Factors Associated With Density of Mitchell Grass Pastures in North-Western New South Wales.

1997 ◽  
Vol 19 (1) ◽  
pp. 40 ◽  
Author(s):  
AM Bowman ◽  
DJ Munnich ◽  
KY Chan ◽  
J Brockwell
Keyword(s):  
Plant Density ◽  
Rhizobium Meliloti ◽  
New South ◽  
New South Wales ◽  
Good Condition ◽  
Grazing Pressure ◽  
Annual Species ◽  
Basal Diameter ◽  
Poor Condition ◽  
South Wales

Thirty-eight paddocks on 23 properties in the Walgett Shire of north-westem New South Wales were surveyed in April and May 1993 to identify factors that affected Mitchell grass (Astrebla lappacea) plant density. Low densities of Mitchell grass were associated with the occurrence of at least one flood in the last 20 years. Soils from paddocks described by landholders as in poor condition, and where Mitchell grass density was low, were more alkaline and had significantly higher electrical conductivity than soils from paddocks described as in good condition, and where Mitchell grass density was high. Paddocks in poor condition had higher organic carbon and mineralisable nitrogen levels and higher soil populations of Rhizobium meliloti. These latter characteristics were attributed to these pastures having a high component of annual species, including Medicago species, which returned substantial amounts of carbon and nitrogen to the soil. Where Mitchell grass density was moderate, other palatable species were common and biodiversity was high. However, in paddocks with the lowest densities of Mitchell grass, both annual species and unpalatable perennials were common. Low basal diameter of Mitchell grass plants and low Mitchell grass density, were associated with higher grazing pressure. The data suggested that the Mitchell grass ecosystem in north-westem New South Wales is prone to deterioration on the more alkaline and saline soils and where inundation by flooding or waterlogging is common.

The effects of grazing and season on the stability of Chloris Spp. (Windmill grasses) in natural pasture at Trangie, New South Wales.

1978 ◽  
Vol 1 (2) ◽  
pp. 106 ◽  
Author(s):  
DL Michalk ◽  
PK Herbert
Keyword(s):  
New South ◽  
New South Wales ◽  
Grazing Pressure ◽  
Basal Diameter ◽  
South Wales ◽  
Natural Pasture ◽  
Mean Diameter ◽  
The Mean ◽  
The Stability ◽  
Stocking Rates

A study of the density and basal diameter of Chloris acicularis Lindl. (syn. Enteropogon acicularis (LindlJLazar. - curly windmill grass) and C. truncata R. Br. (windmill grass) was made at two stocking rates over a period of eight years. The propor- tion of ground covered by these Chloris species varied widely with season, and to a lesser extent with grazing pressure. The density of both species increased in good seasons, while the mean diameter decreased because of the number of new seedlings. Although C. truncata seedlings were more numerous in good seasons, they did not survive as well as did C. acicularis seedlings during prolonged dry periods.

Corrigendum - Frequency of annual species of Medicago on the major soil groups of the Mcquarie region of New South Wales

1960 ◽  
Vol 11 (5) ◽  
pp. 705
Author(s):  
WD Andrew ◽  
FW Hely
Keyword(s):  
New South ◽  
New South Wales ◽  
Salt Content ◽  
Acid Group ◽  
Soluble Salt ◽  
Annual Species ◽  
South Wales ◽  
Soil Groups ◽  
Soil Habitat ◽  
Poor Drainage

The frequency of eight annual species of Medicago was determined on 10 soil groups in a region climatically favourable for medics. They occurred on nine of these, the overall frequency being in the order M. minima (L.) Bart. > M. denticulata Willd. > M. laciniata (L.) Mill., M. praecox DC., M. tribuloides Desr., and M. orbicularis (L.) Bart. > M. arabica (L.) Huds. and M. confinis Koch. M. minima was more tolerant of variation of soil habitat than any other medic in the region. M. denticulata was most commonly found on the soils of high soluble salt content and showed the greatest tolerance of poor drainage conditions. M. laciniata occurred in greatest abundance on soils of the well-drained brown acid group. M. praecox was most commonly found on soils with a compact gravelly surface. M. tribuloides was recorded on five soil groups but was common only on the black earths. M. orbicularis was confined to the black earth and red loam soils. M. arabica was rarely found, being restricted to lower, fertile, well-drained parts of the landscape, and M. confinis occurred only occasionally and then in association with M. denticulata.

