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- Soil quality index (1)
- Soils and agronomy (1)
- Subsurface drainage (1)
- Sustainable feedstock production (1)
- Water quality (1)
Articles 1 - 25 of 25
Full-Text Articles in Agronomy and Crop Sciences
Drainage Water Quality Impacts Of Agricultural Management Practices: Effectof Manure Application Timing And Cover Crops, Brian Dougherty, Carl Pederson, Matt Helmers, Michelle Soupir, Dan Andersen, Antonio Mallarino, John Sawyer
Drainage Water Quality Impacts Of Agricultural Management Practices: Effectof Manure Application Timing And Cover Crops, Brian Dougherty, Carl Pederson, Matt Helmers, Michelle Soupir, Dan Andersen, Antonio Mallarino, John Sawyer
John E. Sawyer
A primary objective of this study is to evaluate the impact of various cropping and nutrient management systems on crop yields and drainage water quality. This progress report only includes the first-year corn grain yield results. Treatment comparisons include the impact of early fall vs. late fall vs. spring application of liquid swine manure, nitrification inhibitor with late fall swine manure application, cereal rye cover crop, and gypsum application. These comparisons will be conducted for multiple years and used to develop appropriate manure and nutrient management practices to minimize water contamination potential and enhance the use of swine manure as …
Maximum Soil Organic Carbon Storage In Midwest U.S. Cropping Systems When Crops Are Optimally Nitrogen-Fertilized, Hanna J. Poffenbarger, Daniel W. Barker, Matthew J. Helmers, Fernando E. Miguez, Daniel C. Olk, John E. Sawyer, Johan Six, Michael J. Castellano
Maximum Soil Organic Carbon Storage In Midwest U.S. Cropping Systems When Crops Are Optimally Nitrogen-Fertilized, Hanna J. Poffenbarger, Daniel W. Barker, Matthew J. Helmers, Fernando E. Miguez, Daniel C. Olk, John E. Sawyer, Johan Six, Michael J. Castellano
John E. Sawyer
Nitrogen fertilization is critical to optimize short-term crop yield, but its long-term effect on soil organic C (SOC) is uncertain. Here, we clarify the impact of N fertilization on SOC in typical maize-based (Zea mays L.) Midwest U.S. cropping systems by accounting for site-to-site variability in maize yield response to N fertilization. Within continuous maize and maize-soybean [Glycine max (L.) Merr.] systems at four Iowa locations, we evaluated changes in surface SOC over 14 to 16 years across a range of N fertilizer rates empirically determined to be insufficient, optimum, or excessive for maximum maize yield. Soil organic C balances …
Surface Waters: Ammonium Is Not Ammonia – Part 3, John E. Sawyer, Matthew J. Helmers
Surface Waters: Ammonium Is Not Ammonia – Part 3, John E. Sawyer, Matthew J. Helmers
John E. Sawyer
Two previous ICM News articles outlined the difference between ammonium and ammonia, the relationship between the two nitrogen forms, and the implication of a combined (ammonium-N plus ammonia-N) analysis related to water quality criteria for aquatic life and chlorination treatment for drinking water.This article focuses on the potential sourcing of ammonium and ammonia in surface waters. Ammonium and ammonia in surface water systems can originate from many sources, and are naturally occurring forms of nitrogen. Predominant sources will vary on a watershed or sub-watershed basis. Also, sources and concentrations are greatly influenced by hydrology, including timing and volume of water …
N Management Influences On N Losses Through Tile Lines, Gyles W. Randall, John E. Sawyer
N Management Influences On N Losses Through Tile Lines, Gyles W. Randall, John E. Sawyer
John E. Sawyer
Subsurface tile drainage from row-crop agricultural production systems has been identified as a major source of nitrate entering surface waters in the Mississippi River Basin. Tile drainage studies have been conducted on three drainage research facilities at two locations in Minnesota since 1973. Nutrient and crop management systems, including rate and time of nitrogen (N) application, N sources (fertilizer, dairy manure, and hog manure), nitrification inhibitors, cropping systems, and tillage systems have been evaluated to determine their agronomic and environmental characteristics. Results from these studies have been instrumental in the development of best management practices for nutrient management in Minnesota.
