Final Report for SW03-008
In the drought, the large seeded legume AWP constantly established. The smaller seed medic was much more variable in establishment regardless of the establish method under the drought conditions that persisted over the period of the project. Results from grazing sheep to control weeds in chickpeas were variable. A highlight is the finding regarding the feeding of two different classes of grain pea to livestock. Results indicate that discounting Forager “dun” pea grain based on livestock feed value is not justified. Further investigation of large seeded legume forages and bio-control grazing for weed control in chickpeas is proposed.
Our overall goal is to further develop annual legume-based systems for the economical integration of crop/livestock enterprises. Specific objectives are:
(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’ grain pea types.
(5) Development of protocol for biological control of weeds in chickpea for organic production.
Field study components are aimed at educational outreach as plot tours will be held at each field site. Thus, experimental plots also serve as demonstration sites. All objectives address information outreach to producers.
Most dryland cropping systems on the Central High Plains still include fallow, which diminishes economic and ecological sustainability. Although the 14-month fallow associated with the traditional winter wheat-summer fallow system (WW-SF) has generally guaranteed successful wheat seedling establishment, the system is notoriously inefficient. Usually less than 25% of the precipitation received during fallow is stored in the soil for the subsequent wheat crop, and only one crop is harvested every two years. Weed control with tillage leaves a bare soil surface during the latter part of the fallow and into the wheat seedling growth period, which intensifies both wind and water erosion. Furthermore, tillage stimulates soil organic matter (SOM) losses compared to annual cropping resulting in a need for supplemental N for cereal crops (25). Unfortunately, even no-till WW-SF is still inefficient in terms of water conservation (approx. 40% utilization; 39). By substituting herbicidal weed control for tillage, farmers can decrease erosion, but this usually increases costs and the net result can be less profitable than conventional tillage fallow systems (35, 41). Inefficient water use in both tillage and chemical fallow systems can reduce water quality. As much as 55 ppm nitrate has been reported in groundwater beneath crop/fallow cultivated land (17). In summary, adverse effects of fallow include lower profit potential, decreased SOM, declining soil fertility, inefficient use of the water resource, root zone leaching of nutrients, soil erosion, air pollution, and surface and groundwater pollution (40).
More intensive agroecosystems might solve these problems by partially or completely replacing fallow. More intensive crop rotations might increase returns, reduce overall, long-term financial risk, and decrease erosion (18). Integrated dryland crop and livestock agroecosystems are agriclimatic zone-specific, and represent a potential ecologically and economically sustainable form of agriculture (30). Thus, there is a need to identify and develop appropriate legume/cereal/livestock systems that fit the natural resource base. This project is designed to capitalize on the widely recognized N-fixing and soil quality-building attributes of annual legumes to meet the WSARE goals of enhancing environmental quality and the natural resource base, making efficient use of nonrenewable and on-farm resources, and integrating natural cycles and controls while sustaining economic viability and satisfying food and fiber needs.
We are inspired by successful Australian dryland agroecosystems that utilize annual pasture and grain legumes to integrate cereal and livestock production (3, 13, 16, 47, 51). In Australian “ley farming” systems, annual legume pastures profitably and ecologically integrate cereal crop and livestock production to form the foundation for flexible and sustainable semi-arid lands farming systems (13, 12, 16, 47, 51). Medic (annual Medicago spp.) pasture alternates with wheat in much of semi-arid southern Australia. Annual medics regenerate yearly from a soil seed bank, and in the pasture phase of the cropping sequence provide forage for sheep and cattle. In the cereal phase of the cycle, regenerating medics may briefly furnish forage before seedbed preparation for planting wheat or barley. Today, annual medics are the principal legume component on more than 50 million acres in the “wheat-sheep” zone of southern Australia where they have largely replaced fallow to provide myriad benefits to Australian agriculture (13, 16, 47, 51), which include more profitable cereal production (8); high-quality livestock forage (33); self-regenerating pastures from a soil seed bank (16, 21, 49); integrated pest management with a better break to cereal pest and disease life cycles than provided by fallow and weed suppression by medic swards (32); reduced fertilizer inputs (22, 49); increased plant and field water use efficiency due to better plant nutrition, more intensive rotations, and improved soil water-holding capacity (14, 48); improved air and water quality (43); soil conservation and improved soil quality (13, 15, 16); no need for strip farming allowing more efficient use of large machinery and fencing (41); and the potential global benefit of C-sequestration as related to the higher primary productivity of ley farming and reduced SOM oxidation relative to fallow systems.
