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Using biodiversity to link agricultural productivity with environmental quality: Results from three field experiments in Iowa

Published online by Cambridge University Press:  11 March 2013

Matt Liebman ,
Matthew J. Helmers ,
Lisa A. Schulte  and
Craig A. Chase
Matt Liebman*
Affiliation:
Department of Agronomy, Iowa State University, Ames, IA 50011-1010, USA.
Matthew J. Helmers
Affiliation:
Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011-3080, USA.
Lisa A. Schulte
Affiliation:
Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA 50011-3221, USA.
Craig A. Chase
Affiliation:
Leopold Center for Sustainable Agriculture, Iowa State University, Ames, IA 50010-1050, USA.
*
*Corresponding author: mliebman@iastate.edu
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Abstract

Agriculture in the US Corn Belt is under increasing pressure to produce greater quantities of food, feed and fuel, while better protecting environmental quality. Key environmental problems in this region include water contamination by nutrients and herbicides emitted from cropland, a lack of non-agricultural habitat to support diverse communities of native plants and animals, and a high level of dependence on petrochemical energy in the dominant cropping systems. In addition, projected changes in climate for this region, which include increases in the proportion of precipitation coming from extreme events could make soil and water conservation in existing cropping systems more difficult. To address these challenges we have conducted three cropping systems projects in central Iowa: the Marsden Farm Cropping Systems experiment, the Science-based Trials of Row-crops Integrated with Prairies (STRIPs) experiment, and the Comparison of Biofuel Systems (COBS) experiment. Results from these experiments indicate that (1) diversification of the dominant corn–soybean rotation with small grains and forage legumes can permit substantial reductions in agrichemical and fossil hydrocarbon use without compromising yields or profitability; (2) conversion of small amounts of cropland to prairie buffer strips can provide disproportionately large improvements in soil and water conservation, nutrient retention, and densities of native plants and birds; and (3) native perennial species can generate large amounts of biofuel feedstocks and offer environmental benefits relative to corn- and soybean-based systems, including greater carbon inputs to soil and large reductions in nitrogen emissions to drainage water. Increasing biodiversity through the strategic integration of perennial plant species can be a viable strategy for reducing reliance on purchased inputs and for increasing agroecosystem health and resilience in the US Corn Belt.

Keywords

biodiversitymultifunctionalityconservationcropping systems
Type
Research Papers
Information
Renewable Agriculture and Food Systems , Volume 28 , Issue 2 , June 2013 , pp. 115 - 128
Copyright
Copyright © Cambridge University Press 2013

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References

1National Agricultural Statistics Service (NASS). 2011. 2010 State Agriculture Overview–Iowa. NASS, U.S. Department of Agriculture, Washington, DC. Available at Web site http://www.nass.usda.gov/Statistics_by_State/Ag_Overview/AgOverview_IA.pdf (verified November 15, 2011).Google Scholar
2Nebraska Energy Office. 2011. Ethanol Facilities Capacity by State. Nebraska Energy Office, Lincoln, NE. Available at Web site http://www.neo.ne.gov/statshtml/121.htm (verified November 15, 2011).Google Scholar
