[Note to online version: the original report contained tables and figures that it was not possible to include here. The regional SARE office will be happy to send you a complete hard copy of the original report. Just contact Western SARE at (435) 797-2257 or firstname.lastname@example.org.]
The primary goal of our project is to develop forage production systems that extend the grazing season in the fall and provide more forage in the spring through overseeding of vegetable crops and irrigated pastures, and increased integration of crops and livestock. Overseeded species tested have included forage Brassicas, hairy vetch, winter rye, spring and winter oats, and triticale. The project includes a grazing study to determine the profitability of overseeding several of these crops into sweet corn to increase the forage value of the stover after sweet corn harvest. Sweet corn was harvested in August. Corn stover and annual forages were sampled in early November, and the fall grazing trial was conducted immediately thereafter. Paddocks were intensively grazed using stocker heifers for 4-5 weeks in the first two cycles of the trial, and about 9.5 weeks in the third cycle of the trial. In 1996 and 1997, total available forage was increased from 42 to 81 percent by overseeding oats or turnips, and overall nutritional quality was improved. Cattle average daily gain (ADG) and total gain per acre were not significantly improved by overseeding annual forages in either 1996 or 1997; however, the animals perhaps could have grazed longer in the oats and turnips treatments in 1996 and in the oats treatment in 1997 based on the amount of forage still left in the field in those treatments after cattle were removed. In 1998, however, average ADG and total gain per acre were improved substantially by overseeding forages. Preliminary economic analysis results from fall grazing indicate that, in terms of net gain per animal from grazing after subtracting overseeding costs, grazing oats and turnips were about as good as the control in year 1, but much better in year 3. In year 2, the control outperformed both the oats and turnips. Grazing turnips in year 2 would have resulted in the lowest returns and in year 3 the highest returns. Results from a second grazing study, spring grazing of rye and hairy vetch overseeded into sweet corn, indicate that stocker heifer gains were similar for both overseeded crops; ADG ranged from 1.6 to 1.9 for rye and 1.3 to 1.9 for hairy vetch. In the first and second year, hairy vetch forage was generally still available after the rye had been consumed, and so, for most of the replications, the animals were put back onto the hairy vetch after weighing for several more days of grazing. Trials were carried out at various farmer/rancher cooperator sites throughout the region and at the Alcalde Center in which pastures were overseeded with various summer and/or winter annual forages. We had limited success with summer annuals, and found that winter-annual forages, especially in the higher elevations where growing seasons are shorter, may offer a better chance to extend the grazing season of pastures through increased productivity the following spring or summer; but, there needs to be a good stand established by fall of the overseeding year.
Objective 1: To determine the ability of forage Brassicas and oats (Avena sativa L.) to provide late-season forage, and hairy vetch and winter rye (Secale cereale L.) to provide early-season forage, when overseeded into sweet corn stalks.
Objective 2: To determine the profitability of overseeding forage Brassicas, oats, hairy vetch, and winter rye into sweet corn stalks in terms of heifer average daily gain.
Objective 3: To determine the ability of forage Brassicas and spring oats overseeded into established pastures to provide increased late-season forage.
Objective 4: To disseminate to farmers and ranchers the results of the project.
Analysis of data is not complete at the time of this writing. The project coordinator can be contacted for updated analyses, publications, etc.
Objective 1. Crop residues are frequently grazed to add economic value to them. However, they are generally of low forage quality. Sweet corn in particular is a high-value vegetable crop that leaves significant amounts of residue after the ears are harvested. Overseeding a second crop of high forage quality into the corn could potentially increase the ability of these residues to support livestock either in the fall or the following spring. In the trials below, sweet corn was overseeded with annual forages in July of 1996, 1997, and 1998. Sweet corn was harvested in August. In the analyses completed to date, overseeding did not decrease sweet corn yield in terms of unhusked fresh weight, husked yield of marketable ears, and marketable ear number. Although stocker heifer weight gain was one of the parameters measured in order to evaluate the forage yields and quality, these weight gains may be indicative of the relative value of the forage for cows in cow-calf operations.
Animal Response to Grazing–Fall Study. Corn stover and annual forages were sampled in early November and fall grazing trials were conducted immediately thereafter. Fall grazing treatments were corn stover alone, stover+oats, and stover+turnips, grazed from mid November to mid December (1996 and 1997) or mid January (1998-1999). Stocking rates were about 5 heifers/acre. In 1996 and 1997, total available forage was increased from 42 to 81 percent by overseeding oats or turnips (see Fig. 1), and overall nutritional quality of the pasture appeared to be improved. Cattle average daily gain (ADG) and total gain per acre were not significantly improved by overseeding annual forages in either 1996 or 1997 (see Figs. 2 and 3); however, the animals perhaps could have grazed longer in the oats and turnips treatments in 1996 and in the oats treatment in 1997 (see Fig. 1).
