Biochar as a global change adaptation: predicting biochar impacts on crop productivity and soil quality for a tropical soil with the Environmental Policy Integrated Climate (EPIC) model

Abstract

The Environmental Policy Integrated Climate (EPIC) model with newly-developed biochar algorithms was used to determine the impacts of biochar amendments on corn (Zea mays L.) yields, soil cation exchange capacity (CEC), pH, bulk density (Db) and soil organic carbon (SOC) dynamics. The objectives were (1) to determine biochar impacts on crop yields and soil properties of a tropical soil and (2) to evaluate biochar’s potential as a climate change adaptation tool. EPIC was validated using results of a 4−yr experiment performed on an Amazonian Oxisol amended with biochar at rates of 0, 8, and 20 Mg ha−1. Simulated yields of corn on biochar amended soil were significantly greater than control yields (p < 0.05). Simulated soil pH increased from original 3.9 to 4.19, CEC increased from 9.76 to 11.5 cmolc kg−1, and SOC also increased. After validation, EPIC was used to simulate the impacts of the same biochar rates applied at 4 year intervals on corn yields and soil properties over the next 20 years. Soil CEC increased from 11.1 cmolc kg−1 to 20.2 cmolc kg−1 for the highest biochar application rate. Soil pH increased from 3.9 to 5.64. SOC increased up to 2.59 % for the highest biochar application rate with decreased topsoil Db from 1.11 Mg m−3 to 0.97 Mg m−3. Long-term corn yields were slightly decreased. Although the results are biochar-, dose-, and soil-specific, biochar additions to tropical soils hold promise as a climate change adaptation tool resulting in increased soil carbon sequestration and improved soil properties.