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High-tannin forages can be used to help mitigate the serious limitations associated with gastrointestinal nematode (GIN) infections on efficient small ruminant production. The objective of this experiment was to determine how grazing a GIN-free, established stand of a high-tannin cultivar of birdsfoot trefoil (Lotus corniculatus L.) influenced the prevention or treatment of Haemonchus contortus (Hc) infection in lambs. A birdsfoot trefoil-enriched pasture was established on an area that was previously row cropped and not grazed for at least 15 yr. Treatments included preventative (PREV) with parasite-naive lambs transitioned onto pasture 1 wk prior to receiving an infection of 10,000 Hc larvae, therapy (THER) with parasite-naive lambs infected with 10,000 Hc larvae 4 wk prior to the start of grazing, and control (CONT) with naive, uninfected lambs to verify that natural infection did not occur on pasture. Each treatment group of 12 Suffolk crossbred lambs was divided into 3 replicates per treatment, and all were supplemented with a grain mix to provide 16% CP. Fecal egg count (FEC, eggs/g wet feces) in THER lambs peaked 1 wk after the start of grazing (9,404) and after 4 wk fell to 1,068, equivalent to a FEC reduction of 88.6%. Lambs in PREV had a peak FEC of 4872 at 4 wk after infection where peak FEC was 48% less in PREV than THER lambs. Lambs in CONT did not have measurable FEC for the duration of this study. Packed cell volume (PCV, %) reflected infection status of the lambs in each group, where CONT (32%) had the highest (P < 0.05) PCV followed by THER (29%) and PREV (26%). Total weight gained in CONT lambs was greatest at 5.51 kg (P < 0.01), whereas THER and PREV (2.68 and 2.97 kg, respectively) did not differ. Grazing birdsfoot trefoil-enriched pasture can have both therapeutic and preventative effects on Hc infection in lambs and can be used in a systems approach to control GIN parasites in grazing sheep.

Use of perennial bioenergy grasses would be enhanced if they produced sustainable ratoon crops across a wide geographic region. Our objective was to compare ratoon cold tolerance (defined as shoot emergence during the first-ratoon crop), and plant cane dry mass yield and feedstock quality [acid detergent lignin, cellulose, hemicellulose, total nonstructural carbohydrates (TNC), and combustible energy] of elephantgrass (Pennisetum purpureum), Old World Erianthus (Saccharum arundinaceum, formerly E. arundinaceus, subsequently referred to as Erianthus), and sugarcane (Saccharum sp. hybrids). The experiment (Test 1) was conducted near Booneville, Arkansas (35.08°N latitude) and consisted of three varieties of elephantgrass and Erianthus, and six of sugarcane, evaluated in plant cane (first year growth, 2008) and first-ratoon (second year growth, 2009). The experiment was repeated in 2009–2010 (Test 2). Absolute minimum air temperatures were −12.7 and −17.3 °C in Test 1 and 2, respectively. Second-year emergence in Test 1 was in the order sugarcane = Erianthus (92%) > elephantgrass (25%). In Test 2, sugarcane and Erianthus had 63 and 3% second-year emergence, respectively, whereas elephantgrass shoots did not emerge. Elephantgrass had twice the plant cane yield of the other species. Feedstock quality was generally similar among species, although sugarcane had greater TNC (220 g kg−1) than other species (≤131 g kg−1). Poor ratooning of all 12 varieties would limit their use as perennial bioenergy feedstocks in similar environments, however, breeders using germplasm selected under these conditions could ultimately enhance ratoon cold tolerance of commercial sugarcane varieties for more southerly latitudes.

This research aided in determining the impacts on rumen microbial ecology when supplemental forages and feedstuffs were added for 48 h after an initial 24-h in vitro rumen fermentation of orchardgrass (Dactylis glomerata L.) hay. Short-term shifts in bovine rumen community structure (bacteria, archea, protozoa, and fungi) resulting from each separate forage and feedstuff addition were measured using unique operational taxonomic units (OTU)s contained in terminal-restriction fragment length polymorphism (T-RFLP) profiles. The Tukey Vacuum Cleaner Analysis (TVCA) model of bacteria accounted for 66.3% of the treatment variance and OTUs clustered into 3 distinct groupings. The model developed for TVCA analysis of archaea accounted for 76.6% of the treatment variance and OTUs clustered into 2 distinct groupings. The TVCA treatment variance of protozoa accounted for 75.8% and OTUs clustered into 3 distinct groupings. Additions of various forages and feedstuffs did not result in shifts in fungal community structure in the short-term experiment. Our results demonstrate that the rumen ecology using initial T-RFLP profiles in vitro of bacteria, archaea, and protozoa and a TVCA analysis can identify pattern groupings of forages and feedstuffs. Groupings of forages and feedstuffs can help refine supplementation for improved nutritional management of ruminants.

Many cool-season grass species have evolved with asexual, nonsymptomatic fungal endophytes of the genus Epichloë (formerly Neotyphodium) of the family Clavicipitaceae. These associations range from parasitic to mutualistic and have dramatic effects on grass host chemistry, increasing resistance to abiotic (drought, soil mineral imbalance) and biotic (vertebrate and invertebrate herbivory, nematodes, plant pathogens, plant competition) stresses. Native endophyte strains produce a range of bioprotective alkaloid and other nonalkaloid secondary compounds, several of them known to have detrimental effects on grazing animals. In the past two decades, epichloid endophyte strains have been selected with marginal or no capacity of producing ergot and/or lolitrem alkaloids. These novel endophyte strains have been introduced to several grass cultivars with the idea to increase grass host resistance to abiotic stresses without hindering grazing livestock, and abiotic stresses to ensure high competitive ability of symbiotic grass cultivars. In this presentation, we discuss mechanisms underlying the competitiveness of epichloid endophyte/grass associations and consequences of endophyte infection for grassland ecosystem functions.

High yielding perennial grasses could integrate bioenergy-livestock operations, thereby, offsetting diversions of cropland to lignocellulosic crops, but research is needed to determine chemical composition and digestibility of leaf and stem fractions that might affect downstream reside uses. The objective of this study was to compare feedstock quality of leaf and stem tissues of dedicated bioenergy feedstocks: giant miscanthus (Miscanthus × giganteus), giant reed (Arundo donax), and miscane (Saccharum hybrid × Miscanthus spp.) when grown with or without supplemental irrigation on an upland site. Three species were space-planted on a silt loam soil in March 2007 and harvested prior to the first freeze in plant-cane, first ratoon, and second-ratoon crops for three years. Giant miscanthus leaf tissue had greatest acid detergent lignin and cellulose, and lowest concentrations of nitrogen (N) and total nonstructural carbohydrates (TNC) in ratoon crops. Giant reed leaf tissue had greatest concentrations of in vitro digestible dry matter (IVDMD), TNC, and N (P ≤ 0.05). Conversely, miscane stem tissue had greatest concentrations of IVDMD, TNC, hemicellulose, and low dry matter and combustible energy (P ≤ 0.05). Results suggest all species’ residue has positive feedstock attributes for thermochemical bioenergy conversion, and albeit giant miscanthus has very little potential value as fodder. Miscane stem and giant reed leaf tissue have potential value as livestock feed, although giant reed is not currently recommended for planting. Further research is needed on dietary composition, acceptability, voluntary intake, and live weight gain before any of these species are recommended as livestock feed sources.

