The germination and establishment of two annual pasture grasses (Hordeum leporinum Link and Lolium rigidum Gaud.)

1973 ◽  
Vol 24 (1) ◽  
pp. 1 ◽  
Author(s):  
PS Cocks ◽  
CM Donald
Keyword(s):  
High Temperatures ◽  
Mediterranean Region ◽  
Soil Surface ◽  
Lolium Rigidum ◽  
High Moisture ◽  
Pasture Grasses ◽  
Annual Grasses ◽  
Similar Range ◽  
Hordeum Leporinum ◽  
Pasture Plants

The germination and establishment of Hordeum lepovinum Link and Lolium rigidum Gaud., two Mediterranean annual grasses, were studied under controlled conditions. Results were related to the ecology of these species as pasture plants in southern Australia. Seeds of the two species germinated over a similar range of constant temperatures (8-30�C); Hordeum germinated much more rapidly than Lolium at all temperatures. Lolium has a marked requirement for alternating temperatures for maximum germination, while Hovdeum has a weak or nil requirement. Both species withstood prolonged wetting at high temperatures without germinating or losing all viability. Prior soaking and redrying before germination increased the rate of germination of both species. Light rains which fall before the first germinating autumn rains usually wet the seed only for short periods and this further increases the advantage of Hordeum over Lolium in rate of germination. Hordeum germinated and established much more readily on the soil surface than did Lolium, even though Lolium absorbed water more rapidly. The success of Houdeum was due both to its rapidity of germination, which allowed it to establish before the soil surface dried out, and to its ability to germinate at high moisture tensions. Because of these features Hordeum leporinum has the potential to germinate earlier, more rapidly, and more freely than Lolium rigidum in the autumn of the Mediterranean region of southern Australia.

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.

Response to nitrogen of three annual grasses

1974 ◽  
Vol 14 (67) ◽  
pp. 167 ◽  
Author(s):  
PS Cocks
Keyword(s):  
Nitrogen Uptake ◽  
Dry Weight ◽  
Low Density ◽  
Lolium Rigidum ◽  
Nitrogen Response ◽  
Harvest Dates ◽  
Wide Range ◽  
Annual Grasses ◽  
Hordeum Leporinum ◽  
Better Than

The responses of three annual grasses (Lolium rigidum, Vulpia myuros, and Hordeum leporinum) to nitrogen fertilizer were studied at three densities. Total herbage and nitrogen uptake were measured at four harvest dates. The response of the three grasses to nitrogen depended on their density. At low density both Lolium and Hordeum had greater dry weight increase than Vulpia, but at high density Vulpia responded as well as Lolium and better than Hordeum. By comparing the nitrogen responses at similar amounts of available herbage it was seen that, over a wide range of availability, both Lolium and Vulpia had greater absolute response than Hordeum. It was concluded that nitrogen response would probably be greatest on swards of Lolium or Vulpia that have a particular amount of available herbage.

The influence of density and nitrogen on the outcome of competition between two annual pasture grasses (Hordeum leporinum Link and Lolium rigidum Gaud.)

1974 ◽  
Vol 25 (2) ◽  
pp. 247 ◽  
Author(s):  
PS Cocks
Keyword(s):  
Soil Nitrogen ◽  
Competitive Ability ◽  
Total Density ◽  
Lolium Rigidum ◽  
High Nitrogen ◽  
Original Hypothesis ◽  
Pasture Grasses ◽  
Hordeum Leporinum ◽  
Low Nitrogen

The hypothesis that the outcome of competition between Hordeum leporinum Link and Lolium rigidum Gaud. depended predominantly on the density of Hordeum was tested in two experiments. In the first experiment it was postulated that increasing the density of Hordeum increased its competitive ability; in the second experiment the interaction between soil nitrogen and density was studied. Under the conditions of the first experiment the hypothesis was shown to be true. The competitive ability of Hordeum was closely related to its density, and neither the density of Lolium nor the total density had a significant effect. Hordeum was most competitive when its density was highest. The second experiment showed that soil nitrogen was an important modifying factor. At low nitrogen Hordeum was the successful competitor, but its competitive ability decreased with increase in its density. At high nitrogen Lolium became the successful competitor, although the effect of Hordeum density was similar to that in experiment 1. At the lower levels of nitrogen the density of Lolium also affected the outcome of competition, but its effect was never as great as that of the density of Hordeum. The results are explained in terms of the original hypothesis and of the different abilities of the two species to absorb soil nitrogen.

The early vegetative growth of two annual pasture grasses (Hordeum leporinum Link and Lolium rigidum Gaud.)

1973 ◽  
Vol 24 (1) ◽  
pp. 11 ◽  
Author(s):  
PS Cocks ◽  
CM Donald
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Vegetative Growth ◽  
Root Weight ◽  
Lolium Rigidum ◽  
Pasture Production ◽  
Relative Growth ◽  
Pasture Grasses ◽  
Seedling Growth Rate ◽  
Hordeum Leporinum

The early vegetative growth of Houdeum Iepouinum and Lolium rigidum was studied at three temperatures in a controlled environment cabinet. The seedling growth rate in each species was much more rapid during the period of endosperm availability than after cndospcrm exhaustion. At the temperatures tested (10, 17, and 24�C) the relative growth rate of Lolium was greater than that of Houdeum, with a relatively slight difference at 10 and 24�, but with a considerable difference at 17�. In spite of the superior relative growth rate of Lolium, seedlings of Houdeum were, for a considerable period following emergence, larger in terms of total weight, leaf area, root weight, root depth, and plant height because of the greater seed size. The length of this period of greater size depended on the temperature, being least (c. 26 days) at 17�C, when the advantage of Lolium was greatest. The implications of these findings in pasture production in southern Australia, and especially in the competitive relationships of Hordeum and Lolium, are described.

