Mutualistic relationships between endophytic fungi and grasses have shown to improve the hardiness of the host. This relationship is common in grasses, including North American native grasses that are important in both forage and grassland ecosystems. Elymus species, such as Canada wildrye (CWR), commonly host the endophytic fungi, Epichloё, while southeastern wildrye (SEWR) may not. In this study, seed of CWR and seed and leaves from local SEWR were assessed for endophyte infection. Infection status was confirmed via histological analysis of seed squashes and leaf peels. Presence/absence of endophyte was determined by scanning for mycelia within seed and between leaf epidermal cells. Following assessment, all SEWR germplasm were endophyte-free (E-), while CWR was endophyte-infected (E+). Endophyte- infected CWR seed were used to isolate and culture the symbiotic endophyte. Isolated endophyte was used to infect E- SEWR. Infection status of SEWR was determined using leaf peels and PCR. This research will help determine if artificial endophyte infection can be performed in SEWR.

Soil-borne pests and pathogens, such as Verticillium dahliae, can devastate a wide range of annual and perennial crops. Current management options for organic production are limited and sustainable management of pathogens, weeds, and arthropods is important for staying profitable and reducing the use of harmful chemicals. Organic soil amendments play an important role in supplying some of the nutritional needs of vegetable crops and improving soil structure, while also contributing to pest control. The objective of this research was to determine the effects of grape and olive-based composts on soil pathogen load, arthropod communities, and weed biomass and diversity. Field experiments were conducted in both organic and conventionally grown bell pepper (Capsicum annuum L.) systems during the summer growing season of 2018 on the Cal Poly campus in San Luis Obispo, California. Four different organic amendment treatments were tested including: olive based compost, grape based compost, dairy manure compost, and plant waste compost. Abundance of the fungal pathogen Verticillium dahliae was assessed from composite soil samples collected at several time points throughout the growing season. Olive, grape, and plant waste composts all displayed significant reduction of V. dahliae abundance between two to eight weeks post application of treatment when compared to the control. Insufficient evidence was found correlating farm management type with V. dahliae abundance after adjusting for treatment and time. Total dry weed biomass was assessed after one month of unhindered growth. The organic amendments tested appeared to alter weed species composition but not overall biomass though no significant differences were found. The soil arthropods symphylans and collembolans were sampled throughout the growing season, significant trends in population were found over time but not across treatments. This research demonstrates how agricultural waste-based compost amendments have potential as tools in pest management.

Studien syftar till att klargöra nuläget i den svenska skogsbaserade bioekonomin. För- och nackdelar med olika utvecklingsmöjligheter har studerats, begränsningar finns för utvecklingen och framtidsmöjligheterna för en cirkulär bioekonomi i Sverige. Den dominerande råvarubasen för den cirkulära bioekonomin i Sverige är skogen. I dagsläget är det framför allt massa-, pappers- och sågverksindustrin som är väl utvecklad och kan räknas till en framgångsrik cirkulär bioekonomi i Sverige. En cirkulär bioekonomi bidrar till en grön omställning för att fasa ut användningen av fossila råvaror, vilket anses vara den största fördelen. Politiska beslut både i Sverige och inom EU kan genom vissa lagförslag begränsa tillgången på råvaror, det är också det största hotet. Möjligheterna är främst långsiktiga spelregler, där tydliga ramverk, affärsmodeller och bioekonomistrategier tas fram.

The effect of post-weaning supplementation of April-born Polypay and White Dorper lambs grazing alfalfa/orchardgrass pasture during two grazing seasons from June to September was studied. One hundred seventy Polypay and 133 White Dorper lambs were randomly allotted to supplemented (2% BW daily) and unsupplemented groups. It was discovered that Polypay lambs weighed more than White Dorpers at wearning, when the grazing season began, and at the end of the 80 (Year 1) and 85 (Year 2) grazing season (P < 0.01). Polypay lambs gained faster (P < 0.01) than White Dorpers. Supplemented lambs gained faster (P < 0.01) than unsupplemented and Polypays had a greater response to supplementation (P < 0.01) than White Dorpers. Polypays had higher (P < 0.01) fecal egg counts, an indicator of Haemonchus contortus infestation. Supplementation did not have any consistent effect on reducing Haemonchus contortus infestation. Differences in forage characteristics of Polypay and White Dorper lambs did appear. Differences in alfalfa and orchardgrass dry matter, neutral detergent fiber, acid detergent fiber, and crude protein availability were measured by subtracting enter from exit availabilities. The largest decrease of alfalfa components from exit to enter was found with unsupplemented Polypays. No consistent effect was found for orchardgrass components.

