Arrhenatherum Elatius Research Articles

Leaf and Root Turnover of Three Ecologically Contrasting Grass Species in Relation to Their Performance along a Productivity Gradient

We tested the hypothesis that species characteristic of nutrient rich sites always grow faster than species from nutrient poor sites, but have a shorter organ life span. It has been suggested that this fast tissue turnover may limit their performance at nutrient poor sites. Three ecologically contrasting grasses were studied: Bromus erectus, characteristic of nutrient poor meadows, and Arrhenatherum elatius and Dactylis glomerata, characteristic of more nutrient rich grasslands. These species were grown at three meadows differing in nutrient availability and harvested 3, 7, 9.5 and 11 months after germination. D. glomerata produced at all sites the largest total biomass. B. erectus showed the lowest growth response to site conditions. D. glomerata and A. elatius had a faster leaf turnover than B. erectus. D. glomerata had a faster root turnover than B. erectus. Root turnover of A. elatius was probably also faster than that of B. erectus, but this was partially obscured by decomposition of dead roots. D. glomerata and A. elatius had a lower tissue density of leaves and roots than B. erectus. We conclude that there is a negative correlation between the plant's ability to increase its growth with increasing nutrient availability and the tissue life span. Nutrient losses due to fast tissue turnover may prevent the dominance of fast-growing species at nutrient poor sites, although these species are in general better at nutrient acquisition. The negative correlation between growth rate and tissue longevity is to a large extent a result of constraints caused by plant tissue structure.

Pasture legumes for the drought-prone, outwash soils of the southern Mackenzie Basin

The persistence of lucerne (Medicugo sativa L.), red clover (Trifofiumpratense L.), birdsfoot trefoil (Lotus cornicufatus L.) and perennial lupin (Lupinuspolyphyks Lindley), overdrilled with and without companion grasses, was compared at a site representative of dry, acidic, outwash soils in the southern Mackenzie Basin, South Island. Plant populations were monitored for 9 years and legume seedling regeneration and stand recruitment were examined over three consecutive years under grazing by sheep and cattle. Pcrcnnial lupin was the best adapted legume species. Stand density increased by re-seeding. In contrast, few seedlings of birdsfoot trefoil developed as a result of reseeding, and survival of birdsfoot trefoil was generally restricted to the more favourable areas of the mosaic of soil. Red clover did not persist, and the few plants of lucerne that survived lacked vigour. Tall oat grass and cocksfoot showed good vigour and persistence across the mosaic of soil; smooth brome performed well and spread within the more favourable areas. From these results, _p_erennial.lupin,-tall-oat-grass-and-cocksfoot~a~~ to be the best species available for the future development of sustainable pastoral systems in drought-prone outwash landscapes in the Mackenzie Basin. Keywords: dryland, establishment, Lotus corniculatus, Lupinus po&phyflus, outwash soils, pasture legumes, persistence, seedling recruitment

Temporal and Nutritional Influences on the Response to Elevated CO2 in Selected British Grasses

To investigate the duration of the CO2 response and its interaction with mineral nutrition, CO2-enrichment experiments were performed on four British grasses of differing ecology and functional type: Arrhenatherum elatius (L.) Beauv., Festuca ovina L., Festuca rubra L. and Poa annua L. Naturally-lit, glasshouse cabinets were used, with a non-limiting water supply and a daytime mean temperature of 18 °C. Two CO2 treatments were maintained at nominal concentrations of 350 and 700 vpm and were combined factorially with two levels of balanced mineral nutrition at conductivities of 0·1 and 1 mS cm-1. Harvests took place at planting-out, and at 16, 37 and 58 d thereafter.Fitted curves were used to derive instantaneous values of total dry weight, relative growth rate (RGR), shoot weight fraction (SWF) and unit shoot rate (USR) for all combinations of species, CO2 level, nutrient level and time of harvesting.At the higher nutrient level there was a reasonably close agreement with previous estimates of the CO2 response in the four species. The response, if any, most often arose from an increase in USR being accompanied by a less than proportionate decline in SWF. Responses were sustained throughout the period studied. At the lower nutrient level, all species showed a CO2 response initially, but this declined at a rate which was inversely related to the CO2-responsiveness of the species at the higher nutrient level.The underlying ontogenetic drift appeared to be markedly towards adjustment in SWF and away from that of USR. However, this drift was retarded, suspended or even reversed by low-nutrient conditions and/or by high CO2 responsiveness in the species itself.

