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You searched for +publisher:"Colorado State University" +contributor:("Fonte, Steven J."). Showing records 1 – 2 of 2 total matches.

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Colorado State University

1. Junaidi, Fnu. Evaluation of spring wheat genotypic response to soil health promoting management practices.

Degree: MS(M.S.), Soil and Crop Sciences, 2018, Colorado State University

Growing efforts to restore soil organic matter and overall soil health are likely to enhance soil biological communities and promote positive interactions between plants and soil communities. However, modern genotypes bred under intensive management practices may not be able to benefit fully from soil health promoting practices if they have lost their ability to effectively interact with key soil organisms. The purpose of this study was to explore this idea by studying how spring wheat genotypes with different breeding contexts and histories respond to improved soil health achieved via additions of organic matter and soil fauna. A greenhouse experiment with a full factorial complete randomized design was carried out at Colorado State University, Fort Collins, between June and November, 2016. The treatment factors included spring wheat genotype, as well as compost and earthworm additions. The genotypes included a wild ancestor of wheat, Aegilops tauschii, two older genotypes of spring wheat, Gypsum and Red Fife, and two near-isogenic modern genotypes, Scholar Rht2M and Scholar Rht2W, that differ only by the presence of the semi-dwarf allele Rht-D1b in ScholarRht2M. Each wheat genotype was grown in rootboxes (24.5 x 3.5 x 38.0 cm) that received either soils amended with composted manure or not, and with or without the addition of earthworms (two Aporrectodea caliginosa per box). Measurements included plant growth (heading date, number of tillers), biomass (aboveground and root biomass, root:shoot ratio), root morphology (root length and diameter), yield-related traits (number of seeds, seeds weight, average weight per seed, harvest index), nitrogen content (vegetative aboveground and grains), and nitrogen uptake. Findings indicate that interactions between genotypes and soil treatments were inconsistent, and the original hypothesis, that older wheat genotypes would show a greater response to improved soil biological conditions relative to newer genotypes, was not well supported. Overall, the aboveground and yield responses to compost were small compared to the root responses. Composted manure additions, increased root length, biomass, and diameter only in the wild accession (Ae. tauschii) and older Gypsum wheat variety. Modern genotypes, on the other hand, exhibited little root trait plasticity except in root diameter, which decreased with compost additions. Except for a decrease observed in Red Fife, compost effects on aboveground biomass were not significant for most genotypes. Genotype x earthworm interactions were only observed in the vegetative biomass N uptake, and earthworm effects in general were low due to low survival of the earthworms. Ae. tauschii and Gypsum had a more positive response to compost addition for both aboveground and root biomass, indicating that these genotypes may better take advantage of soil health promoting practices. While Gypsum had a similar response to the wild accession when compost was added, Red Fife tended to respond more like the modern genotypes. Overall, my findings suggest… Advisors/Committee Members: Fonte, Steven J. (advisor), Byrne, Patrick F. (committee member), Paschke, Mark W. (committee member).

Subjects/Keywords: Earthworm; Soil health; Spring wheat; Genotype; Compost; Soil organism

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APA (6th Edition):

Junaidi, F. (2018). Evaluation of spring wheat genotypic response to soil health promoting management practices. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/185636

Chicago Manual of Style (16th Edition):

Junaidi, Fnu. “Evaluation of spring wheat genotypic response to soil health promoting management practices.” 2018. Masters Thesis, Colorado State University. Accessed December 15, 2019. http://hdl.handle.net/10217/185636.

MLA Handbook (7th Edition):

Junaidi, Fnu. “Evaluation of spring wheat genotypic response to soil health promoting management practices.” 2018. Web. 15 Dec 2019.

Vancouver:

Junaidi F. Evaluation of spring wheat genotypic response to soil health promoting management practices. [Internet] [Masters thesis]. Colorado State University; 2018. [cited 2019 Dec 15]. Available from: http://hdl.handle.net/10217/185636.

Council of Science Editors:

Junaidi F. Evaluation of spring wheat genotypic response to soil health promoting management practices. [Masters Thesis]. Colorado State University; 2018. Available from: http://hdl.handle.net/10217/185636


Colorado State University

2. Eash, Lisa. Factors contributing to maize and bean yield gaps in Central America vary with site and agroecological context.

Degree: MS(M.S.), Soil and Crop Sciences, 2019, Colorado State University

In Central America, the population and associated food demands are rising rapidly, while yields of their staple crops, maize and beans, remain low in a global context. To identify the main limiting factors to crop production in the region, field trials were established in six priority maize- and bean-producing regions in Guatemala, Honduras and El Salvador. Potential yield-limiting factors were evaluated in the 2017 growing season and included: nutrient management, irrigation, planting arrangement, and/or pest and disease control. When considering all sites, improved fertilization and pest and disease control significantly improved yields in maize by 11% and 16% respectively, but did not have a significant overall effect in beans. Irrigation had no effect in the year studied, due to sufficient and evenly distributed rainfall over the growing season. Optimized planting arrangement resulted in an average 18% increase in maize yield overall, making it the most promising factor evaluated in this study. However, the effectiveness of each factor varied across sites and no factor was effective at increasing yield consistently across all sites. Increased production was not always associated with net economic gains due to the relatively high costs of inputs and technology in the region. The study demonstrated that production constraints are highly dependent on local management practices and agroecological context. Therefore, public and private development efforts that seek to increase production should seek to identify site-specific limitations pertinent to each area in question. Advisors/Committee Members: Fonte, Steven J. (advisor), Khosla, Raj (committee member), Davis, Jessica G. (committee member).

Subjects/Keywords: El Salvador; Honduras; Crop productivity; Production constraints; Guatemala

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Eash, L. (2019). Factors contributing to maize and bean yield gaps in Central America vary with site and agroecological context. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/193161

Chicago Manual of Style (16th Edition):

Eash, Lisa. “Factors contributing to maize and bean yield gaps in Central America vary with site and agroecological context.” 2019. Masters Thesis, Colorado State University. Accessed December 15, 2019. http://hdl.handle.net/10217/193161.

MLA Handbook (7th Edition):

Eash, Lisa. “Factors contributing to maize and bean yield gaps in Central America vary with site and agroecological context.” 2019. Web. 15 Dec 2019.

Vancouver:

Eash L. Factors contributing to maize and bean yield gaps in Central America vary with site and agroecological context. [Internet] [Masters thesis]. Colorado State University; 2019. [cited 2019 Dec 15]. Available from: http://hdl.handle.net/10217/193161.

Council of Science Editors:

Eash L. Factors contributing to maize and bean yield gaps in Central America vary with site and agroecological context. [Masters Thesis]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/193161

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