Published November 12, 2015
The Effects of Biochar Amendment on Soil Fertility Avanthi Deshani Igalavithana, Yong Sik Ok, Adel R.A. Usman, Mohammad I. Al-Wabel, Patryk Oleszczuk, and Sang Soo Lee* Abstract
Biochar is a black, C-rich, stable, solid product from pyrolysis of biomass materials. Although it was known as a soil C sequester for a considerable length of time, biochar is also recently advocated in agricultural applications for improving soil quality; therefore, its agronomic value is evaluated. This paper summarizes and discusses the potential of biochar amendment for soil fertility improvement and the effects on crop productivity by reviewing scientific studies performed around the globe. Researches have shown that biochar amendment significantly enhances the nutrient availability and nutrient retention of a wide range of soils. The soil fertility amelioration is achieved through improving soil physical, chemical, and biological properties. The capacity of a biochar to provide or enhance soil available nutrients, however, is determined by the feedstock and production conditions of the biochar. Biochars produced from nutrientrich feedstocks contain comparatively high readily available nutrients. In general, biochar amendment improves soil fertility, yet the effect is more apparent for poor (e.g., acidic, highly leached) soils than for originally fertile soils. The impacts of biochar amendment on crop growth are largely positive, with mixed results dependent on the biochar quality, application rate, soil type, and crop species. Further research is needed to fully uncover the role of biochar in enhancing soil fertility and crop growth.
Abbreviations: CEC, cation exchangeable capacity. Avanthi Deshani Igalavithana (
[email protected]), Yong Sik Ok (
[email protected]), and Sang Soo Lee, Korea Biochar Research Center and Dep. of Biological Environment and, Kangwon National University, Chuncheon 24341, South Korea; A.R.A. Usman, Dep. of Soils and Water, Faculty of Agriculture, Assiut University, Assiut 71526, Egypt (
[email protected]); Mohammad I. Al-Wabel, Soil Sciences Dep., College of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia (
[email protected]); Patryk Oleszczuk, Dep. of Environmental Chemistry, Faculty of Chemistry, 3 Maria Curie-Skłodowska Square, 20-031 Lublin, Poland (
[email protected]). *Corresponding author (sslee97@kangwon. ac.kr). A.D. Igalavithana and Y.S. Ok share first authorship.). doi:10.2136/sssaspecpub63.2014.0040 Agricultural and Environmental Applications of Biochar: Advances and Barriers. SSSA Special Publication 63. M. Guo, Z. He, and M. Uchimiya, editors. © 2015. SSSA, 5585 Guilford Rd., Madison, WI 53711, USA.
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Soil fertility is the ability of a soil to supply plant nutrients to maintain sustain-
able crop productivity. Soil fertility degradation and available nutrient depletion is common in agroecosystems with environmentally detrimental amounts of modern agricultural practices, which have imbalanced the responsible abiotic and biotic soil fertility factors (Suzuki et al., 2014). Soil fertility enhancement and maintenance are challenges nowadays, as soil nutrient availability and retention have generally been declining. It is clearly urgent to reverse the trend to sustain the soil fertility of agroecosystems. Application of organic amendments such as compost and animal manure is a traditional practice to rehabilitate soil nutrient retention. The traditional organic amendments, however, are of short life span in soil; continuous application in bulk quantities diverts its attention of this practice. Moreover, the increasing population pressure does not allow fallowing cropland to gain the diminished soil fertility through natural rehabilitation (Achard and Banoin, 2003). Terra preta or Amazonian dark earths are fertile anthrosols generated by ancient Amazonian inhabitants. The high fertility of terra preta has been investigated in details by many scientists; a large amount of stored C with a high degree of stability, as in a form of charcoal, has been identified for the attractive fertility (Petersen et al., 2001; Schmidt et al., 2014). From the archeological perspective, terra preta attained its fertility as a result of the addition of charcoal and animal bones (Petersen et al., 2001; Schmidt, 2010, 2013; Schmidt et al., 2014). In general, the content and stability of soil organic C are known as very important factors for maintaining soil fertility (Lal, 2004; Liu et al., 2013; Pan et al., 2009). Hence, applying biochar to soils might have fertility enhancement effects as implicated by charcoal abundance in terra preta soils (Akhtar et al., 2014). Biochar is a C-rich, stable, anthropogenic product obtained by thermal decomposition of biomass with little or no available oxygen at relatively low temperatures (
