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1
Harries, Martin, Ken C. Flower, Craig A. Scanlan, Michael T. Rose e Michael Renton. "Interactions between crop sequences, weed populations and herbicide use in Western Australian broadacre farms: findings of a six-year survey". Crop and Pasture Science 71, n. 5 (2020): 491. http://dx.doi.org/10.1071/cp19509.
Testo completoAbstract (sommario):
Six years of survey data taken from 184 paddocks spanning 14 million ha of land used for crop and pasture production in south-west Western Australia were used to assess weed populations, herbicide resistance, integrated weed management (IWM) actions and herbicide use patterns in a dryland agricultural system. Key findings were that weed density within crops was low, with 72% of cropping paddocks containing fewer than 10 grass weeds/m2 at anthesis. Weed density and herbicide resistance were not correlated, despite the most abundant grass weed species (annual ryegrass, Lolium rigidum Gaudin) testing positive for resistance to at least one herbicide chemistry in 92% of monitored paddocks. A wide range of herbicides were used (369 unique combinations) suggesting that the diversity of herbicide modes of action may be beneficial for reducing further development of herbicide resistance. However, there was a heavy reliance on glyphosate, the most commonly applied active ingredient. Of concern, in respect to the evolution of glyphosate resistant weeds, was that 45% of glyphosate applications to canola were applied as a single active ingredient and area sown to canola in Western Australia expanded from 0.4 to 1.4 million hectares from 2005 to 2015. In order to minimise the weed seed bank within crops, pastures were used infrequently in some regions and in 50% of cases pastures were actively managed to reduce weed seed set, by applying a non-selective herbicide in spring. The use of non-selective herbicides in this manner also kills pasture plants, consequently self-regenerating pastures were sparse and contained few legumes where cropping intensity was high. Overall, the study indicated that land use selection and utilisation of associated weed management actions were being used successfully to control weeds within the survey area. However, to successfully manage herbicide resistant weeds land use has become less diverse, with pastures utilised less and crops with efficacious weed control options utilised more. Further consideration needs to be given to the impacts of these changes in land use on other production factors, such as soil nutrient status and plant pathogens to assess sustainability of these weed management practices in a wider context.
2
James, T. K., e A. Rahman. "Management and control options for tutsan (Hypericum androsaemum) in hill country pastures a review". New Zealand Plant Protection 68 (8 gennaio 2015): 124–31. http://dx.doi.org/10.30843/nzpp.2015.68.5880.
Testo completoAbstract (sommario):
Tutsan (Hypericum androsaemum) is a highly invasive semievergreen shrubby weed found throughout New Zealand Described as a serious pasture weed in 1937 it has been held in check for many years by tutsan rust Recently it has spread rapidly into pasture forestry and conservation areas Present methods available for managing tutsan are proving inadequate and unsustainable This review paper provides an overview of tutsans biology ecology habitat and its current distribution in New Zealand It details possible management strategies and control options with emphasis on control by herbicides The paper identifies a number of potential herbicides which although not currently registered for control of tutsan have shown good efficacy on this weed and could be developed for use on agricultural land through further research Herbicides currently registered for control of tutsan in Australia as well as the current recommendations in Victoria and Western Australia are also summarised
3
Powles, Stephen B., e Peter D. Howat. "Herbicide-resistant Weeds in Australia". Weed Technology 4, n. 1 (marzo 1990): 178–85. http://dx.doi.org/10.1017/s0890037x00025203.
Testo completoAbstract (sommario):
This review considers the development of herbicide-resistant weed biotypes in Australia. Biotypes of the important annual weed species, capeweed, wall barley, and hare barley are resistant to the bipyridylium herbicides paraquat and diquat. These resistant biotypes developed on a small number of alfalfa fields that have a long history of paraquat and diquat use within a distinct geographical area in central western Victoria. The resistant biotypes are controlled by alternative herbicides and pose little practical concern. Some populations of wild oat are resistant to the methyl ester of diclofop. Of greatest concern is the development of cross resistance in biotypes of rigid ryegrass to aryloxyphenoxypropionate, cyclohexanedione, sulfonylurea, and dinitroaniline herbicides. The cross-resistant rigid ryegrass infests crops and pastures at widely divergent locales throughout the cropping zones of southern Australia. The options for control of cross-resistant rigid ryegrass by herbicides are limited. A biotype of rigid ryegrass on railway tracks treated for 10 yr with amitrole plus atrazine has resistance to amitrole and atrazine and other triazine, triazinone, and phenylurea herbicides. Management tactics for cross resistance are discussed.
4
Semple, WS, TB Koen e IA Cole. "Establishing Native Grasses in Degraded Pastures of Central Western New South Wales." Rangeland Journal 21, n. 2 (1999): 153. http://dx.doi.org/10.1071/rj9990153.
Testo completoAbstract (sommario):
Renewed interest in native grasses in recent years has led to the release of a small number of cultivars but for most native species, seed is only available from wild stands. Seed can be harvested with a brush harvester but cleaning seed to a level that will allow it to pass through conventional sowing equipment is often difficult. Techniques for successful field establishment of native species are still not fully understood. From 1993 to 1995, native grasses (mainly warm-season types) were sown in early spring in exotic pastures at a number of sites in the Central West of NSW. Various seedbed types, sowing methods and species were evaluated in six experiments. In five of the experiments, establishment was low for most species - a result attributed primarily to weed competition. At one site in 1994, however, the combination of a cultivated seedbed, 18 months of pre-sowing weed control, relatively low soil fertility and a high sowing rate resulted in high emergence of most species and acceptable survival of Paspalidium jubi$orum, Themeda australis and to a lesser extent, Chloris ventricosa and C. truncata. Key words: exotic species, native species, emergence, survival, seedbed, weed control.
5
Tozer, K. N., D. F. Chapman, P. E. Quigley, P. M. Dowling, R. D. Cousens e G. A. Kearney. "Effect of grazing strategy, ryegrass overdrilling and herbicide application on vulpia content, tiller density and seed production in perennial pastures". Australian Journal of Experimental Agriculture 48, n. 5 (2008): 632. http://dx.doi.org/10.1071/ea06144.
Testo completoAbstract (sommario):
Vulpia species C.C. Gmel. are annual grass weeds that can reduce the productivity of perennial pastures throughout southern Australia. To develop more effective strategies to manage vulpia, a 3-year experiment was established in western Victoria (average annual rainfall: 625 mm) comparing different methods currently used to control this weed. Overdrilling perennial ryegrass (Lolium perenne L.) seed and simazine application treatments were applied to phalaris (Phalaris aquatica L.) pastures that were set-stocked or rotationally grazed (either as a four-paddock or strategic rotation) with Merino ewes. The content of vulpia, subterranean clover (Trifolium subterraneum L.) and other annual grasses as a proportion of total dry matter increased, and the proportion of phalaris decreased in most grazing treatments throughout the experiment. The mean vulpia content was lowest and the phalaris content was highest in the four-paddock rotation, whereas vulpia content was greatest and phalaris content was lowest under set-stocking. Simazine application in June with or without ryegrass overdrilling reduced the number of vulpia tillers/m2 in 2000 and 2001 and vulpia panicle production in 2000, although vulpia populations increased to pretreatment levels in herbicide-treated swards by 2002. The number of vulpia seeds in the soil seed bank was not affected by any of the treatments. The most effective treatment was a combination of ryegrass overdrilling and herbicide application in the four-paddock, rotationally grazed pastures. This experiment highlights the need for an integrated approach to manage vulpia since relying on herbicide application alone is ineffective. This is particularly the case when competitive pasture species are unable to adequately utilise available resources and prevent a recovery in vulpia populations.
6
Tozer, K. N., D. F. Chapman, P. E. Quigley, P. M. Dowling, R. D. Cousens e G. A. Kearney. "Integrated management of vulpia in dryland perennial pastures of southern Australia". Crop and Pasture Science 60, n. 1 (2009): 32. http://dx.doi.org/10.1071/cp07445.
Testo completoAbstract (sommario):
Vulpia (Vulpia species C.C. Gmel.) are annual grass weeds that can reduce pasture quality and stock-carrying capacity of perennial pastures throughout southern Australia. To develop more effective strategies to control vulpia, an experiment was established in western Victoria (average annual rainfall 565 mm) in phalaris (Phalaris aquatica L.) pastures comparing the effects of control methods [comprising combinations of fertiliser addition (Fert), a single herbicide (simazine) application (Sim), and pasture rest from grazing (Rest)] on vulpia populations. A further herbicide treatment [paraquat-diquat (SpraySeed®)] was imposed on some of these treatments. Measurements included botanical composition, phalaris and vulpia tiller density, seed production, and number of residual seeds in the soil. Vulpia content remained unchanged in the Sim-Rest treatment but increased in all other management treatments over the duration of the 3 year study and especially where paraquat-diquat was applied, despite paraquat-diquat causing an initial reduction in vulpia content. Vulpia content was lowest in the Fert-Sim-Rest treatment. The Fert-Sim treatment and in some cases paraquat-diquat application reduced vulpia tiller production. Vulpia seed production and the residual seed population were not influenced by any of the management treatments, while the single paraquat-diquat application increased vulpia seed production 18 months after application. Phalaris content was enhanced by the Sim-Rest and Fert-Sim-Rest treatments and initially by paraquat-diquat. No treatment affected phalaris tiller production and basal cover. The subterranean clover (Trifolium subterraneum L.) content declined during the experiment, but to a lesser extent where paraquat-diquat was applied. Volunteer species content was initially suppressed in the year following paraquat-application, although populations recovered after this time. Of the two Vulpia spp. present (V. bromoides (L.) S.F. Gray and V. myuros (L.) C.C. Gmelin), V. bromoides was the most prevalent. Results show how a double herbicide application can increase vulpia fecundity and rate of re-infestation of herbicide-treated sites. Pasture rest shows some promise, but to a lesser extent than in the New South Wales tablelands, where summer rainfall may increase the growth of perennial species. In lower rainfall, summer dry areas, responses to pasture rest may be slower. Despite this, integrated management (which combines strategies such as pasture rest, herbicide application, and fertiliser application) increases the perennial content and reduces vulpia seed production, thus improving vulpia control.
