Effect of time of application of herbicides on the long-term control of St. John's wort (Hypericum perforatum var. augustifolium)

1979 ◽  
Vol 19 (101) ◽  
pp. 746 ◽  
Author(s):  
MH Campbell ◽  
JJ Dellow ◽  
AR Gilmour

The effect of time of application of herbicides on the long-term control of St. John's wort was investigated at Tuena, New South Wales. The herbicides used were: 2,4-D, 2,4,5-T, 2,4-D -i- 2,4,5-T, picloram + 2,4-D, and glyphosate. Each of these was applied in February, May, August and November, 1976, and regrowth of wort monitored until February 1978. The percentage ground cover of unsprayed St. John's wort varied between 75% and 85% over the experimental period. Initially all herbicides reduced the ground cover of St. John's wort from over 75% to less than 15%. Thereafter the regrowth of wort depended on the long-term effect of the herbicides. At the final assessment in February 1978, the most effective herbicide treatments were: from the February and May applications, glyphosate and picloram + 2,4-D; from the August application, picloram + 2,4-D; and from the November application, picloram + 2,4-D, 2,4-D + 2,4,5-T and 2,4-D.


1991 ◽  
Vol 31 (4) ◽  
pp. 499 ◽  
Author(s):  
MH Campbell ◽  
BR Milne ◽  
JJ Dellow ◽  
HI Nicol

The effect of type of herbicide and time and rate of application on the reduction in ground cover of St John's wort (Hypericum perforatum L.) was determined at Orange, New South Wales. In January, April, July and November 1988, 8 herbicide treatments including the currently used glyphosate and picloram + 2,4-D were applied to vigorously growing H. perforaturn, and the reduction in percentage ground cover was recorded in December 1989. Ineffective herbicides (a.i./ha) were tebuthiuron, 0.8-6.4 kg; metsulfuron, 5-20 g; and paraquat + diquat, 0.4 + 0.5 kg. The addition of metsulfuron (2.5 g a.i./ha) to glyphosate (0.9 and 1.8 kg a.i./ha) did not increase the effectiveness of the latter. Effective herbicides (kg a.i./ha) were triclopyr + picloram, 0.6 + 0.2; picloram + 2,4-D, 0.2 + 0.8; glyphosate, 1.8; and triclopyr, 1.92. There was a strong trend for these herbicides to be more effective in January and November than in April and July. Based on price, effectiveness and selectivity, triclopyr + picloram would be preferred to the other herbicides for boom and spot spraying, and glyphosate would be the only herbicide suitable for aerial application prior to sowing improved pastures on non-arable land.



2004 ◽  
Vol 44 (3) ◽  
pp. 283 ◽  
Author(s):  
S. R. Murphy ◽  
G. M. Lodge ◽  
S. Harden

Surface runoff can represent a significant part of the hydrological balance of grazed pastures on the north-west slopes of New South Wales, and is influenced by a range of rainfall characteristic, soil property, and pasture conditions. Runoff plots were established on grazed pastures at 3 sites as part of the Sustainable Grazing Systems National Experiment (SGS NE). Pastures were either native (redgrass, wallaby grass and wire grass) or sown species (phalaris, subterranean clover and lucerne) and a range of grazing management treatments were imposed to manipulate pasture herbage mass, litter mass and ground cover. Rainfall and runoff events were recorded using automatic data loggers between January 1998 and September 2001. Stored soil water in the surface layer (0–22.5 cm) was monitored continuously using electrical resistance sensors and automatic loggers. Pasture herbage mass, litter mass and ground cover were estimated regularly to provide information useful in interpreting runoff generation processes.Total runoff ranged from 6.6 mm at Manilla (0.3% of rainfall) to 185 mm at Nundle (5.7% of rainfall) for different grazing treatments, with the largest runoff event being recorded at Nundle (46.7 mm). Combined site linear regression analyses showed that soil depth, rainfall depth and rainfall duration explained up to 30.3% of the variation in runoff depth. For individual sites, these same variables were also important, accounting for 13.3–33.6% of the variation in runoff depth. Continuous monitoring of stored soil water in relation to these runoff events indicated that the majority of these events were generated by saturation excess, with major events in winter contributing substantially to regional flooding. Long-term simulation modelling (1957–2001) using the SGS Pasture Model indicated that most runoff events were generated in summer, which concurred with the number of flood events recorded at Gunnedah, NSW, downstream of the SGS sites. However, floods also occurred frequently in winter, but the simulations generated few runoff events at that time of the year. These results have important implications for sustainability of grazed pastures and long-term simulation modelling of the hydrological balance of such systems, since runoff generation processes are likely to vary both spatially and temporally for different rainfall events.