Rhizobium as a factor in the re-establishment of legume-based pastures on clay soils of the wheat belt of north-western New South Wales

1998 ◽  
Vol 38 (6) ◽  
pp. 555 ◽  
Author(s):  
A. M. Bowman ◽  
D. M. Hebb ◽  
D. J. Munnich ◽  
J. Brockwell
Keyword(s):  
Nitrogen Fixation ◽  
Rhizobium Meliloti ◽  
New South ◽  
New South Wales ◽  
Clay Soils ◽  
Natural Fertility ◽  
Fixed Nitrogen ◽  
South Wales ◽  
Annual Medics ◽  
North Western

Summary. Populations of Rhizobium meliloti in self-mulching clay soils (Vertisols) at 48 sites on 27 properties in north-western New South Wales were classified according to number and ability to fix nitrogen with several species of Medicago. Rhizobia were counted using serial dilution, nodulation frequency, plant infection tests. Abilities of the soil populations to fix nitrogen were determined in the laboratory with whole-soil inoculation of Medicago seedlings in test tubes with shoots exposed to the atmosphere and roots within the tubes under bacteriological control, and in the field using a technique based on the natural abundance of 15N in the soil. The majority of soils contained >1000 cells of R. meliloti per gram. The major component of those populations fixed nitrogen with lucerne (Medicago sativa) and some components of some soils also fixed nitrogen with M. polymorpha, M. scutellata, M. littoralis, M. tornata, M. laciniata and Trigonella suavissima. However, a number of soils were located which contained few if any rhizobia effective in nitrogen fixation with M. polymorpha. Overall, the effectiveness of nitrogen fixation of the naturally occurring populations of R. meliloti in association with M. polymorpha, M. scutellata, M. littoralis and M. tornata was only 46% of the effectiveness of standard strains. At one particular site, where 10 lines of annual Medicago spp. were growing experimentally, fixed nitrogen as a proportion of shoot nitrogen averaged only 28%. At that site, there were no effective rhizobia for M. scutellata and it was wholly dependent on the soil as the source of its nitrogen. The results are discussed in relation to the need for a substantial input of legume nitrogen for restoring the natural fertility of self-mulching clay soils in degraded wheat lands of north-western New South Wales. It is suggested that lucerne, or perhaps other perennial Medicago spp., might fill this role better than annual medics such as M. polymorpha and M. scutellata that are more dependent than lucerne on specific strains of R. meliloti to meet their requirements for symbiotic nitrogen fixation.

Current Land Use in the Poplar Box (Eucalyptus Populnea) Lands.

1980 ◽  
Vol 2 (1) ◽  
pp. 31 ◽  
Author(s):  
EJ Weston ◽  
DF Thompson ◽  
BJ Scott
Keyword(s):  
Land Use ◽  
Native Species ◽  
Crop Production ◽  
New South ◽  
New South Wales ◽  
High Water ◽  
Grazing Pressure ◽  
Small Areas ◽  
South Wales ◽  
Domestic Livestock

Poplar box (Eucalyptus populnee) woodlands mainly occuron duplex, clay and red earth soils between the 300 mm and 750 mm rainfall isohyets. The poplar box lands have been occupied for from 100 to 150 years and have been modified extensively through tree felling, ringbarking, clearing, cultivation, burning and grazing by domestic livestock. The current land use is described for six vegetation groups which together comprise the poplar box lands. The eastern areas of the poplar box lands are mainly used for intensive agriculture based on wheat. barley and grain sorghum, with small areas sown to c~ops of high water demand. Mixed farming involves dairying (in Queensland) and fat lambs (in New South Wales) and broad-acre cereal and fodder cropping. Sheep and cattle grazing replace intensive crop production as the rainfall decreases. In all areas used for cropping the stability and fertility of the soil are of paramount importance in maintainihg production. The use of woodlands in areas of lower rainfall can lead to deterioration of the resource and to the encroachment of woody native species into the grazing lands. Because cropping is unreliable the opportunity to use cultivation to control woody regrowth is reduced. In central areas much of the land can be sown to improved pastures, but in western areas diversification is limited by the low rainfall and land use is restricted to grazing, initially only by sheep but now by sheep and cattle. Particularly in western New South Wales the increase in unpalatable shrubs and the decrease in available forage has resulted in low stocking rates, and high grazing pressure, making reclamation and pasture improvement difficult. In consequence many enterprises are becoming uneconomic.

