Seasonal response of pasture to nitrogen fertilizer in the Mt. Lofty Ranges, South Australia

1975 ◽  
Vol 15 (73) ◽  
pp. 231 ◽  
Author(s):  
DE Elliot ◽  
AL Clarke
Keyword(s):  
Lolium Perenne ◽  
Nitrogen Loss ◽  
South Australia ◽  
Dactylis Glomerata ◽  
Trifolium Subterraneum ◽  
Early Spring ◽  
Late Winter ◽  
Potential Growth ◽  
A Site ◽  
Pasture Yield

Ammonium nitrate (0 to 200 kg ha-1 N) was applied to new areas of pure grass (Lolium perenne and Dactylis glomerata) and of mixed clover and grass (Trifolium subterraneum, L. perenne and D. glomerata) at monthly intervals from autumn (April) to late winter (August.) at a site in the Mt. Lofty Ranges, South Australia, and the pasture harvested 1 and 2 months after each application. As fertilizer applications were delayed, pasture yield responded increasingly to nitrogen. When 100 kg ha-1 was applied to grass, yield increases measured 2 months later ranged from 2 to 25 kg D.M. kg-1 N for the May and August applications respectively. Mixed pasture was less responsive than grass to later applications, because nitrogen suppressed the increasingly vigorous clover growth ; with 100 kg ha-1 N, response 2 months after the August application was 16 kg D.M. kg-1 N. Applied nitrate and ammonium disappeared rapidly from the top 30 cm of soil. Only after the May and June dressings, when rainfall was light, did significant quantities persist for one month. Some of the nitrogen loss was from leaching. Herbage harvested after two months accounted for 17 to 48 per cent of nitrogen applied at 100 kg ha-1, the largest recovery following the July dressing. The relatively small responses to high rates of nitrogen in mid winter indicate that other factors, possibly light energy, limited the potential growth of the pasture. The results suggest that nitrogen could be used either to increase the supply of grazing in early spring or the production of hay in late spring, especially where pastures lack clover.

Control of the biennial thistle, Onopordum, by amitrole and five perennial grasses

1968 ◽  
Vol 8 (32) ◽  
pp. 332 ◽  
Author(s):  
PW Michael
Keyword(s):  
Lolium Perenne ◽  
Festuca Arundinacea ◽  
Relative Effectiveness ◽  
Dactylis Glomerata ◽  
Trifolium Subterraneum ◽  
Perennial Grasses ◽  
South Wales ◽  
Distribution Studies ◽  
Apparent Susceptibility

Experiments carried out from 1959 to 1967 Rear Goulburn in the southern tablelands of New South Wales were designed to test the relative effectiveness of the perennial grasses, Bromtls inermis C.P.I.7073, Dactylis glomerata CV. Brignoles, Festuca arumdinacea CV. Demeter, Lolium perenne CV. Victorian, and Phalaris tuberosa CV. Australian in seasonal control of the biennial thistle Onopordum. The grasses were sown in autumn and in spring. Amitrole (0.5 lb active ingredient an acre) was used to suppress the thistles in the first season. Harvests of the autumn- and spring-sown plots in December 1959 showed large decreases in yield of thistles and increases in yield of grass due to spraying, but in two or three years these effects had disappeared. Dactylis glomerata and Lolium perenne were the most productive grasses at the December 1959 harvest, but the former gave better thistle control. Harvests of the autumn-sown plots in October 1963 showed that Dactylis glomerata and Festuca arundinacea gave the best control of thistles, while in 1966 Dactylis glomerata had almost disappeared and was no longer effective. In 1966, Festuca arumdinacea and Phalaris tuberosa were the only grasses giving effective thistle control. Harvests of the autumn-sown plots in October 1960 showed an increase in yield of the sown grasses but not of the thistles to 30 and 60 lb nitrogen applied in August 1960 before active spring growth of thistles began. Despite a stronger growth of thistles in the first season, the spring-sown grasses showed essentially the same pattern of thistle control as the autumn-sown grasses throughout the remainder of the trial period. Root distribution studies in 1961 showed that Dactylis glomerata had a much higher proportion of its roots in the top six inches than either Festuca arundinacea or Phalaris tuberosa. The greater surface rooting habit of Dactylis glomerata was considered to be important in determining its early success in thistle control, its exclusion of Trifolium subterraneum and its apparent susceptibility to a drought experienced in 1964-65. On the other hand, the deeper rooting habit of Festuca arundinacea and Phalaris tuberosa was taken to explain their persistence and long-term success in thistle control.

