Brad Geary

Sports fields are among the most intensively managed soils, raising concerns about their soil health. The primary objective of this study was to compare soil health in sports field soils with other less intensively managed systems. Soil samples ( n = 130) were collected from a diverse range of sports fields and compared to farm fields, urban lawns, undisturbed forests, and nonvegetated sandy soils. Samples were analyzed for a suite of soil health indicators, including biological, chemical, and physical properties. Soil health indicators were generally positively correlated, with stronger relationships among chemical and biological parameters than with physical properties. Across venues, soil health in sports fields was largely comparable to nonsport environments; however, sand‐based sports fields exhibited lower aggregation and tended toward reduced chemical/biological soil health parameters. Vegetation presence was the strongest driver of soil health, with nonvegetated sands consistently showing the lowest values across most indicators. Among venues, forest and golf systems generally exhibited higher soil health metrics, while football fields, especially professional, tended to be the lowest. Deep freezing of samples did not negatively affect soil health indicators but was associated with increased TOC and decreased TIC, suggesting a redistribution of carbon pools. Overall, soil health in sports fields is similar to other venues but varies with vegetation, soil texture, and management intensity, highlighting the importance of sustaining plant cover and minimizing disturbance.

Pathogenesis from soil- and seed-borne fungi can limit the survival and growth of native seeds and seedlings. Fungicides can combat fungal pathogens, but in some studies, fungicide treatments were ineffective at improving seedling emergence over untreated seed. Such studies suggest that low fungal presence due to dry conditions may be the cause of fungicide ineffectiveness in some years and sites. This study tested whether a fungicide treatment’s effectiveness is indeed related to the amount of fungi in the soil. We compared the emergence and biomass produced from Pseudoroegneria spicata seed that was uncoated, coated with no active ingredient, and fungicide-coated, across five soil treatments promoting different levels of fungal biomass. For uncoated seed, both percent emergence and total biomass of seedlings were highest in autoclaved soil and declined when fungi were present, but the level of fungus did not impact emergence or biomass for fungicide-coated seed. When grown in autoclaved, untreated, or low-fungus soils, percent emergence and total biomass from fungicide-coated seeds were not significantly different from uncoated seeds. However, in medium- and high-fungus soils, the percent emergence and total biomass from fungicide-coated seeds were more than two times greater than uncoated seed (p < 0.05). These results indicate that fungicide treatments can be effective at increasing restoration success for P. spicata, but the effectiveness of the fungicide treatment depends on the microbial environment of the planting site.

Limited data are currently available characterizing the thermal resistance of foodborne pathogens in semolina flour and intermediate pasta matrices representative of commercial conditions during processing. Pasta producers require these data to be compliant with federal regulations since Salmonella spp. and Escherichia coli demonstrate survival in flour and dried pasta products. This study investigated the heat resistance of Salmonella , pathogenic E. coli, and E. faecium NRRL B‐2354 in semolina flour and partially dried pasta intermediates via thermal death time (TDT) studies. The appropriateness of E. faecium NRRL B‐2354 as a surrogate in semolina flour and pasta matrices was determined. Inoculated pasta matrices equilibrated to target water activities of 0.85, 0.88, and 0.91 (at 25°C) underwent isothermal inactivation treatments at 65°C, 70°C, and 75°C. Serial dilution and direct plating methods allowed for the estimation of bacterial survival at each treatment. In representative pasta matrices, the D values for each microorganism increased as water activity decreased from 0.91 to 0.85. Surprisingly, Salmonella and E. coli did not exhibit significantly different thermal resistance in pasta. The greatest heat resistance was seen in semolina flour ( a _w 0.45). E. faecium was significantly more thermal resistant than both pathogens in all treatments when the temperature was ≤ 70°C. The results show that E. faecium strain NRRL B‐2354 is not an ideal proxy for Salmonella and E. coli in semolina and pasta matrices. Analysis of the TDT data also found that a long‐goods pasta drying process can achieve ≥ 7‐log reductions of Salmonella and E. coli when following good manufacturing practices.

