Carbon sequestration in peatland: patterns and mechanisms of response to climate change

The response of peatlands to changes in the climatic water budget is crucial to predicting potential feedbacks on the global carbon (C) cycle. To gain insight on the patterns and mechanisms of response, we linked a model of peat accumulation to a model of peatland hydrology, then applied these models to empirical data spanning the past 5000 years for the large mire Store Mosse in southern Sweden. We estimated parameters for C sequestration and height growth by fitting the peat accumulation model to two age profiles. Then, we used independent reconstruction of climate wetness and model reconstruction of bog height to examine changes in peatland hydrology. Reconstructions of C sequestration showed two distinct patterns of behaviour: abrupt increases associated with major transitions in vegetation and dominant Sphagnum species (fuscum, rubellum-fuscum and magellanicum stages), and gradual decreases associated with increasing humification of newly formed peat. Carbon sequestration rate ranged from a minimum of 14 to a maximum of 72 g m(-2) yr(-1), with the most rapid changes occurring in the past 1000 years. Vegetation transitions were associated with periods of increasing climate wetness during which the hydrological requirement for increased seepage loss was met by rise of the water table closer to the peatland surface, with the indirect result of enhancing peat formation. Gradual decline in C sequestration within each vegetation stage resulted from enhanced litter decay losses from the near-surface layer. In the first two vegetation stages, peatland development (i.e., increasing surface gradient) and decreasing climate wetness drove a gradual increase in thickness of the unsaturated, near-surface layer, reducing seepage water loss and peat formation. In the most recent vegetation stage, the surface diverged into a mosaic of wet and dry microsites. Despite a steady increase in climate wetness, C sequestration declined rapidly. The complexity of response to climate change cautions against use of past rates to estimate current or to predict future rates of peatland C sequestration. Understanding interactions among hydrology, surface structure and peat formation are essential to predicting potential feedback on the global C cycle

Forages for cattle : new methods of determining energy content asnd evaluating heat damage

"The crude fiber method of feed analysis has been used for more than 100 years. Although this method was an important first attempt at determining the energy content of feeds, it has a number of shortcomings."--First page.Ronald L. Belyea and Rex E. Ricketts (Department of Dairy Science College of Agriculture)Revised 11/86/8

Whole soybeans for dairy cattle (1987)

Whole soybeans (WSB) can be used in dairy cow rations; they are palatable and have excellent feed value. WSB have lower protein content than soybean meal but because of higher fat, have higher net energy contentNew 3/87/6M

Whole soybeans for dairy cattle (1993)

Whole soybeans (WSB) can be used in dairy cow rations; they are palatable and have excellent feed value. WSB have lower protein content than soybean meal, but because of higher fat, have higher net energy content.Reviewed October 1993 -- Extension website

The role of hydrological transience in peatland pattern formation

The sloping flanks of peatlands are commonly patterned with non-random, contour-parallel stripes of distinct microhabitats such as hummocks, lawns and hollows. Patterning seems to be governed by feedbacks among peatland hydrological processes, plant micro-succession, plant litter production and peat decomposition. An improved understanding of peatland patterning may provide important insights into broader aspects of the long-term development of peatlands and their likely response to future climate change

Forages for cattle -- new methods of determining energy content and evaluating heat damage

Ronald L. Belyea and Rex E. Ricketts (Department of Dairy Science, College of Agriculture)New 2/82/8

Using a microwave oven to determine moisture in forages (1993)

Harvesting and storing forage crops at the proper moisture is necessary to minimize forage losses and to maintain maximum nutritional value. But it is difficult to determine the moisture concentration of forage crops prior to ensiling or baling. This publication will discuss the method of using a microwave oven to determine moisture in forages.Barry Steevens, Ron Belyea, Richard Crawford (Department of Animal Sciences)Reviewed October 1993 -- Extension website

The Effects of Bovine Growth Hormone (bGH) on Dairy Farm Profitability by Type of Government Program

Administration of Bovine Growth Hormone (bGH) to dairy cows has been shown to increase milk production. Injecting milk cows with bGH results in increased milk production per cow from 10 to 40 percent (Kalter et al.). This response is rapid and continues as long as treatment is given. Presently, the injection is daily, but research is ongoing to develop implants to eliminate this tedious and laborious approach. Some feel that bGH will be available for commercial use within two or three years. It is now in the testing stage for Food and Drug Administration (FDA) approval

Forages for cattle : new methods of determining energy content and evaluating heat damage (1993)

The crude fiber method of feed analysis has been used for more than 100 years. Although this method was an important first attempt at determining the energy content of feeds, it has a number of shortcomings. A new analytical approach for estimating energy content of forages was developed by Van Soest in the 1960s at the USDA Beltsville Nutritional Research Facility. These detergent fiber analyses give more accurate estimates of forage energy values and now are used for forage analysis.Reviewed October 1993 -- Extension website

Modeling the flow of digesta through the ruminant reticulorumen

Abstract only availableRuminants possess a specialized gastrointestinal (GI) tract that enables them to efficiently digest fibrous feeds. The first stomach compartment of the ruminant GI tract, the reticulorumen (RR), is the site of most fiber digestion due to the presence of cellulolytic microorganisms in conjunction with selective retention of feed particles; undigested fibrous feed particles are selectively retained and fermented by cellulolytic microorganisms in the RR until certain digestive processes are completed, enabling the particles to pass. Selective retention and the overall process of digesta flow in the RR affect feed digestibility, feed intake, and microbial efficiency—all important animal performance parameters in ruminant production. It is imperative to model digesta flow in the RR to better predict these animal performance parameters for use in ruminant production systems. Mathematical models have indeed been developed to describe the flow of digesta in the RR, typically with the RR represented as one or more mathematical compartments with flow between compartments defined by kinetic rate variables or constants. Mathematical models developed to the present use either fractional rate constants or rate variables based on the gamma distribution. The Yule distribution has also been suggested for modeling RR digesta flow kinetics, but its development has been cursory. It remains unseen what, if any, benefits may arise from applying the Yule distribution to describe the kinetics of RR digesta. In this study, a model incorporating the Yule distribution is fully developed. Physiological justification for using the Yule distribution is also provided on the basis of selective retention. A comparison between the model developed herein and a previously published model using the gamma distribution reveals that both models give similar mathematical results under certain cases. Still, it is suggested that the physiological relevance of the model treated here may make it superior. Animal feeding trials are currently being conducted to validate the structure of model. Additionally, mathematical models are being developed to describe small and large intestinal flow in ruminant and non-ruminant species, thereby expanding this modeling effort to include most of the GI tract.Life Sciences Undergraduate Research Opportunity Progra