Background and Aims Agricultural phosphorus (P) management is essential for maintaining crop yields, but practices aimed at preventing deficiency often result in overuse and soil P saturation. The subsequent runoff contributes to eutrophication of nearby water bodies. Phytoremediation, using plants to absorb excess soil nutrients, offers a sustainable solution but requires engineering crops that hyperaccumulate P. Recent genetic studies show that mutations in the PHO2 -like genes, which help maintain phosphate (Pi) homeostasis, can result in substantial Pi hyperaccumulation in mutant plants. Methods In this study, mutated pho2 alleles from the six-haplotype mutant PhotM65-2 were introgressed into elite genotypes of tetraploid alfalfa ( Medicago sativa L.), resulting in seven F1 lines with mutations in PHO2 -like genes ( PHO2-B and PHO2-C ). The study characterized these F1 mutants, evaluated their Pi accumulation, and identified the most effective genetic combinations for Pi accumulation. Results Specifically, double and triple mutants with edits in PHO2-B and PHO2-C accumulated significantly more Pi than control genotypes under both high and low P conditions. Notably, some novel mutants maintained enhanced Pi content in their leaves without a biomass penalty. Conclusion This study demonstrates the successful introgression of CRISPR/Cas-edited PHO2-B/C alleles in alfalfa, identifying specific mutated pho2 allele combinations in F1 lines to create P-hyperaccumulator plants for remediating P-saturated soils and advancing agricultural sustainability.

Kernza intermediate wheatgrass (IWG) [Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] is a perennial grain and forage crop with novel dual-use potential. Grazing IWG forage and/or intercropping IWG with legumes can increase total annual forage yields, but the effect of grazing timing on grain yield needs to be understood to maximize producer returns and the productivity of the perennial stand. In this study, we compared Kernza grain and forage yields under different cattle grazing timing treatments (spring, fall, or spring and fall) with ungrazed IWG stands, in both IWG monocultures and IWG-legume intercrops. We established the experiment in the fall of 2016 at Morris, MN, and Lancaster, WI, and collected data over 3 years. In the first grain production year, grazing spring vegetative regrowth reduced Kernza grain yield compared with ungrazed stands in both Minnesota (213 vs. 360 kg ha-1, respectively) and Wisconsin (821 vs. 1030 kg ha-1, respectively). However, grazing fall regrowth after summer grain and straw harvest did not negatively affect grain yield in the following year compared to the ungrazed control. Intercropping IWG with legumes increased accumulated forage vegetative regrowth in Wisconsin, but not in Minnesota. Overall, our study confirms IWG's potential as a dual-purpose crop under grazing management and recommends fall grazing to minimize adverse effects on subsequent grain yields. Future research should focus on refining grazing strategies to maximize dual-use productivity.

Perennial crops may improve the environmental sustainability of agriculture through their continuous growth, low inputs, and high root biomass. Extensive root growth of perennial grass crops, especially, can confer benefits such as improved soil health and soil carbon (C) storage both directly through biomass production and indirectly through stimulating soil microbial communities. To test these ideas, we compared crop productivity (grain, vegetative, and root biomass), soil microbial abundance, and soil microbial activity across six cropping systems for three years (2017-2019). The six cropping systems included the perennial species intermediate wheatgrass (Thinopyrum intermedium (Host.) Barkw. & D.R. Dewey; IWG), alfalfa (Medicago sativa L.), and a biculture of both. Annual crop rotations included wheat, soybean, and corn (Zea mays). IWG monocultures produced an average of 7.4 Mg ha-1 of root biomass over three years, two to three times more than annual systems. Because of early spring and fall vegetative growth, IWG and alfalfa had higher canopy density for a greater duration of the growing season than annual crops. IWG also had higher soil respiration in 2017 and 2019. These growth attributes of IWG were translating to higher fungal and Gram-negative bacterial lipid biomass than alfalfa or annual crops in 2019, also the year of the highest general microbial growth. The abundant root growth, annual duration of growing period, and conducive environment for microbial growth under IWG systems indicates the potential for future C storage, which may be offset to a degree by increased soil respiration.

