Gaseous nitrogen loss from temperate perennial grass and clover dairy pastures in south-eastern Australia

2003 ◽  
Vol 54 (6) ◽  
pp. 561 ◽  
Author(s):  
R. J. Eckard ◽  
D. Chen ◽  
R. E. White ◽  
D. F. Chapman
Keyword(s):  
Ammonium Nitrate ◽  
Nitrogen Loss ◽  
Perennial Grass ◽  
Management Strategies ◽  
The Other ◽  
N Losses ◽  
South Eastern ◽  
Eastern Australia ◽  
Different Seasons ◽  
South Eastern Australia

The use of nitrogen (N) fertiliser on dairy pastures in south-eastern Australia has increased exponentially over the past 15 years. Concerns have been raised about the economic and environmental impact of N loss through volatilisation and denitrification. Emissions of NH3, N2, and N2O were measured for 3 years in the 4 different seasons from a grazed grass/clover pasture, with or without 200 kg N fertiliser/ha, applied as ammonium nitrate and urea.Nitrogen-fertilised treatments lost significantly more N than the control treatments in all cases. More NH3 was lost from urea-fertilised treatments than from either the control or ammonium nitrate treatments, whereas ammonium nitrate treatments lost significantly more N through denitrification than the control or urea treatments in all seasons, except for summer. More NH3 was lost in summer than in the other seasons, whereas denitrification and N2O losses were highest in winter and lowest in summer. The total annual NH3 loss from the control, ammonium nitrate, and urea treatments averaged 17, 32, and 57 kg N/ha.year, respectively. Annual denitrification losses were estimated at around 6, 15, and 13 kg N/ha.year for the control, ammonium nitrate, and urea treatments, respectively. Total gaseous N losses were estimated to be 23, 47, and 70 kg N/ha.year from the control, ammonium nitrate, and urea treatments respectively.Although the use of ammonium nitrate fertiliser would significantly reduce NH3 volatilisation losses in summer, this fertiliser costs 45% more per unit N than urea, so there is no economic justification for recommending its use over urea for the other seasons. However, the use of urea during the cooler, wetter months may result in significantly less denitrification loss. The results are discussed in terms of potential management strategies to improve fertiliser efficiency and reduce adverse effects on the environment.

Nitrogen balances in temperate perennial grass and clover dairy pastures in south-eastern Australia

2007 ◽  
Vol 58 (12) ◽  
pp. 1167 ◽  
Author(s):  
R. J. Eckard ◽  
D. F. Chapman ◽  
R. E. White
Keyword(s):  
Ammonium Nitrate ◽  
Management Practices ◽  
Perennial Grass ◽  
Dairy Farms ◽  
Nutrient Inputs ◽  
N Losses ◽  
Total N ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

Nitrogen (N) fertiliser use on dairy pastures in south-eastern Australia has increased exponentially over the past 15 years. Concurrently, imports of supplementary feed onto dairy farms have increased, adding further nutrients to the system. These trends raise questions about the environmental effects of higher nutrient inputs to dairy farms. To gauge possible effects, annual N balances were calculated from an experiment where N inputs and losses were measured for 3 years from non-irrigated grass/clover pastures receiving either no N fertiliser (Control) or 200 kg N/ha applied annually as ammonium nitrate or urea. Estimated total N inputs, averaged over the 3 years, were 154, 314, and 321 kg N/ha.year for the control, ammonium nitrate, and urea treatments, respectively, while N outputs in meat and milk were 75, 99, and 103 kg N/ha.year, respectively. The corresponding calculated N surplus was 79, 215, and 218 kg N/ha.year for the 3 treatments, respectively, and the ratio of product N/total-N inputs for the 3 treatments ranged from 50% in the control to 32% for both N treatments. Total N losses averaged 56, 102, and 119 kg N/ha.year, leaving a positive N balance of 23, 112, and 99 kg N/ha.year for the control, ammonium nitrate, and urea treatments, respectively. The ratio of product N/total-N inputs or the N surplus may be useful in monitoring the efficiency of conversion of N into animal products and the potential environmental effect at a whole-farm scale. However, additional decision support or modelling tools are required to provide information on specific N losses for a given set of conditions and management inputs. Given the large range in N losses there is opportunity for improving N-use efficiency in dairy pastures through a range of management practices and more tactical use of grain and N fertiliser.