7
Monjardino, M., D. J. Pannell e S. B. Powles. "The economic value of pasture phases in the integrated management of annual ryegrass and wild radish in a Western Australian farming system". Australian Journal of Experimental Agriculture 44, n. 3 (2004): 265. http://dx.doi.org/10.1071/ea03050.
Testo completoAbstract (sommario):
Most cropping farms in Western Australia must deal with the management of herbicide-resistant populations of weeds such as annual ryegrass (Lolium rigidum Gaudin) and wild radish (Raphanus raphanistrum�L.). Farmers are approaching the problem of herbicide resistance by adopting integrated weed management systems, which allow weed control with a range of different techniques. One important question in the design of such systems is whether and when the benefits of including pasture in rotation with crops exceed the costs. In this paper, the multi-species resistance and integrated management model was used to investigate the value of including pasture phases in the crop rotation. The most promising of the systems examined appears to be so-called 'phase farming', involving occasional 3-year phases of pasture rather than shorter, more frequent and regular pasture phases. This approach was competitive with the best continuous cropping rotation in a number of scenarios, particularly where herbicide resistance was at high levels.
8
Turner, Neil C., e Senthold Asseng. "Productivity, sustainability, and rainfall-use efficiency in Australian rainfed Mediterranean agricultural systems". Australian Journal of Agricultural Research 56, n. 11 (2005): 1123. http://dx.doi.org/10.1071/ar05076.
Testo completoAbstract (sommario):
Mediterranean environments are characterised by hot, dry summers and cool, wet winters. The native vegetation in Mediterranean-climatic regions is predominantly perennial shrubs and trees intermixed with annual forbs. In south-western Australia, the spread of agriculture has seen the well adapted perennial vegetation replaced by rainfed annual crops and pastures. This has increased waterlogging and secondary salinity, thereby causing loss of productivity in ~10% of the cleared land area. To reduce deep drainage and make the agricultural systems environmentally sustainable requires the re-introduction of perennial vegetation in the form of belts of trees or shrubs, and phase-farming systems with perennials such as lucerne replacing annual pastures between the cropping years. To be economically viable, agricultural productivity needs to increase by at least 3% per annum. Yields of dryland wheat, the predominant crop in the Mediterranean agricultural regions of Australia, have increased at ~1%/year for the century preceding the 1980s and since then by nearly 4%/year. Increases have arisen from both genotypic and agronomic improvements. Genotypic increases have arisen from selection for earliness, early vigour, deep roots, osmotic adjustment, increased transpiration efficiency, improved disease resistance, and an improved harvest index from high ear weight (grain number) at flowering and high assimilate storage and remobilisation. Agronomic increases have arisen from early sowing that has been enabled by minimum tillage, increased fertiliser use, especially nitrogen, weed control, and rotations to improve weed control, minimise disease risk, and increase nitrogen availability. Evidence is presented suggesting that the rapid increase in yield of wheat in the last two decades has likely arisen from the rapid adoption of new technologies. For productivity to be maintained in the face of the increasing requirement to be environmentally sustainable will be a challenge and will require better integration of breeding and agronomy.
9
McKenzie, John, Dannielle Brazier, Shane Campbell, Joseph Vitelli, Angela Anderson e Robert Mayer. "Foliar herbicide control of sticky florestina (Florestina tripteris DC.)". Rangeland Journal 36, n. 3 (2014): 259. http://dx.doi.org/10.1071/rj13091.
Testo completoAbstract (sommario):
Sticky florestina (Florestina tripteris DC.) is an annual exotic weed that has become naturalised near the townships of Tambo and Barcaldine in central western Queensland, Australia. Three experiments conducted near Barcaldine identified foliar herbicides effective in killing sticky florestina plants and in providing residual activity to reduce recruitment from the soil seed bank. An initial chemical screening experiment evaluated the efficacy of 28 herbicide treatments. The most promising herbicides were then further evaluated in two response-rate experiments. Overall, 2,4-D/picloram, aminopyralid/fluroxypyr, clopyralid, metsulfuron-methyl and triclopyr/picloram proved to be the most effective selective herbicides. Two of these, metsulfuron-methyl at 18 g active ingredient (a.i) ha–1 and 2,4-D + picloram at 900 g a.i. ha–1 + 225 g a.i. ha–1 have now been included in a minor use permit (PER11920) with the Australian Pesticides and Veterinary Medicines Authority (APVMA) for the control of sticky florestina in pasture, stock route, roadside and non-crop situations using both spot and boom-spray applications (APVMA 2010). The permit also allows the use of 2,4-D amine for the control of seedlings only.
10
Anderson, W. K., G. B. Crosbie e W. J. Lambe. "Production practices in Western Australia for wheats suitable for white, salted noodles". Australian Journal of Agricultural Research 48, n. 1 (1997): 49. http://dx.doi.org/10.1071/a95133.
Testo completoAbstract (sommario):
Wheat cultivars acceptable for the Noodle wheat segregation in Western Australia were compared with cultivars suitable for the Australian Standard White (ASW) grade over the period 1989–93. Yield and grain quality responses to sowing time, nitrogen fertiliser, soil type, and cropping history were examined to determine management practices most likely to result in wheat grain suitable for the production of white, salted noodles. Thirty experiments were conducted in the 300–450 mm average annual rainfall zone between Three Springs in the north (approx. 29° 30′S) and Newdegate in the south (approx. 33°10′S). The ASW cultivars, Spear, Kulin, and Reeves, outyielded the Noodle cultivars, Gamenya and Eradu, by 8–10% on average, but the yield difference was less at later sowings. The optimum sowing time was early May for most cultivars. The new cultivars, Cadoux (Noodle) and Tammin (potential Noodle, but classiffied General Purpose), tested in 1992 and 1993 in 12 experiments showed an optimum sowing time of late May, as did other midseason cultivars. Grain yields of May-sown crops were increased by 13 kg for every 1 kg of nitrogen applied, compared with 3 : 1 for June-sown crops. Previous legume history of the site and grass weed control in the crop also influenced the grain protein percentage. It was concluded that adoption of production guidelines that include sowing at, or near, the break of the season with about 40 kg/ha of nitrogen fertiliser, a rotation that includes 2-3 years of legume crop or pasture in the previous 5 years, and adequate grass weed control will result in an excellent chance (>80%) of producing grain proteins within the receival standards for the Noodle grade. Flour swelling volume (FSV), an indicator of noodle eating quality, was negatively correlated (not always significantly at P = 0·05) with grain protein percentage in 7 out of 8 experiments. FSV values were larger from sites located in the south of the study area and this appeared to be independent of protein and time-of-sowing effects. Small grain sievings (<2 mm) were increased by sowing after the end of May, especially in the longer season cultivars.
11
Peirce, JR. "Morphological and phenological variation in three populations of saffron thistle (Carthamus lanatus L.) from Western Australia". Australian Journal of Agricultural Research 41, n. 6 (1990): 1193. http://dx.doi.org/10.1071/ar9901193.
Testo completoAbstract (sommario):
Saffron thistle (Carthamus lanatus L.), an erect spiny annual herb, is a weed of pasture and cereal crops in some agricultural areas of southern Australia. Cypselas (achenes or seeds) were collected from mature plants at three sites near Salmon Gums, Moorine Rock and Greenough in Western Australia and grown at South Perth. Two forms were observed and could be distinguished by differences in their phenology and the shape of cotyledons and achenes. After two generations at South Perth, germination in the presence or absence of leaching with water or after storage at daily fluctuating temperatures of 15-60�C indicated that there were differences between forms as well as between different accessions of the same form. This result suggests that genetic as well as environmental factors influence the breakdown of dormancy and promote germination. Differences in germination were detected when a single accession was sown at two sites, one in the south and the other in the north of the cereal-growing region of Western Australia. Low rainfall and temperatures in autumn were primarily responsible for slow and staggered germination at the more southern site. The protracted germination of saffron thistle in the southern cereal-growing districts creates a problem for cultural control and correct timing of herbicide applications.
12
Pearce, K. L., D. G. Masters, G. M. Smith, R. H. Jacob e D. W. Pethick. "Plasma and tissue α-tocopherol concentrations and meat colour stability in sheep grazing saltbush (Atriplex spp.)". Australian Journal of Agricultural Research 56, n. 7 (2005): 663. http://dx.doi.org/10.1071/ar05001.
Testo completoAbstract (sommario):
Dry senesced pastures available during the summer and autumn period in Western Australia and other areas with a Mediterranean climate are low in vitamin E. The use of expensive and labour-intensive supplements to prevent nutritional myopathy induced by vitamin E deficiency in weaner sheep is common. Low vitamin E concentrations in the muscle preslaughter can also reduce the shelf life of meat. There is growing interest in incorporating saltbush into farming systems in Western Australia. The potential for saltbush to boost the vitamin E status of sheep and improve the shelf life of meat was investigated. Fifty (2 × 25) 18-month-old Merino hogget wethers (average liveweight 48 kg) were grazed on either a saltbush-dominant saline pasture or on a ‘control’ dry pasture, stubble plot for 14 weeks. At the start of the experiment, all animals were orally supplemented with 2500 IU of dl-α-tocopherol acetate in 6.25 mL solution. The α-tocopherol content in saltbush was 139 and 116 mg/kg dry matter for old man and river saltbush, respectively. Concentrations of α-tocopherol were measured in plasma at Weeks 0, 4, 8, and 12 and in muscle and liver samples taken at slaughter. Grazing on saltbush significantly elevated α-tocopherol concentrations in the liver and muscle compared with grazing on dry pasture, well above the threshold for vitamin E inadequacy (P < 0.001). Plasma α-tocopherol concentrations in sheep fed saltbush increased up to Week 8 and then decreased until the end of the experiment as availability of saltbush declined (P < 0.05). Plasma α-tocopherol in sheep fed dry pasture increased in the first 4 weeks due to the initial vitamin E treatment but declined thereafter, indicating that the pasture was low in vitamin E. The high muscle concentrations of α-tocopherol in sheep fed saltbush also improved colour stability and may have had an influence on drip and cooking loss. The meat from the saltbush-grazed sheep was moister but drip and cooking loss was the same as from the drier meat of the control sheep. In conclusion, this study demonstrates that saltbush is a potential vitamin E source for sheep.
13
Borger, C. P. D., G. P. Riethmuller e A. Hashem. "Emergence, survival, biomass production, and seed production of Chloris truncata (windmill grass) in the Western Australian wheatbelt". Crop and Pasture Science 62, n. 8 (2011): 678. http://dx.doi.org/10.1071/cp11018.
