As the third most important greenhouse gas, nitrous oxide (N2O) is a stable greenhouse gas and also plays a significant role in stratospheric ozone destruction. The primary anthropogenic source of N2O stems from the use of nitrogen in agriculture, with soils being the major contributors. Currently, the annual N2O emissions from this “soil–microbe-plant” system is more than 2.6 Tg (one Tg equals a million metric tons) of N2O-N globally. My doctoral studies aimed to explore innovative strategies for N2O mitigation, in the context of environmental microbiology’s potential contribution to alleviating global warming. The bacterial enzyme nitrous oxide reductase (N2OR), naturally found in some soils, is the only known enzyme capable of catalyzing the final step of the denitrification pathway, conversion of N2O to N2. Therefore, to “scrub” or reduce N2O emissions, bacterial N2OR was heterologously expressed inside the leaves and roots of transgenic plants. Others had previously shown that the functional assembly of the catalytic centres (CuZ) of N2OR is lacking when only nosZ is expressed in other bacterial hosts. There, coexpression of nosZ with nosD, nosF and nosY was found to be necessary for production of the catalytically active holoenzyme. I have generated transgenic tobacco plants expressing the nosZ gene, as well as tobacco plants in which the other four nos genes were coexpressed. More than 100 transgenic tobacco lines, expressing nosZ and nosFLZDY under the control of rolD promoter and d35S promoter, have been analyzed by PCR, RT-PCR and Western blot. The activity of N2OR expressed in transgenic plants, analyzed with the methyl viologen-linked enzyme assay, showed detectable N2O reducing activity. The N2O-reducing patterns observed were similar to that of the positive control purified bacterial N2OR. The data indicated that expressing bacterial N2OR heterologously in plants, without the expression of the accessory Nos proteins, could convert N2O into inert N2. This suggests that atmospheric phytoremediation of N2O by plants harbouring N2OR could be invaluable in efforts to reduce emissions from crop production fields.

This dissertation traces the historical transformation of the Canada-UK commodity chain for wheat-bread as a lens on processes of local and global change in agrofood relations. During the 1990s, the Canadian Wheat Board (Canada’s monopoly wheat seller) and Warburtons, a British bakery, pioneered an innovative identity-preserved sourcing relationship that ties contracted prairie farmers to consumers of premium bread in the UK. Emblematic of the increasing importance of quality claims, traceability, and private standards in the reorganization of agrifood supply chains, I argue that the changes of the 1990s cannot be understood outside of historical legacies giving shape to unique institutions for regulating agrofood relations on the Canadian prairies and in the UK food sector. I trace the rise, fall, and re-invention of the Canada-UK commodity chain across successive food regimes, examining the changing significance of wheat- bread, inter-state relations between Canada, the UK, and the US, and public and private forms of agrofood regulation over time. In particular, I focus on the way in which changing food regime relations transformed the CWB, understood as the nexus of institutions tying prairie farmers into global circuits of accumulation. When in the 1990s, the CWB and Warburtons responded to structural crises in their respective industries by re-inventing the Canada-UK wheat trade, the result was significant organizational and industry change. On the prairies, the CWB has shown how – contrary to expectations -- centralized marketing and quality control may help prairie farmers adapt to the demands of end-users in the emerging ‘economy of qualities’. In the UK, Warburtons has led the ‘premiumisation’ of the bread sector, traditionally defined by consumer taste for cheap bread, over the last 15 years. The significance of the shift towards quality chains in the wheat-bread sector is analyzed in light of conflicts over the proposed introduction of genetically engineered (GE) wheat to the Canadian prairies.

Crop development models are commonly used in research. However, their use as crop management tools for growers is rare. Decision support systems (DSS), which combine crop models with expert systems, are being developed to provide management assistance to growers. Researchers at Oregon State University are in the process of developing a DSS. Research was conducted to develop a computer program to provide current and generated weather data for use by the DSS. The objectives of this research were to obtain a weather station, develop a set of quality control procedures to check data from the station, obtain a weather generator program, and create a weather data manager program to implement the above objectives. A weather station was obtained and was placed near two existing weather stations for ten months. Data from the weather station was compared with the other two stations for values of monthly average maximum temperature, minimum temperature, and daily total solar radiation and monthly total precipitation. The weather station performed well. Only measurements of total daily solar radiation were consistently different from the other stations. Based on a comparison of the weather station with an Eppley pyranometer, a factor was calculated to correct the solar radiation readings. The quality control procedures used on the weather data were adapted from automated procedures given in the literature. When tested, the procedures performed as desired. When used on actual data from the weather station, values that failed the procedures were apparently legitimate values. Options were added to the data manager program that allow the user to quickly decide what to do with failed values. For a weather data generator, WGEN was chosen from the generators presented in the literature. An input parameter file was created for the Corvallis, Oregon area and thirty years of data were generated. Monthly means from this data were compared with thirty-year historical monthly means for Corvallis. Precipitation data from WGEN compared well with the historical data. The generated data for maximum and minimum temperature and daily total solar radiation had great differences from the historical data. It is believed that the input parameters for the Corvallis area suggested by the authors of WGEN are not appropriate. The weather data manager program was written in the C programming language, and occupies approximately 98 kilobytes of disk space, not including the eleven files created directly and indirectly by the program. The main functions of the program are: 1) retrieving data from the weather station and performing quality control procedures on the data (allowing the user to decide what to do with values that failed QC); 2) viewing and editing of files by the user; 3) weather data generation (creating a file of only generated data or appending generated data to the file of current data from the weather station to create a file containing a full year of weather data); and 4) miscellaneous functions (monitoring the weather station, setting the calendar in the station's datalogger, and changing information used by the data manager program). It is hoped that this program will be a significant contribution towards the development of a decision support system. / Graduation date: 1992

