Control of vegetative and reproductive growth in sand burr (Cenchrus longispinus)

1974 ◽  
Vol 14 (71) ◽  
pp. 764 ◽  
Author(s):  
JD Twentyman
Keyword(s):  
Sand Dunes ◽  
Natural Populations ◽  
Soil Surface ◽  
Cereal Crops ◽  
Medicago Littoralis ◽  
Survival And Growth ◽  
Second Year ◽  
Vegetative And Reproductive Growth ◽  
Western Victoria ◽  
North Western

Seeds and seedlings of the annual weed sand burr (Cenchrus longispinus) were introduced into undisturbed vegetation and fallowed soil in north-western Victoria. Survival and growth of the sand burr plants was significantly reduced on areas with a high density of skeleton weed (Chondrilla juncea), and on soils of heavy texture. The results suggest that sand burr will be confined to the margins of sand dunes and other places where the soil surface is sandy and relatively free of skeleton weed. Natural populations of sand burr produced sufficient dormant seeds in the stubble after cereal crops to enable the plant to persist through several years of ley pasture. Harbinger medic (Medicago littoralis) and lucerne (M. sativa) were sown under the cereal at two sites in 1971 to control sand burr seeding. Harbinger medic reduced sand burr density in the stubble at one site, but did not reduce seed production. Lucerne sown at 3.8 kg ha-1 or above reduced the number of dormant seeds formed in the stubble at the two sites. In the second year of pasture, the suppression of sand burr was independent of lucerne sowing rate.

Diet of the House Mouse, Mus domesticus, in the Mallee Wheatlands of North-Western Victoria

1991 ◽  
Vol 18 (1) ◽  
pp. 1 ◽  
Author(s):  
CR Tann ◽  
GR Singleton ◽  
BJ Coman
Keyword(s):  
Climatic Factors ◽  
Stomach Contents ◽  
Nutritional Factors ◽  
Annual Peak ◽  
Food Quantity ◽  
Cereal Grain ◽  
Seed Reserves ◽  
Second Year ◽  
Western Victoria ◽  
North Western

The quality and/or quantity of food available to mice at key times may be important in generating plagues. This study examined the diet and breeding performance of mice over two years in the mallee wheatlands of Victoria. Mice were trapped approximately every 6th week and their stomach contents examined for seven categories of food. Indices of occurrence and estimates of percentage volumes of each category indicated that cereal seeds were the staple food of mice. They bred earlier in the second year, but in both years there was a pulse of invertebrates and fresh grass seeds in the diet before the onset of breeding. These pulses occurred when seed reserves ['mature' (>3 months) cereal and dicotyledon seeds] were low. Mice, however, were highly responsive to changes in the availability of different food classes throughout the study. Thus the relative influences of nutritional factors (food quality) and availability of food (food quantity) on the onset of breeding were difficult to determine. The annual peak in female breeding coincided with the availability of fresh cereal grain. Breeding ceased in autumn each year despite the presence of ample 'mature' cereal seeds. Investigations of the effect of climatic factors on timing and abundance of nutrients in the environment is essential for an understanding of their influence on the population dynamics of mice.

scholarly journals SURVIVAL AND GROWTH OF WHITE SPRUCE WILDLINGS AND COASTAL NURSERY SEEDLINGS IN THE INTERIOR OF BRITISH COLUMBIA

1966 ◽  
Vol 42 (4) ◽  
pp. 346-349 ◽  
Author(s):  
S. Eis
Keyword(s):  
Mineral Soil ◽  
Soil Surface ◽  
White Spruce ◽  
First Year ◽  
Height Increment ◽  
Undisturbed Soil ◽  
Nursery Stock ◽  
Survival And Development ◽  
Survival And Growth ◽  
Second Year

Survival and development of outplanted 2-0 and 2-1 white spruce nursery stock, transplanted 3-0 and 4-0 wildlings and 3-0 and 4-0 undisturbed wildlings are compared. Mortality was negligible in all groups. Planting check caused a 47% reduction in height increment during the first year and 15% during the second year after planting. The height increment was best related to the height growth during the previous year and total height of the planting stock. Insignificant differences were found between plants on undisturbed soil surface and those on exposed mineral soil.

