A key to identify perennial grasses in central Argentina based on microhistological characteristics

1998 ◽  
Vol 76 (8) ◽  
pp. 1467-1475 ◽  
Author(s):  
Lilia I Lindström ◽  
María B Mújica ◽  
Roberto M Bóo

The most important economic activity on the Caldenal rangelands in central Argentina is cattle raising in cow-calf operations. It is known that grasses are the bulk of the diets and a previous study provided detailed information on the epidermal structures of the most important grass species in the region. The objective of this work was the elaboration of a key to facilitate the microhistological analysis of esophageal, fecal, and ruminal samples. The key allows for the identification of eleven perennial grass species from epidermal characteristics of the blades, sheaths, and stems. The most important epidermal characteristics relevant to microhistological identification are illustrated for each species.Key words: leaf and stem epidermis, Gramineae, microhistological key, perennial grasses, Caldenal.

2016 ◽  
Vol 16 ◽  
pp. 275-279
Author(s):  
E.J. Hall ◽  
R. Reid ◽  
B. Clark ◽  
R. Dent

In response to the need to find better adapted and more persistent perennial pasture plants for the dryland pastures in the cool-temperate low to medium rainfall (500-700 mm) regions, over 1000 accessions representing 24 species of perennial legumes and 64 species of perennial grasses, were introduced, characterised and evaluated for production and persistence under sheep grazing at sites throughout Tasmania. The work has identified four alternative legume species in Talish Clover (Trifolium tumens). Caucasian Clover (T. ambiguum), Stoloniferous Red Clover (T. pratense var. stoloniferum), Lucerne x Yellow Lucerne Hybrid (Medicago sativa x M.sativa subsp. falcata); and two grass species in Coloured Brome (Bromus coloratus) and Hispanic Cocksfoot (Dactylis glomerata var hispanica). Keywords: persistence, perennial grass, perennial legume


2006 ◽  
Vol 54 (7) ◽  
pp. 655 ◽  
Author(s):  
Tanja I. Lenz ◽  
José M. Facelli

The species composition of temperate grasslands in the mid-north of South Australia has been radically altered from a system dominated by native perennial grasses to a system dominated by Mediterranean annual grasses. This study investigated the importance of chemical and physical soil characteristics, topographical features and climatic variables on the abundance of native and exotic grass species in nine ungrazed grasslands. Overall, climatic and other abiotic factors were highly variable. In addition, past management practices and original species composition are generally unknown, leading to further unexplained variation in the data. On a large spatial scale (among sites), the abundance of exotic annual grasses was positively correlated with mean annual rainfall, and on any scale, with finer soil textures and higher soil organic carbon levels. The most abundant annual grass, Avena barbata (Pott ex Link), was generally associated with soil factors denoting higher soil fertility. The abundance of native perennial grass species was not correlated with any environmental variables at any scale. The various native perennial grass species did not show clear associations with soil factors, although they tended to be associated with factors denoting lower soil fertility. However, at small spatial scales (within some sites) and among sites, the abundances of exotic annual and native perennial grasses were strongly negatively correlated. The results suggest that at the present time, rainfall and soil properties are important variables determining the abundance of annual grasses. The driving variables for the abundance of perennial grasses are less clear. They may be controlled by other factors or extreme rainfall events, which were not surveyed. In addition, they are likely to be controlled by competitive interactions with the annual grasses.


2018 ◽  
Vol 11 (4) ◽  
pp. 201-207
Author(s):  
Parmeshwor Aryal ◽  
M. Anowarul Islam

AbstractForage kochia [Bassia prostrata(L.) A. J. Scott] is competitive with annual weeds and has potential for use in reclamation of disturbed land. However, land managers are reluctant to use forage kochia in revegetation programs due to lack of understanding of its compatibility with or invasiveness in the native plant community. We conducted two greenhouse experiments, one to compare the competitive effect of forage kochia versus perennial grasses on growth of cheatgrass (Bromus tectorumL.) and one to study the effect of forage kochia on growth of native perennial grasses. In the first experiment, a single seedling ofB. tectorumwas grown with increasing neighbor densities (0 to 5 seedlings pot−1) of either forage kochia, crested wheatgrass [Agropyron cristatum(L.) Gaertner ×A. desertorum(Fisch. ex Link) Schultes; nonnative perennial grass], or thickspike wheatgrass [Elymus lanceolatus(Scribn. & J. G. Sm.) Gould; native perennial grass].Bromus tectorumgrowth was reduced moderately by all three perennial neighbors, butA. cristatumandE. lanceolatushad more effect onB. tectorumwhen compared with forage kochia. This experiment was repeated and similar results were observed. In the second experiment, forage kochia was grown with each of four native cool-season grass species: basin wildrye [Leymus cinereus(Scribn. & Merr.) Á. Löve], bluebunch wheatgrass [Pseudoroegneria spicata(Pursh) Á. Löve],E. lanceolatus, and western wheatgrass [Pascopyrum smithii(Rydb.) Á. Löve]. Forage kochia had no effect on height, tiller number, and aboveground biomass of native grasses. Similarly, native grasses did not show a significant effect on forage kochia seedlings. This experiment was also repeated, and forage kochia somewhat reduced the aboveground biomass ofL. cinereusandP. spicata. However, all native grasses significantly reduced change in height, branching, and aboveground biomass of forage kochia. These results suggest that forage kochia interfered withB. tectorumseedling growth, but it showed little competitive effect on native grass seedlings.