Root-knot nematode (Meloidogyne hapla) on potato in south-eastern South Australia

1985 ◽  
Vol 25 (2) ◽  
pp. 455 ◽  
Author(s):  
GR Stirling ◽  
MF Wachtel
Keyword(s):  
Potato Crop ◽  
South Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Late Winter ◽  
Meloidogyne Hapla ◽  
Root Knot Nematode ◽  
Alternate Host ◽  
South Eastern ◽  
Potato Crops

In south-eastern South Australia root-knot nematode (Meloidogyne hapla) caused losses to potato crops in fields that were sown once every 5- 15 years and were used for grazing in the intervening years. Although seed used by some growers was infested with M. hapla, the nematode also survived between potato crops on subterranean clover (Trifolium subterraneum), the dominant pasture species, and capeweed (Cryptostemma calendula). Subterranean clover was the most abundant alternate host. Nematodes invaded clover seedlings that established following rain in April and produced eggs about 12 weeks later. A second generation was produced in late winter and spring, so that a relatively high root-knot nematode population was present when potatoes were planted. The population increased rapidly on potatoes and numbers capable of causing severe root damage were observed 10- 15 weeks after planting. The growing of non-host crops, or the use of herbicides or cultivation to eliminate subterranean clover in the winter prior to the potato crop, should be investigated. In a nematicide trial, ethylene dibromide at 70 and 110 kg/ha increased yields of potato cv. Pontiac by about 90%.

scholarly journals Snow chemistry of Agassiz Ice Cap, Ellesmere Island, Northwest Territories, Canada

1997 ◽  
Vol 43 (144) ◽  
pp. 199-206 ◽  
Author(s):  
Kumiko Goto-Azuma ◽  
Roy M. Koerner ◽  
Masayoshi Nakawo ◽  
Akira Kudo
Keyword(s):  
Northwest Territories ◽  
Local Area ◽  
Early Spring ◽  
Snow Accumulation ◽  
Photochemical Reactions ◽  
Ellesmere Island ◽  
Late Winter ◽  
Snow Chemistry ◽  
Ice Cap ◽  
A Site

AbstractPit-wall samples were collected from two sites about 2 km apart on Agassiz Ice Cap, Ellesmere Island, Northwest Territories, Canada, in 1992, 1993 and 1994, and from a site a further 1 km distant, in order to study spatial and seasonal variations in snow chemistry. Two of the pits were dug in wind-scoured zones and one in an unscoured zone. Although a large part of the winter snow is removed from the scoured zones (which do not show very negativeδ18O values) the winter/spring anion peaks are still evident; this may be due to the predominance of dry deposition in mid-winter. The Cl−and SO42–ions peak in late winter/early spring, while NO3−peaks both in late winter/early spring and in summer. Vertical concentration profiles of all anions did not significantly alter over a 2 year period, indicating that there are no serious post-depositional changes due to evaporation, snow melting or photochemical reactions. However, comparisons between stake/board snow-accumulation measurements and those derived from the least scoured pit indicate that a single pit will represent annual accumulation rates for a local area only.

Digestibility and voluntary intake measurements on regrowths of six Tasmanian pasture species

1973 ◽  
Vol 13 (61) ◽  
pp. 158 ◽  
Author(s):  
PJ Michell
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Dactylis Glomerata ◽  
Early Spring ◽  
Late Spring ◽  
Pure Species ◽  
Short Rotation ◽  
Voluntary Intake ◽  
Autumn And Winter

