Alfalfa Grass Research Articles

Effects of intravenous lipopolysaccharide administration on feed intake, ruminal forage degradability, and liquid parameters and physiological responses in beef cattle

This experiment compared DMI, ruminal forage degradability, and liquid parameters as well as physiological responses in beef cattle receiving a lipopolysaccharide (LPS) challenge or not. Eight ruminally cannulated Angus × Hereford steers (485 ± 16 kg BW) were housed in individual pens on d −7, ranked by BW, and allocated to 1 of 2 treatments administered on d 0: 1) an intravenous (i.v.) bolus dose (0.5 μg/kg of BW, diluted in 5 mL of 0.9% sterile saline) of bacterial LPS (Escherichia coli 0111:B4) or 2) a 5-mL i.v. injection of 0.9% sterile saline (CON). Steers had free-choice access to mixed alfalfa–grass hay, water, and a commercial vitamin + mineral mix during the experiment (d −7 to 6). Hay DMI was evaluated daily from d −5 to 6. Immediately prior to treatment administration (h 0), polyester bags containing 4 g of ground dietary hay (DM basis) were immersed into the rumen of each steer and incubated for 0, 4, 8, 12, 24, 36, and 48 h for DM and NDF degradability evaluation. Steers were also intraruminally pulse-dosed with 5 g of Co-EDTA immediately prior to treatment administration, and rumen fluid samples were collected at 0, 2, 4, 6, 8, 12, 16, and 24 h for ruminal liquid volume and dilution rate calculations. Blood was collected every 2 h from −2 to 8 h, every 4 h from 8 to 16 h, every 12 h from 24 to 72 h, and every 24 h from 96 to 144 h relative to treatment administration. Values obtained before treatment administration were used as a covariate within each respective analysis. Steers receiving LPS had less (P ≤ 0.03) DMI on d 0 and 1 compared with CON steers. Steers receiving LPS had reduced (P ≤ 0.05) rumen liquid volume and dilution rate as well as ruminal disappearance rate and effective degradability of DM and NDF compared with CON steers. Steers receiving LPS had greater (P ≤ 0.05) plasma tumor necrosis factor α at 2 h, greater plasma haptoglobin from 24 to 72 h, greater plasma cortisol from 12 to 16 h, greater serum NEFA from 6 to 48 h, greater plasma insulin and glucose at 2 h, reduced plasma glucose from 4 to 12 h, greater plasma cholecystokinin at 16 h, and greater plasma leptin concentrations at 8, 12, 16, 36, 48, and 60 h after treatment administration compared with CON steers. Hence, LPS administration transiently reduced DMI in steers via physiological reactions that modulate gastrointestinal motility and satiety centers in the central nervous system, in addition to potential host–microbiome endocrine interactions that impaired ruminal hay DM and NDF degradability.

Fattening rabbits in mobile arks: effect of housing system on in vivo oxidative status and meat quality

<p>The aim of this trial was to study the effect of an alternative housing system on the oxidative status and meat quality of fattening rabbits. From May to June 2014, 60 rabbits of 35 d of age were reared in Mobile Arks (MA) placed on alfalfa grass and frequently moved for 40 d. To assess the health status of animals, blood samples were collected at slaughter in MA and in conventional cages (C). Meat quality parameters were also evaluated. Concerning the <em>in vivo </em>oxidative status, ark-reared rabbits showed higher thiobarbituric reactive substances values than C ones, probably for the higher motor activity due to the larger living area. The lipid percentage of <em>Longissimus lumborum </em>muscle was lower (1.22 <em>vs. </em>1.48%) in the ark group. There were no significant differences in the muscle pH, colour, water holding capacity and cooking loss. Given the higher intake of grass, rich in vitamins, carotenes, polyphenols and polyunsaturated fatty acids, the antioxidant content of meat was higher in ark-reared rabbits (7.42 <em>vs. </em>6.82 µg/g of retinol, 719.2 <em>vs. </em>683.3 ng/g of α-tocopherol, respectively). Even the fatty acid profile of MA rabbits reflected the higher intake of essential fatty acids from grass and the n-3 long chain polyunsaturated fatty acids (arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid) were almost doubled. Our study suggested that the fattening of rabbits in ark system could be a possible alternative system to improve the meat quality of rabbits.</p><p><strong><br /></strong></p>

Root traits of cup plant, maize and lucerne grass grown under different soil and soil moisture conditions

AbstractThe cup plant (Silphium perfoliatum L.) is presently discussed as a promising alternative to silage maize for biomethane production in Germany. It is assumed that the cup plant develops a profound root system, contributing decisively to the drought tolerance of this crop. This study is aimed at providing the first experimental data on root growth and water uptake of this novel biogas crop. Root morphological characteristics of the cup plant were studied at six sites differing in soil type. Root samplings were made at the time of maximum root expansion (flowering). In a 2‐year field experiment at an additional location, continuous measurements of root development and soil water acquisition during the growth cycle were taken under contrasting water supply, together with maize (Zea mays L.) and lucerne grass (mixture of Medicago sativa L. with Festuca pratensis Huds. and Phleum pratense L.) as reference crops. The cup plant attained maximum rooting depths of 80–240 cm. The root length density was comparable to that of maize, but markedly lower than that of lucerne grass. Despite the cup plant's higher potential evapotranspiration and similar water‐use efficiency, its soil water extraction ability was significantly lower than that of lucerne grass. Compared with maize and lucerne grass, the cup plant showed no outstanding ability to cope with drought stress by means of its root system. Because of its high potential evapotranspiration, the cup plant can attain biomass yields comparable to those of maize only at sites with high water supply.

Botanical Composition Prediction of Alfalfa–Grass Mixtures using NIRS: Developing a Robust Calibration

Botanical composition of alfalfa (Medicago sativa L.)–grass fresh and ensiled mixtures is a key parameter for assessing forage and diet quality as well as for managing mixed stands. Previous attempts to validate near‐infrared reflectance spectroscopy (NIRS) equations for estimating botanical composition have had mixed results. This study was conducted to develop a robust NIRS method to estimate botanical composition of binary alfalfa–grass mixtures. Alfalfa–grass samples were collected across New York State over four growing seasons, hand separated, and a subset were ensiled separately. Dry samples were coarsely ground, mixed in known proportions, and reground for analysis by NIRS at Dairy One Forage Laboratory, Ithaca, NY. Samples were mixed to range from 0 to 100% alfalfa for NIRS calibration, with a total of 741 individual samples from 3 yr used for calibration of three NIRS instruments and samples from a fourth year used for validation. Grass composition was predicted with good precision and accuracy showing biases of 2.49 and standard errors of prediction (SEP) of 5.06, with R2 of 0.972, using the equation developed across multiple instruments. With selection of a robust set of calibration samples over many environments, NIRS can be used to determine the botanical composition of fresh‐dried or ensiled‐dried alfalfa–grass samples, and replicate scans from multiple instruments can be combined to develop a single calibration that will perform with equal efficiency across different instruments.

Quantification of Agricultural Water Productivity at Field Scale and Its Implication in On-Farm Water Management

The Kingdom of Saudi Arabia (KSA) is under extreme water shortage conditions. About 80 % of water in KSA is utilized by the agricultural sector; therefore, proper management of irrigation water is required to produce more food from less water. Water productivity concept was emerged and successfully quantified with the use of remote sensing as well as variable-rate application technologies. In this study, water productivity (WP) of three major crops (alfalfa, corn and Rhodes grass), cultivated in the Eastern Province of KSA under center pivot irrigation system, was estimated using Landsat-8 images in conjunction with in situ field observations. Evapotranspiration (ET)/water use maps (WUM) of irrigated fields was generated from Landsat-8 data using SEBAL model. Subsequently, the crop type and growth stage wise amount of water required for the irrigation was estimated and the irrigation schedules were prepared. Zone based Variable Rate Irrigation (VRI) system was used to optimize the application of irrigation water. Classified ET maps are used as a base for the formulation of prescription map for VRI. The accuracy of SEBAL derived ET maps were assessed against the actual ET recorded by the Eddy Covariance (EC) flux tower installed on an alfalfa field. Crop Productivity Map (CPM) of alfalfa and Rhodes grass were developed using hay yield monitor data, while forage corn productivity was represented by the relationship between the NDVI and sampled silage corn yield (kg m−2). Water productivity map was generated by dividing the CPM with the WUM. The deviation between SEBAL predicted and EC flux tower recorded ET was ranged from 2.92 to 7.13 %. The mean predicted yield (kg ha−1) of alfalfa, corn and Rhodes grass was 2934, 4650 and 3368, respectively. The fields with remote sensing (RS) and VRI application was shown higher WP compared to without RS and VRI inputs. The recorded WP of silage corn, Rhodes grass and Alfalfa with RS and VRI inputs was 1.09, 0.81 and 0.83 respectively, whereas, it was decreased to 1.03, 0.64 and 0.61 kg m−3 respectively for the fields without RS and VRI inputs.