Climatic conditions for seedling recruitment within perennial grass swards in south-eastern Australia

2012 ◽  
Vol 63 (4) ◽  
pp. 389 ◽  
Author(s):  
R. Thapa ◽  
D. R. Kemp ◽  
M. L. Mitchell
Keyword(s):  
Soil Moisture ◽  
New South ◽  
Perennial Grass ◽  
New South Wales ◽  
Climatic Conditions ◽  
South Eastern ◽  
South Wales ◽  
Eastern Australia ◽  
Moisture Conditions ◽  
South Eastern Australia

Recruitment of new perennial grass plants within existing grassland ecosystems is determined by seed availability, suitable microsites, nutrients and climatic conditions, water and temperatures. This paper reports on the development of criteria to predict recruitment events using modelled soil moisture conditions associated with recruitment of species in five field experiments at Orange (Phalaris aquatica), Trunkey Creek (Austrodanthonia spp.), and Wellington (Bothriochloa macra) in central New South Wales, Australia, and the frequency of those conditions during the past 30 years. Recruitment events were recorded when a rainfall event (median 68 mm across the three sites) kept the surface volumetric soil moisture (0–50 mm) above the permanent wilting point for at least 15 continuous days, allowing for, at most, two ‘dry days’ in between. A key finding from our study is that rainfall events creating favourable soil moisture conditions for seedling emergence typically occurred in the second half of February, sometimes extending to early March. Previously it was thought that recruitment would more likely occur through autumn, winter, and spring when rainfall in southern Australia is more reliable. The 30 years’ data (1975–2004) showed that the P. aquatica site had a median of 20 continuous moist days each year in February–March, whereas, there were 16 and 10 days for the Austrodanthonia and B. macra sites, respectively. The probabilities of exceeding seven or 15 continuous days of moist surface soil were 98% and 78% at the P. aquatica site, 91% and 49% at the Austrodanthonia site, and 73% and 30% at the B. macra site, and indicated that some recruitment is possible in most years. These analyses were extended to several sites across New South Wales, Victoria, and Tasmania to estimate the frequency with which recruitment could occur within natural swards. Across these sites, the probabilities of exceeding seven continuous days of soil moisture were >55% and of exceeding 15 continuous days were lower, which showed that suitable climatic conditions exist during late summer–early autumn across south-eastern Australia for a recruitment event to occur. Future research may show that the criteria developed in this paper could have wider regional application.

Attempts to measure the influence of dung beetles (Coleoptera: Scarabaeidae) on the field mortality of the bush fly Musca vetustissima Walker (Diptera: Muscidae) in south-eastern Australia

1983 ◽  
Vol 73 (1) ◽  
pp. 33-44 ◽  
Author(s):  
M. M. H. Wallace ◽  
M Tyndale-Biscoe
Keyword(s):  
Total Mortality ◽  
Single Species ◽  
Dung Beetle ◽  
Predatory Mites ◽  
Dung Beetles ◽  
The Other ◽  
South Eastern ◽  
Eastern Australia ◽  
Multiple Species ◽  
South Eastern Australia

AbstractThe immature stages of Musca vetustissima Wlk. in dung pads in south-eastern Australia suffered a high mortality through the actions of a complex array of dung organisms, including dung beetles (scarabaeids), predatory beetles (hydrophilids and histerids) and predatory mites (Macrocheles glaber (Müll.)). At times of high dung beetle numbers, it was possible to demonstrate a relationship between fly mortality and dung beetle numbers. Single-species dung beetle populations appeared to be as effective as multiple-species populations in reducing fly numbers, except that some benefit was derived from a combination of day- and night-flying species. When dung beetle numbers were low, their influence could not be measured because of the high mortalities already caused by the other dung fauna. It is suggested that in those circumstances any mortality caused by the dung beetles may simply have become substituted for an existing mortality caused by other fauna without adding to the total mortality.

Drought resistance of native and introduced perennial grasses of south-eastern Australia

2005 ◽  
Vol 56 (11) ◽  
pp. 1261 ◽  
Author(s):  
T. P. Bolger ◽  
A. R. Rivelli ◽  
D. L. Garden
Keyword(s):  
Drought Resistance ◽  
Perennial Grass ◽  
Livestock Grazing ◽  
Perennial Grasses ◽  
Severe Drought ◽  
South Eastern ◽  
Eastern Australia ◽  
Dehydration Avoidance ◽  
Leaf Survival ◽  
South Eastern Australia

