Zara Clayton-Niederman, University of Arkansas, Center for Agricultural and Rural Sustainability

Transcription

1 Establishing a Methodology for Carbon Sequestration in Cotton Production in the US. Lanier Nalley PhD Department of Agricultural Economics Zara Clayton-Niederman, University of Arkansas, Center for Agricultural and Rural Sustainability Marty Matlock PhD Ag and Bio Engineering Kristopher Brye PhD Department of Crop Soils and Environmental Sciences With funding from Cotton Incorporated

2 Cotton LCA Case Study LCA Inventory Data were collected from the 15 largest cotton producing states County specific data were collected for over 400 counties or CRDs Using extension contacts over 50 production methods were identified across the US. County specific data included % irrigation Type of irrigation (furrow, CP, etc.) % breakdown of production type

3 Production Type Production types included No, Low, and Strip Tillage RR, Conventional, RRII. RRFLEX, etc. 8 or 12 row This allowed a county to be segmented by % irrigation, cotton variety, and tillage practice. State extension budgets which provide recommendations for farmers on application of pesticides, fertilizer, herbicide, defoliant, etc. were then used to calculate the carbon output by practice

4 Cotton LCA: Complexity Production Practice Type

5 Cotton LCA: Complexity Inputs

6 Carbon Equivalents and Uncertainty Carbon Equivalents From Literature Distributions Use for Monte Carlo Uncertainty Analysis

7 Carbon Equivalents Furrow 12 Row RRFLEX (1144) Chicot County Arkansas Fertilizer lb CE / lb a.i. lb C per acre Urea (46%N) 218lbs Phosphorus 60lbs Potassium 120lbs Herbicides Glyphosate Plus 6.1 pts Clarity 0.5 pts Gramoxone Extra 0.25pts Dual Magnum 1 pts Caparol 4L 0.75 pts Valor Sx 0.05 lbs Insecticides Centric 40WG pts Trimax pts Bidrin 8L 1 pts Pyrethroid pts Orthene 1 lbs Defoliants Drop SC 0.1 pts Finish pts Ethephon 1.6 pts Diesel Tractors 8.35 gals Self-Propelled 3.49 gals Irrigation 12gals Sum 537

8 CE by Production Practice and Input

9 Furrow 12 Row RRFLEX (1144) Chicot County Arkansas Carbon Equivalents Fertlizer lb CE / lb a.i. lb C per acre Urea (46%N) 218lbs Phosphurus 60lbs Potassium 120lbs Sulfur 10lbs 0 Boron 1lbs 0 Herbicides Glyphoshate Plus 6.1pts Clarity 0.5pts Gramoxone Extra 0.25pts Dual Magnum 1pts Caparol 4L 0.75pts Valor Sx 0.05lbs Insecticide Centric 40WG pts Trimax pts Bidrin 8L 1pts Pyrethroid pts Orthene 1lbs Defoiliant Drop SC 0.1pts Finish pts Ethephon 1.6pts Diesel Tractors 8.35gals Self-Propelled 3.49gals Irrigation 12gals Sum

10 Where does cotton stand relative to other crops in emissions per acre? Lb/Ac of Carbon Rice* Lb/Ac of Carbon Cotton BG/RR/Conventional Till/CP/ Conventional/Siltloam/Flood BG/RR/Conventional Till/Furrow/ Conventional/Clay/Flood BG/RR/Conventional Till/Furrow/ Conventional/Siltloam/StaleSeedbed BGIIRRFlex/SS/CP/ Conventional/ Siltloam/no-till BGIIRRFlex/SS/Furrow/ Clearfiled/Siltloam/Flood BGRR/SS/CP/ Hybrid/Siltloam/Flood RRFlex/SS/Furrow/ Clearfield Hybrid/Siltloam/Flood BGRR/Conventional/Furrow/ Zero Grade/No-till/Water Seeded BGIIRRFlex/SS/Furrow/Ridge/ Wheat Corn Sandy Siltloam/following rice Conventional/Loam/CP Clay/following rice Conventional/Loam/CP Sandy Siltloam/following other RR/Loam/Furrow Clay/following other Bt/RR/Loam/Furrow RR/Clay/Furrow Beans (Dry&Irr) Bt/Loam/Furrow RR/Dry RR/Furrow Sorghum RR/Border Loam/Center Pivot RR/CP Loam/Flood RR/Flood Loam,/Furrow Conventional/Dry Loam/Dry Conventional/Furrow Conventional/Border Double Beans Conventional/Flood RR/Dry RR/Furrow RR/Border RR/Center Pivot RR/Flood Conventional/Dry Conventional/Furrow Conventional/Border Conventional/Center Pivot Note: These estimates are from a scan level LCA from Arkansas. These estimates are only valid for Arkansas and have not had sensitivity analysis conducted on them.

