Smooth Bromegrass Research Articles

Evaluation of growth performance, carcass characteristics, and methane and CO2 emissions of growing and finishing cattle raised in extensive or partial-intensive cow-calf production systems.

An experiment was conducted over 2 yr to measure performance and greenhouse gas (GHG) emissions of weaned calves from two cow-calf production systems. Crossbred steers and heifers (n = 270, initial body weight (BW) = 207 kg, SD = 35) were used in a randomized complete block design, with treatments applied to the cow-calf system. Treatments were: 1) a traditional system consisting of April to June calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to September calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). Calves from both production systems were weaned at the same age and grown (diet NEg = 1.05 Mcal kg-1) for approximately 117 d. The calves then transitioned to a high-grain finishing diet (year 1: NEg = 1.32 Mcal kg-1; year 2: NEg = 1.39 Mcal kg-1) and fed to a targeted 1.52 cm backfat. Growth performance in the grower phase resulted in greater (P < 0.01) average daily gain (1.39 vs. 1.22 ± 0.02 kg), greater gain:feed (P < 0.01; 0.157 vs. 0.137 ± 0.003) for ALT calves compared to TRAD calves, However, a lower initial BW (P < 0.01; 185 vs. 229 ± 4.9 kg) resulted in a lower ending BW (P < 0.01; 347 vs. 371 ± 2.9 kg) for ALT calves compared to TRAD calves in spite of improved growth performance. In the finisher phase, ALT calves gained less (1.52 vs. 1.81 ± 0.218 kg; P = 0.02), were less efficient (0.139 vs. 173 ± 0.0151; P = 0.01) but exhibited similar hot carcass weights (HCW) (388 vs. 381 ± 3.8 kg; P = 0.14) compared to TRAD calves. Each pen of calves was put into a large pen-scale chamber that continuously measured carbon dioxide (CO2) and methane (CH4) for 5 d during the grower and finisher phases. The average CH4 and CO2 production per unit of feed intake was used to calculate total GHG emissions over the entire grower and finisher phase. Overall, there were no differences (P ≥ 0.17) between treatments for CH4 per day and per kilogram dry matter intake (DMI). However, ALT calves tended to produce less (P ≤ 0.10) CO2 per day and per kilogram DMI than TRAD calves. Overall, methane emissions were greater in ALT calves (110.7 vs. 92.2 ± 8.3 g CH4 kg-1 HCW; P = 0.04) than TRAD calves. The ALT calves required 27 additional days on feed to market, which resulted in more total CH4 per animal across the entire feeding period (P = 0.02) than TRAD calves. Production systems that reduce days to market to achieve similar HCW may reduce GHG emissions.

Association analysis revealed loci linked to post-drought recovery and traits related to persistence of smooth bromegrass (Bromus inermis).

Association analysis has been proven as a powerful tool for the genetic dissection of complex traits. This study was conducted to identify association of recovery, persistence, and summer dormancy with sequence related amplified polymorphism (SRAP) markers in 36 smooth bromegrass genotypes under two moisture conditions and find stable associations. In this study, a diverse panel of polycross-derived progenies of smooth bromegrass was phenotyped under normal and water deficit regimes for three consecutive years. Under water deficit, dry matter yield of cut 1 was approximately reduced by 36, 39, and 37% during 2013, 2014, and 2015, respectively, compared with the normal regime. For dry matter yield of cut 2, these reductions were approximately 38, 60, and 56% in the same three consecutive years relative to normal regime. Moreover, water deficit decreased the RY and PER of the genotypes by 35 and 28%, respectively. Thirty primer combinations were screened by polymerase chain reaction (PCR). From these, 541 polymorphic bands were developed and subjected to association analysis using the mixed linear model (MLM). Population structure analysis identified five main subpopulations possessing significant genetic differences. Association analysis identified 69 and 46 marker-trait associations under normal and water deficit regimes, respectively. Some of these markers were associated with more than one trait; which can be attributed to pleiotropic effects or tightly linked genes affecting several traits. In normal and water-deficit regimes, these markers could potentially be incorporated into marker-assisted selection and targeted trait introgression for the improvement of drought tolerance of smooth bromegrass.

