Annual Legume-Based Systems for Sustainable Integrated Crop/Livestock Enterprise Diversification on the Central High Plains

Annual Legume-Based Systems for Sustainable Integrated Crop/Livestock Enterprise Diversification on the Central High Plains

Summary

Heifer gains on AWP were equal to perennial range pasture. All Medicago rigidula establishment (broadcast or drill into clean till or stubble) methods were equal. Examination of M. rigidula within alternative dryland wheat rotations revealed that a wheat-medic, medic/cattle grazing and hay production rotation was the most profitable. Selection for superior winter hardy pea lines continued. Pea can replace a portion of corn-soybean meal at ~16% of hog and heifer & ~30% of lamb total diet. Nutritive value of ‘Dun’ and ‘White (Yellow)’ pea was similar. Grazing chickpea with sheep for weed control under dryland and irrigated produced mixed results.

Objectives/Performance Targets

(1) Expansion of the Austrian winter pea grazing/wheat system to encompass beef production.
(2) Determine optimum medic ‘ley’ establishment practices.
(3) Identification of pea lines for optimum winter survival, and forage and/or grain quality and yield.
(4) Nutritional and economic value determination of ‘dun’ and ‘white(yellow)’ grain pea types.
(5) Development of protocol for biological control of weeds in chickpea for organic production.

Accomplishments/Milestones

Objective (1). Expansion of the Austrian winter pea (AWP) grazing/wheat system to encompass beef production. As reported in the first annual report, AWP was seeded in September 2003 at UW-SAREC in an attempt to repeat the study. Thanks to good autumn moisture pea establishment was very good at this location. In the spring the six acres of AWP was fenced into three pastures of equal size. An adjacent, range pasture area was also fenced into three pastures with the same equivalent dry matter forages as the pea pastures. Each of the six pastures were stocked for six weeks starting 10 June with three bred heifers/pasture. The AWP heifers gained 0.825 lb/d vs. 1.08 lb/d for the heifers on range, with a standard error of 0.166, average daily gain did not differ (P = 0.389) between treatments. Thus, grazed AWP was equal to perennial range pasture with no ill effects. The stocking rate could have been higher because of timely rains during the stocking period produced higher than anticipated forage production. This resulted in a longer than anticipated grazing period. AWP was seeded in September 2004 with the objective off repeating the study at a higher stocking level.

Larry Held coordinated the evaluation of the economic effectiveness of incorporating alternative legume crop and cattle grazing rotation with a traditional WW-SF system. Because of the failure, caused by drought in 2003, a decision was made to shift the graduate student project away from AWP to annual Medicago. A Master of Science thesis was completed in 2005 that examined the profitability of including Medicago rigidula within the dryland winter wheat-fallow rotation. This thesis examined four alternative rotations for profitability. The first rotation(#1) was a traditional wheat – fallow system (W-F), utilizing both chemical weed control and conventional tillage weed control. (#1= WF). The second rotation (#2) was a legume rotation with a wheat-medic medic cattle grazing system (#2 =W-M-M Graze). The third rotation (#3) was a wheat-medic, medic/ cattle grazing and hay production rotation (#3 =W-M-M Graze/Hay), utilizing two years of grazing and two years of hay production. The fourth rotation (#4) was a continuously alternating wheat and medic cattle grazing rotation (#4 =W-M-W-M Graze).
Rotation #3 (W-M-M Graze/Hay), including both grazing and hay production, was by far the most profitable (net return = $43.26/ acre). Rotation (#4) with grazing and no hay was less profitable ($8.64/acre), followed by Rotation #2 with two grazing years and no hay was the least profitable ($4.07/acre) of all medic rotations. However, Rotation (#1), winter wheat-fallow with no medic hay or grazing, was by far the poorest of all rotations, rendering a net loss of (-$8.41/acre).

Objective (2). Determine optimum medic ‘ley’ establishment practices. As mentioned in the first annual report a trial was established on dryland and, because of the drought in 2003, on an irrigated site at SAREC near Lingle WY in September of 2004. There was good emergence and establishment of medic at both sites. The project was assigned to a graduate student. Results indicated that all establishment methods (broadcast or drill into clean till or stubble) were equally successful in the establishment of Medicago rigidula. Dry matter yields at the dryland and irrigated sites averaged 7,250 and 11,050 lb/acre by the end of June. The experiment will be repeated in 2005-06 as trials were established at both sites in the autumn.

Objective (3). Identification of pea lines for optimum winter survival, and forage and/or grain quality and yield. As reported in the first annual report, one selection that demonstrated superior early spring forage production with upright stature was being fast tracked into seed increase for possible release as a forage pea forage hay production. This seed increase unfortunately was lost to wind damage during the spring of 2004 and no seed was recovered.
Robin Groose the individual in charge F1 hybrids cross-combinations among diverse pea lines, including AWP cultivars, AWP Plant Introductions, as well as selected spring pea lines has no additional information to report at this time.

Objective (4). Nutritional and economic value determination of ‘dun’ and ‘white (yellow)’ grain pea types. Bret Hess coordinated this effort in year 2. A graduate student was assigned to the project. Feeding trials were completed. Field pea grain can be fed to finishing hogs at 16% of the total diet. Hogs fed Dun field pea had similar growth performance and carcass characteristics as hogs fed White (Yellow) pea. Greater daily BW gain by heifers fed supplements with peas during the first 30 days resulted in greater daily BW gain by these heifers overall. Faster rates of gain by heifers fed pea do not appear to be related to greater feed consumption because gain efficiency was greater for these heifers. Thus, based on growth performance, field pea can replace traditional corn-soybean meal supplements fed to developing replacement heifers. Daily gain was less for lambs fed Dun pea during the last 56 days of the experiment, but greater growth performance by these lambs during the first 63 days of the experiment resulted in greater overall growth performance. Carnival ‘white (yellow)’ field pea can comprise approximately 30% of the ration without effect on growth performance, whereas Forager ‘dun’ pea may have greater replacement value in lamb feedlot diets.

Overall, field grain pea can replace a portion of corn-soybean meal of many rations. The replacement level came to about ~16% of the total ration for hogs and heifers & ~30% of the total diet for feedlot lambs. In the case of the heifers, this was a total replacement. It was not a total replacement for the other species because their diets typically contain greater amounts of corn and soybean meal. At the level of replacement indicated, the nutritive value of the two field pea varieties seem to be similar. In light of discounted market prices, Dun pea may serve as an economically viable alternative protein supplement.

Objective (5). Development of protocol for biological control of weeds in chickpea for organic production. Stephen Miller coordinated the effort to determine optimal bio-control practices for weeds in a chickpea field. A graduate student was assigned to the project. As mentioned in the year one report, this research was conducted at two sites in year 2 with modifications in herbicide and sheep grazing treatments. Results from a dryland site in year 1 looked quite promising, as the sheep indeed seemed to prefer the weeds to the chickpeas. However, drought conditions and a hail storm prevented any yield data from being collected at the site. In year 2, the grazing study was repeated on dryland and irrigated ground with mixed results. Under dryland conditions, the sheep once again spent most of their time grazing on the weeds. The irrigated plot resulted in much different results. The predominant weed species in the irrigated trial was common lambsquarters, which has a relatively high feed value but is rather unpalatable to sheep. Rather than eating the weeds, the sheep seemed quite content to travel down the rows of chickpeas, leaving the lambsquarters untouched. Any chickpeas that were left behind were soon choked out by the overwhelming weed pressure.
In addition to grazing studies, over forty different herbicide treatments were evaluated for weed control in year 1, and narrowed down to only those that showed promise for further evaluation. Several treatments provided consistent weed control across all years of research. In particular, mixtures of either Prowl, Outlook, or Dual Magnum with Spartan herbicide applied preemergence seemed to provide season long weed control. No promising postermergence herbicide options were identified.

Impacts and Contributions/Outcomes

The medic establishment experiments, Objective (2), was a featured stop at the annual SAREC (Lingle, WY) summer field day. Approximately forty people listened to Jim Krall discuss the experiments. Robin Groose spoke at the pea selection nursery about progress being made in the development of winter annual peas, Objective (3), at the same field day. Additionally, progress has been made toward the release of a variety of Medicago rigidula. A variety release application has been approved by the UW variety release committee and the variety will be marketed under the trade market name of ‘Laramie.’ Jim Krall accepted an invitation to speak on ‘Ley’ farming at the WSCS meetings in Bozeman, Mt. A manuscript on the performance of Medicago rigidula has been reviewed for publication in the Agronomy Journal. It is expected that it will be accepted for publication after revisions have been completed. A Master of Science thesis, under the direction of Larry Held, was completed in 2005 to examine the profitability of including Medicago rigidula with alternative dryland winter wheat rotations. The thesis citation is: Lewton, Brian, “An economic evaluation of Medicago rigidula in alternative crop rotations winter wheat in Southeastern Wyoming”, M.S. thesis in Agricultural Economics. University of Wyoming. August, 2005. A paper was prepared, under the direction of Bret Hess, and was presented at the WASAS meetings and published in the proceedings on the results from the hog feeding trial. Steve Miller, directed the development of an article on the chickpea research, Objective (5), that was recently submitted for publication in the UW-AES annual capstone magazine titled ‘Reflections.’ He also directed the graduate student thesis that was recently completed on this topic of research. A multi-state pea production guide is scheduled to be available to the public during early 2006. The publication is a joint effort between university specialists from Wyoming, Nebraska and South Dakota. “Pea Production in the High Plains” is a comprehensive publication providing timely advice on the production and utilization of pea grain as well as pea forage. Jim Krall and Steve Miller were members of the writing team.

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