Pure species swards of Trifolium repens (white clover cv. Grasslands Huia), Lolium perenne (perennial ryegrass cv. Tasmanian No. I ) , Lolium perenne x L. multiflorum (short rotation ryegrass cv. Grasslands Manawa), Lolium perenne (long rotation ryegrass cv. Grasslands Ariki), Dactylis glomerata (cocksfoot cv. Currie) and Dactylis glomerata (cocksfoot cv. Grasslands Apanui) were mechanically cut in May, August, September-October, and November 1969, and January, March, May, and August 1970. The material from these cuts was artificially dried, and digestibilities and voluntary intakes measured using penned sheep. Overall, the digestibility and voluntary intake of white clover was significantly higher (P < 0.05) than that of any of the grasses, the digestibility of Apanui cocksfoot was significantly lower (P < 0.05) than that of the ryegrasses and there were no significant differences (P < 0.05) between the intakes of the various grasses. Under the management system used, the digestibility of the grasses remained relatively stable over the summer, autumn and winter, rose to a peak in early spring and fell in late spring after ear emergence. The digestibility of white clover remained high over the winter and early spring and declined slowly over the summer. The voluntary intakes of all the species were at their lowest levels in the winter, rose to a peak in the spring, fell in the late spring to a stable level over the summer, and fell again in the autumn. At any digestibility level, the intake of spring-summer cut pasture was approximately 20 per cent higher than that of winter cut pasture. The intake of autumn cut pasture was intermediate. The overall relation between intake (I) and digestibility (D) was I = 1.06D + 2.7 � 8.4 (P < 0.01). Within the spring-summer cuts, the relation was I = 1.01 D + 14.6 � 4.0 (P < 0.01) and within the winter cuts it was I = 1.08D - 5.9 � 4.1 (P < 0.01).

Pollen vectors and pollination of faba beans in southern Australia

1991 ◽  
Vol 42 (7) ◽  
pp. 1173 ◽  
Author(s):  
FL Stoddard
Keyword(s):  
Vicia Faba ◽  
Mediterranean Climate ◽  
South Australia ◽  
Early Spring ◽  
Late Winter ◽  
Flower Visitors ◽  
Vicia Faba L ◽  
Faba Beans ◽  
Pollen Vectors ◽  
Western Victoria

Commercial crops of faba beans (Vicia faba L.) in South Australia and western Victoria were surveyed for flower visitors and incidence of pollination. Honeybees were the only pollen vectors. The incidence of pollination was never less than 50% and averaged 80%. The effectiveness of honeybees as pollen vectors contrasts with their ineffectiveness in colder climates, partly because in the Mediterranean climate beans flower in late winter and early spring when bees are in search of pollen. It is unlikely that growers of faba beans in Australia will need to provide supplementary hives to ensure adequate pollination.

Snow chemistry of Agassiz Ice Cap, Ellesmere Island, Northwest Territories, Canada

1997 ◽  
Vol 43 (144) ◽  
pp. 199-206 ◽  
Author(s):  
Kumiko Goto-Azuma ◽  
Roy M. Koerner ◽  
Masayoshi Nakawo ◽  
Akira Kudo
Keyword(s):  
Northwest Territories ◽  
Local Area ◽  
Early Spring ◽  
Snow Accumulation ◽  
Photochemical Reactions ◽  
Ellesmere Island ◽  
Late Winter ◽  
Snow Chemistry ◽  
Ice Cap ◽  
A Site

AbstractPit-wall samples were collected from two sites about 2 km apart on Agassiz Ice Cap, Ellesmere Island, Northwest Territories, Canada, in 1992, 1993 and 1994, and from a site a further 1 km distant, in order to study spatial and seasonal variations in snow chemistry. Two of the pits were dug in wind-scoured zones and one in an unscoured zone. Although a large part of the winter snow is removed from the scoured zones (which do not show very negative δ18O values) the winter/spring anion peaks are still evident; this may be due to the predominance of dry deposition in mid-winter. The Cl− and SO42– ions peak in late winter/early spring, while NO3− peaks both in late winter/early spring and in summer. Vertical concentration profiles of all anions did not significantly alter over a 2 year period, indicating that there are no serious post-depositional changes due to evaporation, snow melting or photochemical reactions. However, comparisons between stake/board snow-accumulation measurements and those derived from the least scoured pit indicate that a single pit will represent annual accumulation rates for a local area only.