Grain legumes also benefit cereal production systems in Australia. For example, Angus et al. (3), in a review of long-term cereal/grain legume rotation studies, reported a 40-50% yield gain for wheat growing after grain legumes compared to wheat after wheat. In fact, grain legumes offer most of the advantages of ley pastures, except that they must be seeded whenever included in the cropping sequence (no self-regeneration) and they may not build soil as effectively as pasture. Still, like medic pastures, grain legumes grown for animal feed serve to integrate livestock and cereal production within the farming enterprise, and edible grain legumes (pulses) are especially valuable for direct human consumption. Moreover, large-seeded legumes offer greater seedling vigor, more reliable establishment and more flexibility as to when to incorporate them into a cropping sequence.
Annual legumes in rotation with cereals might similarly sustain agriculture on the U.S. Great Plains. To this end researchers at the University of Wyoming have cooperated with producers to identify viable annual dryland legume cropping options. Results are promising, but more work must be done before annual legumes become prominent across the Central High Plains landscape. Thanks to funding by WSARE (SW98-071), we have shown that a winter annual legume/sheep grazing agroecosystem (with Austrian winter pea, ‘AWP’; Pisum sativum ssp. arvense) might produce more than twice the profit of conventional wheat/fallow as lambs gained >0.5 lb/day grazing pea pastures and subsequent wheat crops were higher in protein compared to wheat after fallow (11, 24, 27). The present proposal will include grazing studies with cattle (Objective 1), more important than sheep on the U.S. Central High Plains.
After extensive evaluations of diverse annual medics (50), we determined that M. rigidula (a species found at high latitudes and elevations in Eurasia, and neither naturalized nor commercialized in Australia) is a promising candidate for winter annual regenerative pasture on the Central High Plains (45, 46). This species carries the necessary winter survival potential and seed survival and staggered seed-softening for our environment (27, 28, 50). An especially valuable characteristic of this species is that is effectively nodulated by readily available commercial alfalfa rhizobia (23). However, establishment practices must be optimized to maximize winter survival ensure long-term pasture regeneration (Objective 2).
Changes in the USDA farm program have stimulated interest in dry peas (both AWP and P.s. ssp. sativum, ‘garden pea’) to be grown for grain for livestock feed and direct human consumption as dry green and yellow split peas. (We emphasize that with passage of the new five-year farm bill that our proposal is of even greater economic significance and WSARE relevance than when first submitted as a pre-proposal.) Both AWP and edible peas offer attractive options for producers if locally-adapted cultivars can be adopted into Great Plains farming enterprises. Fortunately, we have already made many hybridizations within and between pea subspecies, and have gone on to make selections from a fall-seeded, summer harvested F2 space-plant nursery to identify winter-hardy peas for forage and grain production (and possibly for dual- and even triple-use depending on growing season and market conditions). Selected, diverse F3 lines are being advanced for agronomic evaluation and determination of grain feed value, including identification of any anti-nutritional factors (31, 19; Objective 3).
Also, field trials have established the yield potential of spring-planted ‘dun’ and ‘white’ grain pea types (7, 29). We are producing large quantities of seed of these pea types for feeding trials with beef, sheep and swine (Objective 4).
Chickpea (Cicer arientinum) is also included as a program crop in the new USDA farm bill and might capture an important niche as a grain legume in conventional and organic production systems on the Central High Plains. Piper (42) reported that in Australian trials chickpea could be lightly grazed by sheep to reduce the level of weed infestation because young chickpea leaves contain organic acids that sheep avoid. In 2001, we conducted a limited 6 sheep/3 hour graze of chickpea infested with Russian thistle and observed a distinct animal preference for the Russian thistle, an especially troublesome in weed in the WW-SF. Thus, inclusion of chickpea and livestock in wheat production might serve to reduce infestations of thistle without herbicides, offer all the other benefits of a legume in the rotation, and integrate crops and livestock, perhaps in an organic production system (Objective 5).
