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Alfalfa (Medicago sativa L.) ‐ grass or alfalfa ‐ sainfoin (Onobrychis viciifolia Scop.) mixtures are commonly used for pastures in western Canada because of their high forage quality and their low risk of causing frothy bloat in grazing animals. However, the proportion of these two legumes declines in mixed forage stands over time. The objective of this study was to evaluate the effectiveness of selecting superior genotypes from clonally propagated alfalfa or sainfoin under plant competition in different growth environments. For this study, around 100 genotypes of each legume were cloned and transplanted into meadow bromegrass (Bromus riparius Relm.) or alfalfa swards at Saskatoon, SK and Lethbridge, AB, Canada in 2017. Genotype‐environment (G x E) interactions of alfalfa and sainfoin genotypes were analysed by an additive main‐effects and multiplicative interaction (AMMI) model. Significant variations in plant height, spring vigour and total dry matter yield (TDM) were observed for both species. Among the measured traits, plant height was a more highly heritable trait (H2 = .16 for alfalfa and H2 = .18 for sainfoin), while TDM was the least heritable (H2 = .08 for alfalfa and H2 = .04 for sainfoin). In the AMMI Analysis of variance for TDM, the genotype explained <12% of the variation for both species, suggesting a direct selection of yield would result in a low genetic gain. The biplot mean performance (Y) x weighted average of absolute scores from the singular value decomposition of the matrix of BLUPs stability index (WAASB) identified several promising genotypes with superior performance and stability across different environments that were selected for producing synthetic lines. However, the synthetic lines of both alfalfa and sainfoin did not consistently exhibit superior performance in mixtures compared to their respective check cultivars. [ABSTRACT FROM AUTHOR]

In Canada, new forage varieties need not undergo grazing trials before registration and sale. To evaluate the effect of grazing, six cool-season species including meadow bromegrass (Bromus riparius Rehmann), orchardgrass (Dactylis glomerata L.), sainfoin (Onobrychis viciifoila Scop.), and three alfalfa varieties (Medicago sativa L.) were established in monocultures and grass–legume binary mixtures in Saskatchewan, Canada. Forage treatments were randomly established within each of three 3.5 ha paddock replicates. In Year 1, 69 Bos taurus crossbred steers, and in Year 2, 149 steers were homogenously allocated to the three paddocks for the grazing trials. Alfalfa monocultures had the greatest (p < 0.05) pre-graze forage yields and crude protein content. Leaf area index was greater in alfalfa monocultures than in all other treatments (p < 0.01). Etiolated growth differed (p < 0.05) among binary mixtures but not monocultures. Alfalfa monoculture stands were preferred over grass monocultures and most grass–legume mixtures, and sainfoin was avoided relative to alfalfa. Killarney orchardgrass was the least productive and least preferred among forages evaluated. In summary, alfalfa monocultures had greater (p < 0.05) forage yields and quality than sainfoin monocultures, grass–legume binary mixtures, or grass monocultures. [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa L.) cultivars developed for improved digestibility by conventional breeding or genetic modification have not been evaluated in eastern Canada. This study compared yield, nutritive value, and profitability of two reduced-lignin genetically modified (GM) cultivars, three conventionally selected for low lignin or high pectin, and one population with improved stem degradability, with two commercially adapted cultivars as controls. Alfalfa was harvested at the early bud (intensive management) or early flower (extensive management) stage of development during the first post-seeding year at three sites and the second post-seeding year at one site. All cultivars/populations had similar annual dry matter (DM) yields, except for the lower DM yield (−20%) of the improved stem degradability population. Conventionally selected cultivars for improved digestibility did not differ from control cultivars for in vitro DM digestibility (IVTD) and neutral detergent fiber digestibility (NDFd). Reduced-lignin GM cultivars, however, had a greater IVTD and NDFd (+10%) and less lignin (−10%) than control cultivars at the same stage of development. Reduced-lignin GM cultivars under extensive management had similar NDFd and greater annual DM yield (+1 to 2 Mg DM ha−1), but reduced total digestible nutrients (−41 to 44 g kg−1 DM), in comparison to control cultivars under intensive management. Using partial budget analysis, the comparison of more digestible GM cultivars to the control cultivars resulted in an increase in annual farm net profits ranging from CAD$7.40 to $79.60 cow−1 year−1 depending on stage of development at harvest. Further investigations are needed to quantify the performance of dairy cows fed cultivars with improved digestibility. [ABSTRACT FROM AUTHOR]

Warmer than normal late fall temperatures may change standard fall harvest management of alfalfa (Medicago sativa L.) in western Canada. The objective of this study was to evaluate the forage yield and nutritive value of three types of alfalfa cultivars under different harvest managements. A field experiment was conducted from 2013 to 2017 using rhizomatous type (RR), cv. AC Yellowhead (M. sativa subsp. falcata), tap root type (TR), cv. Equinox (ssp. sativa) and creeping root type (CR), cv. Spredor 4 alfalfa (ssp. sativa), at Melfort, SK, Canada. The five harvest treatments were two 1‐cut systems (early July or late July) and three 2‐cut systems (early July + early or late September, late July + late September). Total forage yield was greater in TR and CR alfalfa than RR alfalfa; however, RR alfalfa had higher total forage yield under dry growing conditions versus CR alfalfa. The three alfalfa cultivars had a similar response to 2‐cut harvest managements. The first cut yield was affected by the timing of the second cut of the previous year with the early September harvest reducing yield more than the late September. Three alfalfa cultivars had similar crude protein (CP), total digestible nutrient (TDN), and acid detergent fiber (ADF) concentrations. There was a significant nutrient yield benefit of TR and CR alfalfa under a 2‐cut system over the RR alfalfa. Although the prairie climate is warming, the findings suggest that a fall rest period until late September is recommended regardless of alfalfa types to maintain high hay yield over multiple years. Core Ideas: Early September harvest in a 2‐cut treatment reduced the July harvest yield in the subsequent year more than the late September harvest.The first killing frost was not an effective indicator for determining onset of the critical rest period.The timing of the first harvest influenced yield of the second cut more than the timing of the second harvest in the fall.M. sativa had significant total nutrient yield advantage over M. falcata under a 2‐cut system.M. falcata produced similar or greater forage yield under dry conditions than M. sativa. [ABSTRACT FROM AUTHOR]

