**2.3 Biological activity**

*Applications of Biochar for Environmental Safety*

**Properties Effect of biochar application on various factors**

> stimulating plant growth, which then consumes more CO2 in a positive feedback

Biochar can reduce the need for chemical fertilizers, resulting in reduced emissions of greenhouse gases from fertilizer

Biochar can reduce emissions of nitrous oxide (N2O) and methane (CH4), two potent greenhouse gases from agricultural soils.

Biochar can increase soil microbial life, resulting in more carbon storage in soil.

Converting agricultural and forestry waste into biochar can avoid CO2 and CH4 emissions otherwise generated by the natural decomposition or burning of the

synthesis gases generated during biochar production can be used to displace carbon positive energy from fossil fuels.

Soil fertility Biochar can improve soil fertility,

effect.

waste.

*Biochar and its beneficial component in the environment.*

Energy generation The heat energy and also the bio oils and

manufacture.

Reduced fertilizer

Reduced N2O and CH4 emissions

Enhanced soil microbial life

**Table 1.**

Reduced emissions from feed stocks

inputs

(BET) surface areas of olive kernel biochars increased with increasing mass loss (burn-off) regardless of the activation temperature [21]. Micropores (<2 nm in diameter) are responsible for adsorption and high surface area the total pore volume of the biochar will be divided as microspores (pores of internal diameter less than 2 nm), mesopores (pores of internal width between 2 and 50 nm) and macropores

Soil application of biochar resulted in a significant increase in soil pH. Van et al. suggested that biochar derived from poultry litter facilitates liming in soil resulting in the rise of pH of acidic or neutral soils. Hoshi et al. in his experiment suggested that the 20% increase in height and 40% increase in the volume of tea trees were partly due to the ability of the biochar to maintain the neutral pH of the soil. Such ability is related to the liming value of the biochar. Van et al. reported a nearly 30–40% increase in wheat height when biochar produced

not to neutral soil. The increase in soil organic carbon with the application of biochar might have resulted from the recalcitrant nature of carbon found in biochar which is largely resistant to decomposition [1, 23–25] also reported that soil carbon increased significantly over control. Available N, P and K applying biochar to forest soils along with natural or synthetic fertilizers have been found to increase the bioavailability and plant uptake of P, alkaline metals and some trace metals [2, 19, 25] but the mechanisms for these increases are still a matter of speculation. Lehmann et al. demonstrated the ability of biochar to

to an acidic soil but

**References**

[13]

[14]

[15]

[16]

[15]

[17]

(pores of internal width greater than 50 nm) [22].

from paper mill sludge was applied at a rate of 10 t ha<sup>−</sup><sup>1</sup>

**2.2 Chemical properties**

**112**

Ameloot et al. showed that the type of biochar alone has a significant effect on soil enzymatic activity. The quoted authors proved that poultry litter biochar produced at 400°C and amended to soil 20 t ha<sup>−</sup><sup>1</sup> caused a significant increase in the activity of dehydrogenases. Biochar has a positive effect on mycorrhizal


### **Table 2.**

*Various physico biochemical properties of biochar.*

association when applied to soil [37–39] evaluated the increase in microbial biomass when biochar is applied to the soil and its efficacy as a measure of CO2 released per.

Microbial biomass carbon in the soil increase in basal respiration due to addition of the carbon in soil. Biochar does not contribute directly to the microbial population in the soil. Hence higher porosity of biochar creates a favorable environment for microbes to make a habitat in soil [40] researchers have suggested that biochar benefits microbial communities by providing suitable habitats for microorganisms that protect them from predation [41–43]. Microbial cells typically range in size from 0.5 to 5 μm and consist predominantly of bacteria, fungi, actinomycetes, lichens, and algae species are from 2 to 20 μm [44]. The microscopic studies indicate that biochar in soil serve as habitat for microorganisms [3]. The loss of volatile and condensable compounds from biochars and the concomitant relative increase in the organized phase formed by graphite-like crystallites leads to the increase in solid density (or true density) of the round 1.5–1.7 g cm<sup>−</sup><sup>3</sup> . Increasing anthropogenic activities have mainly resulted into buildup of non-essential heavy metals in agricultural soils. Recently chromium (Cr) contamination in water and soil is a serious concern [44].