Perennial grasses are the key to the economic and environmental sustainability of pastures for livestock grazing in south-eastern Australia. Mortality of perennial grasses can occur during drought periods and there is anecdotal evidence of differences in drought resistance among species, but information on the basic ecophysiological responses of these species to drought is lacking. An experiment was conducted to determine the responses of 7 native and 3 introduced perennial grass species to continuous drought. Leaf survival during severe drought varied among the species nearly 4-fold, from 11 to 40 days, and was considered a measure of their overall drought resistance. All of the species had good dehydration tolerance, so the differences in drought resistance were related more to their dehydration avoidance traits, specifically to the amount of water available to the plant at the point where plant transpiration became minimal. The native species had both the longest and shortest leaf survival periods, with the introduced species ranking intermediate. Species exhibited various morphological traits that contributed to dehydration avoidance during severe drought, including leaf folding or rolling, rapid leaf shedding, and large amounts of cuticular wax. The results are discussed in terms of their implications for perennial grass persistence in south-eastern and in south-western Australia.

Economic impact of Vulpia in temperate pasture systems in south-eastern Australia

2002 ◽  
Vol 42 (4) ◽  
pp. 465 ◽  
Author(s):  
D. T. Vere ◽  
P. M. Dowling ◽  
R. E. Jones ◽  
D. R. Kemp
Keyword(s):  
Management Strategies ◽  
Significant Proportion ◽  
Economic Benefits ◽  
Economic Effects ◽  
Economic Modelling ◽  
Benefit Cost Analysis ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

An increasing incidence of annual grasses is considered to be a primary cause of decline in the productivity of Australia's temperate pasture systems. In particular, Vulpia (silver grass) comprises a significant proportion of the biomass of many temperate pastures and can seriously affect livestock productivity. The main economic effects of Vulpia include reducing pasture carrying capacities, contaminating produce and competing with more desirable pasture species. This paper presents the results of an economic evaluation of the costs of Vulpia and the long-term benefits of improving Vulpia management in the high-rainfall areas of south-eastern Australia. The evaluation used an integrated economic modelling system that determined the grazing system and livestock industry impacts of Vulpia and translated these into measures of economic welfare change that enabled the benefit-cost analysis of various levels of Vulpia management to be undertaken. With a focus on wool, the analysis established the high annual costs of Vulpia to wool producers and consumers, together with substantial long-term economic benefits that could potentially result from reducing the incidence of Vulpia in pastures. Total annual costs to the wool industry in the temperate pasture zone of New South Wales and Victoria ranged between A$7 and $30 million, while the potential discounted net benefits to the Australian and international wool industries were between $32 and $287�million over a 15-year period at a real discount rate of 5%. These estimates provide a strong economic basis for promoting improved management strategies for reducing Vulpia incidence in pastures.

Influence of earthworms, Aporrectodea spp. (Lumbricidae), on lime burial in pasture soils in south-eastern Australia

Soil Research ◽  
1999 ◽  
Vol 37 (5) ◽  
pp. 831 ◽  
Author(s):  
G. H. Baker ◽  
P. J. Carter ◽  
V. J. Barrett
Keyword(s):  
Soil Ph ◽  
Mediterranean Climate ◽  
Soil Acidity ◽  
Agricultural Soils ◽  
The Other ◽  
Aporrectodea Caliginosa ◽  
Soil Layers ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

The relative abilities of 3 exotic lumbricid earthworms, the endogeic Aporrectodea caliginosa and A. trapezoides and the anecic A. longa, to bury surface-applied lime and help ameliorate soil acidity were measured in cages in 7 pasture soils in south-eastern Australia. All 3 species buried lime, mostly within the top 5 cm of the soil profile, but A. longa buried it deeper than A. caliginosa and A. trapezoides. A. longa significantly increased soil pH at 15–20 cm depth at some sites within 5 months (winter–spring, the earthworm ‘season’ in the Mediterranean climate of south-eastern Australia). Lime burial varied markedly between sites. These site differences were explained, at least in part, by variations in rainfall. Lime burial increased with earthworm density. A minimum density of 214 A. longa/m 2 was needed to significantly enhance lime burial within one season. Higher densities were required for the other two species. However, per unit of biomass, A. caliginosa and A. trapezoides were generally more able to bury lime in the upper soil layers (2 . 5–10 cm depth) than A. longa. Agricultural soils in south-eastern Australia are dominated by shallow burrowing species such as A. caliginosa and A. trapezoides. Deeper burrowers such as A. longa are rare. Introduction of A. longa to soils in high-rainfall regions of south-eastern Australia, where it does not presently occur, should enhance lime burial and help reduce soil acidity.