A comparative study of growth strategies in two varieties of Arrhenatherum elatius

Growth strategies of the two varieties of Arrhenatherum elatius were studied. The two varieties studied were: onion couch, which produces bulbous swollen internodes and is an arable weed of local importance, whilst tall oat-grass is more widely distributed. An experiment in which the two varieties were grown at different densities in monoculture and were harvested at intervals, highlighted various aspects of the competitive relation between the two varieties and an annual crop. Significant and consistent differences were found between the two varieties for most of the attributes measured during the two growing seasons. Tall oat-grass allocated a greater proportion of its whole shoot dry weight to producing vigorous aerial tillers, whereas onion couch allocated a greater proportion of its whole shoot dry weight to the development of basal internodes. The regulation of tiller number as a reaction to increasing density in tall oat-grass is achieved by high tiller mortality, whereas in onion couch, this stress is expressed by small tiller mortality. Growth pattern shown by the two varieties of A. elatius reflect the adaptive strategies evolved by them in two different habitats and are due to the genetic factors which determine the presence or absence of their characteristic basal internodes.

Arrhenatherum elatius (L.) Beauv. - a review, and evaluation of tall oat grass for dryland and hawkweed-affected country in the South Island

Tall oat grass has a long history in New Zealand agriculture. Reference was made to it in the 1880s as a useful grass and it was included in many trials such as those of Macpherson, Cockayne, Calder, Dunbar, Sievwright, Moore and others. While the survival and performance of tall oat grass was generally reported as being good, observations on palatability were mixed. The growth pattern was typically noted as being one of early spring growth, rapidly changing to reproductive form thereafter with a consequent decrease in acceptability to stock. In 1988, new accessions of tall oat grass originating from diverse countries were introduced to New Zealand from the US Department of Agriculture. This paper describes the physical characteristics of tall oat grass and field performance at Galloway Station, a site badly affected by hawkweed, and on other farms. This grass appears best suited to moderate-low rainfall areas (400-700 mm p.a.) which are not too exposed or too cold and it shows good potential for survival and spread in the drier soil conditions which result from hawkweed invasion in mid-altitude grassland areas. Two accessions, one from Chile and the other from Switzerland, have been identified which have superior winter performance, rust resistance and are less prone to bolting into a reproductive phase in the spring. These, along with a preliminary selection containing a wider genetic base, are being commercially evaluated at present. Keywords: Arrhenatherum elatius, tall oat grass, hawkweeds, plant selection, vegetation

More persistent legumes and grasses for oversown tussock country

A grazing trial on oversown tussock country at Tara Hills Research Station, started in 1978 and still continuing, has highlighted short comings of clovers and grasses traditionally used for improvement. In 1984 a wide range of legume and grass germplasm was planted into each of the nine stocking rate/management treatments to identify plant material more persistent than that traditionally used, and investigate specific responses under Extreme (high stocking rate), Optimal (moderate stocking rate and management giving optimum liveweight gain/ha) and Las (low stocking rate) grazing management. After 6 years none of the 12 white clover, 7 alsike and 9 lotus lines tested persisted significantly better than Grasslands Huia white clover (Trifolium repens). Plant survival and spread of Caucasian clover (Trifolium ambiguum) was exceptional. In terms of persistence and spread this legume ranked first out of the 56 germplasm lines under examination. The 15 ryegrasses examined did not persist better than Grasslands Nui ryegrass (Lolium perenne). However, for Optimal management, many ryegrasses performed better than Nui. Cocksfoot(Dactylis glomerata) also performed very well, with Grasslands Wana showing greater persistence under Extreme management than other cocksfoots and ryegrasses. Tall oat grass (Arrhenatherum elatius) was very persistent and like Caucasian clover performed well under all managements. Other grasses tested showed poor persistence, as did the herb sheep's burnet (Sanguisorba minor). Keywords: Arrhenatherum elatius, Dactylis glomerata, grazing management, high country persistence, sustainable improvement, Trifolium ambiguum, tussock grasslands

