Biochar characteristics and application in the agriculture

Biochar characteristics and application in the agriculture [

Martyna Glodowska, Malgorzata Lyszcz
Institute of Soil Science and Plant Cultivation – State Research Institute, Pulawy, Poland

Abstract 

Recently biochar gained importance as a way to deal with global climate change, by sequestering C into soils, but also as a soil amendment and bioremediation tool. Many studies have demonstrated the positive influence of biochar on soil quality and subsequently, plant growth, although the results are not consistent and climate seems to be the main reason for this inconsistency. Number of studies has been conducted to find out how biochar affect soil characteristic, fertilizers efficiency as well as soil microbiota. The main focus of this review is to discuss biochar features and it application in agricultural practices that could improve soil productivity and in consequence plant growth and development.

1. Introduction 

Biochar, although not in the form we know today, has been used since centuries. The incorporation of charcoal into the soil to enhance soil quality has been an agricultural practice for thousands of years (Xu et al. 2012). Pre-Columbian people were combining charred residues of organic and inorganic wastes with the soils that are known today as Terra Preta - rich in organic matter and nutrients Amazonian soil. The oldest description of charcoal use in agriculture may be from the 17th century Encyclopedia of Agriculture by Yasusada Miyazaki, where he cited an even older textbook from China. We know from there that rice husk charcoal has been used as a soil amendment probably since the beginning of rice cultivation in Asia (Ogava and Okimori, 2010). Nowadays, the term “biochar” refers to a product of biomass pyrolysis, wherein plant-based materials are heated under anaerobic conditions to capture combustible gases. Originally, biochar production was associated with slow pyrolysis, characterized by a long time (more than 10 h) under relatively low temperature, typically around 400°C. More recently, there has been growing interest in biochar production through fast pyrolysis, where the organic materials are rapidly heated to 450-600°C (Xu et al. 2012). The reason why biochar gained public interest is mainly associated with its carbon sequestration ability. Biochar is a promising tool to reduce the atmospheric CO2 concentration because it slows the return of photosynthetically fixed carbon to the atmosphere (Xu et al., 2012). The half-life of biochar in the soil is estimated to range from hundreds to thousands of years (Zimmerman 2010). Therefore, supplying the soil with biochar is a strategy for long-term carbon sequestration. Moreover, there is increasing interest in biochar as a soil amendment. Number of studies has demonstrated that biochar application can significantly improve crop productivity (Chan et al. 2007), improve soil conditions (Xu et al., 2012), and increase the efficiency of fertilizers (Asai et al., 2009), it can also be used in remediation processes (Chan et al., 2012). The main goal of this paper is to review the effect of biochar on soil properties and discuss it use in the agricultural practices.

6. Conclusion 

Biochar became [could become?] an important tool to mitigate the climate changes caused by anthropogenic activities. But as it is presented above biochar can also be successfully used in agricultural sector. The literature review presented above suggests that biochar is a material that significantly affects soil quality by changing its structure as well as chemical composition. It can be used in the water stress management and in the bioremediation processes, particularly in recovery of the soils contaminated with PAHs and heave metals. There are a growing number of evidences showing positive effect of biochar on plant growth and development; however this effect is strongly related to the climate and soil type. Also, biochar when applied together with mineral or organic fertilizers seems to significantly improve fertilizer efficiency and use by the plant. Finally, biochar was found to cause important changes in soil microbiota structure and function and it is believe to create favorable conditions for microorganisms.