Physiological basis of yield variation in response to row spacing and plant density of mungbean grown in subtropical environments

In this study, we investigated the extent and physiological bases of yield variation due to row spacing and plant density configuration in the mungbean Vigna radiata (L.) Wilczek variety “Crystal” grown in different subtropical environments. Field trials were conducted in six production environments; one rain-fed and one irrigated trial each at Biloela and Emerald, and one rain-fed trial each at Hermitage and Kingaroy sites in Queensland, Australia. In each trial, six combinations of spatial arrangement of plants, achieved through two inter-row spacings of 1 m or 0.9 m (wide row), 0.5 m or 0.3 m (narrow row), with three plant densities, 20, 30 and 40 plants/m2, were compared. The narrow row spacing resulted in 22% higher shoot dry matter and 14% more yield compared to the wide rows. The yield advantage of narrow rows ranged from 10% to 36% in the two irrigated and three rain-fed trials. However, yield loss of up to 10% was also recorded from narrow rows at Emerald where the crop suffered severe drought. Neither the effects of plant density, nor the interaction between plant density and row spacing, however, were significant in any trial. The yield advantage of narrow rows was related to 22% more intercepted radiation. In addition, simulations by the Agricultural Production Systems Simulator model, using site-specific agronomy, soil and weather information, suggested that narrow rows had proportionately greater use of soil water through transpiration, compared to evaporation resulting in higher yield per mm of soil water. The long-term simulation of yield probabilities over 123 years for the two row configurations showed that the mungbean crop planted in narrow rows could produce up to 30% higher grain yield compared to wide rows in 95% of the seasons.

Epidemiology and genetic diversity of Tobacco streak virus and related subgroup 1 ilarviruses

A quarter of Australia’s sunflower production is from the central highlands region of Queensland and is currently worth six million dollars ($AUD) annually. From the early 2000s a severe necrosis disorder of unknown aetiology was affecting large areas of sunflower crops in central Queensland, leading to annual losses of up to 20%. Other crops such as mung bean and cotton were also affected. This PhD study was undertaken to determine if the causal agent of the necrosis disorder was of viral origin and, if so, to characterise its genetic diversity, biology and disease cycle, and to develop effective control strategies. The research described in this thesis identified Tobacco streak virus (TSV; genus Ilarvirus, family Bromoviridae) as the causal agent of the previously unidentified necrosis disorder of sunflower in central Queensland. TSV was also the cause of commonly found diseases in a range of other crops in the same region including cotton, chickpea and mung bean. This was the first report from Australia of natural field infections of TSV from these four crops. TSV strains have previously been reported from other regions of Australia in several hosts based on serological and host range studies. In order to determine the relatedness of previously reported TSV strains with TSV from central Queensland, we characterised the genetic diversity of the known TSV strains from Australia. We identified two genetically distinct TSV strains from central Queensland and named them based on their major alternative hosts, TSV-parthenium from Parthenium hysterophorus and TSV-crownbeard from Verbesina encelioides. They share only 81 % total-genome nucleotide sequence identity. In addition to TSV-parthenium and TSV-crownbeard from central Queensland, we also described the complete genomes of two other ilarvirus species. This proved that previously reported TSV strains, TSV-S isolated from strawberry and TSV-Ag from Ageratum houstonianum, were actually the first record of Strawberry necrotic shock virus from Australia, and a new subgroup 1 ilarvirus, Ageratum latent virus. Our results confirmed that the TSV strains found in central Queensland were not related to previously described strains from Australia and may represent new incursions. This is the first report of the genetic diversity within subgroup 1 ilarviruses from Australia. Based on field observations we hypothesised that parthenium and crownbeard were acting as symptomless hosts of TSV-parthenium and TSV-crownbeard, respectively. We developed strain-specific multiplex PCRs for the three RNA segments to accurately characterise the range of naturally infected hosts across central Queensland. Results described in this thesis show compelling evidence that parthenium and crownbeard are the major (symptomless) alternative hosts of TSV-parthenium and TSV-crownbeard. While both TSV strains had wide natural host ranges, the geographical distribution of each strain was closely associated with the respective distribution of their major alternative hosts. Both TSV strains were commonly found across large areas of central Queensland, but we only found strong evidence for the TSV-parthenium strain being associated with major disease outbreaks in nearby crops. The findings from this study demonstrate that both TSV-parthenium and TSV-crownbeard have similar life cycles but some critical differences. We found both TSV strains to be highly seed transmitted from their respective major alternative hosts from naturally infected mother plants and survived in seed for more than 2 years. We conclusively demonstrated that both TSV strains were readily transmitted via virus-infected pollen taken from the major alternative hosts. This transmission was facilitated by the most commonly collected thrips species, Frankliniella schultzei and Microcephalothrips abdominalis. These results illustrate the importance of seed transmission and efficient thrips vector species for the effective survival of these TSV strains in an often harsh environment and enables the rapid development of TSV disease epidemics in surrounding crops. Results from field surveys and inoculation tests indicate that parthenium is a poor host of TSV-crownbeard. By contrast, crownbeard was naturally infected by, and an experimental host of TSV-parthenium. However, this infection combination resulted in non-viable crownbeard seed. These differences appear to be an effective biological barrier that largely restricts these two TSV strains to their respective major alternative hosts. Based on our field observations we hypothesised that there were differences in relative tolerance to TSV infection between different sunflower hybrids and that seasonal variation in disease levels was related to rainfall in the critical early crop stage. Results from our field trials conducted over multiple years conclusively demonstrated significant differences in tolerance to natural infections of TSV-parthenium in a wide range of sunflower hybrids. Glasshouse tests indicate the resistance to TSV-parthenium identified in the sunflower hybrids is also likely to be effective against TSV-crownbeard. We found a significant negative association between TSV disease incidence in sunflowers and accumulated rainfall in the months of March and April with increasing rainfall resulting in reduced levels of disease. Our results indicate that the use of tolerant sunflower germplasm will be a critical strategy to minimise the risk of TSV epidemics in sunflower.

