scholarly journals Changes in yellow bristle grass (Setaria pumila) abundance after drought implications for pasture management

2009 ◽  
Vol 62 ◽  
pp. 211-216 ◽  
Author(s):  
K.N. Tozer ◽  
T.K. James ◽  
C.A. Cameron
Keyword(s):  
Key Management ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Annual Grass ◽  
Bare Ground ◽  
Pasture Management ◽  
Soil Calcium ◽  
Annual Grasses ◽  
Previous Summer

Yellow bristle grass (YBG) which is a summeractive annual grass reduces pasture quality and becomes unpalatable to stock as panicles mature Farmers are concerned that an extreme drought from November 2007 to March 2008 may have facilitated the spread of YBG and other summeractive annual grass weeds Botanical composition was assessed on 12 Waikato dairy farms in February 2009 and YBG abundance was related to key management factors These findings were compared with data collected from the same farms (February 2008) during the drought Between years ryegrass cover and the proportion of bare ground decreased These components were replaced by two summeractive annual grasses YBG and summer grass and to a lesser extent summeractive perennial grasses clovers and dicots In 2009 YBG cover was negatively associated with summeractive perennial grass cover and pH and positively associated with YBG cover in the previous summer and soil calcium levels

Changes in the Quantitative Floristics in Some Astrebla Spp. (Mitchell Grass) Communities in South-Western Queensland in Relation to Trends in Seasonal Rainfall

1981 ◽  
Vol 29 (5) ◽  
pp. 533 ◽  
Author(s):  
DM Orr
Keyword(s):  
Relative Abundance ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Seasonal Rainfall ◽  
Individual Species ◽  
Botanical Composition ◽  
Basal Cover ◽  
Wide Range ◽  
Annual Grasses

Seasonal changes in the quantitative floristics at a wide range of Astrebla grassland sites in south-western Queensland were monitored between 1972 and 1980 with a wheel point apparatus. Changes in the floristics were measured in terms of both relative abundance and basal cover. A large increase in the relative abundance of perennial grasses, particularly Aristida latifolia, Astrebla spp. and Dichanthium sericeum, occurred between 1972 and 1976. This increase was at the expense of annual grasses and forbs which declined in both relative abundance and number of genera present. The relative abundance of perennial grasses declined between 1978 and 1980 and this was associated with a large increase in the forbs such as Daucus glochidiatus and Plantago spp., particularly at southern sites. The contribution of annual grasses to botanical composition remained low throughout the period. Total basal cover differed between years although these differences were not significant. As perennial grass, particularly Astrebla spp., was the major vegetation component of total basal cover, changes in the latter were associated mainly with changes in the basal cover of Astrebla spp. Changes in the contribution of individual species to total basal cover were related to changes in the relative abundance of those species. Changes in botanical composition in Astrebla grassland may be influenced more by trends in seasonal rainfall than by grazing pressure.

Effects of perennial species on the demography of annual grass weeds in pastures subject to seasonal drought and grazing

2009 ◽  
Vol 60 (11) ◽  
pp. 1088 ◽  
Author(s):  
K. N. Tozer ◽  
D. F. Chapman ◽  
R. D. Cousens ◽  
P. E. Quigley ◽  
P. M. Dowling ◽  
...  
Keyword(s):  
Population Growth ◽  
Field Experiment ◽  
Perennial Grass ◽  
Dactylis Glomerata ◽  
Suppressive Effect ◽  
Perennial Grasses ◽  
Perennial Species ◽  
Annual Grass ◽  
Annual Grasses ◽  
Hordeum Leporinum

