bluuebunny/crossref_metadata_2025 huggingface dataset:
Above‐ and Belowground Trophic Interactions on Creeping Thistle(Cirsium arvense)in High‐ and Low‐Diversity Plant Communities: Potential for Biotic Resistance?
Authors: Bezemer T. M. , Gra¸a O. , Rousseau P. , van der Putten W. H.
Published: March 2004

Abstract:The capacity of local communities to control introduced plants is called biotic resistance. Biotic resistance has been almost exclusively tested for plant competition and aboveground herbivores and pathogens, while neglecting root herbivores and soil pathogens. Here, we present biotic resistance by above‐ and belowground herbivores in concert, and relate the abundance of the plant enemies to the species diversity of the local plant communities. The study was carried out in a 7‐year‐old biodiversity field experiment. We used creeping thistle(Cirsium arvense)as a model, and quantified sap‐sucking herbivores: aboveground aphids, their antagonists, and root‐feeding nematodes. As plant diversity treatments, we used field plots sown with high (15 plant species, HSD) or low (4 plant species, LSD) diverse seed mixtures in 1996 and that were not weeded. Creeping thistle became established spontaneously at the start of the experiment. In 2002, in HSD plots, 90 % of the plant community was made up by 11 species, compared to seven species in LSD plots. No differences were found forC. arvenseabundance or biomass. Aboveground, three aphid species were found onC. arvense‐Uroleucon cirsii, Aphis fabae,andMacrosiphum euphorbiae,but the latter was found only in low densities. Significantly more aphid species were found on individual plants in HSD plots. Moreover, in HSD plots, on average 10 % of aphids were parasitized, while no parasitism was observed in LSD plots. In the root zone ofC. arvense,significantly more nematodes were found in HSD than in LSD plots, and a significantly higher proportion of those nematodes were plant parasites. The dominant plant parasitic nematode in both treatments wasParatylenchus.We conclude that biotic resistance by natural enemies may be enhanced by plant species diversity, but that above‐ and belowground sap‐sucking herbivores do not necessarily have to respond similarly to the diversity of the surrounding plant community.
Involvement of the Plasma Membrane Ca2+‐ATPase in the Short‐Term Response of Arabidopsis thaliana Cultured Cells to Oligogalacturonides
Authors: Romani G. , Bonza M. C. , Filippini I. , Cerana M. , Beffagna N. , de Michelis M. I.
Published: March 2004

Abstract: Treatment of Arabidopsis thaliana cells with oligogalacturonides (OG) initiates a transient production of reactive oxygen species (ROS), the concentration of which in the medium peaks after about 20 min of treatment. The analysis of OG effects on Ca2+ fluxes shows that OG influence both Ca2+ influx and Ca2+ efflux (measured as 45Ca2+ fluxes) in a complex way. During the first 10 ‐ 15 min, OG stimulate Ca2+ influx and decrease its efflux, while at successive times of treatment, OG cause an increase of Ca2+ efflux and a slight decrease of its influx. Treatment with sub‐μM concentrations of eosin yellow (EY), which selectively inhibits the Ca2+‐ATPase of plasma membrane (PM), completely prevents the OG‐induced increase in Ca2+ efflux. EY also suppresses the transient feature of OG‐induced ROS accumulation, keeping the level of ROS in the medium high. The biochemical analysis of PM purified from OG‐treated cells indicates that treatment with OG for 15 to 45 min induces a significant decrease in Ca2+‐ATPase activation by exogenous calmodulin (CaM), and markedly increases the amount of CaM associated with the PM. During the same time span, OG do not influence the expression of At‐ACA8, the main isoform of PM Ca2+‐ATPase in suspension‐cultured A. thaliana cells, and of CaM genes. Overall, the reported results demonstrate that the PM Ca2+‐ATPase is involved in the response of plant cells to OG and is essential in regulation of the oxidative burst.
Reading, Writing, and Toxics: Children's Health, Academic Performance, and Environmental Justice in Los Angeles
Authors: Pastor Manuel , Sadd James L , Morello-Frosch Rachel
Published: March 2004

A significant body of previous research on environmental justice has demonstrated a disproportionate burden of environmental hazards on low-income and minority residents. In this paper we evaluate spatially indexed data on estimated respiratory and cancer risks associated with exposures to ambient air toxics to show that children of color in the Los Angeles Unified School District suffer potentially disparate health impacts, and that disparities in environmental risks may be associated with diminished school performance—even after controlling for socioeconomic and demographic covariates that generally explain much of the variation in student scores. Remediating environmental health risks in distressed neighborhoods could, therefore, improve both health and human capital.
Policy Framing and Learning the Lessons from the UK's Foot and Mouth Disease Crisis
Authors: Ward Neil , Donaldson Andrew , Lowe Philip
Published: March 2004

