Performance of Organic Farming Systems and Implications on Climate Change

Erin Silva, University of Wisconsin

March 5, 2013

http://www.extension.org/organic_production

Erin Silva, University of Wisconsin

Performance of Organic Farming Systems and Implications on Climate

Change

Erin Silva and Janet Hedtcke

UW-Madison, CIAS and Agronomy Dept.

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The Wisconsin Integrated Cropping Systems Trial

Feb 22, 2013 4Organic Farming Conference, La Crosse, WI

Arlington site

Wisconsin’s organics tops the national ranks

• #1 for total organic livestock

• # 1 for field crop acreage

• #1 for total organic milk cows (22% of USA total)

• #2 in organic milk sales (64% of organic sales)

• #2 in organic farms (n=1159 farms)

• # 10 in vegetables

• Organic dairy and livestock farms drive market for organic feed

Source: UW-Madison CIAS/DATCP 2012 status report

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WICST was born in 1989

Two locations:

• Arlington (well drained silt loam soils)

• Lakeland (more-poorly drained silt loam soils)

Over 20 years of data summarized:

• from 1992 to 2012

•Trends emerging•Economics

•Soil carbon

•Yield trends

•Weed seed

6

WICST: Lakeland site

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Cash-grain systems

7

Continuous corn Strip-till corn-soybean Organic grain

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Dairy (forage-based) systems

8

Conventional Alfalfa Organic forage Managed grazing

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Effect of weed pressure on corn yield

Wet Springs(May + June >10” rain)

Normal Springs

ARS LAC ARS LAC|--------------------------bu/a-------------------------------|

Conventional (min-tillcorn-soybean)

160 137 173 132

Organic(3-yr grain) 115 103 167 124

Org:conv 72% 76% 96% 94%

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Effect of weed pressure on soybean yields

Wet Springs(May + June > 10” rain)

Normal Springs

ARS LAC ARS LAC|--------------------------bu/a---------------------------|

Conventional (min-till corn-soybean)

48 57 57 53

Organic(3-yr grain) 38 44 54 49

Org:conv 79% 76% 95% 92%10eOrganic Webinar

11

30’ rotary hoe or tine weedercan do ~ 30 acres/hr

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Corn yields in extreme weather yrs

0

50

100

150

200

250

2008 (flood) 2012 (drought)

Bu

/acr

e

cont. corn

strip-till corn-sb

conv. dairy

organic grain

organic dairy

aa

b

a

b

c

x

y

xy

zz

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Rodale

• Corn in the legume-based (left) and conventional (right) plots six weeks after planting during the

• 1995 drought. The conventional corn

• is showing signs of water stress.

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• Rodale -Organic corn yields were 31% higher than conventional in years of drought

• Or

14

Organic

Conventional vs. Organic Corn Yield Trends

0

50

100

150

200

250

0 1 2 3 4 5 6 7 8

Yie

ld,

bu

/a

Cycle

Conventional Corn

Organic Corn-in 3-yr grain system

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Conventional vs. Organic Corn Yield Trends

0

50

100

150

200

250

0 1 2 3 4 5 6 7 8

Yie

ld,

bu

/a

Cycle

Conventional Corn

Organic Corn- in 3-yr forage system

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Conventional vs. Organic Soybeans

0

10

20

30

40

50

60

1 2 3 4

Yie

ld,

bu

/a

Cycle

ConventionalOrganic

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Conventional vs. Organic Alfalfa

0.0

1.0

2.0

3.0

4.0

5.0

6.0

1 2

Yie

ld,

t d

m/a

Cycle

Conventional

Organic

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Base Gross Margins (GM)

• GM = Crop revenue – variable costs

• Grain priced at harvest; hay priced in winter

• Gov’t payments included

• Feed-grade organic premiums included

• Systems scaled up to farm size– 1200 acres for conventional grain farms

– 600 acres for organic grain farm

– 150 acres of conventional and organic forage farms

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Historic GM of grain systems

0

50

100

150

200

250

300

350

400

450

Conv. min-tillcorn-sb

Organic grain(c-sb-w)

Conv. min-tillcorn-sb

Organic grain(c-sb-w)

ARL (1992-2009) LAC (1992-2002)

$/a

cre

Org premium

Gov't payment

Base GM

a

b

x

y

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Historic GM of forage systems