These various efforts could all lead to sustainable annual legume-based systems, and research with diverse pasture and grain legumes should provide useful comparative results. In summary, we propose to fill current knowledge gaps over the next three years with the goal of expanding annual dryland legume production and integration of livestock into cropping systems on the Central High Plains.
Objective (1). Expansion of the Austrian winter pea grazing/wheat system to encompass beef production. A cooperator-based field demonstration trial will be used to compare the economic return of grazed wheat stubble to wheat stubble containing post wheat harvest planted pea. James Krall will coordinate this effort, which will be repeated a second year, and Boyd Yeik is the farmer cooperator. Cattle normally graze two 6 acre fallow (wheat stubble containing weeds and volunteer wheat) strips adjacent to the home place. Each strip will be divided into two equal sections and equal numbers of sections will be seeded to inoculated AWP the end of August at the rate 60 lb/acre or left as fallow. A preliminary dryland AWP grazing study conducted in 2000 indicates that 2 AUM/acre is an adequate stocking rate. Therefore, to make a replicated study, six randomly selected cow/calf pairs will have free access to each AWP pasture section and six individual cow/calf pairs will have free access to each fallow pasture section. The four lots will be compared by weighing cattle at the start and again at the end of the grazing period. The grazing interval will run from the first part November until 75% AWP utilization. Depending on the season it may be possible to graze in the fall and again in the spring. Exclosures will be placed in each section to determine utilization of weeds, volunteer wheat, and AWP by cattle. Utilization will be determined by height measurements, harvested samples and visual estimation. Effect on the subsequent wheat crop will be monitored by sampling for yield and protein in the previously grazed AWP/fallow and fallow sections.
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. This will be accomplished by first developing enterprise budgets, showing per unit costs and returns for alternative crop and livestock enterprises. The development of individual crop budgets will use the same format and procedure used by Agee (1) for estimating costs of producing dryland wheat in Southeast Wyoming. Specifically, input and machinery costs for respective field operations will be computed throughout the production cycle (considering both traditional versus new alternative crops in the rotation) with a computerized cost generator (10). At the next stage, individual enterprise budgets will be consolidated into a multi-year whole-farm simulation model to account for potential year-to-year cost and yield interrelationships, similar to a previous simulation model (26). In addition to evaluating each system with respect to single-point estimates of profitability, the corresponding impacts of year-to-year product price and yield variation with each respective system, will be examined in the context of appropriate probability distributions with a monte carlo @RISK simulation approach. The economic analysis will be completed on the pea rotations during the grant period. This analysis will also provide the framework for future evaluation of the annual medic rotations.
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 will be 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; 50) for long-term pasture ‘ley’ production. The study will consist 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 will be replicated four times and measure 10 ft by 30 ft. The M. rigidula seed will be inoculated with Rhizobium inoculant and sown at the rate 6 lb/acre pure live seed. Sowing will take place in mid-August (a previously determined optimum planting date; 50). Establishment will be measured by visual rating and seedling emergence counts at 60 days after sowing. Level of winter survival will be determined the following spring be visual rating, plant counts, and forage biomass and seed production. James Krall and Ron Delaney will coordinate this effort which will be repeated a second year.
Objective (3). Identification of pea lines for optimum winter survival, and forage and/or grain quality and yield. 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.
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 (4, 5, 6, 15, 34, 44). F2 seed was produced in the greenhouse and 17,062 seed were space-planted at Archer WY in fall 2000. 489 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-SCAREC 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 (4, 15,). We expect further segregation for quantitative traits such as winter-hardiness, time to maturity, and forage and seed yield. Thus, with further selection these materials should generate productive, adapted pea lines of multiple of market classes and for diverse uses on the Central High Plains.
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. Forage and grain samples will be analyzed for dry matter and ash (2), crude protein (Leco FP-528), and digestibility (Filter bag technique; DaisyII digestion system). Forage samples will be analyzed for neutral and acid detergent fiber (Filter bag technique; Ankom200 analyzer), whereas grain samples will be analyzed for starch using a modification of the MacRae method.
