Marsden Long-Term Rotation Study
Title: The Marsden farm experiment: A long-term investigation of how cropping system diversification and crop-livestock integration affect sustainability
Location: Iowa State University Marsden Farm, Boone, Co., Iowa
Time Period: 2001-present
Research Team: Matt Liebman and Matt Woods
Project Description: Sustainable farming practices are intended to minimize the use of non-renewable resources, decrease the emission of pollutants into water and air, retain and regenerate soil, and protect human health. They are also intended to maintain or increase farm productivity and profitability while reducing reliance on purchased inputs. A central tenet of sustainable farming systems is that careful stewardship of diverse ecological communities can be used to replace a substantial portion of the mineral fertilizers, synthetic pesticides, and petrochemical energy used in conventional farming systems.
Since 2001, we have used a 9-hectare (22-acre) field experiment at the Iowa State University Marsden Farm to investigate how cropping system diversification and crop-livestock integration affect productivity, profitability, and environmental quality. Three systems have been compared within the experiment: a 2-year corn/soybean rotation, a 3-year corn/soybean/oat + red clover rotation, and a 4-year corn/soybean/oat + alfalfa/alfalfa rotation. The 3-year and 4-year systems have periodically received cattle manure. By 2006, each of the plots had passed through at least one complete cycle of its respective rotation system.
For the ‘core set’ of comparisons among experimental treatments, the 2-year corn-soybean system has been managed with conventional rates of mineral fertilizers and herbicides, whereas the more diverse 3-year and 4-year systems have been managed with lower rates of agrichemicals. The experiment has also been used for a number of short-term component studies investigating a wide range of factors that can affect agroecosystem performance, including weed seed consumption by mice and insects, nitrogen mineralization from soil organic matter, and weed and crop responses to different ‘technology packages’ involving crop genotypes (transgenic versus non-transgenic) and weed control regimes (broadcast herbicides versus banded herbicides plus interrow cultivation).
Key results that have emerged from the study are as follows:
- During the period of 2006-2016, mineral N fertilizer use was 86% and 91% lower, and herbicide use was 96% and 97% lower in the 3-year and 4-year systems, respectively, than in the 2-year system.
- Corn yield has averaged 4% higher (p<0.0003) and soybean yield has averaged 16% higher (p<0.0001) in the more diverse systems compared with the 2-year system.
- Weed management has generally been effective regardless of rotation, with weed biomass in corn and soybean averaging <22 kilograms per hectare (20 lb per acre) in all systems.
- Incidence and severity of sudden death syndrome, a key disease affecting soybean in the Corn Belt, have been markedly lower in the longer rotations than in the 2-year rotation.
- Three indicators of soil quality–particulate organic matter carbon, microbial biomass carbon, and potentially mineralizable nitrogen–were 22% to 51% higher in the 3-year and 4-year rotations than in the 2-year rotation.
- Spring (March-May) concentrations of nitrate in drainage water collected from corn in the more diverse systems were 57% lower (p<0.005) than from corn in the 2-year system.
- Soil erosion was 50% lower, fossil energy consumption was 60% lower, and freshwater toxicity associated with herbicide use was 93% lower in the more diverse systems than in the conventional system.
- During 2008-2016, increases in rotation length led to greater labor requirements and decreased gross revenue. However, production costs also dropped substantially as cropping system diversity increased. Consequently, net returns to land and management did not differ among systems (p=0.56, mean=$845 per hectare per year, $342 per acre year), though profitability tended to rise as rotation length increased.
Collectively, results of this long-term study indicate that diversification of conventional corn-soybean systems with small grains and forage legumes, coupled with integration of those systems with livestock, can allow for large reductions in the use of mineral fertilizers and herbicides and lead to less environmental damage, equivalent profitability, improved soil quality, and higher crop productivity. Thus, the diversified, integrated crop-livestock systems we have investigated are in many ways more sustainable than a conventionally managed corn-soybean rotation. Translating these potential gains in agricultural sustainability into broad-scale changes in the U.S. Corn Belt will likely depend on combinations of factors that include government policies, farmer confidence, technical support, and markets for ‘non-conventional’ products.