1996 ◽  
Vol 18 (2) ◽  
pp. 270 ◽  
Author(s):  
J Landsberg ◽  
J Stol

The densities and distributions of sheep, kangaroos and feral goats were assessed from extensive dung surveys following dry, moderate and green seasons in three large paddocks in the wooded rangelands of north-westem New South Wales. Densities of sheep (21 9nanimals/km2) were around the long-term district average. Densities of goats (24 animals/km2) were often higher than sheep. Densities of kangaroos (1 1 animals/km2) were usually much lower than either sheep or goats. Animal density was usually related to vegetative cover (ground cover for sheep and kangaroos, shrub and tree cover for goats), but there were also differences among paddocks. Distribution of kangaroos showed the most differentiation according to vegetation type, with densities being consistently high on a small area of alluvial grassland and very low in the paddock with no alluvial plains and the lowest levels of ground cover. The distributions of sheep and goats were correlated in the dry season and both species showed similar ranges in preferences for different vegetation types. Of the large herbivores present in these woody rangelands, kangaroos were the most selective in terms of the vegetation types they grazed, and goats were the least selective. Because their grazing activities are focussed on alluvial grasslands, kangaroos have potential to degrade this locally uncommon vegetation type. However, the densities of kangaroos in other, more widespread, vegetation types were uniformly low. Goats were frequently the most abundant large herbivores present and were also the least selective. Therefore goats probably have the greatest potential for causing widespread grazing impacts across much of these woody rangelands.



2005 ◽  
Vol 45 (12) ◽  
pp. 1603 ◽  
Author(s):  
G. M. Lodge ◽  
L. H. McCormick ◽  
S. Harden

Hyparrhenia hirta (L.) Stapf (Coolatai grass) has invaded large areas of grazed native grasslands on the North-West Slopes of New South Wales (NSW) and is widespread along roadsides and travelling stock routes. It is commonly regarded as an invasive, weedy species with low forage value when it is tall and rank, but may be more palatable when kept short, green and leafy. A study (1990–2001) of a naturalised stand of Coolatai grass in the Manilla district of northern NSW examined its herbage mass (kg DM/ha), persistence (basal cover %), and grazing value under 2 contrasting grazing treatments: pastures that had either large amounts of dry, unpalatable herbage [light grazing at 5 dry sheep equivalents (DSE)/ha] or were short, green and leafy (strategic heavy grazing at a stocking rate of 37 DSE/ha). Effects of pre-grazing treatments (slashing, burning, and no defoliation) were also examined and data (litter mass, plant basal area, ground cover, and soil and litter microbial carbon and nitrogen) collected to assess the long term sustainability of these grazing systems. Sheep grazed the light grazing treatment for about 34% of the experimental period, with the strategic heavy grazing treatment being grazed for about 7% of the time. Over the experimental period this equated to 6752 DSE grazing days/ha for the light grazing treatment compared with 10 120 DSE for the heavy grazing treatment. Herbage mass in the heavy grazing treatment declined to <1000 kg DM/ha within 6 months of the start of grazing and remained below this level until December 1998 when stocking rates were switched (i.e. plots previously grazed at low stocking rate were subjected to the heavier rate and vice versa). In contrast, mean herbage mass in the light grazing treatment was generally >3000 kg DM/ha from November 1990–98, but a high proportion of this was dead standing material that carried over from season to season. Mean Coolatai grass basal cover was 9.5% in November 1990, increasing over time to about 25% in both grazing treatments by December 2000. Coolatai grass herbage accumulation was highly seasonal, ranging from as high as 70 kg DM/ha.day in summer to 0 in winter. In both grazing treatments, forage quality was low for both green and dead material, with mean crude protein being 6.0 (green) and 3.4% (dead). Digestible dry matter values ranged from 41 to 62% (green) and 32 to 51% (dead) and mean metabolisable energy values were 7 (green) and 5.3 MJ/kg DM (dead). After 8 years, the heavy grazing treatment had lower (P<0.05) litter mass, ground cover, plant basal area and soil microbial C and N levels than the light grazing treatment, but switching of the stocking rates restored most indicators, except the soil microbial values.



