the influence of salinity on the different polyamine fractions (free, conjugated, and bound) was compared in a natrophilic halophyte (beta vulgaris l. cv. ic) and a salt sensitive glycophyte (nicotiana rustica l. cv. basmas). low-level salinity (25 mm nacl) and high salinity (150 and 50 mm nacl for sugar beet and tobacco, respectively) were supplied in hydroponics. under low salinity shoot dry ...

Recent research has dramatically advanced our understanding of soil organic matter chemistry and the role of N in some organic matter transformations, but the effects of N deposition on soil C dynamics remain difficult to anticipate. We examined soil organic matter chemistry and enzyme kinetics in three size fractions ([250 lm, 63–250 lm, and \63 lm) following 6 years of simulated atmospheric N...

estimation of optimum fertilizer rates is needed because of growing economic and environmental concerns. optimum fertilizer rates can be determined by fitting statistical models to yield data collected from n fertilizer experiments. the main goal of this research was to compare and evaluate quadratic, square root, mitscherlich, rectangular hyperbola, linear plus plateau and quadratic plus plate...

this paper is concerned with asphaltene deposition in fluid flowing through pipelines. brownian diffusion and drag, gravitational, thermophoresis, buoyancy, and shear removal are considered as possible mechanisms in the asphaltene deposition process. the thermo-physical properties of the fluid were obtained from iranian oil fields. a model was used in the pipeline deposition modeling to predict...

We evaluated foliar and forest floor chemistry across a gradient of N deposition in the Northeast at 11 red spruce (Picea rubens Sarg.) sites in 1987/1988 and foliar and forest floor chemistry and basal area growth at six paired spruce and deciduous sites in 1999. The six red spruce plots were a subset of the original 1987/1988 spruce sites. In 1999, we observed a significant correlation betwee...

Title of Document: EFFECTS OF NITROGEN AND CALCIUM ON PHOTOSYNTHESIS AND METABOLIC ACTIVITY IN ACER SACCHARUM IN THE CATSKILL MOUNTAINS. Shawna Joy Behling Directed By: Associate Professor Dr. Joseph Sullivan Plant Sciences and Landscape Architecture The Catskill Mountains in southern New York have received some of the most acidic rainfall in the country for the past 50 years. Acid deposition o...

The trace metal (TM: Cd, Cu, Ni, Pb and Zn) budget (stocks and annual fluxes) was evaluated in a forest stand (silver fir, Abies alba Miller) in north-eastern France. Trace metal concentrations were measured in different tree compartments in order to assess TM partitioning and dynamics in the trees. Inputs included bulk deposition, estimated dry deposition and weathering. Outputs were leaching ...

Much of the agricultural land in the Central Hills area of the Sichuan Basin is at risk from soil erosion by water. An investigation of rates and patterns of soil erosion on agricultural land near Yanting was undertaken using the caesium-137 technique. Erosion of the upper parts of sloping fields was found to be severe, with rates of the order of 20 to 50 t ha" year". However, infield depositio...

Ozone/TEOS thermal chemical vapor deposition ~CVD! has been investigated for SiO2 deposition on Si, using a cold-wall research reactor equipped to determine the effects of precursor concentration, deposition temperature ~300–500 °C!, and pressure ~30–200 Torr! on deposition rates, etch rates, and step coverage in the regime of subatmospheric CVD ~SACVD!. Deposition rates first increase with sub...