Equipment Considerations: Liquid Fertilizer, H. Mark Hanna, John E. Sawyer
Equipment Considerations: Liquid Fertilizer, H. Mark Hanna, John E. Sawyer
John E. Sawyer
A review of application equipment considerations can help ensure that your nitrogen fertilizer is properly applied. This article focuses on liquid fertilizers and is the last in a series of three articles (other two in April 9, 2001, Integrated Crop Management issue) about nitrogen fertilizer application and equipment. A primary consideration for equipment is the relatively high application volumes required. For example, a 150-lb N/acre application of 28 percent UAN solution requires an application of 50 gal/acre.
Equipment Considerations: Anhydrous Ammonia, H. Mark Hanna, John E. Sawyer
Equipment Considerations: Anhydrous Ammonia, H. Mark Hanna, John E. Sawyer
John E. Sawyer
Because of abnormal nitrogen fertilizer production, import, and supply this year and with perhaps a short spring application season, some crop producers may use a form of nitrogen fertilizer with which they are unaccustomed. A review of application equipment considerations can help ensure that your nitrogen fertilizer is properly applied. This article focuses on anhydrous ammonia and is the second in a series of three articles about nitrogen fertilizer application and equipment.
Equipment Considerations: Dry Granual Fertilizer, H. Mark Hanna, John E. Sawyer
Equipment Considerations: Dry Granual Fertilizer, H. Mark Hanna, John E. Sawyer
John E. Sawyer
A review of application equipment considerations can help ensure that your nitrogen fertilizer is properly applied. This article focuses on dry granular fertilizers and is the first in a series of three articles about nitrogen fertilizer application and equipment. Because of varying physical properties of dry fertilizer materials, it is important to consider material distribution across the swath as well as application rate.
Equipment Maintenance: Fertilizer Applicators, H. Mark Hanna, John E. Sawyer, Michael J. Tidman
Equipment Maintenance: Fertilizer Applicators, H. Mark Hanna, John E. Sawyer, Michael J. Tidman
John E. Sawyer
Winter is a good time for crop producers and fertilizer dealers to work out the kinks in fertilizer application equipment for economic, environmental, efficiency, and safety reasons. Properly working application equipment translates into getting the most out of every fertilizer dollar. Overapplying to compensate for poorly calibrated equipment wastes money and could mean nutrient-rich runoff and consequently, a potential water quality problem. This article provides some tips for maintaining your fertilizer application equipment.
Fertilizer And Swine Manure Management Systems: Impacts On Agronomic And Environmental Soil Phosphorus Tests And On Phosphorus Loss With Subsurface Drainage, Antonio P. Mallarino, John E. Sawyer, Jeremy Klatt, Rameshwar S. Kanwar, Carl H. Pederson, James L. Baker, Kenneth T. Pecinovsky
Fertilizer And Swine Manure Management Systems: Impacts On Agronomic And Environmental Soil Phosphorus Tests And On Phosphorus Loss With Subsurface Drainage, Antonio P. Mallarino, John E. Sawyer, Jeremy Klatt, Rameshwar S. Kanwar, Carl H. Pederson, James L. Baker, Kenneth T. Pecinovsky
John E. Sawyer
Manure or fertilizer can be used to supply the phosphorus (P) needs of crops. However, excess P application increases the risk of P loss from fields and of water quality impairment through increased algae growth. Poor water quality in many Iowa lakes has prompted questions about the impact of P management practices on P loss from fields and the effectiveness of using agronomic soil tests for environmental purposes.
Fertilizer And Swine Manure Management Systems: Impacts On Crop Production And Nitrate-Nitrogen Leaching With Subsurface Drainage, Rameshwar S. Kanwar, Carl H. Pederson, James L. Baker, Antonio P. Mallarino, John E. Sawyer, Kenneth T. Pecinovsky
Fertilizer And Swine Manure Management Systems: Impacts On Crop Production And Nitrate-Nitrogen Leaching With Subsurface Drainage, Rameshwar S. Kanwar, Carl H. Pederson, James L. Baker, Antonio P. Mallarino, John E. Sawyer, Kenneth T. Pecinovsky
John E. Sawyer
Nutrient losses from row-crop land can cause nonpoint source water quality problems and “impaired waters.” Nitrogen (N) losses due to nitrate (NO3) leaching cause drinking water problems and possibly increase hypoxia (low oxygen) problems in the Gulf of Mexico. Phosphorus (P) losses can cause eutrophication problems in surface waters (lakes, streams, and reservoirs) in Iowa where algal blooms decrease oxygen, kill fish, and result in murky and bad tasting water. The U.S. EPA and the Iowa Department of Natural Resources are developing nutrient criteria/standards and implementation plans to address TMDL’s (Total Maximum Daily Load) and to improve the quality of …
Farm Energy: Energy Consumption For Row Crop Production, H. Mark Hanna, John E. Sawyer, Dana Petersen
Farm Energy: Energy Consumption For Row Crop Production, H. Mark Hanna, John E. Sawyer, Dana Petersen
John E. Sawyer
This publication provides an overview of farm energy use related to corn and soybean production in Iowa. Three areas of row crop production--field operations, fertilizer and pesticide application, and artificial drying--are used to illustrate on-farm energy consumption.