2003 ◽  
Vol 54 (9) ◽  
pp. 903 ◽  
Author(s):  
S. P. Boschma ◽  
M. J. Hill ◽  
J. M. Scott ◽  
G. G. Rapp

A field experiment was conducted to study the effects of defoliation and moisture stresses on perennial pasture grasses and to identify traits associated with their resilience. The experiment, conducted near Armidale on the Northern Tablelands of NSW, studied 4 introduced perennial grass species (Phalaris aquatica, Festuca arundinacea, Dactylis glomerata, and Lolium perenne) and 2 native grass species (Microlaena stipoides and Austrodanthonia richardsonii) subjected to 3 moisture regimes (non-stress moisture, moderate drought, and severe drought) and 2 defoliation intensities (severe and moderate). Basal area, herbage mass, phenological growth stage, nitrogen concentration, root mass, and rooting depth were compared over 2 independent 6-month periods: spring–summer (1 September 1994–28 February 1995) and summer–autumn (1 December 1994–31 May 1995). Multiple regression was used to determine which traits were important for determining plant resilience.The differences between species and their respective responses were evident in the traits measured. In general, basal area tended to increase over summer and show little change during autumn. Severe defoliation stimulated plant growth, resulting in higher harvested herbage mass than from those moderately defoliated. Reproductive development was suppressed by severe drought and reduced by moderate drought. Severe defoliation suppressed flowering of Dactylis and Lolium at both drought intensities, compared with moderate defoliation. Phalaris, Festuca, and Austrodanthonia were the deepest rooting species during spring–summer, and Dactylis the shallowest. All species had similar rooting depths during summer–autumn, with those under severe and moderate drought having the deepest and shallowest rooting, respectively.Carbohydrate reserves and basal area were important traits for determining plant resilience during spring–summer. During summer–autumn, maintaining basal area and plant biomass through moderate grazing was important for resilience.


2013 ◽  
Vol 61 (5) ◽  
pp. 383 ◽  
Author(s):  
Ana M. Cenzano ◽  
M. Celeste Varela ◽  
Mónica B. Bertiller ◽  
M. Virginia Luna

Poa ligularis Nees. Ap. Steudel and Pappostipa speciosa (Trin. et Rupr.) Romaschenko are dominant perennial grasses in the arid Patagonian rangelands of Argentina. Both species are exposed to periods of water shortage during spring-summer and are grazed by domestic and native herbivores. Pappostipa speciosa displays xeromorphic adaptations and is less preferred by herbivores than P. ligularis. The knowledge of how drought affects morphological/functional traits in coexisting perennial grass species is useful to understanding the function of desert perennial grasses, and for the use and conservation of Patagonian arid rangelands. The hypothesis of this study was that co-existing perennial grasses contrasting in drought resistance mechanisms display different degrees of phenotypic plasticity in underlying and/or functional traits. Plants of both species were exposed to two levels of gravimetric soil moisture: 16% (~field capacity) and 4%. Plant vegetative and reproductive traits were measured weekly in individual plants and these were harvested at the end of the experiment. Aboveground and root biomass were separated in the harvested plants and the concentration of photosynthetic pigments was assessed in green leaves. The trait response range was also calculated through the plasticity index. In both species, drought stress led to significant reductions in plant height, total plant dry weight, number of total leaves, dry weight of green and senescent leaf, percentage of flowering plants, length of inflorescences, and number, length and dry weight of roots. The concentration of photosynthetic pigments increased under drought in both species. In conclusion, drought strongly affected reproductive and vegetative traits in both species and the greatest negative effect of drought was found in P. speciosa, the most conservative species. However, our findings might indicate that both species are able to maintain photosynthetic activity through the increase of photosynthetic pigments under drought conditions in Patagonian rangelands.