Publications: Chen, X., X. Wang, M. Liebman, M. Cavigelli, and M. Wander. 2014. Influence of soil quality on carbon mineralization response to residue and nitrogen fertilizer additions. PLOS ONE 9(7): e103720, doi:10.1371/journal.pone.0103720.
Cruse, M.J., M. Liebman, D.R. Raman, and M. Wiedenhoeft. 2010. Fossil energy use in conventional and low-external-input cropping systems. Agronomy Journal 102: 934-941, doi:10.2134/agronj2009.0457; erratum: doi:10.2134/agronj2009.0457er.
Davis, A.S., J.D. Hill, C.A. Chase, A.M. Johanns, and M. Liebman. 2012. Increasing cropping system diversity balances productivity, profitability and environmental health. PLoS ONE 7(10): e47149. doi:10.1371/journal.pone.0047149.
Gómez, R., M. Liebman, and G. Munkvold. 2013. Weed seed decay in conventional and diversified cropping systems. Weed Research 54: 13-25.
Gómez, R., M. Liebman, D.N. Sundberg, and C.A. Chase. 2012. Comparison of crop management strategies involving crop genotype and weed management practices in conventional and more diverse cropping systems. Renewable Agriculture and Food 28: 220-233.
Heggenstaller, A.H. and M. Liebman. 2006. Demography of Abutilon theophrasti and Setaria faberi in three crop rotation systems. Weed Research 46: 138-151.
Heggenstaller, A.H., F.D. Menalled, M. Liebman, and P.R. Westerman. 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.
Hunt, N., J. Hill, and M. Liebman. 2019. Cropping system diversity effects on nutrient discharge, soil erosion, and agronomic performance. Environmental Science and Technology, doi:10.1021/acs.est.8b02193.
Hunt, N., J. Hill, and M. Liebman. 2017. Reducing freshwater toxicity while maintaining weed control, profits, and productivity: effects of increased crop rotation diversity and reduced herbicide usage. Environmental Science and Technology 51: 1707–1717, doi:10.1021/acs.est.6b04086.
Jordan, N.R., and A.S. Davis. 2015. Middle-way strategies for sustainable intensification of agriculture. Bioscience 65: 513-519.
King, A.E., and K.S. Hofmockel. 2017. Diversified cropping systems support greater microbial cycling and retention of carbon and nitrogen. Agriculture, Ecosystems and Environment 240: 66-67.
Lazicki, P., M. Liebman, and M. Wander. 2016. Root parameters show how management alters resource distribution and soil quality in conventional and low-input cropping systems in central Iowa. PLOS ONE 11(10): e0164209, doi:10.1371/journal.pone.0164209.
Leandro, L.F.S., S. Eggenberger, C. Chen, J. Williams, G. Beattie, and M. Liebman. 2018. Cropping system diversification reduces severity and incidence of soybean sudden death syndrome caused by Fusarium virguliforme. Plant Disease 102, doi:10.1094/PDIS-11-16-1660-RE.
Liebman, M., B. Baraibar, Y. Buckley, D. Childs, S. Christensen, R. Cousens, H. Eizenberg, S. Heijting, D. Loddo, A. Merotto Jr., M. Renton, and M. Riemens. 2016. Ecologically sustainable weed management: How do we get from proof-of-concept to adoption? Ecological Applications 26: 1352–1369.
Liebman, M., L.R. Gibson, D.N. Sundberg, A.H. Heggenstaller, P.R. Westerman, C.A. Chase, R.G. Hartzler, F.D. Menalled, A.S. Davis, and P.M. Dixon. 2008. Agronomic and economic performance characteristics of conventional and low-external-input cropping systems in the central Corn Belt. Agronomy Journal 100: 600-610.
Liebman, M., M.J. Helmers, L.A. Schulte, and C.A. Chase. 2013. Using biodiversity to link agricultural productivity with environmental quality: results from three field experiments in Iowa. Renewable Agriculture and Food Systems 28: 115-128, doi:10.1017/S1742170512000300.