Ustilago segetum var. avenae . [Distribution map

Abstract A new distribution map is provided for Ustilago segetum (Bull.) Roussel var. avenae (Pers.) Brun. Hosts: Oats ( Avena sativa and oat grass ( Arrhenatherum elatius ). Information is given on the geographical distribution in Africa, Angola, Egypt, Ethiopia, Kenya, Libya, Madagascar, Morocco, South Africa, Tanzania, Tunisia, Zambia, Zimbabwe, Asia, Azerbaijan, Afghanistan, Burma, China, Gansu, Hebei, Heilongjiang, Henan, Jiangsu, Jilin, Liaoning, Shanxi, Shaanxi, Sichuan, Zhejiang, Georgia, India, Bihar, Uttar Pradesh, New Delhi, Himachal Pradesh, Iran, Iraq, Israel, Japan, Kazakhstan, Kirgistan, Korea, Lebanon, Mongolia, Pakistan, Philippines, Russia, European region, Azov-Black sea, Caucasus, Caucasus region, Central Asia, Siberia, Far East, Sri Lanka, Taiwan, Turkestan, Turkey, Australasia & Oceania, Australia, New South Wales, Queensland, South Australia, Victoria, Western Australia, Tasmania, Hawaii, New Zealand, Papua New Guinea, Europe, Austria, Bulgaria, Cyprus, Czechoslovakia, Denmark, Estonia, Finland, France, Corsica, Germany, Greece, Crete, Hungary, Italy, Irish Republic, Latvia, Lithuania, Netherlands, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland, UK, England, Scotland, Wales, Northetn Ireland, Yugoslavia, North America, Bermuda, Canada, British Columbia, Alberta, Manitoba, New Brunswick, Nfld, Ontario, Prince Edward Island, Nova Scotia, Saskatchewan, Mexico, USA, Alaska, Alabama, Arkansas, California, Colorado, Florida, Georgia, Hawaii, Iowa, Massachussetts, Minnesota, Mississippi, New Jersey, New Mexico, North Carolina, Oklahoma, Oregon, South Carolina, South Dakota, Texas, Virginia, Wyoming, Idaho, New York, Pennsylvania, Central America & West Indies, Guatemala, Puerto Rico, South America, Argentina, Brazil, Rio Grande do Sul, Chile, Colombia, Peru, Uruguay, Venezuela.

GROUND COVERS FOR SEMI-ARID LANDSCAPES.

The High Plains of Texas is a short-grass prairie with an extremely stressful environment which limits adapted ornamentals. Plant materials capable of consistent performance have yet to be established for this region. Twelve perennial ground covers were evaluated for urban landscape use. Species were planted in a completely radomized design split in time with four replicates. Ground coverage and distance of spread were evaluated monthly for two growing seasons in 1989 and 1990. Visual ratings of quality as ground cover were also determined using color, growth and density as indices. Sedum brevifolium, Sedum acre, Lysimachia nummularia, Sedum sieboldi, and Arrhenatherum elatius `Variegatum' were the most promising species for all criteria. Sedum acre and Arrhenatherum elatius `Variegatum' did not perform well at temperatures above 40°C. Sedum stolonifera failed to survive in this demanding environment.