Copyright of Agronomy Journal is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Oat (Avena sativa L.) is the main species used as a companion crop when establishing perennial forages in eastern Canada, and, although other annual species are used, they have not been systematically evaluated. A field study was conducted across five environments to contrast the use of six annual species (berseem clover, Trifolium alexandrinum L.; forage peas, Pisum sativum L.; annual ryegrass, Lolium multiflorum Lamarck; oat; Japanese millet, Echinochloa esculenta [A. Braun] H. Scholz; sudangrass, Sorghum × drummondii [Nees ex. Steud.] Millsp. & Chase) as companion crops for the establishment of alfalfa (Medicago sativa L.)‐timothy (Phleum pratense L.) mixtures. The control treatment consisted of the perennial species seeded without companion crop. Treatments were seeded at three dates and evaluated during the seeding and post‐seeding years. The performance of the six companion crops evaluated herein varied depending on the seeding date and the environment. For a mid‐May to early June seeding total seeding year forage mass was greatest with use of oat, Japanese millet, or sudangrass as companion crops; for a mid‐June to late June seeding with Japanese millet or sudangrass; and for a late July to early August seeding with oat or Japanese millet. These species, however, reduced in some environments seeding year alfalfa or timothy mass compared to a control seeded without a companion crop. Such reduction was also observed in some environments in the first post‐seeding year. Companion crop choice to establish alfalfa–timothy mixtures needs to take into consideration seeding date and forage needs on the short term versus the long term. Core Ideas: Oat is the main companion crop used to establish perennial forages, others can be used but information is limited.Use of oat, Japanese millet, or sudangrass as companion crop produce the greatest seeding year total forage mass.Most productive companion crop species resulted in 19%–31% reduction in first post‐seeding year forage mass.Use of berseem clover, annual ryegrass, and peas minimally impacted seeding and post‐seeding year forage mass.Selection of companion crops must consider seeding date and short‐ and long‐term forage needs. [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa L., AL)‐based forage mixtures are a major constituent of ruminant rations, and optimizing their energy‐to‐protein ratio has been identified as a way to improve N use efficiency. This study aimed to determine whether the energy‐to‐protein ratio could be improved by adding red clover (Trifolium pratense L., RC) or birdsfoot trefoil (Lotus corniculatus L., BT) at different seeding proportions, and/or one grass species [timothy, Phleum pratense L., or tall fescue, Schedonorus arundinaceus (Schreb.) Dumort] to AL. Annual forage yield, species proportion in botanical composition, and nutritive value of forage were measured at three sites in Canada for 2 post‐seeding years. The addition of RC or BT did not affect the annual forage yield but it increased the concentration of forage nonfiber carbohydrates (NFCs), particularly of soluble sugars, and decreased concentrations of crude protein (CP), nonprotein nitrogen (NPN), and rapidly degradable protein (PB1) of AL‐based mixtures. The addition of one percentage unit of RC or BT to forage botanical composition improved the NFC/CP ratio by 0.005, and the NFC/(NPN + PB1) ratio by 0.024. The addition of either grass species to AL mixtures also increased the two ratios, but it was related to a CP decrease with no increase in NFC concentrations. Adding RC or BT to AL‐based mixtures is therefore a valuable strategy to increase the forage energy to protein ratio. Core Ideas: Adding red clover to alfalfa‐based mixtures reduced the protein degradability more than birdsfoot trefoil.Adding red clover or birdsfoot trefoil to alfalfa‐based mixtures improved the energy‐to‐protein ratio.Adding grass to alfalfa‐based mixtures improved the energy‐to‐protein ratio by decreasing the protein concentration. [ABSTRACT FROM AUTHOR]

Genomic information on alfalfa adaptation to long-term grazing is useful for alfalfa genetic improvement. In this study, 14 alfalfa populations were collected from long-term grazing sites (> 25 years) across four soil zones in western Canada. Alfalfa cultivars released between 1926 and 1980 were used to compare degree of genetic variation of the 14 populations. Six agro-morphological and three nutritive value traits were evaluated from 2018 to 2020. The genotyping-by-sequencing (GBS) data of the alfalfa populations and environmental data were used for genotype-environment association (GEA). Both STRUCTURE and UPGMA based on 19,853 SNPs showed that the 14 alfalfa populations from long-term grazing sites had varying levels of parentages from alfalfa sub-species Medicago sativa and M. falcata. The linear regression of STRUCTURE membership probability on phenotypic data indicated genetic variations of forage dry matter yield, spring vigor and plant height were low, but genetic variations of regrowth, fall plant height, days to flower and crude protein were still high for the 14 alfalfa populations from long-term grazing sites. The GEA identified 31 SNPs associated with 13 candidate genes that were mainly associated with six environmental factors of. Candidate genes underlying environmental factors were associated with a variety of proteins, which were involved in plant responses to abiotic stresses, i.e., drought, cold and salinity-alkali stresses. [ABSTRACT FROM AUTHOR]

A three-year (2018–2020) study was conducted in Lanigan (Thin Black soil zone) and Saskatoon (Dark Brown soil zone), SK Canada to compare low-lignin alfalfa (Medicago sativa) cv. Hi-Gest® 360 (HiGest) with alfalfa- cv. AC Grazeland (Grazeland) in monoculture and binary mixtures with hybrid bromegrass (HBG; cv. AC Success) for forage yield, nutrient profile, and establishment costs. Field plots were seeded in August 2017. Stands were harvested at three maturity stages of alfalfa (1 = 10% bloom; 2 = 40% bloom; and 3 = 100% bloom). Compared to Grazeland, HiGest alfalfa yielded 25% less in Saskatoon in monoculture, but no difference was found in Lanigan. Averaged across two sites, HiGest had 8.6% less acid detergent lignin (6.51 vs. 5.95%) and 10.3% greater in vitro neutral detergent fiber digestibility (42.7 vs. 38.7% of neutral detergent fiber). In the binary mixtures, however, differences in yield and quality between the two alfalfas were negligible. The stand establishment costs averaged 300 Canadian dollar (CAD) ha−1, 205 CAD ha−1, 260 CAD ha−1, and 303 CAD ha−1 for HiGest, Grazeland, Grazeland-HBG, and HiGest-HBG, respectively. Hi-Gest® 360 alfalfa could provide higher digestible nutrients when it was used as a monoculture and could maintain quality better into later maturing stages. However, the higher seed price, and no actual advantage in mixtures may delay its adoption. [ABSTRACT FROM AUTHOR]