In 1998-1999, however, ADG and total gains per acre were improved by overseeding either oats or turnips compared to the non-overseeded control. (see Figs. 2 and 3). One possible reason that overseeding oats or turnips gave higher gains in this year is that the animals consumed the feed at a lower rate and thus were in the paddocks about twice as long as in either of the two previous years. This in turn may have allowed more time for the digestive systems of the animals to adjust to the overseeded forages and thus have greater response to them. Other factors may have been involved also; however, the results from this third cycle of the study indicate that overseeding has potential to substantially increase animal gains in this system. Further research on grazing management (time on forage, breed, etc.) is necessary to more fully establish the potential of this system as well as develop specific recommendations.
Animal Response to Grazing–Spring Study. Corn stover and winter-annual forages were sampled in mid April, and spring grazing trials were conducted immediately thereafter. Spring grazing treatments were stover+rye and stover+hairy vetch. Both treatments were grazed for 29, 34, and 42 days in years 1, 2, and 3, respectively. Stocking rates were about 5 heifers/acre. Although the cattle weight data have not yet been analyzed statistically, the mean gains during these grazing periods indicate that ADG and total gain per acre were similar for rye and hairy vetch treatments. Cattle gained well, especially in the second and third year. ADG ranged from 1.6 to 1.9 for rye and 1.3 to 1.9 for hairy vetch. In the first and second year, hairy vetch forage was generally still available after the rye had been consumed; so, for most of the replications, the animals were put back onto the hairy vetch after weighing for several more days of grazing.
Plant Response to Grazing Study. Another study began on land of San Juan Pueblo and continued at the Alcalde Science Center. In this study we tested the ability of combinations of winter and summer annuals, overseeded into sweet corn, to provide grazing in the fall and also the following spring. Treatments were stover+rye+turnip, stover+rye+rape, stover+hairy vetch+turnip, and stover+hairy vetch+rape. These data are being analyzed at the time of this writing.
Objective 2. These are preliminary economic results, and are based on the weights, grazing time, stocking rate, etc., used in the fall grazing study under Objective 1. Monthly prices for heifers in the appropriate weight classes from the Clovis Auction (Clovis, NM) were obtained (USDA-AMS, various years). If cattle had not been grazed on any of the treatments, they would have been sold in November at the weights recorded in the trials. For the economic analysis, these animals were assumed sold in November. The cattle in the trials grazed until December (in 1996 and 1997) or until January 1999 (for the 1998 trial), and thus were assumed sold in December in 1996 and 1997 and January of 1999 at the prices and weight classes appropriate to those months. The financial gains calculated in Table 1 represent a combination of prices and increased weights from grazing.
From the gross incomes, the costs of seed and planting the overseeded crops can be subtracted to obtain a return to land, capital, management, and risk (column 6). If turnips and oats require irrigations in addition to what the corn has received, the additional cost of irrigating would affect these results. However, late summer and early fall rains are common in northern New Mexico and irrigation requirements are unpredictable and were therefore left out of this preliminary analysis.
These results were obtained assuming that cattle are stocked 5.26 head/acre, equivalent to the 2 animals per .38-acre paddock in the trials. The cost of oat seed was $0.18/lb, the actual cost of the seed used in the study. Commercial turnip seed costs were used ($5/lb) (some turnip varieties can cost more and some can cost less than this depending on year and supply). Seeding rates assumed were those used in the trials: 100 lb/acre for oats and 5.2 lb/acre for turnips. Planting costs were estimated using an accomplishment rate of .10 for a 35-hp tractor pulling a broadcast spreader. An accomplishment rate of .10 means that the tractor could seed an acre in six minutes or 1/10 of an hour.
These preliminary results indicate that grazing oats and turnips were about as good as the control in year 1, but much better in year 3. In year 2, the control outperformed both the oats and turnips. Grazing turnips in year 2 would have resulted in the lowest returns and in year 3 the highest returns. These preliminary results point to the apparent desirability of waiting to market cattle later in the fall to achieve higher prices. However, prices do not uniformly improve later in the fall. They dropped from November to December in 1997 in all but the 500-600 pound weight class (Table 2). In year 3 of the trial, waiting until January to sell turned out to be good because of the additional weight gains rather than the improved market prices. In years 1 and 2 (1996 and 1997), however, prices improved considerably in January of the following year, and oats and turnips might have been clear winners had the animals been grazed until January in the first two years of the trial. Overseeding low-cost fall grazing crops can help small cattle growers if they manage their herds so that they can time the market.