The 2001 foot and mouth disease (FMD) epidemic cost over £8 billion and wreaked havoc upon the British countryside. The paper examines the institutional response to the crisis and the subsequent inquiries. Drawing on the ‘garbage-can model’ of organisational choice and ideas of ‘policy framing’, it argues that the institutional response to FMD was tightly focused on agricultural interests. Subsequently, a compartmentalised approach to lesson learning has been partial in its coverage. The result is that important lessons, of a more holistic and integrated nature, have been overlooked despite the replacement of the Ministry of Agriculture with a new Department for the Environment, Food and Rural Affairs.
The Greater London Authority—a Case of Conflict of Cultures? Evidence from the Planning and Environmental Policy Domains
Authors: Rydin Yvonne , Thornley Andy , Scanlon Kath , West Karen
Published: March 2004

The creation of the new Greater London Authority (GLA), with effect from June 2000, has provoked considerable interest in policy and academic circles. It stands as an innovation in London governance, an experiment with the mayoral system in British politics and another example of the New Labour programme of modernisation. For all these reasons, the GLA provides an interesting focus of study. The particular focus of this paper concerns the internal dynamics of the GLA as it strove to establish its policy agenda and modus operandi. We were not so much concerned with policy outcomes in terms of documentation and its orientation, but rather the developing nature of the GLA as an emerging organisation. To this end we analyse the first year of the GLA's operation using the perspective of cultural theory, emphasising the nature of the GLA as a set of overlapping institutions. Developing Hood's and Coyle's applications of cultural theory enables us to comment on the tensions apparent within the GLA in its first year and the prospects for integration across the GLA. It also enables a reassessment of the value of such a cultural theory framework in contexts of organisational evolution.
Treating Farms as Firms? the Evolution of Farm Business Support from Productionist to Entrepreneurial Models
Authors: Phillipson Jeremy , Gorton Matthew , Raley Marian , Moxey Andrew
Published: March 2004

Farming enterprises throughout the European Union have traditionally been treated very differently by the state compared with their nonagricultural counterparts. Agricultural activities have been governed by a separate set of policy objectives, political institutions, and support agencies. However, this agricultural ‘exceptionalism’ is being steadily eroded as markets are partially liberalised, farmers are encouraged to pursue new forms of economic activity, and as government institutions are reformed. Farmers are being encouraged to see themselves as ‘entrepreneurs' to face fundamentally changed markets. There is, therefore, renewed attention to the existing levels of generic business skills within the farming sector and to the nature and effectiveness of business advice and support frameworks in enhancing these skills. The paper investigates the extent to which farmers have experienced different patterns of business support use and perceive themselves as having different generic skills needs in comparison with other rural microbusinesses and considers the attractiveness of different models of delivering business advice to the sector. A review is undertaken of the evolution of rural business support in England together with an analysis of data from a survey of almost 1800 rural microbusinesses in the northeast of England. It is concluded that there are a number of significant challenges facing the adjustment of the farm sector towards a more entrepreneurial model of business development arising from the sector's legacy of separation and exceptionalism within the support framework. In order to help encourage the development of generic business skills an ‘intermediary’ model of business advice is advocated, in which an intermediary agency acts as a bridge between farms and generic business support providers.
Fiscal Decentralization in the Czech and Slovak Republics: A Comparative Study of Moral Hazard
Authors: Bryson Phillip J , Cornia Gary C , Wheeler Gloria E
Published: March 2004

Fiscal decentralization has provided neither the benefits of decentralization nor an independent revenue source for subnational governments in the Czech and Slovak Republics. In Slovakia political conditions early in the transition led to the relative neglect of revenue transfers from the center. This produced financial stress but also encouraged greater fiscal independence for local governments. It also forced them to seek maximal property tax revenues. The Czech Republic made more substantial transfers to local governments, but the development of fiscal autonomy was stifled as transfers reduced the need for own-source local revenues. The Czech real estate tax has remained nominal, as it was under central planning, and its administration is fraught with moral hazard problems. Thus, the property tax never became a vehicle for generating independent funds, but the prospects for the tax are much brighter in the Slovak Republic. This paper offers several views on why the property tax has been more successful in the Slovak Republic.
Closing the Gap: Fiscal Imbalances and Intergovernmental Transfers in Developed Federations
Authors: Bird Richard M , Tarasov Andrey V
Published: March 2004

This paper discusses the concepts of vertical fiscal imbalance (the fiscal gap) and horizontal fiscal imbalance (equalization) and uses several statistics to measure these concepts for the eight developed federal countries: Australia, Austria, Belgium, Canada, Germany, Spain, Switzerland, and the United States. Although the periods covered and the detail provided vary from country to country because of limitations in data availability, the overall coverage in this paper seems more complete and comparable than in previous studies. The paper also outlines briefly the types of intergovernmental fiscal transfers used to deal with fiscal imbalances in the eight countries under consideration. Although this account is necessarily highly condensed, given the complexity of transfer systems in most countries, the frequency with which changes are made, and the difficulty of obtaining complete information, it is nonetheless broadly accurate.
Demand-led Programmes: Challenging Labour-Market Inequalities or Reinforcing them?
Authors: Fletcher Del Roy
Published: March 2004