11 Cotton s Footprint Carbon Emissions (lbs/acre)

12 Cotton s Footprint Carbon Emissions (lbs/lb cotton) Yield

13 Importance of Weather & Yield Carbon Emissions (lbs/lb cotton) 2007 Yield

14 Total Production and Carbon Equivalent of Upland Cotton

15 Cotton GHG Emissions LCA: Key Findings 1. Nitrogen Matters Fertilizer, N2O 2. Region Matters California Cotton is not the same as Florida Cotton 3. Yield Matters High outputs can outweigh high inputs 4. Assumptions, data and variability matter LCA s are more than just a number

16 Carbon Sequestration Emissions is only the first step in calculating total net emissions (Emissions Sequestration). While there is a deep literature base on emissions, sequestration estimation is much more nebulous. The following methodology was put together by a team of agronomists at the UofA and represents a best estimate of how the federal government may estimate sequestration for carbon policies

17 Carbon Sequestration The drivers of sequestration are: 1) Soil type 2) Tillage practice 3) Above and below ground biomass 4) Yield There may be other components to sequestration but these constitute the majority.

18 Carbon sequestration Soil This study looks at three types of: Clay, Sand, and Loam While theoretically an identical plant under identical growing conditions on different soils would sequester the SAME amount of carbon they would not RETAIN the same amount. Clay soils can retain more carbon than loam which can retain more carbon than sandy soils Our model indicates that soil type is the major driver of carbon sequestration

19 Carbon sequestration - Tillage This study analyzed the effects of three tillage types on carbon sequestration 1) No-till 2) Low-till 3) Conventional tillage Generally speaking, no-till is considered to be the most beneficial to the environment but it does have trade-offs for sequestration potential

20 Tillage- Above ground biomass Approximately 42% of cotton s above ground biomass is carbon based. To sequester this carbon in the soil it must be tilled under There is some leaching from the surface but minimal Thus conventional tillage introduces this carbon material to the soil at a higher rate than low-till and a much higher rate than no-till So, with regards to above ground biomass the more you till the more residue you introduce to potentially increase carbon sequestration levels.

21 Tillage- Above ground biomass Approximately 36% of cotton s below ground biomass is carbon based. No-till maximizes the amount of below ground carbon that can be sequestered because it does not introduce the below ground biomass to the surface like conventional tillage and to a smaller extent low-till Thus while conventional tillage is beneficial for potential sequestration it is detrimental for below ground sequestration potential So we have trade-offs between tillage practices

22 Model Parameters Soil- Clay has the highest retention potential sand the lowest Retention Rate of Sequestered Carbon by Soil Type Soil Type Min Mean Max Clay 80% 95% 100% Loam 60% 75% 100% Sand 30% 45% 70% Conventional tillage has the highest potential to sequester above ground carbon No-till has the highest potential to sequester below ground carbon Percent of Above Ground Biomass Carbon that can be Sequestered Tillage Type Min Mean Max No Till 5% 10% 15% Low Till 30% 50% 70% Conventional 50% 70% 90% Percent of Below Ground Biomass Carbon that can be Sequestered Tillage Type Min Mean Max No Till 40% 50% 50% Low Till 35% 45% 50% Conventional 33% 40% 45%

23 Sequestration Example Step 1. Find out the soil break down of each county: County Soil Type Percent of County Hockley Sandy Loam 50% Acuff or Portalas loam 25% Loamy Sand 25% Now classify this by our predetermined soil types: County Soil Type Percent of County Hockley Loam 75% Sand 25%

24 Sequestration Example Step 2. Classify tillage types by county: County Tillage Type Percent of County Hockley Low-till 90% Conventional 10% Step 3: Using the harvest index, yield, tillage type, soil type, shoot-to-root ratio, and adjusting for moisture loss we can calculate sequestration on a per acre basis.