Genetic diversity and epidemiology of Tobacco streak virus and related subgroup 1 Ilarviruses

A quarter of Australia’s sunflower production is from the central highlands region of Queensland and is currently worth six million dollars ($AUD) annually. From the early 2000s a severe necrosis disorder of unknown aetiology was affecting large areas of sunflower crops in central Queensland, leading to annual losses of up to 20%. Other crops such as mung bean and cotton were also affected. This PhD study was undertaken to determine if the causal agent of the necrosis disorder was of viral origin and, if so, to characterise its genetic diversity, biology and disease cycle, and to develop effective control strategies. The research described in this thesis identified Tobacco streak virus (TSV; genus Ilarvirus, family Bromoviridae) as the causal agent of the previously unidentified necrosis disorder of sunflower in central Queensland. TSV was also the cause of commonly found diseases in a range of other crops in the same region including cotton, chickpea and mung bean. This was the first report from Australia of natural field infections of TSV from these four crops. TSV strains have previously been reported from other regions of Australia in several hosts based on serological and host range studies. In order to determine the relatedness of previously reported TSV strains with TSV from central Queensland, we characterised the genetic diversity of the known TSV strains from Australia. We identified two genetically distinct TSV strains from central Queensland and named them based on their major alternative hosts, TSV-parthenium from Parthenium hysterophorus and TSV-crownbeard from Verbesina encelioides. They share only 81 % total-genome nucleotide sequence identity. In addition to TSV-parthenium and TSV-crownbeard from central Queensland, we also described the complete genomes of two other ilarvirus species. This proved that previously reported TSV strains, TSV-S isolated from strawberry and TSV-Ag from Ageratum houstonianum, were actually the first record of Strawberry necrotic shock virus from Australia, and a new subgroup 1 ilarvirus, Ageratum latent virus. Our results confirmed that the TSV strains found in central Queensland were not related to previously described strains from Australia and may represent new incursions. This is the first report of the genetic diversity within subgroup 1 ilarviruses from Australia. Based on field observations we hypothesised that parthenium and crownbeard were acting as symptomless hosts of TSV-parthenium and TSV-crownbeard, respectively. We developed strain-specific multiplex PCRs for the three RNA segments to accurately characterise the range of naturally infected hosts across central Queensland. Results described in this thesis show compelling evidence that parthenium and crownbeard are the major (symptomless) alternative hosts of TSV-parthenium and TSV-crownbeard. While both TSV strains had wide natural host ranges, the geographical distribution of each strain was closely associated with the respective distribution of their major alternative hosts. Both TSV strains were commonly found across large areas of central Queensland, but we only found strong evidence for the TSV-parthenium strain being associated with major disease outbreaks in nearby crops. The findings from this study demonstrate that both TSV-parthenium and TSV-crownbeard have similar life cycles but some critical differences. We found both TSV strains to be highly seed transmitted from their respective major alternative hosts from naturally infected mother plants and survived in seed for more than 2 years. We conclusively demonstrated that both TSV strains were readily transmitted via virus-infected