1a. Objectives (from AD-416):
1. To evaluate the production and optimize the pyrolytic process of crop and tree feedstocks to create designer biochars with tailored chemical and physical characteristics. 2. To examine the impact of these designer biochars on soil fertility, carbon sequestration, microbial communities, volatile matter, and greenhouse production through both short- and long-term laboratory incubations.
1b. Approach (from AD-416):
Scientists from the Environmenta Protection Agency (EPA) and USDA-ARS will coordinate a 5-year collaboration that will produce designer biochars by pyrolysis of traditional (i.e., switchgrass, pecan shells, peanut hulls, livestock manure, begasse, cotton gin trash, etc.) and emerging biofuel feedstocks (sorghum, miscanthus, poplar, etc.). The designer biochars will be produced in-house by altering feedstock selection, pyrolysis temperature and residence time. ARS scientists in Florence have produced between 1 to 2 kg of biochar per day, which was sufficient to conduct several bench-scale soil incubation laboratory studies. The designer biochars are characterized for chemical, physical, and structural properties using a battery of assays including pH, total elemental analyses, volatile matter, and 13C nuclear magnetic resonance spectroscopy. This information provides characteristics to determine which designer biochar could be selected to remediate specific soil quality issues. Only a limited number of traditional ligno-cellulose feedstocks have been processed. This study intends to use the next generation biofuel feedstocks to create more designer biochars. Past evaluations using designer biochars made from traditional feedstocks have shown that some designer biochars have minimal impact on soil fertility, and manure-based biochars are nutrient-enriched. We intend to conduct additional experiments by blending biochars to reduce undesirable soil fertility properties of manure-based biochars with the emerging biofuel ligno-cellulose-based biochars. Blended designer biochars will be characterized by ARS scientists in Florence and St. Paul and EPA. The blended and unblended designer biochars' impact on soil fertility, carbon sequestration, microbial processes, volatile matter and greenhouse gas production will be evaluated through both short- (h to d) and long-term (30 to 120 d) laboratory incubation studies.
3. Progress Report:
This project relates to inhouse project objective 1: to determine if biochars can be manufactured with tailored characteristics by changing the feedstock ratio, pyrolysis temperature, and the particle size of the resultant biochar. Biochars are being used globally as a soil amendment to improve soil quality and tilth, especially in marginal or degraded soil. Previous reports have shown that one biochar type cannot solve every soil quality issue in all soils. Biochars produced under these technical conditions did vary in their chemical and physical properties. Later, laboratory pot incubation experiments showed that these designer biochars successfully improved specific soil issues such as low carbon sequestration, and water and nutrient retention. Results show that biochars can be created by changing manufacture conditions in such a way that the designer biochars can be used to resolve specific soil quality and tilth deficiencies.