Final Report for LNC98-135
Dryland and irrigated annual forage trials were conducted over two years to update forage production and quality characteristics for the Central High Plains region. Spring triticale, barley, oat and field pea cultivars were tested at Sidney, NE (elevation 4300 ft above sea level). Winter triticale and wheat cultivars were tested at Sidney, McCook and Mead, NE. Soybean cultivars were tested at Archer, WY (elevation 6000 ft). Summer annual forages tested under dryland at Sidney and/or irrigated management systems at Scottsbluff (elevation 4000 ft) included as many as 9 forage sorghum, 6 sorghum x sudangrass, 1 sudangrass, 3 pearl millet and 9 foxtail millet cultivars. A single cut harvest system was used for both dryland and irrigated forages planted with a double disc grain drill in 6 row plots with 12 inches between rows. A plot swather was used for harvest after most cultivars had headed. Samples were taken immediately after chopping for drying for laboratory feed quality tests.
Winter triticale cultivars yielded an average of 6400 lb of dry matter per acre at Sidney compared to 5200 lb for winter wheat. A triticale cultivar also had the highest yield (4900 lb) among spring forages. Dryland summer forages other than the foxtail millets had an average dry matter yield of 5490 lb per acre over two years at Sidney while irrigated cultivars other than the foxtail millets averaged 12,120 lb per acre at Scottsbluff. Irrigated foxtail millet yields averaged 6490 lb per acre at Scottsbluff for the same years, and dryland foxtail millet yields of 4 cultivars averaged 3060 lb per acre at Sidney for 1997 and 1999. Yields of field pea cultivars in 1998 and 1999 and soybean cultivars in 1999 generally averaged less than 1.5 tons of dry matter per acre.
Forage quality tests were conducted for crude protein, nitrate nitrogen, in vitro dry matter digestibility, neutral detergent fiber, acid detergent fiber and acid detergent lignin. For dryland summer annual forages, the average crude protein content in 1999 was about half that for 1998. The main differences between years were less favorable total amount and timeliness of rainfall in 1999 along with less fertilizer applied. Nitrate nitrogen levels were generally not a problem except for irrigated foxtail and pearl millets where levels approached or exceeded 2000 ppm which is often used as a threshold for toxicity concerns. This problem could likely be controlled by regulating the amount of nitrogen fertilizer applied to these crops. Laboratory determinations indicated that some of the brown midrib (BMR) cultivars in the forage sorghum or sorghum x sudangrass hybrids had the lowest acid detergent lignin fiber levels and the highest dry matter digestibilities, thus making more forage energy available to support animal performance. Mineral levels were determined in 1999 samples for use in formulating animal diets.
The objectives of this project were
(1) interact with farmer cooperators to evaluate the role of annual forages for whole-farm sustainability;
(2) evaluate yield and nutrient determinations on selected annual forage varieties;
(3) create a protein degradability database on annual forages for beef ration formulation/evaluation with the new metabolizable protein system; and
(4) monitor potential concerns for annual forage production, such as pest problems, soil water status and forage nitrate levels.
The lack of published information on forage yields and feed quality for currently available annual forage cultivars led to the proposal to grow such cultivars, as well as those considered standards, in replicated plots so that a database could be developed for researchers, extension personnel and producers to use. Cooperation from agronomists was vital to the planning and conducting of these trials. One of those agronomists was Dr. Ken Vogel, USDA Forage Research Geneticist in Lincoln, who offered to do laboratory analyses as a means of addressing the lack of information on annual forages. He and coworkers had started a two-year project looking at forage yields and feed quality for winter wheat and triticale cultivars in 1997, and offered to contribute the results to the annual forage database. All of the other trials began in 1998.
Annual forage cultivars for a two-year study were requested from seed suppliers, seed companies, and farmers interested in cultivars appropriate for the Central High Plains. Spring triticale, barley, oat and field pea cultivars were tested at the University of Nebraska High Plains Ag Lab near Sidney, NE (elevation 4300 ft above sea level). Winter wheat and triticale cultivars were tested at Sidney, McCook and Mead, NE. Soybean cultivars were tested at the University of Wyoming location near Archer, WY (elevation 6000 ft). Summer annual forages tested under dryland at Sidney and/or irrigated management systems at Scottsbluff (elevation 4000 ft) included as many as 9 forage sorghum, 6 sorghum x sudangrass, 1 sudangrass, 3 pearl millet and 9 foxtail millet cultivars. A single cut harvest system was used for both dryland and irrigated forages planted with a double disc grain drill in 6 row plots with 12 inches between rows. A plot swather was used for harvest after most cultivars had headed. Samples were taken immdiately after chopping for drying for laboratory feed quality tests.