Leaf spot and dry rot of lettuce caused by Xanthomonas vitians (Brown) Dowson

1963 ◽  
Vol 14 (6) ◽  
pp. 778 ◽  
Author(s):  
DE Harrison
Keyword(s):  
Leaf Spot ◽  
Early Spring ◽  
Late Winter ◽  
Laboratory Studies ◽  
Dry Rot ◽  
Complete Destruction ◽  
Western Victoria ◽  
Valley Area ◽  
North Western

During the late winter and early spring of 1960, and again to a lesser extent in 1961 and 1962, many lettuce crops in the Murray Valley area of north-western Victoria were seriously affected by a disease characterized by blackening, dry rotting, and collapse of the affected leaves. The incidence of disease varied from about 10% up to practically complete destruction of some plantings. A yellow bacterium was consistently isolated from affected plants and proved to be pathogenic to lettuce. Laboratory studies have shown that the organism agrees closely with the recorded description of Xanthomonas vitians (Brown) Dowson, which has not, apparently, been previously studied in Australia.

scholarly journals Effects of substrate availability and competing vegetation on natural regeneration of white spruce on logged boreal mixedwood sites

2018 ◽  
Vol 48 (4) ◽  
pp. 324-332 ◽  
Author(s):  
Nicola A. Kokkonen ◽  
S. Ellen Macdonald ◽  
Ian Curran ◽  
Simon M. Landhäusser ◽  
Victor J. Lieffers
Keyword(s):  
Picea Glauca ◽  
Natural Regeneration ◽  
Negative Impact ◽  
Mineral Soil ◽  
Soil Surface ◽  
White Spruce ◽  
Solid Wood ◽  
Seedling Mortality ◽  
Competing Vegetation ◽  
Survival And Growth

Given a seed source, the quality of available substrates is a key factor in determining the success of white spruce (Picea glauca (Moench) Voss) natural regeneration. We examined the influence of substrate and competing vegetation on survival and growth of natural regeneration of white spruce up to 4 years following harvesting in deciduous-dominated upland boreal mixedwood sites. Feather moss, thick soil surface organic layers, litter, and solid wood were poor substrates for establishment. Early successional mosses establishing on mineral soil, thin organics, and rotten wood were generally favourable microsites but were not highly available on postharvest sites. Mineral soil substrates were not as suitable as expected, likely because on a postlogged site, they are associated with unfavourable environmental characteristics (e.g., low nutrient availability, exposure). There was some evidence that survival and growth of seedlings were improved by surrounding vegetation in the first years, but heavy competing vegetation had a negative impact on older seedlings. Burial by aspen litter greatly increased seedling mortality, especially when combined with a brief period of submergence due to heavy spring snowmelt. The results provide insight into conditions under which natural regeneration could be an option for establishing white spruce following harvesting of deciduous-dominated boreal mixedwood forests.

Aeolian Environments

2005 ◽  
Author(s):  
Eduard Koster
Keyword(s):  
Sand Dunes ◽  
Ural Mountain ◽  
Aeolian Processes ◽  
The North ◽  
Aeolian Deposits ◽  
The World ◽  
Western Border ◽  
Late Weichselian ◽  
The Baltic ◽  
North Western