pollen taken from the major alternative hosts. This transmission was facilitated by the most commonly collected thrips species, Frankliniella schultzei and Microcephalothrips abdominalis. These results illustrate the importance of seed transmission and efficient thrips vector species for the effective survival of these TSV strains in an often harsh environment and enables the rapid development of TSV disease epidemics in surrounding crops. Results from field surveys and inoculation tests indicate that parthenium is a poor host of TSV-crownbeard. By contrast, crownbeard was naturally infected by, and an experimental host of TSV-parthenium. However, this infection combination resulted in non-viable crownbeard seed. These differences appear to be an effective biological barrier that largely restricts these two TSV strains to their respective major alternative hosts. Based on our field observations we hypothesised that there were differences in relative tolerance to TSV infection between different sunflower hybrids and that seasonal variation in disease levels was related to rainfall in the critical early crop stage. Results from our field trials conducted over multiple years conclusively demonstrated significant differences in tolerance to natural infections of TSV-parthenium in a wide range of sunflower hybrids. Glasshouse tests indicate the resistance to TSV-parthenium identified in the sunflower hybrids is also likely to be effective against TSV-crownbeard. We found a significant negative association between TSV disease incidence in sunflowers and accumulated rainfall in the months of March and April with increasing rainfall resulting in reduced levels of disease. Our results indicate that the use of tolerant sunflower germplasm will be a critical strategy to minimise the risk of TSV epidemics in sunflower.

Halosulfuron-methyl: A selective herbicide option for the control of the invasive 'Cyperus aromaticus' (Ridley) Mattf. and Kukenth (Navua sedge)

There are currently limited options for the control of the invasive tropical perennial sedge 'Cyperus aromaticus' (Ridley) Mattf. and Kukenth (Navua sedge). The potential for halosulfuron-methyl as a selective herbicide for Navua sedge control in tropical pastures was investigated by undertaking successive field and shade house experiments in North Queensland, Australia. Halosulfuron-methyl and adjuvant rates, and combinations with other herbicides, were examined to identify a herbicide regime that most effectively reduced Navua sedge. Our research indicated that combining halosulfuron- methyl with other herbicides did not improve efficacy for Navua sedge control. We also identified that low rates of halosulfuron-methyl (25 g ha-1 a.i.) were just as effective as higher rates (73 g ha-1 a.i.) at controlling the sedge, and that this control relied on the addition of the adjuvant Bonza at the recommended concentration (1% of the spray volume). Pot trials in the controlled environment of the shade house achieved total mortality under these regimes. Field trials demonstrated more variable results with reductions in Navua sedge ranging between 40-95% at 8-10 weeks after treatment. After this period (16-24 weeks after treatment), regrowth of sedge, either from newly germinated seed, or of small plants protected from initial treatment, indicated sedge populations can rapidly increase to levels similar to pre-application, depending on the location and climatic conditions. Such variable results highlight the need for concerted monitoring of pastures to identify optimal treatment times. Ideally, initial treatment should be done when the sedge is healthy and actively growing, with follow up-treatments applied when new seed heads are produced from regrowth.