Testo completoAbstract (sommario):
Chloris truncata is a C4 grass species, native to Australia. Within the wheatbelt of Western Australia (WA), it is a weed of grain cropping systems and a beneficial forage species within pasture systems. Plant emergence, density, survival, biomass production, seed production, and seed germinability were investigated, in pasture or cropping systems, at two trial sites (in Merredin, WA) over two years (from 2007 to 2009). Chloris truncata predominantly emerged and set seed during spring and early summer. This species is usually referred to as a short-lived perennial, and could survive for >14 months, but predominantly grew as a spring/summer annual in the WA wheatbelt. Maximum plant density, biomass, and seed production were, respectively, 4.2–28.2 plants/m2, 8.3–146.1 g dry biomass/m2, and 3325–61 383 seeds/m2, depending on location. Cohorts emerging in spring produced more seeds than those that emerged during other seasons. Average seed germinability reached a maximum of 62%, following an initial 3–4-month period of dormancy. There are few herbicides to control plants growing within the winter/spring annual grain crops, and so further research into increased crop competitive ability is required to reduce growth of spring cohorts and potentially reduce seed set. However, the biomass produced by C. truncata (range 0–1460 kg/ha) can be used as forage in a pasture system, or over the summer/autumn feed gap in a cropping system.
14
Hurst, Thomas, e Paul I. Boon. "Agricultural weeds and coastal saltmarsh in south-eastern Australia: an insurmountable problem?" Australian Journal of Botany 64, n. 4 (2016): 308. http://dx.doi.org/10.1071/bt16027.
Testo completoAbstract (sommario):
It is often assumed that saline coastal wetlands experience environmental conditions so severe that they are largely immune to invasion by exotic plant species. The belief is implicit in many older reviews of threats to mangroves and coastal saltmarshes, where a limited range of vascular plant taxa, often focussing on *Spartina, (throughout the paper an asterisk denotes an introduced (exotic) species as per Carr 2012) have been invoked as the major species of concern. Even though the weed flora of southern Australia is derived largely from agriculture and horticulture, neither of which includes many species tolerant of waterlogged, variably saline environments, a recent assessment of Victorian saline coastal wetlands indicated that exotic plants were the third-most pervasive threat, after land ‘reclamation’ and grazing. Tall wheat grass, *Lophopyrum ponticum (Podp.) A.Love., is one of the most severe and widely distributed weeds of saline coastal wetlands in south-eastern Australia. It is promoted by the agricultural extension arm of the Victorian government as a salt-tolerant pasture grass; however, its broad ecological amplitude and robust life form make it a most serious invader of upper saltmarsh in Victoria. We assessed the effectiveness of different control measures, including slashing and herbicides, for the management of *L. ponticum infestations (and their side effects on saltmarsh communities) in the Western Port region of Victoria. A nominally monocot-specific herbicide widely used to control *Spartina, Fluazifop-P, was ineffective in controlling *L. ponticum. The broad-spectrum systemic herbicide glyphosate was more effective in controlling *L. ponticum, but had undesirable impacts on native plant species. Controlling weeds in coastal wetlands using available herbicides for use near coastal waterways would seem to remain problematic.
15
Mitchell, GJ, RJ Carter e SR Chinner. "Studies on the control of water-dropwort (Oenanthe pimpinelloides) in South Australia". Australian Journal of Experimental Agriculture 35, n. 4 (1995): 483. http://dx.doi.org/10.1071/ea9950483.
Testo completoAbstract (sommario):
Water-dropwort (Oenanthe pimpinelloides L.), a tuberous perennial herb, is currently known in South Australia from only a single locality in the Mount Lofty Ranges. There is little information on water-dropwort control, and 2 experiments were conducted to assess the effects of sowing pasture, with or without presowing herbicides, on the control of this weed. Phalaris (Phalaris aquatica L.) and perennial clovers were successfully introduced into infested pastures by direct drilling in autumn. Water-dropwort regenerated from seed more densely in unsown plots than plots of established perennial pasture, suggesting that upgrading pastures may be a strategy to reduce the rate of spread by seed of this weed. A range of herbicide treatments applied to waterdropwort at the stem elongation stage in spring before autumn sowing of pastures provided effective shortterm control. The best short-term control was provided by glyphosate at 1440 g a.i./ha; metsulfuron methyl at 6, 12, and 36 g a.i./ha; and metsulfuron methyl at 12 g a.i./ha tank-mixed with glyphosate or 2,4-D amine at 720 or 1000 g a.i./ha, respectively. These treatments, and chlorsulfuron at 21 g a.i./ha, also significantly (P<0.05) reduced water-dropwort abundance (relative to untreated areas) for up to 18 months after sowing and initially improved the density of sown pasture species, but these improvements were not evident 14 months after resowing. Although prior season herbicide treatments controlled water-dropwort in newly sown pastures, 2 separate applications of herbicides, in May and October, gave no better control of water-dropwort than a single herbicide application in spring. Water-dropwort infestations do not appear to prevent successful direct drilling of phalaris and perennial clovers. Although pasture renovation did not provide long-term suppression of water-dropwort, the maintenance of vigorous pastures may reduce the rate of population growth from seedlings of this weed. Recropping restrictions may limit the role of chlorsulfuron for water-dropwort control in pasture renovation situations.
16
Lattimore, MAE. "Pastures in temperate rice rotations of south-eastern Australia". Australian Journal of Experimental Agriculture 34, n. 7 (1994): 959. http://dx.doi.org/10.1071/ea9940959.
Testo completoAbstract (sommario):
Legume-based pastures have long been an integral part of rice growing in the southern New South Wales irrigation areas and still offer potential to improve the productivity, profitability, and sustainability of the temperate rice-cropping system.This paper reviews both historical and current aspects of pastures in temperate rice rotations in southern New South Wales and highlights the importance of pastures in sustaining this cropping system as environmental pressures increase. Topics discussed include pasture species and rotations, their role in improving soil fertility and sustainability, the value of pastures in weed control, and their management for maximum profitability.
17
Vere, David T., Bruce A. Auld e Malcolm H. Campbell. "Economic Assessments of Serrated Tussock (Nassella trichotoma) as a Pasture Weed". Weed Technology 7, n. 3 (settembre 1993): 776–82. http://dx.doi.org/10.1017/s0890037x00037702.
Testo completoAbstract (sommario):
Weeds reduce the livestock production from pastures and impose control costs on producers and governments. Economic assessments of pasture weed problems are required on and beyond the farm for planning private and public weed control. This requirement has several dimensions that can be used to demonstrate the economic effect of weeds and encourage weed control by the private and public sectors. This paper discusses the economic problems of pasture weeds and the procedures for multi-level economic assessments with a major pasture weed in Australia as an example, and demonstrates the important private and social economic benefits from controlling this weed.
18
Batson, M. G. "Agrostis castellana (Poaceae), Dominant Agrostis Species, Found in Bent Grass Pastures in South-eastern Australia". Australian Journal of Botany 46, n. 6 (1998): 697. http://dx.doi.org/10.1071/bt97065.
Testo completoAbstract (sommario):
There is considerable uncertainty that the traditional identification of bent grasses in south-eastern Australia as Agrostis capillaris L. (Syn. Agrostis tenuis Sibth.) is correct, due to a history of confusing nomenclature and mis-identification. Bent grass is considered a weed of pastures in the high-rainfall zone of south-eastern Australia and thus the correct identity of bent grass may have implications for its management and control. Populations of bent grass were sampled from 42 pastures in south-eastern Australia and Agrostis castellana Boiss. et Reuter, rather than A. capillaris, was found to be the dominant species of Agrostis in 33 out of 42 bent grass pastures sampled. Five of the nine pastures sampled in Tasmania contained A. capillaris as opposed to only 1 of the 33 pastures sampled in Victoria. Agrostis castellana had not been identified in Victoria or Tasmania prior to this work. Since A. castellana grows more vigorously by rhizomes than A. capillaris, control measures recommended for A. capillaris may not be relevant for bent grass pastures in south-eastern Australia. Ligule length, ligule width and width of lamina, measured to determine whether species of bent grass could be easily distinguished in the field, did not distinguish adequately between A. castellana and A. capillaris.
19
Borger, Catherine, Abul Hashem e Mario D’Antuono. "Summer weed species incidence in Western Australia varies between seasons". Weed Science 67, n. 05 (12 luglio 2019): 589–94. http://dx.doi.org/10.1017/wsc.2019.30.
Testo completoAbstract (sommario):
AbstractAgronomic surveys of summer weed species are necessary to identify future research directions for optimal weed control, but usually focus on agricultural fields in a single season. To survey all species in the absence of weed control measures and determine species variability between seasons, a survey of 133 sites was conducted on roadsides adjoining agricultural fields throughout the Western Australian grainbelt in early 2015 and repeated in 2016 and 2017. The survey identified 144 species, but only 19 species were evident at more than 10% of sites. The most common species were weeping lovegrass [Eragrostis curvula (Schrad.) Nees], fleabane (Erigeron sp.), windmillgrass (Chloris truncata R. Br.), and wild radish (Raphanus raphanistrum L). The survey highlighted that weed species incidence varied between years. For example, C. truncata incidence was 30% in 2015 and 55% in 2016, while stinkgrass [Eragrostis cilianensis (All.) Vignolo ex Janch.] ranged from 20% in 2015 to 50% of sites in 2017. Conversely, density of individual species on the roadside was usually low, and density remained consistent between years. The survey highlighted multiple weed species that will require further research to optimize management programs. Raphanus raphanistrum and wild oat (Avena fatua L.) in particular are an issue for growers, as these species are highly detrimental winter weeds, and the survey demonstrates that they can also be common summer weeds. Control of these species with nonselective herbicides in summer as well as winter is likely to exacerbate the development of herbicide resistance.
20
Campbell, MH. "Extending the frontiers of aerially sown pastures in temperate Australia: a review". Australian Journal of Experimental Agriculture 32, n. 1 (1992): 137. http://dx.doi.org/10.1071/ea9920137.