Parasitic gastro-intestinal nematodes (GIN) are a serious challenge to sustainable small ruminant health and performance on pasture. Management practices including protein supplementation can help mitigate the deleterious effects of GIN and sustain livestock performance. We postulated that a combination of protein supplementation and grazing management would suppress GIN infection and contribute to marketable lamb gain in organic and conventional production systems. Objectives were to determine if performance and GIN infection of weaned lambs on pasture were influenced by 1) protein supplementation; 2) protein supplement source that included rumen undegradable protein (RUP) with the addition of a fish oil treatment to address energy concentration in the feed supplement; and 3) protein supplementation with RUP based on body mass and grazing interval duration. We found that lambs supplemented with RUP had increased BW and PCV, and reduced FEC and FAMACHA© scores. Body weight gains increased as the corn-fishmeal supplement was increased from 1 % to 2 % BW. Parasitized lambs may have increased dietary protein requirements that can be met in part by provision of RUP in the form of fish meal. Our work demonstrates the practical success of improved animal performance with protein supplementation based on body weight, and the importance of protein supplement source. The RUP supplement, such as fish meal, appears to have significant bearing on immunological responses as inferred from observed changes in FEC associated with the target GIN, H. contortus.

High-tannin forages can be used to help mitigate the serious limitations associated with gastrointestinal nematode (GIN) infections on efficient small ruminant production. The objective of this experiment was to determine how grazing a GIN-free, established stand of a high-tannin cultivar of birdsfoot trefoil (Lotus corniculatus L.) influenced the prevention or treatment of Haemonchus contortus (Hc) infection in lambs. A birdsfoot trefoil–enriched pasture was established on an area that was previously row cropped and not grazed for at least 15 yr. Treatments included preventative (PREV) with parasite-naïve lambs transitioned onto pasture 1 wk prior to receiving an infection of 10,000 Hc larvae, therapy (THER) with parasite-naïve lambs infected with 10,000 Hc larvae 4 wk prior to the start of grazing, and control (CONT) with naïve, uninfected lambs to verify that natural infection did not occur on pasture. Each treatment group of 12 Suffolk crossbred lambs was divided into 3 replicates per treatment, and all were supplemented with a grain mix to provide 16% CP. Fecal egg count (FEC, eggs/g wet feces) in THER lambs peaked 1 wk after the start of grazing (9,404) and after 4 wk fell to 1,068, equivalent to a FEC reduction of 88.6%. Lambs in PREV had a peak FEC of 4872 at 4 wk after infection where peak FEC was 48% less in PREV than THER lambs. Lambs in CONT did not have measurable FEC for the duration of this study. Packed cell volume (PCV, %) reflected infection status of the lambs in each group, where CONT (32%) had the highest (P < 0.05) PCV followed by THER (29%) and PREV (26%). Total weight gained in CONT lambs was greatest at 5.51 kg (P < 0.01), whereas THER and PREV (2.68 and 2.97 kg, respectively) did not differ. Grazing birdsfoot trefoil–enriched pasture can have both therapeutic and preventative effects on Hc infection in lambs and can be used in a systems approach to control GIN parasites in grazing sheep.

Silvopastoral management strategies seek to expand spatial and temporal boundaries of forage production and promote ecosystem integrity through a combination of tree thinning and understory pastures. We determined the effects of water extracts of leaf litter from three species of overstory hardwood trees, yellow poplar, red maple, and white oak, on germination of common forage species: alfalfa, red and white clover, crabgrass, orchardgrass, and tall fescue without and with endophytes to increase understanding about potential interactions between silvopastures and overstory deciduous trees. Litter extracts reduced germination in red and white clover in a concentration dependent manner with greatest effects observed for poplar > maple > oak extracts. These reductions were linearly related to increasing osmolality and electrical conductivity of the leaf extracts. Modified Gompertz growth curve models, fit to data, further indicated treatment with litter extracts, especially poplar, delayed and slowed germination. Similarly, cumulative germination of a variety of grasses was inhibited by filtered 6 % (w/v) litter extracts with the effects of poplar > maple > oak. However, germination of all forages resumed after rinsing extract-treated seeds with water indicating inhibition could be due, in part, to osmotic effects of extracts or water-soluble allelopathic compounds. Final germination varied with forage species and extract type, but in most instances, did not reach the level of the control further suggesting specific ion toxicities as well. Management practices that account for the interactions between trees and forages are needed to ensure successful establishment and persistence of mixed species swards in silvopastoral systems.

In Appalachian USA, silvopasture offers promise of increased farm productivity. A synchronized, temporal understanding of open pasture (OP) and silvopasture (SP) nutritive characteristics is essential for grazing system development. We examined pasture-type nutritive-value relationships when herbage was harvested based on morphological maturity rather than calendar date. Neutral detergent fibre and acid detergent fibre (ADF and NDF) content were greater in silvopasture, while organic matter (OM) was lower (P

We evaluated forage production patterns, weight gains and blood parameters when lambs (Ovis aries) and meat-goat (Caprus hircus) kids were finished on a mixed sward of cocksfoot (Dactylis glomerata L.), red clover (Trifolium pratense L.) and white clover (Trifolium repens L.) with (SUP) and without (UNSUP) supplemental whole cottonseed (Gossypium hirsutum; WCS) in a replicated study. Botanical composition and energy/protein ratios of the sward varied with year and with time during the growing season. Swards had greater amounts of red clover relatively early and more cocksfoot later in the season. Suffolk (SX) lambs had the heaviest body weights, Katahdin (KA) lambs were intermediate, and meat-goat (GX) kids were the lightest at the end of each year. Overall body weight gain followed a trend of SX > KA > GX, and WCS supplementation increased weight gain for all animals by 18%. Only in 2008 did SUP animals have higher blood urea nitrogen levels, which may indicate less efficient use of dietary nitrogen when grazing grass–legume pastures managed for high nutritive value compared with UNSUP animals. Gossypol in WCS did not affect blood packed cell volume between SUP and UNSUP lambs and meat-goat kids. Suffolk lambs, Katahdin lambs and cross-bred Boer meat-goat kids finished on pasture with and without WCS supplementation produced desirable body weights for most ethnic markets in the USA.

