The manipulation of species composition of natural pastures by grazing management on the northern slopes of New South Wales.

1985 ◽  
Vol 7 (1) ◽  
pp. 6 ◽  
Author(s):  
GM Lodge ◽  
RDB Whalley
1974 ◽  
Vol 14 (67) ◽  
pp. 231 ◽  
Author(s):  
OR Southwood ◽  
F Mengersen ◽  
PJ Milham

The effect of three rates of nitrogen (22.4, 44.8 and 89.6 kgNha-1 as anhydrous ammonia) and three seeding rates (67.3, 100.9, and 134.5 kg ha-1) on forage and grain production of two oat cultivars and on herbage nitrate-nitrogen concentration, was assessed at three sites in the southern New South Wales wheat belt. When oats were sown after two or three consecutive wheat crops nitrogen at 22.4 kg ha-1 was optimal for both forage and grain production. Herbage growth was best at the highest seeding rate (134.5 kg ha-1) but grain production was not influenced by seeding rate. Herbage growth of the oat cultivars Cooba and Coolabah was similar, but grain yields were higher from the latter. Herbage nitrate nitrogen increased linearly with nitrogen fertilizer application, levels that could be toxic to animals occurring in June. Cautious grazing management may be required during this period.


2006 ◽  
Vol 46 (4) ◽  
pp. 495 ◽  
Author(s):  
R. E. Jones ◽  
P. M. Dowling ◽  
D. L. Michalk ◽  
W. McG. King

There have been significant declines in the perennial grass (PG) content in native and sown pastures across temperate Australia. Not only has this reduced agricultural productivity, it has contributed to more serious degradation, such as loss of soil and biodiversity, decreasing water quality, and dryland salinity caused by rising watertables. Results from the Sustainable Grazing Systems Key Program (SGS) research undertaken at Carcoar on the Central Tablelands of New South Wales were reported by Michalk et al. (2003). This research indicated that grazing management tactics can be used to manipulate pasture composition, thereby changing animal production and water-use patterns. The main grazing tactic investigated was termed a summer grazing rest, where resting was imposed in late spring if PG composition was <50%. Reported in this present paper is an economic framework for valuing the long-term benefits of grazing management tactics. The framework involves the development of a bioeconomic modelling system that links a dynamic programming model with biophysical models for water and environmental processes, soil fertility, pasture growth, livestock energy requirements and the change in pasture species composition. The study concludes that long-term economic returns are improved by strategies, e.g. a summer rest, that lead to an increase in PG composition over time. The study also determined that environmental factors, such as deep drainage, runoff and soil loss, are reduced as perenniality is increased.


2003 ◽  
Vol 43 (8) ◽  
pp. 977 ◽  
Author(s):  
J. F. Graham ◽  
B. R. Cullen ◽  
G. M. Lodge ◽  
M. H. Andrew ◽  
B. P. Christy ◽  
...  

The effects of various grazing management systems on sown, naturalised, and native pastures were studied at 6 different locations in the temperate high rainfall zone (HRZ, >600 mm rainfall/year) of southern Australia, as part of the Sustainable Grazing Systems (SGS) Program. The treatments examined had different pasture species and fertiliser management, with grazing method ranging from set stocking (continuous grazing) to rotation with rests based on pre- and post-grazing herbage mass or season and plant phenology. Sites were located at: Albany, Western Australia; Manilla, Barraba, Nundle, New South Wales; (grazed by wethers); and Carcoar, New South Wales; Maindample, Ruffy, north-east Victoria; Vasey, western Victoria; (grazed by ewes and lambs).Grazing method significantly (P<0.001) influenced stocking rate (expressed as dry sheep equivalents (DSE)/ha), but effects were not consistent across sites. At Vasey the stocking rate of the rotation treatments ranged from 5 to 23% higher than the set stocked treatments depending upon year. For all sites, significant factors (P<0.001) affecting stocking rate were soil Olsen P, soil pH, grazing management (resting), legume percent, and an index of growing season effectiveness. Although total annual rainfall had a significant effect (P<0.002) in an initial analysis, its influence became non-significant (P>0.05), when a growing season index (P<0.001) was used. Non-significant (P>0.05) factors included solar radiation, annual average temperature, fertiliser applied in the current year, and average annual perennial and broadleaf percent composition. The implications of these data for productivity and sustainability (as assessed by perenniality and water use) were encouraging. Generally, there were positive relationships between increased stocking rate and the probability of achieving a zero mm soil water surplus in winter, and between increased productivity and the proportion of perennial grass species where extremes of treatments were compared at each site. The results indicate that stocking rate can be increased without jeopardising sustainability, that grazing management can bring about more sustainable pastures, that there is scope to increase productivity particularly through increasing soil fertility, and growing season length can be used to predict potential carrying capacity. These are positive outcomes that graziers in the HRZ of southern Australia can use to enhance productivity (thus profitability) and sustainability.


