Effects of grazing interval on basal cover of four perennial grasses in a summer-dry environment

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.


2003 ◽  
Vol 54 (8) ◽  
pp. 819 ◽  
Author(s):  
S. P. Boschma ◽  
J. M. Scott ◽  
M. J. Hill ◽  
J. R. King ◽  
J. J. Lutton

The effects of defoliation intensity and drought severity on levels of water-soluble carbohydrate (WSC), fructan, and etiolated regrowth of 6 important perennial grasses were investigated. The experiment was conducted under a rain-out shelter at Armidale, NSW, Australia, using 6 perennial grass species (Phalaris aquatica cv. Sirosa, Festuca arundinacea cv. Demeter, Dactylis glomerata cv. Porto, Lolium perenne cv. Victorian, Microlaena stipoides cv. Shannon, and Austrodanthonia richardsonii cv. Taranna) subjected to 3 moisture regimes (non-stress moisture, and moderate and severe drought) and 2 defoliation intensities (moderate and severe) over 2 seasonal sequences (spring–summer and summer–autumn).The range in WSC, fructan, and etiolated regrowth of the species varied, with Festuca and Lolium having the highest WSC and fructan concentrations. Austrodanthonia had the lowest WSC concentration of the species. Unlike the introduced species, the natives did not store fructans. The species varied in their response to the treatments imposed. Festuca and Phalaris had the highest etiolated regrowth and showed the greatest effect of defoliation intensity. Etiolated regrowth appeared to be a sensitive measure of plant status, showing the fragile nature of some of the species.The effect of defoliation intensity and drought varied with season. Defoliation intensity had little effect on carbohydrate reserves of all species, except Festuca, during summer of the spring–summer experimental season. During the summer–autumn experimental season, severe defoliation reduced the rate of accumulation during the period December–April. Drought affected carbohydrate accumulation and utilisation. Carbohydrates that had been accumulated at the end of spring of the spring–summer experimental season in plants affected by drought were utilised during summer. However, if drought commenced in summer, carbohydrate accumulation continued for 120 days in all species studied, and 180 days in Lolium and Phalaris.Autumn appeared to be a period when plant reserves were particularly susceptible to stress. The importance of WSC, fructans, and etiolated regrowth as measures of plant reserves, and their role in persistence were discussed.



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.



2002 ◽  
Vol 42 (4) ◽  
pp. 431 ◽  
Author(s):  
G. M. Lodge

A split-plot experiment was sown at Tamworth in 1992 to examine the effects of continuous sheep grazing and seasonal closures (autumn, spring, spring + autumn, and summer + winter) on the herbage mass, plant frequency and basal cover of 5 perennial grasses, when sown as monocultures or with a perennial (Trifolium repens cv. Haifa) or annual legume (Trifolium subterraneum var. subterraneum cv. Seaton Park). Plant basal area and crown density data were also collected. The perennial grasses were Phalaris aquatica cv. Sirosa, Festuca arundinacea, cv.� Demeter, Lolium perenne cv. Kangaroo Valley, Austrodanthonia richardsonii (syn. Danthonia richardsonii) cv.�Taranna, and A. bipartita (syn. D. linkii) cv. Bunderra. There was no significant effect of legume presence on the herbage mass or persistence of the perennial grasses. The only treatment that had a significant effect (P< 0.05) on either herbage mass, plant frequency or basal cover data was the grazing treatment × perennial grass interaction in each of the years 1993-98, except for herbage mass in December 1993 and basal cover in October 1998. In all of the grazing treatments examined, Kangaroo Valley ryegrass failed to persist after spring 1994; Demeter fescue had failed by spring 1997 and Sirosa phalaris by spring 1998. Six years after sowing the only temperate grass cultivars that were persisting in all grazing treatments were the native perennials, Taranna and Bunderra. Hence, the data represent the entire stand life from sowing to eventual failure for the 3 introduced cultivars. While grazing treatment effects within years for individual species were significant, overall grazing had little effect on the rate of decline in herbage mass and persistence of Kangaroo Valley, Demeter and Sirosa. By 1998, grazing treatment had no significant effect on the herbage mass and basal cover of Taranna and Bunderra, but their plant frequencies were lowest in the spring rest and summer + winter rest treatments.



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".



2002 ◽  
Vol 82 (1) ◽  
pp. 89-92 ◽  
Author(s):  
J. R. Moyer ◽  
A. L. Boswall

Foxtail barley (Hordeum jubatum L.) is a troublesome weed in irrigated pastures. Several grass species seeded on two irrigated pastures at Lethbridge to test their ability to compete with foxtail barley. Tall fescue (Festuca arundinacea Schreb.) and creeping foxtail (Alopecurus arundinaceus Poir) reduced foxtail barley groundcover significantly compared to orchardgrass (Dactylis glomerata L.), pubescent wheatgrass (Agropyron trichophorum (Link) Richt.) and western wheatgrass (Agropyron smithii Rydb.); therefore, seeding of these grasses in areas subject to foxtail barley invasion should be encouraged. Key words: Foxtail barley, tall fescue, creeping foxtail, wet soils, salinity, weed suppression



