Sustainable Corn Stover Harvests. Bioenergy Feedstocks Symposium 12 January 2011 Champaign, IL

Transcription

1 Sustainable Corn Stover Harvests Bioenergy Feedstocks Symposium 12 January 2011 Champaign, IL 1

2 Residue in second year corn field Story County, IA 11 June 2010 Fall disc ripper Spring anhydrous Spring field cultivate 2009 corn yield 187 bu/ac 2

3 Residue survey used to gauge farmer view of stover Three geographies Central West South What is a typical crop rotation for the corn acres on your farming operation? Residue survey (Sept 2010) 528 farmers Are actively involved in farming Are primarily responsible for decisions concerning seed purchases Don t work for seed or chemical companies Planted at least 500 corn acres in

4 Many farmers view residue management as an increasing problem Over the past few years, would you say that managing corn residue has become: 4

5 Problems resulting from excess corn residue Seriousness Of Problems Resulting From Overall West Central South Excess Corn Residue (n=528) (n=116) (n=277) (n=135) Soil is slow to warm up Major problem/challenge 10% 6% 10% 10% Major+Somewhat problem/challenge 43% 24% 47% 38% Soil is slow to dry out Major problem/challenge 7% 3% 7% 9% Major+Somewhat problem/challenge 36% 21% 37% 41% Trash causing planting problems Major problem/challenge 7% 5% 8% 4% Major+Somewhat problem/challenge 29% 23% 32% 24% Disease or pest pressure Major problem/challenge 6% 3% 7% 8% Major+Somewhat problem/challenge 36% 22% 41% 30% Soil to seed contact Major problem/challenge 4% 3% 4% 5% Major+Somewhat problem/challenge 31% 22% 33% 27% 5

6 Residue management practices Summary Overall West Central South (n=528) (n=116) (n=277) (n=135) Changing field practices such as tillage or shredding 56% 47% 58% 51% % Using different tillage equipment 40% 33% 42% 36% % Mowing, shredding or chopping stalks 28% 22% 32% 16% % Making extra tillage passes 28% 15% 29% 32% % Tilling deeper 25% 16% 30% 15% Changing timing of field operations such as fall tillage 26% 9% 27% 30% Typically removing stover from cornfields, including grazing 20% 58% 17% 8% % Removing stover in % 36% 15% 6% Changing crop rotations 12% 16% 13% 8% Intentionally burning off residue 5% 3% 3% 10% In an effort to control corn residue over the past few years: 6

7 Residue management is an expense to farmers More than $20 $15.01 to $20 $10.01 to $15 $5.01 to $10 $5 or less Don't know Overall (n=285) Percent of Respondents Average $12.50 West (n=54) $11.40 Central (n=162) $12.95 South (n=69) $ ,000+ corn acres (n=116) $12.05 Irrigated (West) corn acres (n=49) $11.35 Continuous corn acres (n=219) $ Q.2f What would you estimate the additional cost per acre for these tillage efforts to manage corn residue? Please include labor, fuel, and equipment costs. Average reported cost is $12.50/ac, but wide range of estimates 7

8 Stover provides important services to the field Stover is required to maintain soil quality Reduces wind erosion Reduces water erosion Provides organic matter to soil Soil organic matter Enhances soil water and nutrient holding capacity Improves soil structure (less crusting, compaction and erosion) Promotes higher crop yields Stover harvests must not compromise these services 8

9 Stover project structure and scope Sustainable harvest Transport Storage Conversion Large scale joint work Individual research scale work Feedstock improvement Improved tillage, planting and harvest Biofuel production Improvement 9