1972 ◽  
Vol 23 (2) ◽  
pp. 73 ◽  
Author(s):  
MA Borowitzka

The species diversity of the larger intertidal algae was determined at three sites along the coastline of Sydney, New South Wales. The changes in species diversity and species composition were correlated with height from mean of low water (MLW), distance from the edge of the rock platform at MLW, and distance from a sewer outfall (i.e. the degree of pollution). The total number of algal species was reduced in the vicinity of the outfall. This reduction was most evident in the Phaeophyceae and the Rhodophyceae. The maximum value of algal species diversity was also reduced at higher levels above MLW, away from the edge of the platform and near the outfalls.


1973 ◽  
Vol 13 (62) ◽  
pp. 259 ◽  
Author(s):  
H Brownlee

During an experiment conducted for eighteen months at Condobolin, New South Wales, the production and persistence of dryland lucerne grazed by Merino wethers at 10 ha-1 yr-1 were measured under set stocking and three rotational grazing treatments differing in length of spelling period between grazings (grazed one week in four, six or eight weeks). The results showed that although dry matter availability and lucerne survival increased with decreased grazing frequency, only 35 per cent of the lucerne survived in the treatment with the slowest rotation.


1965 ◽  
Vol 5 (18) ◽  
pp. 252 ◽  
Author(s):  
JD McFarlane

The wool growth by Merino ewes grazed on sown annual pastures and by Merino weaners grazed on sown perennial pastures was measured at six-weekly intervals for three years. The ewes were from four groups with different grazing treatments and the weaners were from two grazing treatments. Wool was clipped from tattooed mid-side areas and the weight of clean, oven-dry wool in each sample was determined and staple length and fibre diameter measured. In all pears and in all groups of sheep there were seasonal fluctuations in weight, length, and fibre diameter of the wool. Growth was rapid during autumn and late spring but retarded during winter and summer. With few exceptions the summer and winter minima were not significantly different. The exceptions were mainly due to the summer minimum for a group being less than the winter minimum for the same group ; only in two cases was the summer minimum significantly greater than the winter minimum, and in both of these there was drought during the autumn and winter. The results, obtained at Canberra, A.C.T., are considered representative of the southern and central tablelands of New South Wales.


2004 ◽  
Vol 10 (3) ◽  
pp. 180 ◽  
Author(s):  
DR. Cilla Kinross

Many windbreaks are being planted on the Tablelands of New South Wales, Australia to provide shelter for stock and crops, but little is known of the effect of these linear plantations on the regional bird community. This paper compares the avian diversity, density and species composition in a range of habitats in agricultural landscapes, including farm windbreaks, and draws conclusions as to the benefits of windbreaks to bird conservation. The data were collected between 1993 and 1997 with 12 visits to each of 84 sites, placed a priori into seven habitat types on six grazing properties in the Tablelands of New South Wales, Australia and analysed using ANOVA and canonical variate analysis to identify bird-habitat relationships and patterns. Species diversity and density were found to be highest in remnant woodland and lowest in grassland, but differences between other habitats were less robust. Windbreaks >19 m wide were closer in diversity and species composition to remnant woodland than windbreaks =15 m wide. Of the 105 bird species observed, 17 were confined to remnant woodland and 67 native species were observed using planted sites. These species were not, as had been predicted, entirely composed of generalist-opportunistic species, but, particularly in the wider planted sites, included several woodland species identified as declining in this region. Although clearly not as important as remnant woodland, farm windbreaks, shelterbelts and woodlots of suitable size and composition appear to contribute significantly to avian diversity in agricultural areas and their planting should be encouraged and supported by the rural community and government.