Testo completoAbstract (sommario):
Over the past 40 years large areas of pastures on hill country in temperate Australia have been improved through aerial distribution of herbicides, pesticides, seed, and fertiliser, which has increased animal production and helped to control weeds. Refinements detailed in this review could extend the use of these techniques to promote sustainable systems by the establishment of perennial pasture species on unploughed land. It is argued that the most urgent requirement is ensuring that aerial spraying is not abolished by government regulation in response to demands by specialist groups, because perennial pasture species will not establish on hill country without prior aerial spraying of herbicides. The major technical refinement needed is the reduction of losses of establishing plants due to weed competition and dry periods during their first spring and summer. This could be accomplished by increasing the spectrum of weeds controlled by the most widely used herbicide, glyphosate; applying new herbicides that give longer weed control in spring than the presently used herbicides; using herbicides that can selectively remove annual grass weeds from establishing perennial grasses; or using strategic grazing with cattle or goats to reduce weed competition. Breeding, selecting or importing pasture species specifically designed for establishment from surface sowing has never been attempted. Attributes that could improve establishment include germination that occurs only under favourable conditions; seeds resistant to weathering on the soil surface; seedlings with fast radicle entry, hairs on the radicle, fast root development, and better seedling vigour; and for subtropical species sown in semi-arid New South Wales, tolerance of low winter temperatures. Improved distribution of herbicides, seeds and fertilisers, particularly in the more rugged hill country, is needed to ensure complete cover of the treated area with minimum drift. Techniques that allow establishment of aerially sown pastures on hill country with very acid soil are needed to facilitate the development of further, large areas of Australia.
21
Bowman, A. M., Y. Alemseged, G. J. Melville, W. J. Smith e F. Syrch. "Increasing the perennial grass component of native pastures through grazing management in the 400 - 600mm rainfall zone of central western NSW". Rangeland Journal 31, n. 4 (2009): 369. http://dx.doi.org/10.1071/rj08032.
Testo completoAbstract (sommario):
Native grass-based pastures in the 400–600 mm rainfall zone of central NSW are an important basis for extensive grazing industries. However, over time they have been invaded by exotic weeds. This study aimed to evaluate several grazing strategies for the maintenance or improvement of native grasslands based on pasture productivity and species diversity. Seven grazing strategies, ranging from set stocking to permanently removing stock, were employed to evaluate the strategy that would best maintain a high proportion of desirable perennial grass species. Grazing treatments were evaluated based on their effects on pasture composition and on the density of selected key grass species such as Enteropogon acicularis (Lindl.) Lazar. (curly windmill grass). Managing the utilisation of the key desirable species E. acicularis combined with weed control was the most successful strategy in terms of increasing the density of the key species, although no treatment increased the proportion of desirable perennial grasses and desirable broadleaf species. This was followed by a ‘farmer’s choice’ strategy, which involved combining phosphorus fertiliser application, weed control and rest from grazing. In contrast, strategies that involved either a ‘summer lockup’ or ‘weed control’ alone performed poorly. It is concluded that native pastures in this region could be rehabilitated, and their productivity restored, by following strategies that provide rest from grazing, based on the utilisation levels of key, species combined with control of annual weeds.
22
Latta, R. A., e A. Lyons. "The performance of lucerne - wheat rotations on Western Australian duplex soils". Australian Journal of Agricultural Research 57, n. 3 (2006): 335. http://dx.doi.org/10.1071/ar04016.
Testo completoAbstract (sommario):
In field experiments on duplex soils in the south-eastern and central Western Australian wheatbelt, lucerne (Medicago sativa L.) was compared with subterranean clover (Trifolium subterraneum L.) in pasture–crop rotations. Comparative pasture plant densities and biomass, soil water content, available soil nitrogen, wheat grain yield, and protein content were measured during 2 and 3 years of pasture followed by 2 and 1 year of wheat, respectively. Lucerne densities declined by 60–90% over the 3-year pasture phase but produced up to 3 times more total annual biomass than weed-dominant annual pastures and similar total annual biomass when annual pastures were legume dominant. Lower soil water contents were measured under lucerne than under annual pastures from 6 months after establishment, with deficits up to 60 mm in the 0–1.6 m soil profile. However, significant rain events and volunteer perennial weeds periodically negated comparative deficits. Wheat yields were lower following lucerne (1.3 t/ha) than following an annual pasture (1.8 t/ha) in a low-rainfall season, higher (3.7 v. 2.9 t/ha) in a high-rainfall season, and much higher when the previous annual pastures were grass dominant (3.4 v. 1.5 t/ha). Grain protein contents were 1–2% higher in response to the lucerne pasture phase. Overcropping wheat into a lucerne pasture of 19 plants/m2 reduced wheat grain yields, but a lucerne density of 4 plants/m2 reduced yields only where rainfall was low. The study has shown that lucerne–wheat rotations provide a productive farming system option on duplex, sodic soils in both the south-eastern and central cropping regions of Western Australia. This was most evident in seasons of above-average summer and growing-season rainfall and when compared with grass-dominant annual pastures.
23
Warwick, S. I., e A. Francis. "The Biology of Invasive Alien Plants in Canada. 6. Berteroa incana (L.) DC". Canadian Journal of Plant Science 86, n. 4 (10 ottobre 2006): 1297–309. http://dx.doi.org/10.4141/p06-030.
Testo completoAbstract (sommario):
The cruciferous weed Berteroa incana, hoary alyssum, has been known in temperate North America since the late 19th century, but has recently begun to spread aggressively in upland and dry areas in the Great Lakes and western foothills regions of both Canada and the United States. It is an annual, winter annual to short-lived perennial and is considered an invasive weed in turf, rangelands, pastures and forage crops, with harmful effects on horses an added concern. The species is most common on sandy gravel and poorer soils. It has recently i nvaded Christmas tree plantations in Michigan. Its prolific seed production, woody stems and deep taproot enable it to persist under dry conditions and to resist mechanical control; and it has virtually no natural enemies in North America. It can be partially controlled by herbicides in crops it has invaded, but herbicides are not generally used on rangelands, pastures, turf and natural and semi-natural areas, where it is now prevalent. Key words: Berteroa incana, hoary alyssum, bertéroa blanc, BEFIN, weed biology, invasive alien
24
Anderson, GW, e RW Moore. "Productivity in the first seven years of a Pinus radiata-annual pasture agroforest in Western Australia". Australian Journal of Experimental Agriculture 27, n. 2 (1987): 231. http://dx.doi.org/10.1071/ea9870231.
Testo completoAbstract (sommario):
Pinus radiata seedlings were planted into an annual pasture at low, medium and high densities. The trees were pruned annually from year 4 and those with poor form were progressively culled until final stand densities of 75, 150 and 225 trees ha-1 were achieved 7 years after planting. The pastures were grazed by sheep from year 4. The sheep carrying capacities of the pastures declined as tree density increased because of competition between trees and pasture and also because of debris from thinning and pruning. In year 7, under the high density trees, the sheep carrying capacity of the pastures was 73% and light transmission was 69% of that of control pastures (no trees) and debris covered about 22% of the pasture. Diameter growth measurements from year 5 to 7 were 7.65, 7, 45 and 6.35 cm for low, medium and high density of trees respectively, which indicates that competition between trees had commenced at the high density (P<0.05). There was little conflict between the agricultural and forestry components at the low stand density with satisfactory production from both. This system has the potential to generate annual income to offset pine establishment and silvicultural costs while providing another source of income in the long term. It is being tried on farm scale by some landholders wishing to diversify from grazing-only enterprises.
25
Grace, B. S., R. D. B. Whalley, A. W. Sheppard e B. M. Sindel. "Managing saffron thistle in pastures with strategic grazing". Rangeland Journal 24, n. 2 (2002): 313. http://dx.doi.org/10.1071/rj02018.
Testo completoAbstract (sommario):
Saffron thistle (Carthamus lanatus L.) is a widespread and troublesome weed in grazing land throughout much of eastern Australia. Conventional control measures are not feasible in much of this area, so the prospect for controlling saffron thistle through strategic grazing with sheep was investigated. By sowing seeds, and counting seedlings that emerged, we found that as little as 2 cm of pasture cover reduced the number of seedlings that emerged by 96% compared with bare ground. Grazing experiments showed that the survival of saffron thistle rosettes was reduced by 12% in plots that were strategically rested for one month in autumn, followed by grazing at high stocking rates. Grazing in late spring, when plants produced flowering stems, killed 20% of thistles before they set seed. A comparison of thistle density and pasture composition on farms that practice strategic grazing with neighbouring farms that used continuous grazing supported these results. Pastures had few thistles when perennial grasses accounted for over 35% of groundcover. We conclude that grazing management can help control saffron thistle.
26
Maino, James L., Matthew Binns e Paul Umina. "No longer a west-side story – pesticide resistance discovered in the eastern range of a major Australian crop pest, Halotydeus destructor (Acari: Penthaleidae)". Crop and Pasture Science 69, n. 2 (2018): 216. http://dx.doi.org/10.1071/cp17327.
Testo completoAbstract (sommario):
The redlegged earth mite, Halotydeus destructor (Tucker) (Acari: Penthaleidae), is an important pest of pastures, broad-acre crops, and vegetables across southern Australia. Populations of H. destructor in Western Australia have been known to be resistant to pyrethroid and organophosphorus pesticides since 2006 and 2014, respectively. Resistant populations are currently widespread across Western Australia’s southern growing region but have, until now, remained undetected in the large south-eastern Australian range of H. destructor, despite ongoing resistance screening since 2006. Following reports of a field control failure in the Upper South East district in South Australia in 2016, resistance testing determined this South Australian population was resistant to pyrethroid and organophosphorus pesticides. The levels of resistance discovered were similar to resistant H. destructor populations in Western Australia, which are associated with chemical control failures. This work confirms for the first-time that pesticide resistant populations of H. destructor are no longer isolated to Western Australia.
27
Sanford, P., X. Wang, K. D. Greathead, J. H. Gladman e J. Speijers. "Impact of Tasmanian blue gum belts and kikuyu-based pasture on sheep production and groundwater recharge in south-western Western Australia". Australian Journal of Experimental Agriculture 43, n. 8 (2003): 755. http://dx.doi.org/10.1071/ea02226.
