Water infiltration and gas diffusion and therefore CO2 production vary a lot with soil texture. CO2 production is 20 to 40% less in clayish soils than in silty ones, but around 50% greater than sandy soils. However, the proportion of total carbon respired is higher if the concentration in clay and silt increase. (Lou & Zhou 2006, 102).
2.4.7 Soil pH
Many chemical reactions are regulated by pH, and many enzymes in soil depend on it. Bacteria grow with pH interval between 4 and 9, and fungi from 4 to 6, so pH is im-portant for the growth and proliferation of soil microbes, and therefore soil respiration. Soils with pH 3 produce much less CO2 than soils with pH 4 due to the adverse effect of low pH on soil microbial activity. Production of …show more content…
Some of these compounds are used to grow leaves, stems and roots; and some are broken down to supply energy to the plant. (Lou & Zhou 2006, 17-18).
During this process, CO2 is released again to the atmosphere by plant respiration. Dead plant materials are decomposed by microorganisms to provide energy and, at the same time, CO2 is released back to the atmosphere by microbial respiration. This microbial respiration also takes place during the decomposition of soil organic matter (SOM), which is a mixture of live microbial biomass and organic residuals of dead plants and dead microbes. (Lou & Zhou 2006, 17-18).
Therefore, through the ecosystem cycle, CO2 is produced by plant respiration (Rp), also called autotrophic respiration and microbial respiration (Rm), also called heterotrophic respiration. Autotrophic respiration can be separated in aboveground plant respiration (Ra) and belowground (root) plant respiration (Rb).
Rp= Ra + Rb Equation 5
In the steady state, the CO2 flux in the soil surface (Rs) is the sum of root respiration and microbial …show more content…
(Lou & Zhou 2006, 18-19).
FIGURE 2.5.1. Diagram of ecosystem carbon processes. (Luo & Zhuo, 2006, p. 18).
Soil respiration is also related to ecosystem production, which is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. Gross primary production (GPP) is the annual carbon assimilation by photosynthesis ignoring photorespiration. Net ecosystem production (NEP) is GPP minus ecosystem respiration Re:
NEP = GPP – Re = GPP – Ra – Rs Equation 8
This relationship between production and respiration can be also done through net pri-mary production (NPP) as:
NEP = NPP – Rm = NPP + Rb -Rs Equation 9
Net primary production is the rate at which all the plants in an ecosystem produce net useful chemical energy; it is equal to the difference between the rate at which the plants in an ecosystem produce useful chemical energy (GPP) and the rate at which they use some of that energy during respiration. (Wikipedia
2.4.7 Soil pH
Many chemical reactions are regulated by pH, and many enzymes in soil depend on it. Bacteria grow with pH interval between 4 and 9, and fungi from 4 to 6, so pH is im-portant for the growth and proliferation of soil microbes, and therefore soil respiration. Soils with pH 3 produce much less CO2 than soils with pH 4 due to the adverse effect of low pH on soil microbial activity. Production of …show more content…
Some of these compounds are used to grow leaves, stems and roots; and some are broken down to supply energy to the plant. (Lou & Zhou 2006, 17-18).
During this process, CO2 is released again to the atmosphere by plant respiration. Dead plant materials are decomposed by microorganisms to provide energy and, at the same time, CO2 is released back to the atmosphere by microbial respiration. This microbial respiration also takes place during the decomposition of soil organic matter (SOM), which is a mixture of live microbial biomass and organic residuals of dead plants and dead microbes. (Lou & Zhou 2006, 17-18).
Therefore, through the ecosystem cycle, CO2 is produced by plant respiration (Rp), also called autotrophic respiration and microbial respiration (Rm), also called heterotrophic respiration. Autotrophic respiration can be separated in aboveground plant respiration (Ra) and belowground (root) plant respiration (Rb).
Rp= Ra + Rb Equation 5
In the steady state, the CO2 flux in the soil surface (Rs) is the sum of root respiration and microbial …show more content…
(Lou & Zhou 2006, 18-19).
FIGURE 2.5.1. Diagram of ecosystem carbon processes. (Luo & Zhuo, 2006, p. 18).
Soil respiration is also related to ecosystem production, which is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. Gross primary production (GPP) is the annual carbon assimilation by photosynthesis ignoring photorespiration. Net ecosystem production (NEP) is GPP minus ecosystem respiration Re:
NEP = GPP – Re = GPP – Ra – Rs Equation 8
This relationship between production and respiration can be also done through net pri-mary production (NPP) as:
NEP = NPP – Rm = NPP + Rb -Rs Equation 9
Net primary production is the rate at which all the plants in an ecosystem produce net useful chemical energy; it is equal to the difference between the rate at which the plants in an ecosystem produce useful chemical energy (GPP) and the rate at which they use some of that energy during respiration. (Wikipedia