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Soil Carbon Sequestration: Long-term Effect of Tillage and Rotations Charles W. Rice and Karina Fabrizzi Kansas State University October 28-30, 2008 1 Global economic mitigation potential for different sectors at different carbon prices 7 GtCO 2-eq 6 5 4 3 2 Non-OECD/EIT EIT OECD World total 1 Energy supply 0 00 US$/tCO2-eq <1 <5 0 <2 0 00 <1 <5 <2 0 0 Transport Buildings Industry Agriculture Forestry Waste IPCC, 2007 Agriculture • A large proportion of the mitigation potential of agriculture (excluding bioenergy) arises from soil C sequestration, which has strong synergies with sustainable agriculture and generally reduces vulnerability to climate change. • Agricultural practices collectively can make a significant contribution at low cost – By increasing soil carbon sinks, – By reducing GHG emissions, – By contributing biomass feedstocks for energy use IPCC Fourth Assessment Report, Working Group III, 2007 Agriculture • Cropland – Reduced tillage – Rotations – Cover crops – Fertility management – Erosion control – Irrigation management • Rice paddies – Irrigation – Chemical and organic fertilizer – Plant residue management Rice fields in The Philippines • Agroforestry – Improved management of trees and cropland No-till seeding in USA Maize / coffee fields in Mexico Agricultural Management Strategies for C Sequestration Develop Agricultural Management Programs that: Enhance C Inputs Reduce C losses Crop Management Tillage Crop Selection Fallow Management Crop Rotations Climate Sunlight Soils Management CO2 Harvestable Yield Soil Microbial Activity Soil Organic Matter (C) Potential C sequestration in U.S Strategies Decreasing tillage intensity Mg C ha-1 yr-1 Management practices Reduced tillage, no-tillage, mulch tillage 0.24-0.40 High residue crops, applications of manure and biosolids, erosion Increasing amount of crop control, irrigation, integrated pest residue return management, precision agriculture Use of winter cover crops 0.1-0.3 Summer fallow elimination 0.1-0.3 Fertilizer management Perennial vegetation CRP 0.05-0.15 0.3-0.7 Lal et al., 1999, Post et al.,2004 Corn production in NE Kansas • Continuous corn • 168 kg N/ha • Tillage Systems – No-tillage – Conservation tillage (Chisel-disk) • 15 year analysis 8 Soil C stocks after 18 years 0-5 * NT CT 5-15 15-30 30-60 * 0-60 * 0 20 40 60 80 100 120 Nicoloso et al., 2008 9 Tillage effects on soil organic C by depth, Minnesota: 14 y continuous corn Mg C/ha/cm Depth No-till Plow 0.7.5 4.49 3.89 7.5-15 4.94 4.66 15-30 3.51 3.17 30-45 2.45 1.48 ** 0-45 (Mg/ha) 160 133 ** ** Huggins et al., 2007 10 -1) SOC levels (Mg C ha E O A Change in management Years of cultivation Soil C sequestration rates for 15 years (Mg C/ha/y) Depth Fertilizer N Fertilizer N Tilled No-till Manure N Tilled Manure N No-till cm 0-5 0-15 0.161 0.254 0.351 0.497 0.393 0.792 1.182 1.402 0-30 0.336 0.717 0.839 1.387 0-60 0.146 1.325 0.733 1.141 • NT > Tilled, but tilled had some increase • Added C (manure) is less conserved in tilled • What is baseline? Nicoloso et al., 2008 12 -1) SOC levels (Mg C ha E D O C A Change in management Years of cultivation Net effect of NT for 15 years NT (0-15y) –T (0-15y) Depth No N 0.5 Fertilizer N cm 0.5 Fertilizer N Manure N Manure N Mg/ha/y 0-5 0-15 0.187 0.182 0.450 0.371 0.190 0.243 0.468 0.402 0.789 0.610 0-30 0.174 0.311 0.381 0.417 0.548 0-60 -0.443 -0.191 1.179 0.961 0.408 Nicoloso et al., 2008 14 Carbon sequestration rate (C rate) expressed in equivalent mass (Mg