3Gilliom, R.J., Barbash, J.E., Crawford, C.G., Hamilton, P.A., Martin, J.D., Nakagaki, N., Nowell, L.H., Scott, J.C., Stackelberg, P.E., Thelin, G.P., and Wolock, D.M. 2006. The Quality of our Nation's Waters: Pesticides in the Nation's Streams and Ground Water, 1992–2001. Circular 1291. U.S. Geological Survey, Reston, VA.Google Scholar
4Alexander, R.B., Smith, R.A., Schwarz, G.E., Boyer, E.W., Nolan, J.V., and Brakebill, J.W. 2008. Differences in phosphorus and nitrogen delivery to the Gulf of Mexico from the Mississippi River Basin. Environmental Science and Technology 42:822–830.Google Scholar
5Iowa Department of Natural Resources (Iowa DNR). 2010. The Final 2008 Iowa List of Section 303(d) Impaired Waters. Iowa DNR, Des Moines, IA. Available at Web site http://www.igsb.uiowa.edu/wqm/ImpairedWaters/Year2008/FactSheetForFinal-Approved2008List.pdf. (verified November 15, 2011).Google Scholar
6Hoekstra, J.M., Boucher, T.M., Ricketts, T.H., and Roberts, C. 2005. Confronting a biome crisis: Global disparities of habitat loss and protection. Ecology Letters 8:23–29.Google Scholar
7Klopatek, J.M., Olson, R.J., Emerson, C.J., and Jones, J.L. 1979. Land-use conflicts with natural vegetation in the United States. Environmental Conservation 6:191–199.CrossRefGoogle Scholar
8Samson, F. and Knopf, F. 1994. Prairie conservation in North America. BioScience 44:418–421.Google Scholar
9Schilling, K.E. and Spooner, J. 2006. Effects of watershed-scale land use change on stream nitrate concentrations. Journal of Environmental Quality 27:2132–2145.Google Scholar
10Iowa Department of Natural Resources (Iowa DNR). 2007. Iowa Wildlife Action Plan. IDNR, Des Moines, IA. Available at Web site http://www.iowadnr.gov/Environment/WildlifeStewardship/IowaWildlifeActionPlan.aspx (verified November 15, 2011).Google Scholar
11National Agricultural Statistics Service (NASS). 2011. Crop Summary: Acres Planted, Harvested, Yield and Production, Iowa and U.S. NASS, U.S. Department of Agriculture, Washington, DC. Available at Web site http://www.nass.usda.gov/Statistics_by_State/Iowa/Publications/Annual_Statistical_Bulletin/2009/47_09.pdf (verified November 15, 2011).Google Scholar
12Hatfield, J.L., McMullen, L.D., and Jones, C.S. 2009. Nitrate–nitrogen patterns in the Raccoon River Basin related to agricultural practices. Journal of Soil and Water Conservation 64:190–199.Google Scholar
13Sulc, R.M. and Tracy, B.F. 2007. Integrated crop–livestock systems in the U.S. Corn Belt. Agronomy Journal 99:335–345.CrossRefGoogle Scholar
14Brown, P.W. and Schulte, L.A. 2011. Agricultural landscape change (1937–2002) in three townships in Iowa, USA. Landscape and Urban Planning 100:202–212.Google Scholar
15Kort, J. 1988. Benefits of windbreaks to field and forage crops. Agriculture, Ecosystems, and Environment 22/23:165–190.Google Scholar
16Cruse, R.M. and Dinnes, D.L. 1995. Spatial and temporal diversity in production fields. In Olson, R., Francis, C., and Kaffka, S. (eds). Exploring the Role of Diversity in Sustainable Agriculture. American Society of Agronomy–Crop Science Society of America–Soil Science Society of America, Madison, WI, p. 73–94.Google Scholar
17Gardiner, M.M., Landis, D.A., Gratton, C., DiFonzo, C.D., O'Neal, M., Chacon, J., Wayo, M., Schmidt, N., Mueller, E., and Heimpel, G.E. 2009. Landscape diversity enhances biological control of an introduced crop pest in the north-central U.S. Ecological Applications 19:143–154.Google Scholar
18Schulte, L.A., Liebman, M., Asbjornsen, H., and Crow, T.R. 2006. Agroecosystem restoration through strategic integration of perennials. Journal of Soil and Water Conservation 61:164–169.Google Scholar
19Asbjornsen, H., Hernandez-Santana, V., Liebman, M., Bayala, J., Chen, J., Helmers, M., Ong, C.K., and Schulte, L. In review. Targeting perennial vegetation in agricultural landscapes for enhancing ecosystem services. Agriculture, Ecosystems and Environment.Google Scholar
