Conserved Forage (Silage and Hay): Progress and Priorities

Forage conservation permits a better supply of quality feed when forage production is low. While haymaking and ensiling have been practiced for generations, research is still needed to 1) understand the processes affecting quality during harvesting and storage and 2) develop practical means to minimize losses and enhance quality. Several trends in harvesting forages for silage are notable. Kernel processing of maize, once confined to Europe, has become popular in North America. Self-propelled forage harvesters have a larger share of the market due to more contract harvesting and larger farms. Larger harvesters, rakes and mergers help improve productivity and forage quality. Finally, farmers are increasing cutting length to meet the fiber needs of high-producing dairy cattle. These latter two trends make good silo management more critical. The number of silo types has continued to increase. Pressed bag and wrapped bale silages are important recent developments. These newer types have made it easier to segregate silages by quality and allow small farms to make high quality silage. However, disposal of the larger quantities of plastic is a growing issue. Alternatives such as edible or biodegradable films would be welcome for all silo types, reducing labor and environmental concerns. With wrapped bales, spoilage and listeria contamination are more common because of the large surface to volume ratio. Enhanced methods to control spoilage and pathogen development are needed. With most crops considerable breakdown of true protein occurs during ensiling, subsequently decreasing nitrogen utilization efficiency in ruminants. The polyphenol oxidases in red clover and the tannins in some legumes reduce protein loss during ensiling. These mechanisms may be useful in developing new silage additives or plant varieties. Additives can enhance silage quality. Inoculants are the most common. Improved inoculants aimed at increasing aerobic stability are beginning to be marketed, but their overall success is uncertain. Enzymes to degrade plant cell walls, providing sugar for fermentation and making the silage more digestible, have not fulfilled their promise but do have potential. Acids and sugars have been declining in use but still are important in certain ensiling situations. Three types of balers are used to package dry hay: small square (SSB), large round (LRB) and large square balers (LSB). The SSB is declining importance in developed countries because of labor constraints but remains viable in developing countries where farm labor is still plentiful. The LRB is the dominant baler worldwide because of its productivity and low ownership and operating costs. High productivity and a package ideally suited for shipping has promoted the continuing growth of the LSB. Hay producers struggle with getting crops dry enough (\u3c 20% moisture) to prevent excess storage losses due to biological activity. This is especially important as bale density increases. Typical bale densities are about 130, 190 and 240 kg/m3 for SSB, LRB and LSB, respectively. In humid climates, forage researchers and producers are investigating intensive conditioning systems to improve field drying rates, utilizing preservatives like propionic acid, and developing bale ventilation and drying systems all in the attempt to improve dry hay quality. In arid regions, producers only bale after dew accumulation has softened brittle plant tissue to reduce leaf loss. Systems are under development that will soften plant tissue at the baler by applying a fine water mist. Larger livestock farms and increased development of markets for commercial hay will push demand for greater productivity and better bale quality

Categorizing how students use collaborative technologies in a globally distributed project.

Possibilities for collaboration in globally distributed projects have radically changed with the introduction of new Collaborative Technologies (CTs) in the Web 2.0 era. The use of such technologies in the context of students collaborating in a globally distributed project is little explored in research. A better understanding would provide opportunities for improving the collaboration, and more importantly is that a better understanding would improve the possibility of scaffolding, and student learning in general. In this paper we present results from a study of students' use of CTs in a globally distributed project with a focus on the challenges encountered in trying to collaborate using this technology. The study is focused on a few aspects of how a combination of CTs could be utilized and issues associated with their set up and adaption for use. We discuss potential reasons for the observed patterns of technology use and how they influenced the collaboration environment around a globally distributed student project

Categorizing how students use collaborative technologies in a globally distributed project.