Orchardgrass (L.) is a major component of many pastures in temperate North America. Early and profuse flowering in pastures is problematic, because livestock refuse to consume flowering stems, prompting many graziers to simply avoid using this species. The objective of this research was to determine the impact of reduced flowering on the quality of harvested forage under two harvest managements of orchardgrass. Six cultivars, three normal cultivars and three sparse-flowering cultivars (mean panicle density of 141 vs. 61 panicles m⁻, respectively), were evaluated in field experiments at 21 locations in North America under a 3-cut harvest management. These cultivars were also evaluated at seven locations under a 5-cut harvest management. Sparse-flowering cultivars averaged 9% greater crude protein (CP), 3% lower neutral detergent fiber (NDF), 2% greater NDF digestibility, and 2% greater in vitro dry matter digestibility (IVDMD) than normal cultivars. For the two digestibility measures, differential panicle density between the cultivar groups explained a significant portion of variability, indicating that the increase in forage quality was proportional to the decrease in panicle density below a threshold of about 50 panicles m⁻. Lastly, differences in regrowth forage quality between cultivar groups were smaller, less consistent, and of lesser statistical significance than for first harvest. While selection for sparse flowering in orchardgrass resulted in significant cause-and-effect increases in first-harvest forage quality, these effects were too small to offset the reduced forage yield associated with the sparse-flowering trait.

Winter grazing can help reduce the need for purchased feeds in livestock production systems, when finishing cattle on pasture. Our objective was to evaluate the influence of stocking density and grazing stockpiled forage on performance of yearling steers during winter. Three grasslands were winter grazed for two years: I, naturalized pastureland, and II and III, sown and managed for hay production during the growing season but grazed in winter. Two stocking densities were used: low 7.41 and high 12.35 steers ha−1. Herbage mass was estimated before and after each grazing event, and disappearance (consumption, weathering, and trampling) was the difference between both. Forage mass and residual differed by stocking density (SD), year (YR), and grazing interval (GI), and disappearance differed by YR and GI. Grass and dead constituents of botanical composition differed by YR and GI. No differences were found for legumes and forbs. CP differed by YR and GI, and NDF and ADF differed only by YR. Steer average daily gain was 0.15 kg d−1in 2011 and 0.68 kg d−1in 2012 and varied by YR and GI. Acceptable gains in 2012 may be a product of environmental conditions that influenced herbage mass and nutritive value during stockpile and animal behavior during winter.

Understanding the growth dynamics of grass–legume swards is critical as pastoral management practices are adapted to varying economic constraints and emerging environmental considerations. Efficient management must synchronize the use of accumulated herbage with the needs of grazing livestock. This must be accomplished against the dynamic background of within and among year weather patterns interacting with herbage growth and grazing animal behavior. In the Appalachian region of the eastern United States, pastures often are dominated by orchardgrass (Dactylis glomerata L.) and white clover (Trifolium repens L.). We determined botanical composition and herbage productivity of orchardgrass and white clover swards during four consecutive years when managed as a function of canopy development and regrowth interval. Productivity was influenced by defoliation practices when mixtures were managed according to canopy development. Productivity was greatest when swards were managed as hay or when clipped to a 5-cm residue each time mean canopy height reached 20 cm. White clover declined and orchardgrass increased in the sward irrespective of defoliation treatment. Botanical composition of mixtures with the erect growing orchardgrass tended to be more stable, whereas swards including the decumbent orchardgrass tended to be invaded by weeds. Some increase in productivity occurred during the first growing season when mixtures were clipped at either 2- or 4-week intervals. Regardless of defoliation practice, white clover, and in some instances orchardgrass, presence declined during two consecutive growing seasons with various other volunteer grasses and forbs contributing to productivity. Productivity and persistence of sown sward components may be less dependent on management practices than on the expression of interactions responding to within and among year weather patterns.

Management practices of summer-dormant cool-season grasses, including compatible legume species, are not well understood. In a greenhouse experiment, competitive ability of two summer-dormant (Flecha and TX06V) and a summer-active (PDF) tall fescue [Schedonorus arundinaceus (Schreb.) Dumort = Lolium arundinaceum (Schreb.) Darbysh.] was evaluated in associations with alfalfa (Medicago sativa L.) cv. Bulldog 505. Fescue cultivars were either infected with Neotyphodium coenophialum (Morgan-Jones & Gams.) Glenn, Bacon, & Hanlin comb. nov. fungal endophyte or noninfected. Monocultures and binary mixtures were exposed to a gradually imposed soil moisture deficit stress (30% soil water capacity [SWC]) from June through August or maintained at 90% SWC (control). Indices of competitive interactions (relative yield [RY], relative yield total [RYT], and aggressivity [AGR]) were calculated. The RY of summer-dormant tall fescue was less, whereas RY of summer-active tall fescue was similar to that of alfalfa. The RYT values for alfalfa-tall fescue mixtures were not different from 1 under nonlimited soil moisture, but alfalfa-Flecha mixture had RYT

Pasture managers seek to balance leaf appearance with utilization to sustain sward productivity while meeting livestock nutritional needs. Achieving this in silvopasture must account for the influence of light and defoliation on tillering. We determined tiller production, as a function of light availability and clipping height, for two forage grasses adapted to cool, humid temperate conditions of the Appalachian region of the USA. Tiller production of cocksfoot (orchard grass) (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Schreb.) was greatest in unshaded and least in shaded sites, irrespective of residual clipping height. Juvenile plants produced more than twice as many tillers as mature plants, with differences accentuated by site, reflecting a shift in reproductive and resource-use strategies. Trends in tiller production were as follows: cocksfoot > tall fescue; 10-cm > 5-cm residual clipping height; and unshaded > partially shaded > densely shaded sites. Tiller production reaches maximum earlier in the woodlot site, regardless of species or clipping height, than at the unshaded site. Plants at the wooded site extended leaves quickly, sustaining herbage production, but had less non-structural carbohydrate and fewer tillers. Cocksfoot, but not tall fescue, sustained leaf and tiller production in the shaded sites, suggesting that cocksfoot is suited for use in silvopasture in this region.

Small farms in Appalachia need management options that diversify income opportunities, are adaptable to new livestock management strategies, and help maintain environmental integrity. Plantings of temperate bamboo (Poaceae), including species native to West Virginia, were established to determine the potential nutritive value for small ruminants, such as goats (Capra hircus), at different times of the year. The bamboo species we evaluated, included several Phyllostachys spp., Semiarundiaria fastuosa and Arundinaria gigantea, were able to withstand Appalachian winter temperatures and retain some green leaves even in late winter. Although small differences were evident, the nutritive value was generally comparable among species and exhibited similar trends over the season. Total non-structural carbohydrates in bamboo leaves decreased throughout the growing season, and then remained stable or increased during winter. Conversely, crude protein was relatively low in young leaves compared to late season or over-wintered leaves. Concentrations of fiber and protein were sufficient to meet the maintenance needs of adult goats. The ability of bamboo to remain green and maintain the nutritive value throughout winter suggested that it has potential as winter forage for goats in central Appalachia. As an upright browse, bamboo may reduce the exposure of goats to gastrointestinal parasites. Perennial stands of temperate bamboo could prove to be a valuable, multiple-use crop suitable for Appalachian farm operations and easily adaptable to goat production systems.