Testo completoAbstract (sommario):
The effect of Tasmanian blue gum (Eucalyptus globulus) belts and kikuyu (Pennisetum clandestinum) grass on livestock production and groundwater recharge was studied in the high rainfall zone (>600 mm/year) of south-western Western Australia from 1998 to 2001. The objective was to identify optimum combinations of tree belts and pasture for sustainable livestock production and the prevention of secondary salinisation. Treatments were annual pasture, in competition with trees at different orientations (east, west and south), kikuyu pasture in competition with trees at one orientation (west), compared with pasture in the absence of tree competition. Plots had 0, 20 or 36% of their area within 10 m of the tree belt where tree–pasture competition would be expected. Plots (0.48 ha) were stocked with Merino wether hoggets at 12 DSE/ha on annual pastures and 14 DSE/ha on kikuyu pastures. Additional sheep were placed on plots in spring and the annual pasture was destocked in autumn.Within the growing season, herbage mass was similar across both control treatments as a result of varying stock numbers. However, in summer and autumn the kikuyu control contained between 350 and 4900 kg DM/ha more herbage than the corresponding annual pasture. While both pastures accumulated similar amounts of herbage in 1998 and 2000, kikuyu accumulated more in 1999 (11 900 v. 9800 kg DM/ha) as a result of summer rain. Competition from tree belts significantly reduced adjacent annual pasture herbage accumulation (16% average reduction), although there was no difference among the levels of competition. Trees did not significantly affect adjacent kikuyu pasture herbage accumulation. Both carrying capacity and clean wool production per hectare were significantly higher on kikuyu pasture in 1999 and 2000. Tree competition also significantly reduced the carrying capacity of neighbouring annual and kikuyu pasture by an average of 10%. Clean wool production per hectare was significantly lower on annual pasture in combination with trees (11% reduction on average), but there was less effect of competition on kikuyu pasture. The kikuyu pasture used 115, 57 and 132 mm more water than the annual pasture in 1999, 2000 and 2001, respectively. The soil water deficit beneath the trees exceeded that below both control pastures by between 297 and 442 mm.Although the addition of tree belts to annual pasture provided substantial reductions in groundwater recharge, producers would also have to accept losses in livestock production. While kikuyu alone provided significant increases in livestock production and substantial reductions in groundwater recharge, the best compromise was kikuyu in combination with tree belts.
28
Heap, John W. "Control of Rush Skeletonweed (Chondrilla juncea) with Herbicides". Weed Technology 7, n. 4 (dicembre 1993): 954–59. http://dx.doi.org/10.1017/s0890037x00038070.
Testo completoAbstract (sommario):
A range of herbicide treatments was evaluated for long-term control of rush skeletonweed, a perennial weed of crops and pastures in North and South America, the Mediterranean region, central Europe, and Australia. Clopyralid (75 to 300 g ai/ha) and clopyralid mixtures with 2,4-D, MCPA, or dicamba were effective, resulting in survival rates of 0 to 4% for the most successful treatments applied for three consecutive seasons. Metsulfuron (9 g ai/ha) and 2,4-D (850 g ai/ha) significantly reduced survival when applied at high rates for three years. Barley yield in the season following control was increased by up to 195 to 199% of yield from untreated plots. Evidence was found for differences in herbicide susceptibility between narrowleaf and broadleaf forms of rush skeletonweed.
29
French, R. J., R. S. Malik e M. Seymour. "Crop-sequence effects on productivity in a wheat-based cropping system at Wongan Hills, Western Australia". Crop and Pasture Science 66, n. 6 (2015): 580. http://dx.doi.org/10.1071/cp14262.
Testo completoAbstract (sommario):
Western Australian grain production is dominated by wheat, but growing wheat continually in unbroken sequences leads to increasing problems with soil nutrient depletion, root and leaf disease build-up, high weed burdens, and possibly other less well-defined production constraints. These can adversely affect both production and grain quality. Including breaks in the crop sequence in the form of break crops, pasture, or fallow can reduce these problems, but these breaks can be expensive to implement, in terms of both direct cost and forgone revenue. It is therefore critical to predict the response of subsequent wheat crops to a break in order to choose crop sequences rationally. We conducted a 4-year experiment at Wongan Hills, Western Australia, evaluating how wheat productivity in a wheat-based cropping sequence is affected by including wheat, barley, lupins, triazine-tolerant and Roundup Ready® canola, oaten hay, volunteer pasture, serradella pasture, and chemical fallow. Wheat yield responded positively to fallow, lupins, oaten hay, volunteer pastures and serradella but not to barley or canola when compared with continuous wheat. Responses depended on seasonal conditions; in a dry year, a very large response occurred after fallow but not after lupin or serradella, whereas in a wetter year, there were large responses after these crops. Fallowing, cutting hay, crop-topping lupins, and spray-topping volunteer and serradella pasture all reduced seedset of annual ryegrass dramatically, and reduced weed competition was a major contributor to the observed break crop responses. Nitrogen fixation by lupins and serradella and water storage by fallow in a dry year were also important, but soilborne diseases did not contribute to wheat yield responses. Some yield responses persisted for at least 3 years, and the contribution of effects of weed competition to yield responses increased over this time. These results emphasise the importance of understanding which productivity constraints are present in a cropping system at a given time when deciding whether a break is necessary and which is the most appropriate break. The results also emphasise the importance of managing the wheat crop after a break to maximise the response and its longevity.
30
Ridsdill-Smith, T. J., e C. C. Pavri. "Controlling redlegged earth mite, Halotydeus destructor (Acari: Penthaleidae), with a spring spray in legume pastures". Crop and Pasture Science 66, n. 9 (2015): 938. http://dx.doi.org/10.1071/cp14272.
Testo completoAbstract (sommario):
The use of a TIMERITE® spring spray to control redlegged earth mite (RLEM), Halotydeus destructor (Tucker) (Acari: Penthaleidae), in annual pastures was evaluated on farms across Australia. RLEM populations in autumn in the treatments sprayed in spring 1998 and 1999 were 97% lower in 1999 and 97% in 2000 in the western region (Western Australia), and 93% lower in 1999 and 93% in 2000 in the eastern region (Victoria, New South Wales and South Australia). At sites in the west, control of RLEM resulted in significant increases in subterranean clover seed yield in 1999 and in clover seedling numbers in autumn 1999 and 2000. Penthaleus major (blue oat mite) populations in autumn were 60% lower in sprayed treatments, but Sminthurus viridis (lucerne flea) populations were not affected. Differences in weather between the west (where there is a hot, dry summer) and the east (where temperature and rainfall regimes are more variable in spring and early summer) seem to cause greater RLEM control and greater benefits in subterranean clover seed yield and seedling numbers with a spring spray in the west.
31
Owen, Mechelle J., e Stephen B. Powles. "The frequency of herbicide-resistant wild oat (Avena spp.) populations remains stable in Western Australian cropping fields". Crop and Pasture Science 67, n. 5 (2016): 520. http://dx.doi.org/10.1071/cp15295.
Testo completoAbstract (sommario):
Avena is a problematic weed of cropping regions of southern Australia and many areas of the world. In 2010, a random survey was conducted across 14 million hectares of the Western Australian grain belt to monitor the change in herbicide resistance levels by comparing resistance frequency results with a survey conducted in 2005. Screening Avena populations with herbicides commonly used to control this weed revealed that 48% of Avena populations displayed resistance to the commonly used acetyl-Co A carboxylase-inhibiting herbicides, which was lower than that found in 2005 (71%). The broad-spectrum herbicides glyphosate and paraquat provided good control of all Avena populations. Resistance to acetolactate synthase-inhibiting herbicides and to flamprop were detected for the first time in Western Australia in this survey. Therefore, a wide range of weed management options that target all phases of the cropping program are needed to sustain these cropping systems in the future.
32
Mears, PT, DW Hennessy, DW Williamson e DJ McLennan. "Growth and forage intake of Hereford steers fed giant Parramatta grass hay (Sporobolus indicus) and the effects of dietary nitrogen supplements". Australian Journal of Experimental Agriculture 36, n. 1 (1996): 1. http://dx.doi.org/10.1071/ea9960001.
Testo completoAbstract (sommario):
Giant Parramatta grass (GPG) (Sporobolus indicus var. Major), a serious weed of pastures of subtropical Australia, is poorly grazed by cattle leading to reports of low production on badly infested pastures. To provide information for cattle producers we recorded feed intake and liveweight change of steers in a 56-day study, and nitrogen (N) excretion over 5 days when GPG was fed as hay. Data were compared with those for GPG hay supplemented with urea (7 g urea/kg hay), or with urea and cottonseed meal (CSM; 750 g/steer.day), and with those for steers fed a native pasture (NP) hay, which included a legume (Aeschynornene falcata). Each steer was also fed daily a mixed mineral supplement of 35 g sprinkled on the hay. Urea increased (P<0.01) daily GPG hay intake from 4.2 to 5.0 kg/steer, but there was no significant increase in intake (4.5kg/steer) when CMS was included. Steers on NP hay had a mean daily intake of 5.1 kg/steer which was similar to that of steers offered GPG hay + urea. Urea increased daily liveweight gain from 323 to 555 g/steer (P<0.05); the addition of CSM further increased (P<0.05) the gain to 676 g/steer. Steers on NP hay had a mean daily liveweight gain of 480 g/steer. The gain for steers offered CSM with GPG hay + urea was higher than that predicted by GrazFeed (1993) for a low digestible, low NP hay, supplemented with urea and CSM. Improved production of steers through using nitrogen supplements, may provide an opportunity for cattle to use this weed as a hay or silage in pastures as part of a program to control weed ingress in subtropical pastures.
33
Bailey, P., J.-L. Sagliocco, J. Vitou e D. Cooke. "Prospects for biological control of cutleaf mignonette, Reseda lutea (Resedaceae), by Baris picicornis and Bruchela spp. in Australia". Australian Journal of Experimental Agriculture 42, n. 2 (2002): 185. http://dx.doi.org/10.1071/ea01059.
