It was the purpose of this investigation to present laboratory data concerning the assimilation of inorganic nitrogen by the aquatic actinomycetes. The strains of aquatic actinomycetes under consideration represented a cross section of those currently under culture at North Texas State University.

The influence of effluent addition on denitrification potential in the Thredbo Wetland was observed by comparing an area of the wetland receiving secondary treated effluent with another area receiving no effluent addition. Physico-chemical measurements (Eh, pH and temperature) of the soil were conducted in both sampling areas to characterise the denitrifying environment. Levels of nitrate plus nitrite and ammonium ion in the soil from 0-30cm depth were recorded on a seasonal basis to identify the role of effluent addition and vertical distribution of inorganic nitrogen species in controlling the distribution of denitrification potential in the soil. Denitrification potentials of soils and decaying plant material were evaluated by the acetylene blockage technique. This involved laboratory incubations under optimum conditions of pH, temperature, nitrate concentration, carbon supply, and diffusion. The influence of these physico-chemical factors on denitrification was also investigated. It was found that the effluent addition caused higher denitrification potential in soils and surface decaying plant material by raising soil temperature, lowering Eh, and increasing concentrations of nitrate plus nitrite and ammonium ions. The highest denitrification potential was recorded in the decaying plant material on the soil surface. The highest soil denitrification potential occurred in the 0-6cm depth segment. Carbon supply and pH had no influence on denitrification potential whilst low temperature (5ºC), and restricted diffusion limited denitrification. In terms of tertiary water treatment denitrification in Thredbo Wetland makes a significant-contribution to the removal of nitrogen year-round. However, total nitrogen removal could be increased by increasing the residence time of water in the wetland thereby encouraging greater spatial and temporal interaction between the denitrifiers and the wastewater nitrogen.

<p>The main project Dry preservation of source-separated organic household wastes involves a new technique for treatment of biowaste through drying. Investigations are going on to determine how the dried biowaste best can be used to close the natural circular flow of nutrients. The objective of this degree project is to determine if the dried biowaste can be used as a soil conditioner. By restoring the nutrients in the material to the ground, the natural circular flow is closed. A declaration of contents, including the nutrient levels, C/N ratio, pH and the electrical conductivity of the dried biowaste, was constructed and a germination test was done to make sure that the material did not inhibit sprouting. Further on a method was developed to study the decomposition process, and in particular the nitrogen mineralization of the dried biowaste. This method was then used practically.</p><p>The results of this degree project indicate that the decomposition capacity of the dried biowaste is very good. The germination test showed that the material in a diluted form (up to 50 % dried biowaste) did not inhibit sprouting. The examination of the nitrogen mineralization showed a fast liberalisation of nutrients available to plants, with only a shorter period of nitrogen immobilization. Together these results imply that the dried material could function well as a soil conditioner.</p> / <p>Projektet Torrkonservering av matavfall från hushåll innefattar en helt ny teknik för behandling av bioavfall genom torkning. Undersökningar pågår angående hur det torkade bioavfallet bäst kan användas för att sluta det naturliga kretsloppet. Examensarbetets huvudsyfte var, som ett led i dessa undersökningar, att utreda om det torkade bioavfallet kan användas som ett jordförbättringsmedel. Genom att tillföra bioavfallet till jord så återförs näringen i materialet till marken och kretsloppet sluts. En varudeklaration, med materialets näringshalter, C/N-kvot, pH och elektrisk konduktivitet, togs fram och ett groningstest utfördes för att kontrollera att bioavfallet inte var groningshämmande. Vidare utvecklades en metod för att studera det torkade bioavfallets nedbrytningsegenskaper i form av dess kvävemineralisering. Denna metod användes därefter praktiskt.</p><p>Resultatet av detta examensarbete tyder på att torkat bioavfall har mycket goda nedbrytningsegenskaper. Groningsförsöket visade att materialet i utspädd form (upp till 50 % torkat bioavfall) inte är groningshämmande, och mineraliseringsförsöket visade på en snabb frigörelse av växttillgängligt kväve, och en immobiliseringsperiod på ett par veckor. Tillsammans indikerar dessa resultat att det torkade materialet kan fungera väl som ett jordförbättringsmedel.</p>