20Economic Research Service (ERS). 2011. Fertilizer Use and Price. ERS-U.S. Department of Agriculture, Washington, DC. Available at Web site http://www.ers.usda.gov/Data/FertilizerUse/ (verified November 15, 2011).Google Scholar
21National Agricultural Statistics Service (NASS). 2011. Agricultural Chemical use Database. NASS, U.S. Department of Agriculture, Washington, DC. Available at Web site http://www.pestmanagement.info/nass/app_statcs3_crop.cfm (verified November 15, 2011).Google Scholar
22Schilling, K.E. and Libra, R.D. 2000. The relationship of nitrate concentrations in streams to row crop land use in Iowa. Journal of Environmental Quality 29:1846–1851.Google Scholar
23Jaynes, D.B., Colvin, T.S., Karlen, D.L., Cambardella, C.A., and Meek, D.W. 2001. Nitrate loss in subsurface drainage as affected by nitrogen fertilizer rate. Journal of Environmental Quality 30:1305–1314.Google Scholar
24Broussard, W. and Turner, R.E. 2009. A century of changing land-use and water-quality relationships in the continental U.S. Frontiers in Ecology and the Environment 7:302–307.Google Scholar
25Sullivan, D.J., Vecchia, A.V., Lorenz, D.L., Gilliom, R.J., and Martin, J.D. 2009. Trends in pesticide concentrations in Corn Belt streams, 1996–2006. Scientific Investigations Report 2009–5132. National Water Quality Assessment Program, U.S. Geological Survey, Reston, VA.Google Scholar
26Burkart, M.R. and James, D.E. 1999. Agricultural-nitrogen contributions to hypoxia in the Gulf of Mexico. Journal of Environmental Quality 2:850–859.Google Scholar
27Randall, G.W., Huggins, D.R., Russelle, M.P., Fuchs, D.J., Nelson, W.W. and Anderson, J.L. 1997. Nitrate losses through subsurface tile drainage in Conservation Reserve Program, alfalfa, and row crop systems. Journal of Environmental Quality 26:1240–1247.Google Scholar
28Fuhrer, G.J., Gilliom, R.J., Hamilton, P.A., Morace, J.L., Nowell, L.H., Rinella, J.F., Stoner, J.D., and Wentz, D.A. 1999. The Quality of our Nation's Waters: Nutrient and Pesticides. Circular 1225. U.S. Geological Survey, Reston, VA.Google Scholar
29Hayes, T.B., Collins, A., Lee, M., Mendoza, M., Noriega, N., Stuart, A.A., and Vonk, A. 2002. Hermaphroditic, demasculinized frogs after exposure to the herbicide atrazine at low, ecologically relevant doses. Proceedings of the National Academy of Sciences USA 99:5476–5480.Google Scholar
30Relyea, R.A. 2005. The impact of insecticides and herbicides on the biodiversity and productivity of aquatic communities. Ecological Applications 15:618–627.Google Scholar
31Magdoff, F., Lanyon, L., and Liebhardt, W. 1997. Nutrient cycling, transformations, and flows: Implications for a more sustainable agriculture. Advances in Agronomy 60:1–73.Google Scholar
32Dinnes, D.L., Karlen, D.L., Jaynes, D.B., Kaspar, T.C., Hatfield, J.L., Colvin, T.S. and Cambardella, C.A. 2002. Nitrogen management strategies to reduce nitrate leaching in tile-drained Midwestern soils. Agronomy Journal 94:153–171.Google Scholar
33Liebman, M. and Gallandt, E.R. 1997. Many little hammers: Ecological management of crop-weed interactions. In Jackson, L.E. (ed.). Ecology in Agriculture. Academic Press, Orlando, FL, p. 287–339.Google Scholar
34Liebman, M. and Davis, A.S. 2009. Managing weeds in organic farming systems: An ecological approach. In Francis, C.A. (ed.). Organic Farming: The Ecological System. American Society of Agronomy, Madison, WI, p. 173–196.Google Scholar
35Blackmer, A.M., Voss, R.D., and Mallorino, A.P. 1997. Nitrogen Fertilizer Recommendations for Corn in Iowa. Publication PM-1714. Iowa State University Extension, Ames, IA. Available at Web site http://www.extension.iastate.edu/Publications/PM1714.pdf (verified November 15, 2011).Google Scholar
