Propoxycarbazone-Sodium and Imazapic Effects on Downy Brome (Bromus tectorum) and Newly Seeded Perennial Grasses

2011 ◽  
Vol 4 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Gustavo M. Sbatella ◽  
Robert G. Wilson ◽  
Stephen F. Enloe ◽  
Charlie Hicks
Keyword(s):  
Plant Biomass ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Grass Species ◽  
Downy Brome ◽  
Intermediate Wheatgrass ◽  
Psathyrostachys Juncea ◽  
Annual Grasses ◽  
Russian Wildrye

AbstractVigorous stands of perennial grasses can effectively provide long-term control of many invasive plants on rangelands. However, in degraded conditions, successful reestablishment of perennial grasses can be compromised by invasive annual grasses, such as downy brome. Propoxycarbazone-sodium is a selective herbicide currently labeled for downy brome control in small grains, but its potential use on rangelands is unknown. Studies were conducted from 2004 through 2008 at three rangeland sites in Colorado and Nebraska to evaluate downy brome control and perennial grass injury with propoxycarbazone-sodium and imazapic. Propoxycarbazone-sodium provided satisfactory downy brome control with grass injury equal to or less than imazapic when rainfall followed the fall application. A second set of studies was conducted from 2007 to 2008 at Lingle, WY, and Scottsbluff, NE, to determine the plant-back interval and postemergence application response of seven perennial grass species to propoxycarbazone-sodium and imazapic. Grass tolerance to both herbicides was good when applied 90 and 120 d before planting (DBP). However, grass injury increased as plant-back interval decreased. The greatest impact on plant biomass was observed from herbicide applied at planting or after planting. Crested and intermediate wheatgrass (Agropyron cristatumandThinopyrum intermedium) biomass production was not affected when herbicides were applied 90 or 120 DBP. Western wheatgrass (Pascopyrum smithii) and Russian wildrye (Psathyrostachys juncea) showed tolerance to imazapic applied before planting. Smooth brome (Bromus inermis), sheep fescue (Festuca ovina), and orchardgrass (Dactylis glomerata) showed the least amount of tolerance to propoxycarbazone-sodium and imazapic.

Control of Downy Brome (Bromus tectorum) with Herbicides and Perennial Grass Competition

1998 ◽  
Vol 12 (2) ◽  
pp. 391-396 ◽  
Author(s):  
Tom D. Whitson ◽  
David W. Koch
Keyword(s):  
Dry Matter ◽  
Perennial Grass ◽  
Integrated Approach ◽  
Growth Stages ◽  
Downy Brome ◽  
Cool Season ◽  
Growing Seasons ◽  
Annual Grasses ◽  
Russian Wildrye

Long-term control of downy brome with an integrated approach is needed in order to sustain range productivity. Studies were conducted to study the effectiveness of a combination of downy brome control practices. In two studies, glyphosate and paraquat were evaluated at various rates for up to three successive years for control of downy brome in rangeland. A third study evaluated the competitiveness of perennial cool-season grasses against downy brome in the absence of herbicides. Glyphosate, at 0.55 kg/ha, and 0.6 kg/ha paraquat provided selective downy brome control on rangeland when applications were combined with intensive grazing. Downy brome control was greater than 90% following two sequential years of 0.6 kg/ha paraquat at either the two- to eight-leaf stage or bloom stage at both study locations. At one study location, 0.55 kg/ha glyphosate provided 97% control after the first application at both growth stages. In the second study, control averaged greater than 92% following three sequential applications of glyphosate. When perennial cool-season grasses were seeded in the spring following fall tillage (no herbicides) and allowed to establish for three growing seasons, three of the five species were effective in reducing the reestablishment of downy brome. ‘Luna’ pubescent wheatgrass, ‘Hycrest’ crested wheatgrass, ‘Sodar’ streambank wheatgrass, ‘Bozoisky’ Russian wildrye, and ‘Critana’ thickspike wheatgrass controlled 100, 91, 85, 45, and 32% of the downy brome, respectively. Yields of perennial grass dry matter were 1,714, 1,596, 1,135, 900, and 792 kg/ha. Replacing noncompetitive annual grasses with competitive cool-season perennials will provide a longer term solution to a downy brome problem than the use of herbicides alone or with intensive grazing.