The literature on aeolian processes and on aeolian morphological and sedimentological features has shown a dramatic increase during the last decade. A variety of textbooks, extensive reviews, and special issues of journal volumes devoted to aeolian research have been published (Nordstrom et al. 1990; Pye and Tsoar 1990; Kozarski 1991; Pye 1993; Pye and Lancaster 1993; Cooke et al. 1993; Lancaster 1995; Tchakerian 1995; Livingstone and Warren 1996; Goudie et al. 1999). However, not surprisingly the majority of these studies discuss aeolian processes and phenomena in the extensive warm arid regions of the world. The results of aeolian research in the less extensive, but still impressive, cold arid environments of the world are only available in a diversity of articles. At best they are only briefly mentioned in textbooks on aeolian geomorphology (Koster 1988, 1995; McKenna-Neuman 1993). Likewise, the literature with respect to wind-driven deposits in western Europe is scattered and not easily accessible. The aeolian geological record for Europe, as reflected in the ‘European sand belt’ in the north-western and central European Lowlands, which extends from Britain to the Polish–Russian border, is known in great detail (Koster 1988; van Geel et al. 1989; Böse 1991). Zeeberg (1998) showed that extensive aeolian deposits progress with two separate arms into the Baltic Region, and into Belorussia and northernmost Ukraine. Recently, Mangerud et al. (1999) concluded that the sand belt extends even to the Pechora lowlands close to the north-western border of the Ural mountain range in Russia. Sand dunes and cover sands are widespread and well developed in this easternmost extension of the European sand belt. The northerly edges of this sand belt more or less coincide with the maximal position of the Late Weichselian (Devensian, Vistulian) ice sheet, while the southern edges grade into coverloams or sandy loess and loess (Mücher 1986; Siebertz 1988; Antoine et al. 1999). However, along these southern edges the dune fields and sand sheets regionally are derived from different sources, such as the sands of the Keuper Formation or the floodplains of the Rhine and Main rivers.

Uptake by grass and transfer to soil of nitrogen from 15N-labelled legume materials applied to a Rhodes grass pasture

1983 ◽  
Vol 34 (4) ◽  
pp. 367 ◽  
Author(s):  
I Vallis
Keyword(s):  
Linear Relationship ◽  
Dry Matter ◽  
Soil Surface ◽  
First Year ◽  
Rhodes Grass ◽  
Leaf Material ◽  
South Eastern ◽  
Non Linear ◽  
Second Year

Unground legume materials labelled with 15N were applied to the soil surface under a Rhodes grass pasture in south-eastern Queensland and the recovery of the applied 15N was followed over periods of 1-3 years. Comparisons were made between two legumes, Macroptiliurn atropurpureurn cv. Siratro and Desrnodiurn intorturn cv. Greenleaf, between leaf and stem materials of different nitrogen (N) concentrations (0.5-3.8% N), and between fresh and dried materials. After 1 year, 15N in the applied materials had decreased by 25-91%, and 7-25% was recovered in the Rhodes grass. Except for leaf material of Greenleaf, these changes showed a positive, non-linear relationship to the percentage of N (%N) in the applied materials. The changes for leaves of Greenleaf were less than would be predicted from their %N. Drying Siratro leaves and stems before applying them to the soil surface did not significantly affect the above changes. For N-poor materials (0.5-1.8% N) applied at 380-1360 g dry matter m-2, uptake of 15N by Rhodes grass was greater in the second year than in the first year, whereas for N-rich materials (3.8%N) applied at 140 g dry matter m-2 uptake of 15N in the second and third years was only 23 and 12% respectively of that in the first year.

Regional divergence and inbreeding in Eucalyptus cladocalyx (Myrtaceae)

2003 ◽  
Vol 51 (4) ◽  
pp. 393 ◽  
Author(s):  
M. W. McDonald ◽  
M. Rawlings ◽  
P. A. Butcher ◽  
J. C. Bell
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
South Australia ◽  
Natural Distribution ◽  
Flinders Ranges ◽  
Outcrossing Rates ◽  
Low Levels ◽  
Western Victoria ◽  
Ornamental Species ◽  
Regional Divergence