Carbon footprint of perennial bioenergy crop production receiving various nitrogen fertilization rates

Perennial bioenergy crops can reduce greenhouse gas emissions compared to fossil fuels, but little is known about their C footprints. We evaluated C footprint and C balance of perennial bioenergy crops receiving various N fertilization rates and visually compared them with an annual crop from 2012 to 2014 in the semiarid region of US northern Great Plains. Perennial bioenergy crops were intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth and Dewey, IW), smooth bromegrass (Bromus inermis L., SB), and switchgrass (Panicum virgatum L., SG), and N fertilization rates were 0, 28, 56, and 84 kg N ha−1. The annual crop was spring wheat (Triticum aestivum L., WH). The CO2 flux increased in the summer when air temperature and precipitation were greater. Cumulative annual CO2 flux was greater for SB and SG than IW in 2012–2013 and greater for SB than IW and SG in 2013–2014. Shoot C increased with increased N fertilization rate and was greater for SG than IW and SB at most N fertilization rates in both years. Root and rhizosphere C varied with N fertilization rates and were lower for SG than IW and SB at 0 kg N ha−1, but greater at 84 kg N ha−1. Carbon balance also varied with N fertilization rates, being lower for SG than IW and SB at 0 kg N ha−1, but greater at other N rates. Cumulative CO2 flux was higher, but shoot, root, and rhizosphere C as well as C balance were lower for WH than perennial bioenergy crops. Because of greater total C input but lower CO2 flux, SG with N fertilization can be C positive, retaining more C in plant residue and soil than other perennial bioenergy crops. Spring wheat remained C negative compared to perennial bioenergy crops, losing more C as CO2 flux than total C input.

Cultivation of Legume and Gramineous Grass Mixtures for Use on Hayfields and Pastures of Southern Sakhalin

Nowadays due of the world population growth, the demand for agricultural products is also growing. To obtain good meat and dairy products, high-quality feed for farm animals is necessary. Legume-gramineous perennial grass mixtures are used to improve fodder lands. Our experience included a test of 9 variants of legume-gramineous grass mixtures, where 6 types of grasses were used: red clover, alfalfa (legumes), meadow timothy grass, orchard-grass, smooth brome-grass, meadow fescue (cereals). The experiments were carried out in four repetitions on the lands of hay and pasture use with the use of fertilizers; there were carried out phenological observations, biometric measurements, and determination of the botanical composition. In herbage from hay fields the smooth brome-grass dominated, and in herbage from pastures the orchard-grass dominated. The proportion of non-sown grass species reaches 26.3-32.7 % in three-component grass mixtures with meadow timothy grass. Meadow fescue and meadow timothy in terms of growth rate, reactions to nitrogen application were inferior to the orchard-grass and smooth bromegrass, which led to their oppression and displacement from the herbage. The best density of plant standing per 1 m2 was noted in the orchard-grass and smooth bromegrass, the smallest - in meadow fescue and alfalfa.

Simulating the hydrological impacts of land use conversion from annual crop to perennial forage in the Canadian Prairies using the Cold Regions Hydrological Modelling platform

Abstract. The Red River is one of the largest contributing sources of discharge and nutrients to the world's 10th largest freshwater lake, Lake Winnipeg. Conversion of large areas of annual cropland to perennial forage has been proposed as a strategy to reduce both flooding and nutrient export to Lake Winnipeg. Such reductions could occur either via a reduction in the concentration of nutrients in runoff or through changes in the basin-scale hydrology, resulting in a lower water yield and the concomitant export of nutrients. This study assessed the latter mechanism by using the physically based Cold Regions Hydrological Modelling platform to examine the hydrological impacts of land use conversion from annual crops to perennial forage in a subbasin of the La Salle River basin in Canada. This basin is a typical agricultural subbasin in the Red River Valley, characterised by flat topography, clay soils, and a cold subhumid, continental climate. Long-term simulations (1992–2013) of the major components of water balance were compared between canola and smooth bromegrass, representing a conversion from annual cropping systems to perennial forage. An uncertainty framework was used to represent a range of fall soil saturation status (0 % to 70 %), which governs the infiltration to frozen soil in the subsequent spring. The model simulations indicated that, on average, there was a 36.5 ± 6.6 % (36.5 ± 7.2 mm) reduction in annual cumulative discharge and a 29.9 ± 16.3 % (2.6 ± 1.6 m3 s−1) reduction in annual peak discharge due to forage conversion over the assessed period. These reductions were driven by reduced overland flow 52.9 ± 12.8 % (28.8 ± 10.1 mm), increased peak snowpack (8.1 ± 1.5 %, 7.8 ± 1.6 mm), and enhanced infiltration to frozen soils (66.7 ± 7.7 %, 141.5 ± 15.2 mm). Higher cumulative evapotranspiration (ET) from perennial forage (34.5 ± 0.9 %, 94.1 ± 2.5 mm) was also predicted by the simulations. Overall, daily soil moisture under perennial forage was 18.0 % (57.2 ± 1.2 mm) higher than that of crop simulation, likely due to the higher snow water equivalent (SWE) and enhanced infiltration. However, the impact of forage conversion on daily soil moisture varied interannually. Soil moisture under perennial forage stands could be either higher or lower than that of annual crops, depending on antecedent spring snowmelt infiltration volumes.