Fall dormancy is a vital component of alfalfa (Medicago sativa L.) yield in northern climates, but selection for the trait is often done at the expense of winter survival. We performed one cycle of selection to reduce fall dormancy in two winter hardy cultivars (Yellowhead and Peace) using a new indoor screening method. We compared the reduced dormancy populations with their respective initial cultivars for fall dormancy, yield, and winter survival at four sites across Canada. During the establishment and the first production years, plants of the reduced dormancy populations were generally taller in the fall than their respective cultivar, which resulted in a one unit increase of their fall dormancy class. Under field conditions, plants of the reduced dormancy populations had a similar winter survival than those of the initial cultivars. Under simulated winter conditions, freezing tolerance was not affected by selection for reduced dormancy in Peace, whereas a decrease from −24.0 to −21.5 °C was observed in Yellowhead. However, in this cultivar, we noted a 37% yield increase under field conditions and a 40% more vigorous regrowth under simulated winter conditions in the reduced dormancy population. These results showed that the indoor selection method effectively reduced fall dormancy and that indirect responses for yield and winter survival were dependent on the genetic background used as selection material. This selection method could therefore be promising to develop alfalfa cultivars adapted to northern latitudes with high winter hardiness and improved late season yield. Core Ideas: A new indoor method of selection to reduce fall dormancy is efficient in different genetic backgrounds.Fall growth can be manipulated by selection without impairing winter survival to some extent.Indirect responses of the selection on yield depends on the genetic material used. [ABSTRACT FROM AUTHOR]

The effect of synergies between saline-tolerant grass and legume species grown in saline soil, on yield, quality, composition, persistence, and weed suppression was studied in 2019–2021 in a moderately saline soil located in the dark brown soil zone near Saskatoon, Saskatchewan, Canada. 'Halo' alfalfa (ALF), a salt-tolerant cultivar of alfalfa, was seeded in binary mixtures with 'Revenue' slender wheatgrass (ALF-SWG), 'Garrison' creeping meadow foxtail (ALF-CMF), and 'Radisson' smooth bromegrass (ALF-SBG). A complex mixture (quaternary) with all three grasses was also included. Four replicated treatments (n = 4) were randomly allocated to 6.2 × 1.2 m plots in spring 2019. The binary mixtures had similar or slightly better stand establishment compared to the quaternary mixture over the two years (83.3 vs. 76.9%), the quaternary stand showed greater (p = 0.01) establishment in Yr 2 than in Yr 1 (85 vs. 68.8%). There was high weed infestation in all the stands, but ALF-SWG had less weed infestation (23.8 vs. 44.1%) than ALF-CMF, especially in Yr 2 (p = 0.05). There were no significant differences among mixtures in yield, nutritional composition, and nutrient uptake. The ALF-CMF and ALF-SWG binary mixtures had 9 to 23% greater mean total DMY than the other mixtures in the moderately saline soil. The cost of establishing forage mixtures on unproductive saline land can be up to 89% recovered after only two years. The results suggested that binary mixtures of 'Halo' alfalfa with 'Revenue' slender wheatgrass or 'Garrison' creeping meadow foxtail could be reasonable alternatives for adequate forage production and quality, high N-use efficiency, and ultimately livestock gain per hectare, as well as for controlling soil salinity and improving soil fertility in this saline area in the dark brown soil zone. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Alfalfa has a lower fiber digestibility and a greater concentration of degradable protein than grasses. Dairy cows could benefit from an increased digestibility of alfalfa fibers, or from a better match between nitrogen and energy supplies in the rumen. Alfalfa cultivars with improved fiber digestibility represent an opportunity to increase milk production, but no independent studies have tested these cultivars under the agroclimatic conditions of Canada. Moreover, decreasing metabolizable protein (MP) supply could increase N use efficiency while decreasing environmental impact, but it is often associated with a decrease in milk protein yield, possibly caused by a reduced supply of essential AA. This study evaluated the performance of dairy cows fed diets based on a regular or a reduced-lignin alfalfa cultivar and measured the effect of energy levels at low MP supply when digestible His (dHis), Lys (dLys), and Met (dMet) requirements were met. Eight Holstein cows were used in a double 4 × 4 Latin square design, each square representing an alfalfa cultivar. Within each square, 4 diets were tested: the control diet was formulated for an adequate supply of MP and energy (AMP_AE), whereas the 3 other diets were formulated to be deficient in MP (DMP; formulated to meet 90% of the MP requirement) with deficient (94% of requirement: DMP_DE), adequate (99% of requirement: DMP_AE), or excess energy supply (104% of requirement; DMP_EE). Alfalfa cultivars had no significant effect on all measured parameters. As compared with cows receiving AMP_AE, the dry matter intake of cows fed DMP_AE and DMP_EE was not significantly different but decreased for cows fed DMP_DE. The AMP_AE diet provided 103% of MP and 108% of NE L requirements whereas DMP_DE, DMP_AE, and DMP_EE diets provided 84, 87, and 87% of MP and 94, 101, and 107% of NE L requirements, respectively. In contrast to design, feeding DMP_EE resulted in a similar energy supply compared with AMP_AE, although MP supply has been effectively reduced. This resulted in a maintained milk and milk component yields and improved the efficiency of utilization of N, MP, and essential AA. The DMP diets decreased total N excretion, whereas DMP_AE and DMP_EE diets also decreased milk urea-N concentration. Reducing MP supply without negative effects on dairy cow performance is possible when energy, dHis, dLys, and dMet requirements are met. This could reduce N excretion and decrease the environmental impact of milk production. [ABSTRACT FROM AUTHOR]