36Liebman, M., Gibson, L.R., Sundberg, D.N., Heggenstaller, A.H., Westerman, P.R., Chase, C.A., Hartzler, R.G., Menalled, F.D., Davis, A.S., and Dixon, P.M. 2008. Agronomic and economic performance characteristics of conventional and low-external-input cropping systems in the central Corn Belt. Agronomy Journal 100:600–610.CrossRefGoogle Scholar
37Cruse, M.J., Liebman, M., Raman, D.R., and Wiedenhoeft, M. 2010. Fossil energy use in conventional and low-external-input cropping systems. Agronomy Journal 102:934–941.CrossRefGoogle Scholar
38Gómez, R., Liebman, M., Sundberg, D.N., and Chase, C.A. 2012. Comparison of crop management strategies involving crop genotype and weed management practices in conventional and low-external-input cropping systems. Renewable Agriculture and Food Systems, in press. doi:10.1017/S1742170512000142.Google Scholar
39Fox, R.H. and Piekielek, W.P. 1988. Fertilizer N equivalence of alfalfa, birdsfoot trefoil, and red clover for succeeding corn crops. Journal of Production Agriculture 1:313–317.Google Scholar
40Morris, T.F., Blackmer, A.M., and El-Hout, N.M. 1993. Optimal rates of nitrogen fertilization for first-year corn after alfalfa. Journal of Production Agriculture 6:344–350.Google Scholar
41Drinkwater, L.E., Wagoner, P., and Sarrantonio, M. 1998. Legume-based cropping systems have reduced carbon and nitrogen losses. Nature 396:262–265.Google Scholar
42Porter, P.M., Lauer, J.G., Lueschen, W.E., Ford, J.H., Hoverstad, T.R., Oplinger, E.S., and Crookston, R.K. 1997. Environment affects the corn and soybean rotation effect. Agronomy Journal 89:441–448.Google Scholar
43Coulter, J.A., Sheaffer, C.C., Wyse, D.L., Haar, M.J., Porter, P.M., Quiring, S.R., and Klossner, L.D. 2011. Agronomic performance of cropping systems with contrasting crop rotations and external inputs. Agronomy Journal 103:182–192.Google Scholar
44Magdoff, F.R. and Amadon, J.F. 1980. Yield trends and soil chemical change resulting from nitrogen and manure application to continuous corn. Agronomy Journal 72:161–164.Google Scholar
45Eghball, B. and Power, J.F. 1999. Composted and non-composted manure application to conventional and no-tillage systems: Corn yield and nitrogen uptake. Agronomy Journal 91:819–825.Google Scholar
46McAndrews, G.A., Liebman, M., Cambardella, C.A., and Richard, T.L. 2006. Residual effects of composted and fresh solid swine (Sus scrofa L.) manure on soybean [Glycine max (L.) Merr.] growth and yield. Agronomy Journal 98:873–882.Google Scholar
47Heggenstaller, A.H., Menalled, F.D., Liebman, M., and Westerman, P.R. 2006. Seasonal patterns in post-dispersal seed predation of Abutilon theophrasti and Setaria faberi in three cropping systems. Journal of Applied Ecology 43:999–1010.Google Scholar
48O'Rourke, M.E., Heggenstaller, A., Liebman, M., and Rice, M.E. 2006. Post-dispersal weed seed predation by invertebrates in conventional and low-external-input crop rotation systems. Agriculture, Ecosystems and Environment 116:280–288.Google Scholar
49Williams, C.L., Liebman, M., Westerman, P.R., Borza, J., Sundberg, D., and Danielson, B. 2009. Over-winter predation of Abutilon theophrasti and Setaria faberi seeds in arable land. Weed Research 49:439–447.Google Scholar
50Westerman, P.R., Liebman, M., Menalled, F.D., Heggenstaller, A.H., Hartzler, R.G., and Dixon, P.M. 2005. Are many little hammers effective? Velvetleaf population dynamics in two- and four-year crop rotation systems. Weed Science 53:382–392.CrossRefGoogle Scholar
51Knox, J.C. 2006. Floodplain sedimentation in the Upper Mississippi Valley: Natural versus human accelerated. Geomorphology 79(3–4):286–310.Google Scholar
52Cox, C., Hug, A., and Bruzelius, N. 2011. Losing Ground. Environmental Working Group, Washington, DC. Available at Web site http://www.ewg.org/losingground/ (verified November 15, 2011).Google Scholar