An improved simulation model to predict pre-harvest aflatoxin risk in maize

Aflatoxin is a potent carcinogen produced by Aspergillus flavus, which frequently contaminates maize (Zea mays L.) in the field between 40° north and 40° south latitudes. A mechanistic model to predict risk of pre-harvest contamination could assist in management of this very harmful mycotoxin. In this study we describe an aflatoxin risk prediction model which is integrated with the Agricultural Production Systems Simulator (APSIM) modelling framework. The model computes a temperature function for A. flavus growth and aflatoxin production using a set of three cardinal temperatures determined in the laboratory using culture medium and intact grains. These cardinal temperatures were 11.5 °C as base, 32.5 °C as optimum and 42.5 °C as maximum. The model used a low (≤0.2) crop water supply to demand ratio—an index of drought during the grain filling stage to simulate maize crop's susceptibility to A. flavus growth and aflatoxin production. When this low threshold of the index was reached the model converted the temperature function into an aflatoxin risk index (ARI) to represent the risk of aflatoxin contamination. The model was applied to simulate ARI for two commercial maize hybrids, H513 and H614D, grown in five multi-location field trials in Kenya using site specific agronomy, weather and soil parameters. The observed mean aflatoxin contamination in these trials varied from <1 to 7143 ppb. ARI simulated by the model explained 99% of the variation (p ≤ 0.001) in a linear relationship with the mean observed aflatoxin contamination. The strong relationship between ARI and aflatoxin contamination suggests that the model could be applied to map risk prone areas and to monitor in-season risk for genotypes and soils parameterized for APSIM.

An improved simulation model to predict pre-harvest aflatoxin risk in maize

Aflatoxin is a potent carcinogen produced by Aspergillus flavus, which frequently contaminates maize (Zea mays L.) in the field between 40° north and 40° south latitudes. A mechanistic model to predict risk of pre-harvest contamination could assist in management of this very harmful mycotoxin. In this study we describe an aflatoxin risk prediction model which is integrated with the Agricultural Production Systems Simulator (APSIM) modelling framework. The model computes a temperature function for A. flavus growth and aflatoxin production using a set of three cardinal temperatures determined in the laboratory using culture medium and intact grains. These cardinal temperatures were 11.5 °C as base, 32.5 °C as optimum and 42.5 °C as maximum. The model used a low (≤0.2) crop water supply to demand ratio—an index of drought during the grain filling stage to simulate maize crop's susceptibility to A. flavus growth and aflatoxin production. When this low threshold of the index was reached the model converted the temperature function into an aflatoxin risk index (ARI) to represent the risk of aflatoxin contamination. The model was applied to simulate ARI for two commercial maize hybrids, H513 and H614D, grown in five multi-location field trials in Kenya using site specific agronomy, weather and soil parameters. The observed mean aflatoxin contamination in these trials varied from <1 to 7143 ppb. ARI simulated by the model explained 99% of the variation (p ≤ 0.001) in a linear relationship with the mean observed aflatoxin contamination. The strong relationship between ARI and aflatoxin contamination suggests that the model could be applied to map risk prone areas and to monitor in-season risk for genotypes and soils parameterized for APSIM.