25 Sequestration example State County Soil/Tillage Type Acres Texas Hockley Average County Emissions (lbs/acre) Sequestration (lbs/acre) Total Emissions/ Sequestration Wieght (%) Wieghted Average (lbs/acre) County Average Emissions/Seq. (lbs/acre) Loam/Low-till 143, Sand/Low-till 47, Loam/Conventional 15, Sand/Conventional 5, As illustrated above for Hockley county Texas, most counties will have multiple production practices some. Some will be net emitters and others net sequesterers We do NOT account for carbon sequestered in cotton lint, which is estimated at 54% carbon

26 Emissions Pounds Per Acre What s wrong with Mississippi?

27 Sequestration Pounds Per Acre

28 Net Sequestration Per Acre

29 Cotton In Arkansas In 2008 there were approximately 99,000 acres of dryland cotton harvested in Arkansas Using 2008 NASS county level data, a state level LCA model (Nalley and Popp) indicate that these acres were NET sequesters of carbon by roughly 19 million pounds. In 2008 there were approximately 521,000 acres of irrigated cotton harvested in Arkansas. The same model indicates that these acres were a NET sequesterer of carbon by roughly 117 million pounds.

30 Where does cotton stand in relative to other crops in NET sequestration per acre? Lb/Ac of Carbon Rice* Lb/Ac of Carbon Cotton BG/RR/Conventional Till/CP/ Conventional/Siltloam/Flood BG/RR/Conventional Till/Furrow/ Conventional/Clay/Flood BG/RR/Conventional Till/Furrow/ Conventional/Siltloam/StaleSeedbed BGIIRRFlex/SS/CP/ Conventional/ Siltloam/no-till BGIIRRFlex/SS/Furrow/ Clearfiled/Siltloam/Flood BGRR/SS/CP/ Hybrid/Siltloam/Flood RRFlex/SS/Furrow/ Clearfield Hybrid/Siltloam/Flood BGRR/Conventional/Furrow/ Zero Grade/No-till/Water Seeded BGIIRRFlex/SS/Furrow/Ridge/ Wheat Corn Sandy Siltloam/following rice Conventional/Loam/CP Clay/following rice Conventional/Loam/Flood Sandy Siltloam/following other RR/Loam/Furrow Clay/following other Bt/RR/Loam/Furrow RR/Clay/Furrow Beans (Dry&Irr) Bt/Loam/Furrow RR/Dry RR/Furrow Sorghum RR/Border Loam/Center Pivot RR/CP Loam/Flood RR/Flood Loam,/Furrow Conventional/Dry Loam/Dry Conventional/Furrow Conventional/Border Double Beans Conventional/Flood RR/Dry RR/Furrow RR/Border RR/Center Pivot RR/Flood Conventional/Dry Conventional/No-Till/Furrow Conventional/No-Till/Border Conventional/No-Till/Center Pivot Note: These estimates are from a scan level LCA from Arkansas. These estimates are only valid for Arkansas and have not had sensitivity analysis conducted on them.

31 Carbon Sequestration If your sequestered amount is larger than your emitted amount per acre than you have potential offsets to sell If your emissions are larger than your sequestration under the cap and trade policy you would have to purchase carbon permits from elsewhere Under the taxation system you would either be taxed on total carbon emitted or net (sequestration emissions) carbon emitted How much is carbon worth? Currently carbon is trading at $0.40 per ton If the Waxman-Markey Bill passes (Cap-and-Trade) carbon price is estimated to be $14.22 in 2010 Under the same scenario it is estimated at in 2050

32 Pounds of Carbon Sequestered Per Acre The Weighted Average of Net Sequestration (lbs/acre) by Crop in Arkansas Corn Dry Soybeans Irrigated Soybeans Dry Cotton Irrigated Cotton Rice Crop

33 Dollars per Acre How Much Is That Worth Today? Corn Dry Soybeans Irrigated Soybeans Dry Cotton Irrigated Cotton Rice Crop

34 Dollars per Acre How Much Is This Estimated To Be Worth If The Waxman Markey Bill Passes? Corn Dry Soybeans Irrigated Soybeans Dry Cotton Irrigated Cotton Rice Crop