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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Balanced nutrition and crop production practices for the study of grain sorghum nutrient partitioning and closing yield gaps

McHenry, Bailey Marie January 1900 (has links)
Master of Science / Agronomy / Ignacio Ciampitti / P. V. Vara Prasad / Mid-west grain sorghum (Sorghum bicolor (L.) Moench) producers are currently obtaining much lower than attainable yields across varying environments, therefore, closing yield gaps will be important. Yield gaps are the difference between maximum economic attainable yield and current on-farm yields. Maximum economic yield can be achieved through the optimization of utilizing the best genotypes and management practices for the specific site-environment (soil-weather) combination. This research project examines several management factors in order to quantify complex farming interactions for maximizing sorghum yields and studying nutrient partitioning. The factors that were tested include narrow row-spacing (37.5 cm) vs. standard wide row-spacing (76 cm), high (197,600 seeds haˉ¹) and low (98,800 seeds haˉ¹) seeding rates, balanced nutrient management practices including applications of NPKS and micronutrients (Fe and Zn), crop protection with fungicide and insecticide, the use of a plant growth regulator, and the use of precision Ag technology (GreenSeeker for N application). This project was implemented at four sites in Kansas during 2014 (Rossville, Scandia, Ottawa, and Hutchinson) and 2015 (Topeka, Scandia, Ottawa, Ashland Bottoms) growing seasons. Results from both years indicate that irrigation helped to minimize yield variability and boost yield potential across all treatments, though other factors affected the final yield. In 2014, the greatest significant yield difference under irrigation in Rossville, KS (1.32 Mg haˉ¹) was documented between the ‘low-input’ versus the ‘high-input’ treatments. The treatment difference in grain sorghum yields in 2014 was not statistically significant. In 2014, the Ottawa site experienced drought-stress during reproductive stages of plant development, which resulted in low yields and was not influenced by the cropping system approach. In 2015 the treatments were significant, and in Ottawa, narrow row spacing at a lower seeding rate maximized yield for this generally low-yielding environment (<6 Mg haˉ¹) (treatment two at 6.26 vs. treatment ten at 4.89 Mg haˉ¹). Across several sites, including Rossville, Hutchinson, Scandia, Topeka, and Ashland, a similar trend of narrow row spacing promoting greater yields has been documented. Additionally, when water was not limiting sorghum yields (i.e., under irrigation), a balanced nutrient application and optimization of production practices did increase grain sorghum yields (‘high-input’ vs. ‘low-input’; the greatest difference was seen in 2014 in Rossville, 1.2 Mg haˉ¹, and in 2015 in Ashland, 1.98 Mg haˉ¹). In the evaluation of nutrient uptake and partitioning in different plant fractions, there was variability across all site-years which did not always follow the same patterns as the yield, however, the low-input treatment was shown to have significantly lower nutrient uptakes across all the nutrients evaluated (N, P, K, S, Fe, Zn) and across most fractions and sampling times. The objectives of this project were to identify management factors that contributed to high sorghum yields in diverse environments, and to investigate nutrient uptake and partitioning under different environments and crop production practices.
102

Small waterbody fisheries and the potential for community-led enhancement : case studies in Lao PDR

Garaway, Caroline Jane January 1999 (has links)
Based on case studies in Lao PDR, this research investigates the importance of small waterbody fisheries to rural households, the impact of enhancement initiatives on resources and resource users, and the opportunities and constraints of communityled enhancement. Detailed biological, socio-economic, and institutional data on small water body fisheries were collected and analysed in an integrated framework. Small waterbody fisheries contributed substantially to rural livelihoods, with average household catches of 66 kg/year, equivalent in value to approximately half the household rice production (the major crop grown in the region). Poorer households caught and sold more fish than other socio-economic groups. Active management of small waterbody fisheries by stocking and the regulation of fishing had significant impacts on fish stocks, yields, and the type, magnitude and distribution of benefits to villagers. Stocked fisheries managed by and for the village showed higher standing stocks and returns to fishing effort, and thus generated substantial efficiency benefits even though yields were not significantly higher than in unmanaged fisheries. Benefits were in the form of income to the community, partially passed on to households, (equally between socio-economic groups), through reduced financial contributions to the village. Institutional analysis suggests that locally adapted rules, ownership rights, low cost monitoring and enforcement, and information about benefits are key factors in promoting and sustaining community enhancement efforts, as well as the presence of individuals with substantial leadership skills. Results suggest that communities can and do successfully set up and maintain enhancement initiatives and that enhancement of small water body fisheries can generate substantial benefits. However these will only be sustained if it corresponds to villager's objectives and coincides with conducive institutional arrangements and, crucially, an enabling external policy environment. To achieve the full potential of enhancements, research should be aimed at furthering villager's understanding of the status and potential of their resource in terms of these objectives.
103

Relative yield efficiency and some production practices on pearl millet (Pennisetum typhoides (Burm.) Stapf and Hubb.)

Ouendeba, Botorou January 2011 (has links)
Typescript. / Digitized by Kansas Correctional Industries
104

Grain production in China : productivity changes and provincial disparities, 1978-1990 / by Hong Yang.

