Fertiliser and grazing effects on production and botanical composition ofnative grasslands in south-east Australia

2003 ◽  
Vol 43 (8) ◽  
pp. 843 ◽  
Author(s):  
D. L. Garden ◽  
N. J. S. Ellis ◽  
M. A. Rab ◽  
C. M. Langford ◽  
W. H. Johnston ◽  
...  
Keyword(s):  
Ground Cover ◽  
Trigger Points ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Soil P ◽  
Native Grasslands ◽  
Annual Grasses ◽  
Weedy Species ◽  
Grazing Systems ◽  
Sheep Production

The effects of application of superphosphate and grazing on production and botanical composition of native grasslands were investigated at 3 locations in the high rainfall zone of south-east Australia. These studies were conducted as part of the Sustainable Grazing Systems Key Program, which investigated various aspects of grassland productivity and sustainability between 1996 and 2001. Grasslands in this study either had high contents of Themeda australis or Austrodanthonia spp., or were based on a degraded Austrodanthonia spp. grassland with a high content of annual and weedy species. All sites used increasing levels of superphosphate application (nil, low, medium and high) as treatments, with clover being added in some treatments at 1 site, and herbicide in 1 treatment at another site. Grazing (sheep) was continuous at 1 site (with stocking rates matched to pasture productivity) and intermittent at other sites, with grazing being dictated by available herbage between defined trigger points. Climate was monitored and changes in soil P, herbage mass, botanical composition, ground cover and sheep production recorded. Changes in composition resulting from the treatments varied between sites. At the continuously grazed Austrodanthonia spp. site, there was a decline in native perennial grasses throughout the experiment and an increase in exotic annual grasses in spring where superphosphate was applied. The grassland at the T. australis site remained relatively stable, which may have been due to the limited amount of grazing applied. The degraded Austrodanthonia�spp. grassland showed wide seasonal fluctuations in annual species. There were no clear effects of treatments at the latter 2 sites. Sheep production increased with increased superphosphate application at the continuously grazed Austrodanthonia spp. site, but there was little effect at the other 2 sites. Recommendations are made for sustainable management of native grasslands depending on their current botanical state.

Productivity and intensive sheep stocking over a five-year period

1967 ◽  
Vol 69 (1) ◽  
pp. 47-69 ◽  
Author(s):  
C. R. W. Spedding ◽  
J. E. Betts ◽  
R. V. Large ◽  
I. A. N. Wilson ◽  
P. D. Penning
Keyword(s):  
Milk Yield ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Economic Implications ◽  
Production Processes ◽  
Percentage Weight ◽  
Grazing Systems ◽  
Sheep Production ◽  
Stocking Rates

During the last ten years or so, the management of sheep for intensive lamb production has been studied on a considerable scale, and a variety of grazing systems have been investigated (Dickson, 1959; Cooper, 1959; Spedding & Large, 1959; Boaz, 1959). It is still too soon to specify precisely the place that any of these systems should occupy in sheep-production processes, in relation to breed, lambing percentage, weight of lamb at slaughter, stocking rate, botanical composition of the pasture, size of ewe and level of her milk yield. Quite apart from these biological considerations, the full economic implications are by no means clear. What has emerged most clearly, however, is that much higher stocking rates can be tolerated than had generally been regarded as safe and that, at these stocking rates, productivity can be extremely high.

Response of Mediterranean grassland to phosphate and stocking rates: biomass production and botanical composition

1991 ◽  
Vol 116 (1) ◽  
pp. 37-46 ◽  
Author(s):  
A. E. Osman ◽  
P. S. Cocks ◽  
L. Russi ◽  
M. A. Pagnotta
Keyword(s):  
Seed Mass ◽  
Biomass Productivity ◽  
Ground Cover ◽  
Botanical Composition ◽  
Pasture Production ◽  
P Deficiency ◽  
Soil P ◽  
Legume Seeds ◽  
Native Grassland ◽  
Stocking Rates