The long-tailed mealybug, Pseudococcus adonidum (L.) in South Australia

1959 ◽  
Vol 10 (3) ◽  
pp. 322 ◽  
Author(s):  
TO Browning
Keyword(s):  
South Australia ◽  
Regular Sequence ◽  
Reproductive Rate ◽  
Early Spring ◽  
Behaviour Pattern ◽  
Late Winter ◽  
Spider Webs ◽  
Predatory Insects ◽  
New Generation ◽  
Orange Trees

The numbers of the long-tailed mealybug, P. adonidum (L.), on irrigated orange trees in South Australia rise and fall in a fairly regular sequence throughout the year. They are always low in summer, rise in autumn and early winter, and begin to fall gradually in late winter and spring. There is a sudden sharp rise in November followed almost at once by an equally sharp fall to the numbers characteristic of summer. This sequence may be explained in terms of the influence of weather on the survival and multiplication of the mealybugs in relation to the place where they happen to be living, the influence of predatory insects, and the behaviour pattern of the species. Food seems to play no part in this sequence except as its quality may influence behaviour. During summer the majority of the mealybugs on the leaves are to be found in specially sheltered places, such as under spider webs. There is evidence that the special quality of these places that makes them suitable for mealybugs is the greater humidity there than elsewhere. Young mealybugs on hatching are active in summer and tend to leave the shelter in which they originated and are likely to perish before they find another suitable place. At this time there are relatively few predatory insects. As autumn approaches the becomes cooler and less desiccating, and although the reproductive rate may fall the chance that young mealybugs will survive increases. This continues until the cold of winter reduces the reproductive rate to the point where it can no longer compensate for deaths and the population begins to fall. At the same time predatory insects become more numerous and take a greater toll of the population, forcing numbers still further down. In early spring the insects stop feeding and seek a sheltered place in which to reproduce. The migration from the leaves to the trunk and ground gathers momentum during September and October until the numbers left on the leaves are very low. At this time predatory insects become more numerous than they have been and the numbers of sheltering mealybugs may be greatly reduced. Then in November a new generation is produced which invades the leaves but most of these are killed quite soon by the hot dry winds which are common at this time of the year. The population falls to a low level and remains so until autumn.

Mouse plagues in South Australia cereal-growing areas III. Changes in mouse abundance during plague and non-plague years, and the role of refugia

1991 ◽  
Vol 18 (5) ◽  
pp. 593 ◽  
Author(s):  
GJ Mutze
Keyword(s):  
Survival Rates ◽  
South Australia ◽  
Breeding Population ◽  
Early Spring ◽  
Late Spring ◽  
Late Winter ◽  
Population Declines ◽  
Population Changes ◽  
Railway Line ◽  
Large Numbers

Mouse populations were monitored at 15 sites between 1980 and 1990, during which time one severe mouse plague, in 1980, and one minor outbreak, in 1984, were recorded. Smaller annual peaks in autumn to early winter were followed by winter population declines. Crops were colonised each year in late winter or early spring by mice from winter refuge habitats with dense, low vegetation, including roadsides and grassland along a railway line. In most years mouse numbers in crops declined during summer, but in 1983-84 they rose continuously during summer and autumn, and reached very high levels. Crops planted in 1984 were invaded by large numbers of mice which had survived through winter in the paddocks, but population levels again crashed in late spring and summer. Recorded population changes were generally consistent with plague probabilities predicted from environmental variables, except in 1985 when numbers failed to reach the predicted high levels at most sites. Population changes in crops during late spring appear to be critical in the development of mouse plagues. Large litter sizes and pregnancy rates, and variable survival rates and size of the breeding population, appear to be important factors at that time.