Integrating Rapid Phenotyping and Speed Breeding to Improve Stay-Green and Root Adaptation of Wheat in Changing, Water-Limited, Australian Environments

Temperatures have increased and in-crop rainfall decreased over recent decades in many parts of the Australian wheat cropping region. With these trends set to continue or intensify, improving crop adaptation in the face of climate change is particularly urgent in this, already drought-prone, cropping region. Importantly, improved performance under water-limitation must be achieved while retaining yield potential during more favourable seasons. A multi-trait-based approach to improve wheat yield and yield stability in the face of water-limitation and heat has been instigated in northern Australia using novel phenotyping techniques and a nested association mapping (NAM) approach. An innovative laboratory technique allows rapid root trait screening of hundreds of lines. Using soil grown seedlings, the method offers significant advantages over many other lab-based techniques. Another recently developed method allows novel stay-green traits to be quantified objectively for hundreds of genotypes in standard field trial plots. Field trials in multiple locations and seasons allow evaluation of targeted trait values and identification of superior germplasm. Traits, including yield and yield components are measured for hundreds of NAM lines in rain fed environments under various levels of water-limitation. To rapidly generate lines of interest, the University of Queensland “speed breeding” method is being employed, allowing up to 7 plant generations per annum. A NAM population of over 1000 wheat recombinant inbred lines has been progressed to the F5 generation within 18 months. Genotyping the NAM lines with the genome-wide DArTseq molecular marker system provides up to 40,000 markers. They are now being used for association mapping to validate QTL previously identified in bi-parental populations and to identify novel QTL for stay-green and root traits. We believe that combining the latest techniques in physiology, phenotyping, genetics and breeding will increase genetic progress toward improved adaptation to water-limited environments.

Quantification of the inevitable: the influence of soil macrofauna on soil water movement in rehabilitated open-cut mined lands

Recolonisation of soil by macrofauna (especially ants, termites and earthworms) in rehabilitated open-cut mine sites is inevitable and, in terms of habitat restoration and function, typically of great value. In these highly disturbed landscapes, soil invertebrates play a major role in soil development (macropore configuration, nutrient cycling, bioturbation, etc.) and can influence hydrological processes such as infiltration, seepage, runoff generation and soil erosion. Understanding and quantifying these ecosystem processes is important in rehabilitation design, establishment and subsequent management to ensure progress to the desired end goal, especially in waste cover systems designed to prevent water reaching and transporting underlying hazardous waste materials. However, the soil macrofauna is typically overlooked during hydrological modelling, possibly due to uncertainties on the extent of their influence, which can lead to failure of waste cover systems or rehabilitation activities. We propose that scientific experiments under controlled conditions and field trials on post-mining lands are required to quantify (i) macrofauna–soil structure interactions, (ii) functional dynamics of macrofauna taxa,and (iii) their effects on macrofauna and soil development over time. Such knowledge would provide crucial information for soil water models, which would increase confidence in mine waste cover design recommendations and eventually lead to higher likelihood of rehabilitation success of open-cut mining land.

Highly heritable resistance to root-lesion nematode (Pratylenchus thornei) in Australian chickpea germplasm observed using an optimised glasshouse method and multi-environment trial analysis

Pratylenchus thornei is a root-lesion nematode (RLN) of economic significance in the grain growing regions of Australia. Chickpea (Cicer arietinum) is a significant legume crop grown throughout these regions, but previous testing found most cultivars were susceptible to P. thornei. Therefore, improved resistance to P. thornei is an important objective of the Australian chickpea breeding program. A glasshouse method was developed to assess resistance of chickpea lines to P. thornei, which requires relatively low labour and resource input, and hence is suited to routine adoption within a breeding program. Using this method, good differentiation of chickpea cultivars for P. thornei resistance was measured after 12 weeks. Nematode multiplication was higher for all genotypes than the unplanted control, but of the 47 cultivars and breeding lines tested, 17 exhibited partial resistance, allowing less than two fold multiplication. The relative differences in resistance identified using this method were highly heritable (0.69) and were validated against P. thornei data from seven field trials using a multi-environment trial analysis. Genetic correlations for cultivar resistance between the glasshouse and six of the field trials were high (>0.73). These results demonstrate that resistance to P. thornei in chickpea is highly heritable and can be effectively selected in a limited set of environments. The improved resistance found in a number of the newer chickpea cultivars tested shows that some advances have been made in the P. thornei resistance of Australian chickpea cultivars, and that further targeted breeding and selection should provide incremental improvements.

