Digital Commons Network^™

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, …

Simulating Management Effects On Crop Production, Tile Drainage, And Water Quality Using Rzwqm–Dssat, S. A. Saseendran, Liwang Ma, Robert W. Malone, Philip Heilman, Lajpat R. Ahuja, Ramesh S. Kanwar, Douglas L. Karlen, G. Hoogenboom

Douglas L Karlen

The objective of this study was to explore if more crop-specific plant growth modules can improve simulations of crop yields, and N in tile flow under different management practices compared with a generic plant growth module. We calibrated and evaluated the Root Zone Water Quality Model (RZWQM) with the Decision Support for Agrotechnology Transfer (DSSAT v3.5) plant growth modules (RZWQM–DSSAT) for simulating tillage (NT — no till, RT — ridge till, CP — chisel plow, and MP — moldboard plow), crop rotation {CC — continuous corn, and CS — corn (Zea mays L.)–soybean [Glycine max (L.) Merr.]}, and nitrogen (N) …

Impacts Of Swine Manure Application And Alternative N-Management Practices On Productivity, Sustainability And Water Quality, Rameshwar S. Kanwar, Douglas Karlen, Cynthia A. Cambardella, Thomas Moorman, Thomas R. Steinheimer, Thomas S. Colvin

Douglas L Karlen

In the fourth year of this ongoing project, the effects of nine N-management practices under different tillage and cropping systems were evaluated. Forty experimental plots equipped with individual sumps and subsurface drainage metering and monitoring devices were used for the study. Overall results indicate that manure application rates and methods can be successfully managed for corn-soybean systems without damaging the water quality if the appropriate amount of N from swine manure can be applied.

Evaluating And Predicting Agricultural Management Effects Under Tile Drainage Using Modified Apsim, Robert W. Malone, N. Huth, P. S. Carberry, Liwang Ma, Thomas C. Kaspar, Douglas L. Karlen, T. Meade, Ramesh S. Kanwar, Philip Heilman

Douglas L Karlen

An accurate and management sensitive simulation model for tile-drained Midwestern soils is needed to optimize the use of agricultural management practices (e.g., winter cover crops) to reduce nitrate leaching without adversely affecting corn yield. Our objectives were to enhance the Agricultural Production Systems Simulator (APSIM) for tile drainage, test the modified model for several management scenarios, and then predict nitrate leaching with and without winter wheat cover crop. Twelve years of data (1990–2001) from northeast Iowa were used for model testing. Management scenarios included continuous corn and corn–soybean rotations with single or split N applications. For 38 of 44 observations, …

Effects Of Liquid Swine Manure Applications On No3–N Leaching Losses To Subsurface Drainage Water From Loamy Soils In Iowa, Allah Bakhsh, Ramesh S. Kanwar, Douglas Karlen

Douglas L Karlen

Long-term applications of organic or inorganic sources of N to croplands can increase the leaching potential of nitrate–nitrogen (NO₃–N) for soils underlain by subsurface drainage “tile” network. A field study was conducted for 6 years (1993–1998) to determine the effects of liquid swine manure and urea ammonium nitrate (UAN) solution fertilizer applications on NO₃–N concentrations and NO₃–N losses with subsurface drainage water under continuous corn (Zea maize L.) and corn after soybean (Glycine max. L.) production systems. The field data collected at Iowa State University's northeastern research center near Nashua, Iowa, under …

Twelve‐Year Tillage And Crop Rotation Effects On Yields And Soil Chemical Properties In Northeast Iowa, Douglas L. Karlen, Elaine C. Berry, Thomas S. Colvin, Ramesh S. Kanwar

Douglas L Karlen

Long‐term tillage and crop management studies may be useful for determining crop production practices that are conducive to securing a sustainable agriculture. Objectives of this field study were to evaluate the combined effects of crop rotation and tillage practices on yield and changes in soil chemical properties after 12 years of research on the Clyde‐Kenyon‐Floyd soil association in northeastern Iowa. Continuous corn (Zea mays L.) and a corn‐soybean [Glycine max L. (Herr.)] rotation were grown using moldboard plowing, chisel plowing, ridge‐tillage, or no‐tillage methods. Tillage and crop rotation effects on soil pH, Bray P1, 1M NH4OAc exchangeable K, Ca, and …

