Digital Commons Network^™

Animal And Pasture Responses To Grazing Management Of Chemically Suppressed Tall Fescue In Mixed Pastures, Jessica A. Williamson

Theses and Dissertations--Plant and Soil Sciences

Treatment of endophyte-infected tall fescue [Lolium arundinaceum (Schreb.) Darbysh] with the broad leaf herbicide Chaparral® can mitigate fescue toxicosis and enhance forage quality by suppressing seedhead emergence. Applying the herbicide to fescue pastures also reduces forage mass and promotes severe spot grazing when pastures are continuously grazed. A grazing experiment was conducted with steers (2013) and heifers (2014) to evaluate animal and plant responses in fescue-bluegrass (Poa pratensis L.) mixtures treated with Chaparral to determine the effects of grazing management on pasture carrying capacity, nutritive values, botanical composition, and animal performance. Continuous and rotational (i.e., four subdivisions to …

Conservation Agriculture In Kentucky: Investigating Nitrogen Loss And Dynamics In Corn Systems Following Wheat And Hairy Vetch Cover Crops, Rebecca Erin Shelton

Theses and Dissertations--Plant and Soil Sciences

Unintentional nitrogen (N) loss from agroecosystems produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, adoption of conservation agricultural management practices, such as no-till and cover cropping, has increased. This study assessed N loss via leaching, NH₃ volatilization, N₂O emissions, and N retention in plant and soil pools of corn conservation agroecosystems across a year. Three systems were evaluated: 1) an unfertilized organic system with cover crops Vicia villosa, Triticum aestivum, or a mix of the two; 2) an organic system with a Vicia cover crop employing three fertilization schemes (0 N, organic N, …

Selection And Basis For 2,4-D (2,4-Dicholorphenoxyacetic Acid) Tolerance In Red Clover (Trifolium Pratense), Tara L. B. Lewis

Theses and Dissertations--Plant and Soil Sciences

A red clover (Trifolium pratense) population (UK), from a cross between the cultivar Kenland and a 2,4-D tolerant population (Florida), was recurrently selected for 2,4-D tolerance with evaluations after the 6^th, 7^th, and 8^th selection cycles. All UK populations were more 2,4-D tolerant than Kenland. The 2,4-D tolerance following the 6^th selection cycle was similar to the Florida population and tolerance was increased following 7 and 8 cycles of selection by removing plants showing 2,4-D injury and doubling the rate of 2,4-D used for selection.

Yield and forage quality were evaluated in …

Nutrient Availability And Dynamics Of Compost Bedded Pack Dairy Barn Waste, Leslie Hammond

Theses and Dissertations--Plant and Soil Sciences

Increased adoption of compost bedded pack dairy barns (CBP), a relatively new housing and manure handling strategy, warrants study to facilitate proper use of CBP waste as a soil amendment. This study: 1) characterized in situ nutrient content and availability of CBP waste in terms of nitrogen (N) and phosphorus (P); 2) examined the decomposition of surface-applied CBP waste compared to an alternative processed solid waste amendment; 3) examined nutrient dynamics of incorporated CBP waste in high and low soil test phosphorus (STP) environments. Quick anaerobic mineralization assays revealed that bed management affects nutrient content and availability of CBP waste. …