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.

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.

CHEMICAL COMPOSITION AND IN VITRO DIGESTIBILITY OF RANGE FORAGE PLANTS OF THE STIPA-BOUTELOUA PRAIRIE

1967 ◽  
Vol 47 (2) ◽  
pp. 161-167 ◽  
Author(s):  
S. Smoliak ◽  
L. M. Bezeau
Keyword(s):  
Crude Protein ◽  
Nutritive Value ◽  
Calcium Content ◽  
Early Spring ◽  
In Vitro Digestibility ◽  
Native Grasses ◽  
Stages Of Growth ◽  
Artemisia Species ◽  
Shrubby Species

Five native grasses and one sedge of the Stipa-Bouteloua prairie, three introduced grasses collected at five stages of growth, and four shrubby species collected at three stages of growth were analyzed for proximate chemical constituents.The amounts of phosphorus and digestible and crude protein of all species decreased with maturity, while the cellulose increased. Introduced grasses generally contained more crude protein than native grasses. Shrubby species were higher in crude protein and phosphorus than native grasses. No consistent trend was observed in relative total ash and calcium content at progressive stages of development. The estimated nutritive value index was high for all grasses and low for two Artemisia species. The seasonal declines in crude protein and phosphorus suggest that protein and phosphorus supplements are desirable for range cattle during the fall, winter, and early spring.

Tree lines

1989 ◽  
Vol 324 (1223) ◽  
pp. 233-245 ◽  
Keyword(s):  
Growing Season ◽  
Early Spring ◽  
Summer Temperature ◽  
Northern Europe ◽  
Late Winter ◽  
Controlled Environment ◽  
Cold Climates ◽  
Tree Line ◽  
The Mean ◽  
Boreal Period

Trees do not generally grow in places where the mean temperature of the warmest month is less than about 10 °C. At their limit, trees are often short and crooked, the condition known as krummholz ; and the transition from tall forest to dwarf shrubby vegetation is often abrupt, forming a distinct tree line. Tree lines fluctuate with climatic change. There is compelling evidence to suggest that they shift to higher elevations and higher latitudes in warmer periods. In northern Europe, they were about 200 m higher in the Boreal period when the temperature is believed to have been 2 °C warmer than now. Controlled-environment studies and tree-ring evidence also point to considerable sensitivity of growth at the tree line to fluctuations in the summer temperature. Forest vegetation differs aerodynamically from dwarf vegetation in being aerodynamically rough. Consequently, the temperatures of above-ground tissues are closely coupled to temperatures of the air. In contrast, shorter vegetation experiences tissue temperatures and microclimates that depend substantially on other climatological variables, notably radiation and wind speed. Short vegetation is, on average, warmer than the air; this is the main reason why dwarf shrubs can succeed in cold climates where trees fail to grow and reproduce. Water stress commonly occurs in late winter and early spring when soil water is frozen. The foliage of trees at the tree line displays an inability to restrict water loss, either because the epidermis is damaged by abrasion or because the cuticle does not properly develop in the reduced growing season. Consequently, the longevity of leaves is reduced. Winter damage to trees is also likely as a result of gales and the deposition of ice in the canopy, both of which break branches and may contribute to the generally misshapen form of the crown.

Nitrogen fertiliser use on rain-fed pasture in the Mt Lofty Ranges, SouthAustralia. 2. Responses of perennial grasses, Tama ryegrass, andsod-sown oats to nitrogen fertiliser and cutting frequency

2003 ◽  
Vol 43 (6) ◽  
pp. 579 ◽  
Author(s):  
D. E. Elliott ◽  
R. J. Abbott
Keyword(s):  
Perennial Ryegrass ◽  
South Australia ◽  
Subterranean Clover ◽  
Perennial Grasses ◽  
Late Winter ◽  
Nitrogen Fertiliser ◽  
Cutting Frequency ◽  
Series Of Experiments ◽  
Fertiliser Application ◽  
Autumn And Winter

Two series of experiments were conducted in the Mt Lofty Ranges, South Australia, to examine, in a grass–subterranean clover pasture, the contribution of the companion grass to herbage mass and the responsiveness to the application of nitrogen (N) fertiliser. The first study examined the responsiveness, to a single rate of N, of grass–clover pastures containing either Tama ryegrass, sod-sown oats or 1 of 4 perennial grasses, viz. Victorian perennial ryegrass, Demeter fescue, Currie cocksfoot or Australian phalaris. These were compared in 2 experiments, under 3��different cutting frequencies at 3 periods during the growing season. In the other study, consisting of 12�experiments, the response to increasing rate of N fertiliser application of sod-sown oats or the existing pasture were compared over a 3-month period following N fertiliser application in autumn.In autumn and winter, all pastures responded significantly to N fertiliser, whereas in spring, the proportion of clover in each pasture and its growth determined whether or not there was a response to N fertiliser. Clover composition of pastures declined with N application, but clover was not eliminated from swards by application of 210 kg N/ha a year. In both series of experiments, pastures that established well with a high density of sod-sown oats out-yielded all other pastures in autumn and winter, whether the swards were unfertilised or received regular N fertiliser applications. In late winter, pastures sod-sown with Tama ryegrass yielded as well as the pasture sod-sown with oats, and enhanced spring growth significantly compared with perennial ryegrass. However, spring production of Tama ryegrass was poorer than that of perennial ryegrass, and overall no increase in annual production occurred. Of the perennial grasses, the highest yielding when N fertiliser was applied were Currie cocksfoot and perennial ryegrass (yielding in autumn), phalaris (winter), and perennial ryegrass and Demeter fescue (spring). Increased cutting frequency depressed the herbage mass response to N fertiliser following the initial application, but increased herbage N concentration of all pastures and also increased the final clover composition of N-fertilised pasture of 4�pasture types.