Uptake and translocation of sulfamethazine by alfalfa grown under hydroponic conditions

Antibiotics are routinely used in intensive animal agriculture operations collectively known as Concentrated Animal Feed Operations (CAFO) which include dairy, poultry and swine farms. Wastewater generated by CAFOs often contains low levels of antibiotics and is typically managed in an anaerobic lagoon. The objective of this research is to investigate the uptake and fate of aqueous sulfamethazine (SMN) antibiotic by alfalfa (Medicago sativa) grass grown under hydroponic conditions. Uptake studies were conducted using hydroponically grown alfalfa in a commercially available nutrient solution supplemented with 10mg/L of SMN antibiotic. Analysis of alfalfa sap, root zone, middle one-third, and top portion of the foliage showed varying uptake rate and translocation of SMN. The highest average amount of SMN (8.58μg/kg) was detected in the root zone, followed by the top portion (1.89μg/kg), middle one-third (1.30μg/kg), and sap (0.38μg/kg) samples, indicating a clear distribution of SMN within the sampled regions. The ultraviolet (UV) spectra of parent SMN and translocated SMN identified in different parts of the plant present the possibility of metabolization during the uptake process. Uptake of SMN using alfalfa grown under hydroponic conditions has potential as a promising remediation technology for removal of similar antibiotics from wastewater lagoons.

Study of raw material of alfalfa yellow (like-sickle or Romanian)

Along with the wide distribution and use of alfalfa grass there is no comprehensive scientific pharmacognosy studies about representatives of the plants of this kind. Aim. To study the content of the group of true coumarins and 4-oxyderivatives which presence must be characteristic for the yellow alfalfa. Materials and methods. The determination of diagnostic anatomical features of the plant Medicago falcata L. subsp. romanica (Prodan) O. Schwarz & Klink has been carried out. The leaf petiole has such diagnostic characteristics: elongated epidermal cells, parenchymal or prosenchymal, 4-, or (rarely) 5-6 gonal; pubescence is of simple single-celled hairs with warty cuticle, which can be found on the upper and lower epidermis of the leaf. The stomatas are rare. The rosette is formed from basal epithelial cells near the base of the hairs. Results. 66 Components have been revealed by chromatography of native raw, 38 of components have been identified, namely - dihydrocoumarin (1.60%) and coumarin (13.13%). After the acid hydrolysis 52 components have been revealed, 41 of which have been identified. These substances are the complex of biologically active compounds: primary alcohols, aldehydes, ketones. 4-Oxycumarin derivatives have been identified: coumarin - 79.38% dihydrocoumarin - 4.95%, and 6-methylcoumarin - 0.39%. While studying the amino acid composition of the above-ground parts of alfalfa yellow we got interested in a significant amount of aspartic acid, proline and phenylalanine.

An economic analysis of resting versus nonresting perennial pastures during the critical acclimation period

Economic evaluations were carried out on stochastically simulated production systems using data from a grazing systems’ trial, which evaluated the impact of resting (i.e., grazing cessation) alfalfa (Medicago sativa L.) – bromegrass (Bromus riparius Rehm. ‘Fleet’) and grass-only (G) pastures during the critical prefrost period on beef cattle (Bos taurus) productivity. Grazing systems were compared on the basis of calculated net present value of returns analysis. Lower production costs through reduced fertilization requirements resulted in alfalfa–grass (AG) preference over G pastures, while returns from increased calf sale weights resulted in nonrested systems being preferred over rested systems. However, low presence of alfalfa in the AG pastures likely limited the potential for resting pastures to improve production through increased alfalfa persistence. This evaluation found nonrested grazing of AG pastures to be preferred over other treatments on the basis of increased returns and reduced risk.