ЭФФЕКТИВНОСТЬ ИСПОЛЬЗОВАНИЯ МНОГОЛЕТНИХ ТРАВ В РЕШЕНИИ ПРОБЛЕМЫ БИОЛОГИЗАЦИИ ЗЕМЛЕДЕЛИЯ РЕСПУБЛИКИ КАРЕЛИЯ

One of approaches to biologization of agriculture in Karelia is a widespread use of perennial grasses, which are a source of fodder and perform important ecological functions. We compared yield and protein productivity (tons/hectare) of one- and three-species grass stands including foxtail clover Trifolium rubens, eastern galega Galega orientalis, alfalfa Medicago varia Mart, smooth bromegrass Bromus inermis, and timothy Phleum pratense grown without mineral fertilizers or with N45P60K90 using the two-cut mode of mowing the green mass. Clover (dry weight up to 8.6, crude protein 1.51), as well as alfalfa + clover + timothy (9.4 and 1.32, respectively) featured the highest productivity. The annual spring application of mineral fertilizers caused but an insignificant increase in the yield of clover biomass, which suggests that there is no need for their application. For the biologization of a northern agriculture, it is recommended to cultivate (for two to three years) a pure grass stand of red clover, as well as a three-species stand including clover, alfalfa and timothy (six to seven years). In а pasture, legume-cereal perennial grass stands accumulate in the soil up to 9.0 ton/hectare of mowing root residues, total nitrogen content being up to 113.0 kg/ha over a five-year period, thus contributing to a slight increase in humus content and a decrease in soil acidity.

Achieving the dual goals of biomass production and soil rehabilitation with sown pasture on marginal cropland: Evidence from a multi-year field experiment in Northeast Inner Mongolia.

Grassland is the primary land use in China but has experienced severe degradation in recent decades due to overgrazing and conversion to agricultural production. Here, we conducted a field experiment in northeastern Inner Mongolia to test the effectiveness of sown pastures in lowering the grazing pressure on grasslands and raising the quality of marginal soils. Alfalfa and smooth bromegrass monocultures and mixture were sown in a marginal cropland field in Hulunber in June 2016. Biomass productivity, soil physicochemical, and biological properties were monitored annually from 2016 to 2020. The results showed that the marginal cropland soil responded consistently positively to sown pastures for major soil properties. Soil organic carbon (SOC) and total nitrogen (TN) increased by 48 and 21%, respectively, from 2016 to 2020 over the 0-60 cm soil depth range. Soil microbes responded proactively too. The soil microbial biomass C (SMBC) and N (SMBN) increased by 117 and 39%, respectively, during the period of 2016-2020. However, by the end of the experiment, the soil of a natural grassland field, which was included in the experiment as a control, led the sown pasture soil by 28% for SOC, 35% for TN, 66% for SMBC, and 96% for SMBN. Nevertheless, the natural grassland soil’s productive capacity was inferior to that of the sown pasture soil. The average aboveground biomass productivity of sown pastures was measured at 8.4 Mg ha-1 in 2020, compared to 5.0 Mg ha-1 for natural grassland, while the root biomass of sown pastures was averaged at 7.5 Mg ha-1, leading the natural grassland by 15%. Our analyses also showed that the sown pastures’ biomass productivity advantage had a much-neglected potential in natural grassland protection. If 50% of the available marginal cropland resources in Hulunber under the current environmental protection law were used for sown pastures, the livestock grazing pressure on the natural grasslands would decrease by a big margin of 38%. Overall, these results represent systematic empirical and analytical evidence of marginal cropland soil’s positive responses to sown pastures, which shows clearly that sown pasture is a valid measure both for soil rehabilitation and biomass production.

Alfalfa-grass mixtures reduce greenhouse gas emissions and net global warming potential while maintaining yield advantages over monocultures

Improving forage productivity with lower greenhouse gas (GHG) emissions from limited grassland has been a hotspot of interest in global agricultural production. In this study, we analyzed the effects of grasses (tall fescue, smooth bromegrass), legume (alfalfa), and alfalfa-grass (alfalfa + smooth bromegrass and alfalfa + tall fescue) mixtures on GHG emissions, net global warming potential (Net GWP), yield-based greenhouse gas intensity (GHGI), soil chemical properties and forage productivity in cultivated grassland in northwest China during 2020–2021. Our results demonstrated that alfalfa-grass mixtures significantly improved forage productivity. The highest total dry matter yield (DMY) during 2020 and 2021 was obtained from alfalfa-tall fescue (11,311 and 13,338 kg ha−1) and alfalfa-smooth bromegrass mixtures (10,781 and 12,467 kg ha−1). The annual cumulative GHG emissions from mixtures were lower than alfalfa monoculture. Alfalfa-grass mixtures significantly reduced GHGI compared with the grass or alfalfa monocultures. Furthermore, results indicated that grass, alfalfa and alfalfa-grass mixtures differentially affected soil chemical properties. Lower soil pH and C/N ratio were recorded in alfalfa monoculture. Alfalfa and mixtures increased soil organic carbon (SOC) and soil total nitrogen (STN) contents. Importantly, alfalfa-grass mixtures are necessary for improving forage productivity and mitigating the GHG emissions in this region. In conclusion, the alfalfa-tall fescue mixture lowered net GWP and GHGI in cultivated grassland while maintaining high forage productivity. These advanced agricultural practices could contribute to the development of climate-sustainable grassland production in China.

