Pendell, Dustin (Kansas State Univ., 332C Waters Hall, Manhattan, KS, 66506-4011; Phone: 785-532-4438; Email: dpendell@agecon.ksu.edu)

An Economic Feasibility Analysis of Manure Applications and No-Tillage for Soil Carbon Sequestration in Corn Production

D. L. Pendell*, J. R. Williams, C. W. Rice, R. G. Nelson, S. B. Boyles

Background: Interest is increasing in carbon sequestration due to potential climate changes resulting from accumulations of atmospheric carbon dioxide and other greenhouse gases. Potential regulation of greenhouse gas emissions in addition to consumer interest to purchase environmentally friendly products will provide incentives for developing efficient sequestration techniques. One opportunity for some industries to reduce their share of greenhouse gases is to pay another industry, like agriculture, to reduce its emissions and to sequester carbon from the atmosphere. The economic feasibility potential of using beef manure applications and a no-tillage versus commercial nitrogen and conventional tillage for continuous corn production to sequester soil carbon is evaluated. Objectives: The primary objective of this study was to determine the cost of carbon sequestration or the value of carbon credits needed for implementing carbon-sequestering strategies in continuous corn production. Specific study objectives included: 1) Estimate net returns distribution for each system using nine years of annual prices and yields, 2) Calculate C sequestration rates from historical soil test data for each system, 3) Identify the amount of carbon dioxide released to the atmosphere due to field operations and the production of inputs in order to create a carbon balance sheet for each cropping system, 4) Identify the economically preferred systems, and 5) Determine the monetary value of a C credit required to entice producers to alter management strategies to enhance carbon sequestration. Data and Methods: Enterprise budgets were used to estimate net returns under two different tillage systems and three different fertility treatments. Carbon release values from direct, embodied, and feedstock energy for the fertilizers and chemicals applied were estimated. The estimates of C emissions were paired with soil C data to calculate annual net C sequestration. The value of a C credit in $/metric ton/year and $/hectare that was needed to make the returns from systems which sequestered more carbon equivalent to other systems which had higher net returns, but lower carbon sequestration rates were derived. Results: The analysis indicates that the highest net return was obtained from the system using no-till and ammonium nitrate. The second highest return was received from the system using no-till and manure. No-tillage had higher net returns than conventional tillage for both ammonium nitrate and manure. A comparison of net returns by nitrogen source indicated that for both conventional tillage and no-tillage, returns were higher for systems using ammonium nitrate than they were for systems using manure. When soil carbon data across the systems were compared, two results were found. No-tillage had higher soil carbon sequestration rates than conventional tillage. Systems, which used manure as a nitrogen source, had both higher soil carbon and net carbon sequestration rates than systems using ammonium nitrate. These conclusions were also true when net carbon, which accounts for emissions from the production and application of inputs was considered. The economic analysis indicates some incentive would be required to entice producers to adopt manure fertilization strategies as a means of sequestering carbon. The value of a carbon credit required to switch from NH₄NO₃ to manure using conventional tillage at a 168 kg/ha application rate is $37/metric ton/year. A carbon credit of $374/metric ton/year would be required to switch from NH₄NO₃ to manure at a

168 kg/ha application rate using no-tillage.