Purple coneflower (Echinacea purpurea Moench [L.]) is widely used as a health supplement and is cultivated for its production of bioactive phytochemicals. However, there is a lack of information on how agronomic planting designs and environment affect the phytochemical content of different coneflower tissues. Experimental plots were established at two locations in Minnesota to evaluate the effect of environment and agronomic planting design on the phytochemical profile of purple coneflower, as well as the relative content of several provisionally identified compounds. Root, stem, leaf, flower, and seed tissues were harvested, and extracts were analysed using liquid chromatography-mass spectrometry. The growing environment affected the levels of several caffeic acid derivatives in leaf, stem, and root tissue, but agronomic design had little to no effect on phytochemical content. Although all tissue types contained phytochemicals of medicinal interest, no single tissue contained the highest amount of all compounds with known bioactive properties, indicating that the most beneficial purple coneflower supplements may be the combination of several tissue types. Additionally, the phytochemical content of purple coneflower seed, which is uncommon in Echinacea supplements, was chemically similar to root tissue. Seed tissue, after additional evaluations, may be a suitable alternative for root in supplement mixtures.

Winter injury of alfalfa [Medicago sativa (L.)] in the northern United States decreases its economic and ecosystem benefits. Therefore, continued improvement in alfalfa cultivar winter survival (WS) is crucial for sustaining the productivity of this perennial crop. The North American Alfalfa Improvement Conference (NAAIC) standard test for WS recommends measuring the WS of spaced plants established in rows the previous spring. Measurement of WS of alfalfa grown in sward plots used by plant breeders would increase data collection and better reflect the potential for WS when grown in production fields. We conducted trials at seven location-year environments spanning from Wisconsin to South Dakota in the northern United States. These trials involved six check cultivars and followed protocols from the NAAIC standard test. The objectives were to determine (1) if WS and biomass yield assessment from sward plots were similar to those from the standard spaced planted row ratings and (2) if location-dependent environmental conditions affected the usefulness of alternative approaches for measuring WS. Estimation of WS using spaced plants and sward measurements was highly correlated, while correlations between the WS of the spaced planted rows and biomass yields were less. The number of locations required for spaced and sward plantings to determine cultivar differences was at least two, with four replications per location. Measuring WS from swards can enhance data collection and its relevance to on-farm alfalfa production, as sward plots serve a dual purpose by allowing both WS testing and evaluation of yield, making them a practical choice in comparison to the exclusive use of spaced plants in rows for WS testing. Availability of sward-plot WS descriptions of alfalfa cultivars will enhance decision making by producers.

Intermediate wheatgrass (IWG) is a cool-season perennial grass developed as a dual-purpose grain and forage crop. One barrier to adopting this crop is a lack of information on the effects of herbicides on IWG for grain production. An experiment was conducted to evaluate herbicide effects on IWG grain yield, crop injury, and weed control over 2 yr (2019 to 2021) at sites in Wisconsin, Minnesota, New York, and North Dakota. This evaluation included broadleaf herbicides registered for use on wheat: 2,4-D amine, clopyralid, MCPA, and a mixture of clopyralid + MCPA (all are categorized as Group 4 herbicides by the Weed Science Society of America). Each herbicide or mixture was applied at 1x and 2x the labeled wheat application rate to newly planted and established (1- to 5-yr-old) IWG stands in the fall or spring. Herbicides were applied during IWG tillering or jointing stages in the fall or during the jointing stage in the spring. Across site years, application timing, herbicide, and application rate showed no effect on IWG grain yield or plant injury. Broadleaf weed control ranged from 71% to 92% across herbicide treatments relative to the nontreated check at the Wisconsin site, whereas weed control at the Minnesota site was variable among treatments. At the New York site, herbicides were equally effective for broadleaf weed suppression, whereas weed pressure was very low at the North Dakota site and treatments did not affect weed cover. The results show that newly planted and established stands of IWG are tolerant to the synthetic auxin herbicides 2,4-D amine, clopyralid, and MCPA when applied during tillering or jointing in the fall or during jointing in the spring. Synthetic auxins represent a potentially useful tool for weed control in IWG cropping systems, especially for problematic broadleaf weed species.