Evaluation of Alfalfa and Grass Species in Binary and Complex Mixtures on Performance under Soil Salinity Conditions

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.

Grasses and field crops reduce the concentration of resting spores of Plasmodiophora brassicae in soil under controlled conditions

AbstractClubroot, caused by Plasmodiophora brassicae, dramatically reduces yields of brassica crops, and once present in a field, can persist in the soil for many years via long‐lived resting spores. Some nonhost crops can stimulate the germination of resting spores, which reduces clubroot inoculum because the pathogen cannot complete its life cycle in the absence of a living host. The effect of selected grasses and other field crops on the concentrations of spores in soil was assessed in two replicated and repeated short‐duration (8‐week) studies under controlled conditions. The spore concentration declined precipitously in the bare soil control relative to the initial spore concentration over the course of both studies. Cultivars of meadow bromegrass, smooth bromegrass and one cultivar of perennial ryegrass reduced the spore concentration compared to the bare soil control in both repetitions of one study, while two cultivars of perennial ryegrass did not reduce the spore concentration. In a second study, spring wheat, perennial ryegrass, barley and field pea reduced spores compared to the bare soil control, but soybean did not. Our hypothesis that larger root systems would produce larger reductions in spore numbers was not supported; there was no correlation between root weight and reduction in spore concentration. We conclude that perennial grasses, spring cereals and field pea can contribute to the reduction of clubroot spores in soil. The advantage of grass crops over annual crops for clubroot management is that movement of infested soil is minimized over the entire duration of the grass stand.

Production cow-calf responses from perennial forage-based and integrated beef-cropping systems.

An experiment was conducted to measure production responses of an alternative cow-calf production system integrated into a cropping system without access to perennial forage compared to a traditional cow-calf system utilizing perennial forage. Multiparous, cross-bred beef cows (n = 160; average age = 6.2 ± 2.8 yr) were utilized in a randomized complete block experimental design and unstructured treatment design. Upon initiation, cows were blocked by age and stratified by source, assigned randomly to one of two production systems, each with four replicates (n = 20 cows/replicate). Once allotted to their treatment groups, cows remained in their experimental units for the duration of the experiment. Treatments were: 1) a traditional system consisting of April to May calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to August calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). There were no differences (P ≥ 0.27) in calving rates (91.8 vs. 86.7 ± 2.92%), pregnancy rates (89.3 vs. 89.9 ± 2.66%), and weaning rates (87.2 vs. 82.3 ± 3.29%) for TRAD vs. ALT, respectively. However, there was an increase (P = 0.04) in the rate of twin offspring in ALT (2.9 vs. 9.4 ± 2.36% for TRAD vs. ALT, respectively). One calf from the set of twins was selected randomly at birth to be removed from the experiment, so the production data are only from single calves. There was no difference (P = 0.47) in calf body weight at birth (40 vs. 39 ± 0.7 kg for TRAD vs. ALT, respectively). At weaning, calves in the ALT system were lighter (P < 0.01) at the same day of age (184 vs. 229 ± 5.5 kg) compared to TRAD calves. Cows from the ALT system had fewer (P < 0.01) kg weaned per cow exposed to bull (150 vs. 199 ± 7.2 kg) compared to TRAD cows. Apart from the twinning rate, no differences in reproductive performance were observed among systems. However, reduced weaning weights and kilogram of weaned calf per cow exposed may negatively impact revenue to the cow-calf enterprise of the ALT system.