53Dosskey, M.G., Helmers, M.J., Eisenhauer, D.E., Franti, T.G., and Hoagland, K.D. 2002. Assessment of concentrated flow through riparian buffers. Journal of Soil and Water Conservation 57:336–343.Google Scholar
54Robinson, C.A., Ghaffarzadeh, M., and Cruse, R.M. 1996. Vegetative filter strip effects on sediment concentration in cropland runoff. Journal of Soil and Water Conservation 51:227–230.Google Scholar
55Camill, P., McKone, M.J., Sturges, S.T., Severud, W.J., Ellis, E., Limmer, J., Martin, C.B., Navratil, R.T., Purdie, A.J., Sandel, B.S., Talukder, S., and Trout, A. 2004. Community and ecosystem-level changes in a species-rich tall grass prairie restoration. Ecological Applications 14:1680–1694.Google Scholar
56Lee, K.H., Isenhart, T.M., Schultz, R.C., and Mickelson, S.K. 1999. Nutrient and sediment removal by switchgrass and cool-season grass filter strips in Central Iowa, USA. Agroforestry Systems 44:121–132.Google Scholar
57Dabney, S.M. 2003. Erosion control, vegetative. In Lal, R. (ed.). Encyclopedia of Soil Science. Marcel Dekker, New York, NY, p. 209–213.Google Scholar
58Le Couer, D., Baudry, J., Burel, F., and Thenail, C. 2002. Why and how we should study field boundary biodiversity in an agrarian landscape context. Agriculture, Ecosystems, and Environment 89:23–40.Google Scholar
59Ma, M., Tarmi, S., and Helenius, J. 2002. Revisiting the species-area relationship in a semi-natural habitat: Floral richness in agricultural buffer zones in Finland. Agriculture, Ecosystems, and Environment 89:137–148.Google Scholar
60Marshall, E.J.P. and Moonen, A.C. 2002. Field margins in northern Europe: Their functions and interactions with agriculture. Agriculture, Ecosystems, and Environment 89:5–21.Google Scholar
61Van Buskirk, J. and Willi, Y. 2004. Enhancement of biodiversity within set-aside land. Conservation Biology 18:987–994.Google Scholar
62Berges, S.A., Schulte, L.A., Isenhart, T.M., and Schultz, R.C. 2010. Bird species diversity in riparian buffers, row crop fields, and grazed pastures within agriculturally dominated watersheds. Agroforestry Systems 79:97–110.Google Scholar
63Walk, J.W., Kershner, E.L., Benson, T.J., and Warner, R.E. 2010. Nesting success of grassland birds in small patches in an agricultural landscape. The Auk 127:328–334.Google Scholar
64Bryan, G.G. and Best, L.B. 1991. Bird abundance and species richness in grassed waterways in Iowa rowcrop fields. American Midland Naturalist 126:90–102.Google Scholar
65Best, L.B., Freemark, K.E., Dinsmore, J.J., and Camp, M. 1995. A review and synthesis of habitat use by breeding birds in agricultural landscapes of Iowa. American Midland Naturalist 134:1–29.Google Scholar
66Conover, R.R., Burger, L.W. Jr, and Linder, E.T. 2009. Breeding bird response to field border presence and width. The Wilson Journal of Ornithology 121:548–555.Google Scholar
67Burger, W.L. Jr, Barbour, P.J., and Smith, M.D. 2010. Grassland Bird Population Responses to Upland Habitat Buffer Establishment. Wildlife Insight. U.S. Department of Agriculture, Natural Resources Conservation Service, Washington, DC.Google Scholar
68Henningsen, J.C. and Best, L.B. 2005. Grassland bird use of riparian filter strips in southeast Iowa. Journal of Wildlife Management 69:198–210.Google Scholar
69Arnold, T.W. and Higgins, K.F. 1986. Effects of shrub coverage on birds on North Dakota mixed-grass prairies. Canadian Field-Naturalist 100:10–14.Google Scholar
70Hughes, J.P., Robel, R.J., Kemp, K.E., and Zimmerman, J.L. 1999. Effects of habitat on Dickcissel abundance and nest success in Conservation Reserve Program fields in Kansas. Journal of Wildlife Management 63:523–529.Google Scholar