Application of local binary patterns in digital images to estimate botanical composition in mixed alfalfa–grass fields

Botanical composition in mixed stands of alfalfa and grass is a critical parameter in equations estimating harvest fiber concentration for dairy rations. Composition is difficult to estimate by visual observation. Digital image analysis in mixed stands could reduce botanical composition uncertainty and improve spring harvest management decisions. Mixed stands were sampled (n=168) in farmers’ fields in Tompkins County, New York in May 2011. A digital image was taken of standing samples at 5-Megapixels resolution using a Canon PowerShot A3100IS, and alfalfa and grass height relationships were recorded. After clipping representative samples at 10-cm above ground level, samples were manually separated into alfalfa (Medicago sativa L.) and timothy grass (Phleum pratense L.), and dried to calculate fractions on a dry matter basis. Uniform rotation invariant local binary patterns (LBP) were extracted from whole images and 64×64pixel tiles, and were used to develop regression equations estimating grass fraction. Tiles were manually classified as alfalfa (0), grass (1) or unclassifiable. An iterative process selected most accurate local binary pattern operator settings. Grass fraction was estimated in three regression model development approaches: (1) using average tile LBP histogram bins from whole images and botanical height relationships, (2) developing a binary tile classification model from tile LBP histogram bins, and using tile model-predicted grass probability averaged for tiles in whole images (grass coverage estimate) and botanical height relationships as inputs in whole image models, and (3) using LBP histogram bins extracted directly from whole images (1024 by 1024pixel square) and height relationships. Predictive accuracy in whole image models using tile LBP histogram averages was highest for models generated from LBP tile histogram bin means (R2pred up to 0.847), followed closely by combined tile models and whole image models (R2pred up to 0.807), with pairwise correlations between tile model-generated grass coverage estimates and sample grass fraction up to 0.895. Local binary patterns are effective in differentiating alfalfa and grass under field conditions, because the method is robust to changes in color and illumination. Furthermore, key LBP histogram bins (e.g., symmetric edges) strongly differentiate alfalfa and grass in tiles. The LBP method is promising based on this study, but further evaluation under diverse field conditions, including different cameras and grass species, is necessary to assess usefulness.

Effects of resting perennial pastures during the sensitive pre-dormancy period in western Manitoba: Pasture productivity and beef cattle performance

Durunna, O. N., Baron, V., Scott, S. L., Robins, C., Khakbazan, M. and Block, H. C. 2015. Effects of resting perennial pastures during the sensitive pre-dormancy period in western Manitoba: Pasture productivity and beef cattle performance. Can. J. Anim. Sci. 95: 129–141. The objective of this experiment was to determine whether avoiding grazing during the sensitive pre-dormancy period (ca. 6 wk prior to a dormancy-inducing frost) would improve forage production, stand quality, alfalfa persistence and animal productivity in perennial pastures. There were two pasture species (PS), alfalfa–grass (AG) or grass (G), and three grazing phases. Phase I was conventional rotational grazing of all AG and G sections. In Phase II, one half of AG and G was rotationally grazed (conventional treatment, CT) while the other half was not (rested treatment, RT). Resting AG and G in Phase II required transferring RT animals to swath-graze early-seeded cereals. In Phase III, RT animals that swath-grazed in Phase II were moved to graze the rested sections of the pastures while those that grazed the unrested sections (CT animals) were transferred to swath-graze late-seeded cereals. There was no PS (P>0.05) or rest period (P>0.13) effect on total forage yield, carrying capacity, forage disappearance and forage residues. There was no effect (P>0.13) of resting on botanical composition or yield in AG. The current study did not observe significant benefits of resting on pasture yield, botanical composition or animal performance.

Small Ruminant Production System Efficiency under Abu-Dhabi, United Arab Emirates Arid Land Conditions

Sheep and goat production systems in the United Arab Emirates (UAE) operate under scarce natural resource constraints. A cross-sectional survey that covered 661 mixed farms, including major sheep and goat production, was conducted in the three regions of Abu Dhabi Emirate (Al-Ain, Western Region and Abu Dhabi city) during 2012. A Cobb-Douglas, double-logarithmic stochastic frontier production function and maximum likelihood estimation were applied to estimate important economic derivatives and the associated risk of small ruminant production in this arid area. The highest impact of an input on the output level was found to be labor for raising sheep and alfalfa grass for raising goats. Both labor and alfalfa variables were found to be overutilized for sheep and goat production, respectively. Overall, the results indicate that average technical efficiency is 0.62 for raising sheep and only 0.34 for raising goats in the study area. Technical efficiency analysis included measuring the frequency of farms at each level of estimated technical efficiency in the range between zero and one. Zero for the technical efficiency coefficient indicates a lack of technical efficiency in resource use. The results of this study indicated that only 1% of the sheep farms show a technical efficiency coefficient of 0.25 or less; the same can be said for 41% of goat producers. However, these technical efficiencies were found to be more than 0.75 for 12% and 5% of the sheep and goat farms, respectively. Overall, goat farming in the UAE was found to be less efficient than sheep production. The results also indicated that flock size and type of breed were the most influential factors relative to other factors, and both show a positive relationship with technical efficiency. Other than flock size, factors, such as owners’ years of experience and management practices, were found to be more influential on goat farming system efficiency relative to sheep farming.