This dissertation traces the historical transformation of the Canada-UK commodity chain for wheat-bread as a lens on processes of local and global change in agrofood relations. During the 1990s, the Canadian Wheat Board (Canada’s monopoly wheat seller) and Warburtons, a British bakery, pioneered an innovative identity-preserved sourcing relationship that ties contracted prairie farmers to consumers of premium bread in the UK. Emblematic of the increasing importance of quality claims, traceability, and private standards in the reorganization of agrifood supply chains, I argue that the changes of the 1990s cannot be understood outside of historical legacies giving shape to unique institutions for regulating agrofood relations on the Canadian prairies and in the UK food sector. I trace the rise, fall, and re-invention of the Canada-UK commodity chain across successive food regimes, examining the changing significance of wheat- bread, inter-state relations between Canada, the UK, and the US, and public and private forms of agrofood regulation over time. In particular, I focus on the way in which changing food regime relations transformed the CWB, understood as the nexus of institutions tying prairie farmers into global circuits of accumulation. When in the 1990s, the CWB and Warburtons responded to structural crises in their respective industries by re-inventing the Canada-UK wheat trade, the result was significant organizational and industry change. On the prairies, the CWB has shown how – contrary to expectations -- centralized marketing and quality control may help prairie farmers adapt to the demands of end-users in the emerging ‘economy of qualities’. In the UK, Warburtons has led the ‘premiumisation’ of the bread sector, traditionally defined by consumer taste for cheap bread, over the last 15 years. The significance of the shift towards quality chains in the wheat-bread sector is analyzed in light of conflicts over the proposed introduction of genetically engineered (GE) wheat to the Canadian prairies.

As the third most important greenhouse gas, nitrous oxide (N2O) is a stable greenhouse gas and also plays a significant role in stratospheric ozone destruction. The primary anthropogenic source of N2O stems from the use of nitrogen in agriculture, with soils being the major contributors. Currently, the annual N2O emissions from this “soil–microbe-plant” system is more than 2.6 Tg (one Tg equals a million metric tons) of N2O-N globally. My doctoral studies aimed to explore innovative strategies for N2O mitigation, in the context of environmental microbiology’s potential contribution to alleviating global warming. The bacterial enzyme nitrous oxide reductase (N2OR), naturally found in some soils, is the only known enzyme capable of catalyzing the final step of the denitrification pathway, conversion of N2O to N2. Therefore, to “scrub” or reduce N2O emissions, bacterial N2OR was heterologously expressed inside the leaves and roots of transgenic plants. Others had previously shown that the functional assembly of the catalytic centres (CuZ) of N2OR is lacking when only nosZ is expressed in other bacterial hosts. There, coexpression of nosZ with nosD, nosF and nosY was found to be necessary for production of the catalytically active holoenzyme. I have generated transgenic tobacco plants expressing the nosZ gene, as well as tobacco plants in which the other four nos genes were coexpressed. More than 100 transgenic tobacco lines, expressing nosZ and nosFLZDY under the control of rolD promoter and d35S promoter, have been analyzed by PCR, RT-PCR and Western blot. The activity of N2OR expressed in transgenic plants, analyzed with the methyl viologen-linked enzyme assay, showed detectable N2O reducing activity. The N2O-reducing patterns observed were similar to that of the positive control purified bacterial N2OR. The data indicated that expressing bacterial N2OR heterologously in plants, without the expression of the accessory Nos proteins, could convert N2O into inert N2. This suggests that atmospheric phytoremediation of N2O by plants harbouring N2OR could be invaluable in efforts to reduce emissions from crop production fields.