71Ralph, C.J., Geupel, G.R., Pyle, P., Martin, T.E., and DeSante, D.F. 1993. Handbook of field methods for monitoring landbirds. General Technical Report PSW-GTR-144. USDA Forest Service Pacific Southwest Research Station, Albany, CA.Google Scholar
72Hernández-Santana, V., Zhou, X., Helmers, M.J., Asbjornsen, H., Kolka, R., and Tomer, M. In review. Native prairie filter strips reduce runoff from hillslopes under annual row-crop systems in Iowa, USA. Journal of Hydrology.Google Scholar
73Helmers, M.J., Zhou, X., Asbjornsen, H., Kolka, R., Tomer, M.D., and Cruse, R. 2012. Sediment removal by perennial filter strips in row-cropped ephemeral watersheds. Journal of Environmental Quality 41(5):1531–1539.Google Scholar
74Jones, S.L. and Cornely, J.E. 2002. Vesper sparrow (Pooecetes gramineus). In Poole, A. (ed.). The Birds of North America Online. Cornell Lab of Ornithology, Ithaca, New York. Available at Web site http://bna.birds.cornell.edu/bna/species/624 (verified November 15, 2011).Google Scholar
75Temple, S.A. 2002. Dickcissel (Spiza americana). In: Poole, A. (ed.). The Birds of North America Online. Cornell Lab of Ornithology, Ithaca, New York. Available at Web site http://bna.birds.cornell.edu/bna/species/703 (verified November 15, 2011).Google Scholar
76U.S. Climate Change Science Program/U.S. Global Change Research Program (USCCP/USGCRP). 2000. Climate Change Impacts on the United States–The Potential Consequences of Climate Variability and Change Overview: Midwest. USCCP/USGCRP, Washington, DC. Available at Web site http://www.usgcrp.gov/usgcrp/Library/nationalassessment/overviewmidwest.htm (verified November 15, 2011).Google Scholar
77Rosenzweig, C., Tubiello, F.N., Goldberg, R., Mills, E., and Bloomfield, J. 2002. Increased crop damage in the U.S. from excess precipitation under climate change. Global Environmental Change 12:197–202.Google Scholar
78Angel, J.R., Palecki, M.A., and Hollinger, S.E. 2005. Storm precipitation in the United States. Part II: Soil erosion characteristics. Journal of Applied Meteorology 44:947–959.Google Scholar
79Secchi, S., Tyndall, J., Schulte, L.A., and Asbjornsen, H. 2008. Raising the stakes: High crop prices and conservation. Journal of Soil and Water Conservation 63:68A–73A.CrossRefGoogle Scholar
80Wiens, J., Fargione, J., and Hill, J. 2011. Biofuels and biodiversity. Ecological Applications 21:1085–1095.Google Scholar
81Hatfield, J.L., Boote, K.J., Kimball, B.A., Ziska, L.H., Izaurralde, R.C., Ort, D.R., Thomson, A.M., and Wolfe, D. 2011. Climate impacts on agriculture: Implications for crop production. Agronomy Journal 103:351–370.Google Scholar
82Economic Research Service (ERS). 2011. Bioenergy: ERS Research Findings on the Economics of Biofuels. ERS-U.S. Department of Agriculture, Washington, DC. Available at Web site http://www.ers.usda.gov/Briefing/Bioenergy/ResearchFindings.html (verified November 15, 2011).Google Scholar
83Renewable Fuels Association (RFA). 2011. Ethanol Facts. RFA, Washington, DC. Available at Web site http://www.ethanolrfa.org/pages/ethanol-facts (verified November 15, 2011).Google Scholar
84Donner, S.D. and Kucharik, C.J. 2008. Corn-based ethanol production compromises goal of reducing nitrogen export by the Mississippi River. Proceedings of the National Academy of Sciences USA 105:4513–4518.Google Scholar
85Secchi, S., Gassman, P.W., Jha, M., Kurkalova, L., and Kling, C.L. 2011a. Potential water quality changes due to corn expansion in the Upper Mississippi River Basin. Ecological Applications 21:1068–1084.Google Scholar
86Secchi, S., Kurkalova, L., Gassman, P.W., and Hart, C. 2011. Land use change in a biofuel hotspot: The case of Iowa, USA. Biomass and Bioenergy 35:2391–2400.Google Scholar
87Fargione, J., Hill, J., Tilman, D., Polasky, D., and Hawthorne, P. 2008. Land clearing and the biofuel carbon debt. Science 319:1235–1238.Google Scholar
