Forage Quality and Performance of Tall Fescue Hay Amended with Broiler Litter and Commercial Fertilizer

Broiler chickens are a leading agricultural commodity in Tennessee. Many broiler operations are located in eastern and middle Tennessee where a common land use is tall fescue (Festuca arundinacea Schreb.) hay and pasture, for cow-calf and dairy operations. Litter from broiler operations is land applied on fescue at rates that often exceed the recommended phosphorus (P) and potassium (K) rates. Surveys of forage quality conducted by the University of Tennessee Extension in 2001 found that many forages across the state had higher than recommended K and sulfur levels and were deficient in copper (Cu) and other nutrients. In spring 2004 a two-year study initiated at the Research and Education Center at Greeneville, TN evaluated the performance and forage quality of tall fescue hay amended annually with 3 rates of broiler litter (2.3, 6.8, and 11.3 Mg/ha) and 2 commercial fertilizer rates (a recommended rate, 114-30-28 kg/ha of NPK; and a commonly used rate 65-29-54 kg/ha of NPK). The study was conducted on a Dewey silt clay loam (fine, kaolinitic, thermic, Typic Paleudult), severely eroded soil (12 to 25 percent slope). Mehlich I soil analysis indicated increased phosphorus (P) and increased zinc (Zn) levels after application and harvest. All plots were harvested in May 2004, September 2004, and May 2005. Forage analysis was conducted to determine the nutrient content in the fescue. Dry matter yields of higher quality forage were obtained using high litter rates (11.3 Mg/ha) and the recommended fertilizer rate. In 2004 and 2005, Cu, Na, and Zn levels were below and (S) sulfur levels above National Resource Council (NRC) recommendations for beef cattle, while Ca and Mg were above recommendations. Using high litter applications (11.3 Mg/ha) resulted in K levels at or above maximum tolerable concentration (30 g/kg) critical for beef cattle in May 2004 and 2005

Advances and perspectives on the ecology and management of Castanea species

Species of chestnut (Castanea spp.) are naturally widespread throughout temperate forests of the northern hemisphere in Asia, Europe, and North America. Populations have been naturalized outside of species’ native ranges in Europe, North America, South America and Oceania. The wide diffusion on a planetary level over tens of millions of years has resulted in high genetic variability within the genus and spe- cies adaptations to disparate environmental conditions (Dane et al., 2003; Mellano et al., 2012; Krebs et al., 2019). Perhaps more than many other tree species, the history of chestnut has been closely linked to human civilizations who utilized chestnut as an agricultural and forest resource over millennia. Chestnut species have had important cultural significance for Indigenous communities, although much Traditional Ecological Knowledge has been lost (Barnhill-Dilling and Delborne, 2019), and chestnut species have been subjected to challenges of the contemporary Anthropocene, from globalization to climate change. Al- terations to disturbance regimes, particularly related to drought and fire, and the introduction of nonnative pests and pathogens, have reduced genetic diversity and population densities, particularly for species in North America, Europe, and western Asia (Mellano et al., 2012; Dalgleish et al., 2016). Forest management practices, genomic tools, tree breeding, and prediction models have been developed and tested to meet these challenges (Jacobs et al., 2013; Fernandes et al., 2022). Most strategies, however, are underdeveloped and species spe- cific, including for American chestnut (Burnham et al., 1986; Ana- gnostakis, 2012; Fei et al., 2012) and sweet chestnut (Conedera et al., 2016; Manetti et al., 2019; Marcolin et al., 2020; Patrício et al., 2020). A global perspective for chestnut sustainability, conservation, and man- agement has largely been missing in the literature, excluding pro- ceedings from International Chestnut Symposia (e.g., Double and MacDonald, 2014).info:eu-repo/semantics/publishedVersio

A silvicultural synthesis of sweet (Castanea sativa) and American (C. dentata) chestnuts

