Phosphorus speciation, mineralization, and uptake by corn in a soil amended with liquid swine manure

The soil application of liquid swine (Sus scrofu domesticus) manure as a source of P for crop production provides a means for the utilization of waste material. Manure rates have usually been based upon manure N concentrations, but this has sometimes resulted in excess P loadings due to the high N requirement of some crops, as well as the lower availability of N in manures relative to that of P. Applying higher than recommended P rates may result in greater runoff losses, which could lead to eutrophication of surface waters. As a result, future regulations may require that manure applications be based on P rather than N content, which would increase the amount of land needed for application. A two-year field study was conducted to examine the variability in nutrient content of soil-applied liquid swine manure, to determine the effects of liquid swine manure application on the distribution of soil P fractions, and to assess the availability of manure P to com (Zea mays L.). Liquid swine manure was surface-applied to plots in an attempt to provide 15, 30, and 60 kg P ha-1. Control plots received 60 kg P ha-1 as triple superphosphate and 170 kg N ha-1 as ammonium nitrate. Manure plots also received 170 kg N ha-1 by assuming 40 percent availability of manure N and using ammonium nitrate to supplement the deficit. Plots were planted with \u27DeKalb 689\u27 and \u27Pioneer 3343\u27 varieties of com. Prior to and after manure application and when com was at four leaf, ten leaf, and silking growth stages, depth incremented soil samples were collected for P analysis. Plant samples were also collected at each growth stage. Soil samples were analyzed to determine total and organic P, and a sequential dissolution procedure was used to fractionate the inorganic P into operationally defined aluminum (Al-P), calcium (Ca-P), iron (Fe-P), and reductant-soluble (Red-P) phosphate chemical pools. Available P was estimated using Olsen and Mehlich 3 extractants. Plant samples were analyzed for P content, and yields were calculated from grain harvested from the plot center rows. Nutrient concentrations in liquid swine manure were highly variable, and resulted in lower than expected P application rates. In 1992, manure P rates were 17, 32, and 49 kg ha-1 while 1993 rates were 5, 11, and 22 kg ha-1. Effects of P rate on soil P concentrations were observed only in samples taken from the surface 10 cm. Of the inorganic P fractions measured, Al-P was most responsive to P application. Mehlich 3 and Olsen extractable P were also consistently affected by manure and fertilizer application. Manure P was generally less effective than triple superphosphate in maintaining or increasing soil P levels. Com yields were not affected by manure or TSP addition in either year. Ear leaf P content increased with P rated in 1992 but was unaffected in 1993. Correlation of P uptake with soil P fractions suggested that Al-P and Mehlich 3 P were the most accurate predictors of P availability, but correlation coefficients were low and not consistent between years. In order to assess P fertility status in this manure-amended soil, methodologies are needed which are more sensitive to changes in the pool of available P

Transport of imazethapyr in undisturbed soil columns as related to imazethapyr persistence in soil solution

