Annual Legumes in Fallow as an Integrated Crop/Livestock Alternative in the Central Great Plains.

Annual Legumes in Fallow as an Integrated Crop/Livestock Alternative in the Central Great Plains.

Summary

In Wyoming, black medic (M. lupulina ) and M. rigidula. plots established in previous years were monitored for regeneration form the seed soil bank. Winter survival of M. rigidula was also monitored. While regeneration was very good as previously reported for M. rigidula winter survival was poor. Importantly late summer establishment (8/17/01) from this seed back was 5.5 plants/square foot which is considered good. This is an important finding because it indicates that the seed softening pattern is matching the environment producing seedlings early enough for establishment of a winter hardy medic from the two year old seed bank. The naturalized black medic showed the highest potential for spring regeneration. On May 4 the pasture block contained an estimated 90 plants/square foot. In 2001, a long term Austrian winter pea (AWP) pasture block was replaced with M. rigidula. Fall seedling counts averaged 2.2 plants /square foot. The year 2001 was the last year of evaluation of winter wheat plant back in the AWP study. An analysis of long term results was made. Long term, grazed pea significantly reduce soil water compared to fallow. However, this had no significant negative effect on the subsequent wheat yield. In effect, although there was a trend toward lower yield after peas of 2.9 bu/acre, wheat protein was significantly higher by %1.7. In Austrian winter pea breeding, efforts focused on evaluating F2 generation plants, making selections on the basis of survival, productivity, and diversity of type, and establishing F3 family rows of selections in October 2000. We made approximately 450 selections among the 3200 surviving plants. These were single-plant threshed to establish 20-foot F3 family rows that were seeded on 21 September 2001. Tremendous variability for time of flowering and maturity was observed. We anticipate isolation of early maturity grazing and feed pea types that should finish by July allowing for a 10-week true fallow before wheat planting, as peas are grown as a partial replacement for fallow in the winter wheat-summer fallow system. Conversely, we also expect to isolate late-maturity types that might be grown for full-season grazing and/or high-yield feed pea production to be followed by a summer crop and then a fallow before a subsequent wheat crop. Additional genetic variation was incorporated into the pea breeding program as a small (1000 plants) nursery was established in September involving F2 seed and self-progeny of three-way crosses from additional hybridizations made in summer 2000. A thesis in economics was completed by Andy Haag. This profitability analysis of alternative dryland crop rotations for southeast Wyoming, including: Wheat-Fallow, Wheat-Corn-Fallow, Wheat-Sunflower-Fallow, Wheat-Corn-Millet-Fallow, and Wheat-Sunflower-Millet-Fallow. Each of these five rotations were adjusted from traditional fallow, to include either: grazing AWP with lambs as part of the fallow rotation, or plowing down AWP as green manure, resulting in a total of 15 rotations. Cost and return enterprise budgets were developed for each of the crops using current prices and custom costs for field operations, along with average historic yields and prices for crops and lambs. The pea-graze rotations proved to be economical, in generating higher rates of return than their counterparts without AWP. When compared to the counterparts of either no AWP or grazing AWP, the five rotations with plow-down of AWP for green manure were by far the worst in terms of profitability, due in part to greater wheat yield reductions, and no offsetting measurable short-term gains. Potential long-term benefits of improved soil quality and possible higher wheat yields in the long-term could not be measured in this analysis. Incorporation of AWP in the fallow period would be better implemented within the context of extended rotations, versus a shorter 2-year wheat fallow option, for a number of reasons: extended rotations have the potential for higher profitability, the adverse affect of wheat yield penalties occurring after AWP, are reduced from one-half to either one-third or one-fourth of total farm acreage, the potential for blight in AWP is lessened with longer rotations, and compared to a traditional 2-year rotation, extended 3 or 4-year rotations would require management of fewer lambs for a given farm acreage. This may be an issue if uncertainty exists with respect to finding either adequate year-to-year lamb supplies or producers interested in leasing AWP as a source of grazing forage. In eastern Colorado wheat-corn-fallow rotations have been shown to be environmentally and economically sustainable. We have been studying the feasibility of planting (AWP) after corn harvest into the time slot that would have been fallow. The AWP is harvested the next summer and can be used as a cover crop or for livestock forage. AWP is allowed to grow until June, and at that point we remove differing amounts of the peas as forage. We measure total biomass of peas, N content of the pea forage, and calculate N return to the system. We also track soil water usage by the peas and the amount of water accumulated in the soil between AWP harvest and wheat planting. Fall planted AWP forage yields have averaged over 2100 lbs/A over both sites from 1995 to 2000. Weeds, in particular Kochia and Russian thistle, are a problem in some years when pea growth is slow. However, these weeds are quite immature at pea forage harvest and therefore do not diminish the quality of the forage. Wheat yields following peas have been about 5.5% less than wheat grown after fallow. Economically speaking the value of the pea forage has been greater than the value of the wheat yield loss. A thesis (David Poss) was completed in 2001. AWP left for green manure increased soil C in the surface one inch of soil relative to fallow treatments a the two no-till sites, Sterling and Stratton, CO, but had no effect on soil C at the WY experiment which involves tillage. Field days were conducted at both Colorado sites in June and July of 2001and at Archer, WY in July.