The main project Dry preservation of source-separated organic household wastes involves a new technique for treatment of biowaste through drying. Investigations are going on to determine how the dried biowaste best can be used to close the natural circular flow of nutrients. The objective of this degree project is to determine if the dried biowaste can be used as a soil conditioner. By restoring the nutrients in the material to the ground, the natural circular flow is closed. A declaration of contents, including the nutrient levels, C/N ratio, pH and the electrical conductivity of the dried biowaste, was constructed and a germination test was done to make sure that the material did not inhibit sprouting. Further on a method was developed to study the decomposition process, and in particular the nitrogen mineralization of the dried biowaste. This method was then used practically. The results of this degree project indicate that the decomposition capacity of the dried biowaste is very good. The germination test showed that the material in a diluted form (up to 50 % dried biowaste) did not inhibit sprouting. The examination of the nitrogen mineralization showed a fast liberalisation of nutrients available to plants, with only a shorter period of nitrogen immobilization. Together these results imply that the dried material could function well as a soil conditioner. / Projektet Torrkonservering av matavfall från hushåll innefattar en helt ny teknik för behandling av bioavfall genom torkning. Undersökningar pågår angående hur det torkade bioavfallet bäst kan användas för att sluta det naturliga kretsloppet. Examensarbetets huvudsyfte var, som ett led i dessa undersökningar, att utreda om det torkade bioavfallet kan användas som ett jordförbättringsmedel. Genom att tillföra bioavfallet till jord så återförs näringen i materialet till marken och kretsloppet sluts. En varudeklaration, med materialets näringshalter, C/N-kvot, pH och elektrisk konduktivitet, togs fram och ett groningstest utfördes för att kontrollera att bioavfallet inte var groningshämmande. Vidare utvecklades en metod för att studera det torkade bioavfallets nedbrytningsegenskaper i form av dess kvävemineralisering. Denna metod användes därefter praktiskt. Resultatet av detta examensarbete tyder på att torkat bioavfall har mycket goda nedbrytningsegenskaper. Groningsförsöket visade att materialet i utspädd form (upp till 50 % torkat bioavfall) inte är groningshämmande, och mineraliseringsförsöket visade på en snabb frigörelse av växttillgängligt kväve, och en immobiliseringsperiod på ett par veckor. Tillsammans indikerar dessa resultat att det torkade materialet kan fungera väl som ett jordförbättringsmedel.

There are no seeding rates established for organic production of field pea and lentil in Saskatchewan and organic producers must rely upon rates recommended for conventional production of these crops. These seeding rates may not be suitable for organic production as the two systems differ in the use of inputs and in pest management. The objectives of this study were to determine an optimal seeding rate for organic production of field pea and lentil in Saskatchewan considering a number of factors, including yield, weed suppression, soil nitrogen (N) and phosphorus (P) concentrations, soil water storage, colonization of crop roots by arbuscular mycorrhizal fungi (AMF), plant P uptake, and profitability. A field experiment was conducted to determine the optimal seeding rates of field pea and lentil. Field pea seeding rates were 10, 25, 62, 156 and 250 plants m-2 and lentil seeding rates were 15, 38, 94, 235 and 375 plants m-2. Sites were established at Vonda, Vanscoy and Delisle, SK using a randomized complete block designs with summerfallow and green manure treatments included for each crop. Seed yield increased with increasing seeding rate for both crops, up to 1725 kg ha-1 for field pea and 1290 kg ha-1 for lentil. Weed biomass at physiological maturity decreased with increasing seeding rate for both crops. In field pea, weeds were reduced in weight by 68%, while lentil reduced weed biomass by 59% between the lowest and highest seeding rates. <p>Post-harvest soil phosphate-P levels did not change consistently between treatments, indicating that there was no trend in soil P concentration with seeding rate. Post-harvest soil inorganic N, however, was higher for the summerfallow and green manure treatments than for the seeding rate treatments in both crops. Inorganic N was higher at some sites for the highest two seeding rates in field pea. Soil water storage following harvest was not affected by treatment.<p>Colonization of crop roots by AMF increased for lentil with increasing seeding rate, but the same trend was not observed in field pea. A growth chamber experiment to study the rate of colonization of field pea between 10 and 50 d after emergence did not show any differences in AMF colonization between seeding rates. Colonization levels were high (70 to 85%) for both crops in both the field and growth chamber. Arbuscular mycorrhizal fungi colonization and seeding rate had no effect on plant P concentration for either field pea or lentil. Both crops became increasingly profitable as seeding rate increased. Field pea reached a maximum return at 200 plants m-2 and lentil return increased to the highest seeding rate of 375 plants m-2. Organic farmers should increase seeding rates of these crops to increase returns and provide better weed suppression.