Demand-led programmes have been a key feature of US welfare-to-work and are being enthusiastically embraced by UK policymakers. The author, drawing upon findings emerging from the evaluation of the New Deal Innovation Fund (round three), discusses the extent to which such interventions are capable of meeting the needs of disadvantaged groups. The key findings are that pilots are primarily benefiting groups closest to the labour market and need to engage community-based organisations if they are to become more inclusive. Yet the risk remains that in using the hiring requirements of employers as a basic standard of job readiness such interventions may legitimate discriminatory behaviour which is a significant cause of the inequalities that some groups face in the labour market.
Evolutionary Economics Perspectives on the Regional—National—International Dimensions of Biotechnology Innovations
Authors: McKelvey Maureen
Published: March 2004

This paper explores how and why relationships between firms, network linkages, and selection environments are related to geographical dimensions, within modern biotechnology at the overlap with pharmaceuticals. Theories from evolutionary economics and innovation studies are used to address questions related to the local–national–international dimensions of innovations. The concept of ‘environmental selection pressures’ is proposed, as one way to make sense of the differing patterns of firm formation, technological specialisation, and innovation. Preliminary evidence about developments in biotechnology-pharmaceuticals in Sweden and Australia is presented, to exemplify the conceptualisation and develop appreciative theorising. The paper concludes with implications for government policy as well as areas for future research.
Knowledge Management in Advanced Technology Industries: An Examination of International Agricultural Biotechnology Clusters
Authors: Ryan Camille D , Phillips Peter W B
Published: March 2004

Innovation—the social process of developing, adapting, and adopting new technologies and products into the economy and society—is being driven by increasingly intensive use of knowledge. Although knowledge is often considered inherently nonrival and nonexcludable, increasing complexity has combined with new private property rights mechanisms to erect barriers to use. One approach to overcoming the challenge of accessing and using knowledge has been for firms and other actors to cluster geographically in a few locations around the world, in order to capture scale and scope economies. This paper offers a theoretical explanation for this agglomeration, examines the extent of clustering in the agricultural biotechnology industry, and investigates one specific cluster—in Saskatoon, Canada—that has sustained success in generating successive innovation. Preliminary results indicate that clusters appear to be prevalent in areas where knowledge is diffuse, complicated, and actively protected. Finally, our results also suggest that regional knowledge management is enhanced through an optimal number of actors operating within the parameters of seven defined cluster-based functions: three primary (science, technology and collective) and four mixed or hybrid activities.
The Molecular Biology Revolution and the Rise of Bioscience Megacentres in North America and Europe
Authors: Cooke Philip
Published: March 2004

This paper focuses on ‘triple helix’ effects in biosciences. Scientific change can have profound socioeconomic effects. The molecular biology revolution tilted pharmaceuticals production away from its fine chemistry path dependence into microbiology and biotechnology. The key to any triple helix effects has thus shifted to universities and spinouts buttressed with burgeoning public funding, leaving ‘big pharma’ increasingly playing the role of licenser and marketer of bought-in therapeutic treatments. Concentration in the healthcare value chain means a few places that have become bioscience ‘mega-centres’ dominate healthcare innovation. Ambitious regions seeking to establish megacentres of their own are causing governments to experiment with ‘regional science policy’ to build up competitiveness.
The US Biotechnology Industry: Industry Dynamics and Policy
Authors: Bagchi-Sen Sharmistha , Smith Helen Lawton , Hall Linda
Published: March 2004

The inseparability of the biotechnology industry and the state is a central theme in the analysis of the location and performance of biotechnology industry in the US and elsewhere. This paper reports on the results of a survey of US biotechnology companies looking particularly at their assessment of needs, barriers, strategies, and government programs. The paper shows that although there is an increasing level of federal and state intervention, there are considerable barriers faced by biotechnology firms, which may or may not be resolved in the near future because of the nature of the business of biotechnology, which involves uncertainties at every stage of innovation and commercialisation.
Prefirm Activities within the Life Science Sector
Authors: Rickne Annika
Published: March 2004

The author examines prefirm activities and firm formation within a subset of the life science sector, namely firms with a core competence in biocompatible materials. In particular, the author scrutinises whether or not prefirm activities are spatially confined, and which mechanisms are involved in such firm-formation processes. Resting the analysis on the empirical example of firms located in Sweden, Ohio, and Massachusetts, the findings indicate that, even though international components are important, the process of firm formation is indeed a geographically delimited activity. In this, experimentation is essential, the direction and volume of the science base may have large impacts, and structural characteristics in the geographical setting are important. The discussion centres on how to spur clustering of firm formation as opposed to mere colocation of new units, where mechanisms include organisational concentration, application interrelatedness, and a spatially confined search process. The firms in the three regions differ: between the firms in Sweden and Massachusetts there are synergies due to geographical proximity and interdependence, knowledge spillovers, and encouragement of innovation within the group of firms, whereas this is not the case in Ohio. Indeed, in Ohio, the mechanisms which are important in creating an innovative cluster do not seem to be as effective.
The Economic Analysis of Industrial Water Demand: A Review
Authors: de Gispert Cristina
Published: March 2004