21

0

50

100

150

200

250

300

350

400

Convent.Forage

Organicforage

Convent.Forage

Organicforage

ARL (1992-2009) LAC (1992-2000)

$/a

cre

Org premium

Gov't payment

Base GM

a

by

x

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Corn and soybean feed-price trends (at harvest)

0

10

20

30

19

96

19

98

20

00

20

02

20

04

20

06

20

08

20

10

20

12

$/b

u

organic soy

conv. soy

22

0

5

10

15

20

19

96

19

98

20

00

20

02

20

04

20

06

20

08

20

10

20

12

$/b

u

organic corn

conv. corn

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Fertilizer cost in corn phase at ARL ($/acre)

23

$-

$50

$100

$150

$200

$250

$300

conventional (c-sb)

organic (c-sb-w)

PEPs corn grain

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Corn seeding cost at ARL ($/acre)

0

20

40

60

80

100

120

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

$/a

cre conv

organic

PEPs, grain

24

reseeded

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Soybean seeding cost at ARL ($/acre)

0

10

20

30

40

50

60

70

80

90

100

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

$/a

cre

conv

organic

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Total expense in grain systems (ARL)

0

50

100

150

200

250

300

350

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

$/a

cre

conv. grain

organic grain

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0

50

100

150

200

250

300

350

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

$/a

cre

conv. forage

organic dairy

Total expense in forage systems (ARL)

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Gross margins in 2000 decade-ARL

0

100

200

300

400

500

600

700

800

2002-2006 2007-2011

$/a

cre

Era

cont corn

strip-till corn

conv. dairy

organic grain

organic dairy

Era (E): p<0.0078System (S): p<0.0001E*S: p<0.0001

28

deef

ff f

a

b

c cd

de

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Soil Organic C changes over 20 yrs-ARL

-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

cont corn no-till c-sb org c-sb-w conv alfalfa org alfalfa pasture

Ton

s C

/a in

3 f

tp

rofi

le

a

b b

b

b

c

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Soil C inputs on WICST

ARL (‘92-’09) LAC (‘92-’02)

System lbs C/acre-1

Cont. corn 5390 3301

Min-till corn-sb 4081 3324

Org grain (c-sb-w) 3038 2297

Conv. Forage 6075 6353

Organic Forage 6377 7145

Pasture with managed grazing

5380 5548

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RUSLE2 Soil loss estimates† (18-yr avg, ARL)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

cont corn no-till c-sb org c-sb-w conv alfalfa org alfalfa pasture

Ton

s/ac

re

† assuming 4% slope, 150 ft run, contours

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N2O emissions/unit of N harvested-ARL

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C and N changes in other Long-Term Studies

• LTAR (Iowa) - Total nitrogen increased by 33 percent in the organic plots

– higher concentrations of carbon, potassium, phosphorous, magnesium and calcium

– results suggest that organic farming can foster greater efficiency in nutrient use and higher potential for sequestrating carbon

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• Rodale FST - in both organic and conventional systems, the highest overall GHG emissions were caused by soil processes fueled by nitrogen fertilizer, compost, and crop residues

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Rodale FST

• Organic system uses 45% less energy –mainly from not allowing conventional fertilizers

35

• Demand for non-renewable energy resources of the farming systems in the DOC experiment (1985–1998) per hectare and year (columns) and per kg dry matter (DM, line)(Nemecek et al., 2011)

36

LTRAS (California)

37http://asi.ucdavis.edu/programs/rr/research/carbon-sequestration-and-soil-organic-carbon

Conclusions

• Yields: Org:Conv >90% when weeds controlled

• Organic yields better than continuous GM corn in extreme weather years

• Organic yields similar to rotated GM corn in extreme weather years

• Yield trends– Corn increased at 2.5 bu/a/yr (same for organic and conventional)

– Soybeans had slight gain at 0.2 bu/a/yr (same for organic and conventional)

– Alfalfa –no real trend yet

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Conclusion (cont’d)

• Profitability: organic >conventional– Gross margin higher in last 5 yrs. vs. previous 5 yr

– Large part of the profitability is coming from strong and steady premiums (in this study feed premiums)

– Inputs (seed, fuel, and nutrients) are driving up expenses, often near to the cost of conventional inputs

• Ecosystem Services– All systems losing carbon other than pasture

– Expand rotation with alfalfa can reduce soil loss

– GHG lower under rotations but not necessary due to organic management

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