Testo completoAbstract (sommario):
In South Australia, Reseda lutea is abundant, invading pastures and crops on calcareous soils while in its native Mediterranean range it is uncommon in occurrence and is not reported as a weed of cultivated crops. Its invasive behaviour in South Australia may be attributed to vegetative growth of root fragments spread by cultivation, while propagation by seed is of minor importance. Surveys in Spain, Portugal, Morocco, France, Turkey and Israel indicated that agronomic differences, particularly depth of cultivation and seeding rates of cereals may explain why it is not a crop weed in these countries. Another difference is that plants in the region of origin have an associated fauna not present in Australia. These potential biological control agents include a root-boring weevil, Baris picicornis, flower- and seed-feeding urodontids, Bruchela suturalis and B. rufipes, and a leaf spot pathogen,Cercospora resedae. Baris picicornis was introduced from France and Turkey, under quarantine, to Australia but laboratory specificity-testing demonstrated that it could complete its life cycle on 2 commercially grown cultivars of Brassica rapa (choy sum and Chinese cabbage). Because of this, it is not proposed to release B. picicornis in Australia at present. Bruchela suturalis was also introduced into Australian quarantine from France but attempts to change its annual life cycle to Southern Hemisphere seasons were not successful, and a culture could not be established. Both Baris picicornis and Bruchela spp. remain promising agents, and further work on their introduction is justified by their potential for biological control of R. lutea.
34
Malik, Raj S., Mark Seymour, Robert J. French, John A. Kirkegaard, Roger A. Lawes e Mark A. Liebig. "Dynamic crop sequencing in Western Australian cropping systems". Crop and Pasture Science 66, n. 6 (2015): 594. http://dx.doi.org/10.1071/cp14097.
Testo completoAbstract (sommario):
During the last two decades in Western Australia, the traditional mixed farming system has been increasingly displaced by intensive crop sequences dominated by wheat. Intensive wheat sequences are usually maintained by using suitable breaks, including pasture, fallow, or alternative cereal, oilseed and legume crops, to control weeds and disease, or maintain the supply of nitrogen to crops. New cereal fungicide options may also assist to maintain intensive cereal systems by suppressing soilborne cereal diseases. To guide the successful diversification of intensive cereal systems, we evaluated the effect of a 2-year experimental matrix of 10 different sequence options. Wheat in the sequence was treated with the fluquinconazole fungicide Jockey (wheat + J) to control soilborne pathogens, or with the usual seed dressing of flutriafol fungicide (wheat – J), used for control of bunts and smuts only. The sequences were wheat + J, wheat – J, barley, grain oats, oaten hay, canola, lupin, field pea, oat–vetch green manure, bare fallow) in which all treatment combinations were grown in year 2 following the same 10 treatments in year 1. In year 3, wheat + J was grown across the entire area as the test crop. In year 2, grain yields of all crops were reduced when crops were grown on their own residues, including wheat (22% reduction), canola (46%), lupin (40%) and field pea (51%). Wheat + J significantly outyielded wheat – J by 300 kg ha–1 in year 1 (14% increase) and 535 kg ha–1 in year 2 (26% increase). Wheat + J was more responsive to break crops than wheat – J in both year 1 and year 2. Break crops sown in year 1, such as canola, fallow, field pea, lupin and oaten hay, continued to have a positive effect on year 3 wheat + J yields. This study has highlighted the importance of break crops to following cereal crops, and provided an example in which a seed-dressing fungicide fluquinconazole in the presence of low levels of disease consistently improved wheat yields.
35
Riethmuller, G. P., A. Hashem e S. M. Pathan. "Chemical and Non-Chemical Weed Control in Wide Row Lupins and Chickpeas in Western Australia". Australian Journal of Multi-Disciplinary Engineering 7, n. 1 (gennaio 2009): 15–26. http://dx.doi.org/10.1080/14488388.2009.11464795.
Testo completo
36
Norton, M. R., M. L. Mitchell, E. Kobelt e E. Hall. "Evaluation of native and introduced grasses for low-input pastures in temperate Australia: experimental approach, site and genotype descriptions". Rangeland Journal 27, n. 1 (2005): 11. http://dx.doi.org/10.1071/rj05002.
Testo completoAbstract (sommario):
This paper describes the experimental methodology, sites, seasonal conditions and germplasm used in the Australian Native and Low Input Grass Network (NLIGN). In 1998, eight sites were established across the temperate pastoral zone of southern Australia. These were located at Armidale, Binya, Sutton and Trangie in NSW; Springhurst in Victoria; Jericho in Tasmania; Flaxley in South Australie and Kendenup in Western Australia. A total of 62 lines were evaluated, of which, 29 were Australian native grasses and 33 were introduced. With differences in seed size among species and a lack of information on dormancy and germination characteristics of the native plants, seedlings were transplanted into the field on weed-mat as spaced plants. Lines were compared over a 3-year period from 1998 to 2001. Methods used for determination of forage production, persistence and palatability are described. Information detailing the original collection sites of the germplasm, a list of NLIGN sites where each genotype was evaluated, as well as a detailed description of sites and seasonal conditions is also presented.
37
Waller, R. A., e P. W. G. Sale. "Persistence and productivity of perennial ryegrass in sheep pastures in south-western Victoria: a review". Australian Journal of Experimental Agriculture 41, n. 1 (2001): 117. http://dx.doi.org/10.1071/ea00049.
Testo completoAbstract (sommario):
Loss of perennial ryegrass (Lolium perenne L.) from the pasture within several years of sowing is a common problem in the higher rainfall (550–750 mm annual rainfall), summer-dry regions of south-eastern Australia. This pasture grass came to Australia from northern Europe, where it mostly grows from spring to autumn under mild climatic conditions. In contrast, the summers are generally much drier and hotter in this region of south-eastern Australia. This ‘mismatch’ between genotype and environment may be the fundamental reason for the poor persistence. There is hope that the recently released cultivars, Fitzroy and Avalon, selected and developed from naturalised ryegrass pastures in south-eastern Australia for improved winter growth and persistence will improve the performance of perennial ryegrass in the region. Soon-to-be released cultivars, developed from Mediterranean germplasm, may also bridge the climatic gap between where perennial ryegrass originated and where it is grown in south-eastern Australia. Other factors that influence perennial ryegrass persistence and productivity can be managed to some extent by the landholder. Nutrient status of the soil is important since perennial ryegrass performance improves relative to many other pasture species with increasing nitrogen and phosphorus supply. It appears that high soil exchangeable aluminium levels are also reducing ryegrass performance in parts of the region. The use of lime may resolve problems with high aluminium levels. Weeds that compete with perennial ryegrass become prevalent where bare patches occur in the pasture; they have the opportunity to invade pastures at the opening rains each year. Maintaining some herbage cover over summer and autumn should reduce weed establishment. Diseases of ryegrass are best managed by using resistant cultivars. Insect pests may be best managed by understanding and monitoring their biology to ensure timely application of pesticides and by manipulating herbage mass to alter feed sources and habitat. Grazing management has potential to improve perennial ryegrass performance as frequency and intensity of defoliation affect dry matter production and have been linked to ryegrass persistence, particularly under moisture deficit and high temperature stress. There is some disagreement as to the merit of rotational stocking with sheep, since the results of grazing experiments vary markedly depending on the rotational strategy used, climate, timing of the opening rains, stock class and supplementary feeding policy. We conclude that flexibility of grazing management strategies is important. These strategies should be able to be varied during the year depending on climatic conditions, herbage mass, and plant physiology and stock requirements. Two grazing strategies that show potential are a short rest from grazing the pasture at the opening rains until the pasture has gained some leaf area, in years when the opening rains are late. The second strategy is to allow ryegrass to flower late in the season, preventing new vegetative growth, and perhaps allowing for tiller buds to be preserved in a dormant state over the summer. An extension of this strategy would be to delay grazing until after the ryegrass seed heads have matured and seed has shed from the inflorescences. This has the potential to increase ryegrass density in the following growing season from seedling recruitment. A number of research opportunities have been identified from this review for improving ryegrass persistence. One area would be to investigate the potential for using grazing management to allow late development of ryegrass seed heads to preserve tiller buds in a dormant state over the summer. Another option is to investigate the potential, and subsequently develop grazing procedures, to allow seed maturation and recruitment of ryegrass seedlings after the autumn rains.
38
Hashem, Abul, R. Michael Collins e David G. Bowran. "Efficacy of Interrow Weed Control Techniques in Wide Row Narrow-Leaf Lupin". Weed Technology 25, n. 1 (marzo 2011): 135–40. http://dx.doi.org/10.1614/wt-d-10-00081.1.
Testo completoAbstract (sommario):
The sharp decline in the area of lupin grown in Australia is partly attributed to the failure to control herbicide-resistant weeds in narrow-leaf lupin crops grown with the conventional 25-cm-wide row spacing. Growing lupin with wider row spacing allows for interrow weed control by nonselective herbicides using a sprayshield or physical methods. During 2003 to 2006, two experiments conducted at five sites evaluated the efficacy of interrow weed control techniques in narrow-leaf lupin crops grown in 55- to 65-cm-wide rows within the Western Australia wheatbelt. Interrow herbicides were applied POST using sprayshields, intrarow herbicides were banded on lupin rows at seeding, and interrow weeds were mowed using a garden mower. The main weed species at each site was rigid ryegrass, blue lupin, or wild radish. Paraquat plus diquat applied on the interrow of the lupin crop with sprayshields controlled up to 100% of weeds between rows, leading to increases in lupin grain yield in most of the sites. Glyphosate alone, a mixture of glyphosate plus metribuzin, and glyphosate followed by paraquat plus diquat also controlled interrow weeds, but did not increase lupin grain yield at any site. Thus, paraquat plus diquat is a better choice for interrow weed control in wide row lupin than glyphosate. Mowing did not improve weed control, but mowing followed by paraquat plus diquat increased lupin grain yield at one site. Regression models predicted that there was a strong relationship between weed biomass and lupin grain yield.
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Park, C. Y., M. A. Lee, M. Nam, E. H. Park, Y. S. Bae, S. H. Lee, J. S. Kim e D. Y. Won. "First Report of Clover yellow vein virus on White Clover (Trifolium repens) in South Korea". Plant Disease 98, n. 10 (ottobre 2014): 1450. http://dx.doi.org/10.1094/pdis-05-14-0540-pdn.