Timothy (Phleum pratense L.) is expected to be more affected by climate change than other forage grasses. Therefore, alternatives to timothy, such as tall fescue [Schedonorus arundinaceus (Shreb.) Dumort.], meadow fescue [S. pratensis (Huds.) P. Beauv.], or meadow bromegrass (Bromus biebersteinii Roem. & Schult.) should be explored. Our objective was to simulate and compare the yield and nutritive value of four alfalfa (Medicago sativa L.)–grass mixtures and annual crops grown on two virtual dairy farms representative of eastern Canada under future climate conditions. The Integrated Farm System Model (IFSM) was used for these projections under the reference (1971–2000), near future (2020–2049), and distant future (2050–2079) climates for two climatically contrasting agricultural areas in eastern Canada (eastern Quebec; southwestern Quebec). In both future periods, annual forage dry matter (DM) yields of the four alfalfa–grass mixtures are projected to increase because of additional harvests, with greater DM yield increases projected in the colder area than in the warmer area. In both areas, the highest yield increase is projected for alfalfa–tall fescue mixture and the lowest for alfalfa–timothy mixture. The nutritive value of all mixtures should increase due to a greater proportion of alfalfa. In both areas, yields of silage and grain corn (Zea mays L.), and soybean [Glycine max (L.) Merr.] are projected to increase, but not those of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). Tall fescue, meadow bromegrass, and meadow fescue are adequate alternatives to timothy grown in association with alfalfa under future climate conditions. Core Ideas: Forage yields of alfalfa–grass mixtures are projected to increase due to additional harvests.Mixture with tall fescue is projected to increase the most and timothy the least.Tall fescue, meadow fescue, and meadow bromegrass are valuable alternatives to timothy.Nutritive value is projected to increase due to more alfalfa in the mixture.Corn and soybean grain yields are projected to increase but not those of wheat and barley. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Alfalfa (Medicago sativa L.) is one of the most important forage crops in the world. The objectives of this study were to assess alfalfa yield improvement in the Canadian prairies, and determine critical climatic factors influencing alfalfa yield in different soil zones. Forage yield data of alfalfa cultivars tested from 1997 to 2011 in the Western Forage Variety Testing System were used for the analysis. There was no significant trend of alfalfa yield increase in western Canada except at Saskatoon, SK. Regrowth yield of alfalfa cultivars released from 2000 to 2011, however, showed a significant (p ≤ 0.05) increase under irrigation. Based on structural equation modelling (SEM), at rain‐fed sites, precipitation from April to June was the most important driver for the farm hay yield (1st‐cut). Forage yield of alfalfa, however, was not associated with winter extreme temperatures, or number of days with freeze‐thaw temperatures in April. Alfalfa yields were greatest under a 3‐cut than 1‐ or 2‐cut systems in the first production year, but this difference declined as stands became older. Alfalfa stands that were harvested more frequently were less responsive to growing season rain, but responded more strongly to increased snow cover, which may indicate reduced growth and less winder hardiness. At the irrigated sites, 1st‐cut forage yield increased with accumulated temperatures above 5°C from April to June. Development of alfalfa cultivars with tolerance to early season drought and improved regrowth, without reducing winter hardiness, would be necessary to stabilize alfalfa production under changing climate in the Canadian prairies. [ABSTRACT FROM AUTHOR]

Breeding of perennial legumes and initial seed production have been carried out at the Research Institute of Agriculture in Skriveri for nearly 70 years. Eight red clover varieties, two varieties of alsike clover and two varieties of alfalfa have been developed. The varieties are included in the perennial grass seed mixtures and widely used in formation of highly productive meadows and pasture swards. They are characterized by different longevity, ripening time, productivity level, number of sward cuttings per season. There are both diploid and tetraploid varieties, which are suitable for different forage production ways. These varieties are included in the European Common Catalogue of plant varieties and they are grown and multiplied in seed production fields in European countries and Canada. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Megachile rotundata F. populations are managed to pollinate alfalfa, Medicago sativa L. (Fabaceae), for seed production in western North America. Some progeny produced in summer by overwintered M. rotundata females enter diapause as prepupae to overwinter and become adults the following year. Other offspring avert diapause to undergo adult emergence in summer. The regulatory mechanism(s) of diapause induction or aversion is unknown; the process apparently involves multiple and integrated factors. This 4-yr study sought to determine effects of the exposure of mother bees to short, long, very long, and natural photoperiods on their production of non-diapausing and diapausing progeny. Just-emerged adult bees from both Utah and Canada sources were exposed to different photoperiods for 3 d in incubators and then released into field enclosures placed over blooming alfalfa. Control bees were those exposed to only outdoor conditions. Reproduction was monitored for each female bee, and offspring diapause outcome was recorded. Progeny outcome data were informative for only two of the four study years. Generally, progeny of Utah mothers exposed to long and very long photoperiods were more likely to be non-diapausers compared to progeny of mothers exposed to short and control photoperiods. Short and long (but not very long) photoperiod maternal exposures increased the likelihood of diapause aversion in Canada progeny. Performing multiyear field studies on geographically distinct populations is imperative for revealing environmental challenges and inconsistent bee performance that can impair analyses and interpretation. Future similar studies are needed to more fully evaluate photoperiod effects on diapause. [ABSTRACT FROM AUTHOR]

Alfalfa is the most produced perennial forage crop in Canada. Drought stress is a major form of abiotic stress, affecting its productivity and annual yield. A small RNA, miR156 , plays a major role in drought tolerance by downregulating downstream SPL genes, but its effects at the proteome level are unknown. In this study, the protein level perturbations of miR156 overexpression (A8) and empty vector (EV) control genotypes were compared under drought stress. Using label-free quantification, 3000 protein groups were identified, of which 68 were upregulated in A8 and 84 were downregulated relative to EV under control conditions. Conversely, under drought stress, 610 proteins were upregulated and only 52 proteins were downregulated in A8 relative to EV. Functional analysis using PlantRegMap showed that the enriched proteins are likely involved in biological and molecular processes including antioxidant response, response to stress, signal transduction and biosynthesis of secondary metabolites. These proteins/pathways might be involved in the enhancement of drought stress tolerance mediated by miR156. Protein groups related to signaling, such as MAP kinase, calcium-dependent protein kinase, protein phosphatase 2 C, and transcriptional regulators including bZIP and zinc finger proteins were found to be differentially expressed when a search was conducted against a drought stress gene database. The proteomic dataset was validated by immunoblotting of selected proteins. The results of this study provide a better understanding and insight into the role of miR156 in drought stress tolerance in alfalfa at the proteomic level. • Overexpression of the small RNA miRNA156 protects alfalfa against drought stress. • The impact of miRNA156 on the proteome was studied by label-free quantification. • Gene ontology categories related to stress responses were enriched. • Proteins encoded by known drought stress genes were differentially expressed. • Results provide insight into the role of miR156 in drought stress tolerance. [ABSTRACT FROM AUTHOR]

