Grasslands, Communicating the Benefits

The multiple benefits of perennial agriculture , including forages and grasslands, for building soil quality, protection of natural resources, enhancement of biodiversity and wildlife, are well known to us, but little understood by the public. This is not a situation where “more education” would necessarily increase recognition. Rather, we must build in the public a desire for the enhancement of green space, clean water and air, and diverse landscapes that multiple purpose agriculture can bring. We seek such environments intuitively and now that much of the world’s people are “trapped” in urban settings of steel and concrete, this desire is even more apparent. Yet other forces continually work against using agriculture for such uses. Economic motives are at the base of the conflict. Grasslands seldom produce recognizable returns. It is important for grassland scientists to bring to the public forum the benefits of their unique approach, even while the agricultural world seems to be moving toward a grain-based economy. Such recognition is necessary if public support of conservation incentives are to become a part of agriculture. Rotational grazing offers one way around the economic issue, and will be discussed in detail. Other economic approaches involve government leasing and government recognition of environmental benefits (Conservation Reserve Program). A concept gaining support involves carbon trading. This is payment to the land owner by public or private entities for conservation practices that sequester carbon, thereby reducing the carbon dioxide load in the atmosphere and slowing global climate change. Carbon trading could ultimately be endorsed in the Kyoto treaty, making carbon sequestration a part of national policies and a new way to support multifuctional agriculture. The paper will discuss pros and cons of several management options that will require the use of perennial crops, grasslands in particular. Ways are also discussed to engage the public in the decision making process. The bottom line, however, is that in some way or the other grasslands systems often must be subsidized in the United States

Chapter 1. The Nitrogen Cycle, Historical Perspective, and Current and Potential Future Concerns

Nitrogen (N) along with carbon and oxygen is the most complex and crucial of the elements essential for life. Supplementing grain and grass forage crops with organic and inorganic N fertilizers has long been recognized as a key to improving crop yields and economic returns. Globally. N fertilizer is largely used for cereal grain production and accounts for an estimated 40(1r of the increase in per capita food production in the past 50 years (Mosier et al.. 200 I). Smil (200 I) estimates that N fertilizer supplies up to 40% of the world\u27s dietary protein and dependence on N from the Haber-Bosch process will increase in the future. Nitrogen compounds also have been recognized for their many potential adverse impacts on the environment and health (Keeney. 2002)

The Ultraviolet Detection of Diffuse Gas in Galaxy Groups

A small survey of the UV-absorbing gas in 12 low-$z$ galaxy groups has been conducted using the Cosmic Origins Spectrograph (COS) on-board the Hubble Space Telescope (HST). Targets were selected from a large, homogeneously-selected sample of groups found in the Sloan Digital Sky Survey (SDSS). A critical selection criterion excluded sight lines that pass close ($<1.5$ virial radii) to a group galaxy, to ensure absorber association with the group as a whole. Deeper galaxy redshift observations are used both to search for closer galaxies and also to characterize these $10^{13.5}$ to $10^{14.5} M_{\odot}$ groups, the most massive of which are highly-virialized with numerous early-type galaxies (ETGs). This sample also includes two spiral-rich groups, not yet fully-virialized. At group-centric impact parameters of 0.3-2 Mpc, these $\mathrm{S/N}=15$-30 spectra detected HI absorption in 7 of 12 groups; high (OVI) and low (SiIII) ion metal lines are present in 2/3 of the absorption components. None of the three most highly-virialized, ETG-dominated groups are detected in absorption. Covering fractions $\gtrsim50$% are seen at all impact parameters probed, but do not require large filling factors despite an enormous extent. Unlike halo clouds in individual galaxies, group absorbers have radial velocities which are too low to escape the group potential well without doubt. This suggests that these groups are "closed boxes" for galactic evolution in the current epoch. Evidence is presented that the cool and warm group absorbers are not a pervasive intra-group medium (IGrM), requiring a hotter ($T\sim10^6$ to $10^7$ K) IGrM to be present to close the baryon accounting.Comment: Resubmitted to ApJS after first review; 82 pages (27 for main text, rest are Appendices and supplemental figures and tables), 47 figures, 21 table

Absolute Proper Motion of the Fornax Dwarf Spheroidal Galaxy from Photographic and HST WFPC2 Data

We have measured the absolute proper motion of the Fornax dwarf spheroidal galaxy from a combination of photographic plate material and HST WFPC2 data that provide a time baseline of up to 50 years. The extragalactic reference frame consists of 8 QSO images and 48 galaxies. The absolute proper motion is mu_alpha cos(delta) = 0.59 +-0.16 mas/yr and mu_delta = -0.15 +- 0.16 mas/yr. The corresponding orbit of Fornax is polar, with an eccentricity of 0.27, and a radial period of 4.5 Gyr. Fornax's current location is near pericenter. The direction of the motion of Fornax supports the notion that Fornax belongs to the Fornax-LeoI-LeoII-Sculptor-Sextans stream as hypothesized by Lynden-Bell (1976, 1982) and Majewski (1994). According to our orbit determination, Fornax crossed the Magellanic plane \~190 Myr ago, a time that coincides with the termination of the star-formation process in Fornax. We propose that ram-pressure stripping due to the passage of Fornax through a gaseous medium denser than the typical intragalactic medium left behind from the LMC may have caused the end of star formation in Fornax. The excess, anomalous clouds within the South Galactic pole region of the Magellanic Stream whose origin has long been debated in the literature as constituents of either the Magellanic Stream or of the extragalactic Sculptor group, are found to lie along the orbit of Fornax. We speculate that these clouds are stripped material from Fornax as the dwarf crossed the Magellanic Clouds' orbit.Comment: Accepted for publication in Astronomical Journal. The version with high resolution figures can be found at ftp://pegasus.astro.yale.edu/pub/dana/paper