Late summer forage yield, nutritive value, compatibility of warm- and cool-season grasses seeded with legumes in western Canada

Biligetu, B., Jefferson, P. G., Muri, R. and Schellenberg, M. P. 2014. Late summer forage yield, nutritive value, compatibility of warm-and cool-season grasses seeded with legumes in western Canada. Can. J. Plant Sci. 94: 1139–1148. In late summer and fall, quality and quantity of forage are important for weight gain by grazing animals in western Canada. The objective of this study was to evaluate forage nutritive value, dry matter (DM) yield, and compatibility of crested wheatgrass [Agropyron cristatum (L.) Gaertn.], meadow bromegrass (Bromus riparius Rehm.), green needle grass [Nasella viridula (Trin.) Barkworth], northern wheatgrass [Elymus lanceolatus (Scribn. & J. G. Sm.) Gould], western wheatgrass [Pascopyrum smithii (Rydb.) Barkworth & D.R. Dewey], Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski], big bluestem (Andropogon gerardii Vitman), or switchgrass (Panicum virgatum L.) in eight grass monocultures, and their binary mixtures with alfalfa (Medicago sativa L.), sainfoin (Onobrychis viciifolia Scop.), or cicer-milkvetch (Astragalus cicer L.) harvested once in August or September. A field study was conducted over a 7-yr period from 1998 to 2004 near Swift Current (lat. 50°25'N, long. 107°44'W, 824 m elev.), SK, Canada, using a randomized complete block design. Forage DM yield was similar between August and September harvests (P>0.05). Binary mixtures of alfalfa–grass produced highest (P<0.05) DM yield ranging from 2449 to 2758 kg ha−1. The monoculture of crested wheatgrass (2143 kg ha−1), sainfoin with crested wheatgrass (2061 kg ha−1), and cicer-milkvetch with green needle grass (1838 kg ha−1) or cicer-milkvetch with western wheatgrass (1861 kg ha−1) produced the second highest (P<0.05) DM yields in the ranking. The two warm-season grasses produced the lowest (P>0.05) DM yields over the 7-yr period. Monocultures of green needle grass or northern wheatgrass had the highest acid detergent fiber (ADF) and neutral detergent fiber (NDF), while warm-season grasses with legumes had the lowest. Alfalfa with western wheatgrass and alfalfa with Russian wildrye had the highest crude protein (CP) concentrations. Monocultures of meadow bromegrass, crested wheatgrass, green needle grass, or cicer-milkvetch with meadow bromegrass, and sainfoin with crested wheatgrass had the lowest CP concentrations. In vitro organic matter digestibility (IVOMD) was greater for mixtures than for the grass monocultures. Concentration of Ca and P was greater for warm-season grasses than cool-season grasses. Alfalfa with western wheatgrass was the best combination considering yield, quality, and compatibility for deferred grazing in late summer and fall in the semiarid prairies. Tested warm-season grasses are not recommended for seeding as binary mixtures with legumes for southwestern Saskatchewan.