The soil fate and transport of imazethapyr [(±)-2-[4,5- dihydro-4-methyl-4- (1-methylethyl) -5-oxo-1H-imidazole-2-yl] - 5-ethyl-3-pyridinecarboxylic acid] was evaluated in soil solution and undisturbed column leaching studies. Soil solution studies provided information as to the diffusion controlled fate of imazethapyr and column leaching indicated the relative magnitude of diffuse versus channelized flow to the vertical transport of imazethapyr through the soil profile. Laboratory experiments were conducted to determine the effects of application rate, wheat (Triticum aestivum L.) straw addition, and incubation time on the concentration of imazethapyr in soil solution. Field-moist loam (clayey, kaolinitic, thermic Typic Hapludult) Ap horizon was amended with finely ground wheat straw at rates of 0 and 2 g kg-1 and imazethapyr was applied at rates of 0, 31, 62, and 124 μg kg-1. Soil solution was obtained by vacuum displacement at times of 0, 1, 2, 4, 8, and 16 days after application and analyzed to determine liquid-phase imazethapyr concentration. The concentration of imazethapyr in solution decreased exponentially as a function of time, and tended to be higher in solution from the straw-amended samples. Variation in Kd as a function of equilibration time may have been a consequence of diffusion-limited movement of imazethapyr into micropores. For days 0 to 8, the Kd tended to be lower for straw-amended versus unamended soil, perhaps as a consequence of competitive exclusion of imazethapyr by straw for sorption sites in the soil solid phase. A tractor-mounted core sampler was constructed to obtain large undisturbed soil columns for a leaching study. An 89 000 N hydraulic cylinder was used to push a steel sampling cylinder containing schedule 40 PVC pipe into the soil. The hydraulic cylinder was then retracted to pull the pipe and enclosed soil from the ground, with the soil separating evenly at the bottom of the column. Columns 30 cm in diameter were taken to a depth of 68 cm, with compaction observed to be less than three percent. Undisturbed soil columns were mounted vertically in the laboratory and deionized water applied at a rate of approximately 90 mL h-1. After two weeks of wetting, a tension of -0.5 kPa was applied to the bottom of one column, while another column was subjected to a tension of -2 kPa. A 25 mL pulse of 100 mmol L-1 Br-1 and 0.518 mmol L-1 imazethapyr was applied to the surface of each column. Leachate was collected as a function of time and analyzed to determine Br-1 and imazethapyr concentrations. Breakthrough curves were asymmetrical and characterized by rapid appearance of both solutes in the column effluent, with maximum concentrations occurring well ahead of one pore volume of the column. Breakthrough curves were analyzed with the one-dimensional convection-dispersion equation to determine transport parameters and predict the elution of the solutes. The first order decay constant for imazethapyr in soil solution was useful in predicting the breakthrough of imazethapyr after determining transport parameters from the Br-1 data, but distribution coefficients predicted by the model were lower than those determined from soil solution

Flamingo Vol. IX N 3

Anonymous. Untitled. Prose. 1. Anonymous. Untitled. Prose. 2. Anonymous. Untitled. Prose. 3. Ollapod, Cornell. Untitled. Prose. 3. Anonymous. Untitled. Prose. 4. Anonymous. Untitled. Prose. 5. Smith, Reed. Untitled. Cartoon. 8. Anonymous. Gripes and Groans . Prose. 9. J.C.K. You Disgraceful Being, She Said . Picture. 10. Anonymous. Untitled. Prose. 10. Anonymous. Homecoming . Prose. 1. Anonymous. My Girl . Prose. 1. McDonald, George. Untitled. Picture. 11. O\u27Dell, Dorothy. Edifying Adventures of Alice (In Wonderland) . Prose. 12. Anonymous. I. Though Stuff . Prose. 12. Anonymous. Untitled. Prose. 12. Anonymous. Untitled. Prose. 15. Anonymous. Hi-Glims of Denison\u27s History . Prose. 16. Anonymous. Hi-Glims of Denison\u27s History . Picture. 16. Anonymous. Untitled. Prose. 16. Anonymous. Geography of a Single Woman\u27s Life . Prose. 16. Anonymous. II. Hard-Up Stuff . Prose. 16. Anonymous. Fraternity Bridge . Prose. 16. Anonymous. Introducing-Miss 1931 . Prose. 17. Anonymous. III. Big (Bad) Stuff) . Prose. 18. Anonymous. Untitled. Prose. 18. Anonymous. With Horseradish honors . Prose. 18. Anonymous. It\u27s Best Friends . Prose. 18. Anonymous. Table Talk . Prose. 19. Anonymous. Untitled. Prose. 19. Anonymous. IV. Blankety-Blank Stuff . Prose. 19. Anonymous. V. Mighty (Old) Stuff). Prose. 20. Anonymous. Untitled. Prose. 20. Anonymous. Untitled. Prose. 21. Anonymous. Homecoming . Picture. 21. Shiokawa, Richard K. Untitled. Picture. 21. Anonymous. Ain\u27t It So . Prose. 21. Anonymous. book Nook . Prose. 22. Anonymous. Untitled. Prose. 26. Life. Untitled. Prose. 26. Wampus. Untitled. Prose. 26. Anonymous. Untitled. Prose. 27. Gargoyle. Untitled. Prose. 27. Froth. Untitled. Prose. 27. Anonymous. Untitled. Prose. 28. Texas Ranger. Untitled. Prose. 28. Medley. Untitled. Prose. 28. Gargoyle. Untitled. Prose. 29. Cracker. Untitled. Prose. 29. Harvard Lampoon. Untitled. Prose. 29. Texas Ranger. Untitled. Prose. 29. Frivol. Untitled. Prose. 29. Princeton Tiger. Untitled. Prose. 30. Barnacle. Untitled. Prose. 30. Beanpot. Untitled. Prose. 30. Gargoyle. Untitled. Prose. 30. Pup. Untitled. Prose. 31. Pennsylvania Punch Bowl. Untitled. Prose. 31. Penn State Froth. Untitled. Prose. 31. Anonymous. Untitled. Prose. 32. Gargoyle. Untitled. Prose. 32. Smrcina, Orville. Things That Freshmen Do Know . Picture. 13

