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.

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.

scholarly journals Invasive Grasses Increase Nitrogen Availability in California Grassland Soils

2010 ◽  
Vol 3 (1) ◽  
pp. 40-47 ◽  
Author(s):  
Sophie S. Parker ◽  
Joshua P. Schimel
Keyword(s):  
Nitrogen Availability ◽  
Perennial Grass ◽  
N Cycling ◽  
Rooting Depth ◽  
Grass Species ◽  
Annual Grass ◽  
Annual Grasses ◽  
California Grassland ◽  
Pool Sizes ◽  
Native Perennial Grass

AbstractAs Europeans colonized California, they introduced annual grasses from the Mediterranean Basin. These exotic annual grasses eventually invaded grasslands throughout the state, some of which were once dominated by native perennial grass species. Annual grasses differ from perennials in their phenology, longevity, rooting depth, litter chemistry, and interaction with the microbial community. As these traits may influence plant nitrogen (N) use, it is likely that the invasion by annual species resulted in changes in the availability and cycling of N in California grassland systems. We addressed the question of how invasive annual grasses influence rates of N cycling by measuring N pool sizes and rates of net and gross mineralization and nitrification, gross immobilization, and the denitrification potential of soils from experimentally planted annual and perennial-dominated grasslands. With an increase in annual grass cover, we saw increases in ammonium (NH4+) pool sizes and rates of N mineralization, nitrification, and denitrification in soils. These differences in N status suggest that N cycling in California grasslands was altered at sites where native perennial bunchgrasses were invaded by nonnative annual grasses. One consequence of annual grass invasion may be a legacy of NH4+-enriched soils that hinder the reestablishment of native perennial grass species.

scholarly journals Native Perennial Grasses in Highway Medians: Pre- and Postplant Techniques for Establishment in a Mediterranean Climate

2008 ◽  
Vol 1 (4) ◽  
pp. 368-375
Author(s):  
Stephen L. Young ◽  
Victor P. Claassen
Keyword(s):  
Plant Density ◽  
Perennial Grass ◽  
Field Studies ◽  
Perennial Grasses ◽  
Species Selection ◽  
Grass Species ◽  
Native Plant ◽  
Grass Establishment ◽  
Grass Growth ◽  
Native Perennial Grass

AbstractWithin highway rights-of-way, native perennial grasses provide desirable services to support natural and human constructed ecosystems. However, native perennial grass establishment in annual grass dominated roadsides of semiarid and Mediterranean climates of the western United States requires specific cultural and chemical management treatments to control weeds. In 2004, field studies were conducted in Sacramento Valley, California to determine the effect of herbicide, disc cultivation, and species selection on native perennial grass establishment and annual weed persistence. Perennial grass species mixes common to drier and wetter upland areas in northern California were drill seeded at two sites (I-5 North and I-5 South) that had been burned in 2003 and received weed control (i.e., herbicide, cultivation, mowing) in spring 2004. Herbicides were the most important treatments for native perennial grass establishment and weed reduction. Native perennial grass species persistence was largely unaffected by cultivation or native plant accessions at these sites. Native perennial grass density increased at I-5 North in the second year of growth (2006) resulting in a plant density totaled across all herbicide regimes of 3.9 plants m−1 compared to 2.5 plants m−1 at I-5 South. Vigorous native perennial grass growth in the more fertile and less droughty soils of I-5 North helped to limit annual weeds through competition, which is anticipated to reduce the need for chemical and mechanical control in years following early establishment.

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.

The germinable soil seedbank of Eucalyptus victrix grassy woodlands at Roy Hill station, Pilbara district, Western Australia

2004 ◽  
Vol 26 (1) ◽  
pp. 17 ◽  
Author(s):  
R. A. Graham ◽  
S. K. Florentine ◽  
J. E. D. Fox ◽  
T. M. Luong
Keyword(s):  
Species Composition ◽  
Western Australia ◽  
Perennial Grass ◽  
Summer Rainfall ◽  
Distribution Patterns ◽  
Grass Species ◽  
Surface Areas ◽  
Hill Station ◽  
Soil Seedbank ◽  
Germinable Seed

