Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 31, 2000
Publication Date: N/A
Technical Abstract: Carbon is the basic building block of plants, large amounts of carbon are captured into plants through the photosynthetic process. Capture of carbon is offset by respiration, releasing carbon dioxide back into the atmosphere. If we examine the carbon balance over a complete year, it is difficult to determine if there has been a change in the agricultural system. During the growing season, carbon dioxide from the atmosphere and soil is incorporated into plant material, leaves, grain, and roots. Once carbon is added to the soil, the agricultural land management practices begin the response. For example, there is a twofold response to no-till systems. The first effect is caused by the presence of the crop residue on the soil surface that reduces the diurnal range of temperature and decreases the soil evaporation rate. Both of these changes are beneficial to microbial activity because the soil microclimate doesn't undergo extremes in temperature and moisture conditions. The increased microbial activity breaks down the root material in the soil profile and increases the development of organic carbon pools within the soil. The longer the soil remains in an untilled condition, the larger the build up of organic matter in the upper soil profile. Tillage disturbs the soil profile and releases carbon dioxide to the atmosphere. However, soil respiration and release of carbon dioxide continue throughout the year and this release contributes to the carbon dioxide uptake by plants throughout the growing season. All of the carbon captured in plant material does not originate from the atmospheric pool and a portion comes from soil respiration. Managing this pool for the benefit of agriculture could prove to be challenging.