Untangling the Biological Contributions to Soil Stability in Semiarid Shrublands

Communities of plants, biological soil crusts (BSCs), and arbuscular mycorrhizal (AM) fungi are known to influence soil stability individually, but their relative contributions, interactions, and combined effects are not well understood, particularly in arid and semiarid ecosystems. In a landscape-scale field study we quantified plant, BSC, and AM fungal communities at 216 locations along a gradient of soil stability levels in southern Utah, USA. We used multivariate modeling to examine the relative influences of plants, BSCs, and AM fungi on surface and subsurface stability in a semiarid shrubland landscape. Models were found to be congruent with the data and explained 35% of the variation in surface stability and 54% of the variation in subsurface stability. The results support several tentative conclusions. While BSCs, plants, and AM fungi all contribute to surface stability, only plants and AM fungi contribute to subsurface stability. In both surface and subsurface models, the strongest contributions to soil stability are made by biological components of the system. Biological soil crust cover was found to have the strongest direct effect on surface soil stability (0.60; controlling for other factors). Surprisingly, AM fungi appeared to influence surface soil stability (0.37), even though they are not generally considered to exist in the top few millimeters of the soil. In the subsurface model, plant cover appeared to have the strongest direct influence on soil stability (0.42); in both models, results indicate that plant cover influences soil stability both directly (controlling for other factors) and indirectly through influences on other organisms. Soil organic matter was not found to have a direct contribution to surface or subsurface stability in this system. The relative influence of AM fungi on soil stability in these semiarid shrublands was similar to that reported for a mesic tallgrass prairie. Estimates of effects that BSCs, plants, and AM fungi have on soil stability in these models are used to suggest the relative amounts of resources that erosion control practitioners should devote to promoting these communities. This study highlights the need for system approaches in combating erosion, soil degradation, and arid-land desertification

Nutrient Source and Tillage Effects on Maize: I. Micrometeorological Methods for Measuring Carbon Dioxide Emissions

