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Yoshizawa Shuji, Satoko Tanaka
Dept. of Interdisciplinary Sci. and Eng., Meisei Univ.
Hodokubo,Hino, Tokyo 191-8506, JapanI
yoshizaw@es.meisei-u.ac.jp

ABSTRACT

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.

Keywords: Biochar, compostization, soils, carbon sequestration, GHG emission

INTRODUCTION

Preparation of biochar from biomass wastes

Carbonization with outside-heating typed furnace

Biochar was prepared from bamboo wastes, wood wastes and corn-cob as a raw material which were carbonized at 600oC to 700oC in outside-heating typed furnace as shown in Fig. 1.

Relative pore volume distribution of the bamboo biochar, wood biochar and corn-cob biochar is shown in Fig. 2 (a), (b) and (c), respectively. In the distribution of the charcoal from bamboo and concrete frame waste, the peak is centered in 0.1 - 1 µm. It is indicated that the pore diameter from 10 - 1,000 µm is major in the corn-cob charcoal. Fig. 3 (a) and (b) show the typical SEM photograph of cross section of bamboo biochar and wood biochar, respectively.

Low cost carbonization

It is important to carbonize the biomass material in the low cost for the usage of biochar for the farmland. Material is selected wooden pallet waste for transportation with a forklift was selected as charcoal material. The wood peaces place in a cage is covered with an iron box furnace and is kindled with fire, as shown in Fig. 4, which is called as a self-burning system. The carbonization temperature is 500 - 600oC.

Microorganisms proliferation by addition of biochar in food waste composting

Charcoal prepared from biomass (biochar), ashes and compost from biomass waste as a soil improver and fertilizer in a farm have been used for a long time in Japan. Y.

Miyazaki and R.Kaibara described their effect on farming in Encyclopedia of Agriculture published in 1697. G. Sugiura and M. Ogawa reported that charcoal has proliferation effect of symbiosis microorganisms such as root nodule bacteria and mycorrhiza in farm soil. It is well known that symbiosis microorganisms play an important role in growing plants. Recently, both carbonizing biomass waste such as wasted construction biomass materials, wasted paper and thinned wood and bamboo in forest and composting of garbage generated by homes, restaurants and food industries and livestock wastes and their utilization are receiving attention from the viewpoint of recycled biomass wastes and food safety by organic cultivation.

As wood and bamboo have pores of several to several ten micron meters originated from tracheae, charcoal prepared from carbonized wood and bamboo has also almost the same size of the pores. And size of the pores is almost the same size of the microorganisms. By adding charcoal from the beginning of composting, the proliferation of microorganisms was enhanced. It is expected, therefore, that the time required for making compost is shortened and compost contains a lot of microorganisms.

In this Section, the charcoal 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 microorganisms7)8), and morphology of the microorganisms in the mixture was observed by a scanning electron micrograph (SEM) technique.

Experimental

Rice bran composting

Flow chart of samples preparation is shown in Fig. 5. The charcoals pulverized and sifted into the size of 1 to 3 mm were used as a medium. Rice bran (17.8 g) as a nutrient was added into 15.5 g of bamboo charcoal powder in 300 ml flask. Weight ratio of the charcoal to the rice bran was 1: 1.15. Moisture content of the mixture was adjusted to 65% by adding distilled water. The mixture was treated at 120oC for 60 minutes with a high pressure sterilizer. Ten g of aerobic complex microorganisms (ACM) were added as a seed to the mixture. The samples were maintained in an incubated chamber with 53% of relative humidity (RH) at 23oC and stirred vigorously with spatula once a day for aeration.

Measurement

Microorganisms that proliferated on the surface of the charcoal were observed by SEM. After freeze-drying of the sample in liquid nitrogen in a vacuum, the sample was fixed by osmic acid evaporation. The surface was then coated with a thin film of sputtered Pt_Pd alloy.