Organic crop production is a growing part of the agricultural economy. The transition from a conventional to an organic cropping system, while complying with certification guidelines, is financially and logistically challenging for growers. Therefore, it is important to develop strategies, perhaps using novel cropping systems, that can both mitigate economic challenges and quickly improve soil health. We evaluated the impact of perennial and annual cropping systems on soil health during the first two years of a three-year organic transition period at three research stations in Minnesota distinct in climate and soil conditions: Rosemount, St. Paul, and Lamberton. The sites were established in fall of 2017 by planting each of six cropping systems including 1) the novel perennial grain crop intermediate wheatgrass (IWG), 2) alfalfa, 3) an intermediate wheatgrass - alfalfa intercrop (IWGAlfalfa), 4) a winter wheat - red clover (WheatRC) rotation, 5) a corn – soybean (SoyCorn) rotation and 6) a corn - soybean rotation with a cereal rye cover crop (SoyCCorn). We measured root biomass and soil physical, chemical, and microbial parameters to evaluate soil health under the different cropping systems over time. IWG and IWGAlfalfa were consistently among the systems with greater root biomass and larger water stable soil aggregates, while SoyCorn systems had the least. Other soil health variables had site specific responses, with Lamberton and St. Paul the most influenced by cropping systems. At St. Paul and Lamberton soil pH increased in IWG and SoyCorn, and soil K decreased under WheatRC and alfalfa. Labile C and total C and N were not influenced by the different cropping systems. At Lamberton, increases in the biomass of microbial groups including bacteria, fungi, and actinomycetes were observed in IWGAlfalfa. The improvement in some health parameters at one or more sites by IWG and IWGAlfalfa after 2 years of the organic transition period could translate into building longer-term soil health for subsequent organically certified crops, but this is dependent on local soil and other characteristics. It will likely require more time for cropping systems to affect other important soil health parameters such as soil C in the C-enriched loamy soils of Southern Minnesota.

Nitrate (NO3--N) leaching into groundwater as a result of high nitrogen (N) fertilizer rates to annual crops presents human health risks and high costs associated with water treatment. Leaching is a particularly serious concern on sandy soils overlying porous bedrock. Intermediate wheatgrass (IWG) [Thinopyrum intermedium (Host.) Barkw. & D.R. Dewey], is a perennial grass that is being bred to produce agronomically and economically viable grain, which is commercially available as Kernza®. Intermediate wheatgrass is a low-input crop has the potential to produce profitable grain and biomass yields while reducing NO3--N leaching on sandy soils compared with common annual row crop rotations in the Upper Midwest. We compared grain yields, biomass yields, soil solution NO3--N concentration, soil extractable NO3--N, soil water content, and root biomass under IWG and a conventionally managed corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] rotation for 3 years on a Verndale sandy loam in Central Minnesota. Mean soil solution NO3--N was 77–96% lower under IWG than the annual crop rotation. Soil water content was greater under annuals compared to IWG early in the growing season, suggesting greater water use by IWG during this time. Interactions between crop treatments and depth were observed for soil water content in Year 3. Root biomass from 0 to 60 cm below the soil surface was five times greater beneath IWG compared to soybean, which may explain differences in soil extractable and solution NO3--N among crops. With irrigation on coarse structured soils, IWG grain yields were 854, 434, and 222 kg ha−1 for Years 1–3 and vegetative biomass averaged 4.65 Mg ha−1 yr−1; comparable to other reports on heavier soils in the region. Annual crop grain yields were consistent with local averages. These results confirm that IWG effectively reduces soil solution NO3--N concentrations even on sandy soils, supporting its potential for broader adoption on land vulnerable to NO3--N leaching.