Sweet chestnut (Castanea sativa) and American chestnut (C. dentata) have been explicitly linked to ancient, historical, and contemporary cultures while enhancing ecological services in forests in which they occur. Threats that currently face these chestnut species are unprecedented and additive, including global climate change, nonnative pest and pathogen species, land use changes, and lack of scientific knowledge and technologies. In this paper, we provide a synthesis of traditional and novel silvicultural systems for chestnut, focusing on these two important species. We frame the discussion within the context of the species’ cultural and ecological significances, scientific knowledge bases, and associated knowledge gaps. Sweet and American chestnuts require divergent strategies to sustain their conservation values due to differing cultural and ecological landscapes and biological stressors. Both species share the need to conduct active forest management to maintain or restore populations in native or naturalized habitats. Even-aged management is the preferred regeneration method for both species. Coppicing that is commonly implemented for sweet chestnut can provide a potential strategy for American chestnut once disease-resistant material becomes widely available. Blight caused by Cryphonectria parasitica may limit long rotation timber production of American chestnut, even for resistant material, making short-rotation systems a more attractive management option. Advanced artificial regeneration and breeding strategies have been developed for American chestnut but are largely underdeveloped for sweet chestnut. High forests of sweet chestnut can play an important role in new single or mixed species plantations, naturalized stands, or in naturally regenerated stands for production of medium-large dimension timber. American chestnut will likely be managed as a minor to moderate component of mixed species forests to achieve ecological restoration goals. A close-to-nature silvicultural approach has not been tested for either species and may be difficult to implement due to the threats from changing climate conditions and nonnative pathogens. Traditional and emerging markets of sweet chestnut, such as biomass or carbon markets, may help inform future opportunities around American chestnut for tribal and rural communities. Climate change and other threats call for synergistic partnerships and knowledge sharing to maintain or restore sweet and American chestnuts as part of the global ecosystem.This research was in part funded by: Chilean Ministry of Agriculture (Development and contributions for the use of forest and fruit species of high value for Chile, INFOR); ANID BASAL FB210015 (CENAMAD); the United States Department of Agriculture Forest Service; the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC), CIMO (UIDB/00690/2020 and UIDP/00690/2020); and SusTEC (LA/P/0007/2020).info:eu-repo/semantics/publishedVersio

Stand dynamics of an oak woodland forest and effects of a restoration treatment on forest health

a b s t r a c t Woodland restoration has been conducted in many countries, primarily in Mediterranean regions, but has only recently been attempted on publically and privately owned lands in the eastern United States. We reconstructed historical stand dynamics and tested the immediate effects of an oak (Quercus) woodland restoration treatment on forest health, inferred from tree-ring widths (TRW). The stands were upland white oak (Q. alba) and chestnut oak (Q. prinus) dominated and were located on the Cumberland Plateau of eastern Kentucky, USA. The stands regenerated primarily under a severe disturbance regime concurrent with peak industrial logging approximately 100 years ago. A relatively high percentage of trees (38 percent) recruited under large canopy gaps or clearings, indicative of a severe disturbance; however, gap-phase dynamics was also an important process in oak recruitment to the canopy. Primarily small (<31 cm DBH) and young (<110 years old) trees were removed during the restoration treatment, and mean DBH of residual trees was 13 cm larger than harvested trees. Residual trees were 22 years older than harvested trees, but this difference was not significant. The largest and oldest trees represented important legacy trees that could provide desirable forest biodiversity attributes. Residual trees had larger TRWs than harvested trees, beginning in the 1930s, and these differences increased over time. Residual trees also had larger TRW during two recent drought events (1986 and 1999), but recovery following drought was similar between residual and harvested trees. Managers can use well established silvicultural techniques to obtain desired stand structural conditions, while selecting healthy trees that have better response to stress factors such as drought. The oak woodland restoration treatment may help to maintain residual overstory trees until oak regeneration can be recruited to provide sustainability towards the next generation. Published by Elsevier B.V

The formation of the first galaxies and the transition to low-mass star formation

The formation of the first galaxies at redshifts z ~ 10-15 signaled the transition from the simple initial state of the universe to one of ever increasing complexity. We here review recent progress in understanding their assembly process with numerical simulations, starting with cosmological initial conditions and modelling the detailed physics of star formation. In this context we emphasize the importance and influence of selecting appropriate initial conditions for the star formation process. We revisit the notion of a critical metallicity resulting in the transition from primordial to present-day initial mass functions and highlight its dependence on additional cooling mechanisms and the exact initial conditions. We also review recent work on the ability of dust cooling to provide the transition to present-day low-mass star formation. In particular, we highlight the extreme conditions under which this transition mechanism occurs, with violent fragmentation in dense gas resulting in tightly packed clusters.Comment: 16 pages, 7 figures, appeared in the conference proceedings for IAU Symposium 255: Low-Metallicity Star Formation: From the First Stars to Dwarf Galaxies, a high resolution version (highly recommended) can be found at http://www.ita.uni-heidelberg.de/~tgreif/files/greif08.pd

Open questions in the study of population III star formation

The first stars were key drivers of early cosmic evolution. We review the main physical elements of the current consensus view, positing that the first stars were predominantly very massive. We continue with a discussion of important open questions that confront the standard model. Among them are uncertainties in the atomic and molecular physics of the hydrogen and helium gas, the multiplicity of stars that form in minihalos, and the possible existence of two separate modes of metal-free star formation.Comment: 15 pages, 2 figures. To appear in the conference proceedings for IAU Symposium 255: Low-Metallicity Star Formation: From the First Stars to Dwarf Galaxie