SUMMARYThree rates of phosphate (0, 25, and 60 kg/ha P2O5) were applied to phosphorus-deficient native grassland at Tel Hadya, in northern Syria, and biomass productivity, botanical composition and number of legume seeds in the soil were monitored for five seasons (1984/85–1988/89). The experiment was grazed at low (0·8 sheep/ha per year) and high (1·7 sheep/ha per year) stocking rates from the second to the fourth seasons of the experiment; in the fifth season, the low and high stocking rates were increased to 1·1 and 2·3 sheep/ha per year, respectively. The experimental site was typical of native grassland within the cereal zone of west Asia, where cropping is not possible because of shallow, stony soils and steep slopes.The results showed that annual applications of phosphorus, even as low as 25 kg P2O5/ha, alleviated the deficiency in soil P and resulted in improved pasture production, even in dry years. Legume production showed the greatest response to P, increasing by 0·3–3 times the production of the control treatments. By the fifth season, legume seed mass had increased threefold and number of seeds sixfold in the P-treated plots, compared with the first season, while in the control plots there was little change. Rain-use efficiency on the P-treated plots was more than double that of the controls by the fourth and fifth seasons.Practical application of the results depends on whether (i) legumes are as frequent in native grasslands, as a whole, as they are at Tel Hadya, (ii) the P deficiency observed at Tel Hadya is widespread, and (iii) grazing of communally owned grasslands can be controlled. It is suggested that all three criteria will often be fulfilled and, therefore, that grassland productivity in west Asia could be substantially increased. Furthermore, the results suggest that above-ground cover and soil organic matter will also increase after P application, both of which will help to reduce soil erosion and thereby increase the sustainability of livestock production in west Asia.

scholarly journals Changes in yellow bristle grass (Setaria pumila) abundance after drought implications for pasture management

2009 ◽  
Vol 62 ◽  
pp. 211-216 ◽  
Author(s):  
K.N. Tozer ◽  
T.K. James ◽  
C.A. Cameron
Keyword(s):  
Key Management ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Annual Grass ◽  
Bare Ground ◽  
Pasture Management ◽  
Soil Calcium ◽  
Annual Grasses ◽  
Previous Summer

Yellow bristle grass (YBG) which is a summeractive annual grass reduces pasture quality and becomes unpalatable to stock as panicles mature Farmers are concerned that an extreme drought from November 2007 to March 2008 may have facilitated the spread of YBG and other summeractive annual grass weeds Botanical composition was assessed on 12 Waikato dairy farms in February 2009 and YBG abundance was related to key management factors These findings were compared with data collected from the same farms (February 2008) during the drought Between years ryegrass cover and the proportion of bare ground decreased These components were replaced by two summeractive annual grasses YBG and summer grass and to a lesser extent summeractive perennial grasses clovers and dicots In 2009 YBG cover was negatively associated with summeractive perennial grass cover and pH and positively associated with YBG cover in the previous summer and soil calcium levels

Impact of phosphorus application and sheep grazing on the botanical composition of sown pasture and naturalised, native grass pasture

2004 ◽  
Vol 55 (12) ◽  
pp. 1213 ◽  
Author(s):  
J. O. Hill ◽  
R. J. Simpson ◽  
A. D. Moore ◽  
P. Graham ◽  
D. F. Chapman
Keyword(s):  
Trifolium Subterraneum ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Annual Species ◽  
Basal Cover ◽  
Grazing Systems ◽  
P Application ◽  
Phosphorus Application ◽  
Stocking Rates

Botanical composition (basal cover) was measured in 4 replicated pasture treatments based on Phalaris aquatica and Trifolium subterraneum at Hall, ACT (unfertilised with low and high stocking rate; fertilised with low and high stocking rate) and in 2 unreplicated pasture treatments based on native perennial grasses (Austrodanthonia spp. and Microlaena stipoides) and T. subterraneum at Bookham, NSW (unfertilised and low stocking rate; fertilised and high stocking rate). Current economic pressures are encouraging graziers to increase their use of phosphorus (P) fertiliser and to adopt higher stocking rates. The objective of the research was to determine the changes in botanical composition that may result from these changes in grazing systems management. At Hall, annual species differed in their responses to P fertility. Notably, basal cover of Bromus spp. increased significantly with P application, whereas Vulpia spp. decreased significantly. Basal cover of T. subterraneum also increased significantly with P application when stocking rate was high, but was reduced by P application if stocking rate was low. Basal cover of perennial grasses (P. aquatica and Holcus lanatus) was significantly higher at low stocking rate when P was applied. The botanical composition of high stocking rate treatments was relatively stable over time, which contrasted with less stable composition at low stocking rate. At Bookham, fertilised pasture in unreplicated paddocks appeared to have a higher basal cover of productive annual species (i.e. Bromus spp. and T. subterraneum), but native perennial grasses appeared to have lower basal cover in comparison with the unfertilised area. These results indicated that in some cases, the influence of P fertiliser and high stocking rates on botanical composition was favourable (i.e. increased basal cover of P. aquatica and T. subterraneum) and in others it could be detrimental (i.e. lower basal cover of native perennial grasses).