The concentration of microorganisms was estimated by measuring the ATP concentration in the sample (Meidensha Corp., Luminometer UPD-4000). As ATP exists in mitochondria in the cytoplasm, the concentration of ATP can be used as an indication of microorganism activity. When ATP, to which d-luciferin has been added, changes to adenosine monophosphate in the presence of luciferase and Mg2+, light at a wavelength of 560 nm is emitted. Distilled water (20 ml) was added to 2 g of the sample and stirred with a tube mixer at 2500 rpm for 1 min. Then 250 ?l of this suspension was withdrawn with a micropipette and an ATP measuring kit (Meidensha Corp., Lucifer AS) added.

RESULTS AND DISCUSSION

Proliferation of microorganisms

The incubation time dependence of ATP concentration of the samples was measured. In Fig. 6, in the system mixed with charcoal, rice bran and ACM, the ATP concentration increases accompanied with three concentration peaks with increase of incubation time. In the systems, the mixture of charcoal and rice bran without ACM and the single component, ACM alone, charcoal alone, and rice bran alone, no increase of the ATP concentration is observed.

For studying influence of the charcoal amount on the microorganisms proliferation in the mixture of charcoal, rice bran and ACM, the logarithmical incubation time dependence of the ATP concentration in the mixture with different amount of charcoal, 1.0 g, 5.9 g and 15.5 g, is shown in Fig. 7. Increase rate and extent of the ATP concentration are dependent on the charcoal amount in the system. The result that ATP concentration increases in the mixture system with charcoal, rice bran and ACM, means that the charcoal could proliferate microorganisms in the system. Several peaks of the ATP concentration were found; two peaks at about 100 hr and 1,000 hr in the system with 1.0 g of charcoal, three peaks at 100 hr, 500 hr and 1,000 hr with 5.9 g of the charcoal, and three peaks at 70 hr, 200 hr and 400 hr with 15.5 g of the charcoal. The shifts from each peak in the incubation time depended on the amount of the charcoal. It was found that as the amount of the charcoal increased, the microorganisms proliferation was accelerated remarkably. From those results, there should be at least three kinds of microbial communities in the system whose proliferation rate is different. It is suggested that this comes from difference of the proliferation rate of adaptive microorganisms as a specific response to the presence of nutrient such as glucide, protein and lipid contained in rice bran as a main component. The proliferation rate may reflect the biodegradation property of the nutrients.

The cultivation time-dependence of ATP concentration of the samples is shown in Fig. 8. In the systems that used charcoal as a medium, the ATP concentration increases showing three peaks around 70 h, 190 h and from 300 to 350 h, respectively. This suggests that there are some kinds of microbial community whose proliferation rate is different.

SEM observation of microorganisms

SEM photographs of microorganisms found on the surface of mixture of the bamboo charcoal and the rice bran after 696 hours of the incubation were shown in Fig. 9. Granules like spores of Actinomadura, that have many bumps, were detected as shown in Fig. 9 (a). Microorganisms also shown in Figure 9 (b) are similar to Actinomycetes which have ramified structure observed in Cellulomonas and Agromyces. Fig. 10 (a), (b) and (c) show SEM photographs of microorganisms on and in the surface of the charcoal made from bamboo, concrete frame waste and corn-cob, respectively, after 336 hours of the incubation. Morphologically rod and short rod microorganisms can be observed on the surface and in the pores of charcoals. It was confirmed that charcoal functions as the matrix for these microorganisms and the composting microorganisms on and in the charcoal were morphologically diversified.

CONCLUSION

The appearances of microorganisms during the composting of rice bran by aerobic complex microorganisms in the existence of bamboo charcoal were investigated. The ATP concentration of the mixture was increased in stages, namely three peaks occurred, during the composting. Bamboo charcoal was considered to be available as a supporting matrix for microorganisms. In conclusion, the addition of charcoal into rice bran was considered to be effective for its composting by ACM.

Production of biochar mixed food garbage compost in the composting factory

In this Section, a composting factory dealing with 100 tons of food waste per day added with biochar in Japan is introduced.