The ‘Day of Action to Stop GM Alfalfa’ was a Canada-wide protest that took place in 38 different cities on April 9th, 2013. Organized by a coalition of farmers and activists, these rallies protested potentially adverse impacts to markets, the environment, and society, and were picked up by news media outlets across the country. Despite the protestors’ focus on a range of concerns, news outlets tended to cover particular issues, such as economic and market impacts while broader social, political, and environmental issues received only peripheral attention. This article contributes to literature on GMO protests and media analyses by offering an explanation for the news media’s focus on economic over other concerns, and the power relations embedded in this focus. Based on a discourse analysis of 88 news reports on GM alfalfa published over a four year period, this article identifies under-acknowledged power relations that influence (largely inadvertently) the direction of reporting. Specifically, GM alfalfa news coverage is influenced in two key ways: (1) news values and media culture shape the report writing and editing process, privileging ‘newsworthy’ topics while side-lining others; and (2) neoliberal normative assumptions act as underlying hegemonic discourses that re-embed dominant knowledges—common sense values and assumptions regarding market mechanisms and privatization go unnoticed, or at least uncriticized. [ABSTRACT FROM AUTHOR]

Alfalfa semi-hybrids (alias free-hybrids or chance-hybrids) of genetically-distant populations may display heterosis, but their actual value is substantially unknown. Higher biomass yield may also derive from heterogeneity in cultivar mixtures. This study aimed to compare three two-way and one three-way semi-hybrids and three two-way physical mixtures issued from putative heterotic populations selected from elite Italian germplasm, Egyptian germplasm and a semi-erect pool from Eastern Europe, Canada and Spanish Mielga, their source populations, and a reference synthetic variety selected from the same pool as the Italian population. We assessed three-year dry-matter biomass yield, final persistence, adaptability and yield stability across eight densely-planted managed environments obtained by the factorial combination of two summer water amounts by two soil types by pure stand (PS) or mixed stand (MS) with forage grasses. Heterogeneity increased yield by 17.0% on average while affecting persistence inconsistently. The advantage over mid-parent value averaged 35.1% for yield and 16.3% for persistence of two-way semi-hybrids, while being 35.6% for yield and 21.1% for persistence of the three-way semi-hybrid. The top-yielding semi-hybrid, issued from Italian and Egyptian material, out-yielded both parent populations, and exhibited 7.4% higher mean yield and greater competitive ability than the reference synthetic variety. PS or MS condition affected plant material × environment interaction for yield or persistence more than summer water availability or soil type, but interaction patterns were mainly quantitative with increasing variation in MS. No manifest plant material variation emerged for yield stability. Based on our results, a semi-hybrid variety type can be valuable for alfalfa. • Semi-hybrids of geographically-contrasting, selected pools exhibited large heterosis. • Heterogeneity effects due to physical mixture were sizable but smaller than heterotic effects. • Semi-hybrid material outperformed the reference synthetic variety bred from local germplasm. • Semi-hybrid breeding depends crucially on prior selection of exotic germplasm for local adaptation. [ABSTRACT FROM AUTHOR]

Aims: We carried out a paired-site study (Melanic Brunisol) to assess the impact on soil carbon stocks of land-use change following establishment and multiple rotations of willows (Salix miyabeana SX67) in short-rotation coppice (SRWC). Methods: Total soil organic carbon (TSOC), hot-water extractable carbon (HWC) and amino sugars (AS) were used as main parameters of soil carbon dynamic. Results: We found that the establishment event and 2 years of growth under SRWC did not result in any change in the TSOC pool or in the HWC pool. However, we found an increase in AS at and near the soil surface (0-20 cm) of the establishing willow plantations. We related this to the effect of the green manure applied before planting. After multiple rotations of SRWC, we found a redistribution of TSOC in the vertical profile (0-40 cm) but no TSOC difference compared to previous land-use (abandoned alfalfa crop). In the subsoil (20-40 cm), we found indications that the more labile soil organic carbon (SOC) pools were depleted (HWC and muramic acid). Conclusions: Willow plantations on Melanic Brunisol in southern Quebec (Canada) represent, over the long-term, a soil carbon sink when replacing a short-term no-till crop rotation. However, the conversion from abandoned alfalfa fields into SRWC does not apparently enhance soil carbon potential sequestration. [ABSTRACT FROM AUTHOR]

Background: Feral populations of cultivated crops can pose challenges to novel trait confinement within agricultural landscapes. Simulation models can be helpful in investigating the underlying dynamics of feral populations and determining suitable management options. Methodology/Principal Findings: We developed a stage-structured matrix population model for roadside feral alfalfa populations occurring in southern Manitoba, Canada. The model accounted for the existence of density-dependence and recruitment subsidy in feral populations. We used the model to investigate the long-term dynamics of feral alfalfa populations, and to evaluate the effectiveness of simulated management strategies such as herbicide application and mowing in controlling feral alfalfa. Results suggest that alfalfa populations occurring in roadside habitats can be persistent and less likely to go extinct under current roadverge management scenarios. Management attempts focused on controlling adult plants alone can be counterproductive due to the presence of density-dependent effects. Targeted herbicide application, which can achieve complete control of seedlings, rosettes and established plants, will be an effective strategy, but the seedbank population may contribute to new recruits. In regions where roadside mowing is regularly practiced, devising a timely mowing strategy (early- to mid-August for southern Manitoba), one that can totally prevent seed production, will be a feasible option for managing feral alfalfa populations. Conclusions/Significance: Feral alfalfa populations can be persistent in roadside habitats. Timely mowing or regular targeted herbicide application will be effective in managing feral alfalfa populations and limit feral-population-mediated gene flow in alfalfa. However, in the context of novel trait confinement, the extent to which feral alfalfa populations need to be managed will be dictated by the tolerance levels established by specific production systems for specific traits. The modelling framework outlined in this paper could be applied to other perennial herbaceous plants with similar life-history characteristics. [ABSTRACT FROM AUTHOR]

The article provides information on Bridgeview alfalfa. The Agriculture and Agri-Food Canada Research Centrre in Lethbridge, Alberta developed the salt tolerant cultivar for enhanced seeding strength and high yield. The alfalfa demonstrated higher emergence, biomass production, and survival. The cultivar's pedigree and breeding methods, performance, maintenance, varietal characteristics, and distribution are discussed.