Small Appalachian hill farms may benefit economically by expanding grazing lands into some of their under-utilized forested acreages. Our objective was to study the forage production potential of forest to silvopasture conversion. We thinned a white oak dominated mature second growth forested area establishing two orchardgrass-perennial ryegrass-white clover silvopasture replications for comparison with two nearby open pasture replications. After thinning trees, silvopastures were limed, fertilized and seeded. Sheep were fed hay and corn scattered across the area to facilitate removal of residual understory vegetation, disruption of litter layer and incorporation of applied materials into surface soil. Each area was divided into multiple paddocks and rotationally grazed by sheep. Two 1 m2 herbage mass samples were taken from each paddock prior to animal grazing. There was no significant difference in soil moisture between silvopastures and open pastures however, there was adequate rainfall to prevent drought all 3 years. The two silvopastures received 42 and 51% of total daily incident PAR compared to the open field. Total dry forage mass yield from open pasture over the 3 years averaged 11,200 kg ha−1 y−1 and from silvopasture 6,640 kg ha−1 y−1. Silvopastures, however, had a higher PAR use efficiency (PARUE) than open pasture. Hill farms could increase grazing acreages without sacrificing all benefits from trees on the landscape by converting some areas to silvopasture.

Tall fescue [ Lolium arundinaceum (Schreb.) S.J. Darbyshire] is adapted to the diverse growing conditions of humid, temperate agro-ecosystems. A mutualistic endophytic symbiont ( Neotyphodium coenophialum , [Morgan-Jones et Gams] Glenn, Bacon, and Hanlin) contributes to this resilience, but at the same time compromises grazing livestock health. Novel endophytes that do not produce ergo-alkaloids were developed to circumvent livestock health issues, but the response of novel associations to site conditions and management practices, such as partial shade and repeated defoliation, is unclear. We conducted a field experiment with tall fescue to determine if carbon isotope discrimination ( Δ ) could be used to characterize host–endophyte association responses to site and management. Plants infected with either the native or novel non-ergogenic endophyte, or that were endophyte free were clipped to typical pasture (5 cm) or silvopasture (10 cm) residual sward heights each time mean canopy height reached 20 cm. The Δ of tall fescue was inversely related to light availability. Greater variation in Δ occurred when plants were clipped to a 5 rather than a 10 cm residue height. This trend persisted throughout the growing season and was similar whether Δ was expressed relative to potential evapotranspiration (ET o ), leaf dry matter content (LDMC) or an index of herbage nutritive value (expressed as energy relative to crude protein). Host–endophyte association did not affect Δ . This might be attributable to relatively mild growing conditions occurring in the central Appalachian region of the USA, irrespective of site conditions, or the minimal cost of hosting endophyte. Carbon isotope discrimination responses for tall fescue agree with previous observations on Δ and light availability, and might be a useful means to assess silvopastoral management practices.

The movement of faecal pathogens from land to surfaceand ground-water are of great interest because of thepublic and livestock health implications. Knowledge ofcanopy structure and how it might be managed to helpmitigate nutrient and pathogen movement in pasture isneeded to create management practices that balancelivestock production with environmental benefits.An experiment was conducted using a rainfall-simulat-ing device to test whether canopy structure of speciescommon to pastures in Appalachia, USA could bemanaged to influence dispersion of faecal pathogens.Seven pots (30-cm diameter) of white clover, orchard-grass and perennial ryegrass were lined up on horizon-tal and sloping surfaces under a rainfall simulator. Thecentre pot was inoculated at the soil surface with4 · 10 10 faecal coliform bacteria (FC) just before rainfallsimulation started. The species were maintained undershort, moderate and tall canopy management treat-ments. White clover exhibited the greatest rates oflateral and vertical dispersion of FC into the canopy,especially in the short canopy management treatmentfollowing 30 min of rainfall (about 40 mm). Lowconcentrations of faecal coliform bacteria also dispersedinto the canopies of the grass species but the differencesin concentration of FC between the grass species werenot different. When the proportion of white clover in apasture is high, the canopy should be relatively taller toreduce the likelihood of infection associated with faecalcoliform-contaminated herbage.Keywords: rain splash, pathogen dispersal, manure,canopy structure, canopy management, slope

Tall fescue [ Lolium arundinaceum , Schreb., S.J. Darbysh.] productivity and persistence often benefits from association with Neotyphodium coenophialum [Morgan-Jones and Gams], Glenn, Bacon, and Hanlin) endophyte. The influence of novel, non-ergogenic endophytes on nutritive value is unclear, especially when simultaneous stresses ( e.g. , defoliation and shading) are imposed on the association. We conducted a field experiment using Jesup tall fescue that had either a native or novel non-ergogenic fungal endophyte (AR542; referred to as MaxQ™), or that was endophyte free. Dry matter production and nutritive value including crude protein (CP), non-structural carbohydrates (TNC), ergo- and loline alkaloids, and phenolics were determined for plants stockpiled or clipped repeatedly in sites differing in the amount of light. Productivity varied less among sites when plants were infected with a native endophyte compared to novel or no endophyte. The trend suggests that native endophyte contributed to resilience of the host in this experiment. Leaf dry matter content was affected by host–endophyte association interacting with light availability suggesting differences in leaf composition could occur. Herbage CP increased, whereas TNC decreased with increasing shade. The concentration of loline alkaloids, irrespective of host–endophyte association, tended to increase in leaves with decreasing light availability and could be related to the relatively greater N concentrations in shade-grown leaves. Phenolics decreased in leaves, but increased in stembases as light availability decreased. The combination of increased loline alkaloids in leaves and phenolics in stembases, suggests that shade-grown tall fescue might have some competitive advantage based on the known anti-herbivory attributes of loline alkaloids and phenolic compounds.

For the past 35 years, a significant effort was devoted to identifying the cause of tall fescue toxicosis, a symptomless infection of tall fescue (Schedonorus phoenix [Scop.] Holub, formerly Lolium arundinaceum [Schreb.] S. J. Darbyshire, and formerly Festuca arundinacea Schreb.) by a fungal endophyte Neotyphodium coenophialum Glenn, Hanlin, and Bacon. This endophyte grows intercellularly in stems and leaf sheaths of the host plant. Among the cool-season perennial forages, only tall fescue tolerated the punishing weather, inhospitable soil, and performance demands of beef operations on a consistent basis in the southeastern portion of the United States. Consequently, tall fescue became the forage grass of choice, which led eventually to its production on about 14 million hectares nationwide. Weather and soil conditions place numerous environmental- and management-induced stresses on the plant–fungus association that influence plant persistence and nutritive value, including alkaloid production. Livestock performance on endophyte-free tall fescue was shown to be superior to that obtained on endophyte-infected tall fescue, establishing the role of fungus in the syndrome. The suite of symptoms presenting in grazing cattle resembled ergotism but much of the early research did not target mycotoxins related to this malady. After discovery of the endophyte inhabiting tall fescue, research documented production of several types of ergot and other classes of alkaloids. This led, eventually, to numerous experiments designed to develop management strategies that reduced the toxic effects of host–endophyte associations on livestock health. Accumulation patterns of biologically active alkaloids and their responses to management were defined, suggesting possible ecological value of host–endophyte associations, and ultimately led to genetic approaches that minimized production of mycotoxins, while maintaining persistence and other agronomic traits of this valuable forage grass.