Nitrogen fertiliser use on rain-fed pasture in the Mt Lofty Ranges, South Australia. 1. Pasture mass, composition and nutritive characteristics

2003 ◽  
Vol 43 (6) ◽  
pp. 553 ◽  
Author(s):  
D. E. Elliott ◽  
R. J. Abbott
Keyword(s):  
South Australia ◽  
Growing Season ◽  
Early Spring ◽  
Late Spring ◽  
Late Winter ◽  
In Vitro Digestibility ◽  
Single Application ◽  
Nitrogen Fertiliser ◽  
N Rates

The effects of nitrogen (N) fertiliser (0–200 kg/ha) on mass, botanical composition, and N concentration (%) in herbage were examined in nine 2- or 3-year rate × time of application experiments, 14 single-year annual rate of application experiments and 15 short-term spring rate of application experiments, at 27 sites in the Mt Lofty Ranges, South Australia, in 7 years between 1970 and 1979, inclusive. Effects on in vitro digestibility and concentrations of other nutrients in herbage were examined in selected experiments.Annual applications of 200 kg N/ha increased herbage mass by an average of 2.8 t/ha (57% increase), over the average yield of unfertilised pasture of 4.6 t/ha. Subterranean clover was eliminated from the sward with this rate of N application, although this may have been exacerbated by the experimental methods used. N fertiliser application increased herbage mass throughout the growing season, except in autumn 1972 when low rainfall restricted growth and about half of the experiments were not harvested. In 5 of the 126 individual harvests, herbage mass did not respond positively to N fertiliser applications, even though clover composition of herbage declined.A single application of 50 kg N/ha in autumn increased herbage mass, 6–8 weeks later, by an average 11�kg�DM/kg N, but this N effect only persisted to a subsequent harvest in about half of the experiments, with an average residual effect of 25%. Commonly, a response to N fertiliser in the first and/or second harvests was followed by a non-responsive period and then a depression in herbage mass, where no further N fertiliser was applied. With repeated N fertiliser applications, the average responses to 50� kg� N/ha were 11 kg DM/kg N in late winter and also in early spring, similar to the autumn response, and 18�kg�DM/kg N in late spring. In a later study, a single application of 50 kg N/ha in spring, for silage or hay conservation, increased herbage mass by an average of 1.3 t/ha in late spring while the average response to 100 kg N/ha was 2.0 t/ha. Clover composition declined but was rarely eliminated from the sward by these N rates when applied only in spring.From early winter to early spring, N concentration in herbage from unfertilised pasture ranged from 3 to 4% N and then progressively declined. Relationships between herbage N concentrations and increasing N rates were either linear or curvilinear in early and late winter, whereas in spring, many of these responses to N fertiliser were sigmoidal, with a decline in herbage N concentrations being observed at low N rates. Nitrogen fertiliser applied throughout the growing season had little effect on in vitro digestibility for a wide range of pasture compositions. However, in vitro digestibility of a pure grass pasture was increased early in the growing season by applications up to 50 kg N/ha, but was depressed by the same N rates applied in late spring. Consistently, an increase in N had the following effect on the concentration of other herbage nutrients: K�increased; Ca decreased becoming more pronounced as the growing season progressed; P decreased in late spring; and Cu fell in autumn. The content of these nutrients in harvested herbage usually increased with increasing N rate, particularly when associated with large herbage mass responses to N fertiliser. The K : (Ca + Mg) ratio in herbage, a criterion for grass tetany, increased detrimentally with increasing N rate. Strategies are proposed for using N fertiliser on rain-fed pasture in the Mt Lofty Ranges.

Factors affecting competition between subterranean clover and a barley cover crop

1973 ◽  
Vol 13 (60) ◽  
pp. 56 ◽  
Author(s):  
AA McGowan ◽  
WA Williams
Keyword(s):  
Seed Production ◽  
Light Transmission ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Early Spring ◽  
Late Winter ◽  
Factors Affecting ◽  
Competition For Light ◽  
Clover Seed ◽  
Main Factor

Subterranean clover (Trifolium subterraneum) was sown with barley (Hordeum vulgare) in autumn under a variety of management treatments. Clover seed production was increased when barley emergence was delayed by seed treatment with CCC or paraffin wax, or by delayed sowing, when barley seeding rates were reduced, or when barley was clipped in late winter. The main factor limiting growth of the undersown clover was competition for light, especially in late winter and early spring when light transmission through the barley crop dropped below 60 per cent. Despite a dry spring, interspecific competition for moisture evidently imposed very little restriction on clover growth and seed production. Competition for nitrogen may have occurred earlier in the season.

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