In recent decades, there has been a rapid expansion in the use of manufactured nanoparticles (MNPs). Experimental evidence and material flow models predict that MNPs enter wastewater treatment plants and partition to sewage sludge and majority of that sludge is land applied as biosolids. During wastewater treatment and after land application, MNPs undergo biogeochemical transformations (aging). The primary transformation process for silver MNPs (Ag-MNPs) is sulfidation, while zinc oxide MNPs (ZnO-MNPs) most likely undergo phosphatation and sulfidation. Our overall goal was to assess bioavailability and toxicogenomic impacts of both pristine, defined as-synthesized, and aged Ag- and ZnO-MNPs, as well as their respective ions, to a model organism, the soil nematode Caenorhabditis elegans. We first investigated the toxicity of pristine Ag-MNPs, sulfidized Ag-MNPs (sAg-MNPs), and AgNO3 to identify the most sensitive ecologically relevant endpoint in C. elegans. We identified reproduction as the most sensitive endpoint for all treatments with sAg-MNPs being about 10-fold less toxic than pristine Ag-MNPs. Using synchrotron x-ray microspectroscopy we demonstrated that AgNO3 and pristine Ag-MNPs had similar bioavailability while aged sAg-MNPs caused toxicity without being taken up by C. elegans. Comparisons of the genomic impacts of both MNPs revealed that Ag-MNPs and sAg-MNPs have transcriptomic profiles distinct from each other and from AgNO3. The toxicity mechanisms of sAg-MNPs are possibly associated with damaging effects to cuticle. We also investigated the effects pristine zinc oxide MNPs (ZnO-MNPs) and aged ZnO-MNPs, including phosphatated (pZnO-MNPs) and sulfidized (sZnO-MNPs), as well as ZnSO4 have on C. elegans using a toxicogenomic approach. Aging of ZnO-MNPs reduced toxicity nearly 10-fold. Toxicity of pristine ZnO-MNPs was similar to the toxicity caused by ZnSO4 but less than 30% of responding genes was shared between these two treatments. This suggests that some of the effects of pristine ZnO-MNPs are also particle-specific. The genomic results showed that based on Gene Ontology and induced biological pathways all MNP treatments shared more similarities than any MNP treatment did with ZnSO4. This dissertation demonstrates that the toxicity of Ag- and ZnO-MNPs to C. elegans is reduced and operates through different mechanisms after transformation during the wastewater treatment process.

The entire stretch of the Ohio River is under fish consumption advisories due to contamination with polychlorinated biphenyls (PCBs). In this study, natural attenuation and biostimulation of PCBs and microbial communities responsible for PCB transformations were investigated in Ohio River sediments. Natural attenuation of PCBs was negligible in sediments, which was likely attributed to low temperature conditions during most of the year, as well as low amounts of available nitrogen, phosphorus, and organic carbon. Moreover, surface sediments were relatively oxidized, as indicated by the prevalence of aerobic bacteria such as beta- Proteobacteria, alpha-Proteobacteria, Sphingobacteria, and Nitrospira in 16S rRNA sediment clone libraries. On the other hand, several reductive dechlorinators were detected in sediments, including Dehalococcoides, Desulfitobacterium spp. which suggested that reductive dechlorination might be possible in sediments under certain biogeochemical conditions. Considerable amounts of PCBs were transformed by reductive dechlorination (80% in 177 days by pattern N) when sediments were maintained under anaerobic conditions, amended with nutrients and organic carbon, and incubated at 25 ºC in lab microcosms. Analysis of 16S rRNA clone libraries from these treatments revealed that Bacteroidetes, Chloroflexi and Firmicutes were enriched and Proteobacteria were depleted compared to clone libraries from treatment without organic amendments. Reductive dechlorination was decreased in sediments incubated at 10 and 40 ºC, and was not affected by FeSO4 amendments compared to unamended sediments incubated at 25 ºC. Transformations of PCB-153 were investigated in sediments under anaerobic, aerobic and sequential anaerobic and aerobic conditions. Transformations were only observed in treatments with an anaerobic phase, which occurred by reductive dechlorination by pattern N. Neither PCB-153 nor dechlorination products PCB-99 or PCB-47 were transformed under aerobic conditions. Analysis of 16S rRNA clone libraries revealed that Bacteoridetes, Chloroflexi, and Firmicutes were enriched under anaerobic conditions and Proteobacteria were enriched under aerobic conditions. Results from this study revealed that natural attenuation and biostimulation were not effective at removing PCBs from Ohio River sediments. Hence, other remediation methods will need to be employed to decrease PCB levels in this ecosystem.