Intermediate wheatgrass (Thinopyrum intermedium) (IWG) is a perennial grass being domesticated for grain production with potential to provide economic return and ecosystem services across a broad geographic range in North America, yet optimum seeding dates for grain and biomass yield are unknown. Our objective was to determine the effect of late-summer, fall, and spring seeding dates on grain and biomass yield of a grain-type IWG population. Trials were conducted at St. Paul and Roseau, MN, Kalispell, MT, and Salina, KS. Seeding dates ranged from August to June of the following year. Grain and biomass yields were highest when seeded at the earliest late-summer date for all environments except for Kansas, where a September 29 seeding date produced the greatest grain and biomass yields. Little to no grain was produced from spring seedings in the first production year, substantiating that photoperiod and vernalization requirements are needed for seed head induction. Grain and biomass yields were positively correlated to cumulative growing degree days (GDD) from seeding date to winter dormancy. A quadratic response was observed at Salina, KS, where seed yields maximized when GDD accumulation reached 912. Accumulation of vernalization units throughout fall, winter, and spring after seeding was also positively correlated with grain yield. The minimum vernalization units for grain production varied from 50 to 87 across sites. Results highlight important associations between thermal units and IWG grain yield when seeded in late summer; however, other variables affecting IWG seed head induction (e.g., photoperiod, snow cover) require further study.

Positive relationships between plant species diversity, soil microbial function and nutrient cycling have been well documented in natural systems, and these relationships have the potential to improve the production and sustainability of agroecosystems. Our objectives were to study the long-term effects of planted species composition and nitrogen (N) fertilization on soil microbial biomass C, extracellular enzyme activity, changes in total soil C, soil fertility and aboveground biomass yield in mixtures of native prairie species managed with and without N fertilizer for bioenergy production at four sites in Minnesota (MN), USA. Species were sown into mixture treatments and composition was not maintained (i.e., no weeding) throughout the duration of the study. Species mixture treatments at establishment included a switchgrass ( Panicum virgatum L.) monoculture (SG), a four-species grass mixture (GM), an eight-species legume/grass mixture (LG) and a 24-species high diversity forb/legume/grass mixture (HD). Species diversity and aboveground productivity were similar for most mixture treatments at final sampling after 11 or 12 years of succession. Despite this homogenization of productivity and diversity throughout the study, the effects of planted species diversity and a decade of succession resulted in some differences in soil variables across species mixture treatments. On a peat soil in Roseau, MN, soil enzyme activities including β-glucosidase (BG), cellobiohydrolase (CBH) and phosphatase (PHOS) were highest in HD compared to GM treatments. On a sandy soil at Becker, MN, total soil C increased in all treatment combinations at the 0–15 and 15–30 cm depth intervals, with SG showing greater increases than HD at the 15–30 cm depth. Final soil pH also varied by species mixture at the Becker and Roseau sites, but differences in treatment comparisons varied by location. Nitrogen fertilization did not affect any response variable alone, but interacted with species mixture treatment to influence PHOS and total soil C at Becker. The inconsistent effects of species mixture and N fertilization on soil biological and chemical properties observed across sites highlight the importance of local soil and climate conditions on bioenergy and ecosystem service provisioning of perennial bioenergy cropping systems.

