Comparison of Soil Organic Comparison of Soil Organic Carbon Stocks Between Carbon Stocks Between

Residential Turf Grass & Native SoilResidential Turf Grass & Native Soil

Richard V. Pouyat, Ian D. Yesilonis, and Richard V. Pouyat, Ian D. Yesilonis, and Nancy E. GolubiewskiNancy E. Golubiewski

• Residential: 40% of urban areas Residential: 40% of urban areas (Nowak et al. 1996)(Nowak et al. 1996)

• 40 million acres of lawn in 40 million acres of lawn in conterminous USA (Milesi et al., conterminous USA (Milesi et al., 2005)2005)

• 3 times more than acreage of 3 times more than acreage of largest irrigated crop (corn)largest irrigated crop (corn)

LIFE ZONELIFE ZONE AREA (x10AREA (x101212 mm22)) C Density (kg mC Density (kg m22) Soil C (x10) Soil C (x101515g)g)

Temperate forestTemperate forestTemperate forestTemperate forest----warmwarmwarmwarm 8.68.6 7.17.17.17.1 61.161.1

Temperate forestTemperate forest----coolcool 3.43.4 12.712.7 43.243.2

Cool temperate steppeCool temperate steppe 9.09.0 13.313.3 119.7119.7

Warm desertWarm desert 14.014.0 1.41.4 19.619.6

Cultivated landCultivated land 21.221.2 7.97.9 167.5167.5

WetlandsWetlands 2.82.8 72.372.3 202.4202.4

TOTAL WORLDTOTAL WORLD 1500(±20%)1500(±20%)

Adapted from Post et al. (1982) and Schlesinger and Andrews (2000)Adapted from Post et al. (1982) and Schlesinger and Andrews (2000)

Urban landUrban land 7.77.7 10.010.0 1.3 +1.3 +

Temperate thorn steppeTemperate thorn steppe 3.93.9 7.67.6 29.629.6

Boreal forestBoreal forest----wetwet 6.96.9 19.319.3 133.2133.2

Residential turf grassResidential turf grass 14.414.4 ??

*Milesi et al. 2005*Milesi et al. 2005

??

SIMILARITY?SIMILARITY?

BaltimoreBaltimore PhoenixPhoenix

URBAN LAND USE CHANGE?:URBAN LAND USE CHANGE?:1.1. Disturbance (initial, post-develop.)-Disturbance (initial, post-develop.)-

SOCSOC

2.2. Introduction of impervious surfacesIntroduction of impervious surfacesSOCSOC- - low, very slow changelow, very slow change

3.3. Introduction of horticultural Introduction of horticultural management (supplements)- management (supplements)- SOCSOC

4.4. Environmental change Environmental change (biophysical)- (biophysical)- SOCSOC

• $10.4 billion in USA$10.4 billion in USA

• Range of fertilizer rates:Range of fertilizer rates:Golf courses, Golf courses,

athletic fields—490 athletic fields—490 kg hakg ha-1-1 yr yr-1-1

Residential lawns—Residential lawns—50-145 kg ha50-145 kg ha-1-1 yr yr-1-1

• 16 million kg pesticides 16 million kg pesticides applied yrapplied yr-1-1 (Aspelin, (Aspelin, 1997)1997)

• Irrigation use?Irrigation use?

TURFGRASS MAINTENANCETURFGRASS MAINTENANCE

1.41.4

2020

TimeTime EdaphicEdaphic Cultivation Urban Cultivation Urban

BorealBorealCool Temperate SteppeCool Temperate SteppeCool Tropical ForestCool Tropical ForestMoist Tropical ForestMoist Tropical ForestWarm Temperate ForestWarm Temperate ForestWarm DesertWarm Desert

CCdd Urban Range at Urban Range at EquilibriumEquilibrium

Pouyat et al. (2001) & Pouyat et al. (2003)Pouyat et al. (2001) & Pouyat et al. (2003)

Agricultural Agricultural ConversionConversion

Urban Urban ConversionConversion

Global Range at Global Range at EquilibriumEquilibrium

Turf grass?Turf grass?Milesi et al., 2005Milesi et al., 2005

OBJECTIVES:OBJECTIVES:

1.1. Compare residential turf grass vs. native Compare residential turf grass vs. native SOC in Baltimore, MD and Denver, CO areasSOC in Baltimore, MD and Denver, CO areas

• Climatologically distinct regionsClimatologically distinct regions

• Compare residential turf grass vs. native Compare residential turf grass vs. native cover types (0.2 and 1 m depth)cover types (0.2 and 1 m depth)

• Field collected data, NRCS Soil database, Field collected data, NRCS Soil database, and data from literatureand data from literature

2.2. Estimate net effect of urban land-use change Estimate net effect of urban land-use change on SOC densities in both metropolitan areason SOC densities in both metropolitan areas

• Calculate SOC densities on area weight Calculate SOC densities on area weight basis (including impervious areas)basis (including impervious areas)