The partitioning and quality of aboveground biomass have important ramifications for crop management and biomass conversion. In preliminary studies, Saccharum sp. � Miscanthus sp. hybrids exhibited stubble cold tolerance in west-central Arkansas, unlike Saccharum sp. � Saccharum spontaneum hybrids. The objective was to examine foliar and stem quality of the C4 grasses Miscanthus sinensis (‘Gracillimus’), Miscanthus x giganteus (Q42641, proprietary), Panicum virgatum (‘Alamo’), and two F1 hybrids of Saccharum sp. � Miscanthus sp. (US84-1028 and US84-1058) in a field study during 2004 (plant cane) and 2005 (first

New varieties of prairiegrass (Bromus catharticus Vahl. = B. willdenowii Kunth.) exhibit improved persistence over ‘Grasslands Matua’ under USA growing conditions, but animal performance data are lacking. We evaluated performance of lambs grazing stockpiled ‘Dixon’ prairiegrass on West Virginia hill pasture in autumn. In 2006 and 2007, a three-year-old stand of Dixon was cut for hay in late July, fertilized with 56 kg/ha of N, and stockpiled for eight weeks. Three pasture replicates of stockpiled forage were grazed by ewe lambs under a putand-take grazing system for a total of 24 days (25 September to 19 October) with budgeted grazing intensities of 50% (GI50) or 75% (GI75) removal of forage mass. At the end of the grazing period, lambs were heavier (42.3 vs. 41.2 kg), and had greater average daily gain (ADG) (264 vs. 216 g/day) on the GI50 vs. GI75 treatment, respectively, but gain per ha was greater on the GI75 treatment (193 vs. 253 kg/ha). Fall grazing intensity did not affect forage mass, botanical composition, tiller density, or nutritive value of stands harvested for hay in the following May. Good forage mass production and excellent lamb gains on stockpiled prairiegrass indicate this grass deserves serious consideration for fallfinishing of lambs.

Tillage to disrupt (prune) tree roots is an intensive practice which could improve herbage productivity at the crop-tree interface by reducing competition for water. We compared tillage effects on 9- to 11-yr-old loblolly pine (Pinus taeda L.) growth and herbage yields of annual ryegrass (Lolium multiflorum Lam.) and pearl millet [Pennisetum glaucum (L.) R. Br.] on a fragipan soil in Arkansas. Alley crops were rotationally grown in a 9.7-m wide alley (main plot) between bordering trees on one of three tillage treatments: control (surface tillage), rip followed by surface tillage, and trench plus root barrier followed by surface tillage. Topsoil water in May through September, herbage mass, and nutritive value were measured for each crop for 2 or 3 yr in three subplots systematically arrayed (north, middle, and south) across the alley. Diameter at breast height (DBH, measured 1.3 m above soil surface) and height of border trees were measured annually. Trenching resulted in a more uniform distribution of topsoil water among subplots compared to the other tillage treatments. Annual ryegrass yield did not show a tillage response, but pearl millet yielded more herbage in the rip (6760 kg ha -1 in 2003) and trench (3300 kg ha -1 in 2005) than the control treatment (4990 and 1260 kg ha -1 for 2003 and 2005, respectively). Ripping and trenching significantly reduced loblolly pine DBH and height compared to the control. Similarly configured alley cropping practices probably have little potential for annual herbage production even with root pruning.

Tall fescue [ Lolium arundinaceum (Schreb.) Darbysh.] often benefits in terms of productivity and persistence when infected with Neotyphodium coenophialum ([Morgan-Jones and Gams], Glenn, Bacon, and Hanlin) endophyte, but the influence of novel non-ergogenic endophytes is unclear. We conducted a field experiment using container-grown tall fescue plants to determine how plants allocated resources when clipped repeatedly in microsites differing in the amount of available light associated with open (full sun), and partially shaded (about 20 or 40% of full sun) conditions. Plants of the same tall fescue cultivar (Jesup) were host to either a native or novel non-ergogenic fungal endophyte (MaxQ™), or were devoid of endophyte. Seedlings of plants infected with the novel endophyte had slower germination, germinated later, and allocated more photosynthate to shoots than roots, when compared to J− or J+ plants. Herbage production of undisturbed canopies was not influenced by host–endophyte association within a microsite, with more herbage produced at the open than at the heavily shaded site. Clipping plants to a 5- or a 10-cm residue height tended to accentuate differences, with diminished productivity and greater variability occurring when plants were maintained at 5 cm. This trend was supported by allometric resource allocation patterns, and in terms of vegetative propagule mass relative to the number of propagules. Tall fescue, irrespective of host–endophyte association, grown as forage in silvopastoral situations should be managed to maintain no less than a 10-cm residual plant height. Trends in photosynthate allocation and plant size might influence persistence and should be investigated for more than two growing seasons.

The relative effects of irradiance and soil water on alley-cropped herbage are poorly understood. Our objective was to determine effects of irrigation on herbage productivity when tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] was grown in two sites, a meadow and a loblolly pine (Pinus taeda L.) alley (620 trees ha−1), near Booneville, Arkansas. Three tall fescue entries were space planted in the meadow and pine alley with or without irrigation. Herbage mass and nutritive value were determined at 8-week intervals for 2 years. Mean daily PAR was 33.9 (2004) and 37.5 mol m−2 d−1 (2005) in the meadow, while the pine alley received 5.6 mol m−2 d−1 (17% of the meadow) in 2004 and 4.3 mol m−2 d−1 (11% of meadow) in 2005. Effect of tall fescue entry tended to be small relative to site and irrigation. Irrigation compensated for evapotranspiration in the meadow, but not in the pine alley when summer rainfall was about normal (2004) or low (2005). Nevertheless, site (PAR) had a greater effect on herbage specific leaf weight, leaf elongation rate, tillers plant−1, mass tiller−1, and total nonstructural carbohydrate concentration than soil water. Irrigation might have had greater impact on herbage productivity if more water had been applied or if canopy cover had been less extreme. Silvicultural practices should be imposed to improve penetration of solar irradiance to the alley crop.

Silvopastoral systems in the Appalachian region of the USA could increase the carrying capacity of livestock and contribute to a reliable supply of high-quality herbage. In 2000, 2001 and 2002, the influence of solar radiation [0·20, 0·50 or 0·80 of maximum solar radiation (MSR); treatments 20-, 50- and 80-MSR respectively] on the productivity and nutritive value of a mixture of sown grasses and legumes established under a mature stand of conifers was investigated. Yields of dry matter (DM), crude protein (CP), total non-structural carbohydrates (TNC) and total digestible nutrients (TDN) were greater for the 80-MSR treatment except in 2000 when DM yield did not differ. As a proportion of the sward, introduced species (Dactylis glomerata L., Trifolium repens L., and Lolium perenne L.) increased over time for the MSR-80 treatment, corresponding with a decrease in the proportion of bare area and of non-introduced species. CP concentration of herbage was 207 g kg⁻¹ DM or greater across treatments and years with higher concentrations on the 20- and 50-MSR treatments. Herbage from the 80-MSR treatment had a greater concentration of TNC than that of the 20- and 50-MSR treatments. Estimated concentration of TDN was similar for all treatments in 2000 and greater for the 80-MSR treatment than the other two treatments in 2001 and 2002. High CP concentrations in herbage, as a result of appropriate thinning of trees in an Appalachian silvopastoral systems, could be utilized as a protein supplement to herbage with low CP and higher fibre concentrations.