Farm Energy: Energy Conservation In Corn Nitrogen Fertilization, John E. Sawyer, H. Mark Hanna, Dana Petersen
Farm Energy: Energy Conservation In Corn Nitrogen Fertilization, John E. Sawyer, H. Mark Hanna, Dana Petersen
John E. Sawyer
Optimum corn yields require nitrogen fertilization in most crop rotations, but the energy consumed during the production of nitrogen fertilizer is considerable. Learn more about maximizing economic, environmental, and energy returns for nitrogen and other fertilizers.
Annual Swine Manure Applications To Soybean Under Corn-Soybean Rotation, Allah Bakhsh, Rameshwar S. Kanwar, James L. Baker, John E. Sawyer, Antonio P. Mallarino
Annual Swine Manure Applications To Soybean Under Corn-Soybean Rotation, Allah Bakhsh, Rameshwar S. Kanwar, James L. Baker, John E. Sawyer, Antonio P. Mallarino
John E. Sawyer
The response of a corn-soybean rotation system receiving fall manure application to both corn and soybean is not well understood in terms of its impact on nitrate leaching to subsurface drainage water and crop yields. This field study was conducted from 2001 through 2005 with the key objective of determining the effects of manure application to both corn and soybean on NO3-N concentrations in subsurface drainage water and corn-soybean yields. The study was conducted on 0.4 ha plots instrumented with state-of-the-art subsurface drainage monitoring systems at the Iowa State University research center, Nashua, Iowa. Nitrogen application rates from liquid swine …
Application Checkpoints For Fall Ammonia, H. Mark Hanna, John E. Sawyer
Application Checkpoints For Fall Ammonia, H. Mark Hanna, John E. Sawyer
John E. Sawyer
Depending on postharvest field conditions, some producers will soon be considering anhydrous ammonia application. Using fall labor to apply fertilizer can be attractive but needs to be balanced with the potential for nutrient loss. To avoid conversion of anhydrous ammonia from ammonium to more leachable forms of nitrogen, application should be delayed until average soil temperature is below 50°F and trending lower. Measure the 4-inch soil temperature at near 10 a.m. or 7 p.m. or check Iowa State University's county soil temperatures and forecast.
Impact Of Swine Manure Applications On Nitrate And Phosphorus In Subsurface Drainage Water, Rameshwar S. Kanwar, James L. Baker, Carl H. Pederson, Antonio P. Mallarino, John E. Sawyer, Kenneth T. Pecinovsky
Impact Of Swine Manure Applications On Nitrate And Phosphorus In Subsurface Drainage Water, Rameshwar S. Kanwar, James L. Baker, Carl H. Pederson, Antonio P. Mallarino, John E. Sawyer, Kenneth T. Pecinovsky
John E. Sawyer
Nonpoint source nutrient pollution related to land application of manures is recognized as an important environmental and social issue for several reasons. First, manure from swine production facilities can have serious impacts on the quality of ground water resources. Second, several states are in the process of creating laws and/or regulations to reduce nitrogen (N) and phosphorus (P) loadings from manure to soil and water resources. Third, pollution of water resources from nutrients supplied by manure to croplands will help set parameters for developing public policies on the management of manure.
Impact Of Swine Manure Application On Water Quality, Rameshwar S. Kanwar, Carl H. Pederson, Matthew J. Helmers, John E. Sawyer, Antonio P. Mallarino
Impact Of Swine Manure Application On Water Quality, Rameshwar S. Kanwar, Carl H. Pederson, Matthew J. Helmers, John E. Sawyer, Antonio P. Mallarino
John E. Sawyer
Nonpoint source nutrient pollution related to land application of manures is recognized as an important environmental and social issue for several reasons. First,swine manure application to land can impact water quality. Second, several states are in the process of creating laws and/or regulations to reduce nitrogen and phosphorus loadings from manure to soil and water resources. Third, the quality of water resources will help set parameters for developing public policies on management of manure.