Changes in the Quantitative Floristics in Some Astrebla Spp. (Mitchell Grass) Communities in South-Western Queensland in Relation to Trends in Seasonal Rainfall

1981 ◽  
Vol 29 (5) ◽  
pp. 533 ◽  
Author(s):  
DM Orr
Keyword(s):  
Relative Abundance ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Seasonal Rainfall ◽  
Individual Species ◽  
Botanical Composition ◽  
Basal Cover ◽  
Wide Range ◽  
Annual Grasses

Seasonal changes in the quantitative floristics at a wide range of Astrebla grassland sites in south-western Queensland were monitored between 1972 and 1980 with a wheel point apparatus. Changes in the floristics were measured in terms of both relative abundance and basal cover. A large increase in the relative abundance of perennial grasses, particularly Aristida latifolia, Astrebla spp. and Dichanthium sericeum, occurred between 1972 and 1976. This increase was at the expense of annual grasses and forbs which declined in both relative abundance and number of genera present. The relative abundance of perennial grasses declined between 1978 and 1980 and this was associated with a large increase in the forbs such as Daucus glochidiatus and Plantago spp., particularly at southern sites. The contribution of annual grasses to botanical composition remained low throughout the period. Total basal cover differed between years although these differences were not significant. As perennial grass, particularly Astrebla spp., was the major vegetation component of total basal cover, changes in the latter were associated mainly with changes in the basal cover of Astrebla spp. Changes in the contribution of individual species to total basal cover were related to changes in the relative abundance of those species. Changes in botanical composition in Astrebla grassland may be influenced more by trends in seasonal rainfall than by grazing pressure.

Replacing a nitrophilous weed association with Phalaris aquatica and Medicago sativa on non-arable land

1979 ◽  
Vol 19 (99) ◽  
pp. 448 ◽  
Author(s):  
MH Campbell ◽  
WJ McDonald
Keyword(s):  
Medicago Sativa ◽  
Arable Land ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Control Treatment ◽  
Phalaris Aquatica ◽  
Late Autumn ◽  
South Wales ◽  
Herbicide Treatments ◽  
Annual Grasses

In an experiment (1974 to 1978) carried out on the Central Tablelands of New South Wales, the effects of nine herbicide treatments, two intervals between spraying and sowing, and sowing in late autumn, on the ability of Medicago sativa, Phalaris aquatica and Vicia dasycarpa to establish, develop and replace a nitrophilous weed association (broadleafed plants, annual grasses and native perennial grasses) were measured. Herbicide treatment of the resident species was necessary for the establishment and development of M. sativa and P. aquatica but not for the establishment of V. dasycarpa. Successful treatments were: 2,2-DPA + amitrole, 2,2-DPA + 2,4-D, paraquat + diquat and glyphosate. Intervals of 7 and 28 days between spraying and sowing had no differential effect on establishment. Sowing in late autumn resulted in successful establishment of all species. Over four years the percentage ground cover of sown species on the herbicide treatments increased from 0% in early 1974 to 49% in late 1978; the control treatment rose from 0% to 12%. The percentage ground cover of the nitrophilous weed association on the herbicide treatments decreased from 76% in 1974 to 27% in 1978; the control fell from 76% to 68%. The experiment demonstrated that a nitrophilous weed association can be replaced with perennial pasture species on non-arable land on the Central Tablelands by using aerial techniques. Further research is needed to determine the optimum time of spraying and sowing.

Establishment and development of surface sown pasture species in a nitrophilous weed association: effect of herbicide rate

1981 ◽  
Vol 21 (112) ◽  
pp. 531 ◽  
Author(s):  
MH Campbell ◽  
AR Gilmour ◽  
DT Vere
Keyword(s):  
Festuca Arundinacea ◽  
New South ◽  
Basal Area ◽  
Ground Cover ◽  
Weed Suppression ◽  
Perennial Grasses ◽  
Herbicide Treatment ◽  
South Wales ◽  
Annual Grasses ◽  
Association Effect