Possibilities for collaboration in globally distributed projects have radically changed with the introduction of new Collaborative Technologies (CTs) in the Web 2.0 era. The use of such technologies in the context of students collaborating in a globally distributed project is little explored in research. A better understanding would provide opportunities for improving the collaboration, and more importantly is that a better understanding would improve the possibility of scaffolding, and student learning in general. In this paper we present results from a study of students' use of CTs in a globally distributed project with a focus on the challenges encountered in trying to collaborate using this technology. The study is focused on a few aspects of how a combination of CTs could be utilized and issues associated with their set up and adaption for use. We discuss potential reasons for the observed patterns of technology use and how they influenced the collaboration environment around a globally distributed student project

Grasses and Legumes for Cellulosic Bioenergy

Human life has depended on renewable sources of bioenergy for many thousands of years, since the time humans fi rst learned to control fi re and utilize wood as the earliest source of bioenergy. The exploitation of forage crops constituted the next major technological breakthrough in renewable bioenergy, when our ancestors began to domesticate livestock about 6000 years ago. Horses, cattle, oxen, water buffalo, and camels have long been used as sources of mechanical and chemical energy. They perform tillage for crop production, provide leverage to collect and transport construction materials, supply transportation for trade and migratory routes, and create manure that is used to cook meals and heat homes. Forage crops—many of which form the basis of Grass: The 1948 Yearbook of Agriculture (Stefferud, 1948), as well as the other chapters of this volume—have composed the principal or only diet of these draft animals since the dawn of agriculture

Harvest and storage of two perennial grasses as biomass feedstocks

ABSTRACT. Some perennial grasses, such as reed canarygrass (RCG) n North America, the main feedstock for fuel ethanol is currently corn grain. New enzyme hydrolysis and fermentation technologies are being developed to produce ethanol from cellulosic biomass such as grasses, straw, and wood. The energy balance for these materials has the potential to be much more favorable than with corn grain One production variable that needs to be considered with perennial grasses to be used as biomass feedstocks is cutting frequency. Since high forage quality for livestock production is not required, it may be more economical to harvest perennial grasses once per year

Effect of Torrefaction on Water Vapor Adsorption Properties and Resistance to Microbial Degradation of Corn Stover

The equilibrium moisture content (EMC) of biomass affects transportation, storage, downstream feedstock processing, and the overall economy of biorenewables production. Torrefaction is a thermochemical process conducted in the temperature regime between 200 and 300 °C under an inert atmosphere that, among other benefits, aims to reduce the innate hydrophilicity and susceptibility to microbial degradation of biomass. The objective of this study was to examine water sorption properties of torrefied corn stover. The EMC of raw corn stover, along with corn stover thermally pretreated at three temperatures, was measured using the static gravimetric method at equilibrium relative humidity (ERH) and temperatures ranging from 10 to 98% and from 10 to 40 °C, respectively. Five isotherms were fitted to the experimental data to obtain the prediction equation that best describes the relationship between the ERH and the EMC of lignocellulosic biomass. Microbial degradation of the samples was tested at 97% ERH and 30 °C. Fiber analyses were conducted on all samples. In general, torrefied biomass showed an EMC lower than that of raw biomass, which implied an increase in hydrophobicity. The modified Oswin model performed best in describing the correlation between ERH and EMC. Corn stover torrefied at 250 and 300 °C had negligible dry matter mass loss due to microbial degradation. Fiber analysis showed a significant decrease in hemicellulose content with the increase in pretreatment temperature, which might be the reason for the hydrophobic nature of the torrefied biomass. The outcomes of this work can be used for torrefaction process optimization, and decision-making regarding raw and torrefied biomass storage and downstream processing

A Portable Instrumentation System for Measuring Draft and Speed

ABSTRACT A portable instrumentation system was developed to measure draft and speed when using either pull type or three point hitch mounted implements. The parameters measured were horizontal and vertical draft, true ground speed and drive wheel speed. The system utilized strain gage load cells with excitation provided by a compact, portable datalogger. Measurements were taken and stored using the dataloger, then transferred via magnetic cassette tape to a microcomputer for further processing. The force dynamometer was designed for tractors up to 80 kW with a maximum draft capacity of 60 kN. Calibration procedures, results from the use of the system and actual tillage energy requirements are presented

Wet Fractionation for Improved Utilization of Alfalfa Leaves

ABSTRACT. Utilization of alfalfa could be greatly improved if the protein-rich leave