10 Conservation planning tools can help guide stover harvests Tools like RUSLE, WEQ, and the Soil Conditioning Index are likely to be the most practical ways to predict safe removal rates. Andrews (2006) Factors that should be considered when removing residue include: Water* and wind erosion, accumulation of soil organic matter, water retention, chemical run off and wildlife habitat Andrews S (2006) Crop Residue Removal for Biomass Energy Production: Effects on Soils and Recommendations University of Nebraska Extension: Harvesting Crop Residues USDA NRCS (2010) Conservation practice standard 344: Residue management, Seasonal. ftp://ftp fc.sc.egov.usda.gov/nhq/practice standards/standards/344.pdf USDA NRCS Soil Quality Institute (2003) Interpreting the Soil Conditioning Index: A Tool for Measuring Soil Organic Matter Trends. Technical Note No *RUSLE2 includes sheet and rill erosion, but not ephemeral gulley or gulley erosion 10

11 Corn stover harvest fields Farms located west of Cedar Rapids, IA fields, 4,807 acres fields, 3,998 acres Average field 126 acres +/ 62 ac Average slope 4.1% Typical soil type Silty clay loam 18 corn corn fields 20 soy corn fields 2008 average grain yield 194 bu/ac 2008 average stover harvest 1.2 +/ 0.5 dry tons/ac 30 +/ 15% of total stover Bar = 25 miles Average field 105 acres +/ 43 ac Average slope 2.7% Typical soil type Silty clay loam 11 corn corn fields 25 soy corn fields 2009 average grain yield 191 bu/ac 2009 average stover harvest 1.7 +/ 0.6 dry tons/ac 47 +/ 18% of total stover 11

12 Grower interviews and RUSLE2/SCI Eager summer intern Field specific information RUSLE2 management file Soil Conditioning Index (SCI) at threshold Field stover requirement: The amount needed to keep Erosion (ER) and Organic Matter (OM) sub factors in the Soil Conditioning Index positive Soil loss 2.5 tons/ac Soil Conditioning Index 0.2 Erosion is rate limiting sub factor at threshold for this field 12

13 Example fields 218 Farm 218 Farm (corn bean rotation) 52 ac, Dinsdale silty clay loam (377B), Average slope 3.3% 2008 No till beans (57 bu/ac) 2009 Min till corn Fall fertilizer (145 UAN, variable P and K) Spring conditioning (rolling harrow) Mix of three hybrids (DKC59 64, DKC60 51 plus refuge) Pre & post emergent herbicides (Harness Xtra, Round Up ) Don s Farm Don s Farm (corn after corn) 103 ac, Dinsdale silty clay loam (377B), Average slope 2.9% 2008 tilled corn (192 bu/ac) 2009 tilled corn Fall shred stalks, chisel plow Fall fertilizer (150 anhydrous, 240 lb K 2 O) Spring finish (disc plus harrow) Mix of three hybrids (DKC63 42, 34F26, 33W84) Pre emergent herbicides (Harness Xtra/Atrazine) Side dress (47 lb UAN) 13

14 Harvest index estimated as a function of grain yield 80% 70% Harvest index vs. yield (2008 and 2009, n = 946, plant intactness rating 1 or 2) Green: 2008 Orange: 2009 Harvest index (grain mass/total above ground mass) 60% 50% 40% 30% 20% 10% 0% Yield (bu/ac) Source Harvest index Grain yield (bu/ac) Stover yield (dry tons/ac) RUSLE2 assumption Ty Barten (Monsanto) Weight difference 1.4 tons/ac Percent difference 25% 14

15 Are farmers and modelers seeing the same corn plant? Higher harvest index Healthier plants, decay starts later in year Higher planting density, more rind/pith Larger root balls, more roots (?) Planting 2 nd yr corn in Nebraska High planting density Rootworm protection Staygreen Corn borer protection 15

16 Benton County, Iowa harvest rate estimates Field stover requirements averaged 2.5 +/ 1.2 dry tons/ac across the 74 fields examined Corn yield required to remove 1 dry ton/ac corn stover Corn yield required for 1 ton/ac harvest (bu/ac) soy corn spring conditioning C C harvest alternating years C C harvest every year Average field slope (%) Average 2009 yield 191 bu/ac 2009 average slope 2.7% 2008 average slope 4.1% 16