A field experiment was established in a southern Australian temperate pasture to investigate the effects of identity and proximity of perennial grasses on the demography of the annual grasses Vulpia spp. (V. myuros, V. bromoides) and Hordeum leporinum (barley grass). Annual grasses were grown either alone or in mixtures, at different distances from rows of Dactylis glomerata (cocksfoot) and Phalaris aquatica (phalaris). Dactylis had a greater suppressive effect than Phalaris on Vulpia and Hordeum. Biomass, tiller production, and panicle production of annual grasses increased linearly with increasing distance from the perennial row. Tiller and panicle production were greater for Vulpia than Hordeum. The estimated rate of population growth (λ) for annual grasses was greater in Phalaris than in Dactylis and in Vulpia than in Hordeum, and increased with sowing distance from perennial grass rows. It was estimated that λ, when seeds were sown directly adjacent to a row of perennial grasses, was 1 and 0.4 for Vulpia and Hordeum, respectively, within Dactylis stands, and 7 and 3, respectively, within Phalaris stands. However, 15 cm from the row, λ reached 50 and 39 for Vulpia and Hordeum, respectively, within Phalaris stands, and 39 and 16, respectively, within Dactylis stands. In grazed, dryland pastures, perennial competition alone is therefore unlikely to prevent population growth of annual grasses, especially in systems heavily disturbed by grazing or drought. However, Dactylis showed more promise than Phalaris in limiting the abundance of these weeds.

Medusahead Control with Fall- and Spring-Applied Herbicides on Northern Utah Foothills

2005 ◽  
Vol 19 (3) ◽  
pp. 653-658 ◽  
Author(s):  
Thomas A. Monaco ◽  
Travis M. Osmond ◽  
Steven A. Dewey
Keyword(s):  
Perennial Grass ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Primary Concern ◽  
Annual Grass ◽  
Bare Ground ◽  
Prescribed Burns ◽  
Northern Utah ◽  
Winter Annual ◽  
Second Year

Medusahead is an aggressive, nonnative, winter annual grass that infests rangelands in the western United States. Its ability to rapidly spread, outcompete native vegetation, and destroy forage potential is a primary concern for landowners and land managers exposed to this weed. Prescribed burns were conducted at a low- and high-litter site in northern Utah prior to conducting experiments to evaluate the effects of fall and spring applications of sulfometuron at 39 or 79 g ai/ha and imazapic at 70 or 140 g ai/ha on medusahead and associated perennial grasses, annual and perennial forbs, and bare ground cover. Large differences in pretreatment medusahead litter between the sites resulted in less surface area burning at the low-litter site (∼10%) compared to the high-litter site (∼80%). Higher herbicide rates significantly increased medusahead control and bare ground cover; however, this rate affect largely depended on site, season, and herbicide. The low- and high-litter sites did not differ significantly in perennial grass cover 2 yr after burning. Annual forb cover was greater, but perennial forb cover was lower at the low-litter site compared to the high-litter site. Several treatment combinations were identified as having the potential to maintain greater than 50% medusahead control in the second year after herbicide applications. These results collectively demonstrate that potential exists to successfully control medusahead and produce a window of opportunity to reintroduce a greater abundance of perennial species back into the plant community via seeding.

scholarly journals Botanical and management factors associated with Setaria pumila abundance implications for pasture management

2008 ◽  
Vol 61 ◽  
pp. 121-126 ◽  
Author(s):  
K.N. Tozer ◽  
T.K. James ◽  
C.A. Cameron
Keyword(s):  
Key Management ◽  
Control Strategies ◽  
Dairy Farms ◽  
Effective Control ◽  
Bare Ground ◽  
Pasture Management ◽  
Annual Grasses ◽  
Forage Intake ◽  
Management Factors ◽  
Significant Production

Yellow bristle grass (YBG) causes significant production loss on dairy farms as it is unpalatable to stock and can reduce forage intake and milk production This weed is rapidly spreading in North Island dairy pastures and effective control strategies are needed Botanical surveying was undertaken in February 2008 on 12 dairy farms in Waikato to ascertain its presence in pastures in relation to key management factors YBG cover was negatively associated with Olsen P pH paspalum cover and postgrazing residual dry matter in January Stocking rate time since pasture renovation inclusion of a cropping phase prior to renovation sowing rate during renovation ryegrass undersowing after renovation and cover of ryegrass clovers other dicots annual grasses and amount of bare ground had no significant effect on YBG cover Results suggest that while improved soil fertility and increasing pasture competition will enhance YBG control YBG seeds can survive during pasture renovation leading to rapid reinfestation of pastures

Population dynamics and stability of Stylosanthes hamata cv. Verano in grazed pastures

1982 ◽  
Vol 33 (1) ◽  
pp. 63 ◽  
Author(s):  
CJ Gardener
Keyword(s):  
Perennial Grass ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Grazed Pastures ◽  
Stylosanthes Hamata ◽  
Wide Range ◽  
Annual Grasses ◽  
Seed Reserves ◽  
Stable Association