1968 ◽  
Vol 16 (1) ◽  
pp. 49 ◽  
Author(s):  
PD Dwyer

The biology of Miniopterus australis was investigated in north-eastern New South Wales (latitude c. 30�S) between 1960 and 1966. In this area the species reaches the southern limit of its distribution and is largely confined to the subtropical coastal belt. Mating occurs in the winter months June and July, and is followed by a period of retarded embryonic development to mid-September. Births occur in December. The only nursery colony of M. australis located was that of the southernmost population of the species. It included about 4000 individuals (approximately 1800 young) in December and was intimately associated with a much larger nursery colony of M. schreibersii. A comparison of the winter behaviour of M. australis with that of M. schreibersii at the same latitude revealed that pre-winter increase in weight is less marked, that feeding behaviour persists longer, and that there are fewer, and less rigid, periods of torpidity in the former species. In its reproductive and wintering characteristics M. australis, at 30�S., has diverged less from the tropical, and presumably ancestral, pattern for the genus than has M. schreibersii at the same latitude. It is argued that M. australis has colonized New South Wales from low latitudes later than M. schreibersii and that colonization southwards may have been dependent upon, or promoted by, the prior existence of M. schreibersii nursery colonies. An analysis of retrapping data for the southernmost population of M. australis suggests that this is represented as two subpopulations (highland and lowland) between which adult individuals seldom exchange. Spermatogenesis, and hence mating, occurs slightly earlier in the highland subpopulation. It is suggested that earlier mating in this subpopulation may be selectively advantageous, and that the long-term effect of selection here could be to shift the timing of reproductive events in the entire population back towards that observed in M. schreibersii. Earlier mating should be correlated with a stronger manifestation of pre-winter increase in weight and of winter torpidity. The combination of all these changes in M. australis would permit further range expansion to the south and west, provided that suitable nursery sites are available and can be found.



1981 ◽  
Vol 21 (111) ◽  
pp. 382 ◽  
Author(s):  
GM Lodge ◽  
BA Hamilton

A group of six-month-old Merino wether weaners was grazed from January to July 1977 on a natural pasture containing seeds of wiregrass (Aristida ramosa), corkscrew grass (Stipa variabilis), barley grass (Hordeum leporinum) and burrs of Medicago minima. The sheep were then removed from the natural pasture, shorn and grazed for a further 23 months on lucerne and oats pastures that were free of grass seed. The number and species of grass seeds and burrs in the wool, hide and carcases were measured to determine the levels of seed and burr contamination and the long-term fate of seeds entering the carcase. The highest number of seeds in the wool, hide and carcase of sheep grazing natural pasture were those of wiregrass. Numbers of seeds of this species per 100 cm2 ranged from 85 to 651 in the wool, 43 to 159 in the hide, and 1 to 8 in the carcase. Most of the grass seeds in the wool were located on the stomach and shoulders, while most of the burrs were on the hind legs and stomach. Percentages of grass seed were highest about the stomach area and shoulders for the hide and carcase, respectively. After the sheep were removed from the natural pasture, and grazed on lucerne and oats pastures for 23 months, the mean grass seed contents decreased by 81% in the hide and 83% in the carcase. Wiregrass seeds were the only seeds that penetrated the hide and remained in the carcase. Numbers of contaminating seeds decreased most rapidly within 6 months of the sheep being removed from the natural pasture. Over the experimental period no seed-free hides or carcases were observed.



1987 ◽  
Vol 27 (4) ◽  
pp. 533 ◽  
Author(s):  
SM Bromfield ◽  
RW Cumming ◽  
DJ David ◽  
CH Williams

Soil profiles from limed and unlimed commercial pastures and from lime trials on pastures in the Crookwell district of the Southern Tablelands of New South Wales were sampled and pH measured at 2- or 5-cm intervals to depths ranging from 10 to 60 cm. A single application of lime (3.6-5.6 t/ha depending on the soil) incorporated into the surface 10 cm had a long-term effect and maintained pH above 5.5 in the top 30 cm for at least 12 years. Lime applied as a topdressing to soils on granite raised the pH by at least 0.2 pH units to a depth of 15 cm after 6 years. The depth affected was less on the heavier-textured basaltic soils and on the initially more acid sedimentary soils. There appears to be a role for top-dressing with lime to prevent subsurface acidity from developing under pastures and to correct it in the upper layers of light textured soils. The pH profiles from a given treatment were variable and highlighted the problem of obtaining a field measurement for soil pH that is representative of the plant's environment.