Grasslands, including managed grazinglands, represent one of the largest ecosystems on the planet. Managed grazinglands in particular tend to occupy marginal climatic and edaphic resource zones, thus exacerbating responses in net primary productivity relative to changes in system resources, including anthropogenic factors. Climate dynamism, as evident from the fossil record, appears to be a putative feature of our planet. Recent global trends in temperature and precipitation patterns seem to differ from long-term patterns and have been associated with human activities linked with increased greenhouse gas emissions; specifically CO2. Thus grasslands, with their diverse floristic components, and interaction with and dependence upon herbivores, have a remarkable ability to persist and sustain productivity in response to changing resource conditions. This resistance and resilience to change, including uncertain long-term weather conditions, establishes managed grasslands as an important means of protecting food security. We review responses of grassland communities across regions of the USA and consider the responses in productivity and system function with respect to climatic variation. Research is needed to identify plant resources and management technologies that strengthen our ability to capitalize upon physiological and anatomical features prevalent in grassland communities associated with varying growing conditions.

The primary objective of this study was to investigate the impact of observation scale on the estimation of soil thermal properties. Transients are usually filtered out and ignored when classical Fourier approaches are used to deconstruct and model temperature time series. It was hypothesized that examination of such transients may be more important in identifying and quantifying short-term perturbations in internal soil heat transfer induced by agronomic disturbances. Data-logged temperatures were collected at 10-minute intervals from thermistor probes installed at 10 and 25 cm depths in isolated areas of two grassed plots. One plot (6T) had been treated twice with 6 Mg ha −1 composted turkey litter as received. The other plot (NPK) was fertilized at the same time with NPK fertilizer. Various methods were used to analyze the series to obtain apparent soil thermal diffusivity ( D -value) at various time scales. Results supported the hypothesis that short-term differences in internal soil heat transfer between the 6T and NPK plots were more manifest and effectively captured by estimated D -values calculated from the monthly and daily partial series. The 6T plot had higher soil organic matter content than the NPK plot and had lower apparent soil thermal diffusivity. Diurnal soil temperature amplitudes, required to calculate the mean D -values from partial series, were more effectively obtained using a temperature change rate method. The more commonly used Fourier analysis tended to be effective for this purpose when the partial series reasonably presented well-defined diurnal patterns of increasing and decreasing temperatures.

Ranchers need alternative livestock feeds when herbaceous forages become limiting in summer. Our objectives were to determine: (1) leaf and stem biomass components, (2) nutritive value [in vitro dry matter digestibility (IVDMD), total nonstructural carbohydrate (TNC), N, and N digestibility] of leaves for animal browse, (3) concentration of the secondary metabolites robinin and mimosine, and (4) in vitro leaf and bark toxicity for black locust (Robinia pseudoacacia L.) and mimosa (Albizia julibrissin Durz.), respectively, pollarded at 50 cm in Arkansas, USA. Black locust exceeded mimosa for every yield component (leaf mass tree−1, leaves shoot−1, shoots tree−1, shoot mass tree−1, stem basal area, and biomass tree−1) except mass leaf−1. Projected yields were 1,900 and 1,600 kg leaves ha−1 for black locust and mimosa, respectively, assuming a population of 12,300 trees ha−1. Mimosa leaves had greater IVDMD, TNC, and N digestibility than black locust. Mimosa leaves exceeded the nutritional N requirements of growing cattle (Bos taurus L.) and goats (Capra hircus L.), but protein supplementation would be needed for growing goats grazing black locust leaves. Tissue concentrations of secondary metabolites robinin and mimosine were below detectable limits in black locust and mimosa, respectively. The extract of black locust bark, but not leaves, was toxic to bioassayed African green monkey (Cercopithecus aethiops L.) cells. Either black locust or mimosa could provide moderate quantities of high quality, rotationally grazed forage for goats during summer months when herbaceous forage may in short supply.

Increased poultry production in the Appalachian Region provides a readily available nutrient source and a means to improve soil quality. As with any applied source ofnutrients, surface and ground wa­ ter quality can be compromised if nutrient inputs exceed plant nutrient requirements. Understanding nutrient dynamics in hill-land pasture en­ ables us to develop management practices that minimize detrimental ef­ fects on water quality, and stabilize and improve the productive capacity of highly eroded soiL The objective of this research was to assess nitrate leaching under mixed swards of orchardgrass (Dactylis glomerata), white clover (Trifolium repens), and chicory (Cichorum intybus) receiv­ ing various loadings of composted turkey litter and grazed by sheep (Ovis aries). Treatments were applied in the early spring of 1997, 1999, and 2001 and consisted of P and K only; N, P and K; 3 Mg ha- 1 com­ posted turkey litter; and 6 Mg ha-( composted turkey litter. Indications were that any of the treatments supplied adequate herbage to sustain

Soil chemical and physical reactions involving phosphorus (P) must be understood to predict the risk of P being transported from agricultural land to streams and lakes. The kinetics of P sorption by an Ultisols from West Virginia, USA, receiving P from fertilizers were compared to soils amended with turkey litter. Addition of 6.6 and 13.2 Mg turkey litter ha−1 increased Bray 1P levels to about the same level as adding 53 and 115 kg P ha−1, respectively. Phosphorus binding capacity decreased to a greater extent when P was added as fertilizer as compared to turkey litter. For example, P binding maximum was 360 mg P kg−1 dry soil when soil was amended with 6.6 Mg turkey litter ha−1 as compared to 260 mg P kg−1 dry soil when amended with 53 kg P ha−1. This study demonstrates that the decrease in P‐binding capacity with increasing soil P is less when P is added as turkey litter.

Stockpiling herbage can redistribute nutrient availability and supplement quantity for livestock, depending on production objectives. Brassicas (Brassica spp.) and improved prairiegrass (Bromus catharticus Vahl.) cultivars are adapted to growing conditions occurring in the Appalachian region and provide nutritionally valuable herbage in autumn; however, highly digestible brassica herbage may require supplementation with a fibrous companion species for efficient rumen microbe function and nutrient use by grazers. A prairiegrass– brassica hybrid [B. rapa L. 3 B. rapa subsp. pekinensis (Lour.) Hanelt.] mixture and pure stands of each were established to determine productivity and nutritive value of stockpiled stands in autumn. Field plots were established in late June of 2003 and 2004, and clipping began 74 and 63 d after planting, respectively. Prairiegrass coestablished with brassica hybrid and could be harvested in the establishment year. Sown species and year interacted to influence stand composition, dry matter productivity, and nutritive value. Dry conditions occurred shortly after planting in 2003 and slowed brassica hybrid establishment and productivity. Total dry matter varied for monospecificandmixedstands ofprairiegrassandbrassica hybrid each year, as did distribution during the season. Nutritive value varied with years and met or exceeded values suggested for efficient rumen microbe function. Herbage growth continued for about 80 d after the first clip in early September for all sward types and demonstrated the compatibility of co-seeded prairiegrass and brassica hybrid as well as the suitability of the mixture to provide adequate herbage mass and nutritive value when stockpiled in autumn.