Dry bean (<i>Phaseolus vulgaris</i>) is currently being introduced for rainfed production in the Dark Brown soil zone in Saskatchewan. Insufficient water is one of the major factors limiting crop production in this soil zone. Ten pinto bean genotypes (Othello, Agate, GH196-2, 6315, 5325, Earliray, Fiesta, ISB82-354, UI 111 and Nodak) were exposed to drought stress in the field to study their rooting pattern under drought stress. Three pinto bean genotypes (Othello, Agate and GH196-2) with an extensive root system in the deeper soil layers and three (Earliray, Fiesta and ISB82-354) with a less extensive root system were exposed to drought stress and nonstress conditions in the growth room and in the field to study the relationship between rooting pattern and seed yield. In addition, three indeterminate pinto bean genotypes (Othello, Nodak and Fiesta) and three determinate genotypes (Agate, Agassiz and Earliray) were exposed to a soil moisture gradient to study the effects of soil moisture level on seed yield and other agronomic traits. Othello, Agate and GH196-2 had an extensive root system in the deeper soil layers, whereas Earliray, Fiesta and ISB82-354 had a less extensive root system in the deeper soil layers. An extensive root system in the deeper soil layers was associated with increased soil moisture depletion at those depths. Shoot dry mass, total root dry mass, mean root length density and root:shoot ratio were the same for the ten pinto bean genotypes. Pinto bean genotypes with an extensive root system (Othello, Agate and GH196-2) in the deeper soil layers had higher seed yield compared to genotypes with a less extensive root system (Earliray, Fiesta and ISB82-354) in the deeper soil layers in the field and in the growth room. Due to insufficient drought stress in the field, the rooting pattern of the six pinto bean genotypes was the same under irrigation and rainfed conditions. In the growth room, pinto bean genotypes with an extensive root system showed a stronger recuperative ability after a severe drought stress compared to genotypes with a less extensive root system. Root traits were positively correlated with seed yield under adequate soil moisture or where drought stress was relieved before maturity. Soil moisture deficit reduced number of pods per plant, plant height, seed weight, seed yield and seed nitrogen concentration of both determinate and indeterminate pinto bean genotypes. Indeterminate pinto bean genotypes had, on average, higher mean seed yield and showed a greater seed yield response to increasing soil moisture availability compared to determinate genotypes. However, the difference in seed yield of the two groups was small under high drought stress, except in the case of one very early maturing determinate genotype.

According to earlier research farmer's crop orientation in developing countries mainly depends on farm size, large-scale farmers prefer cash crop while small-scale farmers prefer subsistence crops. The first aim of this study is to see if this hypothesis can be applied on six households in Babati District in rural Tanzania. The second aim is to investigate if other factors than farm size affect crop portfolio choice and the final aim is to see if those crop portfolio models can be improved. A case-study research design and qualitative interviews are used. The primary data is based on a fieldwork that took place from the 18th of February until the 7th of March 2009 in the study area. From a theoretical perspective the underlying assumptions of the Marcel Fafchamp's model Crop portfolio choice under multivariate risks is discussed in connection to the result of the study. Interviews were made with six households of different farm size. The result of the study indicates that both small-scale and large-scale farmers are using cash crops. The fact that all crops can be used for selling, gives also small-scale farmers in season with higher prices, an opportunity to sell a large share of their crops. It's thereby not possible to state that large-scale farmers devote a larger share of their land for cash crop than small-scale farmers do.

Von 2005 bis 2011 wurden auf unterschiedlichen Versuchsstandorten in Deutschland die Trockenmasseerträge von Sorghumhirsesorten und Maissorten verglichen. Es stellte sich heraus, dass der Anbau von Sorghumhirsen auf allen geprüften Standorten mit Erfolg möglich ist und eine Alternative zum Mais im Energiefruchtfolgesystem darstellt. Die Sorghum bicolor-Sorten erreichen ein höheres Ertragspotenzial als die Hybridsorten (Sorghum bicolor x sudanense). Die Hybridsorten zeichnen sich durch eine schnellere Abreife aus und erreichen silierfähige Trockensubstanzgehalte. Verglichen mit Mais erzielen die Sorten der Sorghumart Sorghum bicolor insbesondere auf den D-Süd-Standorten gleiche oder bessere Erträge.

Ausgewertet wurde der Anbau von Sorghumhirsen auf Versuchsfeldern unterschiedlicher bodenklimatischer Bedingungen. Dabei variierten Versuchsparameter wie Bodenbearbeitung, Aussaattermin, Saatstärke, Reihenweite, Saattiefe und Unkrautregulierung. Für Sorghum bicolor wurde eine optimale Saatstärke von 25 und für die Sudangräser von 40 Körnern/m² ermittelt. Die Reihenweiten sind von untergeordneter Bedeutung, sodass die übliche Drillweite im Betrieb nicht verändert werden muss. Die Versuche zeigen, dass Sorghum sowohl als Drill-, Einzelkorndrillsaat als auch im Mulchsaatverfahren ausgebracht werden kann. Heft 24/2012 der Schriftenreihe des Landesamtes für Umwelt, Landwirtschaft und Geologie mit dem Titel „Ergebnisse mehrjähriger Sortenversuche Sorghumhirsen“ bilanziert die Trockenmasseerträge von Sorghumhirsesorten im Vergleich zu Mais.

Diss. (sammanfattning) Skara : Sveriges lantbruksuniv., 2009. / Härtill 4 uppsatser.