Corn Stover Harvest Strategy Effects On Grain Yield And Soil Quality Indicators, Douglas L. Karlen, Stuart J. Birrell, Adam Wirt, Nathan Schock

Douglas L Karlen

The development of technologies to use cellulosic biomass as a feedstock for biofuel production was recognized as an important research focus because cellulose is a more widely-available feedstock than corn starch. Our objective was to compare various corn (Zea mays L.) stover harvest strategies to determine which would be most sustainable. A complete block design with 2 ha plots, each replicated three times, was imposed on a 50 ha (125 acre) Clarion-Nicollet- Webster soil Association site near Emmetsburg, Iowa, U.S.A. before harvesting the 2008 corn crop. Hand samples were collected from a 1.5 m2 area in each plot to establish …

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% …

Empirical Analysis And Prediction Of Nitrate Loading And Crop Yield For Corn–Soybean Rotations, Robert W. Malone, Liwang Ma, Douglas L. Karlen, T. Meade, D. Meek, Ramesh S. Kanwar, Jerry L. Hatfield

Douglas L Karlen

Nitrate nitrogen losses through subsurface drainage and crop yield are determined by multiple climatic and management variables. The combined and interactive effects of these variables, however, are poorly understood. Our objective is to predict crop yield, nitrate concentration, drainage volume, and nitrate loss in subsurface drainage from a corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) rotation as a function of rainfall amount, soybean yield for the year before the corn–soybean sequence being evaluated, N source, N rate, and timing of N application in northeastern Iowa, U.S.A. Ten years of data (1994–2003) from a long-term study …

Corn-Soybean And Alternative Cropping Systems Effects On No 3 -N Leaching Losses In Subsurface Drainage Water, Rameshwar S. Kanwar, Richard M. Cruse, Mohammadreza Ghaffarzadeh, Allah Bakhsh, Douglas Karlen, Theodore B. Bailey

Douglas L Karlen

Alternative cropping systems can improve resource use efficiency, increase corn grain yield, and help in reducing negative impacts on the environment. A 6-yr (1993 to 1998) field study was conducted at the Iowa State University’s Northeastern Research Center near Nashua, Iowa, to evaluate the effects of non-traditional cropping systems [strip inter cropping (STR)-corn (Zea mays L.)/soybean (Glycine max L.)/oats (Avina sativa L.)]; alfalfa rotation (ROT)-3-yr (1993 to 1995) alfalfa (Medicago sativa L.) followed by corn in 1996, soybean in 1997, and oats in 1998), and traditional cropping system (corn after soybean (CS) and soybean after corn (SC) on the flow …

Rzwqm Simulation Of Long-Term Crop Production, Water And Nitrogen Balances In Northeast Iowa, L. Ma, Robert W. Malone, Philip Heilman, Douglas L. Karlen, Ramesh S. Kanwar, Cynthia A. Cambardella, S. A. Saseendran, Lajpat R. Ahuja

Douglas L Karlen

Agricultural system models are tools to represent and understand major processes and their interactions in agricultural systems. We used the Root Zone Water Quality Model (RZWQM) with 26 years of data from a study near Nashua, IA to evaluate year to year crop yield, water, and N balances. The model was calibrated using data from one 0.4 ha plot and evaluated by comparing simulated values with data from 29 of the 36 plots at the same research site (six were excluded). The dataset contains measured tile flow that varied considerably from plot to plot so we calibrated total tile flow …

Evaluation Of Tillage And Crop Rotation Effects On Groundwater Quality—Nashua Project, Rameshwar S. Kanwar, Douglas Karlen, Thomas S. Colvin, William W. Simpkins, Vince J. Mcfadden