Objectives/Performance Targets

1. Determine the feasibility of utilizing ley cropping systems to integrate livestock into the winter wheat-summer fallow rotation (WY).

2. Determine the efficiencies of water-use, biomass and N-fixation when incorporating peas and medic into the wheat-corn-summer fallow cropping system (CO).

3. To evaluate the economic effectiveness of incorporating alternative legume crop and livestock grazing rotations with a traditional winter wheat-fallow system (WY).

4. Demonstrate the effectiveness of incorporating legumes into the agroecosystem through on-farm research and demonstrations, field tours and media dissemination (WY, CO).

Accomplishments/Milestones

Objective 1. (WY) Medic – UW Research and Extension Center at Archer, WY.

Black medic (M. lupulina ) and M. rigidula. plots established in 1998 and 1999 were monitored for regeneration form the seed soil bank. Winter survival of M. rigidula was also monitored 2001. While regeneration was very good as previously reported for M. rigidula winter survival was poor. The survival was approximately 6%. This was much lower than the previous years and is attributed to excessively open, dry, and cold winter conditions. Importantly late summer establishment (8/17/01) from this seed back was 5.5 plants/square foot which is considered good. This is an important finding because it indicates that the seed softening pattern is matching the environment producing seedlings early enough for establishment of a winter hardy medic from the two year old seed bank. The naturalized black medic, which was planted for the first time in 1998, showed the highest potential for spring regeneration. On May 4 the pasture block contained an estimated 90 plants/square foot.

In 2001 a long term AWP pasture block was replaced with M. rigidula on Aug. 16 using a Tye drill at the seeding rate of 3.2 lb/acre. Fall seedling counts averaged 2.2 plants/square foot. Winter survival will be assessed next spring and the pasture block grazed following the procedure used for AWP. AWP has been replaced as the pasture legume this long term study because of it’s susceptibility to Ascochyta/mycosphaerella blight and because M. rigidula has shown potential establish from the existing seed bank.

It has been observed that M. lupulina regenerates abundantly in the spring with little autumn emergence, while M. rigidula regenerates primarily in the autumn. It may that the combination of the two medics may produce the most dependable pasture. M. lupulina may fill in for M. rigidula in years where harsh winter conditions damage M. rigidula stands. This is a topic for future research.

Austrian Winter Pea – UW Research and Extension Center at Archer, WY.

The year 2001 was the last year of evaluation of winter wheat plant back. A comparison between the fallow, grazed pea, and winter wheat was made. A data table can be supplied upon request. It is important to note that wheat yields after peas and after fallow are not significantly different and that wheat protein content is significantly different. Long term, grazed pea significantly reduce soil water compared to fallow. This had no significant negative effect on the subsequent wheat yield. In effect, although there was a trend toward lower yield after peas of 2.9 bu/acre, wheat protein was significantly higher by %1.7. We wonder that even though the peas are depleting soil moisture in the rooting zone that the increase in organic matter my be improving soil till resulting in greater water retention in the root zone during the wheat production cycle and/or improved organic soil N is helping the wheat better utilize soil moisture.