Eucalyptus cladocalyx F.Muell. is a widely cultivated tree in dryland southern Australia. It is grown for firewood, timber production and as a windbreak and ornamental species. Natural populations of E. cladocalyx are endemic to South Australia where they occur in three disjunct regions. This study assessed the mating system and patterns of genetic diversity in natural populations of E. cladocalyx by using allozymes. Populations had relatively low levels of genetic diversity (HE = 0.148) and high levels of genetic divergence (θ = 0.26) among populations, similar to other regionally distributed eucalypts. Populations clustered into three distinct groups, which corresponded to its disjunct natural distribution. Genetic differentiation among populations and between regions was highly significant. Relatively high levels of inbreeding (tm = 0.57) were detected in natural populations of E.�cladocalyx. Outcrossing rates were highly variable among families, ranging from 0 to 100%. One-third of families from four populations had outcrossing rates that were not significantly different from zero. The origins of three commercially significant, cultivated stands of E. cladocalyx were also assessed. Allozyme profiles of cultivated stands from Wail and Lismore in western Victoria suggested origins in the Wirrabara region of the southern Flinders Ranges, while a cultivated stand of E. cladocalyx var. nana Hort. ex Yates had an allozyme profile consistent with origins in the Eyre Peninsula region. The results are discussed in relation to the species' morphological variation, biogeography and the implications for its domestication and conservation.

Control of Amsinckia spp. by the pastures of north-western Victoria

1965 ◽  
Vol 5 (19) ◽  
pp. 500
Author(s):  
DJ Connor
Keyword(s):  
Seed Production ◽  
Subterranean Clover ◽  
Barrel Medic ◽  
Limited Application ◽  
One Year ◽  
The One ◽  
Western Victoria ◽  
Establishment Phase ◽  
North Western ◽  
Very High

Amsinckia is a serious weed in the wheat growing areas of north-western Victoria. It is successful in the inter-crop pastures, based upon barrel medic, because it grows faster than barrel medic in the cooler months of May to August. In addition, the rapid growth in height associated with the change from rosette to elongating phases ensures a height advantage over the pasture species when the flush of pasture growth does commence. Seed production by each Amsinckia plant is very high, and for this reason any competitive restriction obtained in one year is not necessarily reflected in the establishment phase of the next. Subterranean clover c.v. Clare is more competitive than barrel medic and was able to eliminate Amsinckia from the sward in two years. However it has only limited application in the pastures of north-western Victoria. A mowing treatment was carried out at the commencement of Amsinckia flowering, for this coincides with the beginning of rapid pasture growth. Regrowth produced a reversal of height relationships within the pasture and enabled barrel medic to shade Amsinckia BJ this treatment growth and seed production of Amsinckia were reduced by 99 per cent within the one season.

Carbon resource sharing and rhizome expansion of Phalaris aquatica plants in grazed pastures

2005 ◽  
Vol 32 (1) ◽  
pp. 79 ◽  
Author(s):  
Brendan R. Cullen ◽  
David F. Chapman ◽  
Paul E. Quigley
Keyword(s):  
Resource Sharing ◽  
Seasonal Pattern ◽  
Soil Surface ◽  
Deep Roots ◽  
Phalaris Aquatica ◽  
Plant Parts ◽  
Grazed Pastures ◽  
Below Ground ◽  
Grazing Systems ◽  
Western Victoria

The patterns of carbon (C) resource sharing and new rhizome development in phalaris (Phalaris aquatica L. cv. Australian) were examined in grazed pastures in western Victoria. The seasonal pattern of new rhizome growth was similar under the four grazing systems tested. New rhizome production was infrequent but concentrated in winter. The phalaris plants maintained more than 1600 kg DW ha–1 of non-assimilating material beneath the soil surface (0–5 cm). Gaseous 14C was fed into plants in the field to determine if these below ground structures continued to be supported by the C assimilating tillers. The results indicated that the primary tiller does provide C to support the growth of secondary and tertiary tillers derived from its axillary buds. There was some evidence that C was exported from the fed tiller to non-assimilating plant structures. The old reproductive tiller bases (from which the assimilating tillers originate) received some C support, suggesting that this was maintained because it had deep roots attached. C export to older plant parts declined, which may lead to plant fragmentation.

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