Legume-based forage production systems reduce nitrous oxide emissions

Nitrous oxide (N2O) emissions from agriculture demand attention because they are the main source of total global anthropogenic N2O-emissions. High N-fertilization and soil compaction are important factors that increase N2O-emissions. On intensively managed grassland sites both factors occur. Knowledge of the interaction of high N-fertilization and simultaneous soil compaction on N2O-emissions is therefore essential, but previous studies about this scenario are rare. In the presented study, N-fertilized grass swards (G) and unfertilized lucerne–grass mixtures (LG) were compared over a three-year period (2006–2008): N2O-emissions and dry matter yield were measured as a function of N-fertilization (0 (LG), 360kg Nha−1yr−1 (G) as CAN) and soil compaction (0 (C0), 321kPa (C321)) on a loamy stagnic Luvisol derived from glacial till in northern Germany. CO2-equivalents (CO2eq) per hectare and per unit metabolizable energy (GJ ME) were calculated.N2O-emissions were significantly influenced by the interaction N-fertilization×soil compaction; emissions increased significantly when both factors were induced simultaneously (G/C0: 8.74, LG/C0: 2.46, G/C321: 13.31 and LG/C321: 2.22kg N2O-Nha−1, respectively). Concerning the specific CO2-emissions, expressed in CO2eq (GJ ME)−1, the N-fertilized G swards emitted 67% more CO2eq than LG swards assuming that 50% of the field plots were compacted due to heavy wheel traffic, which are reliable figures from agricultural practice. Neither dry matter (DM) yield nor forage quality (MJ ME (kg DM)−1) differed significantly between fertilized G and unfertilized LG swards. Hence, legume-based instead of fertilizer-based forage production is a promising mitigation option without significant reduction of DM yields. In addition, results regarding soil compaction effects on GHG-emissions emphasize the urgent need to implement controlled traffic systems on intensively managed grassland in order to reduce the area affected by heavy wheel traffic.

In Situ Digestion of Forages and Grains in Alpacas fed Alfalfa and Grass Hay

In situ disappearance of alfalfa hay, grass hay, corn, corn/oats/barley and oat DM and NDF in alpacas fed alfalfa hay (AHF) or grass hay (GHF) was determined in adult male alpacas. The alpacas were then divided into two groups. Alpacas were fed alfalfa hay or grass hay for thirty days prior to the treatments and given water ad libitum throughout. In situ substrates tested included alfalfa hay (AHS), grass hay (GHS), corn (CS), corn/oats/barley/molasses (COBS) and oats (OS). Each forage sample was incubated in each alpaca for 4, 8, 12, 24, 36 and 72 hours and the grain substrates incubated for 2, 4, 6, 12, 24, 36 and 72 hours. Substrate treatments were administered in random order to each alpaca for the two forages fed. Forage residue was analyzed for DM and NDF, and grain residue for DM concentrations. The DM and NDF totals were divided into three categories: a = immediately soluble; b = the non-soluble but degradable; and u = non-degradable/unavailable, potential extent of degradation (PE), degradation rate (c) and effective degradation at 2 %∙hr-1 (ED2) and 4 %∙hr-1 (ED4). All DM parameters were significant for feed substrates (P<0.001). DM c was also significant for forage and the interaction (P<0.001). NDF parameters were only significant for fraction b and PE (P<0.001). Degradation in these alpacas was not different between the two forages provided and although distinct from true ruminants in digestive physiology showed similar digestion parameters for the feed tested.

Forage yield of simple and complex grass–legume mixtures under two management strategies

Foster, A., Vera, C. L., Malhi, S. S. and Clarke, F. R. 2014. Forage yield of simple and complex grass–legume mixtures under two management strategies. Can. J. Plant Sci. 94: 41–50. Limited information is available on the dry matter production, protein content and species composition of complex mixtures of introduced perennial forage crop species for hay and pasture in the moister regions of Saskatchewan. A field experiment was sown on 2008 May 27 at Melfort, Saskatchewan, Canada, on a thick Black Chernozem (Udic Boroll) silty clay soil, to compare the effects on dry matter yield (DMY), protein content and species composition of perennial forage crop monocultures and mixtures, under a two-cut and a three-cut management system, in 2009, 2010, 2011 and 2012. Eleven treatments consisted of monocultures of hybrid bromegrass (Bromus riparius Rehm.×Bromus inermis Leyss.), smooth bromegrass (Bromus inermis Leyss.), crested wheatgrass [Agropyron cristatum (L.) Gaertn], intermediate wheatgrass [Agropyron intermedium (Host.) Beauv.] and alfalfa (Medicago sativa L.); simple mixtures of each of these individual grass species with alfalfa; a more complex mixture of all these grass species and alfalfa, and a very complex mixture consisting of the complex mixture plus meadow bromegrass (Bromus riparius Rehm.), orchardgrass (Dactylis glomerata L.), tall fescue [Festuca arundinacea (Schreb.) Wimm.], timothy (Phleum pratense L.) and slender wheatgrass [Elymus trachycaulus (Link) Gould ex Shinners]. The alfalfa was inoculated with rhizobium, and no fertilizer was added to any treatment during the course of the study. The two-cut system yielded higher than the three-cut system in all years. In 2009, the first cutting year, all treatments, especially under the two-cut system, produced similar forage DMY, with monoculture grasses yielding as much as that of their mixture with alfalfa. In 2010, 2011 and 2012, however, monoculture alfalfa and grass–alfalfa treatments had higher DMY than the monoculture grasses. Monoculture alfalfa also showed superior DMY than most grass–alfalfa mixtures, especially during the last 2 yr of the study. In conclusion, the inclusion of alfalfa in forage mixtures, grown in unfertilized soil, significantly increased forage yield, especially after the first production year, and these grass–alfalfa mixtures yielded almost as much as monoculture alfalfa. Also, the inclusion of alfalfa significantly increased the forage protein content over the grass alone treatments. Hybrid bromegrass, grown alone or in mixture with alfalfa, yielded similar to the other grasses tested, while crested wheatgrass did not compete as well as other main grasses, grown alone or in mixture with alfalfa. In this study, the use of complex or very complex mixtures of introduced grasses with alfalfa did not increase DMY over the simple grass–alfalfa mixtures.