Trichloroethylene Exposure during Cardiac Valvuloseptal Morphogenesis Alters Cushion Formation and Cardiac Hemodynamics in the Avian Embryo

It is controversial whether trichloroethylene (TCE) is a cardiac teratogen. We exposed chick embryos to 0, 0.4, 8, or 400 ppb TCE/egg during the period of cardiac valvuloseptal morphogenesis (2–3.3 days’ incubation). Embryo survival, valvuloseptal cellularity, and cardiac hemodynamics were evaluated at times thereafter. TCE at 8 and 400 ppb/egg reduced embryo survival to day 6.25 incubation by 40–50%. At day 4.25, increased proliferation and hypercellularity were observed within the atrioventricular and outflow tract primordia after 8 and 400 ppb TCE. Doppler ultrasound revealed that the dorsal aortic and atrioventricular blood flows were reduced by 23% and 30%, respectively, after exposure to 8 ppb TCE. Equimolar trichloroacetic acid (TCA) was more potent than TCE with respect to increasing mortality and causing valvuloseptal hypercellularity. These results independently confirm that TCE disrupts cardiac development of the chick embryo and identifies valvuloseptal development as a period of sensitivity. The hypercellular valvuloseptal profile is consistent with valvuloseptal heart defects associated with TCE exposure. This is the first report that TCA is a cardioteratogen for the chick and the first report that TCE exposure depresses cardiac function. Valvuloseptal hypercellularity may narrow the cardiac orifices, which reduces blood flow through the heart, thereby compromising cardiac output and contributing to increased mortality. The altered valvuloseptal formation and reduced hemodynamics seen here are consistent with such an outcome. Notably, these effects were observed at a TCE exposure (8 ppb) that is only slightly higher than the U.S. Environmental Protection Agency maximum containment level for drinking water (5 ppb)

Varied Response of Western Pacific Hydrology to Climate Forcings over the Last Glacial Period

Atmospheric deep convection in the west Pacific plays a key role in the global heat and moisture budgets, yet its response to orbital and abrupt climate change events is poorly resolved. Here, we present four absolutely dated, overlapping stalagmite oxygen isotopic records from northern Borneo that span most of the last glacial cycle. The records suggest that northern Borneo’s hydroclimate shifted in phase with precessional forcing but was only weakly affected by glacial-interglacial changes in global climate boundary conditions. Regional convection likely decreased during Heinrich events, but other Northern Hemisphere abrupt climate change events are notably absent. The new records suggest that the deep tropical Pacific hydroclimate variability may have played an important role in shaping the global response to the largest abrupt climate change events

Ancient convergent losses of Paraoxonase 1 yield potential risks for modern marine mammals

Mammals diversified by colonizing drastically different environments, with each transition yielding numerous molecular changes, including losses of protein function. Though not initially deleterious, these losses could subsequently carry deleterious pleiotropic consequences. We have used phylogenetic methods to identify convergent functional losses across independent marine mammal lineages. In one extreme case, Paraoxonase 1 (PON1) accrued lesions in all marine lineages, while remaining intact in all terrestrial mammals. These lesions coincide with PON1 enzymatic activity loss in marine species’ blood plasma. This convergent loss is likely explained by parallel shifts in marine ancestors’ lipid metabolism and/or bloodstream oxidative environment affecting PON1’s role in fatty acid oxidation. PON1 loss also eliminates marine mammals’ main defense against neurotoxicity from specific man-made organophosphorus compounds, implying potential risks in modern environment

Ancient convergent losses of Paraoxonase 1 yield potential risks for modern marine mammals

Mammals diversified by colonizing drastically different environments, with each transition yielding numerous molecular changes, including losses of protein function. Though not initially deleterious, these losses could subsequently carry deleterious pleiotropic consequences. We have used phylogenetic methods to identify convergent functional losses across independent marine mammal lineages. In one extreme case, Paraoxonase 1 (PON1) accrued lesions in all marine lineages, while remaining intact in all terrestrial mammals. These lesions coincide with PON1 enzymatic activity loss in marine species’ blood plasma. This convergent loss is likely explained by parallel shifts in marine ancestors’ lipid metabolism and/or bloodstream oxidative environment affecting PON1’s role in fatty acid oxidation. PON1 loss also eliminates marine mammals’ main defense against neurotoxicity from specific man-made organophosphorus compounds, implying potential risks in modern environment