Term Field Trials Research Articles

Date palm-magnetized biochar for in-situ stabilization of toxic metals in mining-polluted soil: evaluation using single-step extraction methods and phytoavailability

Mining activities provide a pathway for the entry and accumulation of various heavy metals in soil, which ultimately leads to severe environmental pollution. Utilization of various immobilizing agents could restore such contaminated soils. Therefore, in this study, date palm-derived biochars (BCs: produced at 300 °C, 500 °C and 700 °C) and magnetized biochars (MBCs) were employed to stabilize heavy metals (Cd, Pb, Cu and Zn) in mining polluted soil. Metal polluted soil was amended with BCs and MBCs at w/w ratio of 2% and cultivated with wheat (Triticum aestivum L.) in a greenhouse. After harvesting, dry and fresh biomass of plants were recorded. The soil and plant samples were collected, and the concentrations of heavy metals were measured after extracting with water, DTPA (diethylenetriaminepentaacetic acid), EDTA (ethylenediaminetetraacetic acid), and acetic acid. BCs and MBCs resulted in reduced metal availability and uptake, with higher fresh and dry biomass (>36%). MBCs showed maximum decrease (>70%) in uptake and shoot concentration of metals, as these reductions for Cd and Pb reached below the detection limits. Among all single-step extractions, the DTPA-extractable metals showed a significant positive correlation with shoot concentrations of tested metals. Thus, the synthesized BCs and MBCs could effectively be used for stabilizing heavy metals and improve plant productivity in multi-contaminated soils. However, future studies should focus on long term field trials to restore contaminated mining soils using modified biochars.

Heritability of resistance to benedeniosis in Japanese yellowtail (Seriola quinqueradiata) estimated based on long term repeated measurements in field trials

The aim of this study is to assess the feasibility of the genetic improvement of traits related to resistance to the monogenean ectoparasite Benedenia seriolae in Japanese yellowtail Seriola quinqueradiata. Resistance to benedeniosis (incidence of infection by Benedenia parasites) of individual sample fish was evaluated over two generations in long term field trials, as repeated counts of the number of parasites attached to their skin surface. The broodstock was evaluated by repeated counts 12 times, and 13 resistant and 5 susceptive individuals were selected as the parents among 779 candidates. Fourteen families were produced by mating the selected parents and 598 progenies were evaluated by repeated counts 4 times. A total of 7550 phenotypic records for the 1377 individuals were applied to the repeated measures animal model. Estimates of heritability and repeatability for resistance were as h2 = 0.28 ± 0.03 and R = 0.37 ± 0.01, respectively. The differences of resistance among the families were significant and reflected the performances of the selected parents. Whereas severities of benedeniosis varied among the evaluation periods, the individual and family performances of resistance were consistent throughout the study. Both genetically and phenotypically, there were no significant correlations between resistance and body size traits. This report indicates that selective breeding is a promising approach to control benedeniosis in Japanese yellowtail aquaculture.

Long term field trials demonstrate sustainable nutrient supply and uptake in rehabilitated bauxite residue

Establishing a sustainable vegetation cover is one of the most important steps in progressive rehabilitation and final closure of ore-processing residues and tailings facilities. Sustainable rehabilitation partly depends on establishing and maintaining a supply of plant-available nutrients, but few long term field studies demonstrating the success or failure of rehabilitation of degraded land such as mineral processing tailings have been reported. Bauxite-processing residues are a highly sodic, highly alkaline, nutrient-poor by-product generated from alumina extraction, and pose many challenges for successful rehabilitation. This study investigated long term performance of rehabilitation established on bauxite-processing residue storage areas (RSAs) by comparing the nutrient content of the vegetation cover with nutrient concentrations in the underlying residue sand. Five plant species having diverse physiology were selected from rehabilitation varying in age from 1 to 10 years old; these being: Hardenbergia comptoniana – a vigorous growing legume ground cover/creeper), Acacia cochlearis and A. rostellifera - legume shrubs tolerant of sandy, alkaline conditions, Grevillea crithmifolia - a drought-tolerant proteaceous shrub tolerant of alkaline soil, and Spyridium globulosum - a robust, fast-growing shrub, commonly found on alkaline coastal soils. Gypsum incorporation reduced the pH and soluble aluminium levels in residue sand, but also acted as a long-term source of nutrients for the vegetation cover. Legume species contained more nitrogen than non-legumes (2.5% N and 1.5% N, respectively), and decomposition of surface litter increased organic carbon and total and mineral nitrogen contents of the residue sand over time. Nutrient cycling maintained a supply of macro- and micro- nutrients for the vegetation cover, and 10-year old rehabilitation exhibited characteristics similar to an analogue site. This study highlighted the importance of organic matter accumulation, developing a functional microbial community, and a diverse plant species mix on transforming the residue sand characteristics and encouraging nutrient cycling as key mechanisms for establishing a sustainable vegetation cover and functional ecosystem on residue sand embankments.