Forage samples were also collected from several on-farm demonstrations involving annual forages to see how results compared with the university trials. Cooperators were identified with the help of Extension Educators in the region. In addition to samples which were dried for lab analyses, additional fresh samples were taken from selected university trials for quick freezing and subsequent freeze drying required for the determination of protein degradability in the rumen. This determination was completed in the Ruminant Nutrition Laboratory of the University of Nebraska Department of Animal Science in Lincoln. The results of lab analyses on forages harvested in 1999 were not available from the USDA and the Department of Animal Science labs in Lincoln until July, August and September, 2000.
Objective 1: Interact with farmer cooperators
When the project began in the spring of 1998, Jerry McRoberts, a farmer and rancher in Cheyenne and Morrill Counties in Nebraska, was consulted in regard to spring triticale cultivars to plant, since he had been searching for and trying cultivars that would yield well in the region. Seed for two triticale cultivars was obtained from him for the research trials. He also had some winter and spring triticale forages growing in the spring of 1998, and samples were taken from his fields for yield estimates and laboratory forage quality analyses. Results were included in the 1998 progress report discussed with producer groups such as the High Plains Ag Lab Advisory Committee. His use of higher nitrogen fertilizer applications than those used in the university trials supported higher crude protein levels than those reported in the university data.
Interactions occurred on demonstrations with a delayed maturity cultivar of pearl millet called Mega Mil. It generally would not produce a seed head in the area environment and therefore remain in a vegetative state. Demonstrations were conducted with strips of Mega Mil planted by Dean Jurgens in Cheyenne County, NE, Bryce Halstead in Kimball County, NE, Norris Harms in Phillips County, CO, and Jack Cecil in Goshen County, WY. Results were mixed. Jurgens grew a productive forage crop but Halstead had a stunted crop in a drouthy high pH soil and a low protein content. Harms and Cecil had trouble getting stands although Cecil was successful in a second year with irrigation and chopped the strip of Mega Mil along with nearby corn for silage, since it had grown as tall as the corn.
Arvika field pea forage being grown by Jerry McRoberts was sampled for yield estimates and laboratory quality analyses. Three samples taken in the early bloom stage of maturity averaged about 23% crude protein in the dry matter, indicating that field pea forage should be very competitive with alfalfa in feed quality. Dry matter yields, however, were disappointing.
The dryland and irrigated summer annual trials at university locations in 1998 and 1999 showed that brown midrib (BMR) sorghum or sorghum x sudangrass hybrids were lower in lignin fiber contents and higher in dry matter digestibilities, which supports limited observations of improved animal performance on these hybrids because of increased energy availability. Interactions with Jerry McRoberts in Cheyenne County, NE, Alton Lerwick in Scotts Bluff County, NE and David Kaufman with operations in western Nebraska and eastern Wyoming led to their decisions to plant substantial acreages of BMR cultivars of sorghum x sudangrass hybrid in the summer of 2000. Photos of these acreages are included in this final report, and the Lerwick photos demonstrate the improved whole farm sustainability achieved when a half circle of pivot irrigated annual forage was available to keep cows and calves in good body condition while forage production in adjacent permanent dryland pasture had ceased and virtually nothing was left for animals to eat. While dryland production of annual forages would be reduced in dry years, the photos from the McRoberts and Kaufman operations show that enough annual forage can be produced in substantial acreages to be a life saver when permanent pastures are bone dry like they were in many parts of the region in 2000.
Interactions with other regional farmers about annual forages took place in 1998, 1999, and 2000. For example, Joe McNurlin in Cheyenne County, NE, has been growing a sorghum x sudangrass cultivar that produced excellent yields. He had the forage tested for feed quality at a commercial lab and then asked for suggested rations using this forage and other forages produced on his farm for growing beef calves. The forage analysis results were plugged into a computer program to provide cattle breakeven projections and ration alternatives to help his farm be more sustainable economically.
Objective 2: Evaluate yield and nutrient determinations on selected annual forage varieties.
