LXXIV.?On myrticolorin, the yellow dye material of Eucalyptus leaves

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SOIL QUALITY ATTRIBUTE TIME PATHS: OPTIMAL LEVELS AND VALUES

We develop a dynamic soil quality model to evaluate optimal cropping systems in the northern Great Plains. Modeling soil quality attributes is feasible, and attribute model results apply to a wide range of soils. A crop production system with continuous spring wheat and direct planting is the most profitable system. This system has low soil erosion and high quality attributes, indicating the benefits of increased soil quality exceed the higher maintenance costs. On-site value of additional soil organic carbon (OC) ranges from $1 to$4/ton OC/hectare/year. These values for soil OC impact the optimum tillage practice, but not the crop rotation.Crop Production/Industries,

Response of Sweet Corn to Irrigation Management

As most growers know, high sugar sweet corn has shallow roots and does not germinate well in cold soils. A clear plastic mulch improves the stand, hastens maturity in cool springs, and improves marketability. To utilize 4 ft standard clear plastic the traditional seeding method must be changed. The seeding arrangement involves twin rows, 18 in. apart, with in-row spacing at 12 in. and with 2 plants per position. Center to center of the beds varies from 5.5 to 7 ft. Plant population is higher, approximately 29,000 plants per acre. Irrigation is usually required for high quality yield. Trickle irrigation tubing placed down the center of each bed or 9 in. from each row would allow timely water application based on crop demand. Our objective for the last several years has been to evaluate irrigation scheduling models for sweet corn planted in twin rows on clear plastic mulch

Theoretical Transmission Spectra During Extrasolar Giant Planet Transits

The recent transit observation of HD 209458 b - an extrasolar planet orbiting a sun-like star - confirmed that it is a gas giant and determined that its orbital inclination is 85 degrees. This inclination makes possible investigations of the planet atmosphere. In this paper we discuss the planet transmission spectra during a transit. The basic tenet of the method is that the planet atmosphere absorption features will be superimposed on the stellar flux as the stellar flux passes through the planet atmosphere above the limb. The ratio of the planet's transparent atmosphere area to the star area is small, approximately 10^{-3} to 10^{-4}; for this method to work very strong planet spectral features are necessary. We use our models of close-in extrasolar giant planets to estimate promising absorption signatures: the alkali metal lines, in particular the Na I and K I resonance doublets, and the He I $2^3S$ - $2^3P$ triplet line at 1083.0 nm. If successful, observations will constrain the line-of-sight temperature, pressure, and density. The most important point is that observations will constrain the cloud depth, which in turn will distinguish between different atmosphere models. We also discuss the potential of this method for EGPs at different orbital distances and orbiting non-solar-type stars.Comment: revised to agree with accepted paper, ApJ, in press. 12 page