The author reviews economic studies addressing water use with the aim of identifying key empirical questions that are relevant to the estimation of the demand for water. In particular, the effect of price on demand is specified and the way in which the industrial use of water is characterised is explored; this is markedly different from domestic water use. The main conclusion is that more detailed knowledge is necessary to establish the response of industrial firms to changes in the price of water (or taxes), and thus to guarantee the efficient regulation of water resources.
Beyond Contradictions of the Workfare State? Denmark, Welfare-through-Work, and the Promise of Job Rotation
Authors: Etherington David , Jones Martin
Published: March 2004

The reform of the British welfare state through the Labour Party's welfare-to-work initiative is beginning to generate considerable debate. Research is revealing that, amongst other things, supply-side interventions are not sufficient on their own to build skilled, dynamic, and socially inclusive economies. Although there is an emerging consensus that welfare-to-work is deeply problematic, in UK debates there has been a degree of reluctance to discuss workable alternatives. This paper stimulates debate by focusing on Denmark's labour-market and welfare reforms during the 1990s. As part of a ‘welfare- through-work’ model, fostered on a negotiated and inclusive system of welfare reform, Denmark has followed a strategy that appears to deliver both economic competitiveness and social cohesion, and also raises critical questions around labour market inequalities and the distribution of work. We suggest that the Danish experience can shed light on tensions currently being experienced within Britain. Attention is specifically paid to the origins, development, and promises of job rotation—a radical work-sharing initiative that is being flagged by the European Commission as the good-practice model for ‘sustainable employment’ and ‘lifelong learning’. We argue that important connections exist between the structure of labour-market representation, which is mediated through the social and political forces that can gain access to the state apparatus, and the patterns of policy interventions and their outcomes.
From the Telephone to the Economic Exchange: How Small Businesses Use the Telephone in Their Market Relations
Authors: Mallard Alexandre
Published: March 2004

The fixed telephone plays an important role in the organisation of economic activity. As a low-cost and universal communication tool, it enables actors to pass on information and to have transactions at a distance. However, research on telephone use in the professional sphere has been limited to the particular situation of call centres and has mainly investigated organisational and interactional issues. In this paper I attempt to broaden the scope of analysis and to characterise more generally the inscription of telephony in economic networks. I focus on the population of small businesses and draw on a project concerning 881 firms. The project enables me to combine telephone-traffic data and quantitative survey data concerning the engagement of the telephone in economic activities for these small businesses. A specific methodological standpoint is proposed to explore this empirical material and to characterise the particular nature of telephony in small businesses. The dynamic and asymmetric nature of telephony leads me to question the way in which communication tools can be integrated in an analysis of the spatial inscription of economic activity and networks.
Mathematical Metaphors and Politics of Presence/Absence
Authors: Marques Ivan da Costa
Published: March 2004

Of course the global and the local come together. And so do the universal and the particular. We know that, as well as including the local, whatever the global is it ‘is more than one but less than many’. But what is one? And where can the global one be found, and by whom? One can be studied only in its tensioned relation with the other. The suggestion is that the global and the local, and the large and the small, are effects of modes of ordering; that between them there is no more than ephemeral effects of scale, or effects of ever-changing contingent differences of relative quantities or positions (densities). But, then, how does the global end up being global or the large become large? I will explore this question by focusing on performances of mathematical discourses. How do mathematical discourses intermingle with heterogeneous networks conveying, shaping, and mobilizing intentional but nonsubjective strategies of framing the global as one? And how do heterogeneous networks always locally (partially) escape mathematical capture and constantly overflow often renewed mathematizing framings?
Remembering the Technological Unconscious by Foregrounding Knowledges of Position
Authors: Thrift Nigel
Published: March 2004

In this paper I provide a description and preliminary analysis of the current ‘technological unconscious’. I use this term to signify the basic forms of positioning and juxtapositioning which make up the basic ‘atomic structure’ of contemporary Euro-American life. Because of the potential vastness of the topic, I concentrate on just one form of positioning and juxtapositioning, namely the construction of repetition. The paper is in three parts. The first part provides a capsule history of how a very few templates of position and juxtaposition have become powered up into a capacious and effective background. In the second part of the paper I argue that in recent years the practice of these templates has been changing as a full-blown standardisation of space has taken hold. This standardisation is gradually leading to the crystallisation of a new kind of technological unconscious. In the third part of the paper I argue that the traces of this new kind of unconscious are taking hold in social theory as well, leading to the assumption of a quite different event horizon which can be thought of as a different kind of materiality.
“Those Goody-Goody Estonians”: Toward Rethinking Security in the European Union Candidate States
Authors: Kuus Merje
Published: March 2004