In Austrian winter pea breeding, efforts focused on evaluating F2 generation plants, making selections on the basis of survival, productivity, and diversity of type, and establishing F3 family rows of selections in September. As reported previously, in an effort to breed for better winter pea survival and productivity on the Central Great Plains, 80 hybridizations among diverse pea lines were produced in the greenhouse in the summer of 1999. F2 seed was successfully produced from all of these crosses in the greenhouse in spring 2000 for field planting in August 2000. More than 80000 F2 seed were produced with an average of 225 seed per F2 family. Because of the severe drought in southeastern Wyoming, including at our Archer site, we did not plant F2 seed in late August (normal planting time) because there was essentially no soil moisture. However, Archer received a record 2.75 inches of precipitation in September so we seeded a spaced-plant nursery in early October 2000 as each of ca.18000 F2 seed plus 2000 seed of parental lines and checks were hand planted into 30 inch rows with 1 foot between plants. We anticipated that the late planting would provide an especially severe test of winter survival.

Establishment and winter survival was 30% in one half of the nursery (seed not scarified) and 5% in the other half of the nursery (seed scarified to speed germination and establishment). (We probably won’t scarify again!) We made approximately 450 selections among the 3200 surviving plants. These were single-plant threshed to establish 20-foot F3 family rows that were seeded on 21 September.

The F2 nursery exhibited tremendous diversity both within and among F2 families. Families derived from crosses involving isolines for morphological types (afilia-type, reduced stipules, acacia-type, and various combinations) segregated for these traits. Preliminary data analysis indicates disturbed segregations in some cases. Some of these materials are also segregating for yellow vs green cotyledons and smooth vs wrinkled seed (different edible pea types). Hybridizations involved both winter pea (Pisum sativum ssp arvense) and garden pea (P.s. ssp sativum) types, so we are observing segregation for these types as well. Thus, these materials could produce various winter-hardy edible types.

Tremendous variability for time of flowering and maturity was observed. We anticipate isolation of early maturity grazing and feed pea types that should finish by July allowing for a 10-week true fallow before wheat planting, as peas are grown as a partial replacement for fallow in the winter wheat-summer fallow system. Conversely, we also expect to isolate late-maturity types that might be grown for full-season grazing and/or high-yield feed pea production to be followed by a summer crop and then a fallow before a subsequent wheat crop. Additional genetic variation was incorporated into the pea breeding program as a small (1000 plants) nursery was established in September involving F2 seed and self-progeny of three-way crosses from additional hybridizations made in summer 2000.

Objective 2. (CO)

Pertaining to Colorado, legume production experience from 1995-1999 was included in the 2000 annual report. Over the entire course of the experiment we averaged 2220 and 2090 lbs/A of dry matter forage at the two sites, Sterling and Stratton, respectively. This includes years when crops failed due to winter kill (desiccation) and low rainfall. Yields of this high quality forage are profitable if you have your own livestock to utilize the forage.

Wheat production following production of AWP was closely related to the quantity of soil water stored between AWP harvest and wheat planting. Wheat yields the year following AWP production were not affected by amount of forage left on the soil surface, but were substantially affected by the presence or absence of peas in the system as was stated in the 2000 annual report. We were unable to show any carry-over N benefits from the peas in subsequent wheat or corn crops. Perhaps more cycles of the rotation are needed to allow time for the organic N in the residues to mineralize, since these were all no-till environments

Soil quality measurements continued at the two Colorado sites, Sterling and Stratton and at the Archer Wyoming site in 2001. Treatments have been in place for 5 years at all sites. The Colorado sites are managed with no-till and the Wyoming site is tilled. Soil bulk density, organic carbon, organic nitrogen, plant available phosphorus, pH, water sorptivity, and soil microbial biomass have been measured. Graduate student, Bebe Sorge, is in the process of analyzing the data and writing her thesis.

Objective 3. (WY, CO) Returns from Austrian Winter pea Grazing.

