One operation produces cereal forages for seed in rotation with alfalfa and
another produces an average of 10,000 bushels of malt barley annually. All of these producers are early adopters of sustainable agricultural
practices.

1. Evaluate nitrate content and forage quality of fall growth of annual cereal forages on five to ten fields per year.
(Sampling: Fall 2017, Fall 2018; Data Synthesis: Winter/Spring 2018, 2019)
• Clip plots of new growth to obtain representative forage samples from each field.
• Qualitatively test nitrates using the Nitrate QuikTest.
• Send forage samples to laboratory for quantitative analysis of nitrates and nutrient quality.
2. Evaluate Nitrate QuikTest and laboratory analyses.
(Sampling: Fall 2017, Fall 2018; Data Synthesis: Winter/Spring 2018, 2019)
• Compare results of quantitative Nitrate QuikTest and qualitative lab analyses.
3. Evaluate effect of soil moisture on nitrate content of forage.
(Sampling: Fall 2017 and Fall 2018; Data Synthesis: Winter/Spring 2018, 2019)
• Measure soil moisture at each plot to evaluate relationships between soil moisture and nitrates.
• Compare nitrates in forage between irrigated and dryland systems.
4. Evaluate the effect of frost on nitrate content of forage.
(Sampling: Fall 2017 and Fall 2018; Data Synthesis: Winter/Spring 2018, 2019)
• Document number of frost events at each plot to evaluate the relationship between frost and nitrates in forage.
• Compare nitrate content of frosted vs. not frosted forage.
5. Evaluate the effect of annual nitrogen fertilizer application on nitrate content of forage.
(Sampling: Fall 2017 and Fall 2018; Data Synthesis: Winter/Spring 2018, 2019)
• Document presence/absence, timing(s), and quantities of nitrogen fertilization in the year each sample is obtained.
• Compare nitrate content of fertilized vs. non-fertilized forage.
6. Educate producers, Extension faculty, and others regarding the potential for nitrates and forage quality of cereal forage fall growth,
accuracy of the Nitrate QuikTest, environmental conditions and management actions impacting nitrate levels, strategies for minimizing risk
of economic loss by grazing forages with unsafe nitrate levels, and animal nutrition considerations.
(Ongoing throughout project)
• Produce a fact sheet describing project goals, objectives, design, and results for distribution to Park County producers and MSU
Extension
faculty.
• Publish project results and successes on the MSU Park County Extension website and Facebook page.
• Present results to producers in Park County and neighboring counties at workshops and field days and MSU Extension faculty at
regional
and statewide meetings.
• Present preliminary and final results at regional/national meetings of relevance.
7. Evaluate change in knowledge, behaviors, and attitudes; producer adoptions of recommended strategies; changes in management by
producers as a result of this information, including the WSARE Program Outreach Survey in the process.
(Fall 2018-Winter 2019)
• Conduct qualitative and quantitative evaluations of educational programs.
• Conduct personal interviews with grant participants and surveys of workshop and field day participants.