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.

The response to moisture and defoliation stresses, and traits for resilience of perennial grasses on the Northern Tablelands of New South Wales, Australia

2003 ◽  
Vol 54 (9) ◽  
pp. 903 ◽  
Author(s):  
S. P. Boschma ◽  
M. J. Hill ◽  
J. M. Scott ◽  
G. G. Rapp
Keyword(s):  
Festuca Arundinacea ◽  
Plant Biomass ◽  
Nitrogen Concentration ◽  
Perennial Grass ◽  
Basal Area ◽  
Perennial Grasses ◽  
Rooting Depth ◽  
Grass Species ◽  
Severe Drought ◽  
Moderate Drought

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.

Short-lived intercrop forages affect long-term yields of alfalfa and wildrye grass mixtures

2002 ◽  
Vol 82 (1) ◽  
pp. 67-74
Author(s):  
A. J. Leyshon ◽  
P. G. Jefferson ◽  
J. Waddington
Keyword(s):  
Medicago Sativa ◽  
Avena Sativa ◽  
Forage Yield ◽  
Perennial Grasses ◽  
Forage Production ◽  
Elymus Trachycaulus ◽  
Psathyrostachys Juncea ◽  
Russian Wildrye ◽  
Slender Wheatgrass

Widely seeded rows (>60 cm) of perennial grasses have exhibited greater long-term yield stability, but allow weed invasion in the first years after establishment. A 9-yr study was conducted at a semiarid site at Swift Current, Saskatchewan, Canada, to determine the effects of intercropping oats (Avena sativa L.) and slender wheatgrass [Elymus trachycaulus (Link) Gould ex Shinners] between rows of Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski], and Altai wildrye [Leymus angustus (Trin) Pilger] seeded in 90-cm spacings either alone or in alternate rows with alfalfa (Medicago sativa L.). Two rows of oats depressed grass forage production in the year following establishment. Slender wheatgrass intercrops reduced grass forage yield and alfalfa forage yield. However, slender wheatgrass contributed to increased total forage yields while it persisted in the mixture. By the fifth year, it had disappeared from the Russian wildrye plots but persisted 2 more years when intercropped with Altai wildrye. Interseeded companion crops, either annual or short-lived perennials, for forage will give short-term yield gains, but long-lived perennial forages may not recover from the competition in the long-term. Key words: Avena sativa, Elymus trachycaulus, Psathyrostachys juncea, Leymus angustus, Medicago sativa, forage yield

Effect of Perennial Grasses on Canada Thistle (Cirsium arvense) Control

1999 ◽  
Vol 13 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Robert G. Wilson ◽  
Stephen D. Kachman
Keyword(s):  
Tall Fescue ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Cirsium Arvense ◽  
Canada Thistle ◽  
Intermediate Wheatgrass ◽  
Western Wheatgrass ◽  
Russian Wildrye ◽  
Grass Establishment ◽  
Grass Biomass

An experiment was conducted near Scottsbluff, NE, to assess three techniques for establishing perennial grasses in pasture sites and to evaluate the effectiveness of five perennial grasses compared with herbicide or mowing for Canada thistle control. Perennial grass density 9 mo after seeding and perennial grass biomass 12 mo after seeding both followed the same trend, indicating that preplant rototilling improved perennial grass establishment. After 3 yr, Canada thistle control was greater than 90% in plots where perennial grasses had been established utilizing preplant rototilling, and competitive grasses were as effective as yearly applications of clopyralid at 0.55 kg/ha for controlling Canada thistle. Averaged across two studies conducted for 3 yr, hybrid wheatgrass, intermediate wheatgrass, Russian wildrye, tall fescue, and western wheatgrass provided 85, 74, 76, 78, and 66% Canada thistle control, respectively.

