Biochar and Compostization: Maximization of Carbon Sequestration with Mitigating GHG Emission in Farmlands

ABSTRACT, FFTC

In Japan charcoal has been used for a long time as environmental improver, soil improver in a firm, water purification material and odor adsorbent. It was reported that biochar has proliferation effect of symbiosis microorganisms such as root nodule bacteria and mycorrhiza in farm soil2)3). It is well known that symbiosis of microorganisms play an important role in growing plants. As wood and bamboo have pores of to ten micron meters originated from tracheae, charcoal prepared from carbonized wood and bamboo has almost the same size of the pores. And size of the pores is as almost same as the size of microorganisms.

In Section 2, low cost carbonization process is introduced, because biochar applied for agriculture should be low cost.

In Section 3, on charcoals made from various kinds of biomass, bamboo, wood and corn-cob, added with complex microorganisms used for composting. The proliferation of microorganisms was studied by measuring incubation time dependence of adenosine triphosphate (ATP) concentration from the microorganisms, and morphology of the microorganisms in the mixture was observed by a scanning electron micrograph (SEM) technique.

In Section 4, an example of composting of food wastes and biochar mixture in Japan is introduced. The composting factory in a suburban area of Tokyo deals with 100 tons of food industry wastes a day added with several % of biochar.

In Section 5, wood charcoal powder and compost made from food garbage were used at the amount rate of 2 t/10 an and 1 t/10 a, respectively, to the red-clayey soil farmland located in the suburbs of Tokyo.

In Section 6, Green house gases (GHGs) from the soil in the farmland were collected with a closed chamber method and analyzed with gas chromatography. Just after usig compost in the farmland, CO2 and N2O emission were observed in a short time. CH4 emission amount from the soil with biochar-compost was smaller than that from the soil with compost. It was concluded that the addition of the biochar is effective in making the soil aerobic state.