Description of a dynamic closed chamber for measuring soil respiration and its comparison with other techniques

Posted in: Environment by admin on January 1, 1997 | No Comments

Soil respiration is an important component of the net carbon dioxide exchange between agricultural ecosystems and the atmosphere, and reliable estimates of soil respiration are required in carbon balance studies. Most of the field measurements of soil respiration reported in the literature have been made using alkali traps. The use of portable CO2 analysers in dynamic closed chamber
systems is recent. The introduction of this new technique requires its evaluation against existing methods in order to compare new information with older data. Nine intercomparisons between dynamic systems and alkali traps were made. Measurements of Fc,s obtained by both chambers showed a good agreement in all but two comparisons in which alkali trap measurements were lower
than the dynamic chamber by about 22%. This first report of agreement between both techniques suggests that many measurements made in the past using alkali traps may be comparable to the measurements made more recently using the dynamic chambers. Analysis of the soil temperature and CO2 concentration inside the alkali traps failed to explain why the alkali traps
occasionally underestimated the fluxes. Soil respiration measured with a dynamic closed chamber were also compared to eddycorrelation measurements. The results did not reveal any consistent bias between techniques but the scattering was large. This dispersion is likely the result of the difference between the areas measured by the two techniques.

La respiration du sol est un A

Can odours be used to reduce aggression in pigs

Posted in: Prairie Swine Centre by admin on | No Comments

Two studies were conducted with growing a

The role of the bovine practitioner in cattle welfare.

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Early weaning in swine: a behavioral review.

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Smart Ways to Control the Climate

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The lastest climate controls were displayed at Eurotier in 1996. The units are reliable, use less energy and have lower installation costs. Suppliers have heeded calls for ventilation equipment to be more cleanable and to have a system of emergency ventilation in each mechanically-ventilated house. Controls are by time, temperature or relative humidity, while the designers have aimed for limited water requirements and greater durability. In total 9 devices are summarized in the article.

Basic Options for Swine Production Enterprises

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Four basic options for swine production enterprises are described below. Characteristics of producers and swine operations that may fit each option are included.
:Operate as an independent
:Operate as an independent but “specialize”
:Operate as a contract producer
:Liquidate the operation
:Other options exist

Modelling Emissions

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For the development of odour emission model to study odour emission reduction, the chemical and physical properties of roughly 200 different gases that constitute odour from livestock production has to be better known. As for ammonia, the formation process, the diffusion and the transport in and out the livestock facility must be better understood and described. The process can be modeled by floor models, section models and airflow models. The section model is presented as being less known. This model attempt to sum up the diffusion coming from different areas or section of an animal house ( for example in a swine building with slatted floor: wet floor in animal area, back of the wet slatted floor, stored manure under the slats, wet side wall, wet and dirty animals). To be able use prediction ammonia emission models, more measurements have to be done and more knowledge of the emission processes have to be acquired.

Deep Litter Materials and the Ammonia Emissions in Fattening Pig Houses

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An appreciation of odour (as no measures are presented) showed that the sawdust bedding produced lower odour nuisance compared to straw litter and that the aerated litter also produced less odours. The pig performances showed no negative effect from the deep litter system. More work has to be done to find the optimum conditions for the good composting and nitrification and denitrification process that lower the NOx emissions as this system present advantages in reducing odour nuisance and improving the animal welfare.

Accuracy of a Windtunnel System for Measuring Ammonia Emissions after Slurry Application

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Outdoor trials have to be made to test the tunnel. The outdoor conditions have to be reproduced at the tunnel level to give significant results.

Problems arise when city meets county.

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The conflicts in Fraser Valley in British Columbia are becoming more frequent as many houses are built close to farms and the new neighbors come to the countryside for the scenery and don’t realize the nuisance associated with intensive agriculture (noise, smell, flies, dust). Approved environmental plan is needed when considering farm expansion. Concerns are directed toward manure management and also toward water supply as B.C. farmers have been blamed by Washington State for downstream contamination of the Abbotsford Aquifer.
Margaret Crowley, director of the policy development at B.C. Federation of agriculture mention that the agricultural code of practice and the province’s right-to-farm legislation will have to be considered as the municipalities have 3 years to make their bylaws conform to both. Local governments will be advised on farm practices by an agriculture advisory peer group already set up and the farmers facing complaints will be visited by this group to find solutions where needed.

Advisory peer groups is an interesting tool to help control the situation and find solutions with the farmers. Education is often the beginning of the solutions as the farmers and local governments have more tools and understanding in addressing the problems.