Biochar’s Recent Comments

• Click here to view comment in original post

  management options for biochar

  The study of Wardle et al provides valuable data. 10 year studies are a rare opportunity. We knew earlier that charcoal increases the decomposition of labile soil organic matter (SOM). This is a logical consequence of increased microbial biomass and activity but nobody measured this before in a 10 years study.
  This is the example of humus rich Swedish forest soils. The Terra Preta example is different (low respiration rates in absence of an easily degradable organic substance). Chernozems are another example. Charcoal can led to the formation of very persistent SOM and this in environments and soils with low carbon sequestration capacity. Nobody proposed to apply charcoal as a C sink in humus rich soils. It can be a mean of carbon sequestration in depleted soils (e.g. southeastern US). Due to agriculture most soils have lost 50% of their original carbon content. The recalcitrance of charcoal allows SOM build up beyond the carrying capacity of a soil.
  In some cases increased decomposition might be even desired. Composting of manures and other green biomass would be increased and emissions of CH4 and N2O reduced. Organically applied nutrients might be faster available for plants if applied with charcoal and leaching of nitrogen reduced.
  This study proves once again the recalcitrant nature of charcoal and shows that we have to do much more research in the field to determine appropriate applications for charcoal as a C sink. I am confident that there are many management options.
  On Monday bummer blogging posted 1 year, 6 months ago 17 Responses

• Click here to view comment in original post

  charcoal carbon

  You are right the C/N ratio is important for decomposing material. The tissue of microbes are contend C and N in a certain ratio. If a C rich biomass applied and decomposed by microbial activity the microbial biomass is growing as a consequence. If there is not enough N in the biomass this process is causing N immobilization. What if the biomass does not get decomposed? If the microbes are unable to utilize the C source (supplied as biochar)?
  The microbial biomass would not grow, it would be limited by C not by N. Each plastic pot has a wide C/N ratio but does not cause N immobilization because the pot is not consumed by the microbial population.
  On Monday bummer blogging posted 1 year, 6 months ago 17 Responses