Topsoil Loss and Modification During Suburbanization: Impact on Demands for Municipal Water R.G. Darmody Department of Natural Resources and Environmental Sciences University of Illinois
The Problem Demands on water in the US, have grown tremendously. In 1900, the Americans used 5-10 gpd. In 2000, 50-100 gallons a day. 36% of U.S. domestic water goes to lawn and garden irrigation Sprawl, suburbanization National Wildlife Federation, 2004; Sustainable Building Sourcebook, 2004
Topsoil Definitions Topsoil is one of those things that are hard to define, but you know it when you see it. - Upper, outermost layer of soil, top 2 to 8 in., highest organic matter and microorganisms, most biological activity. - Upper surface of the Earth's crust, no deeper than 20 cm, rich humus, minerals, and compost, nutritious plant substrate. - Surface soil, including the organic layer in which plants root, farmers turn over in plowing. - Fertile, upper part of the soil. - Organically enriched A horizon at the soil surface. - Upper part of the solum, the plow-layer, synonymous with A horizon.
Illinois Topsoil, best in the world!
Research Methods 1. Site selection 2. Soil sample retrieval - description, lab materials; 3/site 3. Soil bulk density sampling; volumetric core sampler; 3/site 4. Infiltration measurement infiltrometer; 3/site 5. Penetrometer resistance; penetrometer 6. Soil fertility analysis, extractable elements
Research Sites Plainfield - 12 recently constructed schools, 1 8 years old - Sampled near and away from building, three reps per sub-site - Two reference farm fields, 10,000 years old - Total of 126 samples Champaign - 10 residential sites, 2 15 years old - Front and back lawns, three reps per site - 1 commercial site, 2 sun-sites - Three reference farm fields, 12,000 years old - Total of 69 samples/observation sets
Aux Sable Middle School Soil Map 2 1
Plainfield Reference Site
Commercial site
Plainfield Pre-Development Soils Site Soil Map Unit Soil Series Drainage Class Soil Classification 1 541B Graymont SiL Moderately Fine-silty, mixed, superactive, mesic Well Oxyaquic Argiudolls 2 541B Graymont SiL 3 541B Graymont SiL 4 356A Elpaso SiCL Poorly Fine-silty, mixed, superactive, mesic Typic Endoaquolls 5 293A Andres SiL Somewhat Fine-loamy, mixed, superactive, mesic Poorly Aquic Argiudolls 6 293A Andres SiL 7 541B Graymont SiL Mod. Well Fine-silty, mixed, superactive, mesic Oxyaquic Argiudolls 8 541B Graymont SiL 9 356A Elpaso SiCL Poorly Fine-silty, mixed, superactive, mesic Typic Endoaquolls 10 356A Elpaso SiCL 11 442A Mundelein SiL Somewhat Fine-silty, mixed, superactive, mesic Poorly Aquic Argiudolls 12 152A Drummer SiCL Poorly Fine-silty, mixed, superactive, mesic Typic Endoaquolls 13 293A Andres SiL Somewhat Fine-loamy, mixed, superactive, mesic Poorly Aquic Argiudolls 14 293A Andres SiL