The paper reports soil seedbank species composition, of Eucalyptus victrix grassy woodlands, of the upper Fortescue River in the Pilbara District, Western Australia. In this study, our objectives were to investigate germinable soil seedbanks and species composition in response to three simulated seasons, using emergence. Variation in seed density from three depths was tested. Four field sites were sampled. Thirty samples were collected in late spring, after seed rain and before summer rainfall. From each sample spot, three soil depths (surface, 1–5, and 6–10 cm) were segregated from beneath surface areas of 100 cm2. Samples were later incubated in a glasshouse to simulate three different seasonal conditions (autumn, winter and spring). Germinating seedlings were recorded on emergence and grown until identified. Forty-one species germinated, comprising 11 grasses (7 annuals and 4 perennials), 25 annual herbs and 5 perennial herbs. Distribution patterns of germinable seed in both the important annual grass Eragrostis japonica and the perennial Eragrostis setifolia (a preferred cattle fodder species), suggest that seedbank accumulation differs among species and between sites. In part, this may be associated with the absence of grazing. Species with most total germinable seed were E. japonica (Poaceae; 603/m2), and the annual herbs Calotis multicaulis (Asteraceae; 346/m2), and Mimulus gracilis (Scrophulariaceae; 168/m2). Perennial grass seed was sparse. Spring simulation gave most germination (1059), followed by autumn (892) and winter (376) sets. Greatest species diversity was produced from the spring simulation (33 species), followed by autumn (26), and winter (22). Of the total germination, 92% came from 17 species that were represented in all three simulations. Of the 1227 grass seedlings counted, most were recruited from the surface soil (735), followed by the 5 (310) and 10 (182) cm depths. Marginally more grass seedlings germinated from the spring simulation (558) than the autumn set (523). Only 11.9% of grass germinants came from the winter simulation. All grass species recruited from the soil seedbanks had a C4 photosynthetic pathway. Except for Cenchrus ciliaris all grass species are native to Australia. Of the four sites sampled, one fenced to exclude cattle five years earlier had significantly more germination than the three unfenced sites. Seedbank sampling produced several new records for plants in the areas sampled.

scholarly journals The search for alternative temperate perennial pasture species for low to medium rainfall environments in Tasmania

2016 ◽  
Vol 16 ◽  
pp. 275-279
Author(s):  
E.J. Hall ◽  
R. Reid ◽  
B. Clark ◽  
R. Dent
Keyword(s):  
Perennial Grass ◽  
Dactylis Glomerata ◽  
Red Clover ◽  
Perennial Grasses ◽  
Grass Species ◽  
Sheep Grazing ◽  
Cool Temperate ◽  
Perennial Legume ◽  
Perennial Legumes ◽  
Pasture Plants

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

scholarly journals Scientific bases of the humus stabilization in ordinary chernozem in Russia

2019 ◽  
Vol 52 (1) ◽  
pp. 113
Author(s):  
Oleg Goryanin ◽  
Anatoly Chichkin ◽  
Baurzhan Dzhangabaev ◽  
Elena Shcherbinina
Keyword(s):  
Soil Fertility ◽  
Humus Content ◽  
Perennial Grasses ◽  
Crop Rotations ◽  
Organic Fertilizers ◽  
Annual Rainfall ◽  
Ordinary Chernozem ◽  
Mineral Fertilizers ◽  
Plant Residues ◽  
Middle Volga Region

<p>The influence of long-term use of mineral and organic fertilizers, crop rotations, plant residues, soil treatment systems on humus content of common chernozems and stabilization of productivity of field crops in the arid conditions of the Middle Volga region is considered on the example of researches in the Samara area. The zone climate of field experiments is characterized as extremely continental. The sum of the active temperatures (above 10°C) is 2,800-3,000°C. The average annual rainfall is 454.1 mm with fluctuations over the years from 187.5 mm to 704.6 mm. At some years, precipitation does not happen within a month or more. Hydrothermal index in May-August is 0,7, the duration of the frost-free period is 149 days. If the humus content in the region is 4.35-4.52%, then, it is necessary to introduce 6.7-8.0 t/ha of manure per year to maintain the balance of the deficit. The introduction of biological methods for the conservation and reproduction of soil fertility (green fertilizers, perennial grasses, straw as fertilizer) reduces the loss of humus by 0.15-0.24 t/ha. This makes it possible to increase the payback of mineral fertilizers, which must be taken into account when developing fertility reproduction systems for soils. In the variants with minimal and differentiated cultivation of the soil during crop rotation in 30 years of the study, the loss of humus in the 0-30 cm layer decreased by 0.04 - 0.73% (43-789 kg per year with maximum values in the combination of direct seeding of spring crops with deep loosening for a number of crop rotations is 4.14%, significantly exceeding the control (by 0.54%). The decrease in soil fertility in the variants with constant plowing and minimal tillage contributed to an increase in the conjugation of productivity of crops with humus. Based on the research, in order to preserve the fertility of the soil of ordinary chernozem, it is necessary to use green fertilizer, leguminous perennial grasses. In the regional rotations of crop production, new generation technologies are recommended, the basis of which is differentiated tillage with the use of crushed straw as fertilizer.</p>

scholarly journals Caucasian clover was more productive than white clover in grass mixtures under drought conditions

2000 ◽  
pp. 183-188 ◽  
Author(s):  
A.D. Black ◽  
R.J. Lucas
Keyword(s):  
White Clover ◽  
Festuca Arundinacea ◽  
Perennial Grass ◽  
Moisture Stress ◽  
Annual Rainfall ◽  
Grass Species ◽  
Pasture Production ◽  
Trifolium Ambiguum ◽  
Dry Conditions ◽  
Schedonorus Phoenix