Perennial grain crops are being developed to reduce the negative environmental impacts of tillage and chemical inputs related to annual row-crop agriculture. To further improve the ecological benefits of perennial grains like Kernza® intermediate wheatgrass (IWG) [Thinopyrum intermedium (Host.) Barkw. & D.R. Dewey], intercropping with perennial legumes has the potential to diversify grain production systems and reduce mineral N fertilizer requirements; however, the facilitative vs. competitive effects of various legume species on perennial grain yields are unknown. We compared grain and biomass yields, tissue C:N ratio, and δ15N of IWG in response to either mineral fertilizer treatments or intercropping with one of six legume species at three locations for three years. IWG tissue C:N ratio increased through time at all sites suggesting a consistent increase in N limitation. Although no legume intercrop consistently affected grain yields through time or across sites, very rarely did an intercrop reduce grain yields to levels less than fertilized and unfertilized IWG monocultures. However, legume biomass in year 1 was negatively correlated with IWG grain yields in year 1, suggesting that negative effects of competition may outweigh positive effects of N fixation and transfer the year following establishment. The relationship between legume biomass and IWG grain yield became positive by year 3, indicating a potential lag in the positive effects of legume intercrop on grain yield. At one location, red clover (Trifolium repens L.) biomass was higher than all other legume treatments in year 1 and declined through time, giving way to a subsequent increase in IWG biomass and grain yields through time. At this site, N transfer from legumes to IWG determined by δ15N was positive by year 3 for red clover and two other legume species. This study provides evidence that legume intercrops can benefit IWG production under certain conditions, but outcomes are site-specific and may depend on conditions related to soil N levels, temperature and precipitation patterns, and weed pressure. Research is needed to identify specific traits that promote legume coexistence and facilitation with IWG, and how these traits might rank in importance depending on environmental conditions.

Intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey; IWG) is a perennial sod-forming grass undergoing domesticated for use as a dual-use grain and forage crop with potential environmental benefits. IWG plant populations increase with stand age, which has been associated with reductions in grain yields after the second production year, thus management techniques are needed to maintain grain yields over time. We measured the effects of two between-row plant termination methods (cultivation and herbicide application) and two within-row suppression methods (burning and mowing), applied at different IWG physiological stages during the growing season. We measured IWG grain and straw yield, root biomass, and weed biomass. Treatments were initiated after the second year of grain harvest and applied for two consecutive years in southeast Minnesota. Grain yields were highest in production year 2 preceding any treatment application and declined in years 3 and 4 by 82% and 57% compared to year 2, respectively, across all management treatments. Termination methods reduced between-row IWG biomass and grain by up to 82% and 91% compared to the control but had no effect on within-row or total grain yield. Fall burning suppression treatments mitigated the negative effects of some termination treatments on grain yield and increased total straw yield. Spring mowing suppression treatments reduced grain and straw yield by 42% and 34%, respectively, compared to the control. Controls had minimal weed biomass while the termination treatments increased weed biomass, especially termination treatments that included herbicide application. No treatments sustained grain yields, but positive effects of some treatments were observed on total biomass and weeds and could be considered by growers.

Fireweed ( Chamerion angustifolium (L.) Holub.) is utilized worldwide in traditional medicine, due to its high levels of phenolic compounds that possess bioactive properties with a wide range of therapeutic effects on human health. However, there is little work on the direct production of fireweed for these beneficial phytochemicals. To examine the effects of nutrient availability on fireweed biomass production and metabolomic profile, fireweed plants were grown in a hydroponic greenhouse system with varying concentrations of Hoagland’s nutrient solution. As the concentration of the nutrient solution increased, shoot dry mass increased, and root:shoot ratio decreased. Variation in untargeted metabolomic profiles were detected in leaf, stem, and root tissues of hydroponically produced fireweed in response to nutrient level. Several metabolic features were identified, most notably the therapeutic compounds oenothein B and miquelianin. Relative abundances of oenothein B and miquelianin were largely unaffected by nutrient treatments, while several other phytochemicals increased in abundance as nutrient content decreased. This work demonstrates the potentiality of hydroponically cultivated fireweed to supply raw material for phytochemical demand, but the effects of mineral nutrient amendment must first be reconciled with biomass production.