VECTOR AND HOST RELATIONS OF NORTH AMERICAN WHEAT STRIATE MOSAIC VIRUS

1963 ◽  
Vol 41 (8) ◽  
pp. 1171-1185 ◽  
Author(s):  
J. T. Slykhuis
Keyword(s):  
Mosaic Virus ◽  
Lolium Multiflorum ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Grass Species ◽  
Wheat Varieties ◽  
Wheat Seedlings ◽  
Annual Grasses ◽  
Chloris Gayana ◽  
Test Plants

Wheat striate mosaic virus from wheat in southeastern Saskatchewan was acquired and transmitted by both nymphs and adults of the leafhopper Endria inimica (Say) collected in Ontario. The preinfective period of leafhoppers varied from 4–6 to 22–24 days after they first fed on diseased plants. Records of serial transmission by individual insects varied greatly. Some insects infected most test plants on which they were given 2-day feeds during 20 to 30 days after the preinfective period, but subsequently they transmitted irregularly. Some transmitted virus for only a few days. Others transmitted intermittently for several weeks. None of the insects infected any plants on which they fed later than 72 days after feeding on diseased plants even though some lived another 10 to 20 days. Two of 25 insects became infective after feeds as short as 30 seconds on diseased plants, but the percentages of infective insects increased to more than 90% as acquisition access times were increased to 2 or more days. All insects from some inbred lines became infective after 3 days on diseased plants, but 45% of the descendants of one non-transmitting female failed to become infective. The inoculation threshold period on Ramsey wheat test plants was 15 minutes, but the percentage of test plants infected increased from 15% to 88.8% as the test access times were increased to 4 days. The incubation period of the virus in Ramsey wheat seedlings varied from 6 to more than 28 days.In tests of host reactions, all durum wheat varieties were highly susceptible to the virus. Several of the hard red spring and winter wheat varieties were highly susceptible and a few others were highly resistant or immune, but most were mildly to moderately susceptible. Most varieties of oats and barley and 10 species of wild annual grasses were moderately susceptible. Mild to moderate symptoms also developed on some of the plants in one or more varieties of Zea mays L., Lolium multiflorum Lam., L. perenne L., and Bromus inermis Leyss. Four varieties of rye tested did not develop symptoms, nor did any plants in 13 species of perennial grasses, including Chloris gayana Kunth, which is susceptible to the Australian wheat striate mosaic virus. E. inimica multiplied on wheat and 14 other annual and 21 perennial grass species, many of which are common on the prairies. There was considerable variation in the reactions to the virus of different plants in the variety Ramsey, but there were no inherent variations detected between the virus isolates used for the experiments. The wheat varieties Cappelle-Desprez and Rescue which are highly susceptible to the European type of wheat striate mosaic virus did not become infected with the Canadian isolates tested.Attempts to transmit the European type of wheat striate mosaic virus with E. inimica failed.

Performance of short-lived perennial grasses grown with and without alfalfa at a semiarid location in southern Saskatchewan

2007 ◽  
Vol 87 (1) ◽  
pp. 59-65 ◽  
Author(s):  
P. G. Jefferson ◽  
R. P. Zentner ◽  
F. Selles ◽  
R. Lemke
Keyword(s):  
Perennial Grass ◽  
Forage Yield ◽  
Perennial Grasses ◽  
Grass Species ◽  
Semiarid Region ◽  
Canadian Prairies ◽  
Intermediate Wheatgrass ◽  
Elymus Trachycaulus ◽  
Short Rotation ◽  
Slender Wheatgrass