The discursive construction of security in the European Union (EU) candidate states has received little attention. One effect of this gap is to discreetly frame EU applicants as learners or adopters of Western concepts of security. This overlooks the key role of local intellectuals of statecraft in the making of security both in the candidate states and in the Western institutions with which these states integrate. Based on the case of Estonia, this paper exposes the essential obscurity and fluidity of security in Estonia, and highlights the role of Estonian intellectuals in the making and operationalizing of this fluidity. The paper thereby emphasizes the capacity of East European intellectuals of statecraft to influence the problematizations of security in these states themselves and in Western writings about them.
Pacemaking the Modern City: The Urban Politics of Speed and Slowness
Authors: Hubbard Phil , Lilley Keith
Published: March 2004

Many theorists of urban modernity have suggested that modernisation accelerates the pace of life, resulting in faster and more frenetic cities. In this paper we argue that this tells only part of the story, as where there is speed there is also slowness. The mid-20th-century redevelopment of Coventry in the United Kingdom serves to illustrate this: the technocentric conceptions of timespace that became dominant in this period bequeathed a city that sped up for some, but slowed down for others. These differential mobilities indicate the speed politics underpinning the redevelopment of Coventry in the postwar era, with the city centre increasingly moving to the rhythms imposed by a bureaucratic elite. Noting these rhythms were nonetheless subject to interruptions that undermined this spatial and temporal order, we conclude that geographers must be attentive to the uneven production of both space and time to grasp fully the ambivalence of modernity.
Dream Stuff: The Postwar Home and the Australian Housewife, 1940–60
Authors: Lloyd Justine , Johnson Lesley
Published: March 2004

During the postwar period the modern family home assumed a special place in the Australian imaginary. Women achieved a greater public presence in this context, reflected in calls to Australian housewives to think about how their ideal home would look. The ‘new look’ required of the national home was addressed to its occupants, the Australian family, and was articulated through both government policy discourses and the popular media. Planning for and dreaming about modernity became key activities of homemaking. The requirements of women, in particular, to dream and plan for the future family produced the housewife as a modern figure responsible for the planning of a successful future for her family. The modern challenge to make home anew spoke to women's authority on day-to-day living, moving the efficient arrangement of the home and its public exposure firmly into their domain. However, this new, mass-mediated way of looking at domesticity created a contradiction in female domestic subjectivity. On the one hand, both state and market discourses suggested that women could sweep away the elements of traditional, particularly prewar, home designs that bound them to the home. On the other, popular magazines also placed a great deal of emphasis on the look of things and on looking itself, further inscribing women's identity within domestic space. We argue through a case study of the figure of the housewife in Australian home magazines that as a result of this contradiction during this period the identity of ‘housewife’ came to offer a new, reflexive relationship between female selfhood and home. Via the domestication of modernity in terms of gender, previous divisions between the public and private were destabilised. We suggest that the housewife's gaze both towards the home and towards her ‘domestic self’ intensified the problematic of feminity, putting it on the threshold of public and private space, offering a critical, enabling position for an ensuing feminist analysis.
Livestock grazing management and biodiversity conservation in Australian temperate grassy landscapes
Authors: Dorrough J. , Yen A. , Turner V. , Clark S. G. , Crosthwaite J. , Hirth J. R.
Published: March 2004

There is an increasing interest in the development of livestock grazing management strategies that achieve environmental sustainability and maintain or improve the long-term production capacity of commercial grazing systems. In temperate Australia, these strategies are generally focussed on reducing perennial pasture decline, soil loss, acidity, and salinity. An additional challenge facing land managers and researchers is developing grazing strategies that also maintain and enhance local and regional biodiversity. However, few studies have assessed the compatibility of management practices for maintaining long-term productivity and biodiversity conservation. We still have only a very basic understanding of the effects of different grazing strategies and pasture management on biodiversity and this is a major impediment to the development of appropriate and compatible best management practice. We argue that although there is an increasing desire to find management strategies that protect and enhance biodiversity without hindering long-term agricultural production, in many cases this may not be possible. Current knowledge suggests that compatibility is most likely to be achieved using low-input systems in low productivity (fragile) landscapes, whereas in highly productive (robust) landscapes there is less opportunity for integration of productive land-use and biodiversity conservation. There is an urgent need for improved communication and collaboration between agronomic and ecological researchers and research agencies to ensure that future programs consider sustainability in terms of biodiversity as well as pasture and livestock productivity and soil and water health.
The causes of seasonal variation in backfat thickness of pigs in Western Australia
Authors: Trezona M. , Mullan B. P. , D'Antuono M. , Wilson R. H. , Williams I. H.
Published: March 2004