The study was aimed to provide information on local biomass development during crop growth using ground based optical sensors and to incorporate the local crop status to a crop growth simulation model to improve understanding on inherent variability of crop field. The experiment was conducted in a farmer’s field located near Princeton in Caldwell County, Western Kentucky. Data collection on soil, crop and weather variables was carried out in the farm from 2006 December to 2008 October. During this period corn (Zea mays L.) and winter wheat (Triticum sp) were grown in the field. A 450 m long representative transect across the field consisting of 45 locations each separated by 10 m was selected for the study. Soil water content was measured in a biweekly interval during crop growth from these locations. Measurements on crop growth parameters such as plant height, tiller count, biomass and grain yield were able to show spatial variability in crop biomass and grain yield production. Crop reflectance measured at important crop growth stages. Soil water sensing capacitance probe was site specifically calibrated for each soil depth in each location. Various vegetation indices were calculated as proxy variables of crop growth. Inherent soil properties such as soil texture and elevation were found playing a major role in influencing spatial variability in crop yield mainly by affecting soil water storage. Temporal persistence of spatial patterns in soil water storage was not observed. Optimum spatial correlation structure was observed between crop growth parameters and optical sensor measurements collected early in the season and aggregated at 2*2 m2 sampling area. NDVI, soil texture, soil water storage and different crop growth parameters were helpful in explaining the spatial processes that influence grain yield and biomass using state space analysis. DSSAT was fairly sensitive to reflect site specific inputs on soil variability in crop production.

This thesis intends to introduce the reader to the concept and benefits of aquaponic farming. The paper begins with an introductory definition of aquaponics, a brief history of aquaponic practices, and a status quo of the industry - all meant to contextualize this concept which is, to the general public, widely unknown. Comparisons are then given to competing technologies which are likely more familiar to most. Specifically, the advantages of aquaponic cultivation are weighed against traditional soil farming, hydroponics, and aquaculture. Current limitations facing the industry are discussed before the thesis concludes with an overview of arguments made.

Head lettuce, Lactuta sativa var. capitata, is susceptible to a number of economically important diseases, the most frequent being russet spot, rib discoloration, and vascular browning (28), which have been shown by Ceponis and Friedman (7) to be caused by Pseudomonas marginalis. Pseudomonads are common plant pathogens and cause such diseases as halo blight in beans (20), bacterial blight in soybeans (20), and bacterial wilt of the bird-of-paradise (27) and tobacco (24). Plants that develop symptoms similar to russet of lettuce are oats, infected by Pseudomonas cichorii, and tobacco infected with Pseudomonas tobaci (34). In general, russet symptoms include few to numerous yellow, pink, brown, olive brown or dark brown irregular specks ranging in diameter from 1/16 to 1/8 inch (28). In tobacco these lesions are thought to result from a necrotizing toxin, diamino-dicarboxylic acid, beta-hydroxy-alpha, epsilon-aminopimelic acid, produced by the bacteria (34). In lettuce these lesions result from the bacterial enzymes, protopectinase and pectin depolymerase (7). The red discoloration of lettuce often encountered in grocery stores and home refrigerators has been given the name russet spot, rib discoloration, and tipburn, depending upon where the discoloration occurs (26). These terms are sometimes used interchangeably in the literature. This investigation was initiated for two purposes: to determine factors which could be responsible for the symptoms which diseased market lettuce develops; and to investigate a preservation procedure that would best control the incidence of this disease.

The potential of Barsoy barley (Hordeum vulgare L.) as a silage crop was studied at Western Kentucky University in 1970-1971. The field study was conducted at two locations. Barley was seeded at the rate of 107.5 kg/ha in a Pembroke silt loam soil at both locations in September, 1970. At the time of planting the soil was fertilized with 7.5, 32.4 and 33.1 kg/ha of nitrogen, phosphorus, and potassium, respectively. Plants at location 2 received an additional 23.7 kg/ha of nitrogen in February, 1971. Whole barley plants were harvested at weekly intervals from March 11 through June 3 at Location 1 and from April 22 through June 3 at Location 2. Based upon the results for dry matter yield, chemical composition, and dry matter percentage, the dough stage of maturity was found to be the most desirable stage for ensiling barley plants. At this stage dry matter yields were 5.4 and 12.4 metric tons per hectare for Locations 1 and 2, respectively. Dry matter percentages were 32.5 for plants at Location 1 and 33.0 for plant at Location 2. Chemical composition percentages for plants at Location 1 were: crude protein 8.3, crude fiber 28.8 nitrogen free extract 54.7, ether extract 1.1, and ash 7.1. Chemical composition percentages for plants at Location 2 were: crude protein 11.5, crude fiber 33.8, nitrogen free extract 47.0, either extract 0.5, and ash 7.2.