Douglas L Karlen

Sampling shows that agricultural chemicals are occurring increasingly in ground- and surface water in Iowa. The same trend has been reported throughout the United States; one study reported finding 73 pesticides in the groundwater of 34 states. Even pesticides known to be adsorbed to soil particles (and thus relatively immobile) have been found in a few sampled wells in trace concentrations. Nitrate-nitrogen (NO3-N) is the most common agricultural chemical found in groundwater. Nitrogen fertilizers and pesticides applied to the soil surface prior to and immediately following crop planting are particularly susceptible to surface runoff or leaching to groundwater through the …

Simulated N Management Effects On Corn Yield And Tile-Drainage Nitrate Loss, Robert W. Malone, Liwang Ma, Philip Heilman, Douglas L. Karlen, Ramesh S. Kanwar, Jerry L. Hatfield

Douglas L Karlen

Thoroughly tested simulation models are needed to help quantify the long-term effects of agriculture. We evaluated the Root Zone Water Quality Model (RZWQM) response to different N management strategies and then used the tested model with observed weather data from 1961–2003 to quantify long-term effects on corn (Zea mays L.) yield and flow weighted nitrate-N concentration in subsurface “tile” drainage water (Nconc). Fourteen years (1990–2003) of field data from 30, 0.4 ha plots in northeast Iowa were available for model testing. Annual crop yield, nitrate-N loss to subsurface “tile” drainage water (Nloss), Nconc, and subsurface “tile” drainage amount (drain) …

Tillage System Effects On 15-Year Carbon-Based And Simulated N Budgets In A Tile-Drained Iowa Field, Douglas L. Karlen, Ajay Kumar, Ramesh S. Kanwar, Cynthia A. Cambardella, Thomas S. Colvin

Douglas L Karlen

Tillage influences N fate and transport by changing soil structure, aeration, macropore continuity, plant-residue placement, and organic-matter mineralization rates. Our objective was to use 15-year N budgets to compare four primary tillage treatments for continuous corn (Zea mays L.) production on tile-drained Aquic Hapludolls (FAO: Haplic Phaeozems) in northeastern Iowa, USA. A carbon-based N budget used annual grain yield, grain-N concentrations measured in 1992, changes in surface-soil C content between 1977 and 1988 or 1992, surface-soil C : N ratios, and measurements of NO3–N lost in tile-drainage water. It accounted for 98, 104, 99, and 99% of the fertilizer N …

Effect Of Tillage, Crop Rotation And Innovative Nitrogen And Pesticide Management Practices On Productivity, Sustainability And Water Quality, Rameshwar S. Kanwar, Douglas Karlen, Cynthia A. Cambardella, Thomas B. Moorman, T. R. Steinheimer, Thomas S. Colvin

Douglas L Karlen

Better nitrogen (N) management practices can improve nitrogen uptake and possibly reduce nitrogen leaching to groundwater. More efficient herbicide use can decrease or eliminate the herbicide leaching losses to water sources. In this project, the effects of seven N management practices on water quality were evaluated after collecting data from 40 experimental plots. Lower rates of N application and strip and hay cropping systems help produce lower concentrations of NO3-N in the shallow groundwater in comparison with the higher rate of N application. Also, banding of herbicides has resulted in lower herbicide losses to shallow groundwater. The use of the …

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.

Topographic Control Of Asynchronous Glacial Advances: A Case Study From Annapurna, Nepal, B. Pratt-Sitaula, D. W. Burbank, A. M. Heimsath, Neil Humphrey, M. Oskin, J. Putkonen

Neil Humphrey

Differences in the timing of glacial advances, which are commonly attributed to climatic changes, can be due to variations in valley topography. Cosmogenic Be-10 dates from 24 glacial moraine boulders in 5 valleys define two age populations, late-glacial and early Holocene. Moraine ages correlate with paleoglacier valley hypsometries. Moraines in valleys with lower maximum altitudes date to the late-glacial, whereas those in valleys with higher maximum altitudes are early Holocene. Two valleys with similar equilibrium-line altitudes (ELAs), but contrasting ages, are aspect, such that spatial differences in climate can be excluded. A glacial mass-balance cellular automata model of these two …