Liebman, M., Z.J. Miller, C.L. Williams, P.R. Westerman, P.M. Dixon, A.H. Heggenstaller, A.S. Davis, F.D. Menalled, and D.N. Sundberg. 2014. Fates of Setaria faberi and Abutilon theophrasti seeds in three crop rotation systems. Weed Research 54: 293–306.
Liebman, M. and L.A. Schulte. 2015. Enhancing agroecosystem performance and resilience through increased diversification of landscapes and cropping systems. Elementa: Science of the Anthropocene, doi:10.12952/journal.elementa.000041.
O’Rourke, M.E., A. Heggenstaller, M. Liebman, M.E. Rice. 2006. Post-dispersal weed seed predation by invertebrates in conventional and low-external-input crop rotation systems. Agriculture, Ecosystems and Environment 116: 280-288.
O’Rourke, M.E., M. Liebman, and M.E. Rice. 2008. Ground beetle (Coleoptera: Carabidae) assemblages in conventional and diversified crop rotation systems. Environmental Entomology 37: 121-130.
Osterholz, W., M. Liebman, and M.J. Castellano. 2018. Can soil nitrogen dynamics explain the yield benefit of crop diversification? Field Crops Research 291: 33-42, doi:10.1016/j.fcr.2018.01.026.
Osterholz, W.R., O. Rinot, M. Liebman, and M.J. Castellano. 2016. Can mineralization of soil organic matter meet maize nitrogen demand? Plant and Soil, doi:10.1007/s11104-016-3137-1.
Osterholz, W.R., O. Rinot, A. Shaviv, R. Linker, G. Sanford, J. Strock, M. Liebman, and M. Castellano. 2017. Predicting gross nitrogen mineralization and potentially mineralizable N using soil organic matter properties. Soil Science Society of America Journal, doi:10.2136/sssaj2017.02.0055.
Poffenbarger, H., G. Artz, G. Dahlke, W. Edwards, M. Hanna, J. Russell, H. Sellers, and M. Liebman. 2017. An economic analysis of integrated crop-livestock systems in Iowa, U.S.A. Agricultural Systems 157: 51-69, doi:10.1016/j.agsy.2017.07.001.
Poffenbarger, H.J., D.C. Olk, C. Cambardella, J. Kersey, M. Liebman, A. Mallarino, J. Six, and M.J. Castellano. 2020. Whole-profile soil organic matter content, composition, and stability under crop rotations differing in belowground inputs. Agriculture, Ecosystems, and Environment, doi:10.1016/j.agee.2019.106810.
Rinot, O., W. Osterholz, M.J. Castellano, R. Linker, M. Liebman, and A. Shaviv. 2018. Excitation–emission matrix fluorescence spectroscopy of water extractable organic matter to predict nitrogen mineralization rates in soil. Soil Science Society of America Journal, doi:10.2136/sssaj2017.06.0188.
Tomer, M.D. and M. Liebman. 2014. Nutrients in soil water under three rotational cropping systems, Iowa, USA. Agriculture, Ecosystems and Environment 186: 105-114.
Wattenburger, C.J., L.J. Halverson, and K.S. Hofmockel. 2019. Agricultural management affects root-associated microbiome recruitment over maize development. Phytobiomes Journal. doi: 10.1094/PBIOMES-03-19-0016-R.
Westerman, P.R., M. Liebman, F.D. Menalled, A.H. Heggenstaller, R.G. Hartzler, and P.M. Dixon. 2005. Are many little hammers effective? Velvetleaf population dynamics in two- and four-year crop rotation systems. Weed Science 53: 382-392.
Williams, C.L., M. Liebman, P.R. Westerman, J. Borza, D. Sundberg, and B. Danielson. 2009. Over-winter predation of Abutilon theophrasti and Setaria faberi seeds in arable land. Weed Research 49: 439–447.
Funders: USDA Agriculture and Food Research Initiative, Leopold Center for Sustainable Agriculture, Iowa Soybean Association, and Iowa Nutrient Research Center
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