2009 ◽  
Vol 49 (10) ◽  
pp. 837 ◽  
Author(s):  
J. M. Lilley ◽  
A. D. Moore

Inadequate ground cover because of over-grazing of pastures, fallowing and stubble burning or excessive cultivation exposes land to degradation, yet maintaining cover can constrain productivity. We used long-term simulation analysis to investigate the impact of modifying stock and crop management practices on the trade-off between farm productivity (grain, meat and wool) and ground cover levels. Management of mixed farms at five locations (426–657 mm mean annual rainfall) in the Murrumbidgee catchment of New South Wales was represented for simulated farms that included permanent pastures, crop–pasture rotations, and a meat/wool sheep enterprise. Locations varied in their stocking rate, soil characteristics and proportion of land area allocated to various crops and pastures. At each location we investigated the impact on ground cover and farm productivity of (1) retention of wheat stubble, (2) altering stocking rate (up to ±25%) and (3) moving stock elsewhere on the farm when the mean value of ground cover fell below a given threshold (50, 60, 70, 80 or 90%) for either, all pasture on the farm or an individual paddock. The analysis showed that seasonal conditions were the dominant effect on the mean farm cover (mean range 64–98%); cover fell as low as 43–57% in severe droughts, depending on location. Retention of wheat stubble increased long-term mean cover by 1–4%, with little impact on grain yield. Altering stocking rate had the largest impact on cover at all locations (up to 4%), although there was a trade-off with productivity. Maintaining a constant stocking rate, although moving stock within the farm, had a small, positive effect on the whole-farm cover, although it reduced gross margin because of the cost of supplementary feeding. Confining stock to a 3 ha feeding lot was the most effective strategy for maintaining ground cover and minimising financial loss. Our analysis did not account for the benefits of maintaining high levels of ground cover on the long-term productive capacity of the farm through on-farm or off-farm environmental benefits. We conclude that ground cover is dominated by climatic effects, and that within the range of stock management practices examined in the present study, practices that increase minimum cover levels also reduce farm productivity. Reducing total stocking rate, or removing stock from the farm during periods of low cover, will have the greatest impact on maintaining cover, although it will reduce whole-farm profit.



1975 ◽  
Vol 15 (77) ◽  
pp. 812 ◽  
Author(s):  
MH Campbell ◽  
KF Flemons ◽  
JJ Dellow

Methods for controlling St. John's wort (Hypericum perforatum var. angustifolium) on non-arable land were investigated in two experiments near Tuena, New South Wales. The effects of herbicides, seed, fertilizer and the timing of the application of these inputs on the establishment of surface-sown legumes and grasses, and on the control of St. John's wort were ascertained. The herbicides, amitrole, 2,4-D, 2,4-D + 2,4,5-T, and picloram were applied with and without 2,2-DPA (sodium 2,2-dichloropropionate) ; glyphosate (N-phosphonomethyl glycine) was applied alone. Establishment, survival and ground cover of sown species and the control of St. John's wort were recorded for up to two years after treatment. Herbicide application was essential for the establishment of cocksfoot (Dactylis glomerata) and phalaris (Phalaris tuberosa), but not for subterranean clover (Trifolium subterraneum), on land infested with St. John's wort. Establishment of grasses and legumes was achieved in one experiment by spraying in late summer and sowing in late autumn, and in another experiment by spraying in late autumn and sowing in early winter. Glyphosate was the most effective herbicide in controlling St. John's wort and associated weeds and in promoting the establishment and development of grasses and legumes. However, good establisment of improved species and good control of St. John's wort was also attained on the 2,4-D and 2,4-D f 2,4,5-T treatments. Thus, until glyphosate becomes commercially available, the most economical method for control of St. John's wort on non-arable land will be the aerial application of 2,4-D + 2,2-DPA three weeks after a distinct autumn break followed by seed and fertilizer three weeks later.



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