1989 ◽  
Vol 37 (5) ◽  
pp. 375 ◽  
Author(s):  
JH Leigh ◽  
DH Wood ◽  
MD Holgate ◽  
A Slee ◽  
MG Stanger

The effects of rabbits and kangaroos, and rabbits alone, on the biomass and species composition of a native grassland dominated by Stipa nitida/nodosa, Danthonia caespitosa and Aristida contorta, and a grassland dominated by the exotic species Hordeum glaucum, Vulpia spp., Medicago laciniata and the native Erodium crinitum growing at Yathong Nature Reserve in central New South Wales was monitored between 1979 and 1985. Rabbits generally favoured the grassy component; kangaroos also favoured grasses but less so. Changes in non-grass species composition due to grazing was generally insignificant. Changes in species composition due to seasonal differences in rainfall was highly significant. No new species appeared on plots exclosed from grazing for 10 years, suggesting that the grazing by livestock, rabbits, and kangaroos in the past has determined the present species composition. The annual biomass consumption by rabbits averaged over 6 years was 100-200 kg ha-1, which is equivalent to reducing the carrying capacity by one sheep for every 2-4 ha rabbit-infested area. In the native grassland the spatial pattern of rabbit grazing, as indicated by faecal pellet distribution, biomass removal, and percentage of 'unpalatable' species in the pasture, shows greatest grazing pressure to be within 50 m of the warren, grazing intensity dropping off from there to 300 m the greatest distance studied. From the start of the study 'palatable' species, especially grasses, were at their lowest density within 50 m of the warren; this appeared to be a historical effect of grazing. No patterns were discernible in the pasture dominated by introduced species. Little change in species composition of these grasslands can be expected under a wide range of grazing pressure, except close to rabbit warrens.


1990 ◽  
Vol 41 (1) ◽  
pp. 13 ◽  
Author(s):  
CA Gray ◽  
VC McDonall ◽  
DD Reid

This study examined spatial and temporal variability in the composition, distribution and relative abundance of by-catch from prawn trawl sampling in the Hawkesbury River, New South Wales. It also determined whether there were differences in the fauna between sections of the river that are open and closed to prawn trawling. By-catch was sampled monthly between March 1986 and February 1988 in three areas along the river that differed in distance from the mouth of the estuary and in salinity. The total incidental catch comprised 75 species of fish, 13 species of crustaceans and 5 species of molluscs: 42 species were commercially and/or recreationally important. Classification and ordination analyses showed that the species composition of the by-catch differed between the area closest to the mouth of the estuary and that furthest upstream, and that this difference was relatively consistent throughout time. The number of species in the by-catch decreased with increasing distance upstream. Annual and seasonal changes in the number of species were similar in all areas along the river: more species were caught in 1987 than in 1986, and in autumn and winter each year. In contrast, the number of individuals caught differed among areas and these differences varied between years. Similarly, seasonal fluctuations in the numbers of individuals caught varied between years, but these variations were similar in all areas. In the area furthest upstream there were no apparent differences in the numbers of species and individuals caught by prawn trawl sampling in sections of the river open or closed to prawn trawling.


1985 ◽  
Vol 12 (3) ◽  
pp. 515 ◽  
Author(s):  
SV Briggs ◽  
MT Maher ◽  
CC Davey

The results of six annual surveys of waterfowl hunters in New South Wales by mail card are reported. The aims of the survey were to ascertain reported distribution of hunting effort, size and composition of hunters' bags, and state of hunter origin. Hunting effort and waterfowl harvests were highest in southern inland New South Wales. Seasonal bag sizes varied between 15.8 and 27.2 ducks per hunter. Pacific black duck, grey teal and maned duck made up 88.6% of hunters' bags. About half the hunters in New South Wales originated from Victoria. Bag size and species composition, effect of reducing bag size on total harvest, regional bias in hunting effort and harvest, and annual variation in licence sales are discussed.


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