Another way to examine the results is to look at the cost per pound of gain. In year 1, the marginal costs per pound of gain (as compared to the control) from grazing oats and turnips were $0.13 and $0.17, respectively. In year 2, the marginal costs per pound of gain were $0.11 and $0.17 for oats and turnips, respectively. However, in year 3 the marginal cost per pound of gain was only $0.06 for both oats and turnips, because more pounds were added by the additional days on feed, but no marginal net costs were added.
One could argue that additional management and capital costs were actually incurred, but for this preliminary analysis they were excluded. More complete economic analyses are underway, including analyzing returns to land and risk (which would include rather than exclude management and capital). This more complete analysis will also examine whether cattle should be sold without even planting the sweet corn, taking into consideration cattle prices, market prices for sweet corn, weight gains from grazing, and the variability in these prices and yields.
Objective 3. Not unexpectedly, and consistent with information in the literature, overseeding annual forages into irrigated pastures without herbicides and/or expensive no-till seeding equipment was the most difficult part of the project. However, for most of the producers in the region who have irrigated pastures or meadows, this is one of the few practices they would be able and/or willing to undertake to extend the grazing season on these fields.
Overseeding pastures with brassicas and spring oats had varied results. Stands were often poor. In plots or parts of plots where turnip stands were fair, yields in the fall were low. Oats yields were generally better when stands were adequate. However, the few cases where results were fair indicate more research could be done to further investigate the overseeding of summer annual forages for increased fall pasture yields.
Given the limited success with summer annuals, we tested some winter annuals (winter wheat, rye, triticale, winter oats, hairy vetch) for their capacity to provide increased forage the following spring. To date, we are finding through these trials that winter-annual forages, especially in the higher elevations where growing seasons are shorter, may offer a better chance to extend the grazing season of pastures through increased productivity the following spring or summer; but, there needs to be a good stand established by fall of the overseeding year.
A total of 10 on-farm trials were initiated. Drought and water availability in some years decreased the total number of on-farm trials that were carried out. Of those carried out, animal depredation, drought, and other factors decreased the number of trials from which samples were actually collected. These factors, however, are not uncommon for the farmer/rancher and reflect the challenge that exists for extending and/or increasing cool-season pasture productivity among the limited-resource farmers and ranchers of the region. Below are site-years where somewhat positive results were obtained:
Canjilon, NM. In this study, various annual forages were overseeded into the pasture/hayfield. Forages were overseeded in July into the pasture after a light disking. Predominant grasses in the pasture were orchardgrass and smooth bromegrass. The pasture also contained timothy, kentucky bluegrass, and alfalfa. The yields in Figures 4 and 5 were taken in June of the year following overseeding.
Establishment of hairy vetch was good in the 1997 study and fair in 1998. Establishment of the cereals was fair to poor in both years. Although the results have not yet been analyzed statistically, it appears that overseeding hairy vetch may have the potential to affect overall yield as well as affect the yield of the original pasture species.
Zuni, NM. Winter rye, winter oats, winter wheat, and triticale were overseeded into a mixed-species pasture in September 1997. Data were collected in spring 1998. Although not yet analyzed statistically, mean yields are given in Table 3.
It appears that in general, except for oats, the cereals had the tendency to increase overall pasture yield. It is important to note also that the cereals tended to decrease the yield of the original pasture.
Objective 4. Activities/products regarding dissemination of findings to date are:
• The project and early results were discussed at a Forage Seminar sponsored by the Zuni Reservation Cooperative Extension Service; February 26, 1997; 22 people attended.
• A tour of the project’s research trials at the Alcalde Center was given to a group of about 8 producers (the Tucumcari Farm Improvement Club); May 9, 1997.
• A tour of the project’s research trials at the Alcalde Center was given to the general public as part of a major Field Day held at the Alcalde Center; August 17, 1997; 280+ people attended the Field Day.
• A slide presentation and tour of the project’s research trials at the Alcalde Center was given to the Administrative Council of the Western SARE program; August 28, 1997.
• A presentation of the project was given to a local Kiwana’s Club; September 23, 1997; 11 people attended.