Plant distribution patterns during early succession on an artificial protosoil

Abstract. Plant succession has been studied since 1977 in permanent plots on a calcareous protosoil in the northern outskirts of Göttingen (Central Germany). At the beginning the substrate was extremely poor in organic carbon and nitrogen. On 128 plots of 100 m2, the temporal and spatial distribution of the most conspicuous plant species showed remarkable changes and correlations to soil site factors. While presenting data on Melilotus alba, Medicago lupulina, Agropyron repens, Arrhenatherum elatius, Dactylis glomerata, and Picris hieracioides the mechanisms of successional changes on nutrient‐poor soils are discussed. It is demonstrated that a high cover of legumes favours the accumulation of soil nitrogen. Grassland species were more abundant in areas with low humus content whereas ruderal plant species preferred those parts of the area which contained more humus in the substrate. Life‐form, colonization and population strategies play an important role in the described successional processes, in addition to resource competition. Finally, some methodological conclusions for permanent plot studies are presented.

A Comparative Study of the Growth and Morphology of Eight Grass Species from Habitats with Different Nutrient Availabilities

1. To find out which properties enable plant species to dominate in nutrient-poor habitats and which properties benefit species in nutrient-rich habitats, we studied the growth and morphology of eight perennial grass species from habitats with contrasting soil fertilities in a pot experiment under controlled conditions in a glasshouse. 2. The species were grown under nutrient-poor and nutrient-rich conditions. Ranked from the least responsive to the most responsive to the supply of nutrients they were: Festuca ovina, F. rubra, Anthoxanthum odoratum, F. arundinacea, Alopecurus pratensis, F. pratensis, Arrhenatherum elatius, Lolium perenne. 3. The response correlated positively with the Ellenberg nitrogen number of the species. No differences in initial relative growth rate were found between the species, but after 4 weeks the plant dry weight increased with increasing nitrogen number as a result of variation in embryo plus endosperm weight. 4. Species characteristic of nutrient-rich hayfields are taller and show a more homogeneous vertical distribution of photosynthetic area than the species from nutrient-poor habitats, which have most of their leaf area below 15 cm. Species from the nutrient-poor habitats allocated less dry matter to the roots and consequently more to the shoot, than species from nutrient-rich conditions. However, leaf and root morphology seem to be most clearly adapted to the habitat. 5. Species from nutrient-rich habitats have a higher specific leaf area (SLA) than species from nutrient-poor habitats, while species from nutrient-poor habitats had more root length per unit root weight (SRL) than species from nutrient-rich habitats.

Shoot Thrust and Its Role in Plant Competition

1. The generation of shoot thrust was measured in eight contrasted herbaceous species (Arrhenatherum elatius, Bromus erectus, Campanula rotundifolia, Cerastium fontanum, Hypericum perforatum, Koeleria macrantha, Poa trivialis and Urtica dioica) using a framework of weighted windows that could be opened by an expanding shoot. 2. The species that occur as vegetation dominants in their usual habitats (A. elatius, B. erectus and U. dioica) were found to have the greatest ability to generate thrust

An Experimental Test of Plant Strategy Theory

Two of the central hypotheses of the triangular model of primary plant strategies were tested by a movel technique involving seven grasses of contrasted ecology grown in pure stands and an additive mixture on an experimental matrix of crossed gradients of mineral nutrient stress and vegetation disturbance. The experimental design allowed reductions in vegetative and reproductive vigor resulting from interspecific competition to be distinguished from those arising from direct effects of nutrient stress and vegetation disturbance. It was also possible to determine the extent to which competitive suppression of each species was affected by stress and disturbance. In isolation, all species showed maximum vegetative and reproductive vigor at high soil fertility and low disturbance. In the mixture, absolute reductions in biomass and flowering due to competition were greatest at high soil fertility and low disturbance, and the species of most extreme strategy became restricted to areas of the matrix broadly consistent with those predicted by strategy classification. When standardized for differences in biomass in pure stands, the effect of competition remained relatively constant across the stress—disturbance matrix for all species except Poa annua, which was less restricted by competition at high intensities of stress. There were marked and consistent differences between species in their susceptibility to competition. At both high and low soil fertility, two species of natural occurrence on infertile soils (Festuca ovina, Bromus erectus) were poor competitors relative to Arrhenatherum elatius, a widespread dominant of productive grasslands. The effect of competition was least severe on flowering of annuals in low—stress portions of the matrix. If competition is assessed simply as the percentage of reduction in biomass between pure and mixed stands it appears that competition intensity is constant across different intensities of stress and disturbances. However, observations that maximum reductions in biomass coincided with low stress and low disturbance, that competition decreased in importance as a factor reducing yield and flowering (relative to stress and disturbance) as stress and disturbance intensities increased, and that there was a consistently inferior competitive ability of plants from infertile soils at all positions on the matrix all support the hypothesis that competition declines in importance as a vegetation determinant in the vegetation of infertile soils.