There are no seeding rates established for organic production of field pea and lentil in Saskatchewan and organic producers must rely upon rates recommended for conventional production of these crops. These seeding rates may not be suitable for organic production as the two systems differ in the use of inputs and in pest management. The objectives of this study were to determine an optimal seeding rate for organic production of field pea and lentil in Saskatchewan considering a number of factors, including yield, weed suppression, soil nitrogen (N) and phosphorus (P) concentrations, soil water storage, colonization of crop roots by arbuscular mycorrhizal fungi (AMF), plant P uptake, and profitability. A field experiment was conducted to determine the optimal seeding rates of field pea and lentil. Field pea seeding rates were 10, 25, 62, 156 and 250 plants m-2 and lentil seeding rates were 15, 38, 94, 235 and 375 plants m-2. Sites were established at Vonda, Vanscoy and Delisle, SK using a randomized complete block designs with summerfallow and green manure treatments included for each crop. Seed yield increased with increasing seeding rate for both crops, up to 1725 kg ha-1 for field pea and 1290 kg ha-1 for lentil. Weed biomass at physiological maturity decreased with increasing seeding rate for both crops. In field pea, weeds were reduced in weight by 68%, while lentil reduced weed biomass by 59% between the lowest and highest seeding rates. <p>Post-harvest soil phosphate-P levels did not change consistently between treatments, indicating that there was no trend in soil P concentration with seeding rate. Post-harvest soil inorganic N, however, was higher for the summerfallow and green manure treatments than for the seeding rate treatments in both crops. Inorganic N was higher at some sites for the highest two seeding rates in field pea. Soil water storage following harvest was not affected by treatment.<p>Colonization of crop roots by AMF increased for lentil with increasing seeding rate, but the same trend was not observed in field pea. A growth chamber experiment to study the rate of colonization of field pea between 10 and 50 d after emergence did not show any differences in AMF colonization between seeding rates. Colonization levels were high (70 to 85%) for both crops in both the field and growth chamber. Arbuscular mycorrhizal fungi colonization and seeding rate had no effect on plant P concentration for either field pea or lentil. Both crops became increasingly profitable as seeding rate increased. Field pea reached a maximum return at 200 plants m-2 and lentil return increased to the highest seeding rate of 375 plants m-2. Organic farmers should increase seeding rates of these crops to increase returns and provide better weed suppression.

During 1999 ex-situ microcosm experiments were carried out at Dunstaffnage Marine Laboratory, Oban using natural assemblages of microplankton (< 200 m in size) in a series of enrichment experiments using continuous culture techniques to determine q - the yield of chlorophyll from dissolved available inorganic nitrogen (DAH\I), during and after an enrichment event. The experiments lasted between 11 and 14 days and produced a time series of q after an enrichment of either 12 M ammonium or 12 M nitrate. Allother essential nutrients, vitamins and trace metals were added in excess so that only DAIN would limit chlorophyll synthesis. Experiments were carried out during Spring, Summer and Autumn and environmental regimes in the growth room were set-up tomimic ambient conditions at the sampling site for each season. Water samples were collected every 2 days and were analysed for chlorophylls a, b and c, chlorophyll a breakdown products, carotenoids, dissolved inorganic nutrients and particulate nitrogenand carbon. Identification and enumeration of microplankton was also undertaken. During 2 of the experiments nitrogen isotope techniques were used to determine uptake rates for nitrate and ammonium. The results indicated that the microplanktonic response to an enrichment event could be divided into 3 phases: Phase I q - a rapid uptake of DAINand the synthesis of large quantities of pigments; Phase H q - DAIN became limiting and there was a decline in q caused by nutrient limitation and an increase in grazing pressure; Phase II q - after declining q remained fairly stable. Nitrogen tied-up in autotrophicbiomass was transferred to the heterotrophs as grazing pressure and algal death increased accompanied by a calculated rise in dissolved organic nitrogen through degradation processes (assuming mass conservation of nitrogen was occurring in the microcosms),and, presumably, regenerated DAIN. There were seasonal differences in q caused by changing environmental conditions such as light, temperature and background nutrient concentrations. Seasonal changes in the community structure of microplankton collected from the sampling site could also have affected the value of q. During the Summer and Autumn Experiments ammonium enriched microcosms produced lower values of q compared to nitrate enriched microcosms but further investigation is needed to clarify the reasons for this. The method used to estimate chlorophyll or nitrogen had an effect on the value of q. Refined values of q have been produced for use in the screening model used to predict potential eutrophication in the UK.