Anecdotal observations suggest that pigs get fatter at certain times of the year. Abattoir data from a major Western Australian genotype were investigated to determine whether there is seasonal variation in P2, and if so, what factors may contribute to this. In the data collected, it was found that pigs were fattest during spring and leanest during autumn. At initial observation, variation in carcass weight (hence liveweight at slaughter) appeared to explain much of the variation in carcass fatness. However, fitting a linear mixed model to the P2 data, adjusted for carcass weight, indicated that there was also a significant effect of season on carcass quality.
Response of lambs fed wheat straw-based diets to supplementation with soybean hulls
Authors: Gomes M. J. , Dias-da-Silva A. A. , Azevedo J. M. T. de , Guedes C. M.
Published: March 2004

A lamb growth and digestion trial and an incubation study were conducted to evaluate the responses to supplementation of a wheat straw (WS)–soybean meal (SB) basal diet with 0, 10, 20, 30, and 40% of soybean hulls (SH) or 29% ground maize and 1% urea (M/U) on a dry matter (DM) basis. DM intake (DMI) increased with SH inclusion up to 30% of the diet, the increase being higher than with the M/U diet. Straw DMI decreased with supplementation, the depression being more severe with M/U than with 30% of SH (405 v. 522 g/day). Digestibilities of diet organic matter (OM) and neutral detergent fibre (NDF) increased, whereas OM digestibility and DM degradation rate (DMc) of WS decreased with SH level. M/U reduced diet NDF digestibility (from 45.9 to 42.3%). OM digestibility and DMc of WS were more severely depressed with M/U than with SH at the similar level of inclusion (from 41.5 to 33.0 v. 39.0% and from 2.63 to 2.16 v. 2.49%/h, respectively). Daily liveweight gain (LWG) and LWG per MJ ME intake (MEI) increased quadratically with SH. Predictions of metabolisable protein (MP) either from the data of the incubation study or from the microbial protein synthesis as assessed by microbial purine excretion, showed that MP may have been in excess of the requirements (11–40%) in diets with 30–40% SH inclusion. Although MEIs of these diets were similar, they gave rise to significantly different LWGs (61.7 v. 84.4 g/day; P < 0.05). By contrast, MEI of the M/U diet was 22% lower than of the diet having 30% SH, but both diets promoted similar LWG. On the whole, the results of this study are interpreted as further evidence that ME of the diets is not a homogeneous entity, the balance of absorbed nutrients being a central issue to predicting the responses of the ruminants.
The influence of fertiliser nitrogen application on development and number of reproductive primordia in field-grown two- and six-rowed barleys
Authors: Arisnabarreta Sebastián , Miralles Daniel J.
Published: March 2004

A field experiment using different 2- and 6-rowed barley cultivars grown at two contrasting nitrogen supply rates (40 and 150 kg N/ha) without water restrictions was carried out to explore how the number of leaf primordia and the rate of leaf emergence interact to modify the duration of different pre-heading phenological phases, and to analyse the dynamics of initiation and mortality of different subcomponents of grain number per unit area, in response to different fertiliser nitrogen regimes.The lower nitrogen supply (40 kg N/ha) delayed heading time as a consequence of higher phyllochron, without any effect on the final number of leaves initiated in the apex. The different fertiliser nitrogen rates only altered the co-ordination between tiller appearance and leaf emergence in two of the 6-rowed cultivars, whereas for the rest of the cultivars, co-ordination between leaf emergence and primary tiller appearance was not altered by fertiliser nitrogen rate. The lower nitrogen supply resulted in less fertile florets per ear due to a reduction in floret primordia survival, without any effect on the maximum number of spikelet primordia initiated in the apex. The higher floret abortion observed in 6-rowed compared with 2-rowed cultivars could be associated with the fact that lateral floret primordia, in those apical and basal positions within the ear in 6-rowed cultivars, are poorly developed with respect to the central spikelets.
Identification of a major QTL for yellow leaf spot resistance in the wheat varieties Brookton and Cranbrook
Authors: Cheong J. , Wallwork H. , Williams K. J.
Published: March 2004