The longevity, regeneration and seed reserves of Stylosantes hamata cv. Verano were studied in grazed pastures at Lansdown, north Queensland, over a 9-year period. Stability was assessed in terms of frequency of appearance and fluctuations in botanical composition. Plants proved short-lived, with a half-life of only 3 months. The majority therefore died in their seedling year, and only 0.03 % survived to the end of the third year. In most years, S. hamata had to re-establish almost entirely from seed. Despite this, S. hamata was a highly persistent legume in the long term owing to its consistently high seed reserves and ready regeneration from seed. In one paddock, for example, it re-established in all quadrats after disappearing from 76% of them the previous year. This long-term persistence was not, however, reflected in yield stability; the content of S. hamata in one paddock changed from 6 to 68% in consecutive years. Low legume yields were recorded when seedlings of S, hamata competed poorly with the annual grasses. Higher yields occurred when more than 20 % of the population comprised perennial S. hamata plants. Retention of the perennial grasses reduced the amplitude of the fluctuations in yields of S. hamata. The perennial grass and S. hamata formed an intimate and stable association. There were only small effects of stocking rate and superphosphate on the persistence of S. hamata, which suggests that the legume is highly tolerant of a wide range of management levels, although more precise management is needed for high animal production.

Satellite derived maps of pasture growth status: association of classification with botanical composition

1997 ◽  
Vol 37 (5) ◽  
pp. 547 ◽  
Author(s):  
P. J. Vickery ◽  
M. J. Hill ◽  
G. E. Donald
Keyword(s):  
Near Infrared ◽  
Perennial Grass ◽  
Vegetation Indices ◽  
Fast Growth ◽  
Perennial Grasses ◽  
Bayesian Probability ◽  
Cumulative Probability ◽  
Botanical Composition ◽  
South Wales ◽  
Native Pastures

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.

Restoration of Exotic Annual Grass-Invaded Rangelands: Importance of Seed Mix Composition

2014 ◽  
Vol 7 (2) ◽  
pp. 247-256 ◽  
Author(s):  
Kirk W. Davies ◽  
Dustin D. Johnson ◽  
Aleta M. Nafus
Keyword(s):  
Species Richness ◽  
Life Forms ◽  
Perennial Grasses ◽  
Annual Grass ◽  
Herbaceous Vegetation ◽  
Plant Life ◽  
Annual Grasses ◽  
Exotic Annual Grass ◽  
Resistance To Invasion ◽  
Plant Life Form

AbstractRestoration of exotic annual grass-invaded rangelands is needed to improve ecosystem function and services. Increasing plant species richness is generally believed to increase resistance to invasion and increase desired vegetation. However, the effects of species richness and individual plant life forms in seed mixes used to restore rangelands invaded by exotic annual grasses have not been investigated. We evaluated the effects of seeding different life forms and increasing species richness in seed mixes seeded after exotic annual grass control to restore desirable vegetation (perennial herbaceous vegetation) and limit exotic annual grasses at two sites in southeastern Oregon. We also investigated the effects of seeding two commonly used perennial grasses individually and together on plant community characteristics. Large perennial grasses, the dominant herbaceous plant life form, were the most important group to seed for increasing perennial herbaceous vegetation cover and density. We did not find evidence that greater seed mix species richness increased perennial herbaceous vegetation or decreased exotic annual grass dominance more than seeding only the dominant species. None of the seed mixes had a significant effect on exotic annual grass cover or density, but the lack of a measured effect may have been caused by low annual grass propagule pressure in the first couple of years after annual grass control and an unusually wet-cool spring in the third year post-seeding. Although our results suggest that seeding only the dominant plant life form will likely maximize plant community productivity and resistance to invasion in exotic annual grass-invaded northern Great Basin arid rangelands, seeding a species rich seed mix may have benefits to higher tropic levels and community stability. Clearly the dominant species are the most prudent to include in seed mixes to restore exotic annual grass-invaded plant communities, especially with finite resources and an increasingly large area in need of restoration.