This study focused on Atmospheric Deposition (AD) loading on Utah Lake. Utah Lake is susceptible to Harmful Algal Blooms (HABs) because of its large surface area to volume ratio, proximity to Great Basin dust sources, and various wind patterns from close mountain ranges that blow AD towards the lake. In this study, we continued the collection and analysis of AD samples that started in 2017 and 2018, while reporting additional 2019 and 2020 data. We constructed a sampler on Utah Lake itself, which allowed us to better estimate how AD loads were distributed over the lake. An interpolation assumption was made in the previous studies that the amount of AD decreases exponentially as it passes onto the lake from the shore. Results from 5 months of Bird Island AD sampling on Utah Lake indicate that this assumption was incorrect. We performed statistical comparison tests on 2 variables: (1) the difference in AD between 2 table heights at the same site and (2) the difference in AD between a filtered sample and an unfiltered sample. We were able to statistically conclude that there was no difference in AD between 1-meter and 2-meter tall sample tables and that filtered AD samples had as much as 3 times lower concentration than unfiltered AD samples. In 2017, the total AD loading was estimated to be, on the high end, approximately 350 tons of total phosphorous (TP) and 460 tons of dissolved inorganic nitrogen (DIN) (Olsen JM, 2018). After making some changes to the interpolation methods, Joshua Reidhead in 2018 estimated AD loads of 153 tons of TP and 505 tons of DIN (Reidhead, 2019). With no changes to the 2018 sampling methods, but using an updated interpolation method, we determined the AD results for Utah Lake in 2019 to be 262 tons of TP and 1052 tons of DIN. After adjustments to the sampling tables, the bucket filters, and incorporating the Bird Island sampler results, we calculated the 2020 AD loading totals to be 133 tons of TP and 482 tons of DIN on the lake.

Atmospheric deposition is a marginally understood source of nutrient loadings to waterbodies. Atmospheric deposition occurs via wet (rain, snow) and dry (gaseous and particulate transport) pathways. Bulk atmospheric deposition is defined as the total deposition from both wet and dry pathways. Utah Lake is a shallow eutrophic freshwater lake located in central Utah, USA. Recent studies have shown atmospheric deposition to be a significant contributor to the nutrient budget of Utah Lake. This study presents the analysis using three different methods of six years' worth of wet atmospheric deposition samples from nine locations around the lake, though these samples do include some contribution from dry deposition. We present and compare nutrient loads and nutrient loading rates for total phosphorus, total in-organic nitrogen, and ortho-phosphorus. We conclude that wet atmospheric deposition contributed between 309 to 529 tons of total phosphorus, 1,166 to 2,078 tons of total nitrogen, and 106 to 201 tons of ortho-phosphorus to the lake during the study period. We extracted loading rates for the calendar year (in tons per year) and winter/summer month (in tons per month) from the data from each of the three methods of analysis. We show that wet atmospheric deposition is a significant pathway in which nutrients are transported to Utah Lake.

El conocimiento de los procesos hidrológicos es esencial para la gestión de los recursos hídricos tanto desde el punto de vista cuantitativo (crecidas o sequías) como desde el punto de vista cualitativo (contaminación). El funcionamiento hidrológico de las cuencas mediterráneas es aún bastante desconocido a pesar de los diferentes estudios realizados desde hace una veintena de años. Los progresos realizados en la identificación y modelización de los procesos hidrológicos corresponden casi en la totalidad a investigaciones realizadas en clima templado-húmedo (Bonell y Balek, 1993; Buttle, 1994). Esta falta de información, fuerza según Bonell (1993) a la "transferencia de resultados", a pesar de la necesidad evidente de desarrollar aproximaciones diferentes, principalmente en el ámbito de la modelización (Pilgrim et al. 1988). Por lo que se refiere a la modelación hidrológica, los estudios disponibles (Durand et al., 1992; Parkin et al., 1996; Piñol et al., 1997 entre otros) muestran serias dificultades para reproducir las primeras crecidas de otoño, después del periodo estival seco. Para estas cuencas parece difícil modelizar correctamente uno o más años hidrológicos completos con un solo juego de parámetros (Piñol et al., 1997, Bernal et al., 2004). El clima mediterráneo está caracterizado por una dinámica estacional muy marcada del régimen de precipitaciones y de la evapotranspiración, que favorece la alternancia durante el año de periodos secos y húmedos. Esto modifica fuertemente el estado hidrológico de la cuenca, de lo que deriva un comportamiento hidrológico complejo y no-lineal (Piñol et al. 1999). La necesidad de comprender el funcionamiento hidrológico de un sistema responde a dos cuestiones importantes: por un lado es el procedimiento más indicado para proporcionar elementos útiles a la gestión integrada de los recursos hídricos y por otro lado es fundamental para la modelación del comportamiento de nutrientes por ejemplo como el nitrato. / Medici ., C. (2010). Progressive development of a hydrologic and inorganic nitrogen conceptual model to improve the understanding of small Mediterranean catchments behaviour [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8428