Barley yield and nutrient uptake in rotation after perennial forages in the semiarid prairie region of Saskatchewan

Jefferson, P. G., Selles, F., Zentner, R. P., Lemke, R. and Muri, R. B. 2013. Barley yield and nutrient uptake in rotation after perennial forages in the semiarid prairie region of Saskatchewan. Can. J. Plant Sci. 93: 809–816. Alfalfa (Medicago sativa L.) is the most common perennial forage legume grown for hay and pasture in the semiarid Brown soil zone of the Canadian prairies. Perennial forages often are not recommended for inclusion in annual crop rotations due to lower grain yields and drier soils following forage stand termination, but this is based on research results from 50 yr ago. Three replicated experiments consisting of three grasses [slender wheatgrass (Elymus tracycaulus), intermediate wheatgrass (Elytrigia intermedia), and Dahurian wildrye (Elymus dahuricus)] grown in monoculture and in mixture with two alfalfa varieties (cv. Beaver or cv. Nitro) were terminated and seeded to barley (Hordeum vulgare ‘Harrington’) for 2 consecutive crop years at Swift Current, Saskatchewan. Soil water content was lower after the alfalfa–grass mixtures compared with the grass monocultures, even during a wet growing season. Barley yield and N concentration in the grain were significantly greater following Beaver alfalfa/grass mixture compared with grass monoculture in 3 and 4 of 6 site years, respectively. N uptake by the barley crop (grain and straw) was also significantly greater following Beaver alfalfa/grass mixture than following grass monoculture in all 6 yr. Both barley grain yield and N uptake after intermediate wheatgrass (grown in monoculture) were lower than after Dahurian wildrye or slender wheatgrass in 3 of 6 yr. The use of alfalfa and a short-lived grass species in hay and pasture mixtures in the Brown soil zone when grown in rotation with annual crops may indeed result in lower grain yields in the short term than continuous annual cropping systems, but the inclusion of alfalfa will provide a N benefit to the subsequent grain crop thereby enhancing yield and possibly its market value.

Mechanical Model of Pelletization in the Impressing Roller System

By the force analysis of alfalfa grass powder material layer in work area of circular mould pelletizing system, grass pellet briquetting mechanism when alfalfa grass powder pass work area was explained, function relationship between the thickness of material layer and the circular mould angle was established, force balance equation of material layer differentiation unit under the general conditions was deduced, and the total force of material layer applied by circular mould was obtained. Research result has practical meaning for guiding the process test of grass pellet product and optimizing product structure, and has a certain theoretical reference value for in-depth revealing granulating forming mechanism of hoop standard granulator.

The snails' tale in deep-sea habitats in the Gulf of Cadiz (NE Atlantic)