A summary of the final results of forage trials is enclosed, titled "Annual Forages for the Central High Plains". This was presented at and included in the proceedings of the High Plains Dryland Cropping Systems Workshops at Goodland, KS, on December 5 and Sidney, NE, on December 6, 2000. These workshops were sponsored by Cooperative Extension in Kansas, Colorado, Wyoming and Nebraska, and attended by agricultural agency and industry representatives as well as producers in the region. Progress reports were discussed and distributed at field days of the University of Nebraska in 1998 and 1999. Selected results were published in the Business Farmer, a regional ag weekly publication and included in the 2001 Nebraska Beef Report which was released by the UNL Department of Animal Science in November of 2000. A progress report was also presented at and included in the Proceedings of the American Forage and Grasslands Council annual meeting held in July, 2000 at Madison, WI.
Conclusions presented to attendees at the December 5 and 6 workshops at Goodland, KS and Sidney, NE were:
(1) The surprisingly large decrease in crude protein contents of dryland summer annual forages grown at Sidney in 1999 vs. 1998 were apparently due to decreased total amounts and timeliness of rainfall in 1999, along with less fertilizer applied in 1999. Since dryland production varies greatly on the High Plains due to climatic variations, it seems prudent for producers to carry out a routine forage testing program to avoid the potentially serious errors in formulating diets with these forages when average nutrient values are used.
(2) Nitrate nitrogen levels in the summer annual forages were generally below the 2000 ppm level often used by animal scientists and veterinarians as a threshold for initial toxicity concerns for animals that consume this forage. However, irrigated foxtail and pearl millet forages had levels that approached or exceeded this threshold, and therefore the amounts of nitrogen fertilizer applied should be less than the levels used in this study. If there is any concern about the nitrate levels in any of the grass type annual forages, the prudent response would be to get forage samples tested for nitrates, so that precautionary feeding methods such as slow acclimation to higher nitrate forages and dilution with lower nitrate forages can be initiated.
(3) Lower lignin fiber levels and associated increases in forage dry matter digestibilities for the brown midrib (BMR) sorghum and sorghum x sudangrass hybrids bring new opportunities for improved animal performance, which has been demonstrated to a limited extent by university feeding trials, such as those by Dr. Rick Grant, Dairy Scientist at UNL.
Objective 3: Create a protein degradability database on annual forages.
Final ruminal protein degradability values were not available until late summer, 2000, which was too late to include in the 2001 Nebraska Beef Report from the UNL Department of Animal Science. These results will be included in the next Nebraska Beef Report at the end of 2001 and in appropriate publications for animal science related topics. The research techniques used for this process were not as precise as expected, and are still undergoing modification by animal scientists at the University of Nebraska and other institutions. The observations to date indicate that rumen protein degradability of annual forages harvested before seed maturity ranges from about 90 to 95% of crude protein levels, which has also been reported by others in growing perennial forages. Precision of the currently used techniques did not allow differences to be discerned between cultivars or crops tested in our trials.
Objective 4: Monitor potential concerns for annual forage production, such as pest problems, soil water status and forage nitrate levels.
There were no pest problems of any consequence, and no treatments for pest control were necessary in the forage trials. There were some problems in weed control because of herbicide limitations related to other crops in small plot areas, but hand weeding solved the problem in the irrigated research plots.
As mentioned previously in the conclusions for Objective 2, soil water status was apparently a major factor in stopping growth of dryland summer annual forages, resulting in advanced maturity and drastically reduced crude protein levels from the first year when total amount and timeliness of rainfall were more favorable. Testing for forage crude protein levels cannot be overemphasized in these situations. A similar conclusion was made in regard to nitrate nitrogen levels, which can be high enough in grass type forages to use precautionary methods for safely feeding them to livestock or eliminate from the diet if necessary. However, the major cause appears to be nitrogen fertility levels in the soil from current or previous N applications. If in doubt, the prudent response would be to test the forage for nitrate so that precautionary feeding management can be initiated if necessary.
In the High Plains region, winter wheat has been a major crop for dryland farming because its growing season was a good fit with relatively more moisture in the spring than in summer and with the long established practice of wheatland being idle in a fallow year between wheat crops in order to store up enough soil moisture to produce an acceptable seed yield. Low wheat prices and ever increasing costs of production have forced producers to look at ways of growing alternative crops during the usual fallow year to try to improve whole farm income. Annual forages can be one of those crops, especially for integrated crop and livestock systems. Moisture is usually adequate in the spring to grow some forage which can then be harvested or grazed long enough before seeding the next wheat crops so that enough moisture is left to start the wheat crop. An important contribution to whole-farm sustainability in the integrated crop and livestock system can be made by annual forages when there is not enough acreage of permanent pasture available or when production of permanent pastures is severely limited by lack of rainfall or other climatic problems. That was demonstrated in the Central High Plains in the summer of 2000, when productivity of dryland pastures was severely depleted.
