Digital Commons Network^™

Advancing Digital Soil Mapping And Assessment In Arid Landscapes, Colby W. Brungard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Soil information is required for arid and semi-arid land management decisions such as permitting livestock grazing or planning vegetation restoration projects. However, traditional soil mapping methods may not provide adequate soil information, because the scale of mapping often requires dissimilar soils to be grouped together and there are no estimates of map uncertainty. Traditional methods are also often too costly or impractical to implement in large, remote, public arid and semi-arid rangelands. Digital soil mapping (DSM) may be able to overcome these limitations. Digital soil mapping is the creation of pixel-based soil maps using quantitative statistical models that relate easily …

Stem Development, Seeding Rate, And Establishment Of Birdsfoot Trefoil (Lotus Corniculatus) For Organic, Grazing-Based Dairies, Sara Hunt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Birdsfoot trefoil (BFT, Lotus corniculatus L.) is a non-bloating, productive forage legume well suited to grazing-based ruminant production. This thesis presents three studies conducted in the Mountain West applicable to organic management and cultivation of BFT. The first is an analysis of lignification in BFT stems that supports recommendations to harvest BFT at approximately 6 weeks of regrowth, or early bloom. Lignification decreases digestibility and is correlated with high shear force required for grazing animals to break BFT stems. The process of stem lignification was observed by harvesting increasingly mature stems; cutting thin sections of the sixth stem internode, which …

Plant And Animal Performance In Tall Fescue And Tall Fescue/Legume Pastures, Troy J. Bingham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tall fescue is the one of most common grasses in irrigated pastures throughout the Intermountain West. Two limitations of tall fescue are a decrease in productivity during hot summer months and the need for supplemental nitrogen (N). The objective of this research was to compare tall fescue-alfalfa (TF+ALF), tall fescue-birdsfoot trefoil (TF+BFT), tall fescue-nitrogen fertilizer (TF+N), and tall fescue without nitrogen fertilizer (TF-N) on forage yield, nutritional quality, and livestock performance. Research plots were established at the Utah State University Pasture Research Facility in Lewiston, UT in 2010 and grazed in 2012 and 2013. Treatments were arranged in a randomized …

Yield And Quality Of First-Year Corn Silage Following Alfalfa Stand Termination As Affected By Tillage, Herbicide, And Nitrogen Fertilizer, Jason Daniel Clark

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Glyphosate-containing herbicides such as Roundup® are a common and highly effective method to terminate alfalfa stands. With the development of glyphosate-resistant (Roundup Ready®) alfalfa, this tool is no longer an option. The purpose of this research was to determine the optimal termination methods to use when rotating from glyphosate-resistant alfalfa into silage corn. Studies were conducted in 2012 and 2013 in Cache Junction and Cornish, Utah using five different combinations of tillage type and timing (fall conventional till, spring conventional till, fall strip-till, spring strip-till, and no-till), four 2,4-D plus dicamba herbicide timings (fall, spring, in-crop, and a control), and …

Biophysically-Based Measurement Of Plant Water Status Using Canopy Temperature, Christopher K. Parry

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Precision irrigation scheduling is one approach that can conserve water by supplying crops with the minimum amount of water needed for sufficient vegetative growth and final crop yield. Improved methods for irrigation scheduling are needed for arid regions that rely mainly on irrigation for crop water needs, and humid regions that supplement water received from precipitation with added irrigation. Methods that directly determine plant physiological responses to water availability have potential to be significantly more sensitive and accurate than indirect approaches like soil moisture measurement. Stomatal conductance is a rapid physiological response to leaf water potential.

Stomatal conductance in single …

Deficit Irrigation Of Kentucky Bluegrass For Intermountain West Urban Landscapes, Hang T. T. Duong

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Due to end users irrigating with excess water, water conservation of turfgrass can make a large impact in urban water conservation by reducing water applied while still maintaining visual appearance. This study was conducted to determine if Kentucky bluegrass (Poapratensis L.) can be deficit irrigated to maintain minimum acceptable appearance while conserving water. The study investigated water stress in terms of stomatal conductance, chlorophyll index, leaf temperature and predawn leaf water potential at the point of water stress, or where visual quality no longer meets expectations during dry down conditions. Water use was measured over well established Kentucky …