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Full-Text Articles in Physical Sciences and Mathematics

Equation Chapter 1 Section 1 Corn Suitability Rating For Southern Highland Zone Of Tanzania - A Feasibility Assessment At The Tari-Uyole, Mbeya, Tanzania, Johnson Godlove Mtama, Charles Lee Burras, Balthazar Michael Msanya May 2020

Equation Chapter 1 Section 1 Corn Suitability Rating For Southern Highland Zone Of Tanzania - A Feasibility Assessment At The Tari-Uyole, Mbeya, Tanzania, Johnson Godlove Mtama, Charles Lee Burras, Balthazar Michael Msanya

Agronomy Publications

Corn productivity indices (CSR2T) for representative soils in the Southern Highland Zone of Tanzania were developed. The approaches used were derived from Iowa State University’s CSR2. Consistent with ISU, index points were applied to the pedon based on the USDA Soil Taxonomy subgroup, family particle size class, and available water holding capacity, solum depth and resilience to degradation characterizations. Additional index points were applied based on field conditions especially slope, erosion history and flooding or ponding risk in order to determine the inherent productivity potential of the soils in the work sites. The results were used to develop the ...


Combination Of Biological And Chemical Soil Tests Best Predict Maize Nitrogen Response, Marshall D. Mcdaniel, D. T. Walters, L. G. Bundy, X. Li, R. A. Drijber, John E. Sawyer, Michael J. Castellano, C. A. M. Laboski, P. C. Scharf, W. R. Horwath Jan 2020

Combination Of Biological And Chemical Soil Tests Best Predict Maize Nitrogen Response, Marshall D. Mcdaniel, D. T. Walters, L. G. Bundy, X. Li, R. A. Drijber, John E. Sawyer, Michael J. Castellano, C. A. M. Laboski, P. C. Scharf, W. R. Horwath

Agronomy Publications

Soil tests can help optimize nitrogen (N) fertilizer rates, thereby improving farmer profitability and environmental performance. In US Midwest maize (Zea mays) production, however, most soil N tests have limited accuracy to predict N fertilizer requirements. Here we tested the individual and combined ability of 30 soil tests (12 rapid N extractions, seven biological carbon or N tests, six long‐term incubation kinetic parameters, and five other routine soil tests), as well as environmental and management data, to predict maize response to N fertilizer across 56 site‐years in the US Midwest. Out of 30 soil tests, and across all ...


Soil Water Content, Grain Yield, And Crop Water Use With Crop Rotations And Cultural Practices, Upendra M. Sainju, Andrew W. Lenssen, Brett L. Allen, Jalal D. Jabro, William B. Stevens, William M. Iversen Jan 2020

Soil Water Content, Grain Yield, And Crop Water Use With Crop Rotations And Cultural Practices, Upendra M. Sainju, Andrew W. Lenssen, Brett L. Allen, Jalal D. Jabro, William B. Stevens, William M. Iversen

Agronomy Publications

Limited and erratic precipitation in arid and semiarid regions can affect soil water storage, water use, and dryland crop performance. Our objective was to examine soil water content, crop yield, and water‐use efficiency (WUE) with crop rotations and cultural practices for six years in the northern Great Plains. Crop rotations were durum wheat (or durum) (Triticum turgidum L.)‐durum‐canola (Brassica napus L.)‐pea (Pisum sativum L.) (DDCP), durum‐durum‐flax (Linum usitatissimum L.)‐pea (DDFP), durum‐canola‐durum‐pea (DCDP), and durum‐flax‐durum‐pea (DFDP). A continuous durum (CD) was also included for comparison. Cultural practices were ...