Tyically, crop rotations in the semiarid region of the Canadian prairies do not include perennial forages because forage termination produces negative effects on subsequent annual crops. Three short-lived perennial grass species, Dahurian wildrye grass (Elymus dahuricus Turcz. Ex Griseb), intermediate wheatgrass [Elytrigia intermedia (Host) Nevski] and slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners), were compared for their forage productivity and persistence as short duration (3 yr) forage stands, either in a mixture with alfalfa (Medicago sativa L.) or in monoculture, in three trials at Swift Current, Saskatchewan. Intermediate wheatgrass produced 29 and 22% more forage and was more persistent than Dahurian wildrye or slender wheatgrass, respectively. In alfalfa mixtures, however, the grasses produced similar forage yield in two of three trials. Intermediate wheatgrass was more persistent in mixtures but yield compensation by alfalfa grown with Dahurian wildrye and slender wheatgrass produced similar total forage yield as these grass stands thinned during the third year of each trial. Intermediate wheatgrass and alfalfa mixtures could be utilized for short rotation forage stands in high-input crop sequences where stand termination is achieved with herbicides. Dahurian wildrye and alfalfa mixture has the best potential for short-rotation forages in organic crop systems of this region because it would require less tillage to terminate the stand. Key words: Crop rotation, forage yield

Role of Size and Nitrogen in Competition between Annual and Perennial Grasses

2013 ◽  
Vol 6 (1) ◽  
pp. 87-98 ◽  
Author(s):  
L. Noelle Orloff ◽  
Jane M. Mangold ◽  
Fabian D. Menalled
Keyword(s):  
Life Histories ◽  
Perennial Grass ◽  
Leaf Size ◽  
Perennial Grasses ◽  
Downy Brome ◽  
Greenhouse Study ◽  
Bluebunch Wheatgrass ◽  
Annual Grasses ◽  
Exotic Annual Grass ◽  
N Enrichment

AbstractDiffering life histories contribute to difficulties establishing perennial grasses on lands dominated by exotic annual grasses. In a greenhouse study, we investigated to what extent allowing the perennial grass bluebunch wheatgrass to emerge before the exotic annual grass downy brome would increase its competitive ability and whether modifying nitrogen (N) would affect competition. We conducted an addition-series factorial experiment. In three cohort treatments, the two species were seeded concurrently or bluebunch wheatgrass was at the two- or four-leaf stage when downy brome was planted. N treatments were low (ambient) or high (N added to maintain 10 mg kg−1 [0.1286 oz lb−1]). Larger bluebunch wheatgrass avoided suppression by downy brome regardless of N. Under concurrent sowing, doubling downy brome density decreased bluebunch wheatgrass biomass by 22.6% ± 2.38 SE. In contrast, when bluebunch wheatgrass had a four-leaf size advantage, the same increase in downy brome density decreased bluebunch wheatgrass biomass by 4.14% ± 2.31. Larger bluebunch wheatgrass also suppressed downy brome more effectively, but N enrichment decreased the suppressive ability of bluebunch wheatgrass.

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.

Spring Glyphosate Application for Selective Control of Downy Brome (Bromus tectorumL.) on Great Basin Rangelands

2016 ◽  
Vol 30 (1) ◽  
pp. 297-302 ◽  
Author(s):  
Christo Morris ◽  
Lesley R. Morris ◽  
Cheryl Surface
Keyword(s):  
Great Basin ◽  
Perennial Grass ◽  
Early Spring ◽  
Perennial Grasses ◽  
First Year ◽  
Grass Cover ◽  
Perennial Species ◽  
Downy Brome ◽  
Alternative Approach ◽  
Annual Grasses

Downy brome has converted millions of hectares of Great Basin rangelands from shrubland to annual grass-dominated systems. Methods for removing downy brome from sites that already have perennial grasses established are especially needed because of the difficulty in re-establishing perennial species. In this study, early spring applications of glyphosate alone and glyphosate plus imazapic were monitored for 2 yr. Cover of downy brome was reduced from 45 to 10% by spring application of glyphosate alone and to approximately 1% with the addition of imazapic. Perennial grass cover was not affected by the spring application of glyphosate. The addition of imazapic reduced perennial grass cover in the first year; however, it recovered by the second year. The selective response to glyphosate may be due to differences in growth stage or dormancy characteristics between annual and perennial species. Our findings suggest spring application of glyphosate may provide an alternative approach for managing annual grasses on Great Basin rangelands.

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