Evaluation of harvest time effects on the combustion quality of warm- and cool-season perennial grasses in two contrasting semi-arid environments

In order to achieve economically viable and sustainable solid biofuel production from perennial grasses, high biomass productivity must be complemented by good combustion quality. The aim of this research was to compare the combustion quality of 7 cool-season perennial grasses, comprising bulbous canary grass, reed canary grass, smooth brome grass, orchard grass, tall wheatgrass, tall fescue, and perennial ryegrass, and 3 warm-season perennial grasses, comprising switchgrass, miscanthus, and giant reed, over 2 harvest times (autumn, winter/early spring) in 2 contrasting semi-arid environments (Adana, and Cankiri, Turkey). Delaying the harvest from the autumn to the winter or the spring significantly increased the lignin contents of each of the 3 warm-season grasses and generally decreased the contents of all of the minerals, except for Al and Fe, in miscanthus and switchgrass, and K and Na in giant reed, at both locations. Similar trends were also generally observed for all of the cool-season grasses, except for the orchard grass that was grown in Cankiri. Additionally, delayed harvest resulted in lower slagging tendency and sintering risk in all of the perennial grass species, except for giant reed in Cankiri. However, the autumn harvest caused significantly higher lignin, but generally lower N, P, K, Ca, S, Si, Al, and Fe contents, slagging tendency, and sintering risk in most of the cool-season grasses that were grown in Adana. On the other hand, despite the autumn harvest in Adana, and the spring harvest in Cankiri provided a substantial improvement in combustion quality of the cool-season grasses, mainly due to the reduced mineral and increased lignin contents, they still exhibited relatively lower combustion quality than miscanthus and switchgrass, especially in Adana. These results showed that further effort is needed to improve the combustion quality of cool-season grasses in order for them to be primary biomass feedstock alternatives for dry marginal lands of semi-arid environments.

Full-Length Transcriptomics Reveals Complex Molecular Mechanism of Salt Tolerance in Bromus inermis L.

Bromus inermis L. (commonly known as smooth bromegrass) is a grass species with high nutritional value, great palatability, cold tolerance, and grazing resistance, which has been widely cultivated for pasture and sand fixation in northern and northwestern China. Salt stress is a main environmental factor limiting growth and production of smooth bromegrass. In this study, we performed PacBio Iso-Seq to construct the first full-length transcriptome database for smooth bromegrass under 300 mM NaCl treatment at different time points. Third-generation full-length transcriptome sequencing yielded 19.67 G polymerase read bases, which were assembled into 355,836 full-length transcripts with an average length of 2,542 bp. A total of 116,578 differentially expressed genes were obtained by comparing the results of third-generation sequencing and second-generation sequencing. GO and KEGG enrichment analyses revealed that multiple pathways were differently activated in leaves and roots. In particular, a number of genes participating in the molecular network of plant signal perception, signal transduction, transcription regulation, antioxidant defense, and ion regulation were affected by NaCl treatment. In particular, the CBL-CIPK, MAPK, ABA signaling network, and SOS core regulatory pathways of Ca2+ signal transduction were activated to regulate salt stress response. In addition, the expression patterns of 10 salt-responsive genes were validated by quantitative real-time PCR, which were consistent with those detected by RNA-Seq. Our results reveal the molecular regulation of smooth bromegrass in response to salt stress, which are important for further investigation of critical salt responsive genes and molecular breeding of salt-tolerant smooth bromegrass.

Lucerne Proportion Regulates Competitive Uptake for Nitrogen and Phosphorus in Lucerne and Grass Mixtures on the Loess Plateau of China

Mixtures of legume and grass are used worldwide to gain advantages in forage production and ecological maintenance. However, competition for nutrients by legumes in mixtures has not been fully explored. The aim was to determine how the forage proportion affected nutrient competition in legume and grass mixtures. Treatments included two species combinations and five sowing ratios. Competitive ratios (CR) of lucerne for nitrogen (N) and phosphorus (P) over two grasses were assessed to analyze how the lucerne proportion in mixtures affected the competition. Total N and P uptake were mostly lower under timothy-containing mixtures (MPs) than under smooth bromegrass-containing mixtures (MBs). Proportions of both N (NM%) and P uptake (PM%) of lucerne were higher under MPs than under MBs. Higher total N and P uptake were found under half-lucerne mixtures (M5P5 or M5B5) than under other grasslands. The NM% and PM% tended to be higher under half-lucerne mixtures, although they showed little difference among mixtures. Lucerne CR was greater under MPs than under MBs, and was greater than grass CR when lucerne was in lower proportion in the mixtures. There was little difference in soil N density among grasslands of the same cut, whereas soil P density was variable. Competitiveness of lucerne depends largely on the initial sowing ratio. High ratios of lucerne significantly reduce soil P density, leading to P limitation and reduced N and P uptake. On the Loess Plateau of China, mixing lucerne with smooth bromegrass is recommended to increase the uptake and harvest of N and P, specifically at the sowing ratio of 5:5.

