Differential translocation of paraquat in paraquat-resistant populations of Hordeum leporinum

Weed Research ◽  
2005 ◽  
Vol 45 (4) ◽  
pp. 289-295 ◽  
Author(s):  
C PRESTON ◽  
C J SOAR ◽  
I HIDAYAT ◽  
K M GREENFIELD ◽  
S B POWLES
Keyword(s):  
Hordeum Leporinum

Growth and ignitability of annual pastures in a Mediterranean environment. 2. Ignitability of swards of various annual species

1970 ◽  
Vol 10 (42) ◽  
pp. 76 ◽  
Author(s):  
RT Parrott ◽  
CM Donald
Keyword(s):  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Individual Species ◽  
Atmospheric Conditions ◽  
Annual Species ◽  
Lolium Rigidum ◽  
Mediterranean Environment ◽  
Desiccation Process ◽  
Hordeum Leporinum ◽  
Pasture Plants

A study was conducted at Adelaide of the ignitability of monospecific swards of four Mediterranean annual pasture plants under windless conditions throughout the normal field desiccation of the swards in the spring. For any individual species the ignitability depended almost wholly on the percentage of water or the very closely correlated percentage of dead herbage. Atmospheric conditions had no measurable influence on ignitability during desiccation. Trifolium subterraneum was much less ignitable at any particular level of moisture content than were the grasses. Lolium rigidum was more inflammable early in the desiccation process than was Hordeum leporinum of equal water content, presumably due to the greater continuity of dry leaf; but H. leporinum was ignitable much earlier in the spring because it matured and dried sooner than did L. rigidum. In the case of the grasses, only those firebrands that fell to or near the soil surface started a fire, whereas the more compact sward of T. subterraneum, when sufficiently dry, lit readily at the upper surface.

Plant factors influencing the nutritive value of some temperate annual pasture species

1973 ◽  
Vol 13 (63) ◽  
pp. 404 ◽  
Author(s):  
JG McIvor ◽  
DF Smith
Keyword(s):  
Nutritive Value ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growth Cycle ◽  
Matter Content ◽  
In Vitro Digestibility ◽  
Dry Matter Content ◽  
Hordeum Leporinum ◽  
Brome Grass

Changes in herbage production, dry matter content, nitrogen content and in vitro digestibility of two sown species-subterranean clover (Trifolium subterraneum) and annual ryegrass (Lolium rigidum) - and five common volunteer species-capeweed (Arctotheca calendula), musky crowfoot (Erodium moschatum), barley grass (Hordeum leporinum), ripgut brome grass (Bromus rigidus) and soft brome grass (Bromus mollis)-were measured throughout their growth cycle. The volunteer species compared favourably with the sown species for these measurements and should be capable of providing nutritious grazing for animals.

The growth of barley grass (Hordeum leporinum) in annual pasture. 3. Some factors affecting balance with subterranean clover (Trifolium subterraneum)

1968 ◽  
Vol 8 (35) ◽  
pp. 702 ◽  
Author(s):  
DF Smith
Keyword(s):  
Soil Nitrogen ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Nitrogen Addition ◽  
The Other ◽  
Early Start ◽  
Factors Affecting ◽  
Two Factors ◽  
Hordeum Leporinum

Mixed swards of barley grass (Hordeum leporinum) and subterranean clover (Trifolium subterraneum) of two densities were grown at two levels of nitrogen. Growth was started at two different times mid- April and mid-May-and at each time half the plots were subjected to moisture stress. The swards were harvested after nine weeks of growth. The survival of clover plants was reduced by an early start, moisture stress and nitrogen addition : much more so than barley grass. The root : shoot ratios of both species were calculated ; both showed some sensitivity to the time of break and moisture stress, and the grass was also affected by the other two factors. Total sward production and the ratios of clover to grass varied widely Grass daminance was favoured by moisture stress or a late break, and both of these factors tended to override the effect of higher soil nitrogen in determining clover-grass balance. Total sward production more dependent on density than any other factor, especially with the later start. Higher nitrogen was effective in boosting production only if the break was early and there was no moisture stress.

Herbicides for the selective control of barley grass in irrigated clover pastures

1963 ◽  
Vol 3 (8) ◽  
pp. 35 ◽  
Author(s):  
VR Squires
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Subterranean Clover ◽  
Severe Damage ◽  
Complete Control ◽  
Selective Control ◽  
Hordeum Leporinum ◽  
Trifolium Repens L ◽  
Clover Pasture ◽  
Slight Damage

Three herbicides, 2,2- DPA (2,2-dichloropropzonzc acid), diquat dibromide (9, l0-dihydro-8a, 10a-dizonia phenanthrene dibromide) and paraqmt di (methyl sulphate) (1,l-dimethl-4,4,-bipryridylium di (methyl sulphate) ) were tested with a view to controlling barley grass (Hordeum leporinum Link) in clover pastures. The tolerance of white clover (Trifolium repens L.) and subterranean clover (T. subterraneum L.) to sodium 2,2-DPA was determined. 2,2-DPA caused severe damage to subterranean clover (resulting in the loss of one season's production) and slight damage to white clover at a rate which controlled the grass-2 lb an acre acid equivalents. Diquat dibromide applied at 2 lb an acre (active cation) in mid winter gave complete control of barley grass in a subterranean clover pasture. Springfields of clover on treated plots were double those of the unseated control. Paraquat di (methyl sulphate) gave satisfactory control of barley, grass at 0.5 lb an acre, as an early post emergence spray, with no increase in subterranean clover yields, At the 1 lb an acre rate barley grass control was complete.