A model for determining the optimal project life span and concession period of BOT projects

The concession agreement is the core feature of BOT projects, with the concession period being the most essential feature in determining the time span of the various rights, obligations and responsibilities of the government and concessionaire. Concession period design is therefore crucial for financial viability and determining the benefit/cost allocation between the host government and the concessionaire. However, while the concession period and project life span are essentially interdependent, most methods to date consider their determination as contiguous events that are determined exogenously. Moreover, these methods seldom consider the, often uncertain, social benefits and costs involved that are critical in defining, pricing and distributing benefits and costs between the various parties and evaluating potentially distributable cash flows. In this paper, we present the results of the first stage of a research project aimed at determining the optimal build-operate-transfer (BOT) project life span and concession period endogenously and interdependently by maximizing the combined benefits of stakeholders. Based on the estimation of the economic and social development involved, a negotiation space of the concession period interval is obtained, with its lower boundary creating the desired financial return for the private investors and its upper boundary ensuring the economic feasibility of the host government as well as the maximized welfare within the project life. The outcome of the new quantitative model is considered as a suitable basis for future field trials prior to implementation. The structure and details of the model are provided in the paper with Hong Kong tunnel project as a case study to demonstrate its detailed application. The basic contributions of the paper to the theory of construction procurement are that the project life span and concession period are determined jointly and the social benefits taken into account in the examination of project financial benefits. In practical terms, the model goes beyond the current practice of linear-process thinking and should enable engineering consultants to provide project information more rationally and accurately to BOT project bidders and increase the government's prospects of successfully entering into a contract with a concessionaire. This is expected to generate more negotiation space for the government and concessionaire in determining the major socioeconomic features of individual BOT contracts when negotiating the concession period. As a result, the use of the model should increase the total benefit to both parties.

'Ladd traps' as a visual trap for male and female Queensland fruit fly, Bactrocera tryoni (Diptera: Tephritidae)

Bactrocera tryoni (Froggatt) is Australia's major horticultural insect pest, yet monitoring females remains logistically difficult. We trialled the ‘Ladd trap’ as a potential female surveillance or monitoring tool. This trap design is used to trap and monitor fruit flies in countries other (e.g. USA) than Australia. The Ladd trap consists of a flat yellow panel (a traditional ‘sticky trap’), with a three dimensional red sphere (= a fruit mimic) attached in the middle. We confirmed, in field-cage trials, that the combination of yellow panel and red sphere was more attractive to B. tryoni than the two components in isolation. In a second set of field-cage trials, we showed that it was the red-yellow contrast, rather than the three dimensional effect, which was responsible for the trap's effectiveness, with B. tryoni equally attracted to a Ladd trap as to a two-dimensional yellow panel with a circular red centre. The sex ratio of catches was approximately even in the field-cage trials. In field trials, we tested the traditional red-sphere Ladd trap against traps for which the sphere was painted blue, black or yellow. The colour of sphere did not significantly influence trap efficiency in these trials, despite the fact the yellow-panel/yellow-sphere presented no colour contrast to the flies. In 6 weeks of field trials, over 1500 flies were caught, almost exactly two-thirds of them being females. Overall, flies were more likely to be caught on the yellow panel than the sphere; but, for the commercial Ladd trap, proportionally more females were caught on the red sphere versus the yellow panel than would be predicted based on relative surface area of each component, a result also seen the field-cage trial. We determined that no modification of the trap was more effective than the commercially available Ladd trap and so consider that product suitable for more extensive field testing as a B. tryoni research and monitoring tool.