Interseeding legumes into established semiarid smooth bromegrass pasture

AbstractSeeding legumes into established cool‐season grass pasture helps to lower the long‐term costs of production and may improve total forage yield and quality, but seeding these legumes in the semiarid Central Great Plains region is often ignored. Eight legumes commonly seeded in the Midwest and eastern USA were no‐till seeded in late winter into upland and lowland west‐central Kansas smooth bromegrass (Bromus inermis Leyss.) pastures. Purple‐flowered alfalfa (Medicago sativa L. ssp. sativa) and yellow‐flowered alfalfa [Medicago sativa L. ssp. falcata (L.) Arcang.] established well at the lowland and upland sites and helped improve forage yield compared with nitrogen‐fertilized smooth bromegrass. Korean lespedeza [Kummerowia stipulacea (Maxim.) Makino] and yellow sweetclover [Melilotus officinalis (L.) Lam.] established well on both landscape sites, but these legumes declined significantly over time and did not increase forage yield compared with smooth bromegrass alone. Legume establishment was greater in unfertilized smooth bromegrass at each landscape, indicating that early competition from the grass limited legume establishment. Purple‐flowered and yellow‐flowered alfalfa increased the crude protein concentration compared with smooth bromegrass alone on the lowland site, and increased crude protein and total digestible nutrient concentration on the upland site. Birdsfoot trefoil (Lotus corniculatus L.), cicer milkvetch (Astragalus cicer L.), and hairy vetch (Vicia villosa Roth) failed to establish with competition from smooth bromegrass at the upland and lowland sites. Purple‐flowered and yellow‐flowered alfalfa may establish and persist when seeded into existing smooth bromegrass pastures in the drier regions of central Kansas while increasing forage yield and nutritive value.

Nitrogen fertilizer rate and timing effects on smooth bromegrass interseeded with sorghum‐sudangrass

AbstractInterseeding perennial cool‐season grass pastures with annual warm‐season grasses may increase forage accumulation and nutritive value. Our understanding of how N fertilizer rate and timing affect the forage mass, herbage composition, and N use efficiency (NUE) of interseeded pastures remains limited. In 2018–2020, we evaluated the responses of smooth bromegrass (Bromus inermis Leyss.) to two interseeding and five fertilizer rate and timing treatments in eastern Nebraska. Interseeding treatments included unseeded smooth bromegrass and smooth bromegrass interseeded with sorghum‐sudangrass [Sorghum bicolor (L.) Moench × S. bicolor var. sudanense]. Fertilizer rate and timing treatments included: 0 lb N acre–1, 80 lb N acre–1 in spring, 40 lb N acre–1 in spring and summer, 80 lb N acre–1 in summer, and 80 lb N acre–1 in spring and summer. Summer applications occurred after sorghum‐sudangrass emergence. Across years, fertilizer rate and timing had the greatest effects on forage and weed responses. Applying N at 80 lb acre–1 in spring increased spring and total spring + summer forage mass by 33% while increasing NUE compared with summer application. Interseeding did not increase summer and total forage mass, and summer N applications did not enhance the success of sorghum‐sudangrass and were problematic, increasing weediness and reducing NUE. Practitioners should fertilize smooth bromegrass with 80 lb N acre–1 in spring or 40 lb N acre–1 in split spring and summer applications in eastern Nebraska. Interseeding sorghum‐sudangrass may increase forage accumulation and nutritive value, but establishment methods need improvement.

Responses of Seed Yield Components to the Field Practices for Regulating Seed Yield of Smooth Bromegrass (Bromus inermis Leyss.)

Agronomic practices improve seed yield by regulating seed yield components, and the relationship between seed yield and seed yield components is still unclear in smooth bromegrass (Bromus inermis). To optimize seed production and yield in smooth bromegrass, a five-year field trial was designed with split-split-plot to study the combined effects of row spacing (30, 45, 60, and 75 cm), phosphorus (0, 60, 90, and 120 kg P ha−1) and nitrogen (0 and 100 kg N ha−1) on seed yield and seed yield components including fertile tillers m−2 (FTs), spikelets per fertile tiller (SFT), florets per spikelet (FS), and seeds per spikelet (SS). The results showed that FTs as a key factor had a positive effect to seed yield with the biggest pathway coefficient, while SS had a negative effect. Meanwhile, an interaction effect between FTs and SS was observed. FS and SS were increased with phosphorus application under the condition of sufficient nitrogen. In addition, sufficient precipitation at the non-growing season resulted in more FTs in the next year in rain-fed regions. Therefore, the optimum seed yield of smooth bromegrass can be obtained with row spacing (45 cm), nitrogen (100 kg N ha−1), and phosphorus application (60 kg P ha−1).