In an experiment carried out between 1976 and 1979 near Orange, New South Wales, the effects of four rates of glyphosate (0.1 25, 0.25, 0.5 and 1.0 kg/ha active ingredient (a.i.)) and three rates of amitrole (0.5, 0.75, 1.0 kg/ha a.i. in association with 2.5 kg/ha a.i. 2,2-DPA) on the suppression of a nitrophilous weed association (broadleafed plants, annual grasses, native perennial grasses, annual legumes) and the resultant establishment and development of surface sown pastures species (Medicago sativa, Phalaris aquatica, Dactylis glomerata, Festuca arundinacea) were measured. The length of weed suppression in the year of spraying (1976) was the most important factor in the eventual development of the sown species. Glyphosate at 1.0 kg/ha a.i. gave better weed suppression for longer (up to and beyond 23 weeks after spraying) than any other herbicide treatment and allowed sown species to establish and survive the first summer better and thus produce a better pasture three years later. Weed suppression between 8 and 19 weeks after spraying affected the initial establishment of sown species; in general, establishment was better on herbicide treatments that reduced ground cover of the weed association to less than 30% in this period. Rate of weed suppression had no effect because no sown species germinated in the eight weeks after spraying. Three years after treatment the ground cover of the nitrophilous weed association was 31% on the best herbicide treatment (glyphosate, 1.0 kg/ha a.i.) and 83% on the unsprayed control; the respective ground cover of sown species was 60% and 7%. The increase in ground cover of sown species during the three years was on most treatments almost entirely due to the increase in basal area of P. aquatica.

Temporary cropping in semi-arid shrublands increases native perennial grasses

2011 ◽  
Vol 33 (1) ◽  
pp. 67 ◽  
Author(s):  
Y. Alemseged ◽  
R. B. Hacker ◽  
W. J. Smith ◽  
G. J. Melville
Keyword(s):  
Perennial Grass ◽  
Stable State ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Grazing Management ◽  
Alternative Stable State ◽  
Pasture Production ◽  
Native Grasslands ◽  
Native Shrubs ◽  
Semi Arid

Thickening of native shrubs is a major problem in many ‘semi-arid woodlands’ as significant increase in shrub density is often negatively correlated with herbaceous vegetation and leads to reduced pasture production and soil erosion. This project aimed to test the hypothesis that temporary cropping (up to three crops in 15 years) consistently increases the density of native perennial grasses following the removal of shrubs. A total of 30 paddocks that had been cropped during the last 20 years were randomly selected using a satellite-based database that documented annual clearing and cropping history from 1987 to 2003. Paddocks were classified into four types based on clearing and cropping history and grazing management – not cleared (shrubs), regrowth (re-invaded by shrubs), set stocked (cropped and grazed), light/rotationally grazed (cropped and grazed). The responses of vegetation and soil (chemical and physical) properties to clearing and cropping were evaluated. Results indicated that ground cover, native perennial grass cover and standing dry matter were highest under light/rotationally grazed conditions. The shrub state represents a stable state within the Cobar pediplain brought about due to land-use change in the form of overgrazing and/or the removal of fire from the system. An alternative stable state was achieved as a result of disturbance in the form of clearing, cropping and grazing management thereby directly altering the shrub population. The resilience of this state is largely dependent on the grazing management system used and on the prevention of shrub from re-establishing while failure to control shrubs could lead to the re-emergence of the Shrub State. We conclude that native grasslands do regenerate following cropping after removal of shrubs. The importance of grazing management for restoring perennial ground cover following removal of shrubs and temporary cropping has been clearly demonstrated by the study.

Population dynamics and stability of Stylosanthes hamata cv. Verano in grazed pastures

1982 ◽  
Vol 33 (1) ◽  
pp. 63 ◽  
Author(s):  
CJ Gardener
Keyword(s):  
Perennial Grass ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Grazed Pastures ◽  
Stylosanthes Hamata ◽  
Wide Range ◽  
Annual Grasses ◽  
Seed Reserves ◽  
Stable Association

The longevity, regeneration and seed reserves of Stylosantes hamata cv. Verano were studied in grazed pastures at Lansdown, north Queensland, over a 9-year period. Stability was assessed in terms of frequency of appearance and fluctuations in botanical composition. Plants proved short-lived, with a half-life of only 3 months. The majority therefore died in their seedling year, and only 0.03 % survived to the end of the third year. In most years, S. hamata had to re-establish almost entirely from seed. Despite this, S. hamata was a highly persistent legume in the long term owing to its consistently high seed reserves and ready regeneration from seed. In one paddock, for example, it re-established in all quadrats after disappearing from 76% of them the previous year. This long-term persistence was not, however, reflected in yield stability; the content of S. hamata in one paddock changed from 6 to 68% in consecutive years. Low legume yields were recorded when seedlings of S, hamata competed poorly with the annual grasses. Higher yields occurred when more than 20 % of the population comprised perennial S. hamata plants. Retention of the perennial grasses reduced the amplitude of the fluctuations in yields of S. hamata. The perennial grass and S. hamata formed an intimate and stable association. There were only small effects of stocking rate and superphosphate on the persistence of S. hamata, which suggests that the legume is highly tolerant of a wide range of management levels, although more precise management is needed for high animal production.

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