Champaign Pre-Development Soils Site Soil Map Unit Soil Series 1 152A Drummer SiCL Drainage Class Poorly Soil Classification Fine-silty, mixed, superactive, mesic Typic Endoaquolls 2 152A Drummer SiCL 3 56B Dana SiL Moderately Fine-silty, mixed, superactive, mesic Well Oxyaquic Argiudolls 4 330A Peotone SiCL Very Poorly Fine, smectitic, mesic Cumulic Vertic Endoaquolls 5 152A Drummer SiCL Poorly Fine-silty, mixed, superactive, mesic Typic Endoaquolls 6 152A Drummer SiCL 7 152A Drummer SiCL 8 154B Flanagan SiL Somewhat Fine, smectitic, mesic Aquic Poorly Argiudolls 9 154B Flanagan SiL 10 152A Drummer SiCL Poorly Fine-silty, mixed, superactive, mesic Typic Endoaquolls 11 330A Peotone SiCL Very Poorly Fine, smectitic, mesic Cumulic Vertic Endoaquolls 12 152A Drummer SiCL Poorly Fine-silty, mixed, superactive, mesic Typic Endoaquolls 13 152A Drummer SiCL Poorly
Plainfield Pre-Development Soils Soil Map Unit Soil Map Unit Name Avail. H 2 O (in/in) Bulk Density Ksat (in/hr) ph CEC SOM % Limitation, lawns 152A Drummer SiCL 0.21-0.23 1.10-1.30 0.6-2.0 5.6-7.8 17-23 4.0-7.0 Very limited: depth to saturated zone, ponding 293A Andres SiL 0.17-0.21 1.35-1.55 0.6-2.0 5.6-7.3 10-22 3.5-5.0 Somewhat limited: depth to saturated zone 356A Elpaso SiCL 0.21-0.23 1.15-1.35 0.6-2.0 5.6-7.3 26-35 4.0-7.0 Very limited: depth to saturated zone, ponding 442A Mundelein SiL 0.22-0.24 1.15-1.30 0.6-2.0 5.6-7.3 18-26 3.0-5.0 Somewhat limited: depth to saturated zone 541B Graymont SiL 0.22-0.24 1.15-1.35 0.6-2.0 6.1-7.3 19-24 3.0-5.0 Not limited
Champaign Pre-Development Soils Soil Map Unit Soil Map Unit Name Avail. H 2 O (in/in) Bulk Density Ksat (in/hr) ph SOM % CEC Limitation, lawns 56B Dana SiL 0.22-0.24 1.25-1.50 0.6-2.0 5.6-7.3 3.0-5.0 17-26 Slight 152A Drummer SiCL 0.21-0.23 1.10-1.30 0.6-2.0 5.6-7.8 4.0-7.0 24-35 Severe, ponding 154B Flanagan SiL 0.22-0.24 1.20-1.40 0.6-2.0 5.1-7.3 4.0-5.0 20-26 Moderate, wetness 330A Peotone SiCL 0.21-0.23 1.20-1.40 0.6-2.0 5.6-7.8 5.0-7.0 30-38 Severe, ponding
Standard Infiltration Ratings Rate (in/hr) Rating < 0.2 very low 0.2 to 0.4 low 0.4 to 0.75 moderately low 0.75 to 1.25 moderate 1.25 to 1.75 moderately high 1.75 to 2.5 high > 2.5 very high
Penetrometer Resistance of Soil in Lawn Penetrometer Resistance (MPa) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 10 Depth (cm) 20 30 40 50 60 70 80
Soil Cores from Plainfield sites
Champaign Lawn Soil Cores
Soil Texture Plainfield Sites Champaign Sites 80 90 80 90 70 Clay 70 Clay 60 60 20 30 40 10 Loamy Sand Sand 50 Sandy Clay Sandy Clay Loam Sandy Loam Clay Loam Loam Silty Clay Silty Clay Loam Silt Loam Silt 20 30 40 10 Loamy Sand Sand 50 Sandy Clay Sandy Clay Loam Sandy Loam Clay Loam Loam Silty Clay Silty Clay Loam Silt Loam Silt Percent Sand Percent Sand Hydrometer method for silt and clay, sands by sieving.