Frequency of annual species of Medicago on the major soil groups of the Mcquarie region of New South Wales

1960 ◽  
Vol 11 (5) ◽  
pp. 705
Author(s):  
WD Andrew ◽  
FW Hely
Keyword(s):  
New South ◽  
New South Wales ◽  
Salt Content ◽  
Acid Group ◽  
Soluble Salt ◽  
Annual Species ◽  
South Wales ◽  
Soil Groups ◽  
Soil Habitat ◽  
Poor Drainage

The frequency of eight annual species of Medicago was determined on 10 soil groups in a region climatically favourable for medics. They occurred on nine of these, the overall frequency being in the order M. minima (L.) Bart. > M. denticulata Willd. > M. laciniata (L.) Mill., M. praecox DC., M. tribuloides Desr., and M. orbicularis (L.) Bart. > M. arabica (L.) Huds. and M. confinis Koch. M. minima was more tolerant of variation of soil habitat than any other medic in the region. M. denticulata was most commonly found on the soils of high soluble salt content and showed the greatest tolerance of poor drainage conditions. M. laciniata occurred in greatest abundance on soils of the well-drained brown acid group. M. praecox was most commonly found on soils with a compact gravelly surface. M. tribuloides was recorded on five soil groups but was common only on the black earths. M. orbicularis was confined to the black earth and red loam soils. M. arabica was rarely found, being restricted to lower, fertile, well-drained parts of the landscape, and M. confinis occurred only occasionally and then in association with M. denticulata.

Factors affecting nitrogen fixation by dryland lucerne in central-western New South Wales

2002 ◽  
Vol 42 (4) ◽  
pp. 439 ◽  
Author(s):  
A. M. Bowman ◽  
M. B. Peoples ◽  
W. Smith ◽  
J. Brockwell
Keyword(s):  
Nitrogen Fixation ◽  
Biomass Production ◽  
Plant Density ◽  
New South ◽  
Practical Implication ◽  
New South Wales ◽  
Early Years ◽  
Stand Age ◽  
Shoot Biomass ◽  
South Wales

Eight stands of dryland lucerne (Medicago sativa L.) cv. Trifecta were grown on a red-brown earth at Trangie, New South Wales. The stands were of varying age and plant density. Their biomass production and capacity to fix atmospheric nitrogen were measured on 15 occasions over a 5-year period (1995-99). Biomass production (shoot dry matter) ranged from 0.22 to 4.87 t/ha.year and nitrogen fixed from 1.8 to 78.6 kg/ha.year. Whereas biomass production was highest in summer periods, most nitrogen fixation took place in winter and autumn. Irrespective of stand age, greatest productivity occurred in the early years of the experiment and declined thereafter. Plant density varied from 6 to 21 plants/m2 at the commencement of the study and decreased over time. We conclude that the productive life of dryland lucerne stands in this environment is probably limited by frequent periods of moisture stress and high soil temperatures in summer. Stands with a lucerne density of 8 plants/m2 or better produced twice as much shoot biomass and fixed nearly double the amount of shoot N as did stands with densities of 7 plants/m2 or less. There was no relationship between the age of lucerne stands per se and biomass production or nitrogen fixation. The practical implication of this work for farmers in the dryland cropping zone of central-western New South Wales who wish to maximise nitrogen fixation from the lucerne phase of their cropping rotations is to establish and maintain dryland lucerne at 8 plants/m2 or better.

