2012 Annual Report
1a.Objectives (from AD-416):
To evaluate the use of biochar derived from corn stover or ethanol co-products as a means of stabilizing fall-applied N and to evaluate spring applications of N Serve as a way of further stabilizing fall-applied Nserve.
1b.Approach (from AD-416):
Laboratory incubation experiments will be conducted during the first 6 months of the study. The objectives of the laboratory component will be to determine the overall feasibility of our hypotheses under controlled conditions, and to determine which conditions (e.g. biochar mixing ratios and biochar types) to examine in the field. Different types of biochar (differing in feedstock and pyrolysis conditions) will be mixed with soil, both with and without N-serve® addition, followed by AA application. Rates of nitrification and N2O production will be monitored for 4- to 6-months under different temperatures using established procedures. The field experiment will be initiated in the fall of 2011 at an existing set of replicated research plots at the University of Minnesota’s Outreach, Research, and Education Park in Rosemount, MN and will be monitored through the following growing season (2012). The field experiment will be repeated in 2012-2013 in order to confirm the findings. Pending results of the lab studies, the following experimental treatments will be established in the field plots, with all treatments receiving fall-applied AA, plus: 1. no amendments; 2. fall-applied N-serve®; 3. biochar incorporation (prior to AA application); 4. biochar incorporation + fall-applied N-serve® 5. fall-applied N-serve® + spring-applied N serve®, and 6.biochar incorporation + fall-applied N-serve® + spring applied N-serve®. AA will be applied at rates based on University of Minnesota recommendations for corn production. N-serve® will be added at the time of fall AA application. For treatments (5) and (6), additional N-serve® in spring will be applied at the same location as fall application. Since the effectiveness of N-serve® depends on matching its placement with the location of the AA band, RTK (real time kinematic) guidance systems will be used for both the fall fertilizer injection and the spring cultivation for these treatments. Biochar will be broadcast and incorporated at fall tillage at optimal rates determined in the lab study. Porous cup lysimeters will be installed below the rooting zone for collection of water samples to monitor nitrate leaching. Gas flux chamber techniques will be used to measure N2O emissions. Soil concentrations of ammonium, nitrite, and nitrate will be determined periodically. Corn will be planted and grain yields determined.
A variety of activities and experiments have been conducted under this project. To date we have conducted (i) laboratory biochar amendment experiments to determine if adding biochar to soil can slow down nitrification and also reduce nitrate leaching and nitrous oxide emissions, (ii) laboratory N-serve amendment experiments to determine if adding biochar to soil together with the nitrification inhibitor N-Serve™ will have beneficial effects on nitrate leaching and nitrous oxide emissions, (iii) laboratory ammonia sorption experiments to determine if biochar added to soil can help to stabilize fall-applied anhydrous ammonia via strictly physical absorption (or “sorption”), (iv) a field experiment in St. Paul, MN using soil cores incubated over-winter to compare nitrate leaching and nitrous oxide emissions using fall-applied anhydrous ammonia (AA) alone, AA plus fall-applied N-Serve™, AA plus biochar, and AA plus biochar plus fall-applied N-Serve™, and (v) a field experiment in Rosemount, MN to compare nitrate leaching and nitrous oxide emissions using fall-applied AA alone, fall-applied AA plus fall-applied N-Serve™, fall-applied AA plus fall-applied N-Serve™ plus spring-applied N-Serve™, and spring-applied AA plus spring-applied N-Serve™. All of these experiments are continuing. This progress contributes to meeting Objective 3 of our NP212 Project Plan which is to “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).”