Abstract Intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & Dewey] (IWG) is a perennial forage grass being domesticated to function as a perennial grain crop. Grain yield of improved, grain‐type IWG cultivars decline by the third year of production and managing aging stands for forage production presents economic opportunities. Limited research is available on the response of second‐ and third‐year grain‐type IWG to different forage harvest schedules. We measured forage yield and nutritive value of grain‐type IWG in the second and third year of production under nine forage harvest schedules varying in the timing of the first harvest (at boot, anthesis, or soft dough stage) and the number of fall harvests (none, one [Sept.], or two [Sept. and Nov.]). As timing of the first harvest was delayed and IWG maturity increased from boot to soft dough, yield increased from 2.4 to 3.7 Mg ha–1 and relative feed value decreased from 113 to 82. Yield at subsequent September and November harvests averaged 30% and 12% of the initial harvest yield, respectively. Total annual forage yield was not affected by the timing of the first harvest but was predictably greater for two or three harvests compared with one harvest; however, additional harvests in September and November decreased net returns. Grain‐type IWG stands harvested in the third year after peak grain production have potential to provide forage similar to common perennial cool season forage grasses. Tradeoffs between forage yield and nutritive value should be considered when selecting the timing of the initial spring forage harvest.

Abstract Forage yield, nutritive value, and stand persistence are key metrics in alfalfa (Medicago sativa L.) management. The combination of cultivar improvement, longer growing seasons in the Midwest, and trends of shorter alfalfa rotations offer opportunity to reevaluate the effects of increasing cutting frequency (CF) on these metrics. We evaluated forage yield, nutritive value, milk production, and persistence of eight alfalfa entries with fall dormancy (FD) ranging from two (FD2) to five (FD5) under CF of four (CF4), five (CF5), or six (CF6) annual cuts during two production years in two environments in the upper midwestern United States. Nutritive value and milk kg–1 alfalfa increased with increased CF and differed among alfalfa entries. Cutting frequency and alfalfa entry interactively influenced forage yield and milk production ha–1 yet optimal CF depended on environment. At one environment, increasing CF from CF4 to CF5 and from CF5 to CF6 caused a 5 and 29% decrease in milk ha–1, respectively. At another environment, CF5 had about 16% greater milk production than CF4 and CF6. The CF6 reduced persistence of 3rd‐year stand density with the effects especially severe for some entries. Alfalfa entry FD was not correlated to forage yield or persistence, but an entry with FD5 was consistently among those with the greatest in forage and milk yield ha–1 at CF5 and CF6. These results suggest that intensifying CF from four to five harvests per season of some cultivars can boost yield and nutritive value without negative effects on stand persistence in some environments.

Intermediate wheatgrass (IWG) [Thinopyrum intermedium (Host) Barkworth & D. R. Dewey subsp. intermedium] is being domesticated as a perennial grain crop. Advanced grain-type IWG populations display variability in key physiological parameters related to seed development, making it difficult to determine grain harvest timing. A quantitative literature review of cool-season grasses informed the modeling of IWG field trial data. Results revealed that multiple species exhibited a consistent multiphase dry-down pattern from anthesis to a stabilized moisture content, which often included a rapid dry-down phase that presaged maximum seed dry matter and gave insight into the relationship between floret shatter and maximum seed yield. A field trial was conducted at three locations in which IWG spikes were repeatedly sampled postanthesis and divided into three fractions to measure physiological patterns over growing degree days (GDDs). Similar to literature review results, IWG demonstrated a rapid dry-down phase that started when seed moisture content was between 44.7 and 52.8% and decreased at a rate of -0.12 to -0.20% GDD(-1) during this phase. At all locations, florets began shattering before seeds reached maximum dry matter, which resulted in reduced floret site utilization. Seed from distal fractions reached 95% dry matter 135 GDDs earlier than seed from basal fractions, while basal seeds were 21% larger than distal seeds. Timing of maximized seed yield per spike ranged from 530 to 701 GDDs after mid-anthesis provided a starting point for estimating optimum IWG seed harvest timing under high and low shattering conditions and also supports the importance of repeated measurement of seed moisture to pinpoint optimal harvest time.

