A preliminary report on selenium and animal health in Western Australia

1962 ◽  
Vol 2 (7) ◽  
pp. 261 ◽  
Author(s):  
MR Gardiner ◽  
J Armstrong ◽  
H Fels ◽  
RN Glencross
Keyword(s):  
Western Australia ◽  
Animal Health ◽  
Agricultural Practices ◽  
Subterranean Clover ◽  
Selenium Deficiency ◽  
Early Spring ◽  
Muscle Disease ◽  
Late Winter ◽  
Growth Stages ◽  
Two Peaks

White muscle disease in Western Australia appears to be a sporadic disease, fundamentally related to selenium deficiency but in the main limited to young sheep subjected to other concurrent stresses. Whether the complicating stress condition acts primarily at a nutritional level or whether if affects associated endocrine or metabolic pathway is uncertain from present evidence, although it is possible that both mechanisms may be involved. The disease is restricted to the southwestern agricultural districts, having rainfalls of greater than 20 inches. A much greater than average rainfall during the early winter growth stages of subterranean clover, followed a dry August and September, was common to both years (1960 and 1961) during which WMD was first widely recognized and may be ecologically significant in winter outbreaks. There are two peaks of incidence--one in late winter and early spring, affecting young lambs running mainly on subclover pastures, and the other in the summer, affecting weaners and hoggets fed cereal stubble, hay and grain. A survey of these feeds suggests that tehy are very often low in selenium, and may frequently contain less than 0.03 p.p.m. (dry matter) which is proposed as a critical level. However, many flocks grazing pastures containing less than this amount of selenium appear healthy. Ten trials were carried out in the affected area in 1960-61 to test the effect of selenium on lamb or weaner rate of growth Only one trial produced evidence of a significant response although one other suggested that an improvement had taken place. Five trials to determine the value of selenium in improving ewe fertility and early lamb survival were also conducted. The. results of two of them suggested that some improvement could be achieved. Vitamin E also appeared useful in the fertility trials. The soil and plant selenium backgrounds, insofar as thy are known in Western Australia, are discussed in relation to the pattern of outbreaks. Certain factors in the changing agricultural practices are mentioned as probable contributors, notably an increase in sheep stocking rates and heavier application of superphosphate.

Further observations on plant selenium levels in Western Australia

1963 ◽  
Vol 3 (11) ◽  
pp. 284 ◽  
Author(s):  
MR Gardiner ◽  
RC Gorman
Keyword(s):  
Western Australia ◽  
White Muscle ◽  
Critical Level ◽  
Subterranean Clover ◽  
Selenium Deficiency ◽  
Muscle Disease ◽  
Annual Rainfall ◽  
Botanical Composition ◽  
White Muscle Disease ◽  
Significant Difference

A survey of plant selenium was carried out in the agricultural district of Western Australia in the spring of 1962. Pasture samples were collected from mid-August to mid-November during, or shortly after, the spring flush of growth in the different districts. Pastures were collected from both 'light' and 'heavy' country in each of the districts, and whenever possible, fertilizer history was recorded and botanical composition determined. Pasture samples from the 10-15 inch rainfall belt averaged 0.26 p.p.m. selenium ; from the 15-20 inch rainfall belt, 0.08 p.p.m., from the 21-30 inch rainfall belt, 0.056 3.p.m ; and from the higher than 30 inch belt, 0.036 p.p.m. If the critical level for selenium deficiency syndromes is placed at 0.05 p.p.m., then deficiency levels mg appear in all rainfall belts, the lower limit of which is the 15 inch isobyet. Regression analyses showed that there was a significant difference between the selenium contents of pastures from heavy and light soils in each rainfall area. The indicator condition of selenium levels of 0.05 p.p.m or less (white muscle disease) has not been seen in the northern range of the higher rainfall districts, although here, as elsewhere, plant selenium levels appear to be predicated on mean annual rainfall figures and on type of county. Grasses and cereals tended to dominate the pastures in the areas with less than 15 inches of rainfall a-year, while subterranean clover with admixtures of capeweed and grasses were chiefly found in the higher rainfall districts.