Influence Of Corn Stover Harvest On Soil Quality Assessments At Multiple Locations Across The U.S., Diane E. Stott, Virginia L. Jin, Thomas F. Ducey, Douglas L. Karlen, Gary E. Varvel, Jane M. F. Johnson, John M. Baker, Shannon L. Osborne, Jeff M. Novak, Paul R. Adler, Greg W. Roth, Stuart J. Birrell
Influence Of Corn Stover Harvest On Soil Quality Assessments At Multiple Locations Across The U.S., Diane E. Stott, Virginia L. Jin, Thomas F. Ducey, Douglas L. Karlen, Gary E. Varvel, Jane M. F. Johnson, John M. Baker, Shannon L. Osborne, Jeff M. Novak, Paul R. Adler, Greg W. Roth, Stuart J. Birrell
Douglas L Karlen
Corn (Zea mays L.) stover has been identified as a biofuel feedstock due to its abundance and a perception that the residues are unused trash material. However, corn stover and other plant residues play a role in maintaining soil quality (health) and enhancing productivity, thus use of this abundant material as feedstock must be balanced with the need to protect the vital soil resource. Plant residues provide physical protection against erosion by wind and water, contribute to soil structure, nutrient cycling, and help sustain the soil microbiota. Replicated plots were established on productive soils at several locations (IA, IN, MN, …
Drought Effects On Composition And Yield For Corn Stover, Mixed Grasses, And Miscanthus As Bioenergy Feedstocks, Rachel Emerson, Amber Hoover, Allison Ray, Jeffrey Lacey, Marnie Cortez, Courtney Payne, Douglas L. Karlen, Stuart J. Birrell, David A. Laird, Robert Kallenbach, Josh Egenolf, Matthew Sousek, Thomas Voigt
Drought Effects On Composition And Yield For Corn Stover, Mixed Grasses, And Miscanthus As Bioenergy Feedstocks, Rachel Emerson, Amber Hoover, Allison Ray, Jeffrey Lacey, Marnie Cortez, Courtney Payne, Douglas L. Karlen, Stuart J. Birrell, David A. Laird, Robert Kallenbach, Josh Egenolf, Matthew Sousek, Thomas Voigt
Douglas L Karlen
Drought conditions in 2012 were some of the most severe in recent history. The purpose of this study is to examine the impact of drought on quality, quantity, and theoretical ethanol yield (TEY) of three bioenergy feedstocks, corn stover, mixed grasses from Conservation Reserve Program lands, and Miscanthus ×giganteus. To assess drought effects on these feedstocks, samples from 2010 (minimal to no drought) and 2012 (severe drought) were compared from multiple locations in the US. In all feedstocks, drought significantly increased extractives and reduced structural sugars and lignin; subsequently, TEYs were reduced 10–15%. Biomass yields were significantly reduced …
U.S. Billion-Ton Update: Biomass Supply For A Bioenergy And Bioproducts Industry, Robert D. Perlack, Laurence M. Eaton, Anthony F. Turhollow Jr., Matt H. Langholtz, Craig C. Brandt, Mark E. Downing, Robin L. Graham, Lynn L. Wright, Jacob M. Kavkewitz, Anna M. Shamey, Richard G. Nelson, Bryce J. Stokes, William L. Rooney, David J. Muth Jr., J. Richard Hess, Jared M. Abodeely, Chad Hellwinckel, Danial De La Torre Ugarte, Daniel C. Yoder, James P. Lyon, Timothy G. Rials, Timothy A. Volk, Thomas S. Buchholz, Lawrence P. Abrahamson, Robert P. Anex, Thomas B. Voigt, William Berguson, Don E. Riemenschneider, Douglas Karlen, Jane M. F. Johnson, Robert B. Mitchell, Kenneth P. Vogel, Edward P. Richard Jr., John Tatarko, Larry E. Wagner, Kenneth E. Skog, Patricia K. Lebow, Dennis P. Dykstra, Marilyn A. Buford, Patrick D. Miles, D. Andrew Scott, James H. Perdue, Robert B. Rummer, Jamie Barbour, John A. Stanturf, David B. Mckeever, Ronald S. Zalesny Jr., Edmund A. Gee, P. Daniel Cassidy, David Lightle
