Project Number: 3640-12000-008-00
Project Type: Appropriated

Start Date: Mar 25, 2011
End Date: Mar 24, 2016

Objective:
1. Develop and test systems for sustainable co-production of food and fuel, as a contributor to the ARS Renewable Energy Assessment Project (REAP). 2. Develop guidelines for the optimization of soil fertility and C sequestration using organic and biochar amendments, for field and specialty crops. 3. Enable reduced N2O emissions from fertilized cropping systems through improved understanding of controlling mechanisms, as a contributor to the ARS Greenhouse Gas Reduction through Agricultural Carbon Enhancement network (GRACEnet).

Approach:
Field experiments will be conducted at three locations, each using 3 treatments: zero, intermediate, and full stover removal. We will measure soil organic carbon (SOC) changes and gas exchange. Research will also be conducted at the UMN’s Rosemount Research and Outreach Center (ROC) and on private farm fields in MN. Research at Rosemount will take place in two 20 ha fields with similar soil types, one managed as a conventional corn-soybean rotation; the other in a corn-soybean rotation, but with winter rye cover crop seeded by helicopter in late summer. Latent and sensible heat flux and net ecosystem exchange of CO2 will be measured by eddy covariance. Yield and ancillary soil, physiological and micrometeorological variables will also be measured for 4-years. Soil sampling for SOC analysis will be conducted biennially. Data will be used to test a model of rye production and water use (RyeGro). Field research will also be conducted at Rosemount MN and Arlington WI, supplemented by greenhouse research in St. Paul. Four treatments will be evaluated using a completely randomized design with 3 replications: (i) control, (ii) biochar, (iii) biochar plus manure, and (iv) manure. Biochar will be applied at 20,000 lb ac-1. Three other biochar treatments, derived from macadamia nut, wood pellet, and lump hardwood charcoal, will also be evaluated. Biochar production temperatures will be varied according to constant heating time and thermal time equivalency tests. Experiments will be conducted to examine impact of post-processing of biochar by thermally or chemically activation. All biochars will be analyzed for elemental composition, surface area, thermal stability, and CEC. Incubations will assess the impacts of biochar amendments on GHG production. For the greenhouse studies, 5 different specialty crops will be investigated with respect to biochar impacts on germination, growth, and uptake of volatile chemicals. Lab incubation experiments will be conducted to evaluate the inhibition of ammonium and nitrite oxidation rate due to the presence of free ammonia and free nitrous acid. Three different soils used for corn production in MN, IA, and eastern Canada will be examined. The methods will be adapted from procedures used to quantify nitrification inhibition kinetics in wastewater. Parameters obtained in the lab experiments will be incorporated into previously developed nitrification and N2O emissions models that account for both steps of nitrification, N2O production pathways, microbial N2O reduction, and gaseous diffusion. Plot experiments will be conducted over two consecutive growing seasons at the UMN ROC in Rosemount, MN in long-term research plots split into subplot treatments. Each main plot will first be randomly sub-divided by N rate so that each subplot will receive the same total N rate during the growing season, with N rate levels of 0, 7.5, 15, 20 and 25 g N m-2. Each N rate treatment will then be randomly sub-divided into two timing treatment sub-subplots consisting of (a) a single pre-plant urea application, or (b) two split post-plant urea applications. Soil-to-atmosphere N2O fluxes will be measured using chamber methods.