Abstract: Grass reference evapotranspiration (ETo) is an important agrometeorological parameter for climatological and hydrological studies, as well as for irrigation planning and management. There are several methods to estimate ETo, but their performance in different environments is diverse, since all of them have some empirical background. The FAO Penman–Monteith (FAO PM) method has been considered as a universal standard to estimate ETo for more than a decade. This method considers many parameters related to the evapotranspiration process; net radiation (Rn), air temperature (T), vapor pressure deficit (Δe), and wind speed (U); and has presented very good results when compared to data from lysimeters populated with short grass or alfalfa. In some conditions, the use of the FAO PM method is restricted by the lack of input variables. In these cases, when data are missing, the option is to calculate ETo by the FAO PM method using estimated input variables, as recommended by FAO Irrigation and Drainage Paper 56. Based on that, the objective of this study was to evaluate the performance of the FAO PM method to estimate ETo when Rn, Δe, and U data are missing, in Southern Ontario, Canada. Other alternative methods were also tested for the region: Priestley–Taylor, Hargreaves, and Thornthwaite. Data from 12 locations across Southern Ontario, Canada, were used to compare ETo estimated by the FAO PM method with a complete data set and with missing data. The alternative ETo equations were also tested and calibrated for each location. When relative humidity (RH) and U data were missing, the FAO PM method was still a very good option for estimating ETo for Southern Ontario, with RMSE smaller than 0.53mmday−1. For these cases, U data were replaced by the normal values for the region and Δe was estimated from temperature data. The Priestley–Taylor method was also a good option for estimating ETo when U and Δe data were missing, mainly when calibrated locally (RMSE =0.40mmday−1). When Rn was missing, the FAO PM method was not good enough for estimating ETo, with RMSE increasing to 0.79mmday−1. When only T data were available, adjusted Hargreaves and modified Thornthwaite methods were better options to estimate ETo than the FAO PM method, since RMSEs from these methods, respectively 0.79 and 0.83mmday−1, were significantly smaller than that obtained by FAO PM (RMSE =1.12mmday−1). [Copyright &y& Elsevier]

The alfalfa leafcutting bee, Megachile rotundata F. (Hymenoptera: Megachilidae), is widely used as a pollinator for production of alfalfa, Medicago sativa L., seed, and populations of these bees can be maintained by alfalfa seed growers or can be purchased from mostly Canadian bee providers. M. rotundata raised in Canada have higher survival rates during the incubation that occurs after winter storage than do bees produced in the northwestern United States, but no reason has been found for this difference. We investigated whether storing immature M. rotundata for various time periods at a warm temperature (16°C) before winter or allowing them to remain unmanaged at ambient temperatures affects physiological aspects of prepupae during the winter as well as the survival and longevity of adult bees after spring or summer incubation. Our results show that the timing of the onset of winter storage and incubation does affect prepupal weights, prepupal lipid and water contents, adult emergence, and adult female longevity. Winter storage of prepupae in November or December with a late June incubation resulted in heavier adults that emerged more readily than bees incubated in late May, However, adult females incubated in May thrived longer than June-incubated bees if fed a honey-water diet. Thus, some prewinter management regimes for M. rotundata commercial stocks may be more effective than others for achieving optimal adult emergence synchrony, as well as adult survival and longevity for pollination of a summer crop. [ABSTRACT FROM AUTHOR]

Freezing tolerance is a determinant factor of persistence of alfalfa (Medicago sativa L.) grown in northern climates. Selection for winter hardiness in field nurseries is difficult because of the unpredictability of the occurrence of test winters allowing the identification of hardy genotypes. A method of selection entirely performed indoor in growth chambers and walk-in freezers has been applied for the identification of genotypes with superior freezing tolerance. Using that approach, cultivars recommended for growth in eastern Canada have been submitted to cycles of recurrent selection to generate populations potentially more tolerant to freezing (TF). Subsequent determination of the freezing tolerance of populations recurrently selected using plants acclimated to natural hardening conditions in an unheated greenhouse revealed a progressive increase in response to this selection approach. Field assessment of TF populations also showed better survival and forage yield than originat cultivars at sites that experienced severe winter conditions. At stressed sites, a significant proportion of the variance in the yields of the populations was explained by freezing tolerance potential. Our results show that major increases in freezing tolerance (between 3 and 5°C) of alfalfa and better survival to severe winter conditions in the field can be achieved by screening for freezing tolerance under indoor growing conditions and intercrossing the selected plants. [ABSTRACT FROM AUTHOR]

Nitrogen (N) budgets can be used to quantify the flows of N in agroecosystems and to account for differences in losses and retention of N. The objective of our study was to develop 24-year N budgets for three diverse cropping systems on a boreal soil at Breton, Alberta, Canada: AER – an agroecological 8-year rotation, with N inputs from legumes [fababean (Vicia faba L.), red clover (Trifolium pratense L.), alfalfa (Medicago sativa L.)] and manure; CF – a continuous perennial grass–legume forage system, with N inputs from fertilizer (18kgNha−1 yr−1) and white clover (Trifolium repens L.); and CG – a continuous annual grain system, with N fertilizer (90kgNha−1 yr−1). We were able to compile detailed N budgets, demonstrate accumulation of soil N, and attribute differences in N flow and permanence to treatment effects. For AER and CG, net inputs almost exactly matched gains in soil N. The AER system had the highest N flow and the largest net N accumulation. Soil total N mass to 30cm depth increased in all systems during 1980–2005, but increases were smaller in CG (0.59MgNha−1) than in AER (1.90MgNha−1) and CF (1.63MgNha−1), showing the effect of legumes, perennial species, and manure in the latter systems. The proportion of total N inputs retained as soil N with organic N inputs in AER (44%) was about twice that with synthetic N fertilizer in CG (23%). The CF system had the lowest productivity and the least N loss to the environment (4kgNha−1 yr−1, compared to 28 for AER and 24 for CG). The proportion of N inputs lost to the environment was 16% for AER and 24% for CG. In CF, gains of soil N exceeded apparent net N inputs, perhaps because we under-estimated N inputs from clover. Estimate of legume N input was one of the larger sources of uncertainty. The study affirmed the value of N budgets in evaluating agroecosystem performance, and identified AER and CF as productive and sustainable systems due to their minimal reliance on external N inputs and small N losses to the environment. [Copyright &y& Elsevier]

This study describes the time-course of the accumulation of total soluble proteins (TSPs) and vegetative storage proteins (VSPs) and of the transcripts of cold-inducible (CI) and VSP-encoding genes in taproots of two alfalfa cultivars (AC Caribou and Europe) during their acclimation to natural autumn hardening and overwintering conditions in eastern Canada. The impact of a defoliation in September on these winter hardening-related changes was also assessed. Both concentrations and pools of VSPs increased significantly between early September and mid-October and remained unchanged thereafter, concomitantly with the disappearance of VSP-encoding transcripts. Other soluble protein constituents continued to increase later in the autumn and early winter and accounted for nearly 60% of taproot TSP pools in winter. As a result, VSP abundance relative to TSPs decreased markedly during the winter. The increase in the levels of CI transcripts was induced by lowering temperatures, and distinct patterns suggest differences in the regulation of their accumulation. RNA analyses revealed that the accumulation of VSP transcripts during the autumn precedes the accumulation of CI transcripts. Autumn defoliation interrupted the accumulation of both TSPs and VSPs during autumn hardening and repressed the transcript levels of two CI genes differentially between cultivars. The well-documented impact of autumn defoliation on the vigour of spring regrowth and long-term persistence of alfalfa could be related to its negative impact on the accumulation of VSPs and TSPs and on the expression of genes encoding CI proteins potentially involved in cold tolerance and pathogen resistance. [ABSTRACT FROM PUBLISHER]