Climate variability effects on simulated pasture and animal production in the perennial pasture zone of south-eastern Australia.1. Between year variability in pasture and animal production

2003 ◽  
Vol 43 (10) ◽  
pp. 1211 ◽  
Author(s):  
S. G. Clark ◽  
E. A. Austen ◽  
T. Prance ◽  
P. D. Ball
Keyword(s):  
Climate Variability ◽  
Perennial Grass ◽  
Subterranean Clover ◽  
Animal Production ◽  
Annual Rainfall ◽  
Support Tool ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

Climate variability is a major constraint to farming in south-eastern Australia and one that is out of the farmers' control. However, a better understanding of long-term climate variability would be beneficial for on-farm management decisions. A series of long-term simulations were undertaken with the GrassGro decision support tool to determine the effect of climate variability on pasture and animal production at 6 locations in south-eastern Australia. The simulations ran from 89 to 119 years using daily weather records from each location. All simulations were for spring-lambing flocks of medium sized Merino ewes stocked at above-average district stocking rates, grazing well-fertilised, perennial grass–subterranean clover pastures. Annual rainfall total and, in particular, the distribution of rainfall during the year, were found to be more important than other weather variables in determining the amount of pasture grown in a year. The timing of the season opening rains (autumn break) was most important. The localities varied in their responses to climate variability, particularly in the timing of the autumn break; the pasture growth response to winter rainfall; and the relationship between rainfall and animal production.

Three new species of Fergusonina Malloch gall-flies (Diptera: Fergusoninidae) from terminal leaf bud galls on Eucalyptus (Myrtaceae) in south-eastern Australia

Zootaxa ◽  
2011 ◽  
Vol 3112 (1) ◽  
pp. 36 ◽  
Author(s):  
LEIGH A. NELSON ◽  
SONJA J. SCHEFFER ◽  
DAVID K. YEATES
Keyword(s):  
New Species ◽  
Host Specificity ◽  
Species Complex ◽  
The Other ◽  
Adult Size ◽  
Dorsal Shield ◽  
South Eastern ◽  
Eastern Australia ◽  
Three New Species ◽  
South Eastern Australia

Three new species of Fergusonina (Diptera: Fergusoninidae) flies are described from terminal leaf bud galls on Eucalyptus L'Hér. from south eastern Australia. Fergusonina omlandi Nelson and Yeates sp. nov. is the first species of fly from the genus Fergusonina to be described from the Eucalyptus pauciflora Sieb. ex Spreng. (Snow Gum) species complex; although another two species occur in sympatry on this host at higher elevations. Fergusonina omlandi sp. nov. can be distinguished from the latter by differences in adult size and markings on the mesonotum and morphology of the dorsal shield of the larva. The other new species, Fergusonina williamensis Nelson and Yeates sp. nov. and Fergusonina thornhilli Nelson and Yeates sp. nov. are the first flies to be described from Eucalyptus baxteri (Benth.) Maiden & Blakely and Eucalyptus dalrympleana Maiden, respectively. These two species can be distinguished from all other described Fergusonina by host specificity, adult colour and setation and morphology of the dorsal shield.

Systematics of the Egernia whitii species group (Lacertilia : Scincidae) in south-eastern Australia

2002 ◽  
Vol 50 (5) ◽  
pp. 439 ◽  
Author(s):  
Stephen C. Donnellan ◽  
Mark N. Hutchinson ◽  
Paula Dempsey ◽  
William S. Osborne
Keyword(s):  
Sensu Stricto ◽  
Species Group ◽  
The Other ◽  
Colour Pattern ◽  
Morphological Evidence ◽  
South Eastern ◽  
South Wales ◽  
Eastern Australia ◽  
Allelic Differences ◽  
South Eastern Australia

Allozyme electrophoresis was used to assess the taxonomic significance of colour pattern variation within and between populations of the Egernia whitii species group from 41 locations in south-eastern Australia. Analysis of the products of 39 presumed loci revealed that a minimum of three species are present in southern New South Wales among populations previously referred to Egernia whitii. Fixed allelic differences were maintained where pairs of species were sympatric. One of these three species is wide-ranging and is the one to which the name E. whitii is properly applied. The other two are more restricted ecologically and geographically and are described here as new. The three species are genetically and morphologically distinct from the other three eastern Australian members of the species group, E.�margaretae, E. modesta, and E. multiscutata. Genetic data and a review of the morphological evidence provide no support for the recognition of subspecies within either E. whitii (sensu stricto) or E. multiscutata.

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