HortScience ◽  
2011 ◽  
Vol 46 (10) ◽  
pp. 1404-1410 ◽  
Author(s):  
Rebecca Nelson Brown ◽  
Josef H. Gorres

Highway rights-of-way are routinely planted with turfgrasses to prevent erosion, filter runoff, and improve aesthetics. However, the roadside is a harsh environment, and perennial grasses often die within the first year, leading to bare ground and annual weeds, which do not prevent erosion during the winter. To improve the survival of perennial vegetation on the roadside, it is necessary to identify the factors limiting vegetation growth and then to either identify plants that can tolerate those factors or identify ways to ameliorate the stresses while still maintaining safety. This study was designed to evaluate the effects of improved cultivars, salt tolerance, and organic matter amendments on perennial grass survival along two highways in Rhode Island. The amendments tested were processed biosolids and composted yard waste, each applied in a 50:50 mixture by volume with existing roadside soil; plain soil was included as a control. We tested 20 improved turfgrass cultivars and one seed mixture with common creeping red fescue (Festuca rubra L.) as the standard. Turfgrass species tested were perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea Schreb.), red fescue, alkali grass [Puccinellia distans (Jacq.) Parl.], idaho bentgrass (Agrostis idahoensis Nash), tufted hairgrass [Deschampsia cespitosa (L.) P. Beauv.], and kentucky bluegrass (Poa pratensis L.). We found that soil amendment was more effective than either improved genetics or salt tolerance. Establishment, vertical growth, and persistence of vegetation cover were significantly improved by amendment with organic matter, particularly biosolids. In Summer 2009 (the second growing season), turf cover exceeded 50% in the biosolids plots but was below 20% in the plain soil plots with complete loss of cover in the plain soil plots at one location. Kentucky bluegrass, tall fescue, red fescue, and idaho bentgrass showed the best persistence at the species level, and there were no consistent differences among cultivars.



1989 ◽  
Vol 40 (2) ◽  
pp. 301 ◽  
Author(s):  
WD Bellotti ◽  
GJ Blair

'Demeter' tall fescue (Festuca arundinacea Schreb.) and 'Victorian' perennial ryegrass (Lolium perenne L.) were sown separately into a white clover (Trifolium repens L.) dominant pasture in June 1981. Eight sowing methods were compared to assess the ability of perennial grasses to establish from direct drill sowing methods relative to conventional seedbed and aerial sowing methods. Within direct drill treatments, two drill implements were factorially combined with three herbicide treatments. Pasture production and botanical composition were sampled over a 27 month period following sowing. After a dry summer, 22 months after sowing, sown grasses dominated pasture composition (69-94% of total dry matter yield) in the high yielding treatments. At this time, the successful direct drill treatments were similar in yield to the conventional seedbed treatment. Within direct drill treatments, sowing implement had little effect on yield and composition, whereas herbicide application markedly increased sown grass yield. Pre-sowing blanket application of herbicide in the triple disc treatment increased tall fescue yield from 82 to 1504 kg ha-1 and perennial ryegrass yield from 98 to 807 kg ha-1. An inverse relationship was described between dry matter present at sowing and eventual yield of sown grasses. These perennial grasses can be successfully established by using direct drill sowing methods provided resident vegetation is adequately suppressed.



2004 ◽  
Vol 55 (3) ◽  
pp. 345 ◽  
Author(s):  
G. M. Lodge

A series of seed and seedling studies was undertaken in northern New South Wales for the temperate perennial grasses phalaris (Phalaris aquatica cv. Sirosa and Australian), tall fescue (Festuca arundinacea cv. Demeter), perennial ryegrass (Lolium perenne cv. Kangaroo Valley), and 2 wallaby grasses (Austrodanthonia bipartita syn. Danthonia linkii cv. Bunderra and A. richardsonii syn. D. richardsonii cv. Taranna). Studies were conducted to determine the level of dormancy in freshly harvested seed and the time required to overcome it, effects of alternating daily temperatures on the germination of non-dormant seed, effect of time-of-sowing on seedling emergence (2 studies) and survival, levels of seed production and soil seedbanks, and the effect of litter cover and soil type on the emergence of Sirosa phalaris seedlings.Grass species, time, and their interaction all had a significant effect (P < 0.05) on both dispersal unit and caryopses germination. One month after harvest, germination of caryopses was lower (P < 0.05, 2 and 1%, respectively) for Taranna and Bunderra than for Sirosa (79.5%). In March 1993, germination of the 2 wallaby grasses was also lower (P < 0.05) than that of Sirosa. Dormancy of freshly harvested seeds of Sirosa was mainly associated with the structures surrounding the caryopses (7.7 v. 79.5% mean germination), but for Taranna and Bunderra it was related to physiological dormancy of the caryopses.Germination levels that were not significantly different to the maximum occurred for temperature ranges of 35/30–15/10�C [Sirosa (commercial)], 35/25–15/10�C (Australian phalaris), and 35/30–15/05�C (Kangaroo Valley ryegrass). In contrast, maximum germination of wallaby grasses only occurred for Taranna in the temperature range 25/20–20/10�C, and for Bunderra at 25/15 and 20/15�C.Seedling emergence in the field was episodic, occurring on only 3 occasions from 1993 to 1996. No seedlings of Sirosa phalaris, Demeter tall fescue, or Kangaroo Valley ryegrass were successfully recruited, but Taranna and Bunderra successfully recruited new plants from natural seedfalls. Whereas seed production of the perennial grasses studied was relatively high (~10 000 seed/m2 in 1992), soil seedbank levels were much lower (generally <1000 seeds/m2). These data were used to indicate the likely successful establishment of sown perennial grasses or by regeneration from natural seedfall.