Food waste composting factory

The composting factory in a suburban area of Tokyo deals 100 tons of food industry wastes a day added with charcoal. Undesired materials such as plastic, steel and aluminum materials are separated from food garbage with a separator as shown in Fig. 11. Then, charcoal of several % and returned compost are mixed to the garbage, and the mixture is thrown into the top of a fermentation tank in Fig. 12. The temperature of the mixture increases to 60-70oC, because aerobic microorganisms proliferate on the surface of the charcoal. After one week, the first fermented compost is pulled out of the tank. Then, the compost is piled for two months with aeration, and finally the matured compost is obtained.

Effect of biochar and compost usage in farmland on carbon sequestration, plant growth and soil aggregation

For global warming prevention, it is important to study the sequestration mechanism of carbon in soil of farmland where biochar and compost are used. By using biochar carbonized with biomass materials such as waste wood, bamboo and agricultural materials in farmland, carbon storage in the soil for long period is expected. In order to establish the sequestration mechanism of carbon in the soil used with charcoal and compost, analysis method of the undegradable carbon (UDC) amount in the soil was developed for quantitative estimation of the carbon sequestration.

As the soil properties are improved and soil microorganisms concentration increase with the addition of charcoal to the soil, the plant growth promotion in the farmland is also expected. By using biochar carbonized from biomass materials in the farmland, carbon sequestration for a long period and plant growth promotion due to soil property improvement are expected. The soil property improvement, such as water-holding ability and water- and air-permeability, partly comes from aggregation of the soil, because where there are a lot of micro voids and pores among the soil aggregates, which brings the soil softness and well-aerated environment. It is well known that the aggregates can be developed with microorganisms in the soil.

In this Section, in order to establish the sequestration mechanism of carbon in the soil used with charcoal, analysis method of the UDC amount in the soil is developed for quantitative estimation of the carbon sequestration. Secondly, the effect of charcoal using in the farmland on the spinach growth is studied. Finally, the aggregation of the soil in the farm land where biochar and/or compost were used is also studied.

Experimental

Material

Biochar was prepared from waste of wood pallet for transportation with folk lift as a raw material which was carbonized at 500oC-600oC in process of self-burning in the iron box furnace. Some characteristics of charcoal as follows; specific surface area of 205 m2/g, bulk density of 0.2 g/ml, pH of 8.1 and grain size of under 3 mm in diameter.

The biochar powder and compost made from food garbage (Tanaka et al, 2005 and 2011; Yoshizawa et al., 2006) were used at the rate of 2 t/10 a and 1 t/10 a, respectively, to the red-clayey soil farmland located in the suburbs of Tokyo. For evaluation of spinach (Spinacia oleracea) growth in the farmland, the weight distribution of the spinach leaves and roots was measured, respectively.

Analysis of carbon amount

Fig. 13 shows the analytical method of estimation of UDC amount. The total carbon amount (T-C) and the inorganic carbon amount (TIC) derived from carbonate in the soil of the farmland were measured with the solid sample combustion method. The organic carbon amount (TOC) was measured with the Tyulin method (the titration method). The UDC amount was estimated by deducting the TIC amount and the TOC amount from the T-C amount.

Soil aggregation

The structure of the aggregate was estimated with the wet screen method. Several grams of the soil sample was put through the set of sieves 2 mm, 1 mm, 500 ?m, 250 ?m and 100 ?m placed in a vessel filled with water, and then the vessel was slowly shaken up and down for 5 mins. After sample over the each sieve was dried for 24 hrs at 105oC, it was weighed. The mean weight diameter (MWD) of the soil was calculated with particle diameter (mm) and the integration number of the aggregate (%).

The surface of the aggregates was observed by scanning electron micrography. After the sample was freeze-dried in liquid nitrogen in a vacuum, it was fixed by osmic acid evaporation. The surface was then coated with a thin film of sputtered Pt_Pd alloy.

RESULTS AND DISCUSSION

Carbon Sequestration

Time dependence of various carbon amounts in the soil of the farmland was shown in Fig. 14. The T-C, TOC and UDC amounts in the soil used with the charcoal and the compost remain larger than those in the soil with the compost.