Climb To The Ice, Richard Vaughan

Richard Vaughan

The article, originally presented as a lecture, discusses George Bird Grinnell's 1887 climb of the Montana glacier that eventually become known as Grinnell Glacier. Grinnell’s efforts to establish Glacier National Park are detailed. Grinnell's previously unpublished descriptions of the glacier and its surrounding area are analyzed by the author. Originally delivered as a lecture at the Montana History Conference, October 2, 2010. Full issue available at: http://issuu.com/um_crown_gye/docs/crownofthecontinent-autumn2012

To The Ice: George Bird Grinnell's 1887 Ascent Of Grinnell Glacier, Richard Vaughan

Richard Vaughan

This article discusses a climbing expedition undertaken by U.S. conservationist George Bird Grinnell to ascend what would come to be known as Grinnell Glacier in Montana. Grinnell’s efforts to establish Glacier National Park are detailed. Grinnell’s previously unpublished descriptions of the glacier and its surrounding area are analyzed by the author.

Estimation Of The Effects Of Climate Variability On Crop Yield In The Midwest Usa, Ruoyu Wang

Ruoyu Wang

Evaluation Of Acidified Ammonium Oxalate Technique For The Identification Of Schwertmannite In Soil Materials, Chamindra Vithana, Leigh A. Sullivan, Richard T. Bush, Edward D. Burton

Chamindra Vithana

No abstract provided.

Geology Of The Chester, Ridley, And Crum Watersheds – Violent Past, Tranquil Present, Walter Cressler

Walt Cressler

No abstract provided.

Disentangling Climatic And Anthropogenic Controls On Global Terrestrial Evapotranspiration Trends, Jiafu Mao, Wenting Fu, Xiaoying Shi, Daniel M. Ricciuto, Joshua B. Fisher, Robert E. Dickinson, Yaxing Wei, Willis Shem, Shilong Piao, Kaicun Wang, Christopher R. Schwalm, Hanqin Tian, Mingquan Mu, Altaf Arain, Philippe Ciais, Robert Cook, Yongdiu Dai, Daniel Hayes, Forrest M. Hoffman, Maoyi Huang, Suo Huang, Deborah N. Huntzinger, Akihiko Ito, Atul Jain, Anthony W. King, Huimin Lei, Chaoqun (Crystal) Lu, Huimin Lei, Anna M. Michalak, Changhui Peng, Shushi Peng, Benjamin Poulter, Kevin Schaefer, Elshin Jafarov, Peter E. Thornton, Weile Wang, Ning Zeng, Zhenzhong Zeng, Fang Zhao, Qiuan Zhu, Zaichun Zhu

Chaoqun (Crystal) Lu

We examined natural and anthropogenic controls on terrestrial evapotranspiration (ET) changes from 1982 to 2010 using multiple estimates from remote sensing-based datasets and process-oriented land surface models.A significant increasing trend of ET in each hemisphere was consistently revealed by observationally-constrained data and multi-model ensembles that considered historic natural and anthropogenic drivers. The climate impacts were simulated to determine the spatiotemporal variations in ET. Globally, risingCO2 ranked second in these models after the predominant climatic influences, and yielded decreasing trends in canopy transpiration and ET, especially for tropical forests and high-latitude shrub land. Increasing nitrogen deposition slightly amplified global ET via …

Cover Crop Biomass Production And Water Use In The Central Great Plains, David C. Nielsen, Drew J. Lyon, Gary W. Hergert, Robert K. Higgins, Johnathon D. Holman

David C. Nielsen

The water-limited environment of the semiarid Central Great Plains may not produce enough cover crop biomass to generate benefits associated with cover crop use in more humid regions. There have been reports that cover crops grown in mixtures produce more biomass with greater water use efficiency than single-species plantings. This study was conducted to determine differences in cover crop biomass production, water use efficiency, and residue cover between a mixture and single-species plantings. The study was conducted at Akron, CO, and Sidney, NE, during the 2012 and 2013 growing seasons under both rainfed and irrigated conditions. Water use, biomass, and …