• A slide presentation of early results from the grazing study (Objective 1) was presented to 40-50 faculty and students of New Mexico State University in Las Cruces, NM; October 17, 1997.
• A research paper (in poster form) covering first-year results from the grazing study (Objective 1) was presented to researchers, extension personnel, agricultural consultants, and students at the American Society of Agronomy’s annual meetings in Anaheim, CA; one additional oral presentation at these meetings also briefly discussed project activities; abstracts from these presentations have been published; October 27-30, 1997.
• The project was discussed with a group of 8 students and their instructor from Prescott College; July 1, 1998.
• A tour of the grazing trial was given to a group of about 16 students and their instructor from New Mexico State University; October 8, 1998.
• The overall project was discussed, and a tour given of the Alcalde Science Center trials, to the general public as part of a Forage and Livestock Field Day held at the Alcalde Center; September 27, 1998; about 110 people attended.
• An on-farm field day was held at Canjilon, NM, on June 26, 1999. Results of the Leo Rivera on-farm site were discussed.
• Results to date of the project were featured at a field day entitled “Relay-Intercropping Research Review.” The field day took place at the Alcalde Science Center. A slide and overhead presentation of the results was presented as well as a field tour of demonstration plots. A booklet was prepared and distributed that included results of the grazing study and the overseeding study at Canjilon, NM.
• Steve Guldan presented a seminar to New Mexico State University’s Department of Agronomy and Horticulture covering the results to date of the project. The seminar took place on September 24, 1999, at Las Cruces, NM.
Although we do not have all of the field data analyzed to make conclusive statements regarding positive benefits or impacts, results to date from the grazing study indicate that significantly more forage is available for livestock grazing corn stover overseeded with turnips or oats compared with grazing the stover alone. It appears that, depending on type of cattle and cattle management, either overseeded crop has the potential to increase weight gains in the fall-winter. This would increase efficiency of land use by integrating sweet corn and livestock production. The on-farm studies at Canjilon and Zuni, NM, indicate that there is potential to increase pasture yield by overseeding winter annual forages; however, stand establishment is critical and more research is needed to look at other species as well as other possible seeding or establishment methods. Continued research based on what is being learned at Canjilon and Zuni could lead to increased forage production on thousands of acres of cool season pasture in the Southern Rockies.
Educational & Outreach Activities
Accomplishments for dissemination of findings are listed above under “Specific Results, Objective 4.” Project publications, news releases, and presentation of results at conferences, producer meetings, field days, etc., will continue into the future.
Because of our results to date, we believe it is premature to develop specific and/or final recommendations. However, preliminary results show increased crop production and increased cattle weights through overseeding annual forages; however, due to variable results from year to year, more research on some aspects of the project may be required to refine recommendations. Interested producers are encouraged to try overseeding oats, or low-cost turnip seed, into sweet corn on a small scale. If the producer feels yields are high and overseeding costs are low enough, a paddock could be seeded that is large enough to observe the grazing of 2 or more animals. The key is that the producer slowly integrate the practice into his/her system while paying close attention to costs vs. benefits.
Overseeding of cool-season pastures with annual forages is not generally recommended at this time.
Benefits of any of the above practices will vary depending on environmental and management factors.
Reactions from Farmers and Ranchers
Producers have expressed interest in the project through questions, comments, and general discussion during field tours and field days.
To date, 6 producers have been involved in the project, primarily as farmer/rancher cooperators for the on-farm/ranch trials. They primarily assisted us in allowing us to use their land and in choosing the species to be used on their site.
Number of farmers or ranchers in attendance at:
Field Days–about 350-450
Other events (specify): seminar–22
Areas needing additional study
On-farm results to date indicate that future research could focus more specifically on testing additional biennial or winter-annual forages for overseeding, particularly at the higher elevation sites. Preliminary results from the Zuni Pueblo site indicate that triticale may have more forage growth and/or quality in the spring and thus would also be a good candidate to test as an overseeded crop in sweet corn. Results from the Canjilon site indicate that hairy vetch–when established well–can be very productive in an established cool-season pasture. Thus, additional research is needed on simple, inexpensive pasture-overseeding establishment methods.
The grazing study indicates that response to corn-stover+overseeded crop can vary depending upon season and the group of cattle. Future research could address how and why cattle responses may vary. In addition, stands of overseeded crops, except perhaps rye, indicate that seeding rates could possibly be reduced without decreasing stands; this would decrease the costs of overseeding.