Plant growth

Fig. 14 shows photographs of the appearance of spinach grown in the farmland. It was observed that the plants grew largely in the soil with the charcoal and the compost rather than that in the soil with the compost. Small plants were cropped in the soil without the charcoal and the compost. The results of the plant growth corresponded largely with the UDC amount in the soil.

Quantitative comparisons of the leaf and root fractions of spinach growth are shown in Fig. 15 and Fig. 16, respectively. In the weight distribution of the leaf part, the spinach leaf grown in the soil with the charcoal and the compost yielded 10% in weight ratio on 30 - 40 g and 40 - 50 g fractions, respectively, where is no existence of the spinach leaf grown in the soil with the compost and without additives. In the weight distribution of the root part, 2% and 13% of the spinach root were in 1.5 - 2 g and 1 - 1.5 g fractions, respectively. With the compost, 22% of the root was in 0.5 - 1 g fraction. There only exists the root without additives in the 0 - 0.5 g fraction (Fig. 17).

It was suggested that the stimulation of the spinach growth in the soil used with the charcoal and the compost came from the improvement of the physical and biological property of the soil.

Soil aggregation

Fig. 18 shows the accumulation curve of the particle size of the soils sampled after 10 days from using biochar and compost in the farmland. In the soils with non-additives and with the biochar, fractions under 250 ?m are 65%, which decrease 44 - 51% in the soils used with the compost and biochar mixture and with the compost, accompanied with the increase of aggregates from 1 to 5 mm.

Fig. 19 shows time dependence of the MWD value of the soil. The MWD value of the original soil in the farmland was about 30 at the beginning of the test. In the soil without additives, the aggregate was scarcely developed. In the initial period after using the biochar and the compost mixture and compost, the MWD value increased to 50 - 60, and then gradually decreased.

Fig. 20 (a) shows the SEM photograph of the typical aggregate of the soil with the biochar and the compost. The diameter of the aggregate, was almost 2 mm with smooth surface. Magnified photographs on the surface of the aggregate are shown in Fig. 20 (b), (c) and (d). Many kinds of microorganisms that proliferated on the surface were observed. It was suggested that the soil was aggregated with microorganisms proliferated on the surface of the aggregate in the soil.

Fig. 21 shows time dependence of ATP concentration of the soil. The ATP concentration increased drastically after using the biochar and the compost, and about the half value of which was observed in the soil with compost and without charcoal, and then the ATP concentration of both of the soils gradually decreased. There no change of the ATP concentration was observed in both of the soils with biochar and without additives.

It was suggested that this increase of the ATP concentration in the soil with the biochar and the compost came from the accelerated proliferation of the microorganisms on the surface of the biochar. Wood has pores that range from several to several tens of microns in diameter and originate from tracheae and charcoal prepared from carbonized wood has pores of almost the same size.

CONCLUSION

Estimation method of UDC content based on the biochar used in the farmland soil was established.

Growth stimulation of the spinach in the farmland used with the charcoal and the compost was observed.

The aggregation of the soil in farmland was developed by using the biochar and the compost. It was suggested that the soil was aggregated with microorganisms proliferated on the surface of the aggregate in the soil.

Effect of charcoal and compost in farmland on GHGs emission

INTRODUCTION

For global warming prevention, it is important to study the mitigating mechanism of green house gases (GHGs) emission in farmland where biochar and compost are used. During biodegradation of the compost containing organic carbon and nitrogen in the farmland soil, many kinds of GHGs emit in farmland; carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). As the global warming potential (GWP) of CH4 and N2O is 25 and 250, respectively, the global warming can be mitigated by suppression of the emission of these high GWP gases.

In this Section, the effect of charcoal using in the farmland on the emission of CO2, CH4 and N2O is studied.

Experimental

Sampling of GHGs

The GHGs were sampled with the closed chamber method. The chamber size is 40 cm in diameter and 15 cm depth. 50 mL. The GHGs were sampled at 0 min., 20 min. and 40 min. with a glass syringe and injected into a vacuumed Vial bottle and stored in the positive pressure state.

GHGs flux measurement from the soil

Table 1 shows gas chromatography (GC) measurement methods of GHGs.