88Searchinger, T., Heimlich, R., Houghton, R.A., Dong, F.X., Elobeid, A., Fabiosa, J., Tokgoz, S., Hayes, D., and Yu, T.H. 2008. Use of U.S. croplands for biofuels increases greenhouse gases through emissions from land use change. Science 319:1238–1240.Google Scholar
89Fargione, J.E., Cooper, T.R., Flaspohler, D.J., Hill, J., Lehman, C., McCoy, T., McLeod, S., Nelson, E.J., Oberhauser, K.S., and Tilman, D. 2009. Bioenergy and wildlife: Threats and opportunities for grassland conservation. BioScience 59:767–777.Google Scholar
90Meehan, T.D., Hurlbert, A.H., and Gratton, C. 2010. Bird communities in future bioenergy landscapes of the Upper Midwest. Proceedings of the National Academy of Sciences USA 107:18533–18538.Google Scholar
91Landis, D.A., Gardiner, M.M., van der Werf, W., and Swinton, S.M. 2008. Increasing corn for biofuel production reduces biocontrol services in agricultural landscapes. Proceedings of the National Academy of Sciences USA 105:20552–20557.Google Scholar
92Tilman, D., Hill, J., and Lehman, C. 2006. Carbon-negative biofuels from low-input high-diversity grassland biomass. Science 314:1598–1600.Google Scholar
93Heaton, E.A., Dohleman, F.G., and Long, S.P. 2008. Meeting US biofuel goals with less land: The potential of Miscanthus. Global Change Biology 14:2000–2014.Google Scholar
94U.S. Department of Energy (USDOE). 2011. U.S. billion-ton update: Biomass supply for a bioenergy and bioproducts industry. R.D. Perlack and B.J. Stokes (leads). ORNL/TM-2011/224. Oak Ridge National Laboratory, Oak Ridge, TN. Available at Web site http://www1.eere.energy.gov/biomass/pdfs/billion_ton_update.pdf (verified November 15, 2011).Google Scholar
95Jordan, N., Boody, G., Broussard, W., Glover, J.D., Keeney, D., McCown, B.H., McIsaac, G., Muller, M., Murray, H., Neal, J., Pansing, C., Turner, R.E., Warner, K., and Wyse, D. 2007. Sustainable development of the bioeconomy. Science 316:1570–1571.Google Scholar
96Robertson, G.P., Hamilton, S.K., Del Grosso, S.J., and Parton, W.J. 2011. The biogeochemistry of bioenergy landscapes: Carbon, nitrogen, and water considerations. Ecological Applications 21:1055–1067.Google Scholar
97McIsaac, G.F., David, M.B., and Mitchell, C.A. 2010. Miscanthus and switchgrass production in central Illinois: Impacts on hydrology and inorganic nitrogen leaching. Journal of Environmental Quality 39:1790–1799.Google Scholar
98Blanco-Canqui, H. 2010. Energy crops and their implications on soil and environment. Agronomy Journal 102:403–419.Google Scholar
99Tufekcioglu, A., Raich, J.W., Isenhart, T.M., and Schultz, R.C. 2003. Biomass, carbon, and nitrogen dynamics of multispecies riparian buffers within an agricultural watershed in Iowa, USA. Agroforestry Systems 57:187–198.Google Scholar
100Adler, P.R., Sanderson, M.A., Weimer, P.J., and Vogel, K.P. 2009. Plant species composition and biofuel yields of conservation grasslands. Ecological Applications 19:2202–2209.Google Scholar
101Davis, S.C., Parton, W.J., Dohleman, F.G., Smith, C.M., Del Grosso, S., Kent, A.D., and DeLucia, E.H. 2010. Comparative biogeochemical cycles of bioenergy crops reveal nitrogen-fixation and low greenhouse gas emissions in a Miscanthus×giganteus agro-ecosystem. Ecosystems 13:144–156.Google Scholar
102Fletcher, R.J. Jr, Robertson, B.A., Evans, J., Doran, P.J., Alavalapati, J.R.R., and Schemske, D.W. 2011. Biodiversity conservation in the era of biofuels: Risks and opportunities. Frontiers in Ecology and the Environment 9:161–168.Google Scholar
103Santelmann, M.V., White, D., Freemark, K., Nassauer, J.L., Eilers, J.M., Vache, K.B., Danielson, B.J., Corry, R.C., Clark, M.E., Polasky, S., Cruse, R.M., Sifneos, J., Rustigian, H., Coiner, C., Wu, J., and Debinski, D. 2004. Assessing alternative futures for agriculture in Iowa, USA. Landscape Ecology 19:357–374.Google Scholar