Forage chicory is a productive forage resource for eastern North America; however, many soils in the region are acidic and deficient in P and might restrict the widespread use of forage chicory. There is no published information on response of forage chicory to P, or P acquisition strategies for morphologically different chicory cultivars. The literature suggests the following null hypothesis: “specific root length (SRL) will increase with P deficiency”. We conducted controlled environment experiments using nutrient culture to determine plant mass, mineral composition, and root morphology of three forage chicory cultivars (Grasslands Puna (GP), LaCerta (LC) and Forage Feast (FF)) as a function of P supply, and test the null hypothesis with chicory. Phosphorus increased chicory growth irrespective of cultivar. Root morphology differed among cultivars independent of P supply with FF producing about twice the taproot mass of GP or LC. Root morphology was also impacted by P supply and the specific interactions between P and cultivar. Total root length and surface area of GP increased, and did not change in LC or FF under −P conditions. Thus, the null hypothesis must be rejected. Results suggest at least two different plant responses to −P conditions in chicory that seem to be attributes of specific cultivars: (a) increase in root length of the 0.28 mm root class (GP); (b) decrease in non-taproot mass density with −P and no change in root length or ratios between diameter classes (LC). The change in root length of small diameter class roots, as observed for GP, is typical of the responses to −P described in the literature. The decrease in root density seen with LC is probably an anatomical response that is not coupled with any observable morphological response. We conclude that use of the above null hypothesis as a paradigm for plant root response to P deficiency must be rejected. The routine use of specific root length as an indicator of environmentally induced changes in root system function is precluded by the presence of anatomical and physiological changes (adaptations) that have no concomitant gross morphological changes.

Large amounts of flue gas desulfurization (FGD) and fluidized bed combustion (FBC) by‐products from burning coal, consisting primarily of gypsum, are available for potential use as a soil amendment. However, information is limited on longer‐term changes in chemical and physical properties induced over time and over small depth increments of the upper soil profile after applying these amendments. This study examined longer‐term effects in an abandoned Appalachian pasture soil amended with various liming materials and coal combustion by‐products (CCBPs). Soil chemical and physical properties were investigated over time and depths. The results indicated limited dissolution and movement of the calcium (Ca) and magnesium (Mg) applied with the chemical amendments, except for Ca and Mg associated with sulfate. However, sufficient dissolution occurred to cause significant increases in exchangeable Ca and Mg and decreases in exchangeable Al that were reflected in corresponding increases in soil pH. These ...

Microsite conditions influence plant development and resource allocation of Dactylis glomerata L. (orchardgrass), a traditional pasture species with potential as an understory crop in woodlots. A field experiment was conducted to determine how open (O), shaded woodland (W) and open-to-shaded woodland transition zone (EO, EW) microsites influenced the quantity and distribution of nonstructural carbohydrate (TNC) and crude protein (CP) among plant parts of defoliated orchardgrass. Plants established in spring (SP) or late summer (LS) were clipped each time mean sward height reached 20 cm. Microsite conditions influenced nutritive value of herbage. Nutritive value was acceptable when not more than 45–50% light attenuation (as a function of shading by nearby trees) occurred relative to open pasture. Twice as much TNC accumulated in stembases of LS compared to SP plants. Concentrations of TNC were least in plants growing at W, regardless of planting time. Stembase TNC depletion occurred in SP plants, regardless of microsite, and LS plants growing at W. CP concentrations were greater in herbage from W compared to O sites, suggesting the N needs of the plant were met with minimal fertilizer N inputs. The ratio of C:N and thus herbage energy expressed as total digestible nutrients (TDN), relative to CP declined as shade increased. Increased protein content is offset by lower fiber, lower nonstructural carbohydrate and the possibility of reduced preference by grazers. Nutritive value is improved by modest amounts of shade relative to plants growing in full sunlight, and allowing cool temperate origin grasses to vernalize is beneficial in terms of productivity, nutritive value, and persistence.

Botanical composition of pasture in much of the Appalachian Region varies as weather patterns interacting with abiotic and biotic factors create conditions allowing a range of plant species to occupy temporal and spatial gaps in the stand. Field-grown old world bluestem [Bothriochloa caucasia (Trin.) C.E. Hubb.] or perennial ryegrass (Lolium perenne L.) were defoliated at fixed time intervals (1-, 2-, or 4-wk for old world bluestem and 2-, 4-, or 6-wk intervals for perennial ryegrass). Herbage mass, sward botanical composition, and estimates of nutritive value were determined. White clover (Trifolium repens L.), black medic (Medicago lupulina L), and various common forbs and grasses volunteered in all stands. Old world bluestem yields ranged from 3.38 Mg ha 21 (1-wk regrowth interval in 2002) to 9.42 Mg ha 21 (4-wk regrowth interval in 2000). Perennial ryegrass yield increased with increasing regrowth interval in 2002, ranging from 3.16 to 7.29 Mg ha 21 . The longest regrowth interval did not necessarily lead to the greatest productivity. Old world bluestem swards clipped at 4-wk intervals decreased 60% by the third growing season, whereas perennial ryegrass swards clipped at 6-wk intervals increased by 37%. The proportion of encroaching species increased substantially in perennial ryegrass but not old world bluestem swards by 2002, suggesting that combined effects of repeated defoliation and weather influenced sward composition and productivity. Choice of plant resource, timing and intensity of defoliation, and very likely nutrient inputs coinciding with requirements of sown species could influence sward composition and help manage diversity to sustain productivity.

Neotyphodium spp. fungal endophytes form symbiotic associations with agronomic grasses with expression ranging from mutualistic to parasitic. In general, endophyte infection frequencies seem more variable in natural compared to pastoral situations, suggesting that expression and benefits attributable to endophyte infection depend on the resource environment in which the host‐endophyte complex was formed and the conditions under which it is being grown. Emerging evidence suggests that expression is not always mutualistic or beneficial to the host in terms of productivity and persistence in resource-limited environments. Expression of host‐ endophyte associations will vary depending on resource availability and environmental conditions that influence host physiology and growth, and herbivore behavior. New research suggest alkaloids and secondary metabolites produced by host‐ endophyte associations can have physiological functions in addition to acting as herbivore deterrents. Novel host‐endophyte associations are being created that maintain insect and disease resistance, while having minimal detrimental impact on mammalian herbivores. The influence of host‐endophyte associations on sward composition and soil food webs is only now coming to light. While novel endophyte associations and their attendant mechanisms can be considered beneficial in some respect, the associations may not be as adaptable to stressful or marginal resource environments and could have long-term ecological impacts measured in terms of persistence and total productivity of the sward. We review the extensive published work on host‐endophyte interactions and illustrate the complexity of host‐ endophyte associations and their interactions with environment, and the range of responses that occur.