Agro‐ecology of onion couch (Arrhenathemm elatius var. bulbosum).

SUMMARYThe agro‐ecology of onion couch (Arrhenatherum elatius var. bulbosum), a well known weed of arable land is studied. Contribution of seeds from onion couch and a more widespread variety of Arrhenatherum elatius: tall oat‐grass, towards future ingress of onion couch in arable fields has indicated that the tall oat‐grass variety is not a potential weed of arable land. It appears that vegetative propagules rather than the seeds are the effective means of propagation of the onion couch variety in arable fields. An experiment performed to test any modifying effect of the soil texture indicated that onion couch is restricted to loamy soils and there is a complete absence from heavy clays and sandy soils. This could be due to the moist and protective micro‐environment provided by the texture of the soils to partially buried vegetative propagules of onion couch, which are susceptible to drought.

Agro‐ecology of onion couch (Arrhenathemm elatius var. bulbosum (Willd.)).

SUMMARYThis study investigates the performance of vegetative propagules of onion couch (Arrhenatherum elatius var. bulbosum) of varying sizes during the crop growth cycle; especially trends in tiller and bulb production and crop yield loss. The results suggest that the earlier the crop canopy closes the more suppression it will exert on the bulb formation stage of onion couch and hence its future reproductive potential. The closed canopy provided by a dense crop cut short the bulb formation phase and forced onion couch to invest more in aerial tillers in order to compete and coexist with the taller tillers of the crop. An additive experimental design used here to predict the crop losses indicated that natural infestation of onion couch caused greater crop yield loss compared to artificially planted plots. It was found that, although the regrowth from large aggregates with densely packed bulb chains is reduced by correlative dominance and density dependent mortality, presence of such large aggregates can affect crop yield by interfering with the establishment of crop. The competitiveness and development pattern of onion couch suggests that the recent spread of the weed and the reported variable results of control measures is due to the recent shift in agricultural practices.

Interference between sown grasses and the growth of rhizome of Elymus repens (couch grass)

Rhizome growth of Elymus repens (L.) Gould (couch grass) from single-node fragments on plots sown with six perennial grasses in a surrounding hexagonal mosaic was reduced by a factor of 10, compared with initially bare plots. The location of shoot complexes of E. repens after three seasons indicated that Arrhenatherum elatius and, to lesser extents, Agrostis stolonifera or Dactylis glomerata, prevented couch growth more than Holcus lanatus or Poa trivialis. Strips of sown grass at the edge of arable fields may therefore reduce the spread of couch grass into adjacent crops. Fertiliser application of 32 kg N ha −1 doubled the amount of couch rhizome. Mefluidide and paclobutrazol, plant growth regulators which might be used to manage sown grass, had minor effects on rhizome structure. D. glomerata did not spread from where it was sown and was largely uninvaded by other species.

Response of Yellow Starthistle (Centaurea solstitialis) and Grass Biomass to Grass, Picloram, and Fertilizer Combinations

A 2-yr study was conducted to evaluate the response of yellow starthistle density and grass biomass to combinations of newly seeded grass, picloram, and fertilizer. A combination of ‘Tualatin’ tall oatgrass or ‘Paiute’ orchardgrass with 0.14 or 0.28 kg ae/ha of picloram effectively controlled yellow starthistle and improved forage production. Grass seeded alone or combined with fertilizer neither controlled yellow starthistle nor improved forage production. Three-way combinations of grass, picloram, and fertilizer did not affect yellow starthistle density in either year but resulted in more ‘Tualatin’ tall oatgrass biomass in 1987.