U.S. Billion-Ton Update: Biomass Supply For A Bioenergy And Bioproducts Industry, Robert D. Perlack, Laurence M. Eaton, Anthony F. Turhollow Jr., Matt H. Langholtz, Craig C. Brandt, Mark E. Downing, Robin L. Graham, Lynn L. Wright, Jacob M. Kavkewitz, Anna M. Shamey, Richard G. Nelson, Bryce J. Stokes, William L. Rooney, David J. Muth Jr., J. Richard Hess, Jared M. Abodeely, Chad Hellwinckel, Danial De La Torre Ugarte, Daniel C. Yoder, James P. Lyon, Timothy G. Rials, Timothy A. Volk, Thomas S. Buchholz, Lawrence P. Abrahamson, Robert P. Anex, Thomas B. Voigt, William Berguson, Don E. Riemenschneider, Douglas Karlen, Jane M. F. Johnson, Robert B. Mitchell, Kenneth P. Vogel, Edward P. Richard Jr., John Tatarko, Larry E. Wagner, Kenneth E. Skog, Patricia K. Lebow, Dennis P. Dykstra, Marilyn A. Buford, Patrick D. Miles, D. Andrew Scott, James H. Perdue, Robert B. Rummer, Jamie Barbour, John A. Stanturf, David B. Mckeever, Ronald S. Zalesny Jr., Edmund A. Gee, P. Daniel Cassidy, David Lightle
Douglas L Karlen
The Report, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply (generally referred to as the Billion-Ton Study or 2005 BTS), was an estimate of “potential” biomass within the contiguous United States based on numerous assumptions about current and future inventory and production capacity, availability, and technology. In the 2005 BTS, a strategic analysis was undertaken to determine if U.S. agriculture and forest resources have the capability to potentially produce at least one billion dry tons of biomass annually, in a sustainable manner—enough to displace approximately 30% of the country’s present petroleum …
Corn Grain, Stover Yield And Nutrient Removal Validations At Regional Partnership Sites, Douglas L. Karlen, Stuart J. Birrell, Jane M. F. Johnson, Shannon L. Osborne, Thomas E. Schumacher, Gary E. Varvel, Richard B. Ferguson, Jeff M. Novak, James R. Fredrick, John M. Baker, John A. Lamb, Paul R. Adler, Greg W. Roth, Emerson D. Nafziger
Corn Grain, Stover Yield And Nutrient Removal Validations At Regional Partnership Sites, Douglas L. Karlen, Stuart J. Birrell, Jane M. F. Johnson, Shannon L. Osborne, Thomas E. Schumacher, Gary E. Varvel, Richard B. Ferguson, Jeff M. Novak, James R. Fredrick, John M. Baker, John A. Lamb, Paul R. Adler, Greg W. Roth, Emerson D. Nafziger
Douglas L Karlen
Corn (Zea mays L.) stover has been identified as a major feedstock for cellulosic bioenergy. This report summarizes grain and stover yield as well as N, P, and K removal at several Sun Grant Regional Partnership (SGRP) sites. National Agricultural Statistical Service (NASS) grain yields were used to assess the relevancy of plot-scale yields with county averages. Seasonal variation in weather patterns caused yields to differ substantially among sites and years. Nutrient removal estimates were significantly influenced by the sampling method (i.e. analysis of hand samples between physiologic maturity and grain harvest versus stover collected during the harvest operation). Based …
Monitoring Soil Quality To Assess The Sustainability Of Harvesting Corn Stover, Douglas L. Karlen, Gary E. Varvel, Jane M. F. Johnson, John M. Baker, Shannon L. Osborne, Jeff M. Novak, Paul R. Adler, Greg W. Roth, Stuart J. Birrell
Monitoring Soil Quality To Assess The Sustainability Of Harvesting Corn Stover, Douglas L. Karlen, Gary E. Varvel, Jane M. F. Johnson, John M. Baker, Shannon L. Osborne, Jeff M. Novak, Paul R. Adler, Greg W. Roth, Stuart J. Birrell
Douglas L Karlen
Harvesting feedstock for biofuel production must not degrade soil, water, or air resources. Our objective is to provide an overview of field research being conducted to quantify effects of harvesting corn (Zea mays L.) stover as a bioenergy feedstock. Coordinated field studies are being conducted near Ames, IA; St. Paul and Morris, MN; Mead, NE; University Park, PA; Florence, SC; and Brookings, SD., as part of the USDA-ARS Renewable Energy Assessment Project (REAP). A baseline soil quality assessment was made using the Soil Management Assessment Framework (SMAF). Corn grain and residue yield for two different stover harvest rates (∼50% …