Although contributions of the equine gut microbiome to forage utilization are well recognized, the impact of alfalfa (Medicago sativa L.) lignification on the equine gut microbiome remains unknown; thus, we characterized microbial communities in the equine gut when feeding reduced lignin (RL) and conventional (CON) alfalfa hays to adult stock-type horses. Dietary treatments were fed to six horses in a crossover study. Experimental periods consisted of a 9-day dietary adaptation phase followed by a 5-day total fecal collection phase, during which horses were housed in individual box stalls and manure was removed on a continuous 24-hour basis. At 12-hour intervals, manure was mixed, frozen, and processed for V4, 16S rRNA amplicon MiSeq sequencing. Reduced lignin alfalfa did not shift microbiome composition equally across all horses; however, each subject's microbiome responded to hay lignin content in an individualized manner, mostly, in terms of beta diversity. Amplicon sequence variants affiliated to Akkermansia, Fibrobacter succinogenes, Treponema, and Paludibacter fluctuated significantly when RL alfalfa was fed, with abundance patterns unique to each horse. Horse-specific associations between individual gut microbiome traits and characteristics of the digested CON or RL alfalfa were also observed, mainly in regards to dry matter digestibility and mean fecal particle size. These results indicate that the horse gut microbiome responds in an individualized manner to changes in the amount of acid detergent lignin in alfalfa hay, potentially impacting several feed digestibility characteristics. The implications of these horse-specific responses to hay lignification, for metabolic health and performance, remain to be elucidated.

Sydney Schiffner, Research Technician⇑ The Land Institute, Oilseeds Division, 2440 E Water Well Rd, Salina, KS 67401

Cover crops are commonly used to provide environmental benefits and can extend the grazing season, but have not been explored in horse pastures. The objectives of this research were to evaluate forage mass, forage nutrient composition, and preference of annual ryegrass, winter rye, berseem clover, purple top turnip, and daikon radish under horse grazing. Cover crops were seeded in monoculture and mixtures in August 2018 and 2019 as a randomized complete block with four replicates and grazed by four adult horses. Prior to grazing, forages were sampled to determine herbage and root mass and nutrient composition. After grazing, forages were visually assessed for the percentage of removal on a scale of 0 to 100% to estimate preference. Data was analyzed using an analysis of variance and linear regression; significance was set at P ≤ .05. Berseem clover was the lowest producing forage (590 to 1,869 kg ha−1 dry matter; P ≤.001), while minimal differences in herbage mass were observed among the other cover crops. All forages met digestible energy (>2.17 Mcal kg−1) and crude protein (>19%) requirements for idle, adult horses. Berseem clover was most preferred (>73% removal) while turnip and radish were the least preferred (<19% removal; P ≤.001). Winter rye and annual ryegrass in monoculture and when seeded with berseem clover were moderately preferred (20%–68% removal). Placing a priority on preference, berseem clover, annual ryegrass, and winter rye appear to be suitable cover crops to extend the grazing season in horse pastures.

Abstract Alternative plant‐based protein sources are needed for supplementing or replacing fishmeal in formulated animal feeds. Alfalfa (Medicago sativa L.), a perennial legume, is grown worldwide as a high‐protein forage crop used primarily for dairy and beef cattle feeds. However, its utility as a protein source for feeding other farmed animals has great potential. Wet fractionation can provide several products that increase the value of the crop. The amount of alfalfa protein concentrate (APC) recovered from a fresh press filtrate was measured from several feedstocks: herbage of a nonlodging biomass‐type alfalfa, genetically modified reduced‐lignin alfalfa, and conventional alfalfa as well as from leaves of the biomass type fractionated at harvest. Additionally, five methods for APC recovery were compared. Approximately 854 kg of APC, 7,109 kg of press residue suitable as low quality animal feed, and 4.5 Tg of dry hay could be produced annually from a hectare of biomass‐type alfalfa. The amounts of APC recovered from a reduced‐lignin alfalfa and a conventional cultivar were similar. Acid‐based precipitation methods resulted in the largest recovery of APC, whereas heating produced the highest concentration of protein in the concentrate and highest concentration of methionine, lysine, and threonine. The percentage of fatty acids and sugars in the concentrate varied significantly by precipitation method. All methods resulted in low amounts of fiber in the concentrate. Our results indicate that a nonlodging biomass‐type alfalfa can produce high yields of APC and co‐products with fewer harvests than a conventional cultivar, which reduces costs and promotes crop productivity.