Yang, Hong January 1994 (has links)
Bibliography :leaves 249-275. / xv, 275 leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Centre for Asian Studies, 1995
105

A study of term structure of interest rates - theory, modelling and econometrics

Chen, Shuling, Mathematics & Statistics, Faculty of Science, UNSW January 2009 (has links)
This thesis is concerned with the modelling of the term structure of interest rates, with a particular focus on empirical aspects of the modelling. In this thesis, we explore the ??-parameterised (?? being the length of time to maturity) term structure of interest rates, corresponding to the traditional T-parameterised (T being the time of maturity) term structure of interest rates. The constructions of Australian yield curves are illustrated using generic yield curves produced by the Reserve Bank of Australia based on bonds on issue and by constructed yield curves of the Commonwealth Bank of Australia derived from swap rates. The data used to build the models is Australian Treasury yields from January 1996 to December 2001 for maturities of 1, 2, 3, 5 and 10 years, and the second data used to validate the model is Australian Treasury yields from July 2000 to April 2004 for maturities of all years from 1-10. Both data were supplied by the Reserve Bank of Australia. Initially, univariate Generalised Autoregressive Conditional Heteroskedasticity (GARCH), with models of individual yield increment time series are developed for a set of fixed maturities. Then, a multivariate Matrix-Diagonal GARCH model with multivariate asymmetric t-distribution of the term structure of yield increments is developed. This model captures many important properties of financial data such as volatility mean reversion, volatility persistency, stationarity and heavy tails. There are two innovations of GARCH modelling in this thesis: (i) the development of the Matrix-Diagonal GARCH model with multivariate asymmetric t-distribution using meta-elliptical distribution in which the degrees of freedom of each series varies with maturity, and the estimation is given; (ii) the development of a GARCH model of term structure of interest rates (TS-GARCH). The TS-GARCH model describes the parameters specifying the GARCH model and the degrees of freedom using simple smooth functions of time to maturity of component series. TS-GARCH allows an empirical description of complete interest rate yield curve increments therefore allowing the model to be used for interpolation to additional maturity beyond those used to construct the model. Diagnostics of TS-GARCH model are provided using Australian Treasury bond yields.
106

Estimates of genetic variability and efficiency of early generation selection for grain yield and protein content in durum wheat crosses (Triticum turgidum. L. var. durum)

Rezgui, Salah 16 August 1993 (has links)
Graduation date: 1994
107

Influence of planting density on spike size and grain yield in five winter wheat cultivars

Wang, Shi Ping, 1956- 09 November 1990 (has links)
Graduation date: 1991
108

Quantitative trait locus mapping of yield and yield components in barley (Hordeum vulgare L.)

Traore, Abdoulaye 23 December 1993 (has links)
Higher grain yield is a key objective in barley (Hordeum vulgare. L) breeding. Despite extensive research on the genetics of yield and its components, selection for yield per se is still the most extensively employed because of negative relationships among components, modest correlations between yield and any particular component, and the additional resources required for measuring the components. The development of quantitative trait locus (QTL) detection procedures allows for an alternative approach to this issue. The objective of this investigation was to determine the biological basis of observed grain yield QTLs, with particular reference to yield components and yield-related traits. Yield and yield component traits were assessed in a population of spring barley doubled haploids from a cross of 'Steptoe' x 'Morex'. The scope of inference of the experiment was broadened by using reference QTL data sets from the multiple environment assessment of the same population. Both positive and negative relationships among yield, component, and related trait QTLs were observed. The QTL data indicate that indirect selection for yield via yield components would be ineffective. The yield QTL effects in this germplasm were largely attributable to lodging and basal internode length. Localization and interpretation of yield QTLs may be useful for studying orthologous gene expression in other germplasm and in developing multiple character selection strategies. / Graduation date: 1994
109

Retail yields and fabrication times for beef subprimals from two grade groups

Voges, Kristin Leigh 17 February 2005 (has links)
Beef subprimals (n = 356), representing USDA Low Choice and Select grades, were obtained from a major beef processor. Selected subprimals represented the normal weight variation and standard packer fat trim levels associated with commodity boxed beef. The subprimals selected included beef rib, blade meat; beef rib, ribeye roll, lip-on, bone-in; beef rib, ribeye roll (0x0); beef rib, ribeye, lip-on (2x2) (5.08 cm x 5.08 cm); beef rib, ribeye, lip-on modified (1x1) (2.54 cm x 2.54 cm); beef rib, ribeye (IM, individual muscle); beef rib, ribeye cap (IM); beef chuck, outside shoulder clod, trimmed; beef chuck, outside shoulder clod, top blade roast; beef chuck, square cut, pectoral meat (IM); beef chuck, chuck roll; beef plate, inside skirt (IM); beef round, top (inside) untrimmed; beef round, outside round (flat); beef round, eye of round (IM); beef loin, strip loin, bone in; beef loin, strip loin, boneless; beef loin, top sirloin butt, boneless, 2-piece; beef loin, bottom sirloin butt, flap boneless (IM); beef loin, bottom sirloin butt, ball tip, boneless; beef loin, bottom sirloin butt, tri-tip, boneless (IM); and beef chuck, outside shoulder, clod M. teres major. Subprimals were fabricated into bone-in or boneless retail or foodservice cuts and associated components by trained retail meat cutters. After each retail cutting test, trained technicians recorded weights of all cuts, lean trim, fat trim, and bone. All retail cuts were trimmed to an eighth of an inch (0.32 cm), unless otherwise specified. Time (s) was recorded for each-cutting test and in two major phases: opening (retrieval of the subprimal from vacuum-packaged bag) and cutting (removal of all external and seam fat, connective tissue, and separation of individual muscles, as well as producing tray ready retail cuts). In general, Select subprimals had higher saleable yields than Choice subprimals. Select subprimals had less trimmable fat than Choice subprimals, and differences in retail yields appeared to follow these factors. Few significant differences were observed for processing times between USDA quality grade groups. These data will serve as an update to the CARDS (Computer Assisted Retail Decision Support) software program.
110

Investigating the relationship between yield risk and agri-environmental indicators

Clark, Nathan J., January 2002 (has links) (PDF)
Thesis (M.S.)--University of Kentucky, 2002. / Title from document title page. Document formatted into pages; contains viii, 51 p. : ill, maps. Includes abstract. Includes bibliographical references (p. 49-50).

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