Dryland wheat producers in Southeast Wyoming, using traditional fallow cropping systems, are struggling to sustain long-term average profitability. In order to maintain or improve profitability, extended rotations, beyond two years of wheat-fallow are being considered in southeast Wyoming. These may include different combinations of winter wheat, corn, sunflowers, and millet with traditional fallow. The fallow period for extended rotations can be further modified to include annual legumes such as Austrian Winter Peas (AWP).

Haag (UW Thesis, 2001) conducted a profitability analysis of alternative dryland crop rotations for southeast Wyoming, including: 1. Wheat-Fallow (W-F), 2. Wheat-Corn-Fallow(W-C-F), 3. Wheat-Sunflower-Fallow (W-S-F), 4. Wheat-Corn-Millet-Fallow (W-C-M-F) and 5. Wheat-Sunflower-Millet-Fallow (W-S-M-F). Each of these five rotations were adjusted from traditional fallow (F), to include either: (a) grazing AWP with lambs as part of the fallow rotation (FG), or (b) plowing down AWP as green manure(FP), resulting in a total of 15 rotations, which are summarized in a table that can be supplied upon request.

Cost and return enterprise budgets were developed for each of the crops using current prices and custom costs for field operations, along with average historic yields and prices for crops and lambs. Returns from grazing lambs were based on a landowner receiving $66/head, or a 60% share of the total value of lamb (60% of $110/acre). Total value of lamb gain ($110/acre) was estimated as: (20 grazing days) x (14 lambs/acre x 0.5 lb. average daily gain) x ($0.78/lb average price for lambs). With this cost-share arrangement, a landowner is responsible for costs of providing water and fencing. Detailed cost and return estimates were summarized in Haag (UW Thesis, 2001).

Wheat yield reductions were observed with AWP in the fallow rotation. For the economic analysis, the average wheat yield for rotations without AWP was set at 31 bu/ac. Fallow rotations with lambs grazing AWP, 1a- 5a were 10% lower (28 bu/ac), and with green manure AWP rotations, 1b- 5b, 15% lower (26 bu/ac). However, lower yields with AWP rotations, were partially offset by higher wheat prices, as a result of elevated protein from wheat following AWP.

Economic performance for each of the alternative rotations is summarized in a table that can be supplied upon request, in terms of gross returns per acre of farmland, total production costs (excluding a land charge), per acre net return to farmland and the percentage rate of return to land (valued at $250/acre).

The traditional wheat fallow rotation (#1 W-F) is least profitable (1.11% rate of return to farmland) compared to other extended rotations without AWP (#1-#5). In general, extended rotations with corn did better than those with sunflowers, and 4-year rotations (#4 and #5) were more profitable than 3-year rotations (#2 and #3).

The pea-graze rotations (#1a – #5a) proved to be economical, in generating higher rates of return than their counterparts without AWP (#1-#5). For example, W-C-M-(PGF), #5a, yielding the highest overall rate of return (7.91%), was nearly 2% better than W-C-M-F, #5 (5.22%). Because of added costs required of growing AWP, the pea-graze systems(#1a – #5a) were more costly than rotations without AWP(#1-#5), however, profitability was higher as a result of extra revenue from lamb sales.

When compared to the counterparts of either no AWP (#1 -#5) or grazing AWP (#1a – #5a), the five rotations with plow-down of AWP for green manure (#1b – #5b) were by far the worst in terms of profitability, due in part to greater wheat yield reductions, and no offsetting measurable short-term gains. Potential long-term benefits of improved soil quality and possible higher wheat yields in the long-term could not be measured in this analysis. Yet, even in the absence of possible long-term benefits, The table, that can be provided upon request, shows that compared to the traditional W-F rotation (#1 = 1.11%), choosing to plow-down AWP for green manure could be slightly more profitable if done with an extended 4-year rotation, e.g., (#4b = 2.80% or #5b = 1.83%).

Incorporation of AWP in the fallow period (as an alternative to traditional fallow) would be better implemented within the context of extended (3 or 4-year) rotations, versus a shorter 2-year wheat fallow option, for a number of reasons: (1) first, extended rotations have the potential for higher profitability, (2) second, the adverse affect of wheat yield penalties occurring after AWP, are reduced from one-half to either one-third or one-fourth of total farm acreage, (3) third, the potential for blight in AWP is lessened with longer rotations, and (4) fourth, compared to a traditional 2-year rotation, extended 3 or 4-year rotations would require management of fewer lambs for a given farm acreage. This may be an issue if uncertainty exists with respect to finding either adequate year-to-year lamb supplies or producers interested in leasing AWP as a source of grazing forage.