Corn Response To Late-Spring Nitrogen Management In The Walnut Creek Watershed, Douglas L. Karlen, Ana L. Dinnes, Dan B. Jaynes, Charles R. Hurburgh Jr., Cynthia A. Cambardella, Thomas S. Colvin, Glen R. Rippke
Corn Response To Late-Spring Nitrogen Management In The Walnut Creek Watershed, Douglas L. Karlen, Ana L. Dinnes, Dan B. Jaynes, Charles R. Hurburgh Jr., Cynthia A. Cambardella, Thomas S. Colvin, Glen R. Rippke
Douglas L Karlen
A 400-ha subbasin study within the Walnut Creek watershed near Ames, IA, confirmed that using late-spring soil nitrate nitrogen (NO3–N) test (LSNT) fertilizer recommendations could significantly reduce NO3–N loss in drainage water, but detailed crop response was not reported. Herein we summarize corn (Zea mays L.) response to the LSNT program when implemented across the Clarion–Nicollet–Webster soil association. The LSNT was used to determine the recommended N fertilizer rate that was applied uniformly across each field except on check strips where zero or nonlimiting (>220 kg N ha−1) sidedress N was applied. …
Winter Grazing Of Corn Residues: Effects On Soil Properties And Subsequent Crop Yields From A Corn-Soybean Crop Rotation, W. Darrell Busby, James R. Russell, Douglas L. Karlen, L. James Secor, Brian Peterson, Carroll Olson, Shawn C. Shouse, Dallas L. Maxwell
Winter Grazing Of Corn Residues: Effects On Soil Properties And Subsequent Crop Yields From A Corn-Soybean Crop Rotation, W. Darrell Busby, James R. Russell, Douglas L. Karlen, L. James Secor, Brian Peterson, Carroll Olson, Shawn C. Shouse, Dallas L. Maxwell
Douglas L Karlen
Corn residues could be a good resource for winter cattle grazing. The study investigates whether winter grazing causes soil compaction and yield reduction in crops that are planted following grazing.
No Evidence That Bacillus Thuringiensis Genes And Their Products Influence The Susceptibility Of Corn Residue To Decomposition, R. Michael Lehman, Shannon L. Osborne, Kurt A. Rosentrater
No Evidence That Bacillus Thuringiensis Genes And Their Products Influence The Susceptibility Of Corn Residue To Decomposition, R. Michael Lehman, Shannon L. Osborne, Kurt A. Rosentrater
Kurt A. Rosentrater
The possibility that Bacillus thuringiensis (Bt) corn (Zea mays L.) residues resist decomposition compared to non-Bt residues would present direct (soil carbon turnover times) and indirect (changes in tillage practices) effects on carbon budgets in agricultural systems. We evaluated the relative decomposition of residue from two pairs of Bt and non-Bt corn hybrids from different seed manufacturers buried in the root zone of adjacent Bt and non-Bt corn plots over a period of 384 d. We found no persistent differences in residue decomposition among the different hybrids regardless of the seed manufacturer or the presence of the Bt genes (both …
No Differences In Decomposition Rates Observed Between Bacillus Thuringiensis And Non-Bacillus Thuringiensis Corn Residue Incubated In The Field, R. Michael Lehman, Shannon L. Osborne, Kurt A. Rosentrater
No Differences In Decomposition Rates Observed Between Bacillus Thuringiensis And Non-Bacillus Thuringiensis Corn Residue Incubated In The Field, R. Michael Lehman, Shannon L. Osborne, Kurt A. Rosentrater
Kurt A. Rosentrater
Recent speculation of slower residue decomposition for Bacillus thuringiensis (Bt) corn (Zea mays L.) hybrids compared with non-Bt corn hybrids has prompted investigative study. We evaluated the residue decomposition rates of Bt and non-Bt corn hybrids over a period of 22 mo under field conditions using the litter bag technique. The four corn hybrids used were (i) DKC60–16 (Bt+, Cry1Ab protein active against the leptidopteran European corn borer, event MON810), (ii) DKC60–12 (Bt+, Cry3Bb1 protein active against the coleopteran corn rootworm, event MON863), (iii) DKC60–14 (stacked Bt++, Cry1Ab and Cry3Bb1 proteins) and, (iv) DKC60–15 (Bt−, base genetics). The biochemical and …