(1) 中国科学院烟台海岸带研究所 海岸带环境过程与生态修复重点实验室

Biochars have a range of functions from improving soil properties and remediating contaminated soils to reducing greenhouse gas emission from soil and increasing carbon content in soil.Their large-scale application,however,has been constrained by high costs of production and transportation.To solve this problem,a novel method has been developed for biochar production in the field with a coupled oxygen-limiting and mist-spraying technique.Agricultural and forest residues are placed in a soil trough and compacted layer by layer,a steel square tube with multiple holes is imbedded in the biomass,and an iron mesh is put on the top of it.The tube has the function of adjusting ventilation and oxygen supply to maintain flame temperature during biomass burning;and the mesh allows for the formation of a water film to limit oxygen supply.In field operations,cotton stalk or Salicaceae in the trough is ignited at one direction,whereas reed straw is ignited at multiple positions,for biomass carbonization,followed by water mist spraying layer by layer for a quick stop of carbonization.The biochars thus obtained have a yield of about 30%and are relatively homogeneous.They have abundant carboxyl group (0.71-1.43 mol/kg)and phenolic hydroxyl group(0.43-1.09 mol/kg)and a specific surface area of 45.5-83.2 m~2/g.Being able to produce goodquality biochars directly in the field at a low cost,this method makes feasible agricultural and environmental application of biochars.