RESULTS AND DISCUSSIONS

CO2 Flux

Fig. 22 shows CO2 flux from both the farmland soils with cropping and without cropping. In the early stage of 14 days, CO2 evolved largely from the soil used with compost rather than the soil without compost. It was also found that more CO2 evolved in the soil with biochar and compost than in the soil with compost. As microorganisms density increases in the soil with biochar and compost, as shown in Fig. 22, the organic compounds in the compost change to CO2 in the short time.

N2O Flux

Fig. 23 shows N2O flux from the farmland soil with cropping and without cropping. As shown in Figures 23 (a) and (b), in one day after the compost applicationin, a spike of N2O flux is observed in both the soils without cropping and with cropping, and less N2O evolved in the soil with biochar and compost than in the soil with compost. After the second day, Figures 23 (b) and (c) show N2O flux less than 2 mg-m2h-1 in all experimental wards. It was also found that regardless of with or without cropping less N2O evolved in the soil with biochar and compost than in the soil with compost.

CH4 Flux

Fig. 24 shows CH4 flux from the farmland soil with cropping. In the third day after the compost applicationin, peaks of CH4 flux were observed in all experimental wards. Irrespective of no addition of organic matter, CH4 flux was observed. This may be because CH4 existing among the soil grains and absorbing into the soil evolved in the air by cultivation of the soil with a tractor. In the range of 3 _ 9 days, CH4 flux decreases in the soil with biochar and compost and with biochar. With applying biochar in the soil, changing the anaerobic to aerobic state or absorption of CH4 with the biochar brought possibly in this decrease.

CONCLUSION

By applying biochar in the farmland soil, increase of CO2 flux and decrease of N2O and CH4 flux was recognized due to increase of the soil aerobic microorganisms density.

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.

REFERENCES

  • Imanishi T, Yasue H, Sakawa M. 2001. TANSO 200:249-254. (in Japanese).
  • Imanishi T. Sakawa M. 2003. J. Jpn. Soc. Mushroom Sci. and Technol. 11:165-171. (in Japanese).
  • Miyazaki Y, Kaibara R. 1697. Nogyo Zensho (Encyclopedia of Agriculture). (in Japanese)
  • Ogawa M. 1984. Res. J. Food and Agri. 7:41-46, (in Japanese) and 1987. Symbiosis Microorganisms Connecting between Plants and Soil, Nobunkyo Pub. Tokyo. (in Japanese).
  • Sugiura G.1984. Jozo Kyokaishi (J. Brewing Soc. Jpn.) 7:479-484. (in Japanese).
  • Tanaka S, Mineki S, Goto S, Yoshizawa S. 2011. Proc. 2nd Asia Pacific Biochar Conf., Kyoto, Sept. 15-17.
  • Tanaka S, Mineki S, Goto S, Yoshizawa S. 2011. Proc. 2nd Asia Pacific Biochar Conf., Kyoto, Sept. 15-17.
  • Tanaka S, Ohata M, Yoshizawa S, Mineki S, Fujioka K, Kokubun T. 2005, Proc. Inter. Conf. on Carbon (Carbon 2005), Gyeongju, Korea, July 3-7 S04-06.
  • Tanaka S, Onozawa O, Yoshizawa S. 2011. Extended Abstracts of Asia Pacific Biochar Conference (APBC 2011), Kyoto, Sept. 15-17.
  • Tanaka S, Yoshizawa S, Ohata M, Mineki S, Goto S, Fujioka K, Kokubun T. 2006. Trans. Mater. Res. Soc. Jpn. 31:981.
  • Yoshizawa S, Tanaka S, Ohata M, Mineki S, Goto S, Fujioka K, Kokubun T. 2006. TANSO 224 : 261.
  • Yoshizawa S, Tanaka S, Ohata M, Mineki S, Goto S, Fujioka K, Kokubun T.2006. TANSO 224:261-265.
  • Yoshizawa S. 2005. Proc. Inter. Sympo. on Utilization of Charcoal, Expo. Aichi, Japan. July 24, pp. 63-70.