Restoring native plant species on degraded landscapes is challenging. Symbiotic partners in the plant rhizosphere can aid in nutrient acquisition, pathogen protection, stress tolerance, and many other processes. However, these microbes are often absent in altered landscapes and need to be re-integrated to improve restoration efforts. We evaluated, within a laboratory setting, the ability of commercial and indigenous rhizobia strains to form nodules on lupine species used for rangeland seedings in the Great Basin region of the Western United States and ascertained if these strains could be applied through a seed coating. We also evaluated if a compost amendment applied via seed coating could further enhance the performance of the rhizobia strains. Our analysis showed that successful nodulation could occur using commercial and wildland-collected indigenous strains through either a liquid culture applied to seedlings or as a dry seed coating. However, the number of root nodules and the presence of a pink color (indicating nitrogen fixation) were typically higher in the commercial product than in the indigenous strains. Compost did not improve nodulation or the performance of the nodules; however, this treatment alone improved shoot growth. Overall, these results suggest that commercial rhizobium may be more effective in improving plant growth, and future research with native rhizobia may want to consider identifying strains compatible with seed-coating delivery. Longer-term studies are now merited for assessing how the rhizobia strains evaluated in this study influence plant growth, particularly in a field setting.

The reclamation of disturbed lands worldwide is a difficult and increasing problem. In the Mountain West region of the United States, mining activities commonly occur in zones dominated by native woody plants. The restoration of woody plants in these areas is challenging, and direct seeding efforts result in poor seedling emergence and establishment. Therefore, seedling transplants are often used, but they frequently experience high mortality during the first year, particularly due to summer stresses. We evaluated if the Groasis Waterboxx device could be used to mitigate drought stress on seedling transplants and improve their establishment on a reclaimed waste rock dump. The Waterboxx device collects precipitation into a polypropylene reservoir and slowly dispenses water onto the soil next to the seedling. To test such a hypothesis, 400 seedlings from five native woody plants (Atriplex canescens, Cercocarpus ledifolius, Pinus edulis, Purshia tridentata, and Rhus glabra) were planted with and without a Waterboxx. The Waterboxx device improved soil water potential, at 40 cm, it took 1 month longer to go below −1 MPa under a Waterboxx. Survival increased 30–65% in four of the five species, and seedling vigor increased for three of the five species. Vigor was higher with all plant species at both planting times and was significantly better in 50% of comparisons. Results support the use of the Waterboxx for improving seedling establishment on mineland overburden sites in the semiarid mountain west. The effectiveness of the Waterboxx device provides merit for future testing where drought challenges seedling establishment.

Many plant species exhibit strong seed dormancy. This attribute benefits the species’ long-term survival but can impede restoration when rapid establishment is required. Soaking seeds in gibberellic acid (GA₃) can overcome dormancy and increase germination but this treatment may not be effective outside the laboratory. An easier and potentially more effective method to apply this hormone is to coat seeds with a GA₃-impregnated polymer. Seed dormancy can also be mitigated by creating a favorable microsite with increased soil moisture. We compared the emergence and establishment of penstemon seeds coated with GA₃ to those of uncoated seeds planted in shallow drill rows versus deep, U-shaped furrows. Overall, 6 times more Palmer’s penstemon (Penstemon palmeri; p < 0.01) and 21 times more thickleaf penstemon (P. pachyphyllus; p < 0.001) established when coated with GA₃, but GA₃ coating did not affect the establishment of firecracker penstemon (P. eatonii; p = 1). Establishment was higher from deep furrows than shallow rows (p < 0.001). These results indicate that GA₃ seed coating and deep, U-shaped furrows may improve the restoration success of some native forbs by breaking dormancy and providing a favorable microsite. Land managers could use these techniques to restore native forbs in dry, disturbed areas.