scholarly journals Tillering dynamics in spring and summer of marandu palisade grass pastures previously used under deferred grazing

2021 ◽  
Vol 73 (6) ◽  
pp. 1422-1430
Author(s):  
B.H.R. Carvalho ◽  
J.A. Martuscello ◽  
G.O. Rocha ◽  
N.A.M. Silva ◽  
G.S. Borges ◽  
...  
Keyword(s):  
Stability Index ◽  
Growing Season ◽  
Experimental Period ◽  
Early Spring ◽  
Late Winter ◽  
Population Stability ◽  
Brachiaria Brizantha ◽  
Appearance Rate ◽  
High Forage ◽  
Tiller Mortality

ABSTRACT This work was conducted to evaluate the effect of deferred pasture condition of Brachiaria brizantha cv. Marandu in the late winter on tillering during the growing season. The treatments were three pasture conditions at late winter: short pasture, tall pasture and tall/mown pasture. In September and October, tiller appearance rate (TApR) and tiller mortality rate (TMoR) were greater in the tall/mown pasture. In November and December, tall pasture presented greater TApR. From November to January the TMoR was greater in the tall pasture. The tiller stability index of short and tall/mown pastures were greater in October. The short pasture presented a greater tiller number than the tall and tall/mown pastures during the entire experimental period. Deferred and short pasture of marandu palisade grass at late winter presents in general lower tiller mortality and higher population density of tillers from the early spring onwards, in comparison to tall pasture. The mowing of marandu palisade grass with high forage mass at the late winter, although it only temporarily compromises the population stability of tillers, also stimulates its fast tillering from spring on.

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.

Weather conditions associated with grape production in the Okanagan Valley of British Columbia and potential impact of climate change

2002 ◽  
Vol 82 (4) ◽  
pp. 755-763 ◽  
Author(s):  
J. M. Caprio ◽  
H. A. Quamme
Keyword(s):  
Climate Change ◽  
British Columbia ◽  
Weather Conditions ◽  
Growing Season ◽  
Early Spring ◽  
Late Winter ◽  
Vitis Vinifera L ◽  
Flower Bud ◽  
Harvest Year ◽  
Okanagan Valley

An iterative χ2 method applied to 60 yr of records in the Okanagan Valley of British Columbia (1930–1989) revealed that the main climatic factor limiting grape production (Vitis spp. and Vitis vinifera L.) was low temperatures (critical value range, ≤–6°C to ≤–23°C) occurring during late October, November, December and February. Daytime temperatures ≤–9°C during late November and early December benefited grape production, probably because it prevented vine de-acclimation. Detrimental effects of precipitation during late October were probably associated with the early movement of Arctic fronts into the region. Beneficial effects of precipitation in the form of snow were observed in January. During the pre-harvest growing season, except for a 2-wk period in July, high temperatures (≥26°C) were associated with good production, probably because warm temperatures are required for flower bud initiation and development. In contrast, higher-than-normal temperatures were not beneficial to production during the harvest year. Detrimental effects of high temperature were observed during July of the pre-harvest year and July (≥32°C) and early August of the harvest year (≥28°C). During the growing season, rainfall was sometimes unfavourable for grape production under irrigation, either because of associated cool weather or greater disease occurrence. Both temperature and precipitation were greater in the last 18 yr of the study than the prior 36 yr, especially during the late winter and early spring. The anticipated climatic change appears to favour grape production in the Okanagan Valley. Key words: grape, climate change, heat stress, winter injury

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.

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.

Determination of the effects of temperature on viability, metabolic activity and proliferation of two Perkinsus species, and its significance to understanding seasonal cycles of perkinsosis

Parasitology ◽  
2008 ◽  
Vol 135 (4) ◽  
pp. 505-519 ◽  
Author(s):  
M. K. LA PEYRE ◽  
S. M. CASAS ◽  
A. VILLALBA ◽  
J. F. LA PEYRE
Keyword(s):  
Metabolic Activity ◽  
Early Spring ◽  
Parasite Infection ◽  
Late Winter ◽  
Seasonal Cycles ◽  
Perkinsus Marinus ◽  
Active Process ◽  
Effects Of Temperature

SUMMARYThe range of water temperatures in which Perkinsus species can survive and proliferate remains ill-defined, particularly at lower temperatures. The in vitro viability, metabolic activity, and proliferation of 3 isolates each of P. marinus and P. olseni trophozoites at 28°C, and at 15 and 4°C, after transfer from 28°C, were compared. Both species showed declines in metabolic activity and proliferation from 28°C to 15°C. At 4°C, both species had viability after 30 days incubation time (P. marinus 49%, P. olseni 58%), but limited metabolic activity and no proliferation. Perkinsus marinus viability was further compared when transferred directly from 28°C, 18°C and progressively from 18°C (0·5°C/day) to 2, 4 and 6°C and maintained for up to 4 months. Viability was highest under progressive transfer (77% and 54% after 30 and 60 days exposure to test temperatures). The decrease in P. marinus viability at the lower temperatures in vitro only partially explains decreasing parasite infection intensities in eastern oysters in the colder months of the year. Moreover, the significant decrease in parasite infection intensities in late winter and early spring, as temperatures increase, is likely due to an active process of elimination by oyster host defences.

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