Lihaluujauhon soveltuvuus sokerijuurikkaan lannoitteeksi

Lihaluujauho muodostaa maatilojen myytävien kasvi- ja eläinperäisten tuotteiden jälkeen tärkeimmän agroekosysteemeistä poispäin suuntautuvan ravinnevirran. Se sisältää runsaasti pääkasvinravinteita typpeä, fosforia ja kalsiumia (N ~8%, P ~5%, Ca yleensä ~10-15% luuaineksen määrästä riippuen), sekä kaliumia n.1% tai alle. Lihaluujauho on todettu tehokkaaksi lannoitteeksi useilla viljelykasveilla ja sen käyttö on sallittu myös luomuviljelyssä EU-alueella. Lihaluujauhoon ja erityisesti sen rehukäyttöön liittyvistä riskeistä merkittävin on TSE-tautien riski (naudan BSE-, lampaiden ja vuohien scrapie-, sekä ihmisen vCJD-taudit). Rehukäyttöä on monissa maissa rajoitettu 1980-luvulla puhjenneen BSE-kriisin myötä. BSE-taudin leviäminen yhdistettiin tilanteeseen, jossa nautaperäistä lihaluujauhoa käytettiin nautaeläinten rehun ainesosana. Myös lihaluujauhon käytössä turkiseläinrehuna saattaa piillä BSE:n tai muun TSE-taudin riski. Oikein käsitellyn lihaluujauhon lannoitekäyttöön ei kuitenkaan näytä tarkastelemieni tutkimusten perusteella sisältyvän huomattavaa TSEriskiä, jos huolehditaan asianmukaisista varotoimista ja menettelyistä sekä tuotteen valmistusprosessissa, että käytettäessä lannoitetta. Lihaluujauhon lannoitekäytön lisääminen edistäisi ruokajärjestelmämme ravinnekierron sulkemista etenkin fosforin osalta. Lihaluujauho on uusiutuva luonnonvara, jonka lannoitekäytöllä voitaisiin korvata huomattava osa lannoiteaineena kulutettavista fosforipitoisista kiviaineista. Sokerijuurikkaan lannoituskokeissa Varsinais-Suomen Kaarinassa vuosina 2008 ja 2009 lihaluujauhokäsittelyt eivät menestyneet aivan yhtä hyvin satotasovertailussa kuin kontrollikäsittelyiden NPK-väkilannoitteet, mutta laatuominaisuuksiltaan (sokeripitoisuus, amino-N, K, ja Na-pitoisuudet) joiltakin osin kontrollikäsittelyjä paremmin. Kokeissa käytetyt lajikkeet olivat ’Jesper’ vuonna 2008 ja ’Lincoln’ vuonna 2009. Käytetty lihaluujauholannoite oli Honkajoki Oy:n Viljo Yleislannoite 8-4-3, joka sisälsi noin 10% kaliumsulfaatin ja kasviperäisten sivutuotteiden seosta. Viljo-lannoitetta käytettiin sekä yksistään, että yhdistettynä 10-25%:iin väkilannoitetta. Vuoden 2009 Viljo-koejäseniin vielä lisättiin kaliumsulfaattilannoitetta (42% K, 18% S), jotta päästiin annetun kaliumin määrässä päästiin lannoitussuosituksen (60 kg K/ha) tasolle. Pelkkä Viljo-lannoite tuotti merkitsevästi alhaisemmat sadot kuin kontrollikäsittelyt molempina vuosina. Kuitenkin kun Viljolannoitteen ohella käytettiin väkilannoitetta (10-25% kasvin typentarpeesta) päästiin varsin lähelle kontrollikäsittelyiden satotasoja. Myös pelkän LLJ-lannoitteen tuottamat satotasot olivat kuitenkin selvästi paremmat kuin Suomen keskimääräiset juurikassadot. Viljo-käsittelyillä oli selvästi positiivinen vaikutus laatutekijöihin amino-N, K ja Na vuonna 2008, mutta vuonna 2009 näiden pitoisuudet jäivät kontrollikäsittelyjen tasolle. Viljo-käsittelyiden sokeripitoisuudet olivat vuonna 2008 kontrollikäsittelyn luokkaa ja Viljo77%+NK1:n osalta kontrollia merkitsevästi paremmat. Vuoden 2009 sokeripitoisuudet olivat kaikilla koejäsenillä erinomaiset, ja käsittelyiden välillä ei ilmennyt merkitseviä eroja. Kokeiden perusteella kaliumsulfaatilla täydennetty lihaluujauho on hyvin toimiva lannoite sokerijuurikkaalla Suomen olosuhteissa, etenkin yhdistettynä väkilannoitteeseen.