After seeing progress reports of university annual forage trials involving the brown midrib (BMR) sorghum and sorghum x sudangrass hybrids and interacting with researchers doing the work in this SARE funded project, several producers in the Central High Plains planted substantial acreages of BMR hybrids in the summer of 2000. Some seed companies have achieved similar improvements in feed value by selecting for this trait in non-BMR hybrids, but the availability of any cultivars with improved digestibility and energy availability is a major step forward in the development of annual forages that will benefit livestock operations. Therefore, the adoption of these new cultivars should proceed quickly, especially as further improvements are made with long standing plant breeding methods of crossing this trait into existing lines that have other favorable characteristics. While the proof of the benefits rests with animal feeding trials, there have been enough results generated to date with dairy and beef cattle in trials at several institutions to suggest that operators will see rather impressive benefits in animal performance from the feeding of these forages. Inclusion of these forages into cropping systems can have other benefits such as better weed control and reduced soil erosion, but the major contribution could be improved whole-farm economic stability.
As an important step in the completion of this project, Paul Burgener, Research Analyst in Agricultural Economics at the UNL Panhandle Research and Extension Center, was asked to do an economic analysis on the production and utilization of summer annual forages in the Central High Plains. This analysis is included as an attachment to this report, and was directed to summer annual forages because this was the group with the least available information and where the need and potential for annual forages in the Central High Plains were the greatest. The analysis compares the costs of producing, harvesting and feeding as hay, and/or grazing of three types of summer annual forages, based on forage dry matter yields averaged from the research results for dryland and irrigated forages summarized in this final report. While many producers already own haying equipment for other crops that allows them to harvest and feed annual forages as a part of an overall system for crop and livestock production, the economic analysis shows reduced costs for windrowing annual forages in late summer or fall for fall or winter grazing in the windrow. This practice has been done successfully in research projects and in production operations in recent years, even with snow cover on the ground because livestock still find the forage which appears to maintain relatively good feed value in the windrow.
Adoption or increase of annual forages in production systems in the Central High Plains has already been stated in previous sections of this report. As producers see a need to intensify, diversify, or integrate components in their production systems, they are looking at annual forages as one alternative to increase or stabilize livestock production where the productivity or consistency of forage production in permanent pastures presents rather high risks of occasionally running out of feed.
The quick adoption of the brown midrib (BMR) forage hybrids by innovative producers in this region is a witness to the potential for increased production of these forages in the area. Limited seed supplies of some BMR cultivars were sold out in the region in the summer of 2000. Seed supplies will no doubt be increased in 2001 and in subsequent years.
A testimonial letter from Alton Lerwick in Scotts Bluff County, NE, is included as an attachment and indicates a strong preference by his beef cow herd for BMR sorghum x sudangrass. Jerry McRoberts in Cheyenne County, NE, and David Kaufman in Scotts Bluff County, NE, and Goshen County, WY, enthusiastically planted BMR hybrids in 2000, and even though low rainfall limited production, they have indicated plans to plant them again, based on their potential to improve animal performance and maintain body condition.
Involvement of Other Audiences
University research and Extension workers in Nebraska, Wyoming and Colorado have been given progress reports of annual forage trials, as well as seed suppliers and seed company representatives who are on a mailing list. They are also receiving final report information. Several hundred producers and representatives of agencies such as NRCS have attended field days, tours, and meetings where reports of annual forage trials were presented. These groups also received progress reports in regional publications such as the Business Farmer weekly and in the University of Nebraska annual Beef Report which is distributed by mailing list to producers in Nebraska and nearby states and to research and Extension workers.
Educational & Outreach Activities
Dissemination efforts to date have already been stated in this report. Remaining tasks are articles in refereed journals to document and integrate the results of annual forage trials into the research information channels.
Areas needing additional study
The extent to which production of various classes of livestock can be affected by the feeding of annual forages needs to be studied further. While there are limited results of feeding trials to date, these results show good potential for improving animal performance when a crop cultivar has been selected for increased digestibility, which is usually accompanied by increased dry matter intake. This combination can have a substantial benefit in animal performance.