ACE Soil Respiration土壤呼吸测量技术(英文) PPT课件.ppt

Soil Respiration
Stephen Bonnage
Director
Soil Respiration and the Carbon cycle

Soil: 4th largest pool
2nd largest source to atmosphere
Soil Respiration
Q. What is soil?
Soil is plex mixture of mineral matter, organic matter and anisms
Soil Respiration
What are anisms?
Roots
Algae
Bacteria
Fungi
Earth worms
Insects
Soil Respiration
Q. How many?
A. 1 gram of soil typically holds anisms than there are people on the Earth
109 microbes in 1 gram of soil
Soil Respiration
Q. What is soil respiration?
A. All anisms, whether animal or microbe, produce CO2 gas as a by-product of the process of respiration.
Soil Respiration
As Raich and Schlesinger (2002) point out,
"The rate at which CO2 moves from the soil to the atmosphere is controlled by the rate of CO2 production in the soil (the true soil respiration rate), the strength of the CO2 concentration gradient between the soil and the atmosphere, and properties such as soil pore size, air temperature and wind speed that influence the movement of CO2 through and out of the soil."
These factors will be important to consider when assessing various attempts to quantify measurement methodologies.
Soil Respiration
Raich and Schlesinger (1992) estimated that global soil respiration consists of 50 Pg C/year from detritus and 18 Pg C/year from live roots and mycorrhizae. Soil respiration rates have been reported to be higher in grasslands than in forests, and higher in deciduous forests than in coniferous forests
Soil Respiration
Raich and Tufekcioglu (2000) reported in a review paper that root contribution to total soil respiration is high in cold, northern climates such as arctic tundra (50-93%) and boreal forests (62-89%). Temperate forests are lower, with 33-50% in broad-leaved forests, 35-62% in pine forests, and 12-40% in grasslands and croplands. Due to the wide range of the reported values, they could not establish a correlation between vegetation type and root con