Effect of fertilizer nitrogen, stocking rate and autumn deferment of grazing in association with hay cutting on the root structure of annual pasture species

1976 ◽  
Vol 16 (78) ◽  
pp. 110 ◽  
Author(s):  
JJ Doyle ◽  
MJ Sharkey
Keyword(s):  
Nitrogen Fertilizer ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Grazing Pressure ◽  
Stocking Rate ◽  
Root Structure ◽  
Root Branching ◽  
Grass Roots ◽  
Hordeum Leporinum ◽  
Main Components

Length, weight, branching and chemical composition of roots of barley grass (Hordeum leporinum) and subterranean clover, (Trifolium subterraneum), the main components of a non-irrigated pasture were measured in the fourth year of an experiment on pastures grazed by Corriedale wethers. The grazing treatments were in a factorial design (2 x 2 x 3) replicated three times, with three stocking rates, two levels of nitrogen fertilizer and two methods of management. Grass and clover density was reduced progressively as stocking rate was increased from 10 to 12 to 17 wethers ha-1 but the surviving plants at maturity had vigorous root systems. This performance of annual species contrasts with that of perennial pasture species where root development and root branching may be expected to decline with increase in grazing pressure. Applications of nitrogen fertilizer annually at rates of 0 or 67 kg ha-1 had little effect on density of grasses or clovers but clover roots were lighter and had fewer rhizobia nodules where nitrogen fertilizer had been applied. The management of pasture by deferment of grazing during regeneration was beneficial to clover plants in that their root structure was larger at maturity; similar effects were not evident in grass roots.

Seed dormancy release in three common pasture grasses from a Mediterranean-type environment under contrasting conditions

1999 ◽  
Vol 39 (2) ◽  
pp. 143 ◽  
Author(s):  
T. P. Bolger ◽  
R. Chapman ◽  
I. F. Le Coultre
Keyword(s):  
Seed Bank ◽  
Dormancy Release ◽  
Annual Ryegrass ◽  
Bromus Diandrus ◽  
Pasture Legumes ◽  
Pasture Grasses ◽  
Hordeum Leporinum ◽  
Winter Annuals ◽  
Brome Grass ◽  
Summer Rain

Pastures in the Mediterranean region of Australia are typically comprised of a mixture of winter annuals, including grasses and legumes, which utilise a seed bank to survive the long, dry summer. The risk of out-of-season summer rain requires species from such environments to adopt appropriate strategies to protect their seed banks. The seed bank strategies of the grasses from these environments have, so far, received little attention. We conducted an experiment to observe the dormancy release characteristics of 3 grasses common to these environments when stored under contrasting thermal regimes. The grasses studied were great brome grass (Bromus diandrus Roth), annual ryegrass (Lolium rigidum Gaud.), and barley grass (Hordeum leporinum Link). The different species displayed contrasting dormancy release characteristics over the summer. Two of the species examined (great brome grass and annual ryegrass) displayed relatively late release from dormancy which gave high levels of protection from false breaks. The other (barley grass) displayed earlier release from dormancy which would enable it to better exploit earlier true breaks but make it more sensitive to false breaks. Unlike pasture legumes, high and fluctuating temperatures were not necessary for the seeds of these grasses to become germinable. In fact, exposure to high temperatures appeared more likely to suppress release from dormancy.

A Biotype of Hare Barley (Hordeum leporinum) Resistant to Paraquat and Diquat

Weed Science ◽  
1991 ◽  
Vol 39 (2) ◽  
pp. 159-162 ◽  
Author(s):  
Edwin S. Tucker ◽  
Stephen B. Powles
Keyword(s):  
Dry Matter ◽  
Normal Rate ◽  
Dry Matter Production ◽  
Annual Grass ◽  
Herbicide Application ◽  
Matter Production ◽  
Alfalfa Field ◽  
History Of ◽  
Hordeum Leporinum ◽  
Grass Weed

A biotype of the annual grass weed hare barley infesting an alfalfa field with a 24-yr history of the use of the bipyridylium herbicides paraquat and diquat, was investigated for resistance to these herbicides. Rates of up to 800 g ai ha–1of each herbicide caused no mortality in the hare barley plants from this field. The same species, collected from an adjacent pasture field with no history of bipyridylium herbicide application, exhibited LD50'sof 57 and 160 g ai ha–1for paraquat and diquat, respectively. Tiller numbers and dry matter production in the biotype from the alfalfa field were not affected by the normal rate recommended for both herbicides. These results clearly show that hare barley from the alfalfa field is resistant to paraquat and diquat. Both biotypes were equally sensitive to fluazifop, glyphosate, and sethoxydim.

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