Life Sciences Commons^™

Effects Of Nitrogen Management And Cultivar On Strawberry Production Under Disease Pressure, Kamille A. Garcia-Brucher

Master's Theses

Effects of nitrogen management and cultivar on strawberry production under disease pressure

Kamille Garcia-Brucher

California strawberry growers face increasing regulatory pressures to manage nitrogen (N) applications in their production system. Standard practice in the California strawberry industry is to apply a synthetic pre-plant controlled release fertilizer (CRF) to ensure the crop has sufficient N during winter establishment. Some research from the UC Cooperative Extension suggests this practice is not efficient at delivering N to the crop since most of the N is released from CRF before strawberry crop N uptake is significant. Another concern for California strawberry growers is loss …

The Effects Of Substituting True Protein With Non-Protein Nitrogen In Holstein Dairy Heifers Precision-Fed Different Forage To Concentrate Ratios, Noe Alberto Gomez

Animal Science

Understanding the efficiency and digestibility of dietary nutrients in dairy heifers is essential for minimizing costs and environmental impacts of the dairy industry. The objective of this study was to interpret the effects of manipulating rumen-degradable protein (RDP) in a precision feeding system. Eight Holstein ruminally cannulated heifers (14.6 ± 0.1 mo of age, and 386 ± 9.1 kg of weight) were randomly assigned to 2 forage levels: HC (25% forage) and LC (75% forage) and to a degradable protein sequence [0% degradable protein from urea U, 100% casein C (no urea treatment U0); 33% U, 67% C …

Using Stable Isotope Analysis Of Zooplankton To Document Trophic And Biogeochemical Changes In The San Francisco Estuary, Steven C. Westbrook, Julien Moderan

STAR Program Research Presentations

Zooplankton represent a vital link between phytoplankton and fish, like the endangered Delta Smelt. Human interferences (nitrates from waste water, flow alteration, invasive species introduction…) have altered the structure of the San Francisco Estuary (SFE) ecosystem. We use stable isotope analysis to improve our knowledge of the planktonic food web in the SFE and gain insights into its evolution over the past decades. We use the ratios of certain isotopes (Nitrogen, Carbon, Sulfur, etc.) in different species of zooplankton to tell us what it is feeding on as well as the trophic level it feeds in. My research focused on …

Factors Affecting The Reduction Of Carbon To Nitrogen Ratio In Composted Separated Solids, Mark Fagundes

Dairy Science

The objective of the study was to determine the factors involved in the reduction of carbon to nitrogen ratio in composted separated solids. A single compost windrow was laid on a 6,000 jersey cow dairy farm located in Madera County. Samples were obtained from six separate positions on the pile, every other day. Direct pile measurements on the date of sampling included pile temperature (surface and core), height, width and curvature. Samples were removed from the windrow during each sampling meeting to determine the percent dry matter content. The collected samples were sent out to Denele Analytical Inc. to determine …

Effects Of Nitrogen And Potassium Fertilizer On Willamette Spider Mite (Eotetranychus Willamettei) (Acari: Tetranychidae), Whitney Ann Geddes

Master's Theses

The spider mite family (Tetranychidae) is a well known pest group in agriculture. Within this family, Willamette spider mite (Eotetranychus willamettei) causes physical harm and potential damage to grapevines (Vitis vinifera) along the central and north coast of California as well as Washington and Oregon. Willamette spider mite prefers cooler climates and feeds by puncturing the plant leaf tissue; therefore removing plant nutrients in the early stages of plant growth. Amending soils with fertilizer is a common cultural practice used in commercial vineyards, but no study has documented the interaction between the effects fertilizer concentrations have on Willamette spider mite. …

Organic Carbon Content In Surface And Subsurface Soil On A Toposequence On The Peterson Ranch In Poly Canyon, San Luis Obispo, Renee Michelle Nall

Earth and Soil Sciences

Soil organic carbon (SOC) is directly related to soil organic matter (SOM), and is important in the functionality and stability of terrestrial ecosystems. Soil organic carbon is also an important pool for C storage and small changes of SOC may cause significant gains and losses in the large scale carbon cycle. The mechanisms by which SOC is transported and stored however are not widely studied. This study was conducted to determine if there is a relationship between toposequence and SOC in a small watershed on the Peterson Ranch, San Luis Obispo, CA. Nine soil pits were dug on various hillslope …

Late Fall Fertilization Of Kentucky Bluegrass, David J. Wehner, Jean E. Haley, Dennis L. Martin

Office of the Dean (CAFES) Scholarship

Many turfgrass managers apply a portion of the total yearly N to cool-season turfgrasses in the late fall (November). The purpose of this field study was to compare fertilization programs with and without N applications in November using both slow-release and soluble N sources. Turfs of two different cultivars of Kentucky bluegrass (Poa pratensis L. cv. Baron and cv. Newport) growing on a Flanagan silt loam (fine, montmorillonitic, mesic Aquic Argiudoll) received 10 fertilization programs utilizing urea, isobutylidene diurea (IBDU), or sulfur-coated urea (SCU). Urea was applied four times per year with either a spring application or a late-fall application …