Comparative germination patterns of annual grasses in north-eastern Victoria

1970 ◽  
Vol 10 (45) ◽  
pp. 401 ◽  
Author(s):  
AA McGowan
Keyword(s):  
Seasonal Distribution ◽  
Cereal Crops ◽  
Late Winter ◽  
Annual Grass ◽  
Lolium Rigidum ◽  
Winter Cereal ◽  
North Eastern ◽  
Annual Grasses ◽  
Hordeum Leporinum ◽  
Bromus Mollis

The seasonal distribution of germination of Lolium rigidum, Vulpa bromoides, Hordeum leporinum and Bromus mollis was measured under field conditions. The study was conducted in north-eastern Victoria from February to August in 1966 and 1967. Although 49-97 per cent of seed of all species had germinated by the end of April, the proportions of Lolium and Volpia that emerged after April (36 and 45 per cent respectively) were greater than the analogous proportions of Hordeum and Bromus (18 and 13 per cent respectively). These differences in germination pattern are considered to be of potential importance in explaining the incidence of annual grass weeds in winter cereal crops, but of little significance explaining the persistence of these grasses in grazed pastures. Less th-an one per cent of the original seeds remained viable on or in the soil by late winter.

Ascochyta rabiei. [Descriptions of Fungi and Bacteria].

1972 ◽  
Author(s):  
E. Punithalingam
Keyword(s):  
Cicer Arietinum ◽  
Geographical Distribution ◽  
Mediterranean Region ◽  
Soil Surface ◽  
Ascochyta Rabiei ◽  
Seed Formation ◽  
Chick Pea ◽  
Whole Plant ◽  
Water Splash ◽  
Seed Infestation

Abstract A description is provided for Ascochyta rabiei. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Cicer arietinum. DISEASE: Blight of gor chick pea (Cicer arietinum), attacks all above-ground parts of the plant; circular lesions on leaves and pods and elongate ones on petioles and stems. The pycnidia form in concentric areas on these lesions and in severe attacks the whole plant is killed. GEOGRAPHICAL DISTRIBUTION: Restricted to the Mediterranean region, S.E. Europe, S.W. Asia and also reported from Tanzania (CMI Map 151, ed. 2, 1966). Additional areas not yet mapped are: Lebanon, Turkey, USSR (Azerbaijan, Republic of Georgia, Moldavia). TRANSMISSION: Infection is carried both on and within the seed. Seed infestation in pods showing infection was 50-80%. Seed formation, size and germination and seedling growth are adversely affected (12: 264; 49, 3059). Conida are presumably dispersed by water-splash and viability is retained in host debris on the soil surface between crop seasons.

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.

The growth of barley grass (Hordeum leporinum) in annual pasture. 4. The effect of some management practices on barley grass content

1968 ◽  
Vol 8 (35) ◽  
pp. 706 ◽  
Author(s):  
DF Smith
Keyword(s):  
Management Practices ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Botanical Composition ◽  
Lolium Rigidum ◽  
Seed Setting ◽  
Grass Seed ◽  
Hordeum Leporinum ◽  
Wimmera Ryegrass

The effects of three grazing treatments and three mowing treatments on the dominance of barley grass (Hordeum leporinum) in an annual pasture were examined. Different spring grazing patterns did not markedly alter the amount of seed. Mowing favoured the legume component; topping less so than cutting lower as for hay or silage. However, none of these practices totally prevented barley grass from setting seed, and their effects were partly offset by late irrigation. Oversowing with subterranean clover (Trifolium subterraneum) did reduce barley grass seed setting but alone u-as not effective in changing botanical composition. Compared with Wimmera ryegrass (Lolium rigidum), barley grass showed greater persistence.

Influence of environmental factors on the germination of barley grass (Hordeum glaucum) and annual ryegrass (Lolium rigidum)

1987 ◽  
Vol 27 (4) ◽  
pp. 525 ◽  
Author(s):  
PM Kloot
Keyword(s):  
Physical State ◽  
Soil Surface ◽  
Soil Disturbance ◽  
Chemical Characteristics ◽  
Field Observations ◽  
Soil Cores ◽  
Annual Ryegrass ◽  
Alkaline Soils ◽  
Lolium Rigidum ◽  
Undisturbed Soil

The ability of Hordeum glaucum to germinate and initially grow faster than Lolium rigidum was found to be influenced by the soil's physical state and its chemical characteristics. Glasshouse studies showed that the replacement of Lolium by Hordeum in undisturbed situations was due to the advantage of the latter having awned florets which anchor and lever the seed on smooth, compacted surfaces. Soil disturbance produces a broken surface upon which Hordeum has no advantage over Lolium. Hordeum is also able to germinate under higher osmotic pressures than is Lolium. Higher osmotic pressures will arise on stock camps and on alkaline soils where the salts are of biological and pedological origin respectively. Glasshouse and field observations showed that the top 3 mm of the soil surface are drier and more saline than the soil profile generally as indicated from measurements on soil cores. In undisturbed soil this surface layer will favour the dominance of Hordeum over Lolium. In cultivated soil the layer will be diluted throughout the depth of cultivation.

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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