Soil Water Potential Control Of The Relationship Between Moisture And Greenhouse Gas Fluxes In Corn-Soybean Field, Dinesh Panday, Nsalambi V. Nkongolo

Dinesh Panday

Long-Lived Pluvial Episodes During Deposition Of The Navajo Sandstone, David B. Loope, Clinton M. Rowe

David B. Loope

The Navajo Sandstone of the American Southwest was deposited at approximately 190 Ma in a giant, subtropical dune field near the western margin of Pangea. From this unit, we report thick intervals of dune cross-strata that were churned by insects and trampled by reptiles. Although dunes continued to migrate freely, the distribution of trace fossils shows that plant life in wet interdune areas sustained high levels of animal activity on the dunes for many thousands of years. We interpret this suite of structures as the record of a pluvial episode climatologically similar to the period of “greening” in the Sahara …

Wind Scour Of Navajo Sandstone At The Wave (Central Colorado Plateau, U.S.A.), David B. Loope, Winston M. Seiler, Joseph A. Mason, Marjorie A. Chan

David B. Loope

At the Wave, a photogenic landform on the Utah–Arizona border, modern, southwesterly, sand-carrying winds abrade the Navajo Sandstone. Abundant trains of centimeter-scale, transverse, upwind-facing treads and risers cut sedimentary structures at a high angle. Central to the formation of these erosional steps are crusts produced by microbes lying just beneath exposed sandstone surfaces. Treads and risers are present on the walls of smoothly curved troughs at the Wave, on the walls of nearby circular scour pits, and on bedrock domes found at the center of scour pits. Because of their locations and orientations, the large-scale troughs and scour pits could …

New Stratigraphic Subdivision, Depositional Environment, And Age Estimate For The Upper Cretaceous Djadokhta Formation, Southern Ulan Nur Basin, Mongolia, Demberelyin Dashzeveg, Lowell Dingus, David B. Loope, Carl C. Swisher Iii, Togtokh Dulam, Mark R. Sweeney

David B. Loope

Studies of key and newly discovered sections of the Upper Cretaceous Djadokhta Formation along the southern margin of the Ulan Nur Basin allow a new subdivision based on lithology. The formation and its members were mapped at both Bayn Dzak, an area that includes the Flaming Cliffs, and Tugrugyin Shireh, an area about 50 km to the northwest of Bayn Dzak. Stratigraphic sections at both localities were remeasured. The considerably enlarged formation comprises a lower Bayn Dzak Member, dominated by moderate reddish orange sands with subordinate mudstone units, and an upper Tugrugyin Member, composed of pale orange to light gray …

Burrows Dug By Large Vertebrates Into Rain-Moistened Middle Jurassic Sand Dunes: A Reply, David B. Loope

David B. Loope

Odier (2007) is concerned with two issues: (1) I did not cite his work on burrows in the Navajo Sandstones of southeastern Utah in my article (Loope 2006), and (2) he believes I amwrong in interpreting the structures preserved in the Entrada Sandstone as burrows. On the first issue, I failed to cite both his 2004 abstract and the newly published book that he sent me in October 2006. My article was accepted on June 12, 2006; I returned the proofs on August 23; and the issue was published online on October 4, 2006. The timing of these events makes …

Preservation And Erosion Of Theropod Tracks In Eolian Deposits: Examples From The Middle Jurassic Entrada Sandstone, Utah, U.S.A., Jesper Milán, David B. Loope

David B. Loope

The Middle Jurassic Entrada Sandstone, exposed near the town of Escalante, southern Utah, consists of large-scale cross-bedded eolian deposits that are interbedded with horizontally laminated sand sheets and thin sets of eolian cross-strata, representing periods with a moister climate. The flat-bedded units contain numerous tracks and trackways from small to large-sized theropod dinosaurs. These tracks are today exposed in several distinct erosional states, allowing detailed studies of track and undertrack formation in eolian deposits. Tracks that originally were emplaced on sloping surfaces show, in their present-day erosional state, a morphology distinct from those originally emplaced on horizontal surfaces. Further, the …