Effects and Economic Sustainability of Biochar Application on Corn Production in a Mediterranean Climate.

The effects of two types of biochar on corn production in the Mediterranean climate during the growing season were analyzed. The two types of biochar were obtained from pyrolysis of Pinus pinaster. B1 was fully pyrolyzed with 55.90% organic carbon, and B2 was medium pyrolyzed with 23.50% organic carbon. B1 and B2 were supplemented in the soil of 20 plots (1 m2) at a dose of 4 kg/m2. C1 and C2 (10 plots each) served as control plots. The plots were automatically irrigated and fertilizer was not applied. The B1-supplemented plots exhibited a significant 84.58% increase in dry corn production per square meter and a 93.16% increase in corn wet weight (p << 0.001). Corn production was no different between B2-supplemented, C1, and C2 plots (p > 0.01). The weight of cobs from B1-supplemented plots was 62.3%, which was significantly higher than that of cobs from C1 and C2 plots (p < 0.01). The grain weight increased significantly by 23% in B1-supplemented plots (p < 0.01) and there were no differences between B2-supplemented, C1, and C2 plots. At the end of the treatment, the soil of the B1-supplemented plots exhibited increased levels of sulfate, nitrate, magnesium, conductivity, and saturation percentage. Based on these results, the economic sustainability of this application in agriculture was studied at a standard price of €190 per ton of biochar. Amortization of this investment can be achieved in 5.52 years according to this cost. Considering the fertilizer cost savings of 50% and the water cost savings of 25%, the amortization can be achieved in 4.15 years. If the price of biochar could be reduced through the CO2 emission market at €30 per ton of non-emitted CO2, the amortization can be achieved in 2.80 years. Biochar markedly improves corn production in the Mediterranean climate. However, the amortization time must be further reduced, and enhanced production must be guaranteed over the years with long term field trials so that the product is marketable or other high value-added crops must be identified.

Performance of downpipe treatment system for removal of dissolved metals from roof runoff

Abstract Untreated metal roof runoff can contribute elevated zinc and copper to receiving waterways, with associated ecotoxic impacts on the aquatic ecosystem. The majority of the metals in roof runoff are in dissolved form, which can be difficult to remove with conventional stormwater treatment systems. Treatment materials such as limestone and zeolite are capable of removing dissolved metals, but most research to date has only assessed the performance of such materials using synthetic runoff and long contact times. This study assessed the performance of limestone, zeolite and waste mussel shells in a vertical downpipe configuration with short contact time using actual metal roof runoff. Metal removal was compared under flowrates of 1 L/min and 3 L/min, material compaction level (less/more), and material depth (1 m and 0.5 m). A 93%–99% reduction was achieved in dissolved zinc by all treatment materials for all flowrates, compaction levels and depths. Higher variance in dissolved Cu removal rates were observed, with material depth found to have the greatest influence on performance: 84%–99% removal rates were achieved by the three materials at 1 m depth, but for 0.5 m depths, 44%–99%, 34%–92%, and 47%–93% removal were achieved by zeolite, limestone, and waste mussel shells respectively. The mussel shell removal performance was comparable to zeolite and limestone, yet it provides the added benefit of using a waste resource that would otherwise be disposed of to landfill. While this study demonstrates the potential of waste mussel shells for dissolved metal treatment, long term field trials and experimental analysis of the removal mechanisms of waste mussel shells would enable optimization of this treatment technology.

Trade-off between harvest date and lignocellulosic crop choice for advanced biofuel production in the Mediterranean area

Advanced biofuel production requires feedstock with specific composition in terms of quantity and quality. Decisions about the harvest time of perennial energy grasses have important implications for bioconversion process as well as for the life-span of the plant stand. Four-year data from long term-field trials were used to identify the optimal crop-specific harvest date (autumn vs. winter), in relation to advanced biofuel production. Three different perennial energy grasses (i.e., switchgrass, giant reed and miscanthus) were grown at Bologna and Catania (Italy), under northern and southern Mediterranean climate, respectively, adopting a low input management. In addition to the biomass yield and composition, the net energy value (NEV) from agricultural activities, and the energy return on investment (EROI) at the biorefinery gate was also evaluated.At Bologna, switchgrass biomass yield and quality (hemicellulose, cellulose and acid detergent lignin – ADL) were significantly enhanced when harvested in winter. At Catania, giant reed productivity, cellulose and ADL content were unaffected by harvest date, while hemicellulose and ash content decreased in winter. Biomass composition of miscanthus was more stable in Catania than Bologna, however, yield and components resulted significantly higher in Bologna than Catania, due mainly to the more even precipitation distribution throughout the vegetative crop development. The NEV was positive for all energy crops, treatments and locations, with the highest value for miscanthus grown at Bologna. The EROI of lignocellulosic bioethanol ranged from 4.16 for switchgrass in the autumn harvest at Bologna to 4.37 for miscanthus grown at Catania, which showed also the highest theoretical bioethanol production (169.2 kg h−1) at a feeding rate of 300 kg h−1 of raw material. Nonetheless, miscanthus grown at Bologna attained the highest bioethanol yield (12,254 L ha−1).This study proved that investigated perennial grasses are worth to be grown as lignocellulosic feedstock under low input for at least one decade, upon which Mediterranean region biorefineries may gain fourfold the energy invested.

The impact of fungicide treatment and Integrated Pest Management on barley yields: Analysis of a long term field trials database

Abstract This paper assesses potential for Integrated Pest Management (IPM) techniques to reduce the need for fungicide use without negatively impacting yields. The impacts of three disease management practices of relevance to broad acre crops –disease resistance, forecasting disease pressure, and fungicide use – were analysed to determine impact on yield using a long-term field trials database of Scottish spring barley, with information from experiments across the country regarding yield, disease levels, and fungicide treatment. Due to changes in data collection practices, data from 1996 to 2010 were only available at trial level, while data from 2011 to 2014 were available at plot level. For this reason, data from 1996 to 2014 were analysed using regression models, while a subset of farmer relevant varieties was taken from the 2011–2014 data, and analysed using ANOVA, to provide additional information of particular relevance to current farm practice. While fungicide use reduced disease severity in 51.4%of a farmer-relevant subset of trials run 2011–2014, and yields were decreased by 0.62 t/ha on average, this was not statistically significant in 65% of trials. Fungicide use had only a minor impact on profit in these trials, with an average increase of 4.4% for malting and 4.7% for feed varieties, based on fungicide cost and yield difference; potential savings such as reduced machinery costs were not considered, as these may vary widely. Likewise, the1996–2014 database showed an average yield increase of 0.74 t/ha due to fungicide use, across a wide range of years, sites, varieties, and climatic conditions. A regression model was developed to assess key IPM and site factors which influenced the difference between treated and untreated yields across this 18-year period. Disease resistance, season rainfall, and combined disease severity of the three fungal diseases were found to be significant factors in the model. Sowing only highly resistant varieties and, as technology improves, forecasting disease pressure based on anticipated weather would help to reduce and optimise fungicide use.

Winter wheat yields under different soil-climatic conditions in a long-term field trial

The impact of precipitations and air temperatures on winter wheat yields was evaluated in a 34-year long-&lt;br /&gt; term field trial with mineral and organic fertilization established at two experimental sites with different soil-climatic conditions: Ivanovice na Hané with well fertile soils (degraded Chernozem), higher average year temperatures and lower precipitations; Lukavec situated in Bohemian-Moravian highlands with less fertile soils (Cambisol), lower temperatures and higher precipitations. At both sites, a significant positive effect of used fertilizers was noted from the dose of 80 kg N/ha; the best yields were generally obtained at 120 kg N/ha and 160 kg N/ha. The wheat yields at the Ivanovice site were negatively affected by the decrease of precipitations, namely in more fertilized treatments, particularly farmyard manure + mineral nitrogen, from the dose of 80 kg N/ha. A different trend was obtained at the Lukavec site where better winter wheat yields were obtained under lower precipitations. The air temperatures played a positive role at the Lukavec site, but no significant effect of temperature was observed at the Ivanovice site. The less productive areas in highlands can become more interesting for agriculture production with changing climate. However, the soils generally having lower quality and nutrient content can be a limiting factor for obtaining high yields.

The Buckwheat Effect: A Biopesticide for Wireworm?

Growing buckwheat (Fagopyrum esculentum Moench. Caryophyllales: Polygonaceae) in rotation with potato and other vegetable crops has been reported to decrease the density of an invasive wireworm species (Agriotes sputator Linnaeus. Coleoptera: Elateridae) in Nova Scotia, Canada. It was predicted that the negative effects on wireworm populations result from phytochemicals by buckwheat that act as deterrents, anti-feedants, or toxins in the roots or when released into the soil. Choice assays were conducted to test the attractiveness of germinating, branching, and flowering buckwheat, red spring wheat (Triticum aestivum Linnaeus. Poales: Poaceae) and island barley (Hordeum vulgare Linnaeus. Poales: Poaceae) to the larvae. Twenty-one day, no choice feeding assays were conducted to determine change in mass and mortality of A. sputator larvae when fed buckwheat or barley. There was no evidence that the wireworms were deterred by buckwheat and the germinating stage of all three crops was the most attractive based on the 24-h choice assays. After the 21-d no choice feeding assays, no differences between hosts were observed; however, wireworm herbivory significantly reduced the growth of barley but not buckwheat. The findings from the no choice feeding assays suggest that buckwheat may produce anti-feedants, but longer term feeding assays and field trials are required to confirm this possibility.

Long term farming systems affect soils potential for N2O production and reduction processes under denitrifying conditions

N2O is a potent greenhouse gas with an atmospheric lifetime of 114 years which also contributes to ozone layer destruction. Mitigating N2O emissions is especially challenging to the agricultural sector that is responsible for the majority of anthropogenic N2O release. In order to develop effective mitigation strategies, a detailed understanding of drivers for N2O production and reduction in agriculturally managed soils is needed. Denitrification is recognized as one of the most important source processes for N2O emissions from soils. However, the last step in denitrification, the reduction of N2O to N2 is the only known sink for N2O in soil. Although the impact of single parameters on denitrification is quite well documented, there is still a knowledge gap when it comes to the impact of complex farming systems on N2O production and reduction. In this experiment, we incubated soil samples from the DOK long term field trial in Therwil/Switzerland comparing organic (BIOORG) and conventional (CONMIN) farming systems with an a non-fertilized control (NOFERT). Soil samples were incubated under 90% WFPS after fertilization with NH415NO3 equivalent to a moderate fertilization event in the field with 40 kg N ha−1. In order to assess soil's potential for N2O production and reduction, we combined direct measurements of denitrification end products N2O and N2 with molecular analysis of functional denitrifying communities involved in NO2− and N2O reduction on DNA and mRNA levels. In order to monitor N cycling processes under the chosen conditions, stable isotope tracing was employed to quantify nitrification and NO3− consumption rates. Results revealed increased NO3− consumption and greatest potential for N2O emissions in BIOORG as a result of increased soil organic carbon contents. Production of N2 was similar in BIOORG and CONMIN and significantly lower in NOFERT, most likely due to significantly decreased pH inhibiting N2O reduction. This caused the greatest N2O/(N2O + N2) ratios in NOFERT (0.88 ± 0.02) followed by BIOORG (0.79 ± 0.01) and CONMIN (0.68 ± 0.02) (p < 0.001). Lowest N2O/(N2O + N2) ratios in CONMIN were reflected by lowest N2O emissions and coincided with elevated nosZ transcript copies in the beginning of incubation. Although highest N2O emissions in BIOORG were detected, the incubation setup cannot directly be translated to field conditions. Nevertheless, our results emphasize that farming system induced changes on soil geochemical parameters like soil pH and soil organic carbon affect microbial N2O production and reduction processes during denitrification.

Quantum key distribution with hacking countermeasures and long term field trial

Quantum key distribution’s (QKD’s) central and unique claim is information theoretic security. However there is an increasing understanding that the security of a QKD system relies not only on theoretical security proofs, but also on how closely the physical system matches the theoretical models and prevents attacks due to discrepancies. These side channel or hacking attacks exploit physical devices which do not necessarily behave precisely as the theory expects. As such there is a need for QKD systems to be demonstrated to provide security both in the theoretical and physical implementation. We report here a QKD system designed with this goal in mind, providing a more resilient target against possible hacking attacks including Trojan horse, detector blinding, phase randomisation and photon number splitting attacks. The QKD system was installed into a 45 km link of a metropolitan telecom network for a 2.5 month period, during which time the system operated continuously and distributed 1.33 Tbits of secure key data with a stable secure key rate over 200 kbit/s. In addition security is demonstrated against coherent attacks that are more general than the collective class of attacks usually considered.

Influence of Long Term Application of Butachlor on its Dissipation and Harvest Residues in Soil and Rice.

The study delineates the effect of repeated application of butachlor to rice crop from 1997 onwards. Additionally, in 2014 and 2015, dissipation kinetics of butachlor in soil was studied under field and laboratory conditions. The average recovery of butachlor for soil, rice grain and rice straw ranged between 80.3%-93.2% and 82.8%-96.5% with quantification limit of 0.01 and 0.003µgg-1 for HPLC and GC-MS/MS, respectively. The dissipation of butachlor followed first order kinetics and half-life under long term field trials in rice soil varied from 15.2 to 19.29days and 25.94 to 29.79days under field and laboratory conditions, respectively. The residue of butachlor in soil, rice grain and straw samples at harvest over the years was below the quantification limit and no quantifiable amount of metabolites were present in soil at harvest suggestive of its safe application.

SvSv-lines is an effective tool for involvement of the valuable genepool of 1 EBN diploid potato species into breeding

There is a set of wild potato species valuable for breeding, in particular 1 EBN diploid species from Mexico, which is practically not crossable to cultivated potatoes, including Solanum tuberosum dihaploids (2х, 2 EBN), because of strict pre- and postzygotic interspecific reproductive barriers. It is proposed to involve that species germplasm into breeding by using the original SvSv-lines (F2 S. tuberosum dihaploids×S. verrucosum), in which St -alleles have been substituted for Sv from the self-compatible diploid species S. verrucosum not producing stylar S-RNase. It was anticipated that SvSv-lines have the same ability for elimination of prezygotic incompatibility in interspecific hybridization as S. verrucosum due to S-genes of that species in homozygous state. However, their use would help avoid undesirable effects associated with S. verrucosum application (male sterility and reduced tuber formation in hybrids). The aim of the research was estimation of the efficiency of using SvSv-lines, in comparison with S. verrucosum, as a bridge for involvement of the 1 EBN potato species S. bulbocastanum, S. pinnatisectum and S. polyadenium into breeding. It was revealed that SvSv-lines excels S. verrucosum in hybridization efficacy due to abundant and prolonged flowering in later term than S. verrucosum, when flowering of pollinator species occurs. There were significantly less sterile or low fertility genotypes among the hybrids between SvSv-lines and 1 EBN wild species. They had higher ability for tuber formation, and so they were suitable for long term field trials, contrast to hybrids with S. verrucosum. The interspecific hybrids produced were crossed as female parents to S. tuberosum dihaploids.

Prediction of P concentrations in soil leachates: Results from 6 long term field trials on soils with a high P load

We tested if a single soil P capacity test allows for a reliable forecast of P leaching from agricultural soils with a high P load. In regions with intensively managed arable soils, the soil P content has been dramatically increased by overfertilization with significant P leaching losses as a result. As a consequence, in order to control the P losses, P fertilization has been legally restricted. In several EU28 countries, the ammonium lactate extraction method (P-AL) is used as a soil test for P fertilizer advice, but sometimes also to determine the allowed P fertilizer dose to reduce leaching losses. We hypothesize that P-AL as an estimator of soil P capacity should be combined with 0.01M CaCl2 extractable P (P-CaCl2) and/or hot water extractable P (HWP), both estimators of the soil P intensity, to predict P leaching losses in soils with a high P load.Six long term field trials with a high P load (P-AL: 123 to 375mgPkg−1) on silt loam soils with a specific history of organic and inorganic fertilizer application were sampled for soil analysis and to conduct leaching experiments in the laboratory. P concentrations in the leachates served as a proxy for P leaching. Five field trials were used for model calibration and a sixth one for model validation. Two models, either with P-CaCl2 or with HWP as independent variables, have proven to be suited to distinguish soils with low and high risk for P leaching. In the range of P-AL in this study, P-AL proved to be a non-significant factor and was therefore not retained in either of the models. We conclude that for soils with large soil P stocks (high P-AL concentrations), both P-CaCl2 and HWP are suitable to detect the ones with a higher risk of P leaching losses. We suggest a threshold value for P-CaCl2 and HWP to be used in combination with P-AL, to select those soils where further P fertilization restrictions or other measures to reduce P leaching losses are needed most urgently. This threshold value however depends on what is considered as an acceptable P concentration in the leaching water of the tillage layer.

Erratum to: Quantitative PCR shows propagation of Plasmodiophora brassicae in Swedish long term field trials

Erratum to: Quantitative PCR shows propagation of Plasmodiophora brassicae in Swedish long term field trials

Quantitative PCR shows propagation of Plasmodiophora brassicae in Swedish long term field trials

Clubroot (Plasmodiophora brassicae) is a serious soil-borne disease in brassica crops world-wide. We report on a time series of soil samples from Swedish long-term fertility trials started in 1957, 1963 and 1966, which were analyzed for the amount of P. brassicae DNA. The crop rotations included a brassica crop every 4 or 6 years. All experimental sites with a 4-year rotation of oilseed rape, except one with calcium carbonate in the soil profile, showed high (>1000 fg DNA g−1 soil) levels of P. brassicae DNA after 9, 11 and 12 rotations. In contrast, detectable levels (>5 fg DNA g−1 soil) of P. brassicae were found only at one of five sites with a 6-year rotation of spring oilseed rape. In years with high levels of P. brassicae DNA, low yield was reported and a subsequent decline in P. brassicae DNA in soil was observed. Different NPK (nitrogen/phosphorus/potassium) fertiliser regimes resulted in similar P. brassicae DNA levels. The robustness and reliability of the method applied was verified by analyses of soil from individual plots compared with a mixture of plots and by repeated analyses of selected samples, which showed that P. brassicae DNA remained stable during dry storage.

Influence of high density planting system on growth, yield and fruit quality of litchi cv. Rose Scented under humid subtropical region of Uttarakhand

A long term field trial was conducted under humid subtropical tarai conditions of Uttarakhand to study the effect of planting system cum high density planting on tree growth, yield and fruit quality in litchi cv. Rose Scented. Treatments consisted of five planting systems, i.e., square system (control), hedge row system, double hedge row system, paired system and cluster system accommodating 100, 167, 222, 133 and 178 trees/ha, respectively. Plant growth, fruit yield and quality attributes were evaluated for consecutive ten years (2002–2011). In general, all high density planting systems had higher vegetative growth during initial years of fruit production which declined slightly during later part of tree growth. Tree stem girth was found to be higher with smaller plant densities in comparison to high plant densities. Square system (control) of planting was found more promotive of tree growth and individual tree yield as compared to other planting systems. Higher plant densities resulted in reduced fruit drop percentage and higher fruit yield/ha, which was found to be highest in double hedge row system followed by hedge row system. Fruit weight and its quality attributes were non-significantly influenced by different planting systems although, slightly higher fruit weight and T.S.S. was recorded in square system of planting. Finally, observations on tree growth, fruit yield and quality attributes leads to the conclusion that double hedge row system could be the appropriate and economic system of planting for stability and sustainability of fruit yield along with appropriate fruit quality in high density planting of litchi under tarai conditions of Uttarakhand.

The long term use of farmyard manure and compost: Effects on P availability, orthophosphate sorption strength and P leaching

This study was set up to identify the role of dairy farmyard manure and green waste or farm compost used as a source of stable organic matter on soil P availability and P leaching. We sampled two long term field trials (8 and 16 years) on silt loam soil, with continuous amendment of dairy farmyard manure (FYM) and 6 types of organic waste (VFG, BIO), municipal solid waste (MSW), sludge (GWS) or organic farm waste (CMC1, CMC2) composts. Soil P availability was measured as 0.01M CaCl2 extractable P (P-CaCl2) and hot water extractable P (HWP) and fresh subsamples were used to conduct a leaching experiment in unsaturated conditions in the laboratory. Since the P fertilization history was not equal among the treatments, P leaching concentrations (TP) were standardized with the total P content of the soil (Ptot). P-CaCl2, HWP and the P leaching experiment revealed that in long term farmyard manure amended soils, more P becomes available and is susceptible to leaching than in long term VFG, BIO, MSW, CMC1 and CMC2 compost amended soils. We observed a seasonal trend in P-CaCl2 with minimum and maximum at end of winter (February) and mid-summer (July), respectively. Although this trend was independent of the fertilizer type amended on the soil, the P-CaCl2 significantly increased for farmyard manure amended soil, compared to compost amended soil at any time during the sampling period of >1 year. A sorption experiment with radiolabelled orthophosphoric acid (33PO4) revealed that increased soil P availability and P leaching are related to a decrease in orthophosphate sorption in farmyard manure amended soils, which was not observed in compost amended soils. It is concluded that farmyard manure derived P is more available and more prone to leaching compared to compost derived P due to differences in PO4 sorption.

Preliminary examination of chipseals prepared with epoxy-modified bitumen

The properties of model chipseals constructed with epoxy modified bitumen binders (EMB) have been investigated. Changes in the shear modulus, needle penetration and cohesive energy of the EMB were used to monitor changes in the material as it cured at either 35°C or 45°C. Wheel-tracking tests demonstrated that model EMB seals were highly effective at resisting chip embedment into a soft substrate and could be a method of controlling or eliminating chipseal flushing in the field. EMB chipseals demonstrated excellent chip adhesion and resistance to water stripping without the need for additional adhesion agents. The long-term durability of the EMB was investigated via accelerated oxidation to the equivalent of approximately 3.5years in the field and suggests that the EMB will continue to increase in strength as the chipseal ages. Further investigation is needed to properly characterise low temperature behaviour, long term oxidation resistance and long term field trial behaviours.

High speed prototype quantum key distribution system and long term field trial.

Securing information in communication networks is an important challenge in today's world. Quantum Key Distribution (QKD) can provide unique capabilities towards achieving this security, allowing intrusions to be detected and information leakage avoided. We report here a record high bit rate prototype QKD system providing a total of 878 Gbit of secure key data over a 34 day period corresponding to a sustained key rate of around 300 kbit/s. The system was deployed over a standard 45 km link of an installed metropolitan telecommunication fibre network in central Tokyo. The prototype QKD system is compact, robust and automatically stabilised, enabling key distribution during diverse weather conditions. The security analysis includes an efficient protocol, finite key size effects and decoy states, with a quantified key failure probability of ε = 10⁻¹⁰.