Effects of plant density and sowing date on grain yield of faba beans (Vicia faba L.) in northern New South Wales

1986 ◽  
Vol 26 (4) ◽  
pp. 493 ◽  
Author(s):  
H Marcellos ◽  
GA Constable
Keyword(s):  
Grain Yield ◽  
Vicia Faba ◽  
Plant Density ◽  
New South ◽  
New South Wales ◽  
Sowing Date ◽  
South Wales ◽  
Vicia Faba L ◽  
Faba Beans ◽  
High Yields

The effects of varying plant density and sowing date on grain yield of faba beans (Vicia faba L.) were determined in 6 experiments at Tamworth and Narrabri in northern New South Wales. The graph of grain yield rose to an asymptote as plant density was increased. Under conditions favouring high yields, a plant density of 20 m-2 gave near maximum grain yields, but for a wider range of circumstances a plant density of 30-35 m-2 was appropriate. If sowing was delayed after the end of April, grain yield was reduced as was dry matter yield and the duration of pod-filling. Late sowing also lowered the height of the first pod above ground, and increased the likelihood of yield loss through foliar disease.

Frequencies of annual species of Medicago on subgroups of the grey and brown soils of heavy texture of the Macquarie Region of New South Wales

1962 ◽  
Vol 13 (5) ◽  
pp. 801 ◽  
Author(s):  
FW Hely
Keyword(s):  
New South ◽  
New South Wales ◽  
Low Frequency ◽  
The Other ◽  
Annual Species ◽  
South Wales

Four broad subgroups were recognized in the grey and brown soils of heavy texture in the Macquarie region of central New South Wales, and five annual species of Medicago (medics) were found occurring naturally on these soils, but with different frequencies on various subgroups. Some medic material was found in all quadrats on three subgroups and in nearly all fields and the majority of quadrats on the soils of the other. Medicago denticulata Willd. dominated one subgroup, occurring in all quadrats of all fields sampled. This species also occurred in approximately three quarters of the fields and half the quadrats sampled on two other subgroups, and was found in half the fields and a quarter of the quadrats of the fourth subgroup. Medicago minima (L.) Bart. showed a contrary preference, occurring with only slight frequency on the first, and with greatest frequency on the fourth subgroup. Medicago laciniata (L.) Mill. and Medicago tribuloides Desr. were of an intermediate nature and occurred principally on soils of the second and third subgroups. Medicago praecox DC. was found only on soils of the fourth subgroup and at low frequency. The nature of associations between medics showed that differences existed between subgroups of soils with respect to the preference of one species or another for them.

Changes in fallow weed species in continuous wheat in northern New South Wales 1981-1990

2000 ◽  
Vol 40 (6) ◽  
pp. 831 ◽  
Author(s):  
G. A. Wicks ◽  
W. L. Felton ◽  
R. D. Murison ◽  
R. J. Martin
Keyword(s):  
Plant Density ◽  
New South ◽  
Perennial Grass ◽  
New South Wales ◽  
Perennial Grasses ◽  
No Tillage ◽  
Weed Species ◽  
Wild Oats ◽  
Wild Mustard ◽  
South Wales

Four experiments in northern New South Wales comparing fallow management treatments of no-tillage, cultivated with the stubble retained, and cultivated with the stubble burned, from 1981 to 1990, were sampled for weeds between wheat harvest and seeding on a number of occasions during this period. Eighty weed species were identified, 23 of which were found at all 4 sites but only 13 were recorded in the samples taken. These were dwarf amaranth, wild turnip, spear thistle, Australian bindweed, fleabane, bladder ketmia, prickly lettuce, turnip weed, variegated thistle, common sowthistle, dandelion, wild oats and native millet. The density of weeds during the fallow period decreased by 97% from 1981 to 1990 with some species eliminated, probably because of the herbicides used, particularly glyphosate and chlorsulfuron. These included Boggabri and redroot amaranth, button grass, caustic weed, dense crassula, fat hen, legumes, common peppercress, hedge mustard, London rocket, shepherd’s purse, wild mustard, sorghum-almum, paradoxa grass, wild zinnia, and wireweed. Twenty-four weed species were classified as a problem or a potential problem in the future at 1 or more sites. Seventeen weed species, including perennial grasses, often were tolerant to glyphosate at the rates used. The densities of common sowthistle and wild oat were reduced after 10 years, but still remained at all 4 sites. Plant density of species with wind-blown seeds was greater in no-tillage plots than stubble-retained or stubble-burned plots. Weeds whose seeds are dispersed by wind and weeds tolerant to glyphosate were the most troublesome. The perennial grass native millet increased at all 4 sites.

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