Yellow leaf spot (YLS) or tan spot, caused by Pyrenophora tritici-repentis, is a major foliar disease of wheat. A bioassay was used to identify YLS seedling resistance phenotypes of Krichauff/Brookton and Cranbrook/Halberd doubled-haploid (DH) populations. Bulked-segregant analysis was used to identify amplified fragment length polymorphism (AFLP) markers linked to a YLS resistance locus in the wheat cultivar Brookton. Three AFLPs were linked to YLS resistance and also to each other. One of these AFLPs was mapped to the interval Xbcd351–Xcdo400, which has been assigned to chromosome 5BL. Microsatellite markers in this region were selected from several maps and were genotyped on the Krichauff/Brookton population. Together with the bulked segregant analysis (BSA)-derived AFLPs, the microsatellite markers explained up to 39% of the total phenotypic variation (logarithm of odds ratio, LOD ≥� 7.32), confirming the chromosome 5BL assignment of a Brookton YLS resistance locus, at or near the previously identified Pyrenophora tritici-repentis toxin-insensitivity locus tsn1. The marker–trait linkage was validated in the Cranbrook/Halberd DH population, in which the same microsatellite markers explained up to 60% of the total trait variance for YLS. The markers identified can be used for the selection of the Brookton and Cranbrook YLS seedling resistance locus on chromosome 5B.
Determinants of oil concentration and seed yield in canola and Indian mustard in the lower rainfall areas of Western Australia
Authors: Si P. , Walton G. H.
Published: March 2004

Oil concentration and seed yield of canola (Brassica napus) are usually low and variable when grown in the lower rainfall areas of Western Australia. This paper identifies determinants of oil concentration and seed yield in these areas. Through a series of cultivar × sowing date experiments at 5 lower rainfall locations and one high rainfall location as comparison, we evaluated the impact of sowing date, cultivar, and location on these 2 key agronomic traits. We also examined relationships between oil concentration, seed yield, and post-anthesis duration, post-anthesis temperature, and post-anthesis rainfall with a view to investigate the adaptive requirements of canola for the lower rainfall areas.Cultivars differed in their capacities to produce oil and seed yield. The ranking of cultivars for oil concentration, and seed yield to a lesser extent, remained constant across sowing dates and locations. Both seed yield and oil concentration decreased with delayed sowing. On average, oil concentration was reduced by 1.1 percentage points and seed yield by 309 kg/ha for every 2 weeks delay in sowing. The magnitude of reduction in oil concentration from delayed sowing was far greater in a low rainfall site at Mullewa than in the high rainfall site at Mt Barker.Later sowings shortened post-anthesis duration. With a given sowing date, early flowering cultivars resulted in longer post-anthesis duration. Oil concentration increased by 1.2 percentage points for a 10-day increase in post-anthesis duration. Both oil concentration and seed yield increased with higher post-anthesis rainfall and lower post-anthesis temperature. The rates of increase were 0.7 percentage points for oil and 116 kg/ha for seed yield for every 10-mm increase in post-anthesis rainfall. The rates of reduction were 0.68 percentage points for oil and 289�kg/ha for seed yield for every 1�C increase in post-anthesis temperature. These relationships suggest that a combination of an early date of sowing with an early flowering cultivar would be essential for the production of high yield and high oil canola in the lower rainfall areas. Indian mustard (B. juncea) showed tolerance to high temperature and water deficit, but the low yield potential makes it uneconomical with early sowing. Further improvement in seed yield could be dependent on increased tolerance of canola to high temperature and water deficit during seed growth and development.
Effect of previous crops on crown rot and yield of durum and bread wheat in northern NSW
Authors: Kirkegaard J. A. , Simpfendorfer S. , Holland J. , Bambach R. , Moore K. J. , Rebetzke G. J.
Published: March 2004

The effect of previous crops (oilseed, legume, and cereal) on the incidence and severity of crown rot (Fusarium pseudograminearum, Fp) and yield of wheat was investigated in 3 field studies in northern New South Wales. The experiments were designed to compare the effectiveness of the Brassica break crops canola (Brassica napus L.) and mustard (B. juncea L.) with chickpea (Cicer arietinum L.) on reduction of Fp in subsequent wheat crops. Responses to previous broadleaf and cereal crops were investigated in Fp-tolerant bread wheat (Triticum aestivum L.) and Fp-susceptible durum wheat [Triticum turgidum L. ssp. durum (Dest.)]. In all experiments, broadleaf break crops increased the yield of Fp-susceptible durum wheat compared with durum after cereals (by 0.24–0.89 t/ha). The same response was observed for the Fp-tolerant wheat at 2 of the 3 sites (0.71 and 0.78 t/ha), with a lower yield (0.13 t/ha) after break crops than after cereals at one site during a drought. The yield of the Fp-susceptible durum wheat was generally higher after brassicas than after chickpea (yield advantage 0.27–0.58�t/ha), whereas there was no such difference in the tolerant wheat variety. In most cases, these yield responses to the previous crops were closely related to the severity of Fp infection. Overall yield of susceptible durum wheat was reduced by 1% for each 1% increase in Fp severity at harvest. Residual water and nitrogen (N) did not explain responses to previous crops, although common root rot (Bipolaris sorokiniana) may have contributed to some of the responses at the sites. There was little evidence that the lower disease and higher yield following brassicas compared with chickpea was related to suppression of Fp by biofumigation. More plausible explanations are that residual cereal residues decomposed more rapidly under dense Brassica canopies thus reducing Fp inoculum, that Fp severity was increased following chickpea due to higher soil N status, or that brassicas resulted in soil/residue biology that was less conducive to Fp inoculum survival. Evidence for the latter was provided by consistently higher levels of Trichoderma spp. isolated from wheat following brassicas compared with chickpea or cereals. Irrespective of the mechanisms involved, the results demonstrate that Brassica oilseeds provide an effective break crop for crown rot in northern NSW. Furthermore, brassicas may provide an excellent alternative rotation crop to chickpea for high value durum wheat due to an apparent capacity to more effectively reduce the severity of crown rot infection in subsequent crops.
Water use efficiency and profitability on an irrigated dairy farm innorthern Victoria: a case study
Authors: Armstrong D. P.
Published: March 2004