Factors affecting the productivity of irrigated annual pastures. 1. Time of first irrigation in late summer-early autumn

1986 ◽  
Vol 26 (3) ◽  
pp. 297 ◽  
Author(s):  
CR Stockdale
Keyword(s):  
Nitrogen Content ◽  
Irrigation Treatment ◽  
Subterranean Clover ◽  
Late Summer ◽  
Early Spring ◽  
The Other ◽  
Late Winter ◽  
Factors Affecting ◽  
Autumn And Winter ◽  
Clover Content

The influence of time of first irrigation (mid-February, early March, or late March) on the productivity of an annual pasture was studied for 3 years in northern Victoria. Beginning the irrigation of annual pastures in late summer instead of at the normal time of late March- April provided additional herbage in autumn and winter and did not adversely affect herbage production in late winter-early spring; up to 2.3 t/ha DM of additional herbage was obtained by mid June and 4.3 t/ha DM over the whole season. Earlier irrigation also increased the subterranean clover content of the pasture, resulting in herbage that was lower in digestibility and higher in nitrogen content than that in the other treatments. The benefit of early irrigation in increasing clover content may be offset by invasion by weeds. In this experiment, a potential weed problem in the earliest irrigation treatment appeared at the beginning of year 3.

scholarly journals The long-term use of nitrogen fertiliser in intensive hill country farming

1993 ◽  
pp. 59-61
Author(s):  
D. Daniell
Keyword(s):  
Animal Health ◽  
Nitrogen Compound ◽  
Land Development ◽  
Cost Effective ◽  
Early Spring ◽  
Diammonium Phosphate ◽  
Late Winter ◽  
Hill Country ◽  
Supplementary Feed ◽  
Initial Objective

In 1969 the initial objective in using a nitrogen compound fertiliser was to bridge a feed deficit in late winter-early spring. Further advantages were observed, including an improvement in pastures from browntop to ryegrass dominance, better growth into dry summer, and faster recovery from droughts. Diammonium phosphate (DAP) was also incorporated into land development out of manuka, resulting in much faster establishment of dense pasture. Cost comparisons with superphosphate encouraged the use of DAP as an annual maintenance fertiliser from 1975, usually at a rate of 125 kg/ha. Details are given of sulphur additives, molybdenum, lime and copper for animal health. The lift in productivity from 1969 to 1992 is shown. The conclusion is that a DAP/ sulphur fertiliser applied from late autumn to early spring is a cost-effective and balanced input. It allows a high stocking rate (12/ha) on poorer hill country, without supplementary feed, plus high per head performance. Feed generated has been sufficient to shear 2100 ram hoggets in early August, culminating in ram sales of 1400 per year. Lambing percentages are above 130% survival to sale in good years, and wool weights have averaged 7.7 kg/year, including wool sold on sheeps' back. Ewe hoggets are mated, averaging 30% survival to sale. Keywords: diammonium phosphate, feed cover, fertiliser, hill country, land development

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.

scholarly journals Effect of Herbicides on the Management of the Invasive Weed Solanum rostratum Dunal (Solanaceae)

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 284
Author(s):  
Jackline Abu-Nassar ◽  
Maor Matzrafi
Keyword(s):  
Growth Stage ◽  
Late Summer ◽  
Early Spring ◽  
Growth Stages ◽  
Weed Species ◽  
Invasive Weed ◽  
Solanum Rostratum ◽  
Stage 4 ◽  
Chemical Solutions ◽  
Late Growth

Solanum rostratum Dunal is an invasive weed species that invaded Israel in the 1950s. The weed appears in several germination flashes, from early spring until late summer. Recently, an increase in its distribution range was observed, alongside the identification of new populations in the northern part of Israel. This study aimed to investigate the efficacy of herbicide application for the control of S. rostratum using two field populations originated from the Golan Heights and the Jezreel Valley. While minor differences in herbicide efficacy were recorded between populations, plant growth stage had a significant effect on herbicide response. Carfentrazone-ethyl was found to be highly effective in controlling plants at both early and late growth stages. Metribuzin, oxadiazon, oxyfluorfen and tembutrione showed reduced efficacy when applied at later growth stage (8–9 cm height), as compared to the application at an early growth stage (4–5 cm height). Tank mixes of oxadiazon and oxyfluorfen with different concentrations of surfactant improved later growth stage plant control. Taken together, our study highlights several herbicides that can improve weed control and may be used as chemical solutions alongside diversified crop rotation options. Thus, they may aid in preventing the spread and further buildup of S. rostratum field populations.

scholarly journals Potential for Mycorrhizae-Assisted Phytoremediation of Phosphorus for Improved Water Quality

2020 ◽  
Vol 18 (1) ◽  
pp. 7
Author(s):  
Jessica A. Rubin ◽  
Josef H. Görres
Keyword(s):  
Water Quality ◽  
Animal Health ◽  
Phosphorus Uptake ◽  
Agricultural Practices ◽  
Fold Increase ◽  
Landscape Patterns ◽  
Cyanobacterial Blooms ◽  
Terrestrial Plants ◽  
Source Reduction ◽  
Water Ecosystems