Objective (4). Nutritional and economic value determination 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 two. For the swine feeding project, 60 grower pigs will be equally allotted to receive one of three diets (20 pigs/trt). Peas will be compared to a conventional corn-soybean meal ration, where an appropriate proportion of corn and soybean meal will be replaced by the respective grain pea type. Initial samples of each pea type will be subjected to quality analysis (including amino acids) to determine the appropriate level of corn-soybean meal replacement. Rations will be formulated to meet the nutritional recommendations of the NRC (37). Hogs will be group-fed in pens with no less than two pens per treatment group. Following a 45-day growing period, rations will be reformulated and fed for an additional 75-day finishing period. Performance measurements to be determined throughout each phase of the experiment include average daily feed intake and gain, as well as feed and gain efficiency. Following weaning, 60 Western white-faced lambs will be placed in 1.0 1.5-m pens within a slatted-floor barn. Lambs will initially have ad libitum access to hay and will be gradually switched to a corn-soybean meal-based diet formulated to achieve 0.75 kg/d gain (36). After adjusting lambs to the new diet, lambs will be blocked by body weight, and within block, randomly assigned to a pen (two lambs/pen) with each pen randomly assigned to one of three dietary treatments (10 pens/treatment). Each pea type will replace a portion of the corn-soybean meal to provide isonitrogenous and isocaloric rations. Feed refusals will be collected weekly and stored for later analysis (see Objective 3). Feed refusals will be used to adjust the daily amount of feed offered the subsequent week, ensuring minimal refusals, and to determine daily intake. Body weights will be obtained before feeding on two consecutive days every 20 and 21 days and at the end of the 130-day feeding trial. The average 2-day weight will be used to determine gain and final body weight. Developing replacement heifers will be used for the cattle experiment. Beginning 90 days before the breeding season, 90 heifers will be grouped by body weight and randomly allotted to one of twelve pens, where dietary treatment will be imposed. Pens will be equipped with feed bunks and self-waterers. All heifers will have free access to long-stem bromegrass hay and trace-mineralized salt. One of three dietary supplement treatments will be delivered to each pen. A corn-soybean meal control supplement will be compared to a supplement containing one of the two pea types. Again, supplements will be formulated to be isocaloric and isonitrogenous and to provide body weight gains of 0.91 kg/d (38). Hay intake, growth, and reproduction responses will be determined as previously described (9, 52). Subsamples of each diet will be collected daily throughout each experiment. These samples will be composited before being analyzed as described for Objective (3). Next, Larry Held will coordinate the evaluation of the economic effectiveness of incorporating grain pea types into swine, sheep, and cattle rations with the traditional soybean meal-based ration. Methodologies as described in Objective (1) will be used. The economic analysis will be completed during the final year of the grant period.
Objective (5). Development of protocol for biological control of weeds in chickpea for organic production. Stephen Miller will determine optimal bio-control practices for weeds in chickpea a field study to be conducted at the UW-SAREC over two years, consisting of two lamb stocking rates (7 and 14 lambs per acre), two grazing intervals (25 and 50% chickpea utilization), a standard herbicide treatment and an untreated check. The herbicide treatment and the untreated check will be used as a basis for comparison for the grazing treatments. Plots will be replicated four times and measure 100 ft by 200 ft. Rhizobium-inoculated ‘Dwelley’ chickpea seed will be seeded at a rate of 3 plants/sq ft. Grazing will begin approximately 4 weeks after chickpea emergence. Exclosures will determine utilization of weeds and chickpea by lambs. Utilization will be determined by height measurements, harvested samples and visual estimation. The herbicide treatment will be a preplant incorporated application of pendimethalin plus sulfentrazone at 2 pt/acre and 2.67 oz/acre. Weed control will be rated 2 weeks after grazing treatment and again 60 days later. Weed biomass samples will be collected at the time of the 60 day evaluation. Grain yield will also be determined for each treatment.
For all objectives, methodologies are well-established techniques for agronomic research, plant breeding, forage and feed grain quality evaluation, and economic analysis. We anticipate no pitfalls beyond the normal vagaries of weather involved in field research. Although this research primarily focuses on legumes for dryland agroecosystems, some plant genetic materials are being increased under irrigation to ensure that sufficient quantities of seed are available for experimentation, even during the present severe, long-term drought.