This experiment compared the productivity of caucasian or white clover when established with five perennial grass species over 6 years in a dry lowland environment. Hexaploid 'Endura' caucasian clover or 'Grasslands Demand' white clover were sown in December 1994 with high endophyte 'Yatsyn' perennial ryegrass, 'Grasslands Wana' cocksfoot, 'Grasslands Advance' tall fescue, 'Grasslands Gala' grazing brome, or 'Grasslands Maru' phalaris into a deep, fertile silt loam. Initial establishment of clovers was poor with ryegrass and grazing brome. Some volunteer white clover established in all 10 treatments. After the first 14 months, no irrigation was applied over the following 4 years. Sheep grazed plots about six times each year. The legume cover in 15-month-old pastures was higher when sown with white clover (29%) than caucasian clover (21%) but dry conditions during 1997/1998 (60% of 680 mm mean annual rainfall) and 1998/1999 (66% of mean rainfall) decreased the percentage of legume in white clover pastures. In February 1998 and March 1999, legume contributed 37% and 21% of the dry matter (DM) in caucasian clover pastures, but only 4% and 1% in pastures sown with white clover. Rainfall during the sixth season (1999/2000) was more favourable (111% of mean rainfall). Total DM production from July 1999 to June 2000 was 10.0 t DM/ha from caucasian clover pastures and 8.7 t DM/ha from pastures sown with white clover. The mean proportion of legume in white clover pastures ranged from 9% when sown with ryegrass and phalaris to 1% with cocksfoot. In contrast, mean caucasian clover legume contents were similar across all grass treatments at 20%, but reached 46% with cocksfoot during summer. It was concluded that caucasian clover is more tolerant of summer moisture stress than white clover when in association with perennial grass species. Keywords: botanical composition, Bromus stamineus, Dactylis glomerata, legume content, Lolium perenne, moisture stress, pasture production, Phalaris aquatica, Schedonorus phoenix syn. Festuca arundinacea, Trifolium ambiguum, T. repens

Indirect effects of an invasive annual grass on seed fates of two native perennial grass species

Oecologia ◽  
2014 ◽  
Vol 174 (4) ◽  
pp. 1401-1413 ◽  
Author(s):  
Susan E. Meyer ◽  
Katherine T. Merrill ◽  
Phil S. Allen ◽  
Julie Beckstead ◽  
Anna S. Norte
Keyword(s):  
Indirect Effects ◽  
Perennial Grass ◽  
Grass Species ◽  
Annual Grass ◽  
Seed Fates ◽  
Native Perennial Grass

scholarly journals Integrated Management of Perennial Pepperweed (Lepidium latifolium)

2008 ◽  
Vol 1 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Rob G. Wilson ◽  
Debra Boelk ◽  
Guy B. Kyser ◽  
Joseph M. DiTomaso
Keyword(s):  
Integrated Management ◽  
Perennial Grass ◽  
Management Strategies ◽  
Site Preparation ◽  
Perennial Grasses ◽  
Flower Bud ◽  
No Till ◽  
Wide Range ◽  
Grass Establishment ◽  
Native Perennial Grass

AbstractPerennial pepperweed is invasive throughout California. It thrives in a wide range of environments and is a common weed in floodplains, pastures, wetlands, and roadsides. In disturbed areas, perennial pepperweed rapidly forms monotypic stands with a thick litter layer. These infestations not only out-compete other vegetation, but prevent re-establishment of desirable species even after perennial pepperweed control. This experiment examined integrated management strategies with the goal of maximizing perennial pepperweed control and establishment of desirable native vegetation. The experiment was conducted at two sites in Lassen County, CA. Both sites were heavily infested with perennial pepperweed and lacked competing vegetation. The experimental design was a split-split-randomized block with four replications. Site preparation treatments included winter burning, summer and fall mowing, winter grazing, and fall disking. These treatments were designed to remove thatch to facilitate herbicide application and reseeding of desirable perennial grasses. Herbicide treatments included chlorsulfuron, 2,4-D, or glyphosate applied at the flower bud stage. Revegetation treatments included no seeding and no-till seeding of native perennial grasses. Most site preparation plus herbicide combinations reduced perennial pepperweed cover > 85% compared to the untreated control, although treatment efficacy was variable between sites and years. Burning, grazing, mowing, or disking in combination with herbicide treatment and no-till seeding was necessary for successful native perennial grass establishment. Burning or mowing with yearly 2,4-D applications for 3 yr gave the best combination of perennial pepperweed control and native grass establishment. Chlorsulfuron caused chlorosis and stunting to western wheatgrass, basin wildrye, and beardless wildrye at both sites when applied the spring before seeding. No treatment offered complete weed control, suggesting follow-up spot herbicide applications are needed for long-term perennial pepperweed suppression. These results provide several successful integrated strategies for control of perennial pepperweed and revegetation to a desired native perennial grass community.

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