Abstract. Bridging the Atlantic and Mediterranean continental margins, the South Iberian region has recently been the focus for geological and biological investigations. In this region, the Gulf of Cadiz (GoC) encompasses a great variety of deep-sea habitats that harbour highly diverse biological communities. In this study, we describe the composition of gastropod assemblages obtained from in situ colonization experiments and benthic sampling of deep-sea habitats in the GoC. Gastropod distributional patterns, such as bathymetric ranges, bathymetric turnover, affinity to substrate types and abundance-occupancy relationships, are analysed and interpreted in relation to their inferred dispersal capabilities and substrate availability. Overall, the GoC comprises a high diversity of gastropods (65 species), and distinct assemblages were found in typical sedimentary environments at mud volcanoes and in association with carbonate and coral samples or organic substrata. The number of taxa peaked at the Carbonate Province in the middle slope (600–1200 m depth), a highly heterogeneous area with numerous mud volcanoes, carbonate mounds and corals. Darwin (1100 m) and Captain Arutyunov (1300 m) mud volcanoes harboured the most species-rich and abundant gastropod assemblages, respectively. Colonization experiments with organic substrata (wood and alfalfa grass) also yielded diverse and abundant gastropod assemblages. These organic inputs allowed the recruitment of local species but mainly of wood specialist taxa that were not previously known from the GoC. Our results suggest that the distribution of gastropod assemblages may be primarily determined by the occurrence of suitable habitats, probably due to the effect of the substrate type on the structural complexity of the habitat and availability and diversity of adequate food sources. The type of larval development is apparently not a limiting factor for colonization of deep-sea habitats. However, the predominance of non-planktotrophy, and especially lecithotrophy, suggests that a trade-off between more limited dispersal capability and higher potential for self-recruitment may be a recurrent pattern in gastropod species inhabiting reducing environments and other patchily distributed deep-sea habitats. A network of suitable habitats that ensures effective population connectivity would explain the predominance and relatively wide distribution of short-distance dispersing non-planktotrophic species in the GoC deep-sea habitats and other geographical regions.

Water Use Efficiency by Switchgrass Compared to a Native Grass or a Native Grass Alfalfa Mixture

Perennial grass systems are being evaluated as a bioenergy feedstock in the northern Great Plains. Inter-annual and inter-seasonal precipitation variation in this region will require efficient water use to maintain sufficient yield production to support a mature bioenergy industry. Objectives were to evaluate the impact of a May–June (early season) and a July–August (late season) drought on the water use efficiency (WUE), amount of water used, and biomass production in monocultures of switchgrass (Panicum virgatum L.), western wheatgrass (Pascopyrum smithii (Rydb.) A. Love), and a western wheatgrass–alfalfa (Medicago sativa L.) mixture using an automated rainout shelter. WUE was strongly driven by biomass accumulation and ranged from 5.6 to 7.4 g biomass mm−1 water for switchgrass to 1.06 to 2.07 g biomass mm−1 water used with western wheatgrass. Timing of water stress affected WUE more in western wheatgrass and the western wheatgrass–alfalfa mixture than switchgrass. Water deficit for the western wheatgrass–alfalfa mixture was 23 % lower than western wheatgrass (P = 0.0045) and 31 % lower than switchgrass (P < 0.0001) under the May–June stress water treatment, while switchgrass had a 37 and 38 % greater water deficit than did western wheatgrass or western wheatgrass–alfalfa mixture, respectively (P < 0.001) under the July–August water stress treatment. Water depletion was always greatest in the upper 30 cm. Switchgrass had greater WUE but resulted in greater soil water depletion at the end of the growing season compared to western wheatgrass and a western wheatgrass–alfalfa mixture which may be a concern under multi-year drought conditions.

Cellular Automata based Modeling for the Assessment of Ecohydrological Dynamics at the Hillslope Scale: Preliminary Results

An improved version of a Cellular Automata (CA)-based ecohydrological model developed using a Macroscopic CA approach was applied in a numerical experiment over a large hillslope. The original model was made up of a Vegetation Dynamic Model (VDM) coupled to a Soil–Vegetation–Atmosphere Transfer (SVAT) scheme and to a three-dimensional unsaturated flow and heat diffusion model. It was built in a problem solving environment that uses macroscopic CA both as a tool to model and simulate dynamic complex phenomena and as a computational model for parallel processing. The new version of the ecohydrological model adds flow generation and flow routing modules, allowing to govern liquid water interactions between surface and subsurface domains, to account for depression storage, obstruction storage exclusion and changing surface roughness owing to vegetation dynamics.This paper shows the preliminary results of the analysis of vegetation-hydrology dynamics performed on a ‘reference’ hillslope, with the same morphological characteristics of the Biosphere 2 hillslope experiment, hypothesized fully vegetated with alfalfa grass. Soil moisture and turbulent fluxes spatial and temporal variability was assessed for a period characterized by a single wetting event followed by a dry-down period. The computational performance of the CA-based model allowed a sensitivity analysis over the hillslope, varying both precipitation intensity and soil moisture initial conditions. Surface runoff, soil moisture, evapotranspiration and Leaf Area Index space-time distributions were evaluated for each scenario, highlighting the main differences depending on the changing features of the experiments.