Plainfield Extractable elements (0-8 cm) Site CEC meq/ 100g ph Org. Matter % Extractable (mg kg -1 ) S P Ca Mg K Na B Fe Mn Cu Zn Al Aux Sable 26 ab 6.7 ab 3.7 b 48 a 56 ab 3660 824 c 171 e 27 0.7 b 160 c 96 a 4.0 ab 2.3 b 788 b Plain. South 27 ab 6.9 ab 4.9 ab 57 a 65 ab 3878 835 c 277 c 24 0.8 ab 125 d 97 a 9.5 a 3.2 b 616 d Eagle Point 27 ab 7.0 ab 4.4 ab 33 ab 52 b 3744 950 ab 247 cd 20 0.7 ab 171 bc 98 a 3.6 ab 2.1 b 699 c Ridge 29 ab 7.2 a 5.4 a 34 ab 118 a 3801 1033 a 377 a 24 0.9 a 156 cd 72 b 6.1 a 11.7 a 599 d Dra. Point 29 a 7.3 a 5.2 ab 32 ab 180 a 4111 920 bc 325 b 26 0.9 a 147 cd 81 ab 7.0 a 17.0 a 586 d Ch. Reed 28 ab 6.6 b 4.3 ab 28 b 54 b 3922 962 c 274 c 25 0.8 ab 137 cd 56 c 4.1 ab 2.3 b 737 bc Ref. 24 b 5.8 c 5.0 ab 38 ab 98 ab 3192 828 c 220 d 27 0.7 b 224 a 38 d 3.3 b 3.8 b 835 a Mehlich III extractables, water ph.
Champaign Extractable elements (0-8 cm) Lawn Type CEC (meq/ 100g) ph Org. Matter (%) Extractable (mg kg -1 ) S P Ca Mg K Na B Fe Mn Cu Zn Al R 20 7.5 2.8 10 17 2849 658 126 40 0.7 379 101 4.6 1.5 677 R 21 7.5 2.8 14 39 3013 626 195 55 0.8 275 91 2.8 2.1 567 R 21 8.0 1.8 27 15 3284 462 121 70 0.7 235 127 2.3 1.8 420 R 21 7.8 2.0 31 19 3076 652 142 69 0.7 326 152 3.5 1.9 654 R 21 7.9 2.7 10 7 2801 746 110 45 0.8 169 222 2.7 1.3 765 R 16 7.6 3.2 11 10 2356 490 102 38 0.8 194 73 1.8 1.1 737 R 22 8.0 2.1 13 16 3162 672 116 46 0.7 367 102 2.6 1.2 616 C 24 8.1 2.1 60 13 3536 667 125 91 1.0 370 201 4.2 3.7 575 C 20 8.0 3.6 24 42 2822 595 213 52 0.8 421 101 3.3 4.8 684 R 21 7.8 2.9 10 7 2807 769 104 55 0.8 168 222 2.9 1.5 770 Mehlich III extractables, water ph.
Bulk Density Sampler
1.6 Plainfield Soil Bulk Densities 1.4 Bulk Density (g/cc) 1.2 1.0 0.8 0.6 0.4 0.2 0.0
40 Plainfield Soil Volumetric Water Contents 35 Volumetric H 2 O (%) 30 25 20 15 10 5 0
Infiltrometer
4.5 Comparison of Infiltration Means 4.0 Alternative Mean (in/hr) 3.5 3.0 2.5 2.0 1.5 Site Geomean Site Harmean Site Trimean Site Median 1.0 0.5 0.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 Arithmetic Mean (in/hr)
Plainfield Sites Bulk Density vs. Infiltration Rate 1.6 Bulk Density (g/cc) 1.5 1.4 1.3 1.2 1.1 1.0 0 2 4 6 8 10 12 Infiltration Rate (in/hr)
Champaign Sites 1.8 Bulk Density vs. Infiltration Rate 1.7 Bulk Density (g/cc) 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0 5 10 15 20 25 Infiltration Rate (in/hr)
Take Home Message 1. Illinois has some of the best soils in the world for agriculture 2. Illinois is a rapidly suburbanizing state 3. Water resources are limited, particularly in the collar counties 4. Soils are impacted by development, pavement is forever 5. Water that does not infiltrate is not available to plants and runs off exacerbating flooding 6. Soil bulk density and Infiltration rates are highly variable on disturbed soils 7. Statistically the research did not support the hypothesis that infiltration is negatively impacted by development.
Soil at Eagle Point School
Soil Cores from Champaign sites 60