1956 ◽  
Vol 7 (5) ◽  
pp. 367 ◽  
Author(s):  
WD Andrew ◽  
CA Neal-Smith

Over the period 1952-1954 there was no significant difference in the yield of herbage produced annually by the addition to a Phalaris tuberosa L.–Trifolium subterraneum L. pasture mixture, of any one of the following grasses: Agropyron obtusiusculum Lange., Bromus coloratus Steud., Bromus inermis Leyss., Dactylis glomerata L., or Festuca arundinacea Schreb. There were indications of a small change in seasonal production where certain grasses, notably D. glomerata, were included in the mixture. Over the 3-year period the proportion of the sown grass component, in the mixtures where either D. glomerata, B. inermis, or B. coloratus were included, increased by a greater amount than where the simple mixture of phalaris and subterranean clover was used. The addition of each grass also lessened the amount of P. tuberosa in the sown grass component of the yield. In the third year, despite the varying proportions of the phalaris and associated sown grass species, the mean population of the sown perennial grasses in each treatment did not differ significantly from the mean figure of 1.34 plants/sq. lk. The increased production of the sown grass yield component following the association of certain of the above species with P. tuberosa suggests that the latter does not fully exploit the environment. The principle of including another perennial grass when sowing phalaris and subterranean clover might have wide application as a means of combatting "phalaris staggers".


2009 ◽  
Vol 31 (4) ◽  
pp. 369 ◽  
Author(s):  
A. M. Bowman ◽  
Y. Alemseged ◽  
G. J. Melville ◽  
W. J. Smith ◽  
F. Syrch

Native grass-based pastures in the 400–600 mm rainfall zone of central NSW are an important basis for extensive grazing industries. However, over time they have been invaded by exotic weeds. This study aimed to evaluate several grazing strategies for the maintenance or improvement of native grasslands based on pasture productivity and species diversity. Seven grazing strategies, ranging from set stocking to permanently removing stock, were employed to evaluate the strategy that would best maintain a high proportion of desirable perennial grass species. Grazing treatments were evaluated based on their effects on pasture composition and on the density of selected key grass species such as Enteropogon acicularis (Lindl.) Lazar. (curly windmill grass). Managing the utilisation of the key desirable species E. acicularis combined with weed control was the most successful strategy in terms of increasing the density of the key species, although no treatment increased the proportion of desirable perennial grasses and desirable broadleaf species. This was followed by a ‘farmer’s choice’ strategy, which involved combining phosphorus fertiliser application, weed control and rest from grazing. In contrast, strategies that involved either a ‘summer lockup’ or ‘weed control’ alone performed poorly. It is concluded that native pastures in this region could be rehabilitated, and their productivity restored, by following strategies that provide rest from grazing, based on the utilisation levels of key, species combined with control of annual weeds.


2006 ◽  
Vol 46 (5) ◽  
pp. 637 ◽  
Author(s):  
B. S. Dear ◽  
G. A. Sandral ◽  
B. C. D. Wilson

The tolerance of 5 perennial grasses during the seedling stage to pre- and post-emergent grass herbicides was examined in 3 glasshouse experiments. The perennial grass species screened were phalaris, (Phalaris aquatica L.), cocksfoot (Dactylis glomerata L.), wallaby grass [Austrodanthonia richardsonii (Cashm.) H.P. Linder], perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea Schreb.). Wheat (Triticum aestivum L.) and subterranean clover (Trifolium subterraneum L.) were included as non-target species and annual ryegrass (Lolium rigidum Gaudin) and oats (Avena spp.) as representatives of typical weed species. Herbicides evaluated were fluazifop-p, tralkoxydim, diclofop-methyl, fenoxaprop-p-ethyl, fenoxaprop-p-ethyl + pyrazoline, sethoxydim, flamprop-m-methyl, quizalofop-p-ethyl, clethodim, simazine, imazethapyr, propyzamide, carbetamide, clodinafop-propargyl + cloquintocet-mexyl, propaquizafop, atrazine, trifluralin, triallate, pendimethalin, metribuzin, trifluralin + oryzalin, cyanazine, chlorsulfuron and triasulfuron. Herbicide phytotoxicity was assessed 15 and 30 days after post-emergent herbicide application using the European Weed Research Committee (EWRC) visual score of leaf damage (1 indicating no effect, 9 indicating all plants dead) and plant herbage yield depression relative to the unsprayed control. Plant responses to pre-emergent herbicides were assessed 45 days after sowing. Most herbicides were highly phytotoxic (EWRC score 4–9) to the perennial grass seedlings. However, atrazine, flamprop-m-methyl, imazethapyr, fenoxaprop-ethyl, and triallate caused less severe phytotoxicity (EWRC score 1–4) in phalaris, fescue, cocksfoot and perennial ryegrass from which they could be expected to recover, with yield reductions of between 0 and 45%, 30 days after spraying. Simazine caused yield losses of 20–50% in fescue, phalaris and perennial ryegrass which may be acceptable in swards with high weed burdens. Wallaby grass showed tolerance to flamprop-m-methyl, carbetamide, propyzamide and imazethapyr. Subterranean clover was tolerant of most herbicides with yield losses less than 20% except for the post-emergent herbicides simazine and atrazine, and the pre-emergent herbicides triasulfuron, metribuzin, cyanazine and chlorsulfuron where yield suppression was between 50 and 99%.