During this 6th Great Extinction, freshwater quality is imperiled by upland terrestrial practices. Phosphorus, a macronutrient critical for life, can be a concerning contaminant when excessively present in waterways due to its stimulation of algal and cyanobacterial blooms, with consequences for ecosystem functioning, water use, and human and animal health. Landscape patterns from residential, industrial and agricultural practices release phosphorus at alarming rates and concentrations threaten watershed communities. In an effort to reconcile the anthropogenic effects of phosphorus pollution, several strategies are available to land managers. These include source reduction, contamination event prevention and interception. A total of 80% of terrestrial plants host mycorrhizae which facilitate increased phosphorus uptake and thus removal from soil and water. This symbiotic relationship between fungi and plants facilitates a several-fold increase in phosphorus uptake. It is surprising how little this relationship has been encouraged to mitigate phosphorus for water quality improvement. This paper explores how facilitating this symbiosis in different landscape and land-use contexts can help reduce the application of fertility amendments, prevent non-point source leaching and erosion, and intercept remineralized phosphorus before it enters surface water ecosystems. This literature survey offers promising insights into how mycorrhizae can aid ecological restoration to reconcile humans’ damage to Earth’s freshwater. We also identify areas where research is needed.

Seasonal activity and estivation of lumbricid earthworms in the midlands of Tasmania

Soil Research ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1355 ◽  
Author(s):  
RB Garnsey
Keyword(s):  
Soil Moisture ◽  
Adult Development ◽  
Survival Rates ◽  
Soil Surface ◽  
Early Spring ◽  
Lumbricus Rubellus ◽  
Late Winter ◽  
Cocoon Production ◽  
Density And Biomass ◽  
Earthworm Activity

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.

TEMPERATURE RESISTANCE OF GOLDFISH MAINTAINED UNDER CONTROLLED PHOTOPERIODS

1959 ◽  
Vol 37 (4) ◽  
pp. 419-428 ◽  
Author(s):  
William S. Hoar ◽  
G. Beth Robertson
Keyword(s):  
Temperature Change ◽  
Seasonal Variations ◽  
Rapid Growth ◽  
Endocrine System ◽  
Early Spring ◽  
Late Winter ◽  
Thyroid Activity ◽  
Temperature Resistance ◽  
Sudden Temperature Change

Goldfish maintained under controlled photoperiods for 6 weeks or longer were relatively more resistant to a sudden elevation in temperature when the daily photoperiods had been long (16 hours) and relatively more resistant to sudden chilling when they had been short (8 hours). The magnitude of the effect varied with the season. Thyroid activity was slightly greater in fish maintained under the shorter photoperiods. The longer photoperiods stimulated more rapid growth of ovaries during late winter and early spring. The endocrine system is considered a link in the chain of events regulating seasonal variations in resistance to sudden temperature change.

Leaf spot and dry rot of lettuce caused by Xanthomonas vitians (Brown) Dowson

1963 ◽  
Vol 14 (6) ◽  
pp. 778 ◽  
Author(s):  
DE Harrison
Keyword(s):  
Leaf Spot ◽  
Early Spring ◽  
Late Winter ◽  
Laboratory Studies ◽  
Dry Rot ◽  
Complete Destruction ◽  
Western Victoria ◽  
Valley Area ◽  
North Western

During the late winter and early spring of 1960, and again to a lesser extent in 1961 and 1962, many lettuce crops in the Murray Valley area of north-western Victoria were seriously affected by a disease characterized by blackening, dry rotting, and collapse of the affected leaves. The incidence of disease varied from about 10% up to practically complete destruction of some plantings. A yellow bacterium was consistently isolated from affected plants and proved to be pathogenic to lettuce. Laboratory studies have shown that the organism agrees closely with the recorded description of Xanthomonas vitians (Brown) Dowson, which has not, apparently, been previously studied in Australia.

Insecticide sprays, natural enemy assemblages and predation on Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae)

2014 ◽  
Vol 104 (5) ◽  
pp. 576-585 ◽  
Author(s):  
C. Monzo ◽  
J.A. Qureshi ◽  
P.A. Stansly
Keyword(s):  
Natural Enemy ◽  
Early Spring ◽  
Citrus Greening ◽  
Asian Citrus Psyllid ◽  
Late Winter ◽  
Diaphorina Citri ◽  
Citrus Groves ◽  
Arthropod Fauna ◽  
Predator Exclusion ◽  
Insecticide Sprays

AbstractThe Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of ‘huanglongbing’ (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests.

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