4. Producer involvement: Producers and investigators conferred during the development of both the pre-proposal and full proposal. Producers will provide land, livestock, and equipment, as well as farming expertise. They will help monitor studies and make sites available for public field tours.
5. Outcomes: a. This project will increase producer knowledge as cooperators grow and utilize new annual legume pasture and crop plants. They as well as other regional producers will have access to results via visual assessment during field tours, grower meetings and publications. Knowledge gained will guide Central High Plains producers in the adoption of new legume crop/pasture plants and conversion to more intense and integrated crop/livestock production systems. b. Information will be disseminated via professional meetings, scientific journals, popular media, extension education programming and field days. c. The measurable number of acres or animals that will be impacted may both be measured in the hundreds of thousands. Today, alternative crops such as sunflowers and proso millet replace 20-25% of fallow in Wyoming. Annual legumes might exceed this level of production. An especially important animal impact of legume pastures is to reduce confined feeding. d. The measurable economic impact to farm and ranch families and communities is impossible to predict precisely. In fact, this research is designed to generate data to more precisely measure that impact. So far, our economic analysis of grazed AWP in place of fallow favors the replacement of fallow with a return of an extra $8/acre (24). Based on a 20-25% fallow replacement this means an additional $320,000 to $400,000/yr for the agricultural economy of southeastern Wyoming alone. Adoption of these practices in adjacent states would result in substantially larger returns.
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Objective (1). Expand the Austrian winter pea (AWP) grazing/wheat system to encompass beef production. In the autumn of 2003 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 2004 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.
Later in 2004, Mr. Yiek reported that he had “a fine-looking field of AWP that had volunteered from seed”. He left them through the winter for there green manure value, and as a break from wheat. Latter he reported that this seemed to be helping with downy brome control.
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 establishment was acceptable using standard small grain equipment both years, but during an extremely dry year it failed to produce enough spring growth to warrant grazing. In a more normal moisture year heifer performance on AWP equaled that of perennial range pasture.
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. In 2003 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. The highest yielding treatment produced only 51 lb/acre DM forage. While at SAREC, where conditions were more typical, such differences were not noted.
In 2004 Rik Smith, replaced Ron Delaney who retired. The same trial was established on 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. 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 was repeated in 2005-06 as trials were established at both sites in the autumn of 2005.
The period from September 2005 to August 2006 was the driest on record. The precipitation over this period was approximately 25% of the long term average. While no till did (p>0.05) improve establishment under on dryland (4 and 6 plants/m2 for till and no till respectively), the level of establishment for both methods was unacceptably low. Irrigation improved the establishment with no till producing significantly (p>0.05) higher plant populations (22 and 67 plants/m2 for till and no till respectively). An important results is that establishment of Medicago rigidula is very soil moisture dependant. Establishment methods did not constantly over come the effect of dry autumns. Medic pastures in the Mallee region of Australia have experienced a similar fate in resent year where under dry conditions the sowing of larger seeded legumes such as pea and vetch at greater depth into the soil moisture zone has proven to be more dependable. However the project PI, who just returned from this region, observed excellent medic pasture production fallowing the exceptionally wet autumn in the Mallee region. Medic pasture seeded decades earlier had self sown and were flourishing.
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. A total of 168 F3 lines from 52 of the 80 original cross-combinations were 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 were 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. 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. 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.
Objective (4). Determine nutritional and economic value of ‘dun’ and ‘white’ grain pea types. 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 Mike Peterson of Albin, WY helped with this effort, which James Krall coordinated. Seed of cultivars of these spring pea types were evaluated in swine, sheep, and cattle experiments at the UW livestock feeding facility in Laramie. Bret Hess coordinated this effort. 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). Develop a 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. 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. Results from a dryland site in year 1 looked especially 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.
In summary, results from grazing sheep to control weeds in chickpeas were variable. A recent media report claimed that sheep could be taught to prefer weeds over grape leaves by using lithium chloride. This approach should be attempted in the development of a protocol for using sheep to control weeds in chickpeas.
Producers and investigators conferred during the development of both the pre-proposal, full proposal and during the project. 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. The new cooperator Mike Peterson was impressed at how much better his corn looked following the production of peas compared to winter wheat. Results from biocontrol of weeds in chickpea 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.