• Pre-urban, agriculture, and post-urban Pre-urban, agriculture, and post-urban landscapeslandscapes

EXPECTED RESULTS:EXPECTED RESULTS:

1.1. SOC densities of native soils will SOC densities of native soils will differ more than for residential soilsdiffer more than for residential soils

2. Net differences between pre- and 2. Net differences between pre- and post-urban SOC densities will be post-urban SOC densities will be positive in arid shortgrass steppe positive in arid shortgrass steppe (Denver) and negative in mid-(Denver) and negative in mid-Atlantic hardwood deciduous forest Atlantic hardwood deciduous forest (Baltimore)(Baltimore)

1 m DEPTH SOIL CORES1 m DEPTH SOIL CORES

NRCS Soil Characterization DatabaseNRCS Soil Characterization Database

• 605 pedons northeastern and north central USA605 pedons northeastern and north central USA

• Data required (bulk density, coarse fragments, C Data required (bulk density, coarse fragments, C fraction, horizon thickness)fraction, horizon thickness)

• 0-20 cm, 0-1 m, proportion of C to 1 m depth 0-20 cm, 0-1 m, proportion of C to 1 m depth occurring in surface 20 cmoccurring in surface 20 cm

• Extrapolated to 1 m only if reached C horizonExtrapolated to 1 m only if reached C horizon

BALTIMORE UFORE PLOTSBALTIMORE UFORE PLOTS

NRCS DATANRCS DATA

Birdsey (1992)Birdsey (1992)

n=19 n=5 n=7n=19

CUB HILL PLOTSCUB HILL PLOTS

Birdsey (1992)Birdsey (1992)

n=7 n=8 n=6

DENVER METROPOLITAN AREADENVER METROPOLITAN AREA

Schimel et al. (1985) Schimel et al. (1985)

Adapted from Galubiewski (2006)

NRCSNRCS

n=5n=2 n=3n=3n=19

COMPARISON OF RESIDENTIAL AREASCOMPARISON OF RESIDENTIAL AREAS

n=13n=26

COMPARISON OF NATIVE SOILSCOMPARISON OF NATIVE SOILS

??

n=7 n=19

   DenverDenver BaltimoreBaltimore

(kg m(kg m-2-2))

Pre-agriculturePre-agriculture 7.37.3 11.2 (6.7)11.2 (6.7)

AgricultureAgriculture ~2.5~2.5 5.45.4

Urban*Urban* 8.58.5 7.17.1

*includes impervious surfaces (3.3 kg m*includes impervious surfaces (3.3 kg m-2-2))

NET Change?NET Change?

+1.17+1.17 -4.1 (+2.6)-4.1 (+2.6)

CONCLUSIONSCONCLUSIONS

1.1. Residential soils differ less than native Residential soils differ less than native soils in SOC densitiessoils in SOC densities

2.2. Residential soils in Denver significantly Residential soils in Denver significantly higher than native short grass higher than native short grass (Baltimore less clear)(Baltimore less clear)

3.3. Net change Denver (increase SOC), Net change Denver (increase SOC), Baltimore (+ or – change?)Baltimore (+ or – change?)

4.4. Turf grass potential to sequester C in Turf grass potential to sequester C in soil (BUT, entire budget required)soil (BUT, entire budget required)

LIFE ZONELIFE ZONELIFE ZONE AREA C Density SoilAREA C Density SoilAREA C Density Soil C C C

(x10(x10(x10101010 mm22))mm22)) (kg m(kg m(kg m--222)) (x10(x10(x10141414g)g)g)

Northeast Forest*Northeast Forest*Northeast Forest* 20.8120.81 16.216.216.2 33.733.7

Northeast Cropland*Northeast Cropland*Northeast Cropland* -- 6.06.06.0 --

MidMidMid--Atlantic Forest*Atlantic Forest*Atlantic Forest* 20.2920.2920.29 11.211.211.2 22.722.7

MidMidMid--Atlantic Atlantic Atlantic Cropland*Cropland*Cropland* -- 4.24.24.2 --

Urban (residential)Urban (residential) 6.35 6.35 6.35 14.4 (14.4 ( ±±±1.2)1.2)1.2) 9.849.849.84

USA Urban (total) USA Urban (total) USA Urban (total) 30.0630.06**30.06** 23.1523.15

USA (total)USA (total)USA (total) 915.9915.9915.9 6.8 (?)6.8 (?)6.8 (?) 619.15619.15

***BirdseyBirdseyBirdsey (1992)(1992)(1992)

7.7 (7.7 (±0.2)±0.2)******

SoutheastSoutheast Forest*Forest* 34.2234.22 7.77.7 26.326.3

SoutheastSoutheast Cropland*Cropland* -- 2.62.6 --

**Nowak et al. (1996)**Nowak et al. (1996)***Pouyat et al. (2006)***Pouyat et al. (2006)