Guidelines for Specifications of Biochars for Use in Soils FINAL ...

123456789101112131415161718194.3 Test Category D - Advanced Analysis and Soil EnhancementPropertiesTest Category D is optional for all biochar materials. Producers may report on none, one, some,or all of the properties contained in the Test Category D set of advanced analysis and soilenhancement properties, using the prescribed test methods. Biochar advanced analysischaracteristics are electrical conductivity, porosity, and surface area of biochars. Biochar soilenhancement properties identify plant nutrients contained in the biochar.Biochars tested under Test Category D may report on any or all of the properties presented inTable 4 below:Table 4: Test Category D Characteristics and CriteriaTest Category D: Biochar Advanced Analysis and Soil Enhancement Properties - Optionalfor All BiocharsRequirement Criteria Unit Test MethodMineral N(ammonium andnitrate)Total Phosphorus &Potassium (P&K)*DeclarationDeclarationmg/kg% contentAvailable P Declaration mg/kgElectricalConductivityDeclarationdS/m2M KCl extraction, followed by spectrophotometry(Rayment and Higginson 1992)Modified dry ashing followed by ICP (Enders andLehmann 2011)2% formic acid followed by spectrophotometry(modified from Rajan et al 1992, Nutrient Cycl inAgroecosystems 32:291-302 and AOAC 2005, asused by Wang et al. 2011 Submitted to Plant andSoil)EC analysis procedures as outlined in section04.10 of US Composting Council and USDepartment of Agriculture (2001), followingdilution and sample equilibration methods fromRajkovich et al. (2011) See Appendix 3.Porosity Declaration cm3/g ASTM D 6556-10 Standard Test Method forCarbon Black – Total and External Surface AreaSurface Area Declaration m2/g by Nitrogen Adsorption* Total K is sufficiently equivalent to available K for the purpose of this characterizationInternational Biochar Initiative – Guidelines for Specifications of Biochars for Use in Soils 16