The medic establishment experiments were a featured stop at several annual SAREC (Lingle, WY) summer field days. Approximately eighty people listened to Jim Krall discuss the experiments. Robin Groose spoke during one field day at the pea selection nursery about progress being made in the development of winter annual peas. Additionally, there has been a release of a variety of Medicago rigidula. A variety release application was approved by the UW variety release committee. The variety will be marketed under the trade market name of ‘Laramie.’ A scientific journal manuscript has been published on this new medic variety. Jim Krall accepted an invitation to speak on ‘Ley’ farming at the WSCS meetings in Bozeman, Mt. A Master of Science thesis, under the direction of Larry Held, was completed in 2005 which examined 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. Larry Held has drafted a scientific journal manuscript on this subject. Papers were prepared, under the direction of Bret Hess, and presented at the WASAS meetings and published in the proceedings on the results from the livestock pea feeding trials. Steve Miller, directed the development of an article on the chickpea research, that was recently published in the UW-AES annual capstone magazine titled ‘Reflections.’ He also directed the graduate student thesis that was completed on this topic of research. A multi-state pea production guide was published in 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.
Education and Outreach
Krall, J. M., J. Nachtman, and J. T. Cecil. 2004. Performance of Medicago rigidula (WY-SA-10343) over two springs in Southeastern Wyoming. Second Australian New Crops Conference.
Krall, J. M., and R. Groose. 2005. Research into 'Ley' Farming: the Wyoming Experience. Abstracts Western Society of Crop Science. American Society of Agronomy
Wolf, A., E. J. Scholljegerdes, J. Krall, S. L. Lake, and B. W. Hess. 2005. Growth Performance and Carcass Characteristics of Finishing Hogs Consuming ‘Dun’ or ‘White’ Field Peas. Proceedings, Western Section, American Society of Animal Science. Vol. 56.
Mbugwa, G.w., J. Krall, and D. Legg. 2006. Optimum Establishment Practices for Medicago rigidula in the Central High Plains. Gatua wa Mbugwa, James Krall, and David Legg. Abstracts Western Society of Crop Science. American Society of Agronomy
Bagley, J., J. M. Krall, and B. Hess. 2006. Forage Production, and Quality of Potential Ley Species for the Central High Plains. Abstracts Western Society of Crop Science. American Society of Agronomy.
Price, P. L., J. M. Krall, S. L. Lake, T. R. Weston, V. Nayigihugu, and B. W. Hess. 2006. Growth Performance and Carcass Characteristics of Lambs Fed Carnival or Forager Field Peas.
Proceedings, Western Section, American Society of Animal Science. Vol. 57.
B. W. Hess, J. M. Krall, B. K. Stevens, S. L. Lake, T. R. Weston, and V. Nayigihugu. 2006. Growth and Reproductive Performance of Beef Heifers Fed Carnival or Forager Field Peas. Proceedings, Western Section, American Society of Animal Science. Vol. 57.
Krall, J. M., S.D. Miller, J. T. Cecil, C. Bastian, T. Foulke, D. D. Baltensperger, B. M. Harveson, P.A. Burgener, G. W. Hergert, G. L. Hein, D. J. Lyon, T. Nleya, J. Rickertsen, and S. Blodgett. 2006. Pea Production in the High Plains. UW EC B1175.
Kniss, A., R. Rapp, J.Krall, and S.D. Miller. 2006. Did somebody say gar-baaaaaa-nzo? UW-AES:Reflections 24-26.
Krall, J.M., R. W. Groose, M.J. Walsh, V. Nayigihugu, J.T. Cecil, and B. W. Walsh. 2007. Laramie Annual Medic. Journal of Plant Registrations 1:32-33.
Education and Outreach Outcomes
Areas needing additional study
Results from grazing sheep to control weeds in chickpeas were variable. A recent media report claimed that sheep could be taught to prefer weeds over grape leaves by using lithium chloride. This approach should be attempted in the development of a protocol for using sheep to control weeds in chickpeas.
Large seeded legumes, like pea and possibly vetch like the new soft seeded vetch variety ‘Morava’ from Australia, should be investigated for forage production. They hold the promise of establishing in the dry autumn conditions that seem to be becoming the norm for the region.