2000 ◽  
Vol 40 (2) ◽  
pp. 299 ◽  
Author(s):  
J. M. Virgona ◽  
A. Bowcher

The response to variation in grazing interval over the spring–autumn period in southern New South Wales was examined on 4 perennial grass species over 2 years. Plots of phalaris (Phalaris aquatica L. cv. Sirolan), cocksfoot (Dactylis glomerata L. cv. Porto), tall fescue (Festuca arundinacea Shreb cv. Demeter) and a native danthonia (Danthonia richardsonii cv. Taranna), were grazed by sheep every 2, 5 or 8 weeks, either rainfed or given supplementary irrigation. Basal cover was monitored over this period and is combined with measurements of phenological development and herbage mass to explain differences in persistence. The seasons differed with respect to rainfall, 1994–95 being dry compared to 1995–96. Over the 1994–95 season, the relative change in basal cover [RCBC, the ratio of final (May 1995) to initial (September 1994) basal cover] of the 3 introduced perennial grasses was significantly less than 1, which indicated a decline in basal cover over the measurement period. In contrast, RCBC was 1.55 for danthonia. Grazing interval treatments significantly affected RCBC in 1994–95, RCBC increasing with grazing interval. In the 8-week grazing interval, RCBC did not significantly differ from 1. Changes in density were also measured in 1994–95 and followed a similar pattern to RCBC for species effects although there was no significant effect of grazing interval. In 1995–96, there were interactions between watering and both species and grazing interval. The RCBC (September 1995–May 1996) was significantly greater than 1 for cocksfoot and tall fescue under irrigated conditions but not under rainfed conditions. The response to grazing interval depended on water supply. The 5-week grazing interval led to the highest RCBC under both rainfed and irrigated conditions. However, when rainfed, the 5- and 8-week treatments were not significantly different, whereas under irrigation, the 2- and 5-week treatments did not significantly differ. For the 1995–96 season, a movement index (MI, ratio of newly colonised area to that occupied throughout the season) was measured. There was a strong interaction between species and watering but phalaris was the most mobile (highest MI) of the 4 species under both rainfed and irrigated conditions. The absence of any interaction between species and grazing interval in either 1994–95 or 1995–96 suggests that response to grazing of these species may be similar despite differences in survival mechanisms.


1987 ◽  
Vol 67 (3) ◽  
pp. 755-763 ◽  
Author(s):  
A. L. DARWENT ◽  
H. G. NAJDA ◽  
J. C. DRABBLE ◽  
C. R. ELLIOTT

The effect of row spacing on seed and hay yields of 11 perennial grass species, including crested wheatgrass (Agropyron cristatum L.), intermediate wheatgrass (A. intermedium (Host.) Beauv.), a northern biotype of bromegrass (Bromus inermis Leyss.), a southern biotype of bromegrass, Russian wildrye (Elymus junceus Fisch.), meadow fescue (Festuca pratensis Hudson), creeping red fescue (F. rubra var. genuina L.), chewings fescue (F. rubra var. commutata Gaud), reed canary grass (Phalaris arundinacea L.), a turf-type timothy (Phleum bertolonii DC (P. bulbosum auct.)) and hexaploid timothy (Phleum pratense L.), was studied under a system with limited inputs of fertilizer and no weed control. The width of the row spacings ranged from 16 to 104 cm where seed yields were measured and from 27 to 93 cm where hay yields were measured. The seed yield of all grasses was greater at a row spacing of 16 cm than at row spacings of 60 cm or more. Hay yields of all grasses, averaged over four production years, were also greatest at narrow row spacings (27 cm). These yields decreased as row spacings increased to 49 through 93 cm. Row spacing had its greatest effect on hay yields during the first production year. After this period the effects of row spacing on hay yields were small.Key words: Row spacing, perennial grasses, seed yields, hay yields


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