C/ha/y) to a 30 cm depth except for Hayes (15 cm) Location Rotation Duration CT RT NT Hayes Wheat-Sorg-F 37 y 0.008 0.020 0.055 Parson Sorg-Soy 20 y 0.234 0.370 0.420 Ashland Average 29 y 0.269 0.346 0.384 Tribune Wheat-Sorg-F 15 y -0.570 -0.503 -0.392 Fabrizzi, 2006 15 SOC using NT or RT (Mg C ha-1 ) at 0-30 cm 60 SOCNT = 1.14x - 4.90 R2 = 0.76 55 1:1 Line SOCRT =1.08x - 3.14 R2 = 0.67 50 45 40 Ashland RT Parsons NT Parsons RT Hays NT 35 Ashland NT Tribune RT Tribune NT Hays RT 30 30 35 40 45 50 55 60 SOC using CT (Mg C ha-1) at 0-30 cm Intergovernmental Panel on Climate Change (IPCC): 1.1 for CT to NT 16 West and Post (2002): 1.16 for CT to NT Fabrizzi, 20065/24/2017 Carbon sequestration rate (C rate) expressed in equivalent mass (Mg C/ha/y) to a 15 cm depth as a function of N rate (kg N/ha/y) located Hayes, Kansas, USA Rotation Duration 0N 22 N 45 N 67 N Wheat-Sorg-F 37 y 0.007 0.012 0.035 0.057 Fabrizzi, 2006 17 Carbon sequestration rate (C rate) expressed in equivalent mass (Mg C/ha/y) to a 30 cm depth for Manhattan, KS USA Rotation Continuous Soybean 0.066 Continuous Sorghum 0.292 Continuous Wheat 0.487 Soybean - Wheat 0.510 Soybean - Sorghum 0.311 Fabrizzi, 2006 18 Conservation of Soil Carbon H2O O2 Plant characteristics Microbial composition and activity Hierarchy of importance Temperature Organic C Substrate quality Clay Biological factors Physical Protection Disturbance Organics Mineralogy Clay Chemical CO2 • Fungal Role (18:2w6 biomarker) • Significant tillage X residue interaction (p<0.05) 0.08 Mole Fraction a 0.06 b c 0.04 c* 0.02 0 CT + No R CT + Residue NT + No R NT + Residue Frey et al. (1999) found greater fungal networks optically in NT as compared to CT for the same soil. White and Rice, 2007 Tillage = Higher disturbance CO2 No-Till = Lower disturbance CO2 Plant C Fungi Fungi Microaggregates SOM Soil Macroaggregate White and Rice, 2007 SOM Soil Macroaggregate 80 YMollisol = 1.48 SOC - 8.2 R2 = 0.9245 60 (g 100g -1 soil) Amount of macroaggregates 70 YVertisol = 1.56 SOC - 2.83 50 R2 = 0.1292 40 30 20 YOxisol = 0.58 SOC - 6.9 10 R2 = 0.3344 0 0 10 20 30 40 -1 SOC (g C kg ) Fabrizzi, 2006 50 60 70 Gaseous Emissions Environmental Services Microbial Activity Soil Structure Water Soil Biodiversity Soil Organic Carbon Nutrient Cycling Erosion & Availability Plant Growth Yield Sustainability No-Tillage Cropping Systems Conservation Agriculture •Restores soil carbon •Conserves moisture •Saves fuel •Saves labor •Lowers machinery costs •Reduces erosion •Improved soil fertility •Controls weed •Planting on the best date •Improves wildlife habitat Summary • Soil C sequestration – Need to examine the system • Less disturbance • Organic C inputs – No-tillage must be combined with residues • Residue removal in no-till may be worst than tillage with residue • Agricultural soil C sequestration – Keeps land in production in some cases – In many cases increases profitability for the farmer – Provides other environmental benefits to society • Soil and Water quality (less runoff, less erosion) – May help adapt to climate change as well as mitigate Chuck Rice Phone: 785-532-7217 Cell: 785-587-7215 [email protected] • Websites www.soilcarboncenter.k-state.edu/ K-State Research and Extension Treatment Rate (Mg C/ha/y) State 0.073 0.117 0.229 Eastern Colorado NT (corn) NT 150 N Fert 0.80 NE Kansas Rotations 0.764 0.605 0.624 SC KS 0.80 NE Eliminate summer fallow CRP Scenario 3-year system 4-year system Continuous cropping CT - NT wheat CT - NT sorghum CTsorg/NTwheat to NT sorg/wheat 27 5/24/2017