Verticillium wilt of alfalfa, caused by Verticillium albo-atrum, may reduce forage yields by up to 50% in alfalfa-producing areas of the northern United States and Canada. It has been suggested that cultivars require at least 60% resistant plants to afford maximum protection against disease. Our objective was to calculate heritability estimates of resistance to Verticillium wilt in alfalfa. Estimates were generated for two alfalfa populations developed from the cvs. Affinity + Z and Depend + EV. Heritability on a half-sib progeny means basis was calculated based on data from greenhouse pathogenicity tests. Estimates based on repeated experiments conducted for single years (2004 and 2005) were high for both populations, ranging from 0.86 to 0.92. The heritability estimate based on data collected over 2 years was 0.26 for Affinity + Z and 0.66 for Depend + EV. Disease was more severe in 2005 than in 2004. However, the Spearman rank correlation between mean disease severity index values for half-sib families over 2 years was positive and significant for both populations. Results of pathogenicity tests suggested that neither cultivar had resistance levels approaching 60%. The heritability estimates suggest that resistance levels in both Affinity + Z and Depend + EV could be improved further through selection. [ABSTRACT FROM AUTHOR]

Six empirical functions were compared for describing the product yields of agricultural crops grown while subject to increasing levels of root-zone salinity. The four nonlinear functions fit the test data from a spring wheat (Triticum aestivum L., cv. Biggar) experiment conducted in Canada's Salt Tolerance Testing Facility closer than the two linear functions. Although each of the four nonlinear declining functions could reasonably describe the data, the modified compound-discount equation recorded the lowest root mean square error and the highest R² value. Additional response data using the nonlinear discount function obtained from 33 separate trials averaged 11% closer in statistical fit and 45% lower in statistical error than the best linear function. The discount function (Yr = 1/(1 + [(C/C50)exp(sC50)]) follows a sigmoidal form and relates relative yield (Yr) to a measure of root-zone salinity (C) such as the solute concentration with an electrical conductivity of an equivalent saturated soil paste extract (ECe). This function features two parameters, the salinity level producing 50% of the nonsalinc crop yield (C50) and the absolute value of the general decline in relative yield with salinity at and near C50, the steepness constant (a). These parameters combine to form a single- value, salinity-tolerance index (ST-Index) consisting of the 50% reduction in crop yield (C50) plus the tendency to maintain some product yield as the crop is subjected to increasing salinity levels approaching C50, i.e., ST-Index = C50 + s(C50). The ST-Index for the Biggar wheat registered 6.44. Approximations for C50 and s can be derived from the threshold salinity (Ct) and declining slope (b) parameters of the threshold-slope linear response function [Yt = 1 - b(C - Ct]. Procedures for converting Ct to C50 and b to a offer linkages between these linear and nonlinear response function parameters, and are further explored in this paper's companion. The resulting ST-Index-values equal 6.56, 9.43, and 5.67 for sample field (corn, Zea mays L.), forage (alfalfa, Medicago sativa L. and falcata L.), and vegetable (radish, Raphanus sativus L.) crops, respectively. [ABSTRACT FROM AUTHOR]

Discusses the evidence for the heritability of resistance to brown root rot (BRR) of alfalfa, caused by Phoma sclerotioides, a low-temperature pathogen. BRR in legume roots in several Canadian provinces; Heritability of BRR resistance; Disease severity.

A grazing experiment was conducted in Brandon, Manitoba, Canada. The objectives were to examine the effects of including alfalfa and fertilizer management on N2 fixation by alfalfa and plant N dynamics, and to compare N budgets in the four contrasting pasture systems and external energy inputs between fertilizer-N-based and legume-based pasture systems. Estimates of annual amounts of N2 fixed, based on shoot herbage production in grazed mixed alfalfa/grass pastures, ranged from 40 to 118 kg N ha-1 y-1. The amounts would be in the range of 52–153 kg N ha-1 y-1, if the amounts of fixed N stored in the roots, were included. Compared to grass-only pastures, total amounts of N2 fixed in the mixed pastures should be sufficient to improve total external N inputs, replace N fertilizer and sustain plant protein for grazing. The reliance of alfalfa (Medicago sativa L.) on N2 fixation for growth was high (70–95%), and %N derived from the atmosphere by alfalfa (%Ndfa) was not affected by P fertilizer management. Thus, the amounts of N2 fixed were predominantly regulated by alfalfa dry matter productivity. The data also indicated that alfalfa fixed 27 kg N t-1 dry matter produced. In mixed alfalfa/grass pastures, high soil mineral N uptake by companion grasses, was essential to effectively utilize N that was fixed by alfalfa and returned to soils through the decomposition of alfalfa litter and roots. Compared to grass-only pastures with or without N fertilizer, alfalfa-based pastures could supply sufficient plant protein for grazing animals through N2 fixation, and at same time, sustain animal productivity with only 28% of the external energy input of the grass-only pasture with N fertilizer. [Copyright &y& Elsevier]