Testo completoAbstract (sommario):
White clover (Trifolium repens L.) is a herbaceous, perennial plant that has become one of the most widely distributed legumes in the world. It is extensively used in grass-legume pastures, but also has the potential to invade agricultural lands and natural ecosystems. White clover is a well-known natural host for Alfalfa mosaic virus (AMV), Clover yellow vein virus (ClYVV), Soybean dwarf virus (SbDV), Beet western virus (BWYV), Tomato spotted wilt virus (TSWV), Zucchini yellow mosaic virus (ZYMV), etc (1). In July 2013, during a survey to determine the presence of different viruses infecting weed plants in South Korea, three white clover leaf samples showing yellow mosaic symptoms were collected from Taean County, South Chungcheong Do Province, South Korea. In order to identify the infecting virus, total RNA from three leaf samples was extracted using the Tri-reagent (MRC Reagent, Inc., OH) as described by the manufacturer, and was applied to the large-scale oligonucleotide (LSON) chip (3), wherein probes specific to a ClYVV isolate produced a positive reaction. All three samples tested were positive for ClYVV. To confirm this result, ClYVV-specific primers were designed using the sequences of four ClYVV isolates from NCBI (GenBank Accession Nos. AF185959, AF203536, DQ333346, and NC003536). Total RNA was extracted from symptomatic white clover samples using Easy-Spin Total RNA Extraction Kit (iNtRon, Daejeon, Korea) and used as template for RT-PCR. The positive control RNA was used from ClYVV GM isolate (KF975894) and negative control RNA used symptomless white clover plants. The ClYVV coat protein (CP) gene was amplified by RT-PCR using the specific primer pairs ClYVV-CP-F / ClYVV-CP-R (5′-CAAGAGCAGCACGATGAG-3′ and 5′-CTCGCTCTATAAAGATCAGAT-3′). DNA fragments of the expected size (1,042 bp) were obtained from the white clover Korea isolate (AB930132), and the PCR product was cloned into a T&A cloning vector (RBC Bioscience, Taipei, Taiwan) and sequenced directly in both directions. BLAST analyses of the nucleotide sequence CP gene fragments revealed the highest identity with 98% with other ClYVV isolates (AF203536). To determine the experimental host range of the ClYVV Korea isolate, we inoculated five species (Chenopodium amaranticolor, C. quinoa, Nicotiana clevelandii, N. benthamiana, and Trifolium repens) in three families using this isolate. All test plants were mechanically inoculated with 0.1 M phosphate buffered saline (Takara, Tokyo, Japan). Each test plant was inoculated nine times and grown in a greenhouse maintained at 27 to 33°C. Necrotic local lesions were produced on inoculated leaves of C. amaranticolor, C. quinoa, and N. clevelandii 4 to 6 days post-inoculation. After 10 to 14 days, C. amaranticolor and C. quinoa showed systemic chlorotic spot symptoms, and N. clevelandii, N. benthamiana, and T. repens showed chlorotic spot, mild mosaic, and mosaic in the upper leaves, respectively. Up to now, in South Korea, ClYVV has been detected in gladiolus (Gladiolus gandavensis) (3) and soybean (Glycine max) (4). ClYVV can be easily transmitted by insect, aphid, or mechanical inoculation and has a host range including tobacco, soybean, etc. The presence of ClYVV could become an important threat to crop production in South Korea. To our knowledge, this is the first report of a ClYVV infection of the white clover plant in South Korea. References: (1) B. L. Denny and P. L. Guy. Australas. Plant Pathol. 38:270, 2009. (2) M. Nam et al. Plant Pathol. J. 30:51, 2014. (3) I. S. Park et al. Korean J. Plant Pathol. 14:74, 1998. (4) J. C. Shin et al. Plant Dis. 98:1283, 2014.
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Spennemann, D. H. R., e L. R. Allen. "Feral olives ( Olea europaea) as future woody weeds in Australia: a review". Australian Journal of Experimental Agriculture 40, n. 6 (2000): 889. http://dx.doi.org/10.1071/ea98141.
Testo completoAbstract (sommario):
Olives (Olea europaea ssp. europaea), dispersed from 19th century orchards in the Adelaide area, have become established in remnant bushland as a major environmental weed. Recent expansion of the Australian olive industry has resulted in the widespread planting of olive orchards in South Australia, Victoria, New South Wales, Western Australia, Queensland and parts of Tasmania. This paper reviews the literature on the activity of vertebrate (principally avian) olive predators and their potential as vectors for spreading this plant into Australian remnant bushland. The effects of feralisation on the olive plant, which enhances its capacity for dispersal as a weed, place wider areas of south-eastern Australia at risk. A number of approaches for the control of olives as woody weeds are addressed. Proponents of new agricultural crops have moral and environmental obligations to assess the weed potential of these crops.
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Francis, Ardath, Stephen J. Darbyshire, Anne Légère e Marie-Josée Simard. "The Biology of Canadian Weeds. 151. Erodium cicutarium (L.) L'Hér. ex Aiton". Canadian Journal of Plant Science 92, n. 7 (novembre 2012): 1359–80. http://dx.doi.org/10.4141/cjps2012-076.
Testo completoAbstract (sommario):
Francis, A., Darbyshire, S. J., Légère, A. and Simard, M.-J. 2012. The Biology of Canadian Weeds. 151. Erodium cicutarium (L.) L'Hér. ex Aiton. Can. J. Plant Sci. 92: 1359–1380. Stork's bill, Erodium cicutarium, is an annual weed of the geranium family (Geraniaceae), native to Mediterranean Europe, North Africa and western Asia. It has spread widely to temperate regions of both hemispheres, in particular to semi-arid ranges and prairies where it is frequently a dominant weed. In western Canada, it has increased in importance as a weed of cereal, canola, legume, sugarbeet and potato crops, particularly with the adoption of conservation tillage, and is both a field weed and seed contaminant of forage crops. The species had been sporadically collected in Québec since 1874 from cultivated fields (oats, potatoes, corn), but it recently appeared in experimental plots grown in corn, soybean, and red clover in eastern Québec, suggesting its potential as a serious weed. Outside of Canada, it is found in a range of crops, and has been host to viral, fungal and insect pathogens that can cause damage to crops and pastures. The plant's early germination, rapid growth and prolific seed production give it a competitive advantage in crops. In spring crops, the weed may be past the stage for optimal control by the time that the crop has reached the stage when herbicides are normally applied. Control may consequently require an extensive and often costly integrated weed management system. In semi-arid grazing areas it probably displaced some native vegetation, but has also become an important forage plant and a source of food for native wildlife. Its antioxidant and other chemical properties have drawn attention to potential medicinal and other beneficial uses.
42
Martin, Gary R., Laurie E. Twigg e Lina Zampichelli. "Seasonal changes in the diet of the European rabbit (Oryctolagus cuniculus) from three different Mediterranean habitats in south-western Australia". Wildlife Research 34, n. 1 (2007): 25. http://dx.doi.org/10.1071/wr06044.
Testo completoAbstract (sommario):
Abstract.�Seasonal changes in the diet of rabbits from three temperate (Mediterranean) areas in south-western Australia were identified using microscopic determination of the percentage occurrence of various food groups in sampled stomachs. The sites differed in soil type and in the availability of summer perennials, native vegetation bush remnants (size of, and number of plant species), improved pastures, and summer rainfall, and hence, enabled a comparison of the diet of rabbits from the different vegetation communities. Although the diet of these rabbits was quite flexible, with some switching in food items occurring between seasons, there were marked differences in the proportion of monocotyledonous and dicotyledonous species eaten in each habitat. There was a strong reliance on seeds (1-5 species) during late spring and summer in all three habitats. Guildford grass (Romulea rosea) leaf and corms were a major component of the diet in the two habitats where this species was common. Further, as a result of the summer die-off of pasture species, there was a shift in where rabbits sourced food items during winter and summer. Pasture species were eaten during winter, but rabbits fed mainly on those dicotyledons found only in the surrounding scrub during summer. This suggests that rabbits may impact negatively upon such remnant vegetation at this time. Rabbits in all three habitats consumed several plant species with high water content (>54%) during summer, presumably to help maintain their water balance. Rabbits also consumed the seeds and foliage of several weed/nuisance species in each habitat, but any role of rabbits in weed dispersal was not determined.
43
Hacker, Ronald B., Ian D. Toole, Gavin J. Melville, Yohannes Alemseged e Warren J. Smith. "Managing competitive interactions to promote regeneration of native perennial grasses in semi-arid south-eastern Australia". Rangeland Journal 39, n. 1 (2017): 59. http://dx.doi.org/10.1071/rj16048.
Testo completoAbstract (sommario):
Treatments to reduce available soil nitrogen and achieve specified levels of weed control were evaluated for their capacity to promote regeneration of native perennial grasses in a degraded semi-arid woodland in central-western New South Wales. Treatments were factorial combinations of nitrogen-reduction levels and weed-control levels. The four levels of nitrogen reduction were no intervention, and oversowing of an unfertilised summer crop, an unfertilised winter crop or an unfertilised perennial grass. The three weed-control levels were defined by the outcome sought rather than the chemical applied and were nil, control of annual legumes and control of all annual species (AA). Regeneration of perennial grasses, predominantly Enteropogon acicularis, was promoted most rapidly by the AA level of weed control with no introduction of sown species. Sown species negated the benefits of weed control and limited but did not prevent the regeneration of native perennials. Sown species also contributed substantially to biomass production, which was otherwise severely limited under the AA level of weed control, and they were effective in reducing soil nitrogen availability. Sown species in combination with appropriate herbicide use can therefore maintain or increase available forage in the short–medium term, permit a low rate of native perennial grass recruitment, and condition the system (by reducing soil mineral nitrogen) for more rapid regeneration of native perennials should annual sowings be discontinued or a sown grass fail to persist. Soil nitrate was reduced roughly in proportion to biomass production. High levels of soil nitrate did not inhibit native perennial grass regeneration when biomass was suppressed by AA weed control, and may be beneficial for pastoral production, but could also render sites more susceptible to future invasion of exotic annuals. The need for astute grazing management of the restored grassland is thus emphasised. This study was conducted on a site that supported a remnant population of perennial grasses. Use of the nitrogen-reduction techniques described may not be appropriate on sites where very few perennial grass plants remain.
44
Bach, Thomas M., Christian A. Kull e Haripriya Rangan. "From killing lists to healthy country: Aboriginal approaches to weed control in the Kimberley, Western Australia". Journal of Environmental Management 229 (gennaio 2019): 182–92. http://dx.doi.org/10.1016/j.jenvman.2018.06.050.