A study was conducted to look at water use efficiency and profitability on an irrigated dairy farm in northern Victoria. For this case study farm, an economic evaluation was performed for various development options that could result in higher water use efficiency, increased profit, and meet the farm owners' objectives. Water use efficiency was defined as the amount of milk (kg milk fat plus protein) produced from pasture per megalitre of water (irrigation plus effective rainfall).The case study farm data indicated that between 1995–96 and 1998–99 there was no simple, direct association between water use efficiency and profitability. The development options considered included building a new dairy and increasing herd size and either increasing the area of irrigated pasture or intensifying on the existing irrigated area. The likely water use efficiency and economic efficiency were estimated for the various development options. The development budgets suggested that intensifying on the existing irrigated land was the most attractive option, if the predicted improvements in water use efficiency were achieved. This option had an internal rate of return of 64%, broke even after 5 years and was compatible with the objectives of the farm owners.Options that resulted in simultaneous increases in water use efficiency, profitability and labour efficiency appear to be more likely to be adopted than options that focus solely on increasing water use efficiency.
A qualitative approach to improve the effectiveness of products of research findings for users: a case study of the Analytical Irrigation Model
Authors: Keeble B. , Robertson D. , Johnson F.
Published: March 2004

The widespread adoption of research findings by the farming community has traditionally been challenging. Addressing this challenge is a priority as the products of research often aid and underpin the implementation of environmental objectives to ensure that natural resources are used in a sustainable manner. One approach to tackling this challenge is to develop products that are tailored to meet the needs of the users. The Analytical Irrigation Model (AIM, a software tool) was developed with the intention of creating a field-tool to assist farmers to improve their management of border-check irrigation. Using AIM as a case study, this paper demonstrates the value of using a qualitative approach in assessing potential users of research findings, and understanding their requirements. While developing AIM, anecdotal feedback suggested that widespread adoption of the envisaged research products, namely a field-tool, was unlikely. The qualitative study found that service providers to the dairy industry were likely to be the primary users of products of the AIM research. From conducting this qualitative study, service providers identified 4 types of research products that would suit their needs. Incorporating their perspectives enabled the development of products that were more likely to be adopted and consequently increased the effective targeting of the AIM research findings.
Bayesian networks for decision analyses — an application to irrigation system selection
Authors: Robertson D. , Wang Q. J.
Published: March 2004

Farmers are under continual pressure from Government and industry to change farm practices to meet productivity and environmental targets. In response to these pressures, farmers will make decisions to adopt practices that reflect their motivations and priorities. However, where the changes of practice are major, there may be considerable uncertainty associated with the decision-making process. Decision support tools are one method that may assist in reducing the uncertainty associated with decisions about changes in farm practices.Bayesian networks provide a useful tool to assist in the structuring and analysis of decision problems. A Bayesian network is a decision analysis framework, based on Bayesian probability theory, which allows the integration of scientific and experiential knowledge, and the uncertainty associated with this knowledge. The approach involves describing a system in terms of variables and linkages, or relationships between variables, at a level appropriate to the decision making. This is achieved through representing linkages as conditional probability tables and propagating probabilities through the network to give the likelihood of variable outcomes. Therefore, the approach ensures that treatment of risks and uncertainties is an intrinsic part of the decision-making processes. The Bayesian network is dynamic and interactive, and hence if a network previously developed does not fit a user's conceptual understanding of the system, it can be adapted quickly and simply to the cognitive understanding of the user.A case study Bayesian network has been developed for decisions associated with the selection of irrigation systems for irrigated dairy farms in Northern Victoria. This case study demonstrates that the most appropriate irrigation system for a dairy farm is dependent on factors including the amount of irrigation water available and soil types. Analysis of the Bayesian network indicates that the appropriate irrigation system is more sensitive to the income generated from pasture than to the price of water. The Bayesian network can demonstrate the impacts of decisions on the farmer's system and can allow the farmer to evaluate these impacts according to their own priorities and criteria. This information can then be used by the natural resource manager to assess the appropriate level of incentive or penalty required if the farmer is to adopt the preferred option that will also achieve preferable outcomes from a natural resource management perspective.