There has been a great deal of uncertainty in the reported alfalfa and pasture yields in the agricultural database as these commodities are typically used internally on farms and are not sold in the same way as other crops such as wheat, canola or corn. However, yields from alfalfa and pasture crops are important inputs (biological fixation) and outputs (feed) that can impact the estimates of agri-environmental indicators as the land area in Canada under these crops is very large. One of the indicators which uses this data is the residual soil nitrogen (RSN) which is the amount of inorganic N remaining in soils after harvest. High RSN levels can lead to impaired water quality (e.g., eutrophication) and global warming (N 2 O). Therefore, it is critical to obtain accurate alfalfa and pasture yield estimates. In previous versions of the Canadian Agricultural Nitrogen Budget Model (CANB), only provincial average yield values were used for alfalfa or pasture yields across all of the soils and landscapes. Soils, climates, and crop yields do vary within provinces, and a more accurate estimate of these yields over time and space is required. The objective of this study was to collect recent published yield data and use the Environmental Policy Integrated Climate (EPIC) to estimate yields for the 2780 soil landscapes of Canada (SLC) polygons. The EPIC model was used to calibrate and evaluate yields at field scale based on a total of 109, 59 and 47 treatments collected for alfalfa, improved and unimproved pasture yields, respectively, from Canadian publications. Due to satisfactory evaluation, we extended simulation to all SLC polygons based on SLC v3.2 soil and weather databases, representative crops as proxies for planting and harvesting date, and historical rates of fertilization. The average simulated alfalfa, improved and unimproved pasture yields were 5.00, 3.85 and 1.22 Mg ha−1, respectively over the period from 1981 to 2019. Generally, the EPIC model showed reliable predictions for alfalfa and pasture yields under variable weather, soil, and management practices. Therefore, it enabled us to provide improved estimates across soil landscapes polygons in Canada and thereby improve our agri-environmental indicator models. [Display omitted] • Built a yield dataset of alfalfa, and pasture from Canadian publications • Calibrate and evaluate EPIC model based on field research treatments • Simulate alfalfa and pasture yields on 2780 agricultural polygons from 1981 to 2019. • This study fills the yield gaps of alfalfa and pasture for a CANB Reactive N model. [ABSTRACT FROM AUTHOR]

• Uncertainty predicting zero-N maize yield varied between 2.0 to 2.5 Mg ha−1. • Previous crop, irrigation, and soil organic matter were the most relevant predictors. • Spring weather provided key information for refining the yield prediction. Maize (Zea Mays L.) yield responsiveness to nitrogen (N) fertilization depends on the yield under non-limiting N supply as well as on the inherent productivity under zero N fertilizer (Y 0). Understanding the driving factors and developing predictive algorithms for Y 0 will enhance the optimization of N fertilization in maize. Using a random forest algorithm, we analyzed data from 679 maize N fertilization studies (1031 Y 0 observations) conducted between 1999–2019 in the United States and Canada. Predictability of Y 0 was assessed while identifying determinant factors such as soil, crop management, and weather. The inclusion of weather variables as predictors improved the model efficiency (ME) from 51 up to 64 %, and reduced the root mean square error (RMSE) from 2.5 to 2.0 Mg ha−1, 34 to 27 % in relative terms (RRMSE). The most relevant predictors of Y 0 were previous crop, irrigation, and soil organic matter (SOM), while the most influential weather data was linked to the radiation per unit of thermal time (Q quotient) around flowering and spring precipitations. The crop rotation effect resulted in Alfalfa (Medicago sativa L.) as the previous crop with the highest Y 0 level (IQR = 11.5–15.0 Mg ha−1) as compared to annual legumes (IQR = 5.6–10.0 Mg ha−1) and other previous crops (IQR = 3.6–7.8 Mg ha−1). The Q quotient around flowering positively affected Y 0 , while spring precipitations and extreme temperature events during grain filling showed a negative association to Y 0. Overall, these results reinforce the concept that yields are controlled not only by soil N supply but also by factors modifying plant demand and ability to capture N. Lastly, we foresee a promising future for the use of machine learning to address both prediction and interpretation of maize yield to obtain more reliable N guidelines. [ABSTRACT FROM AUTHOR]

• Using estimated temperatures under snow cover is required for the simulation of alfalfa regrowth in eastern Canada with DSSAT. • The simulated values of aboveground biomass across all sites and years in the six experimental datasets were acceptable. • Additional model functions may be required to further improve the simulation of alfalfa regrowth for climate change. • Functions on reduced plant density by freezing and snow insulation are needed for modelling in northern regions. Alfalfa (Medicago sativa L.) is the predominant forage legume species in Canada and is considered a prioritized option for sustainable cropping under climate change. Crop growth models provide an opportunity to explore the potential impacts of climate change on alfalfa and for evaluating potential adaptation options. For this study, six experimental datasets in eastern Canada were used to parameterize the newly adapted CSM-CROPGRO-Perennial Forage Model (CSM-CROGRO-PFM) in simulating alfalfa regrowth and to identify areas for further model improvement needed for climate change assessments in the northern agricultural regions of North America. Estimated air temperatures under snow cover were used successfully to drive the CSM-CROPGRO-PFM model for simulating alfalfa regrowth in eastern Canada. The simulated values of aboveground biomass across all sites and years were acceptable with a root mean square error (RMSE) of 936 kg dry matter (DM) ha−1 and a normalized RMSE of 24%. A sensitivity analysis of the model revealed that with no change in the number of harvests per year, the simulated annual herbage yield (harvestable biomass) declined with increasing temperature, increased with elevated atmospheric CO 2 concentration, and changed little with increased precipitation. However, the increase in the number of harvests made possible by warmer temperatures may increase the simulated annual herbage yield. Although most alfalfa physiological processes were successfully simulated, some additional model functions may be required to further improve the simulation of alfalfa regrowth for climate change studies conducted in Canada. These functions include quantifying plant density decline and its relationship with biomass in post-seeding years, estimating temperatures surrounding alfalfa crowns during the overwintering period, and simulating herbage nutritive attributes. [ABSTRACT FROM AUTHOR]

Abstract: Antimicrobial seed treatments recommended by Canadian guidance for sprouted vegetable production (2,000 ppm of hypochlorite for 15 to 20 min or 6 to 10% hydrogen peroxide for 10 min at room temperature) are not fully compliant with organic production principles. We investigated the effect of a sequential treatment consisting of a 10-min soak at 50°C in water followed by exposure to a 2.0% H2O2 plus 0.1% AcOH sanitizing solution against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica inoculated onto alfalfa and radish seed. The sequential treatment was as effective as the recommended treatments and could reduce populations of all three species by a minimum of 3 log CFU/g using a reduced (1:2) ratio of seed to sanitizing solution and low concentrations of sanitizers approved for use in organic food production. However, the efficacy of all the treatments examined in this work was considerably reduced by storage of the seed for 4 weeks at either 11 or 75% relative humidity prior to treatment and assessment. None of the treatments could eradicate the target pathogens from seed, irrespective of time elapsed since inoculation. The results of this work suggest that the effect of storage should be considered in the assessment of antimicrobial treatments for sprouting vegetable seed., (Published 2020 by the International Association for Food ProtectionCopyright ©, Her Majesty the Queen in Right of Canada as represented by Agriculture and Agri-Food Canada.)