2008 ◽  
Vol 48 (4) ◽  
pp. 578 ◽  
Author(s):  
B. S. Dear ◽  
K.F. M. Reed ◽  
A. D. Craig

The potential adaptation of a range of perennial pasture species to recharge environments in southern Australia is reviewed based on their performance in 20 field nurseries in a nationally coordinated project. Species were also evaluated for their suitability to discharge sites where salt and waterlogging are major restraints. Species are ranked according to their potential to be incorporated into farming systems and the scope for further breeding and selection. Medicago sativa L. (lucerne) was the most persistent of the perennial legumes across a diversity of recharge environments. Lotus corniculatus L. (birdsfoot trefoil) showed the most promise on soils prone to waterlogging. Other legumes that showed potential included Cullen australasicum (Schltdl.) J.W. Grimes (tall verbine) and Lotononis bainesii Baker (lotononis). The herb Chicoriyum intybus L. was superior to M. sativa on more acid soils. Phalaris aquatica L. (phalaris) and summer dormant cultivars of Dactylis glomerata L. (cocksfoot), Festuca arundinacea L. (tall fescue) and Lolium perenne L. (perennial ryegrass) were among the most persistent and productive of the perennial grasses. Further exploitation of temperate perennial grass germplasm with increased summer dormancy should be a priority to increase the role of these grass species in lower rainfall, summer-dry environments. Although difficult to establish, the indigenous grasses Austrodanthonia caespitosa (Gaudich.) H.P. Linder (wallaby grass) and A. richardsonii (Cashmore) H.P. Linder were persistent and showed good recruitment. They should be a priority for low rainfall, low input environments. Other grasses that showed promise were Chloris gayana Kunth (Rhodes grass), Secale montanum Guss. (mountain rye), Microlaena stipoides (Labill.) R. Br. (weeping grass), Ehrhata calcycina Sm. (veldt grass) and Bromus stamineus E. Desv. (grazing brome). For discharge environments, Melilotus siculus (Turra) Vitman ex B.D. Jacks. was one of the most salt tolerant legumes and should be a priority for further development. Medicago polymorpha L. (burr medic) appears underutilised in discharge environments. Increasing the waterlogging tolerance of this moderately salt tolerant species would further enhance its potential. Trifolium michelianum Savi. (balansa clover) owed its success in discharge areas more to ‘salt avoidance’ rather than salt tolerance per se. Melilotus sulcatus Desf., T. tomentosum L. and Lotus tenuis Waldst. & Kit. ex Willd. also had traits that may prove advantageous for discharge environments. Within the pasture grasses, Puccinellia ciliata Bor (pucinellia) was superior at sites prone to waterlogging whereas T. ponticum performed better in moderately drained saline sites.



1997 ◽  
Vol 37 (5) ◽  
pp. 547 ◽  
Author(s):  
P. J. Vickery ◽  
M. J. Hill ◽  
G. E. Donald

Summary. Spectral data from the green, red and near-infrared bands of Landsat MSS and Landsat TM satellite imagery acquired in mid-spring were classified into 3 and 6 pasture growth classes respectively. The classifications were compared with a site database of botanical composition for the Northern Tablelands of New South Wales to examine the association between spectral growth class and pasture composition. Pastures ranged in composition from unimproved native perennial grasses through semi-improved mixtures of native and naturalised grasses and legumes to highly improved temperate perennial grasses and legumes. For 3 years of MSS data, the fast growth class had a mean botanical composition of about 80% improved perennial grass and 0% native; medium growth class averaged 46% improved perennial grass and 14% native; while the slow growth class had about 60% native and 1% improved perennial grass when averaged over 3 years of MSS data. For the 6 class TM data from a single year, a predictive logistic regression of cumulative probability was developed for percentage of ‘very fast’ growth pixels and ordered 10 percentile categories of improved perennial grass or native grass. Differences in patch characteristics between classes with MSS disappeared with TM reclassified to the same 3 class level. Most probable pasture type was inferred from 3 class MSS and TM data using Bayesian probability analysis. The resulting maps were similar in general appearance but detail was better with the TM data. The pasture growth classification identified highly improved perennial grass pastures and native pastures but sensitivity to intermediate pasture types was poor. Future improvement will come from direct measurement of biophysical characteristics using vegetation indices or inversion of reflectance models.



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