17 Field prior to stover harvest 17

18 Raking Kuhn SR112 Speedrake, rake estimate 4 5% dirt in 2008 bales 18

19 Windrows at an oblique angle to corn rows 19

20 Deere 566/567/568 round balers 20

21 Vermeer 605 M cornstalk special 21

22 Bühler/Inland 2500 bale carrier Huge improvement over 2009, staging 86 bales/hr vs. 19 bales/hr in

23 2009 stover harvest actual vs. target RUSLE2 harvest target (bale/ac) Actual harvest rate (bale/ac) 4 fields over harvested 457 acres (26%) 5 fields within 0.5 bales/ac 574 ac (33%) 7 fields under harvested 731 ac (41%) SCI for most over harvested field Over harvested fields 4 of 6 lowest target rates Erosion = 1.1 tons ac 1 yr 1 23

24 Field 10 3 post baling residue images 24

25 Pre and post baling images of field dry tons/ac stover harvest Post combine (5 November) Post baling (12 November) 25

26 Post harvest field 26

27 Harvest vs. target 2008 and

28 Stover is currently harvested to support livestock Overall West Central Method Of Removing Stover From Fields (n=93) (n=43) (n=42) Baled [NET] 56% 14% 74% Removed in round bales 53% 14% 69% Removed in square bales 3% -- 5% Grazed by cattle 49% 91% 29% Chopped/cut up* 8% 2% 12% Silage* 8% 2% 12% On an overall basis: 70% of all baled stover was self baled, 30% hired a custom operator. An average of 4 bales were removed per acre. Method Of Determining How Much Stover To Remove Overall West Central From Fields (n=93) (n=43) (n=42) Enough to feed cows/animal nutrition 36% 56% 29% All possible/available 8% 2% 10% Guessed 7% 9% 7% Enough for cattle bedding 6% -- 10% All that could be raked 5% 2% 7% 28

29 Engineers are designing machinery for stover harvests New Holland HT 154 New Holland H5980 H5980 wider rake, short steel teeth with flexible mounts Less time to rake fields, larger windrows increased baling speed Raking rate: 14.2+/ 2.9 ac/hr in 2010 vs / 3.1 ac/hr in 2009 Required adjustment to avoid over harvesting stover

30 Jim Straeter s Cornrower

31 Bale sampling 31

32 Nutrient content of corn stover bales varied by year and field N 6.4 +/ 1.2 lb/bale P 2 O / 0.06 lb/bale K 2 O 4.0 +/ 0.73 lbs/bale 32

33 Power generation with corn stalks Delivered GHG content Corn stover 1 Coal 2 Natural gas kg +/ 0.7 CO 2 eq/mmbtu 94 kg CO 2 eq/mmbtu 53 kg CO 2 eq/mmbtu Cedar Rapids, IA February June Deere, ADM, Monsanto corn stover research project, stover LCA

34 Corn stalks used for bedding and power, nutrients recycled Amana, Iowa Feb 3 rd

35 Alkaline upgrading of corn stalks for cattle feed Ames, IA October 20 th 2009 DM digestion, % Untreated Treated % Improvement +10% +28% % +116% Option 1 Option 2 Option 1 Option 2 Option 3 On farm Processing Depot Pre treat and blend fibrous feedstocks with commodities Agricultural residues: corn stover, corn cobs, wheat straw Processing co products: DGS, CGF, distillers solubles, steep liquors Replace roughage (hay) and corn grain in diets Pre treatment can enhance fiber digestion, improving usable calories 30 50% Fully replace corn silage or hay, partially replace grain Favorable economics (better cost of gain) Data courtesy of Mike Cecava, ADM 35

36 Summary Conservation planning tools can help guide corn stover harvests Harvest rates will vary from field to field Requires management to organic matter and erosion target Fields with less slopes and greater organic matter input (higher yields, corn corn) are preferred for stover harvest (25 to 40% of fields in Iowa) In Eastern Iowa sustainable harvest rates are in the range of 1 to 2 dry tons ac 1 yr 1 Nutrient value will vary by year and location 36