The forage potential of chicory (Cichorium intybus L.) has not been realized in southern West Virginia (WV) because ruminants are reluctant to consume the herbage. Chicory contains bitter sesquiterpene lactones that can adversely impact palatability. This study was undertaken to determine whether sesquiterpene lactone concentrations in chicory grown in southern WV differ from those in chicory grown in central Pennsylvania (PA) where chicory is grazed readily. Herbage was collected in 1997 and 1998 from cultivars Grasslands Puna (Puna), INIA le Lacerta (Lacerta), and Forage Feast established at research sites near State College, PA, and Beckley, WV. The total concentration of sesquiterpene lactones in WV-grown cultivars was 0.58% (dry matter basis) in Puna, 0.59% in Lacerta, and 0.79% in Forage Feast in 1997 and ranged from 1.03 (Lacerta) to 1.52% (Forage Feast) in 1998. In PA-grown cultivars, sesquiterpene lactones represented 0.16 (Puna), 0.18 (Lacerta), and 0.27% (Forage Feast) of the forage dry matter in 1997 and ranged from 0.32 (Lacerta) to 0.55% (Forage Feast) in 1998. Concentrations of lactucin, lactucopicrin, and total sesquiterpene lactones in Forage Feast exceeded those in the other cultivars grown at the same site. The lowest concentrations of lactucopicrin and total sesquiterpene lactones observed among WV-grown cultivars were higher (2-fold or more) than the highest concentrations present in cultivars grown the same year in PA. Mineral analyses of soils from the two cultivation sites indicate that P availability may influence sesquiterpene lactone composition of chicory herbage. Results provide a foundation for future studies of environmental effects on sesquiterpene lactone composition and palatability of chicory herbage.

Stockpiling herbage helps redistribute nutrient availability and supplements quantity to sustain or finish livestock, depending on production objectives. In the Appalachian region of the USA, autumn stockpiled herbage is harvested, with little expectation for useable regrowth. spp. and prairiegrass (Vahl.) grow vigorously in autumn and tolerate defoliation providing a means to extend productivity in autumn. Mixed stands of prairiegrass and a brassica hybrid were established in late June of 2003 and 2004, with clipping begun in mid-September to determine production and nutritive value of regrowth herbage. Stockpiled prairiegrass-brassica hybrid stands tolerated repeated clipping, but stockpiled yield and the number of regrowth harvests decreased with increased duration of the stockpile interval, and no regrowth harvests were obtained when the stands were stockpiled until mid-November (130 days after planting). Regrowth accounted for as much as 35% of total yield in autumn when stockpiled harvests were made prior to late October (about 115 days after planting). Nutritive value expressed in terms of nonstructural carbohydrates, crude protein, and total digestible nutrients varied depending on year, but decreased with successive clippings or increased stockpiling duration. Herbage and nutrient yield of a prairiegrass-brassica hybrid mixed stand declined substantially after mid-October, in part, reflecting a shift in growth from leaf to tuber in the brassica component of the stand. Stockpiling stands of prairiegrass-brassica hybrid beyond mid-October essentially eliminates any meaningful regrowth production. Regrowth from stands clipped prior to mid-October extends the duration of growth of the mixture and makes a modest contribution to total herbage production in autumn.

Microsite influences development and resource allocation of Dactylis glomerata L. (orchardgrass), a traditional pasture species with potential as an understory crop in silvopasture of humid temperate regions. An experiment using container-grown orchardgrass was conducted under field conditions to determine how open (O), shaded woodland (W) and open-to-shaded woodland transition zone (EO, EW) microsites influenced leaf DM production. Plants established in spring (SP) and late summer (LS) were clipped each time mean canopy height reached 20 cm. Dry matter production and allocation among structures differed, as a function of light attenuation. Specific leaf area (SLA) and photosynthetic nitrogen-use efficiency (PNUE) were associated with leaf DM production, whereas leaf N, net assimilation rate and shoot total nonstructural carbohydrates (TNC), were not. Specific leaf area was related to leaf DM of LS plants, whereas PNUE influenced leaf DM of SP plants. Stembase TNC was inversely related to relative regrowth rate (RGRR) with RGRR greatest and TNC the least at W. The relationship for RGRR and TNC for SP plants growing at O and LS plants growing at W was similar. Regardless of how indices of growth are related, SP and LS plantings responded as separate populations (representing young and established plants respectively) that have different leaf DM production efficiencies. Orchardgrass was able to sustain leaf production when subjected to simultaneous stresses of shade and repeated defoliation. The LS plants growing at W respond in a manner similar to SP plants and may require management practices attuned to establishing or immature plants.

Microsite influences on resource allocation related to silvopastoral swards undergoing repeated defoliation are unclear. Defoliating traditional pasture species according to canopy development criteria may not be appropriate when the plants grow as understory crops in woodlots. An experiment using container-grown plants was conducted under field conditions to determine how open (O), shaded woodland (W) and open-to-shaded woodland transition zones (E O, E W), representing the partial shade conditions found in silvopastoral settings, influenced productivity and dry matter allocation in Dactylis glomerata L. Plants established in spring (SP) and late summer (LS) were clipped each time mean sward height reached 20 cm. Dry matter production differed for SP and LS plantings, and was greater in O than W sites. Dry matter allocation to shoots of SP plants indicated some agronomic benefit associated with the E O and E W sites. Leaf mass did not vary with irradiance, but stembase mass did. The SP plants had numerous small tillers whereas LS plants were composed of comparatively fewer but more massive tillers. Plants growing at O, E O and E W were similar, whereas plants in the W site were smaller and had the fewest tillers regardless of planting time. Results suggest that defoliation management for shaded components of silvopastoral systems should be based on some index other than sward height, and that management criteria might change during the growing season. Less intensive removal (e.g., 10-cm rather that 5-cm residue) should be considered for defoliated, shade grown plants, since this could allow more stembase and nonstructural carbohydrate storage tissues to remain.

The Appalachian region is characterized by hilly topography and a humid temperate climate. In most areas agriculture is limited to pasture although the native climax vegetation is a species-diverse forest. Silvopasture systems can help diversify and increase farm income. Information is needed on the yield response of forage grown as an understory crop among trees. The light environment of a conifer silvopasture was characterized by three methods, a hand-held photosynthetically active radiation (PAR) meter for quick measurements over a large area, fixed PAR meters recorded using data loggers for a large number of measurements over time, and hemispherical photography with software to calculate seasonal direct beam radiation. Light data were considered in terms of forage yield. Plots were harvested when forage reached 20–25 cm in height after which the entire area was grazed by sheep. There were limitations to all methods of quantifying radiation environment for predicting yield. Yield decreased linearly with decreased PAR; however, data variability was high and correlations, while statistically significant, were weak. Grazed silvopastures are dynamic with shifting yield patterns in response to the interactions between the spatially variable soil, changing seasonal environment, and spatially variable animal impacts for each grazing event.