Organisms Commons^™

Do Plant Secondary Metabolite‐Containing Forages Influence Soil Processes In Pasture Systems?, Andrea K. Clemensen, Juan J. Villalba, George E. Rottinghaus, Stephen T. Lee, Frederick D. Provenza, Jennifer R. Reeve

Wildland Resources Faculty Publications

Grazed pastures are susceptible to N loss from urine/manure additions, which increases eutrophication, affecting the global N cycle. Plant secondary metabolites (PSM), such as condensed tannins (CT) and terpenes, influence silviculture soil dynamics by generally decreasing N mineralization. We investigated whether cattle‐grazed pastures of non‐traditional grass and legume forage monoculture strips including CT‐containing sainfoin (Onobrychis viciifolia Scop.) and tall fescue (TF) [Schedonorus arundinaceus (Schreb.) Dumort.] influenced soil dynamics compared with traditional grass and legume forage monoculture strips of alfalfa (Medicago sativa L.), without tannins, and TF. Throughout the study, CT in sainfoin averaged 58.9 g kg^{−1 …}

Cyanobacteria Dominance In The Oligohaline Waters Of Back Bay, Virginia, Harold G. Marshall

Biological Sciences Faculty Publications

Back Bay and its flora have historically been influenced by the interaction of freshwater flow in combination with frequent intrusion of saline water into its basin. These events have resulted in a dynamic environmental setting influencing the abundance and composition of its phytoplankton community. Dominating these oligohaline waters is a diverse representation and high abundance of freshwater filamentous and colonial cyanobacteria. These include the nonheterocystous Planktolyngbya contorta, Planktolyngbya limnetica, and Pseudanabaena limnetica, taxa implicated as bloom producers in Bay waters with N:P molar ratios ranging from 23:1 to 74:1.

Nitrogen Movement Under Irrigated Corn As Influenced By Nitrogen Source And Rate, Douglas C. Muir

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to determine nitrogen movements under a fall applied fertilizer as affected by rate of application of fertilizer, type of fertilizer carrier, and by crop grown. Two nitrogen fertilizers, calcium nitrate and ammonium sulfate, were applied in the fall of 1970. The soil profile was sampled in the spring of 1971 and again in the fall of 1971. Nitrate-nitrogen from both the calcium nitrate and the ammonium sulfate applications was found to have moved significantly from the time of application to the time of spring soil sampling. Two effects from the high rate of both …

Carbon And Nitrogen As Regulators Of Algal Growth In Treated Sewage, Edward G. Foree, Charles Reece Scroggin

KWRRI Research Reports

Continuous flow algal cultures were grown under three different growth conditions using secondary sewage treatment plant effluent as the growth medium. The only variable within each run was the hydraulic residence time. The concentrations of growth regulating nutrients were varied between the runs so comparisons of the algal mass, composition, nutrient uptake, and genera could be made. The importance of CO₂ availability for algal growth was also studied. A kinetic theory which based algal growth on cellular nutrient concentration was verified. The second phase of the study was a batch culture study in which the same growth medium was …

Factors Regulating The Growth Of Algae In Continuous Culture In Diluted Secondary Sewage Treatment Plant Effluent And Subsequent Biodegradability, Edward G. Foree, Caroline P. Wade

KWRRI Research Reports

Heterogeneous algal cultures were grown in laboratory continuous culture in continuous flow, completely mixed chemostats in secondary sewage treatment plant effluent diluted to give an ammonia nitrogen concentration of 10 mg/1. Variables were lighting, pH, carbon dioxide availability, and hydraulic residence time.

Optimum growth occurred under pH 7.0, excess CO₂, and continuous lighting conditions. The availability of artificially supplied excess CO₂ greatly increased the mass (standing crop) at steady-state over that produced under otherwise identical conditions for all residence times studied. For the case of excess CO₂ availability, the nitrogen concentration in the algal cells regulated …

Algal Growth And Decomposition: Effects On Water Quality, Phase Ii, Edward G. Foree, Ronald L. Barrow

KWRRI Research Reports

The decomposition and associated nutrient regeneration of three unialgal cultures and one mixed culture containing an indigenous population of bacteria and microscopic animals were studied under dark, constant temperature laboratory conditions. After periods of nutrient-deficient growth ranging from O to 30 days, these cultures were inoculated with decomposer populations and subjected to anaerobic and aerobic environments for the decomposition studies. The extend of decomposition was determined from the percentage volatile suspended solids and percentage particulate COD remaining after 200 days of decomposition. The average extent of decomposition was greater for aerobic than for anaerobic conditions. However, significant portions of the …

Algal Growth And Decomposition: Effects On Water Quality, Edward G. Foree, John S. Tapp Jr.

KWRRI Research Reports

The chemical composition of algae grown in batch culture depends mainly on environmental conditions, nutrient availability, presence of predators, cell age, and species. The effects of nutrient availability and cell age on the composition of three unialgal cultures (algae + bacteria) and one hetergeneous culture (algae + bacteria + microscopic animals) were evaluated. The cultures were grown in batch culture under both nutrient-abundant and nutrient deficient conditions and the changes in compositions were observed. Luxurious uptake where nutrients are incorporated into cellular protoplasm at levels greater than those necessary for growth, and super-luxurious uptake, where some nutrients are stored rather …

The Isolation Of Some Nonsymbiotic Nitrogen Fixing Organisms Occurring In Some Utah Soils, Richard B. Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plants require ten elements in appreciable quantity and several others in smaller amount for their continued and normal growth. Three of these necessary elements, nitrogen, phosphorus, and potassium are most important because they occur in the soil in quantities which are usually small in proportion to that needed by the plants. Of these three, nitrogen is in most cases the limiting factor because of the ease with which it may be leached from the soil and comparatively large amount assimilated by plants. These factors coupled with the inhibiting high cost of artificially replacing it in the form of commercial fertilizers, …