There is a need to understand the potential benefits of using the biotechnology waste by‐product from manufacturing as a fertilizer replacement in agriculture, by quantifying the economic value for the farmer and measuring the environmental impact. Measuring CO2 emissions can be used to assess environmental impact, including three widely used micrometeorological methodologies: (i) the Bowen Ratio Energy Balance (BREB), (ii) aerodynamic flux‐gradient theory, and (iii) eddy covariance (EC). As a first step in quantifying benefits of applying biotechnology waste in agriculture, a detailed examination of these three methods was conducted to understand their effectiveness in quantifying CO2 emissions for this specific circumstance. The study measured micrometeorological properties over a field planted to maize (Zea mays L. var. indentata ), one plot treated with biotechnology waste applied as a nutrient amendment, and one plot treated with a typical farmer fertilizer practice. Carbon dioxide flux measurements took place over 1 yr, using both BREB and EC systems. The aerodynamic method was used to gap‐fill BREB system measurements, and those flux estimates were compared with estimates produced separately by the aerodynamic and EC methods. All methods found greater emissions over the biotechnology waste application. The aerodynamic method CO2 flux estimates were considerably greater than both the EC and a combined BREB‐aerodynamic approach. During the day, the EC and BREB methods agree. At night, the aerodynamic approach detects and accounts for buildup of CO2 at the surface during stable periods. The BREB systems combined with aerodynamic approaches provide alternate methods to EC in examining micrometeorological properties near the surface

Direct antioxidant properties of methotrexate: Inhibition of malondialdehyde-acetaldehyde-protein adduct formation and superoxide scavenging.

Methotrexate (MTX) is an immunosuppressant commonly used for the treatment of autoimmune diseases. Recent observations have shown that patients treated with MTX also exhibit a reduced risk for the development of cardiovascular disease (CVD). Although MTX reduces systemic inflammation and tissue damage, the mechanisms by which MTX exerts these beneficial effects are not entirely known. We have previously demonstrated that protein adducts formed by the interaction of malondialdehyde (MDA) and acetaldehyde (AA), known as MAA-protein adducts, are present in diseased tissues of individuals with rheumatoid arthritis (RA) or CVD. In previously reported studies, MAA-adducts were shown to be highly immunogenic, supporting the concept that MAA-adducts not only serve as markers of oxidative stress but may have a direct role in the pathogenesis of inflammatory diseases. Because MAA-adducts are commonly detected in diseased tissues and are proposed to mitigate disease progression in both RA and CVD, we tested the hypothesis that MTX inhibits the generation of MAA-protein adducts by scavenging reactive oxygen species. Using a cell free system, we found that MTX reduces MAA-adduct formation by approximately 6-fold, and scavenges free radicals produced during MAA-adduct formation. Further investigation revealed that MTX directly scavenges superoxide, but not hydrogen peroxide. Additionally, using the Nrf2/ARE luciferase reporter cell line, which responds to intracellular redox changes, we observed that MTX inhibits the activation of Nrf2 in cells treated with MDA and AA. These studies define previously unrecognized mechanisms by which MTX can reduce inflammation and subsequent tissue damage, namely, scavenging free radicals, reducing oxidative stress, and inhibiting MAA-adduct formation

Novel Antioxidant Properties of Doxycycline

Doxycycline (DOX), a derivative of tetracycline, is a broad-spectrum antibiotic that exhibits a number of therapeutic activities in addition to its antibacterial properties. For example, DOX has been used in the management of a number of diseases characterized by chronic inflammation. One potential mechanism by which DOX inhibits the progression of these diseases is by reducing oxidative stress, thereby inhibiting subsequent lipid peroxidation and inflammatory responses. Herein, we tested the hypothesis that DOX directly scavenges reactive oxygen species (ROS) and inhibits the formation of redox-mediated malondialdehyde-acetaldehyde (MAA) protein adducts. Using a cell-free system, we demonstrated that DOX scavenged reactive oxygen species (ROS) produced during the formation of MAA-adducts and inhibits the formation of MAA-protein adducts. To determine whether DOX scavenges specific ROS, we examined the ability of DOX to directly scavenge superoxide and hydrogen peroxide. Using electron paramagnetic resonance (EPR) spectroscopy, we found that DOX directly scavenged superoxide, but not hydrogen peroxide. Additionally, we found that DOX inhibits MAA-induced activation of Nrf2, a redox-sensitive transcription factor. Together, these findings demonstrate the under-recognized direct antioxidant property of DOX that may help to explain its therapeutic potential in the treatment of conditions characterized by chronic inflammation and increased oxidative stress