Maintaining a healthy soil microbiome is important for key soil functions and plant growth. However, little is known about temporal changes in soil microbial communities across different soils and nitrogen fertilization in production soils. The aim of this investigation was to determine soil bacterial and fungal baseline communities and seasonal changes in cornfields, under contrasting soil orders with and without nitrogen fertilization. Three Missouri soil orders (Entisol, Alfisol, and Mollisol) and two nitrogen fertilizer rates (0 and 225 kg nitrogen ha-1) were used for this research. Soil samples (0-5 and 5-15 cm) were taken six times during the season, starting prior to planting up to the R2 corn growth stage. Samples were used to determine bacterial and fungal abundancies and biomass. Soil characteristics (e.g., CEC, pH, organic matter) and nitrogen fertilization showed significant but minor influence on bacterial abundance and biomass, while soil order and corn growth stage had major influence. Each soil order had a distinct and significantly different bacterial and fungal community. Soil depth significantly influenced all Beta diversity metrics, and bacterial and fungal biomass were greater in the 0-5 cm depth. No microbial interactions influenced corn growth more than nitrogen. Though strong relationships between microbes and soil and plant health have been shown, linkages of microbiome information to agronomic decisions are rare. Before developing soil microbial information based decision aids for farmers, longer temporal sampling in more growing environments are needed to identify links between management practices and microbial information.

Astragalus utahensis (Torr.) Torr. & A. Gray (Fabaceae) (Utah milkvetch) is native to the arid Great Basin and has desirable attributes that make it a good candidate for restoration in arid, noncompetitive situations. Seed dormancy is a significant barrier to consistent establishment for this species. Species of Alternaria and Aspergillus fungi have potential to enhance germination of A. utahensis seed; therefore, we conducted trials to investigate Alternaria and Aspergillus effects on germination and emergence under controlled in vitro conditions or in soil in a growth chamber, in a greenhouse, and in the field. Seed was either acid scarified or left untreated and then inoculated with spores from Alternaria and Aspergillus. Under in vitro and greenhouse conditions, rates of germination or emergence increased significantly for seed inoculated with the 2 fungi. Inoculated seed in field experiments planted at Fountain Green and Nephi, Utah, had significantly higher emergence rates than the non-scarified/non-inoculated control, and Aspergillus-inoculated seed outperformed seed treated with Alternaria. Inoculation of seed planted at Spanish Fork did not provide an advantage over acid scarification, but all treatments showed greater emergence than the non-scarified/non-inoculated control. This study demonstrates that inoculating A. utahensis seed with Alternaria or Aspergillus prior to planting has a positive impact on rates of emergence in a field setting.

The Ascomycete fungus, Pyrenophora semeniperda, attacks a broad range of cool-season grasses. While leaf and predispersal infection of seeds (i.e., florets containing caryopses) have been previously characterized, little is known about the pathogenesis of mature seeds following dispersal. In this study, we examined infection and disease development of P. semeniperda on dormant seeds of Bromus tectorum. Inoculated seeds were hydrated at 20°C for up to 28 days. Disease development was characterized using scanning electron and light microscopy. P. semeniperda conidia germinated on the seed surface within 5 to 8 h. Hyphae grew on the seed surface and produced extracellular mucilage that eventually covered the seed. Appressoria formed on the ends of hyphae and penetrated through the lemma and palea, stomatal openings, and broken trichomes. The fungus then catabolized the endosperm, resulting in a visible cavity by 8 days. Pathogenesis of the embryo was associated with progressive loss of cell integrity and proliferation of mycelium. Beginning at approximately day 11, one to several stromata (approximately 150 μm in diameter and up to 4 mm in length) emerged through the lemma and palea. Degradation of embryo tissue was completed near 14 days. Conidiophores produced conidia between 21 and 28 days and often exhibited “Y-shaped” branching. This characterization of disease development corrects previous reports which concluded that P. semeniperda is only a weak seed pathogen with infection limited to the outermost seed tissues. In addition, the time required for disease development explains why infected dormant or slow-germinating seeds are most likely to experience mortality.