Correlations between environmental factors, the biomass of exotic annual grasses and the frequency of native perennial grasses

2006 ◽  
Vol 54 (7) ◽  
pp. 655 ◽  
Author(s):  
Tanja I. Lenz ◽  
José M. Facelli
Keyword(s):  
Species Composition ◽  
Soil Fertility ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Annual Rainfall ◽  
Grass Species ◽  
Soil Factors ◽  
Annual Grasses ◽  
Exotic Annual Grasses ◽  
Native Perennial Grass

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.

Pasture management in semi-arid tropical woodlands: effects on herbage yields and botanical composition

1995 ◽  
Vol 35 (6) ◽  
pp. 705 ◽  
Author(s):  
JG McIvor ◽  
CJ Gardener
Keyword(s):  
Perennial Grasses ◽  
Percentage Increase ◽  
Botanical Composition ◽  
Pasture Management ◽  
Management Options ◽  
Stylosanthes Hamata ◽  
Large Yield ◽  
Native Pastures ◽  
Growing Conditions ◽  
Yield Responses

The effects of pasture management options (introduced legumes and grasses, superphosphate, timber treatment, cultivation before sowing, stocking rate) on the yield and botanical composition of pastures were measured from 1982 to 1992 at 2 sites, Hillgrove (extractable phosphorus, 50 mg P/kg) and Cardigan (extractable P, 6 mg/kg), near Charters Towers, northeastern Queensland. Despite generally poor establishment and growing conditions, some sown species (Stylosanthes hamata, S. scabra, Cenchrus ciliaris, Urochloa mosambicensis) established and persisted at both sites. The initial sown grass populations were small but yields increased markedly towards the end of the experiment. There were no yield responses by the native pastures to superphosphate, but the sown pastures responded at Cardigan, although not at Hillgrove. There were large yield responses to tree killing. The percentage increase in herbage yield following tree killing increased as the available water in the soil during the growing season decreased, and was greater at the higher fertility Hillgrove site. Overall, the native pastures were dominated by perennial grasses, but annual grasses and forbs increased on plots with live trees and high stocking rates towards the end of the trial. sown grasses, particularly C. ciliaris, became dominant (and are likely to remain so) at Hillgrove and on plots with superphosphate at Cardigan, especially where the trees were killed. Productive, mixed pastures with reasonable proportions of both grass and legume were maintained under live trees.

The Influence of Recent Grazing Pressure and Landscape Position on Grass Recruitment in a Semi-Arid Woodland of Eastern Australia.

1996 ◽  
Vol 18 (1) ◽  
pp. 3 ◽  
Author(s):  
VJ Anderson ◽  
KC Hodgkinson ◽  
AC Grice
Keyword(s):  
Seedling Emergence ◽  
Perennial Grass ◽  
Soil Surface ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Run Off ◽  
Eastern Australia ◽  
Annual Grasses ◽  
History Of ◽  
Semi Arid

This study examined the effects of previous grazing pressure, position in the landscape and apparent seed trapping capability of soil surface micro-sites on recruitment of the perennial grass Monachather paradoxa (mulga oats) in a semi-arid woodland. Seedling emergence was counted on small plots which had been kept moist for one month. The plots were on bare ground, or at grass tussocks, or at log mounds, sited in the run-off, interception and run-on zones of paddocks that had been grazed for six years at 0.3 and 0.8 sheep equivalent/ha. Few naturally occurring perennial grass seedlings emerged on any of the sites. The level of previous grazing pressure influenced the recruitment of grasses from natural sources as well as from seed of M. paradoxa broadcast on the soil surface; significantly more grass seedlings recruited in paddocks stocked at 0.3 than at 0.8 sheep/ha. Emergence of the sown grass did not differ significantly between the three zones in the landscape, but trends in the data suggest the interception zone may have been the most favourable. Recruitment from in situ grass seed was highest in the mulga grove (run-on) zone. Most seedlings of the sown grass emerged around the bases of existing perennial grass tussocks, but recruitment of volunteer perennial and annual grasses was more evenly distributed between the mulga log-mounds and perennial grass tussocks. It is concluded that very low levels of readily germinable seed of perennial grasses remained in the soil at the end of the drought and that areas with a history of high grazing pressure have less probability of grass recruitment when suitable rain occurs.

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