Whole-Profile Soil Organic Matter Content, Composition, And Stability Under Cropping Systems That Differ In Belowground Inputs, Hanna J. Poffenbarger, Daniel C. Olk, Cynthia Cambardella, Jordan Kersey, Matthew Z. Liebman, Antonio Mallarino, Johan Six, Michael J. Castellano Jan 2020

Whole-Profile Soil Organic Matter Content, Composition, And Stability Under Cropping Systems That Differ In Belowground Inputs, Hanna J. Poffenbarger, Daniel C. Olk, Cynthia Cambardella, Jordan Kersey, Matthew Z. Liebman, Antonio Mallarino, Johan Six, Michael J. Castellano

Agronomy Publications

Subsoils have been identified as a potential carbon sink because they typically have low soil organic carbon (SOC) concentrations and high SOC stability. One proposed strategy to increase SOC stocks is to enhance C inputs to the subsoil by increasing crop rotation diversity with deep-rooted perennial crops. Using three long-term field trials in Iowa (study durations of 60, 35, and 12 years), we examined the effects of contrasting cropping systems [maize (Zea mays L.)-soybean (Glycine max (L.) Merr) (= two-year system) vs. maize-soybean-oat (Avena sativa L.)/alfalfa (Medicago sativa L.)-alfalfa or maize-maize-oat/alfalfa-alfalfa (= four-year system)] on above- and below-ground ...


Predicting Crop Yields And Soil‐Plant Nitrogen Dynamics In The Us Corn Belt, Sotirios V. Archontoulis, Michael J. Castellano, Mark A. Licht, Virginia Nichols, Mitch Baum, Isaiah Huber, Rafael Martinez-Feria, Laila Puntel, Raziel A. Ordonez, Javed Iqbal, Emily E. Wright, Ranae N. Dietzel, Matthew Helmers, Andy Vanloocke, Matt Liebman, Jerry L. Hatfield, Daryl Herzmann, S. Carolina Córdova, Patrick Edmonds, Kaitlin Togliatti, Ashlyn Kessler, Gerasimos Danalatos, Heather Pasley, Carl Pederson, Kendall R. Lamkey Jan 2020

Predicting Crop Yields And Soil‐Plant Nitrogen Dynamics In The Us Corn Belt, Sotirios V. Archontoulis, Michael J. Castellano, Mark A. Licht, Virginia Nichols, Mitch Baum, Isaiah Huber, Rafael Martinez-Feria, Laila Puntel, Raziel A. Ordonez, Javed Iqbal, Emily E. Wright, Ranae N. Dietzel, Matthew Helmers, Andy Vanloocke, Matt Liebman, Jerry L. Hatfield, Daryl Herzmann, S. Carolina Córdova, Patrick Edmonds, Kaitlin Togliatti, Ashlyn Kessler, Gerasimos Danalatos, Heather Pasley, Carl Pederson, Kendall R. Lamkey

Agronomy Publications

We used the Agricultural Production Systems sIMulator (APSIM) to predict and explain maize and soybean yields, phenology, and soil water and nitrogen (N) dynamics during the growing season in Iowa, USA. Historical, current and forecasted weather data were used to drive simulations, which were released in public four weeks after planting. In this paper, we (1) describe the methodology used to perform forecasts; (2) evaluate model prediction accuracy against data collected from 10 locations over four years; and (3) identify inputs that are key in forecasting yields and soil N dynamics. We found that the predicted median yield at planting ...


Establishing Winter Annual Cover Crops By Interseeding Into Maize And Soybean, Yesuf Assen Mohammed, Heather L. Matthees, Russ W. Gesch, Swetabh Patel, Frank Forcella, Kyle Aasand, Nicholas Steffl, Burton L. Johnson, M. Scott Wells, Andrew W. Lenssen Jan 2020

Establishing Winter Annual Cover Crops By Interseeding Into Maize And Soybean, Yesuf Assen Mohammed, Heather L. Matthees, Russ W. Gesch, Swetabh Patel, Frank Forcella, Kyle Aasand, Nicholas Steffl, Burton L. Johnson, M. Scott Wells, Andrew W. Lenssen

Agronomy Publications

The limited time available for cover crop establishment after maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] harvest is one of the main reasons for low cover crop adoption in the upper Midwest. Therefore, a 2‐yr multilocation study was conducted to evaluate winter annual cover crops establishment, their effect on main crop grain yields, and soil water content when interseeded into standing maize and soybean. Treatments were three interseeding dates (broadcasting at R4, R5, and R6 growth stages for maize, and R6, R7, and R8 for soybean) and three cover crops (winter camelina [WC] [Camelina sativa L ...


Stacked Crop Rotations And Cultural Practices For Canola And Flax Yield And Quality, Upendra M. Sainju, Andrew W. Lenssen, Brett L. Allen, Jalal D. Jabro, William B. Stevens Jan 2020

Stacked Crop Rotations And Cultural Practices For Canola And Flax Yield And Quality, Upendra M. Sainju, Andrew W. Lenssen, Brett L. Allen, Jalal D. Jabro, William B. Stevens

Agronomy Publications

Canola (Brassica napus L.) and flax (Linum usitatissimum L.) are important oilseed crops, but improved management practices to enhance their yields and quality are needed. We studied the effect of stacked versus alternate‐year crop rotations and traditional versus improved cultural practices on canola and flax growth, seed yield, oil concentration, and N‐use efficiency from 2006 to 2011 in the northern Great Plains, USA. Stacked rotations were durum (Triticum turgidum L.)‐durum‐canola‐pea (Pisum sativum L.) (DDCP) and durum‐durum‐flax ‐pea (DDFP). Alternate‐year rotations were durum‐canola‐durum‐pea (DCDP) and durum‐flax‐durum‐pea (DFDP ...


Soil Sample Timing, Nitrogen Fertilization, And Incubation Length Influence Anaerobic Potentially Mineralizable Nitrogen, Jason D. Clark, Kristen S. Veum, Fabián G. Fernández, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, David W. Franzen, Daniel E. Kaiser, Carrie A. M. Laboski, Emerson D. Nafziger, Carl J. Rosen, John E. Sawyer, John F. Shanahan Jan 2020

Soil Sample Timing, Nitrogen Fertilization, And Incubation Length Influence Anaerobic Potentially Mineralizable Nitrogen, Jason D. Clark, Kristen S. Veum, Fabián G. Fernández, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, David W. Franzen, Daniel E. Kaiser, Carrie A. M. Laboski, Emerson D. Nafziger, Carl J. Rosen, John E. Sawyer, John F. Shanahan

Agronomy Publications

Understanding the variables that affect the anaerobic potentially mineralizable N (PMNan) test should lead to a standard procedure of sample collection and incubation length, improving PMNan as a tool in corn (Zea mays L.) N management. We evaluated the effect of soil sample timing (preplant and V5 corn development stage [V5]), N fertilization (0 and 180 kg ha−1) and incubation length (7, 14, and 28 d) on PMNan (0–30 cm) across a range of soil properties and weather conditions. Soil sample timing, N fertilization, and incubation length affected PMNan differently based on soil and weather conditions. Preplant vs ...


Adjusting Corn Nitrogen Management By Including A Mineralizable‐Nitrogen Test With The Preplant And Presidedress Nitrate Tests, Jason D. Clark, Fabián G. Fernández, Kristen S. Veum, James J. Camberato, Paul R. Carter, Richard B. Ferguson, David W. Franzen, Daniel E. Kaiser, Newell R. Kitchen, Carrie A. M. Laboski, Emerson D. Nafziger, Carl J. Rosen, John E. Sawyer, John F. Shanahan Jan 2020

Adjusting Corn Nitrogen Management By Including A Mineralizable‐Nitrogen Test With The Preplant And Presidedress Nitrate Tests, Jason D. Clark, Fabián G. Fernández, Kristen S. Veum, James J. Camberato, Paul R. Carter, Richard B. Ferguson, David W. Franzen, Daniel E. Kaiser, Newell R. Kitchen, Carrie A. M. Laboski, Emerson D. Nafziger, Carl J. Rosen, John E. Sawyer, John F. Shanahan

