Annual cereal forages serve an integral role in integrated crop/livestock production systems across the West. Recently, producers have realized the 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.
There are many advantages of growing annual cereal forages including adaptation to cool climates and higher elevations, they are easy to grow with no special equipment required beyond a grain drill, they are productive in dryland and irrigated systems, they provide good nutritional quality to livestock, and they are effective at disrupting weed and disease pest cycles and rodent problems. 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 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. Additionally, growers send samples to a laboratory to obtain quantitative analyses of nitrate content of cereal forage hay.
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.
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 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, and 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.
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.
- Evaluate nitrate content and forage quality of fall growth of annual cereal forages on five to ten fields per year.
- Compare results of Nitrate QuikTest and Quantofix Nitrate Strip Test to laboratory analyses.
- Evaluate effect of soil moisture on nitrate content of forage.
- Evaluate the effect of frost on nitrate content of forage.
- Evaluate the effect of annual nitrogen fertilizer application on nitrate content of forage.
- Educate producers, Extension faculty, and others regarding the potential for nitrates and forage quality of cereal forage fall growth, accuracy of the Nitrate QuikTest and Quantofix Nitrate Strip test, environmental conditions and management actions impacting nitrate levels, strategies for minimizing risk of economic loss by grazing forages with
- 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.
Fields with annual cereal forage fall growth were sampled in September and October 2017 and 2018. Eight fields were sampled in both 2017 and 2018 with a mix of forage types. Fields included four with straight hay barley; four with alfalfa and a hay barley cover crop; three with alfalfa and orchardgrass, with a hay barley cover crop; one with alfalfa, hay barley, oats, and peas; one with alfalfa, hay barley and oats; one with oats and orchardgrass; one with hay barley, oats, and peas; and one with hay barley, oats, turnips, peas, and radishes.
In each field, 10 locations were chosen randomly to sample forage and to take soil moisture and soil temperature readings. At each of the 10 locations within a field, two separate forage samples were collected, 1) annual cereal forages and 2) all available forage, to create a composite sample of each from the 10 locations. Additionally, at each of the 10 locations, soil moisture was determined using a FieldScout TDR100 Soil Moisture Meter and soil temperature was collected in the top 6 inches of soil.
Other information obtained from the ranchers included annual fertilization regimes, frost events, and irrigation practices for each field.
Forage was evaluated for nitrate (NO3) content using two non-laboratory tests and one laboratory test, including the Nitrate QuikTest (qualitative test, Montana State University), the Qantofix Nitrate Strip Test (quantitative test, University of Georgia), and laboratory analysis (precise quantitative test, Midwest Laboratories). All available forage in each field was also evaluated for nutrient quality.
Regression analysis was used to evaluate relationships among variables.
First year results indicate that the three methods to evaluate nitrates in annual cereal forages were consistent and that forage quality of fall growth of annual cereal forages is good for cattle grazing in the fall.
Nitrate values of annual cereal forages for the Nitrate QuikTest and Quantofix Nitrate Strip Test were positively related to the laboratory test values (P=0.0075 and P=0.0022, respectively). The Nitrate QuikTest and Quantofix Nitrate Strip Test results were positively correlated with the laboratory test (R2=0.79 and R2=0.87,respectively). The percentage of nodes of annual cereal forages with nitrates present using the Nitrate QuikTest ranged from 0 to 40%, with an overall average of 9.6%. Nitrates were detected between 0 ppm and 2,500 ppm with the Quantofix Nitrate Strip Test, averaging 786 across fields. Laboratory analysis for the annual cereal forages ranged from 0.06% NO3 and 0.67% NO3, averaging 0.20 across all fields.
Soil moisture was positively related to the laboratory test (P=0.0999), but soil moisture was weakly correlated with the laboratory test (R2=0.45). Soil moisture in the fields ranged from 16.3% to 41.5% moisture, averaging 29.9%.
Soil temperature was not related to the laboratory test (P=0.6788). Temperatures ranged from 43.4 to 61.3 degrees Fahrenheit.
Available forage across fields averaged 21.0% protein and 71.2% total digestible nutrients (TDN). Protein values ranged from 17.1 in a field of hay barley, peas and oats to 30.0% in a field of alfalfa and hay barley. The lowest TDN value (67.4%) was found in the same hay barley, peas, and oats field with the lowest protein content and the highest TDN value (71.3%) was found in the same alfalfa, hay barley field with the highest protein content.
First year results indicate that the Nitrate QuikTest and Quantofix Nitrate Strip Test are reliable methods to quickly evaluate nitrate content of annual cereal forages when compared to a laboratory test. These methods could be used with confidence in time sensitive situations while waiting for laboratory analyses to be completed. Results also indicate that soil moisture and temperature do not significantly impact nitrate concentrations in fall growth of annual cereal forages. Lastly, results indicate that this forage resource is safe for cattle to graze in the fall and has excellent nutrient quality.
Educational & Outreach Activities
Education and outreach activities have been limited to one-on-one consultations with ranchers that initially agreed to participate int he project, additional discussions with those who had fields that met the project criteria, those that spent time in the fields sampling with me, and a poster presentation at the National Association of County Agriculture Agents (NACAA)in Chattanooga, TN in July 2018. Consultations with ranchers provided an opportunity to engage and discuss their operations, how annual cereal forages fit into their grazing regimes, and how various factors have the potential to affect nitrate quantity in that forage. There is a high level of interest from them regarding the potential for nitrates, the nutrient quality of the forages available in the fall, differences in nitrate and forage quality between species, and additional ways to incorporate annual cereals to reduce production and feed costs.
I presented a poster with first-year results at the NACAA Annual Meeting/Professional Improvement Conference, which is a national meeting of county-based Extension faculty that focus on Agriculture. My poster was one of 11 posters entered into the Research category. This conference gave me the opportunity to talk to professionals from around the country regarding my preliminary results and for all attendees (n=1200) to see the poster and become familiar with the project.
One ranch that participated in the project experienced great gains on calves weaned off of 2-year old cows that were struggling to maintain weight. They weaned the calves to take pressure off the cows and turned the weaned calves into the pasture in late October 2017. These participants originally did not intend to use the pasture, which had a hay barley, peas, oats cover crop planted in the spring, but with the flash drought that hit during late summer of 2017, range resources were limited and of poor quality and they needed a boost for both the cows and the calves.
The rancher reported, “So, the field you sampled, we turned weaned calves out on and they gained, on average, 2.2lbs /day on just the regrowth. (Some did way better than that) There was 34 head there for 24 days and there is still some feed there, but we got busy doing other things and didn’t turn anything else out there. We were very happy with the results, especially since it turned dry and we were able help the young cows out and use the feed when it was ready..”