Soil Carbon Sequestration in Agriculture Scott Staggenborg and Charles W. Rice Department of Agronomy K-State Research and Extension
Strategies to Reduce Atmospheric CO 2 Strategies Identify sinks and sequestration rate Reduce fossil fuel consumption Improve efficiency Renewable energy sources Aquatic Terrestrial Soils Plants Geologic
Soil C sequestration potential of different US land Categories (% of 322 MMT C/yr) **
Improved Agricultural Practices Conservation buffers Conservation tillage CO 2 Cover crops Soil organic matter Improved rotations
Climate energy Soil Type Management CO 2 product Soil Organic Matter (Humus)
Crop Management Strategies for C Sequestration Develop Crop Management Programs that:
Enhancing C Input – Fertility C-C NF 1991 -1999
Enhancing C Input – Crop Selection
Crop Management Strategies for C Sequestration • To increase soil carbon levels, we need crop rotations that reduce fallow periods. • Especially rotations with fallow periods during the summer when temperatures result in maximum soil respiration rates.
Enhancing C Input – Intensifying Rotations
Crop Management Strategies for C Sequestration Eastern Colorado
Crop Management Strategies for C Sequestration Develop Crop Management Programs that:
Why Tillage – Eliminate soil compaction – Control weeds – Eliminate residue • Harbor insects and diseases • Tie up fertilizer N • Barrier for herbicide – What hard working people do • Sense of accomplishment • Cleansing operation • Why not? Because it causes soil erosion and reduces soil organic matter
Enhancing C Input – Tillage C-C NF 1991 -1999
Reducing Loss – Reducing tillage
Enhancing C Input – Tillage NE W-F 1970 -1990
Soil organic C after 2 and 12 y of CRP in Nebraska (Baer, Kitchen, Blair, and Rice) 0. 4 Tons/a/y
Water Holding Capacity Soil Biodiversity Soil Quality Soil Structure Soil Organic Matter Nutrient Reserves Root growth Crop Yield Lal, Kimble, and Follett 1997 Plant Biomass
Carbon Credits/Trading • Carbon reduction – C reduction at point of emissions – C reduction by sequestration • Is it cheaper to buy a credit than control emissions?
What is needed • • Sellers of C credits: Land managers Aggregator Buyers Monitoring/Verification
Examples of feasibility and pilot projects on soil carbon sequestration Region Land Use Land management change Saskatchewan, Canada Cropland Direct seeding / cropping intensification Pacific Northwest, USA Cropland Direct seeding / cropping intensification Midwest Iowa, Kansas Cropland Grass planting No-till New grass plantings Oaxaca, Mexico Crop / natural fallow secondary forest Fruit tree intercrops with annual crops / Conservation tillage Pampas, Argentina Cropland Direct seeding Kazakhstan Cropland Agriculture to grassland Izaurralde (2004)
U. S. Central Region for CCX® Soil Offsets for no-till or grasses Offsets for grasses only
Kansas MRLAs and Carbon Pilot Counties
Tillage Equipment • Full width inversion – – – • Moldboard plow Chisel plow Field cultivator Tandem disk Offset disk Row crop cultivator • Okay to use – – – No-till/ridge-till planter No-till drill Rolling harrow Subsoiler/ripper Anhydrous applicator Manure knife applicator General Guideline: After the implement has been through the field, there must still be a substantial amount of surface residue present and the soil disturbance must not be full width. If use of the implement would require that a leveling or smoothing activity follow, it would probably result in too much soil disturbance.
Mechanics of Ag Offset Aggregation in CCX® CCX - issues offsets to aggregator’s registry account - commissions verifiers documentation offsets Aggregators - accepts initial registrations from producers - assembles annual attestations of activities from producers - receives offsets into CCX registry account from - executes sales on CCX trading platform on behalf of growers - manage multi-grower reserve account documentation sales proceeds Individual Growers - register; undertake actions as per 4 -year contract; sign annual attestations; allow access to CCX verifiers; ultimate owner of offsets
2004 Carbon Offset Prices
Consortium for Agricultural Soil Mitigation of Greenhouse Gases • To provide the tools and information to successfully implement soil carbon sequestration so that – the accumulation of greenhouse gases is lowered in the atmosphere, – while providing income and incentives to farmers and improving the soil. Kansas State University Iowa State University Montana State University Ohio State University Texas A&M University Colorado State University Michigan State University of Nebraska Purdue University Pacific Northwest National Labs
Questions?
Potential of U. S. Cropland for C Sequestration, Fossil Fuel Off-set, & Erosion Control Lal et al. , 1999
Soil Sampling for Measuring Soil C • Soil C storage depends on soil area and thickness or mass – Report on volume basis • Need to sample: – Laterally across the landscape to account for spatial variability due to: • • topography erosion soil mapping units management (tillage, inputs). – Vertically through the profile to account for • horizonation, tillage, residue and root inputs
Variability of soil C (Mg ha-1) for an agricultural site Sampling scheme Mean SD CV% n† Grid 1 48. 36 3. 94 8. 2 25 Grid 1 47. 84 3. 61 7. 5 25 Grid 1 47. 83 2. 77 5. 8 25 Average 48. 01 3. 44 7. 2 Composit 48. 47 e 1 0 0 1 Composit 44. 65 e 2 0 0 1 Composit 46. 66 e 3 0 0 1 Average 1. 91 4. 1 46. 59
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