Covariant differentials lead to the design of a novel self-tuning power system stabilizer

Application of differential geometry to study the dynamics of electrical machines by Gabriel Kron evoked only theoretical interest among the power system engineers and was considered hardly suitable for any practical use. Extension of Kron's work led to a physical understanding of the processes governing the small oscillation instability in power system. This in turn has made it possible to design a self-tuning Power System Stabilizer to contain the oscillatory instability over arm extended range of system and operating conditions. This paper briefly recounts the history of this development and touches upon the essential design features of the stabilizer. It presents some results from simulation studies, laboratory experiments and recently conducted field trials at actual plants-all of which help to establish the efficacy of the proposed stabilizer and corroborate the theoretical findings.

Low cost calibrated mechanical noisemaker for hearing screening of neonates in resource constrained settings

Background & objectives: There is a need to develop an affordable and reliable tool for hearing screening of neonates in resource constrained, medically underserved areas of developing nations. This study valuates a strategy of health worker based screening of neonates using a low cost mechanical calibrated noisemaker followed up with parental monitoring of age appropriate auditory milestones for detecting severe-profound hearing impairment in infants by 6 months of age. Methods: A trained health worker under the supervision of a qualified audiologist screened 425 neonates of whom 20 had confirmed severe-profound hearing impairment. Mechanical calibrated noisemakers of 50, 60, 70 and 80 dB (A) were used to elicit the behavioural responses. The parents of screened neonates were instructed to monitor the normal language and auditory milestones till 6 months of age. This strategy was validated against the reference standard consisting of a battery of tests - namely, auditory brain stem response (ABR), otoacoustic emissions (OAE) and behavioural assessment at 2 years of age. Bayesian prevalence weighted measures of screening were calculated. Results: The sensitivity and specificity was high with least false positive referrals for. 70 and 80 dB (A) noisemakers. All the noisemakers had 100 per cent negative predictive value. 70 and 80 dB (A) noisemakers had high positive likelihood ratios of 19 and 34, respectively. The probability differences for pre- and post- test positive was 43 and 58 for 70 and 80 dB (A) noisemakers, respectively. Interpretation & conclusions: In a controlled setting, health workers with primary education can be trained to use a mechanical calibrated noisemaker made of locally available material to reliably screen for severe-profound hearing loss in neonates. The monitoring of auditory responses could be done by informed parents. Multi-centre field trials of this strategy need to be carried out to examine the feasibility of community health care workers using it in resource constrained settings of developing nations to implement an effective national neonatal hearing screening programme.

Fiber Bragg Grating Sensor Package for Submicron Level Displacement Measurements

In this article, the design and development of a Fiber Bragg Grating (FBG) based displacement sensor package for submicron level displacement measurements are presented. A linear shift of 12.12 nm in Bragg wavelength of the FBG sensor is obtained for a displacement of 6 mm with a calibration factor of 0.495 mu m/pm. Field trials have also been conducted by comparing the FBG displacement sensor package against a conventional dial gauge, on a five block masonry prism specimen loaded using three-point bending technique. The responses from both the sensors are in good agreement, up to the failure of the masonry prism. Furthermore, from the real-time displacement data recorded using FBG, it is possible to detect the time at which early creaks generated inside the body of the specimen which then prorogate to the surface to develop visible surface cracks; the respective load from the load cell can be obtained from the inflection (stress release point) in the displacement curve. Thus the developed FBG displacement sensor package can be used to detect failures in structures much earlier and to provide an adequate time to exercise necessary action, thereby avoiding the possible disaster.