Drought Resistance and Resilience of Non-Native versus Invaded-Native Grassland in the Northern Tallgrass Prairie

In the North American Northern Great Plains, Kentucky bluegrass (Poa pratensis L.) and smooth bromegrass (Bromus inermis Leyss. subsp. inermis) pose a serious threat to native grassland integrity and function. This study's objectives were to 1) determine drought resistance of non-native grassland and invaded-native tallgrass prairie during 1 and 2 yr of drought and 2) determine drought resilience of non-native grassland and invaded-native tallgrass prairie after 1 yr of drought and 1 yr of recovery with 100% of average precipitation. Three rainout shelters, 3.6 m x 4 m, were installed on non-native and invaded-native grassland in eastern South Dakota to simulate drought conditions by excluding ambient rainfall. The shelter system was constructed on a track whereby the shelter automatically moved over the experimental plots when it rained and moved away from the plots when it stopped raining. Weekly watering treatments consisted of ambient, 75%, 100%, 125%, and 250% of the 30-yr average in 2013 and 2014 (Experiment I). Also, in 2014 a second set of the 75%, 100%, and 125% watering treatments were watered to 100% of the 30-yr average (Experiment II). Drought reduced biomass production in both non-native and invaded-native grassland sites. When plots were watered to 100% of the 30-yr average, the non-native site had similar amount of biomass compared with the drought year, but the invaded-native site had lower biomass. This response provides more evidence regarding the aggressive nature of these two introduced cool-season grasses and a mechanism to explain their continual dominance and expansion in this region.

First report of bacterial leaf streak caused by Xanthomonas translucens pv. undulosa on cultivated wild rice (Zizania palustris) in Minnesota.

Known by the indigenous peoples of the Great Lakes region of North America as Manoomin, wild rice (Zizania palustris) is a native aquatic grass that is honored and central to Anishinaabe culture. Cultivated wild rice, the domesticated form of this cereal bred primarily for resistance to shattering, is grown commercially in paddies. In this study we examined four isolates (CIX303, CIX306, Xt-8, and Xt-22) of Xanthomonas translucens, the causative agent of bacterial leaf streak (BLS) on cereals and weedy grasses, in molecular and host range studies to confirm the pathovar identity of strains associated with cultivated wild rice. Two of the strains examined (CIX303 and CIX306), were isolated from cultivated wild rice in 2016 as part of a survey of the pathogen in Minnesota (Ledman 2019). Xt-8 and Xt-22 are historical strains of X. translucens isolated from symptomatic wild rice leaves collected in Minnesota in the late 1970s that were reported at the time to be X. campestris pv. cerealis (Bowden and Percich 1982). A host range assay was repeated twice in the greenhouse, where two leaves of six seedlings each of hard red spring wheat (cv. RB07), spring barley (cv. Quest), spring rye (cv. Prolific), oat (cv. Ogle), quackgrass, smooth brome grass and cultivated wild rice (cv. Itasca Cycle-12) were inoculated via leaf infiltration (Curland et al. 2020). X. translucens pv. cerealis LMG 679PT, X. translucens pv. secalis LMG 883PT, X. translucens pv. translucens LMG 876T, and X. translucens pv. undulosa LMG 892PT were included as reference strains. Host response profiles were determined for each strain by recording character states five days post inoculation. Water-soaking and necrosis were considered pathogenic reactions, whereas chlorosis was not. Three pathotype strains, LMG 679PT, LMG 876T, and LMG 892PT, caused water-soaking in cultivated wild rice, whereas LMG 883PT caused chlorosis. All four strains from cultivated wild rice produced water-soaking on wheat, barley, quackgrass, and cultivated wild rice, chlorosis or water-soaking on rye, chlorosis on oat, and a reddish water-soaking on smooth brome. The character states generated by these four isolates were identical only to the host response profile for LMG 892PT. LMG 679PT differed, causing chlorosis on wheat, no symptoms on quackgrass, and water-soaking on smooth brome. A 2645 bp concatenation of housekeeping genes (rpoD, dnaK, fyuA, gyrB) was used to perform a Bayesian analysis (GenBank accessions MW528365-MW528384) (Curland et al. 2018, Curland et al. 2020, Young et al. 2008). Subsequent phylogenies grouped all four strains from cultivated wild rice with LMG 892PT and LMG 883PT. A pairwise comparison revealed 100% identity between Xt-22 and LMG 892PT. The percentage identity of CIX303, CIX308, and Xt-8 to LMG 892PT was 99.96, 99.96, and 99.92, respectively. In contrast, when compared to LMG 679PT, the four strains from cultivated wild rice had a percent identity between 97.43 and 97.50. Based on host range studies combined with MLSA, we identified recent and historical isolates from Z. palustris as X. translucens pv. undulosa. Pathovar identity of strains causing BLS on cultivated wild rice in Minnesota is crucial when screening breeding materials for disease resistance. Furthermore, given that X. translucens pv. undulosa has been prevalent on wheat in Minnesota (Curland et al. 2018), expanding knowledge of its host range to include cultivated wild rice may inform disease management practices for both crops.