Objective 4. (WY, CO) Wyoming medic on farm research/demonstration trials.

Two Wyoming producers, who learned about ‘ley’ farming first hand while participating in a University of Wyoming sponsored Australian agriculture study tour in 1997, participated in research/demonstration trials established in 1998. Herald, Mogul, Sava, and George medic cultivars were spring sown in large replicated strip plots leaving fallow strips (check) for comparison. As reported last year regeneration from the soil seed bank was below acceptable levels. Follow-up visits to these locations in 2001 revealed nothing new. It is speculated that the Australian medics that normally under go seed hardening during the hot Australian summer do not have the opportunity to harden properly in the Wyoming environment. These medics lack the desired winter hardiness for Wyoming so they must be grown as summer annuals therefore the hot seed conditioning period is greatly reduced leaving the seed soft at the outset of autumn/winter period where this soft seed imbibes moisture and succumbs to the adverse conditions during this period. It is also speculated that the very small seeded naturalized George black medic fell pray to tillage practices which may have buried the see to deep to allow for abundant emergence. Results as stated early in this report suggest that good black medic seed regeneration is possible when tillage is minimal.

Impacts and Contributions/Outcomes

Dissemination of Findings:

Presentations were made at three field days, plus three experiments are being conducted on farmer owned land. The field days were held 7 June at Stratton, CO, 26 June at Archer, WY and 30 July at Sterling, CO. Conference presentations include: American Society of Agronomy, Charlotte: two invited presentations at the Medic symposium, and a poster presentation.

Potential Benefits and Impacts on Agriculture:

The possible benefits were described in the proposal and have not changed. In Colorado legumes in the wheat-corn-fallow rotation would provide diversity for weed control purposes, provide extra cover during fallow, and provide a high quality forage for livestock. It is too soon for farmer adoption, but there is growing curiosity. In Wyoming grazed Austrian Winter Pea in place of fallow also provides diversity for weed control purposes, provides extra cover during fallow, and provides a high quality forage for livestock. Net return from grazing continues to look very positive. A detailed economic analysis will be possible with funding of this project and will help to further clarify the value of the system. The promising winter survival and seed bank regeneration of an experimental line of M. rigidula , may lead to the release of first true ‘ley’ farming legume variety for the Central High Plains.

Farmer Adoption and Direct Impact:

It is still too early to assess the farmer adoption. However, we believe based on inquiries that dryland pea production is on the increase. Also, interest in integrated crop/livestock systems is on the rise with researchers within the region. One CO and one KS producer has requested and has been provided seed of M. rigidula ‘SA10343’. Crop/livestock systems research activities were included in rewrite for resubmission of a major IFAFS proposal involving dryland producers and scientist in KS, NE, CO, and WY. The goal of this effort is to initiate additional research sites in NE and CO. The proposal was not funded.

Reaction from Farmers and Ranchers:

Copies of a video tape describing Australian ley farming as seen as the result of a 1997 Australian dryland crop production study tour were still being requested and delivered to agriculture cliental in 2001. We plan track the success of the one CO and one KS producer that have been provided seed of M. rigidula ‘SA10343’. In Colorado, with present AWP seed costs, farmers are reluctant to try them in their systems. Our erratic results, excellent one year and little yield another, dampen their enthusiasm.

Producer Involvement:

Number of growers/producers in attendance at:

35 Conferences
145 Field Days

Experiments are being conducted on farmer owned land. J. Baker, D. Kaufman, H. Mattson, G. Lindstrom and G. Miltenberger are important cooperators on the project. They make suggestions and manage the research on their properties in accordance with their standard farming practices where practical.

Future Recommendations or New Hypotheses:

Is it possible to replace AWP with medic in grazing trials? How would a mixture of M. lupulina and M. rigidula perform as a ley pasture mix?

Collaborators: