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

Under very dry conditions sowing medic into tilled seed beds produced superior results. This result was not noted under more typical soil moisture conditions. The pea grazing study was abandoned because of drought, but later pea regenerated in abundance from the deposited seed bank. Selection for superior winter hardy pea lines continued. One line is being advanced to seed increase for possible release as a pea for hay production. ‘Dun’ and ‘white’ grain pea were produced for feeding trials commencing year 2. Grazing chickpea with sheep for weed control revealed that chickpea exhibited good tolerance to the low stocking rate.

Objectives/Performance Targets

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

Accomplishments/Milestones

Objective (1). Expand the Austrian winter pea (AWP) grazing/wheat system to encompass beef production. A cooperator-based field demonstration trial was used to compare the economic return of grazed wheat stubble to wheat stubble containing post wheat harvest planted pea. James Krall coordinated this effort, and Boyd Yeik was the farmer cooperator. Cattle normally graze two 6.25 acre fallow (wheat stubble containing weeds and volunteer wheat) strips adjacent to the home place. One strip was seeded to inoculated AWP on 15 August at the rate 60 lb/acre air seeder with hoe openers. The other strip left as fallow. On 14 April an assessment of AWP stand and winter survival and weeds was made by recording plants within fourteen 2.7 sq ft quadrants randomly located along the length of the field strip. It was determined that AWP stand density was at an acceptable 9 live plants/sq ft. It was also noted that winter mortality was < 4%. Winter annual grassy weed levels however were high. Populations were 6 and 26 plants /sq ft for volunteer winter wheat and downy brome, respectively. To control these weeds a mixture of 8, and 32 oz of Select herbicide, and methelaided crop oil, respectively, with 1.7 lb of ammonia sulfate in 12 gallons of water per acre was immediately applied. An area of 10,000 sq ft was left unsprayed as a check. Mr. Yeik keeps weather records for the weather service. At the end of May he reported that since 15 Sept 2003 there had been only 2.25 inches of precipitation. These were drought conditions. The long-term average for this period at this location is 8.25 inches. These conditions were typical for SE WY and NE CO. The end of May was the time grazing would normally take place. Based on the number of calves available (10) and a 4-week grazing period as needed for accurate weight gain assessment it was determined that a minimum of 450 lb/acre dry matter (DM) forage would be required at this time. Clippings were made to determine level of available forage. Forage samples were collected at a clipping height of 1 inch within five 2.7 sq ft quadrants randomly located along the length of the field strip. From this sampling it was estimated that there was only 180 lb/acre DM forage with 18.4 and 84.9%, protein and in-vitro dry matter digestibility (IVDMD), respectively, and 295 relative feed value (RFV). Mr. Yiek decided to take the calves to market rather than risk it. We could not disagree with his decision. The study was abandoned after a second forage sampling took place (6/23/04). The area where winter annual grassy weeds had been controlled averaged 2,500 lb/acre DM forage 15.6 and 68.2%, protein and IVDMD, respectively, and 167 RFV. The unsprayed area averaged 1,294 lb/acre DM forage16.2 and 52.2%, protein and IVDMD, respectively, and 95 RFV. As a follow-up, Mr. Yiek reported recently that he has “a fine-looking field of AWP that has volunteered from seed.” He plans to leave it through the winter. He commented that it should have green manure value, and it has provided a break from wheat, which seems to be helping with downy brome control. Additionally, AWP has been seeded in September at UW-SAREC in an attempt to repeat the study. Thanks to good autumn moisture, pea establishment has been very good at this location as well. Larry Held will coordinate the evaluation of the economic effectiveness of incorporating alternative legume crop and cattle grazing rotation with a traditional WW-SF system when field work is completed. Objective (2). Determine optimum medic ‘ley’ establishment practices. One cooperator (Robert Wagner) and one UW Sustainable Agriculture Research and Extension Center (SAREC) based field trial were used to demonstrate the medic ‘ley’ system with emphasis on identification of low-cost methods that optimize establishment of a selected winter-hardy M. rigidula line SA10343 for long-term pasture ‘ley’ production. The trial consisted of two wheat stubble residue levels (standing stubble and clean-tilled fallow), two medic sowing methods (drill and broadcast), and two post-sowing treatments (prickle-chain harrow and no-till). Plots were replicated four times and measured 20ft by 30ft. The M. rigidula seed was inoculated with Rhizobium inoculant and sown at the rate 8 lb/acre pure live seed. Dry August conditions at the Wagner farm delayed sowing until after a 0.25 inch rain took place on 4 September. Sowing at SAREC took place on 29 August 2003. As a consequence of the drought an attempt was made to apply supplemental water through flood irrigation at the SAREC location. As with the Wagner location, autumn and spring observations were made, as well as assessment of mid May dry matter forage production. Although, there were significant treatment difference (P<0.05) at the Wagner location suggesting higher productivity under tilled conditions, the results are discounted because of overall poor medic performance resulting from drought (Table 1). The highest yielding treatment produced only 51 lb/acre DM forage. While at SAREC, where conditions were more typical, such differences were not noted (Table 2). Rik Smith, replaced Ron Delaney who retired. James Krall and Rik Smith will coordinate this effort the second year. The same trial was established as dryland and, because of the drought, an irrigated site was established at SAREC near Lingle WY in September of 2004. There was good emergence and establishment of medic at both sites. Objective (3). Identify pea lines for optimum winter survival, and forage and/or grain quality and yield. In 1999, Robin Groose produced F1 hybrids from 80 cross-combinations among diverse pea lines, including AWP cultivars, AWP Plant Introductions, as well as selected spring pea lines. F2 seed was produced in the greenhouse and 17,062 seeds were space-planted at Archer WY in fall 2000. Four hundred and eighty-nine selected F2 plants from among 3,292 winter survivors (19% survival, with some F2 families superior to existing cultivars) were single-plant threshed at maturity in summer 2001. Currently 168 F3 lines from 52 of the 80 original cross-combinations are being advanced to the F4 generation and for further selection among and within lines. Uniform lines will be further multiplied for seeding in 5ft by 20ft plots in replicated trials on cooperators’ farms and UW-SAREC sites and for nutritional analyses. Selected lines are either true-breeding or still segregating for various combinations of foliage traits (semi-leafless or ‘afila’, reduced stipules, leafless, acacia-type, etc.), indeterminate and semi-determinate growth habit, purple vs. white flowers (and pigmented vs. clear seedcoat), yellow vs. green cotyledon, and other economic traits. Selection nurseries were planted (autumn 2003) at UW-SAREC under irrigation at Torrington and dryland at Archer, WY. As expect further segregation for quantitative traits such as winter-hardiness, time to maturity, and forage and seed yield occurred. Selected lines were further advanced to plantings (autumn 2004) at UW-SAREC. Thus, with further selection these materials should generate productive, adapted pea lines of multiple market classes and for diverse uses on the Central High Plains. In 2005 six sites (4 with farmer cooperators, 2 at SAREC sites) will be used to demonstrate and evaluate advanced fall-planted pea lines. The cooperators are Theron Anderson, John Baker, Lou Hubbs, and Herb Mattson. One selection that demonstrated superior early spring forage production with upright stature is being fast-tracked into seed increase for possible release as a forage pea forage hay production. Under the direction of Bret Hess, samples of selected pea lines will be subjected to laboratory tests known to provide information regarding potential nutritive value for livestock. Objective (4). Determine nutritional and economic value of ‘dun’ and ‘white’ grain pea types. Seed of cultivars of these spring pea types will be evaluated in swine, sheep, and cattle experiments at the UW livestock feeding facility in Laramie. Bret Hess will coordinate this effort in year 2. Year 1 was a seed production year. Eight tons respectively of ‘dun’ and ‘white’ grain pea types were produced either under contract or at UW facilities for feeding trials commencing in the autumn. Cooperator Theron Anderson helped with this effort, which James Krall coordinated. Objective (5). Develop a protocol for biological control of weeds in chickpea for organic production. Stephen Miller will determine optimal bio-control practices for weeds in a chickpea field. Farmers in the Central High Plains are interested in decreasing fallow and developing a more intensive dryland cropping system. Many are interested in a legume because of the potential benefits they afford such as reduced fertilizer requirements, improved soil quality and improved pest management. Chickpeas (Cicer arietinum) is a grain legume that has caught their attention. Field studies were conducted in southeast Wyoming at the Archer and Torrington Research and Extension Centers in year 1 to evaluate weed control and chickpea response with herbicides or grazing sheep. Herbicide plots were 10ft by 30ft while grazed plots were 120ft by 130ft. Weed and crop response ratings were made two weeks after grazing or herbicide application. Chickpea tolerance varied widely depending on herbicide treatment and sheep stocking rate and utilization percentage. In general, chickpea exhibited good tolerance to the low stocking rate with 25% utilization or herbicide treatments containing trifluralin, ethafluralin, pendimethalin, dimethenamid and sulfentrazone. Together broad spectrum weed control ranged from poor to good (0 to 100% control of individual weed species) and was generally better with herbicide compared to sheep grazing techniques. Treatments containing trifluralin, ethafluralin, and sulfentrazone provided the highest level of weed control while post treatments containing imazethapyr, imazamox, pyridate, or bentazon provided the lowest level of control. Sheep grazing provided intermediate levels of control. This research will again be conducted at two sites in year 2 with modifications in herbicide and sheep grazing treatments.

Impacts and Contributions/Outcomes

Producers and investigators conferred during the development of both the pre-proposal, full proposal and during year 1. Boyd Yeik in WY and Robert Wagner in CO provided land, livestock, and equipment, as well as farming expertise. They helped monitor studies and gained experience in planting and managing of respective AWP and medic pastures. Although drought impacted both trials, both cooperators maintained a high level of interest. Mr. Yeik was impressed by how well AWP re-seeded itself raising the question of how this species might perform as a short-term ‘ley’ pasture species. Year 2 results should help to answer this question. Year 1 was too early for any formal dissemination of information via scientific journals, popular media, extension education programming, and field days. However the project has caught the attention of the national SARE office. The principal investigator will be interviewed in January 2005 for a potential article in a national SARE publication. Results from year 1 of objective 5 were presented at a regional professional meeting. In addition, the results of collateral study that examined yield and quality of winter-hardy M. rigidula line SA10343 at intervals over spring were presented at an international professional meeting. A scientific journal manuscript on this subject is in preparation.

Collaborators: