Semi-natural upland plant communities in the U.K. characterised by calcifugous grasslands and montane dwarf shrub communities, with low N requirements, are thought to be particularly vulnerable to the effects of N pollution. N deposition can be enhanced at high altitude sites <I>via</I> cloud droplet deposition and the seeder-feeder effect and the consequences of this for upland vegetation were investigated. Sampling of a range of upland plant species on altitudinal transacts at sites of known N deposition showed that the foliar N concentration increased with altitude and appeared to reflect the enhancement of N deposition with altitude at these sites. Transplant experiments with <I>Nardus stricta</I> in pots and turves showed that although this species reflected N deposition to some extent, the relationship was modified by temperature. This should be taken into account in any attempt to biomonitor N deposition using higher plants. A two year experiment in which upland plant species were misted with N at a rate typical of more polluted sites in the U.K. (60 kg N ha^-1 yr^-1) produced increased root and shoot tissue N concentrations in all species and differential effects on growth and nutrient allocation, and flowering. The dwarf shrubs <I>Vaccinium vitis-idaea</I> and <I>Erica cinerea</I> showed a decrease in root:shoot ratio as a consequence of increased shoot growth, as did the sedge <I>Eriophorum vaginatum</I>, but in the grass <I>Nardus stricta</I> both root and shoot growth were stimulated with the result that there was no change in root:shoot ratio. The magnitude of the response of foliar N concentration to N deposition was species specific and greatest in slow growing species, such as dwarf shrubs, which showed preferential allocation of N to the shoots.

Nonpoint source nitrogen runoff from agriculture is a significant contributor to eutrophication in the Chesapeake Bay. The state of Virginia has developed several market and incentive-based water quality credit trading programs to meet federal water quality objectives. In theory, these programs offer a mechanism to achieve environmental goals at least cost. However, in practice these programs face ongoing challenges arising from limited participation by farmers who supply water quality credits and, as a result, often fail to achieve cost efficiency. We build a flexible, accessible, and modular bioeconomic modeling system as a proof-of-concept to evaluate economic-environmental tradeoffs farmers face in an effort to support program participation and achieve environmental goals. We couple a biophysical nitrogen mass-balance model with an agricultural production model and apply the tool to study diverse agroforestry practices. We evaluate the relative efficiency of these practices by empirically estimating a production possibility frontier. We then use our bioeconomic modeling results to define the minimum willingness to accept of farmers, in terms of water quality credit prices, to adopt agroforestry practices that deliver water quality improvements. We extend our model results to estimate water quality credit premiums to compensate risk-averse farmers for undertaking production practices subject to relatively volatile prices in niche fruit markets. We demonstrate that the model generally simulates real-world credit prices, and highlight potential improvements in design for Virginia's trading program. In particular, quality credit trading programs could be more effective and efficient if credits awards reflect heterogeneity in the environmental benefits associated with nuanced land-use alternatives. Our modeling tool offers a framework to support incentive programs that are both economically sound and biophysically grounded. / Master of Science / High levels of nitrogen in the Chesapeake Bay have become an environmental concern for regulatory agencies. A significant portion of nitrogen pollution in the Chesapeake Bay comes from agricultural activities in the Chesapeake Bay watershed. Agricultural nitrogen pollution is not directly regulated at the federal level, so some states have adopted market-based mechanisms to curb emissions. However, some of these programs are seeing less farmer participation than expected. We suggest that part of the low participation rates may be due to program design, and the impact risk plays in farmer decision-making. In an effort to better understand participation in the programs, we develop a method to model these programs’ environmental and economic outcomes. Our method couples a mechanistic model of nitrogen pollution with an agricultural production model and evaluates tradeoffs between economic and environmental values. We find that the modeling method shows promise as a tool for policymakers, researchers, and farmers interested in pollution abatement programs. As a proof-of-concept, we apply the model to a Virginia market-based program and test our low-participation hypotheses. We find that the programs may be more effective if they recognize a greater diversity of farming practices. Our modeling tool offers a framework to support pollution abatement programs that are both economically feasible and environmentally effective.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.

This study offers two cost analyses to inform public policy decisions on the use of land and water resources. The first presents some public service costs associated with different spatial forms of land development. The second cost analysis presents costs associated with three different policy options for meeting water quality goals in Long Island Sound. The objective the first analysis is to determine the cost to local governments of providing water distribution and wastewater collection services to alternative spatial forms of residential development. Components of spatial form are explicitly defined in terms of lot size, distance and tract dispersion. An engineering cost model is used to determine the water and sewer costs to three sets of hypothetical land settlement scenarios. Each set shows the effect of one component of spatial form on cost. The results show that smaller lots, shorter distances between existing centers and less tract dispersion reduce public water and sewer costs. Lot size is found to have the most pronounced effect on water and sewer cost. Some policy options for reducing the public service costs associated with development are considered. The objective of the second cost analysis is to analyze the cost implications of a nitrogen allowance trading system for wastewater treatment plants in Connecticut. Effluent allowance trading involves the transfer of pollution control responsibility between pollution sources. Effluent allowances are the right to discharge a given quantity of waste into the environment over a given time period. Allowance trading has been proposed as a way of reducing pollution control costs, encouraging innovative pollution prevention techniques and more quickly achieving water quality goals. Long Island Sound, a major estuary in the northeastern United States, experiences chronically low dissolved oxygen levels. Excessive nitrogen loads from anthropogenic activities in the Sound watershed have been identified as the cause of the oxygen problem. The state of Connecticut is examining the possibility of introducing an effluent allowance trading system in order to reduce the cost of achieving required reductions in nitrogen discharge. A linear programming model is used to predict trading outcomes and allowance prices. The total cost of achieving a nitrogen load cap is calculated under three administrative approaches. The first approach is a uniform reduction requirement where all plants are required to reduce discharge by the same proportion. The second approach is an administrative reallocation of waste load where a regulatory agency assigns control responsibility based on the agency's understanding of relative costs. The third approach is a flexible effluent allowance trading system. The results will show that a trading program offers cost savings over traditional regulatory approaches, demonstrate the potential for further cost savings from pollution prevention activities and estimate the cost savings that would result from including nonpoint sources in the overall nitrogen reduction strategy. / Master of Science

Η ρύπανση από τα χημικά λιπάσματα είναι έντονη στα ελληνικά εδάφη (ιδιαίτερα από τα νιτρικά άλατα) και επομένως είναι κρίσιμη η μείωση των εισροών αγροχημικών στο περιβάλλον. Η μείωση της λίπανσης αυξάνει την συγκέντρωση αντιοξειδωτικών ουσιών στους φυτικούς ιστούς. Πολλές επιστημονικές μελέτες μέχρι σήμερα συσχετίζουν την διατροφή με φυτικά προϊόντα υψηλής διατροφικής αξίας που περιέχουν φαινολικές-αντιοξειδωτικές ουσίες με την πρόληψη καρδιαγγειακών παθήσεων, πολλών μορφών καρκίνου αλλά και την γήρανση. Έτσι η έρευνα αυτή είχε διπλό στόχο: τη μείωση της ρύπανσης του περιβάλλοντος μέσω της μείωσης των λιπασμάτων που χορηγούνται στις καλλιέργειες, και την παραγωγή φυτικών προϊόντων υψηλής βιολογικής και διατροφικής αξίας, αφού θα παρέχουν μεγαλύτερες ποσότητες αντιοξειδωτικών ουσιών στον ανθρώπινο οργανισμό. Επίσης θα πρέπει να αναφερθεί ότι η μείωση των ποσοτήτων των λιπασμάτων που θα απαιτούνται για την καλλιέργεια των φυτών θα επιφέρει και οικονομικό όφελος προς τους καλλιεργητές και τους καταναλωτές, αφού θα μειωθεί το κόστος παραγωγής των φυτικών προϊόντων. Για το σκοπό αυτό μελετήθηκε για πρώτη φορά η επίδραση της μεταβολής της συγκέντρωσης των χορηγούμενων νιτρικών ιόντων μέσω του θρεπτικού διαλύματος υδροπονικής καλλιέργειας στο ρυθμό παραγωγής πολυφαινολικών ενώσεων σε λαχανικά ευρείας κατανάλωσης (παντζάρι και μαρούλι) και διαπιστώθηκε ότι η μεγιστοποίηση της παραγωγής των φυσικών αντιοξειδωτικών παραγόντων είναι δυνατή μέσω του ελέγχου της αζωτούχου θρέψης. Παράλληλα, διαπιστώθηκε και ποσοτικοποιήθηκε η ύπαρξη ενός κρίσιμου σημείου στη συγκέντρωση του χορηγούμενου αζώτου που ενεργοποιεί τον δευτερογενή μεταβολισμό των καλλιεργούμενων φυτών παντζαριού και μαρουλιού, αυξάνοντας σημαντικά το ρυθμό παραγωγής των ιδιαίτερα ευεργετικών για την υγεία φυτοχημικών ενώσεων όπως φαινολικών και μπετακυανινών. Η αύξηση όχι μόνο της περιεκτικότητας αλλά και της ενεργότητας των αντιοξειδωτικών παραγόντων επιβεβαιώθηκε με τη χρήση προηγμένων μεθόδων προσδιορισμού όπως το EPR. Τέλος προσδιορίστηκαν και ποσοτικοποιήθηκαν με σύγχρονη μέθοδο φασματομετρίας μαζών (LC-MS/MS) στα διαφορετικά μέρη των φυτών παντζαριού και στα φύλλα του μαρουλιού συνολικά επτά διαφορετικές πολυφαινολικές ενώσεις. / The pollution from chemical fertilizers is pronounced in Greek soils (particularly nitrates) and is therefore critical to reduce inputs of agrochemicals in the environment. The decrease of fertilization increases the concentration of antioxidants in plant tissues. Many scientific studies to date relate the diet with plant products of high nutritional value containing phenolic-antioxidants with the prevention of cardiovascular disease, number of cancers and aging. So the aims of the present research are: to reduce environmental pollution by reducing fertilizer applied to crops, and the production of crops with high biological and nutritional value, providing greater amounts of antioxidants in the human body. It should also be noted that the decrease in the quantities of fertilizer that will be required for the cultivation of plants will also lead to economic benefits to farmers and consumers, as it will reduce the cost of production of plant products. For this purpose the effect of varying concentration of nitrate granted via hydroponic nutrient solution, in the production rate of polyphenolic compounds in vegetables (lettuce and beetroot) was studied. It was found that maximizing the production of natural antioxidants is possible through the control of nitrogen nutrition. Also, it was ascertained that a critical point in the concentration of the administered nitrogen exists below which the secondary metabolism of the studied crops i.e. beetroot and lettuce is activated, significantly increasing the rate of production of the highly beneficial for the health compounds such as phenolic phytochemicals and betacyanins. The augmentation of the activity of antioxidants was confirmed by using advanced methods such as EPR. Finally seven different polyphenolic compounds were identified and quantified by the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS), in different plant parts of beetroot and lettuce leaves.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20005号 / 農博第2189号 / 新制||農||1045(附属図書館) / 学位論文||H28||N5014(農学部図書室) / 33101 / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 藤原 正幸, 教授 村上 章, 准教授 宇波 耕一 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Improving the efficiency and performance of vehicle propulsion systems has always been desirable, and with increasing environmental awareness this has become increasingly topical. A particularly strong focus today is at fossil-free alternatives, and there is a strong trend for electrification. Hybrid powertrains of different types can bring benefits in certain aspects, and there is a lot of research and development involved in the making of a new powertrain. In this thesis, a complete powertrain for a fuel cell hybrid electric vehicle is modeled, with the intention of contributing to this trend. The model can be used to investigate design choices and their impact on energy consumption. A component-based library is developed, with the purpose of being easy to implement for different configurations. The results show that it is possible to assemble and simulate a complete hybrid drivetrain, using the modeled components, while not being very computationally heavy. The developed models correspond well with reality while being modular and easy to implement.