A comparative study of plant responsiveness to the duration of episodes of mineral nutrient enrichment

summaryGrowth, dry matter partitioning and nitrogen capture were compared in two grasses of contrasted ecology, subjected to treatments involving pulses of nutrient enrichment of various durations supplied every 6 d over a period of 6 weeks. The potentially fast‐growing Arrhenatherum elatius ssp. bulbosum (Willd.) Schubler and Martens was superior in rates of nitrogen capture and dry matter production when exposed to long (≥ 10 h) nutrient pulses whereas the slow‐growing species Festuca ovina L. enjoyed an advantage in treatments providing nutrient pulses of between 0.1 and 10 h duration. These results are consistent with differences in mechanisms of resource foraging predicted by the C‐S‐R model of plant strategies and related models. It is concluded that the lower rates of turnover of tissues and the capacity of roots to remain viable under chronic nutrient stress are important components of the ability of Festuca ovina to exploit brief pulses of mineral nutrient enrichment. The range in duration of the pulses advantageous to F. ovina corresponds to that which might be expected to arise from the death and recovery of microbial populations in infertile soils.

Management of Roadside Vegetation: The Long-Term Effects of Cutting

SUMMARY (1) An experimental comparison of the effects of eleven cutting treatments on roadside vegetation was made at two sites in Cambridgeshire over a period of 18 years. The treatments were combinations of cutting date, cutting frequency (0, 1, 2, or 5 times per annum) cutting machine (haymower, flail mower or rotary mower) and leaving or removing cuttings. (2) Vascular plant species-richness of the vegetation was unaffected by altering the date of a single cut from June to July or by cutting with different types of machine. It was lowest in the uncut plots and highest in plots cut twice per annum. (3) Increased cutting frequency significantly decreased the frequency of ten mainly coarse growing species, including Elymus repens, Arrhenatherum elatius and Anthriscus sylvestris. Eleven finer species (mostly grasses) increased in frequency and two others (Ranunculus repens and Plantago lanceolata) reached a maximum at two cuts per annum. (4) Removing cuttings led to an increase in plant species-richness, mainly due to an increase in herbs. Removing cuttings led to a decrease in extractable potassium in the soil but most other soil nutrients, including total and available nitrogen, were unaffected. It is suggested that the increase in species-richness was not due to reduced levels of soil nutrients, but was probably associated with the disturbance and scarification which accompanied the removal of cuttings by hand raking, and with the alleviation of the smothering effect caused by leaving cut vegetation on the verges. (5) The effects of the treatments on species-richness and the frequencies of individual species were very similar at both sites.

Interference between Hieracium pilosella and Arrhenatherum elatius in colliery spoils of north of France : Allelopathy or competition?

On colliery heaps in northern France, a tall grassland community dominated by Arrhenatherum elatius, give place to a thin grassland community in which Hieracium pilosella is very abundant. It has been claimed that Hieracium pilosella is an allelopathic species and this phenomenon has been investigated as an explanation of this phase of plant succession. The importance of osmotic pressure in tested plant extracts is demonstrated and may be responsible for presumed allelopathy. Two phytotoxic compounds have been revealed in roots+rhizomes of Hieracium pilosella (umbelliferon and apigenin-glucoside). A third phytotoxic compound was exuded by roots in hydroponic cultures (7-glucoside-umbelliferon or skimin). However no toxicity of soil has been found and no phytotoxic compounds appeared to be present in the soil under Hieracium pilosella. Experimental mixed cultures (sterile or non-sterile conditions) reveal suppression of Hieracium pilosella by Arrhenatherum elatius rather than the reverse. Allelopathy cannot be invoked to explain this plant succession.

Notas agrostológicas sobre la flora balear

Se estudia el material original del herbario de H. Knoche para discutir la corología de algunas especies de gramíneas de la tribu Aveneae. Se citan tres nuevos táxones para las Islas Baleares: Avena sterilis L. var. maxima Pérez Lara, Arrhenatherum elatius subsp. baeticum Romero Zarco y A. Album (Vahl) W.D. Clayton var. album.