Index of Images

  • Fig. 1 Bach-typed carbonizaer.

    Fig. 1 Bach-typed carbonizaer.

  • Fig. 2 Pore distribution of each radius in various charcoals; (a) bamboo charcoal, (b) wood charcoal and (c) corn-cob charcoal.

    Fig. 2 Pore distribution of each radius in various charcoals; (a) bamboo charcoal, (b) wood charcoal and (c) corn-cob charcoal.

  • Fig. 3 SEM photograph of cross section of (a) bamboo biochar and (b) wood biochar.

    Fig. 3 SEM photograph of cross section of (a) bamboo biochar and (b) wood biochar.

  • Fig. 4 Iran cover-typed carbonizer.

    Fig. 4 Iran cover-typed carbonizer.

  • Fig. 5 Flow chart of composting rice bran.

    Fig. 5 Flow chart of composting rice bran.

  • Fig. 6 Incubation time dependence of ATP concentration of the systems.

    Fig. 6 Incubation time dependence of ATP concentration of the systems.

  • Fig. 7 Incubation time dependence of ATPconcentration of the systems.

    Fig. 7 Incubation time dependence of ATPconcentration of the systems.

  • Fig. 8 Incubation time dependent of ATP concentration of the systems with different ACM from 0.01 g to 5.0 g.

    Fig. 8 Incubation time dependent of ATP concentration of the systems with different ACM from 0.01 g to 5.0 g.

  • Fig. 9 SEM photographs of the different type of microorganisms on the mixture surface of bamboo charcoal and rice bran.

    Fig. 9 SEM photographs of the different type of microorganisms on the mixture surface of bamboo charcoal and rice bran.

  • Fig. 10 SEM photographs of microorganisms in the surface of various charcoals; (a) bamboo, (b)concrete frame waste and (c) corn-cob.

    Fig. 10 SEM photographs of microorganisms in the surface of various charcoals; (a) bamboo, (b)concrete frame waste and (c) corn-cob.

  • Fig. 11 Separator of garbage from plastic bag.

    Fig. 11 Separator of garbage from plastic bag.

  • Fig. 12 Twelve fermentation tanks of 65 m3.

    Fig. 12 Twelve fermentation tanks of 65 m3.

  • Fig. 13 Estimation of undegradable carbon (UDC) amount in the soil.

    Fig. 13 Estimation of undegradable carbon (UDC) amount in the soil.

  • Fig. 14 Time dependence of (a) T-C amount, (b) TOC amount and (c) UDC amount in the soil.

    Fig. 14 Time dependence of (a) T-C amount, (b) TOC amount and (c) UDC amount in the soil.

  • Fig. 15 Effect of charcoal and compost on spinach growth.

    Fig. 15 Effect of charcoal and compost on spinach growth.

  • Fig. 16 Weight distribution of the leaf part per plant.

    Fig. 16 Weight distribution of the leaf part per plant.

  • Fig. 17 Weight distribution of the root part per plant.

    Fig. 17 Weight distribution of the root part per plant.

  • Fig. 18 Particle diameter distribution of the soil.

    Fig. 18 Particle diameter distribution of the soil.

  • Fig. 19 Time dependence of the MWD value of the soil.

    Fig. 19 Time dependence of the MWD value of the soil.

  • Fig. 20 SEM photographs of the aggregate of the soil with charcoal and compost mixture.

    Fig. 20 SEM photographs of the aggregate of the soil with charcoal and compost mixture.

  • Fig. 21 Time dependence of ATP concentration of the soil.

    Fig. 21 Time dependence of ATP concentration of the soil.

  • Fig. 22 Time dependence of CO2 flux from the soil.

    Fig. 22 Time dependence of CO2 flux from the soil.

  • Fig. 23 Time dependence of N2O flux from the soil.

    Fig. 23 Time dependence of N2O flux from the soil.

  • Fig. 24 Time dependence of CH4 flux from the soil with cropping.<BR>

    Fig. 24 Time dependence of CH4 flux from the soil with cropping.

  • Table 1 Method for measurement of GHG

    Table 1 Method for measurement of GHG

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