Продуктивність сіяних лучих травостоїв залежно від елементів технології вирощування

The results of research on the influence of species composition of grass mixtures, the level of fertilizing, and growth stimulator Fumar on the productivity of sown meadow herbage on typical low-humus chernozems of the Right-Bank Forest-Steppe are presented. The experimental part of the work was performed in the scientific laboratories of the Forage Production, Land Reclamation, and Meteorology Department in the production unit of the National University of Life and Environmental Sciences of Ukraine "Agronomic Research Station". The territory of the research station is located in the Right-Bank Forest-Steppe and is a part of Bila Tserkva agro-soil district. The experimental plots were laid on typical low-humus chernozems, coarse-grained light loam in terms of mechanical composition, which are characterized by a high content of gross and mobile forms of nutrients. The climate of the region is characterized by unstable humidity and moderate temperatures. The average annual air temperature is 6-8 ° C. The annual amount of precipitation reaches 562 mm, during the growing season - 354-394 mm (63-70% of the annual norm), which falls unevenly throughout the year. The purpose of the study is to establish patterns of high productivity formation of sown perennial grasses depending on the species composition and fertilizers on typical low-humus chernozems of Right-Bank Forest-Steppe. The analysis of fertilizers effect showed that the highest productivity on all stands was provided by the combined application of complete mineral fertilizer and biostimulator of growth Fumar (N60P60K90 + Fumar), where productivity compared to the option without fertilizer on average over the years of research on alfalfa t/ha of dry mass or by 9%, on its mixtures with cereals - by 0.89–1.19 t/ha, or by 9–11%, and on cereal herbages - by 2.79 t/ha, or by 54% at LSD 0.41 t/ha. Productivity from the use of growth stimulant Fumar increased by 0.27-0.32 t/ha of dry weight or 2-4% and depended a little on the species composition of herbages. High efficiency of alfalfa inclusion in leguminous-cereal grass mixtures, as well as use of single-species alfalfa sowing for fodder purposes, especially on backgrounds without mineral nitrogen, was revealed. The productivity of these herbages in comparison with cereal herbages on nitrogen-free backgrounds (variants without fertilizers and P60K90) on average for 2014–2016 increased from 3.74–4.10 to 8.06–8.68 t/ha of fodder units, from 0.57-0.66 to 1.70-1.96 of crude protein, from 93.7-101.4 to 182.1-206.2 GJ/ha of gross energy and from 38.9-42.7 to 82.4–91.3 GJ/ha of metabolic energy or by1.8–3.0 times, while on backgrounds with nitrogen application (variants N60P60K90 and N60P60K90 + Fumar) - respectively from 5.73–5.93 to 8, 27–9.22 t/ha, from 1.13–1.21 to 1.89–2.29 t/ha, from 139.8–144.8 to 192.5–219.1 GJ/ha, and from 59.6–61.7 to 89.4–98.2 GJ/ha, or by 1.4–1.6 times. Comparison of the productivity of alfalfa-cereal mixtures with single-species sowing of alfalfa shows that on the same backgrounds it was at the same level with slight fluctuations. On average, in the first three years of use, the most influential factor in the yield of 1 ha of dry mass is the factor of grass cover with a share of 60%. The share of fertilizer factor is 40%. The inclusion of alfalfa in legumes and cereal mixtures, as well as the use of single-species sowing for fodder purposes compared to cereals in the background without mineral nitrogen on average for the first three years of use, increases the productivity of sown grasslands from 5.12-5.54 to 10,44–10.78 t/ha of dry weight, from 3.74–4.10 to 8.06–8.68 t/ha of feed units, from 0.57–0.66 to 1.70 1.96 of crude protein and from 38.9–42.7 to 82.4–91.3 GJ/ha of exchange energy or by 1.8–3.0 times, while on backgrounds with N60 application - from 7.28–7.59, respectively, to 9.42–9.71 t/ha, from 5.73–5.93 to 8.27–9.22 t/ha, from 1.13–1.21 to 1.89–2.29 t/ha and from 59.6–61.7 to 89.4–98.2 GJ/ha, or only by 1.4–1.6 times. Among the alfalfa-cereal herbages in the first two years of use, the most productive was the agrocenosis, the cereal part of which is represented by smooth bromegrass and English bluegrass. The lowest, but quite high productivity of alfalfa and alfalfa-grass herbages is provided without fertilizers, which on average for the first three years of use ranges from 9.95 to 10.86 t/ha of dry weight, 1.70 to 1.85 t/ha of crude protein, 82.4–85.8 GJ/ha of metabolic energy, while cereals, respectively, 5.12 t/ha, 3.74 t/ha, 0.57 t/ha, 38.9 GJ/ha.