104Boody, G., Vondracek, B., Andow, D.A., Krinke, M., Westra, J., Zimmerman, J., and Welle, P. 2005. Multifunctional agriculture in the United States. BioScience 55:27–38.CrossRefGoogle Scholar
105Shapouri, H. and Gallagher, P. 2005. USDA's 2002 ethanol cost-of production survey. Agricultural Economic Report 841. U.S. Department of Agriculture, Washington, DC. Available at Web site http://www.usda.gov/oce/reports/energy/USDA_2002_ETHANOL.pdf (verified November 15, 2011).Google Scholar
106Conley, S.P. and Tao, B. 2006. What is Biodiesel? ID-337. Purdue University Extension, West Lafayette, IN. Available at Web site http://www.ces.purdue.edu/extmedia/ID/ID-337.pdf (verified November 15, 2011).Google Scholar
107Hill, J., Nelson, E., Tilman, D., Polasky, S., and Tiffany, D. 2006. Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels. Proceedings of the National Academy of Sciences USA 103:11206–11210.Google Scholar
108Tilman, D., Wedin, D., and Knops, J. 1996. Productivity and sustainability influenced by biodiversity in grassland ecosystems. Nature 379:718–720.Google Scholar
109Tilman, D., Reich, P.B., Knops, J., Wedin, D., Mielke, T., and Lehman, C. 2001. Diversity and productivity in a long-term grassland experiment. Science 294:843–845.Google Scholar
110Jarchow, M.E. and Liebman, M. 2012. Tradeoffs in biomass and nutrient allocation in prairies and corn managed for bioenergy production. Crop Science 52:1330–1342.Google Scholar
111Robertson, G.P. and Swinton, S.M. 2005. Reconciling agricultural productivity and environmental integrity: A grand challenge for agriculture. Frontiers in Ecology and the Environment 3:38–46.Google Scholar
112Olson, R. 1995. Diversity in agricultural landscapes. In Olson, R., Francis, C., and Kaffka, S. (eds), Exploring the Role of Diversity in Sustainable Agriculture. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Madison, WI, p. 121–160.Google Scholar
113Larsen, G.L.D. 2011. Farming for ecosystem services: A case study of multifunctional agriculture in Iowa, USA. M.S. thesis, Iowa State University, Ames, IA.Google Scholar
114Naylor, R., Steinfeld, H., Falcon, W., Galloway, J., Smil, V., Bradford, E., Alder, J., and Mooney, H. 2005. Losing the links between livestock and land. Science 310:1621–1622.Google Scholar
115Burkart, M., James, D., Liebman, M., and Herndl, C. 2005. Impacts of integrated crop–livestock systems on nitrogen dynamics and soil erosion in western Iowa watersheds. Journal of Geophysical Research-Biogeosciences 110:G01009, doi:10.1029/2004JG000008 (on line).Google Scholar
116Russelle, M.P., Entz, M.H., and Franzluebbers, A.J. 2007. Reconsidering integrated crop–livestock systems in North America. Agronomy Journal 99:325–334.Google Scholar
117Mutel, C.F. (ed.). 2010. A Watershed Year: Anatomy of the Iowa Floods of 2008. University of Iowa Press, Iowa City, IA.Google Scholar
118Perkins, J. 2008. Soil, Water Conservation Took a Beating in Floods. Des Moines Register, July 30, 2008.Google Scholar
119Tilman, D., Socolow, R., Foley, J.A., Hill, J., Larson, E., Lynd, L., Pacala, S., Reilly, J., Searchinger, T., Somerville, C., and Williams, R. 2009. Beneficial biofuels—the food, energy, and environment trilemma. Science 325:270–271.Google Scholar
120Power, A.G. 2010. Ecosystem services and agriculture: Tradeoffs and synergies. Philosophical Transactions of the Royal Society B-Biological Sciences 365(1554):2959–2971.Google Scholar
121Environmental Working Group (EWG). 2011. Farm Subsidy Database. EWG, Washington, DC. Available at Web site http://farm.ewg.org/region.php?fips=00000 (verified November 15, 2011).Google Scholar