Testo completo
45
Scott, John K., Kathryn L. Batchelor e Bruce L. Webber. "Long term monitoring of recruitment dynamics determines eradication feasibility for an introduced coastal weed". NeoBiota 50 (2 settembre 2019): 31–53. http://dx.doi.org/10.3897/neobiota.50.35070.
Testo completoAbstract (sommario):
Bitou bush (Chrysanthemoides monilifera subsp. rotundata) is a Weed of National Significance in Australia and has impacted a significant portion of the eastern coastline. Its discovery in Western Australia was, therefore, a cause for concern. Assessment and control of the isolated and well-defined population began in 2012. To assess the feasibility of eradication in Western Australia as a management outcome for bitou bush, we applied a rigorous data-driven quantification and prediction process to the control program. Between 2012 and 2018 we surveyed over 253 ha of land and removed 1766 bitou bush plants. Approximately 97 person-days were spent over the six years of survey. We measured the seed bank viability for five years starting in 2013, with the 2017 survey results indicating a decline of mean viable seeds/m2 from 39.3 ± 11.4 to 5.7 ± 2.2. In 2018 we found only ten plants and no newly recruited seedlings in the population. No spread to other areas has been recorded. Soil core studies indicate that the soil seed bank is unlikely to persist beyond eight years. Eradication of the population in Western Australia, defined as five years without plants being detected, therefore remains a realistic management goal. The information generated from the documentation of this eradication program provides invaluable insight for weed eradication attempts more generally: novel detection methods can be effective in making surveys more efficient, all survey methods are not entirely accurate and large plants can escape detection, bitou bush seeds persist in the soil but become effectively undetectable at low densities, and migration of seed was unquantifiable, possibly compromising delimitation. Continued monitoring of the Western Australian population will determine how much of a risk these factors represent to eradication as the outcome of this management program.
46
Johnston, W. H., P. S. Cornish, T. B. Koen e V. F. Shoemark. "Eragrostis curvula (Schrad.) Nees. complex pastures in southern New South Wales, Australia: a comparison of Eragrostis curvula cv. Consol and Medicago sativa L. cv. Nova under intensive rotational management". Australian Journal of Experimental Agriculture 45, n. 10 (2005): 1255. http://dx.doi.org/10.1071/ea04080.
Testo completoAbstract (sommario):
The productivity, carrying capacity and liveweight performance of wether sheep grazing pastures of Eragrostis curvula cv. Consol and Medicago sativa cv. Nova, which were also sown with annual grasses and Trifolium subterraneum, were compared under an intensive 4-paddock rotational grazing regime in a ‘put-and-take’ grazing experiment at Wagga Wagga, New South Wales from November 1993 to August 1996. The productivity of the pastures was broadly similar, with production peaks of >1000 kg/ha in winter and >3000 kg/ha in spring and summer in paddocks that had been spelled for 6 weeks. Although annual species contributed a high proportion of the total herbage mass in spring, over the remainder of the year, both pastures were dominated by their respective perennials. E. curvula maintained an average plant density of approximately 20 plants/m2. The density of M. sativa declined noticeably during the 3 years, and at the end of the experiment M. sativa plants in 1 replicate of the experiment were killed by rising groundwater and dryland salinity. The long-term average stocking rate of E. curvula and M. sativa pastures were similar (12.1 v. 12.5 sheep/ha) and both pastures were capable of sustaining high stocking rates for lengthy periods in spring and summer. Sheep grazing M. sativa tended to be heavier than animals grazing E. curvula, and they produced, on average, 1.1 kg (or 21%) more wool. However, M. sativa was more difficult to establish and its costs for weed and insect control were higher. Therefore, although it was more productive, it might not have been the most economically viable of the 2 pastures. The implications of the findings were discussed within a whole-farm context and it was concluded that E. curvula has a complimentary role to M. sativa for sowing on landscapes and in situations to which M. sativa is poorly adapted.
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Monjardino, M., D. J. Pannell e S. B. Powles. "The economic value of haying and green manuring in the integrated management of annual ryegrass and wild radish in a Western Australian farming system". Australian Journal of Experimental Agriculture 44, n. 12 (2004): 1195. http://dx.doi.org/10.1071/ea03144.
Testo completoAbstract (sommario):
Most cropping farms in Western Australia must deal with the management of herbicide-resistant populations of weeds such as annual ryegrass (Lolium rigidum) and wild radish (Raphanus raphanistrum). Farmers are approaching the problem of herbicide resistance by adopting integrated weed management systems, which allow weed control with a range of different techniques. These systems include non-herbicide methods ranging from delayed seeding and high crop seeding rates to the use of non-cropping phases in the rotation. In this paper, the Multi-species RIM (resistance and integrated management) model was used to investigate the value of including non-cropping phases in the crop rotation. Non-crop options investigated here were haying and green manuring. Despite them providing excellent weed control, it was found that inclusion of these non-cropping phases did not increase returns, except in cases of extreme weed numbers and high levels of herbicide resistance.
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Vitelli, Joseph S., Barbara A. Madigan e Peter E. van Haaren. "Control Techniques and Management Strategies for the Problematic Navua sedge (Cyperus aromaticus)". Invasive Plant Science and Management 3, n. 3 (novembre 2010): 315–26. http://dx.doi.org/10.1614/ipsm-d-09-00036.1.
Testo completoAbstract (sommario):
AbstractNavua sedge, a member of the Cyperaceae family, is an aggressive weed of pastures in Fiji, Sri Lanka, the Malay Peninsula, Vanuatu, Samoa, the Solomon Islands, and Tahiti and is now a weed of pastures and roadsides in north Queensland, Australia. Primarily restricted to areas with an annual rainfall exceeding 2,500 mm (98.4 in), Navua sedge is capable of forming dense stands, smothering many tropical pasture species. Seventeen herbicides were field tested at three sites in north Queensland, with glyphosate, halosulfuron, hexazinone, imazapic, imazapyr, or MSMA as the most effective for Navua sedge control. Environmental problems, such as persistence in soil, lack of selectivity, and movement off-site, may occur using some herbicides at the predicted 90% lethal concentration (LC90) control level rates. A seasonality trial using halosulfuron (97.5 g ai ha−1[1.4 oz ac−1]) gave better Navua sedge control (84%) by spraying in March to September than by spraying at other times (50%). In a frequency trial, sequential glyphosate applications (2,160 g ae ha−1) every 2 mo was more effective for continued Navua sedge control (67%) than a single application of glyphosate (36%), although loss of ground cover would occur. In a management trial, single applications of glyphosate (2,160 to 3,570 g ae ha−1) using either a rope wick, ground foliar spraying, or a rotary rope wick gave 59 to 73% control, whereas other treatments (rotary hoe, 3%; slashing, −13%; crushing, −30%) were less effective. In a second management trial, four monthly rotary wick applications were much more effective (98%) than four monthly crushing applications (42%). An effective management plan must include the application of regular herbicide treatments to eliminate Navua sedge seed being added to the soil seed bank. Treatments that result in seed burial, for example, discing, are likely to prolong seed persistence and should be avoided. The sprouting activity of vegetative propagules and root fragmentation also needs to be considered when selecting control options.
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Borger, Catherine P. D., Abul Hashem e Shahab Pathan. "Manipulating Crop Row Orientation to Suppress Weeds and Increase Crop Yield". Weed Science 58, n. 2 (giugno 2010): 174–78. http://dx.doi.org/10.1614/ws-09-094.1.
Testo completoAbstract (sommario):
Crop rows oriented at a right angle to sunlight direction (i.e., east–west within the winter cropping system in Western Australia) may suppress weed growth through greater shading of weeds in the interrow spaces. This was investigated in the districts of Merredin and Beverley, Western Australian (latitudes of 31° and 32°S) from 2002 to 2005 (four trials). Winter grain crops (wheat, barley, canola, lupines, and field peas) were sown in an east–west or north–south orientation. Within wheat and barley crops oriented east–west, weed biomass (averaged throughout all trials) was reduced by 51 and 37%, and grain yield increased by 24 and 26% (compared with crops oriented north–south). This reduction in weed biomass and increase in crop yield likely resulted from the increased light (photosynthetically active radiation) interception by crops oriented east–west (i.e., light interception by the crop canopy as opposed to the weed canopy was 28 and 18% greater in wheat and barley crops oriented east–west, compared with north–south crops). There was no consistent effect of crop row orientation in the canola, field pea, and lupine crops. It appears that manipulation of crop row orientation in wheat and barley is a useful weed-control technique that has few negative effects on the farming system (i.e., does not cost anything to implement and is more environmentally friendly than chemical weed control).
50
Seymour, M. "Narbon bean (Vicia narbonensis) agronomy in south-western Australia". Australian Journal of Experimental Agriculture 46, n. 10 (2006): 1355. http://dx.doi.org/10.1071/ea04091.
Testo completoAbstract (sommario):
Narbon bean (Vicia narbonensis L.) shows promise as a fodder, green manure and grain crop in south-western Australia. This study examines the effect of time of sowing (2 experiments), plant density (3 experiments) and reaction to herbicides (4 experiments on tolerance to herbicides and 1 experiment on removing narbon bean from a wheat crop) in 10 separate field experiments sown at 4 locations in the mallee region of Western Australia from 1998 to 2001. Narbon bean was found to be unresponsive to changes in sowing date with yield maintained until the first week of June. The optimum plant density (90% of fitted maximum) for seed yield was found to be 31 plants/m2, equivalent to sowing rates in the range of 75–100 kg/ha. A wide range of herbicides applied either before sowing or immediately after sowing and before emergence had no significant effect on grain yield. These included simazine (750 g a.i./ha), cyanazine (1.25 kg a.i./ha) and diuron (500 g a.i./ha), which were applied immediately before sowing, and imazethapyr (29 g a.i./ha), which was applied after sowing, before emergence. Diflufenican (75 g a.i./ha) was found to be the only available option for post-emergence control of broadleaf weeds. The use of the non-selective herbicides glyphosate (450 g a.i./L) and Sprayseed 250 (paraquat 135 g a.i./L and diquat 115 g a.i./L) as post-emergence herbicides was found to be unpredictable at a range of application rates. Results ranged from a yield loss of 47% to a yield increase of 23%. In an experiment to test a range of herbicides for the selective control of narbon bean within a wheat crop, numerous herbicides were found to effectively remove volunteer narbon bean indicating that narbon bean is unlikely to become a weed in most cereal cropping systems.