Agronomy Publications

The anaerobic potentially mineralizable N (PMN) test combined with the preplant (PPNT) and presidedress (PSNT) nitrate tests may improve corn (Zea mays L.) N fertilization predictions. Forty‐nine corn N response experiments (mostly corn following soybean [Glycine max (L.) Merr.]) were conducted in the U.S. Midwest from 2014–2016 to evaluate the ability of the PPNT and PSNT to predict corn relative yield (RY) and N fertilizer over‐ and under‐application rates when adjusted by PMN. Before planting and N fertilization, PPNT (0–30, 30–60, and 60–90 cm) and PMN (0–30 cm) samples were obtained. In ...


Corn Yield Response To Row Spacing And Plant Population In Iowa, Mark A. Licht, M. R. Parvej, Emily E. Wright Nov 2019

Corn Yield Response To Row Spacing And Plant Population In Iowa, Mark A. Licht, M. R. Parvej, Emily E. Wright

Agronomy Publications

Corn (Zea mays L.) planted in narrow row spacing (<30-inch) with high plant population has become a recent interest in the US Corn Belt to increase grain yield. We evaluated the impact of row spacing and plant population on corn grain yield across 22 site-years in Iowa from 2009 to 2018. Experiments were designed as a split-plot with two row spacings, 20- and 30-inch, as the main-plot and three to four plant populations, ranging from 30,000 to 42,000 plants acre–1, as subplot. Grain yield was affected in 73% of the site-years: 13 site-years by row spacing, six site-years by plant population, and 2 site-years by the interaction of both. Corn in 20-inch rows yielded 5 to 19 bu acre–1 more in 11 site-years and 10 to 14 bu acre–1 less in two site-years compared to 30-inch rows. In both 20- and 30-inch row spacings, corn yield decreased linearly at 0.4 to 1.7 bu acre–1 per thousand increase in plant population in four site-years and responded ...


Sustainable Intensification Of Agricultural Drainage, Michael J. Castellano, Sotirios V. Archontoulis, Matthew J. Helmers, Hanna J. Poffenbarger, Johan Six Oct 2019

Sustainable Intensification Of Agricultural Drainage, Michael J. Castellano, Sotirios V. Archontoulis, Matthew J. Helmers, Hanna J. Poffenbarger, Johan Six

Agronomy Publications

Artificial drainage is among the most widespread land improvements for agriculture. Drainage benefits crop production, but also promotes nutrient losses to water resources. Here, we outline how a systems perspective for sustainable intensification of drainage can mitigate nutrient losses, increase fertilizer nitrogen use efficiency (NUE) and reduce greenhouse gas emissions. There is an immediate opportunity to realize these benefits because agricultural intensification and climate change are increasing the extent and intensity of drainage systems. If a systems-based approach to drainage can consistently increase NUE while maintaining or increasing crop production, farmers and the environment will benefit.


Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabián G. Fernández, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan Sep 2019

Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabián G. Fernández, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan

Agronomy Publications

Nitrogen (N) fertilizer recommendation tools could be improved for estimating corn (Zea mays L.) N needs by incorporating site-specific soil and weather information. However, an evaluation of analytical methods is needed to determine the success of incorporating this information. The objectives of this research were to evaluate statistical and machine learning (ML) algorithms for utilizing soil and weather information for improving corn N recommendation tools. Eight algorithms [stepwise, ridge regression, least absolute shrinkage and selection operator (Lasso), elastic net regression, principal component regression (PCR), partial least squares regression (PLSR), decision tree, and random forest] were evaluated using a dataset containing ...


Does Diversifying Crop Rotations Suppress Weeds? A Meta-Analysis, David Weisberger, Virginia Nichols, Matt Liebman Jul 2019

Does Diversifying Crop Rotations Suppress Weeds? A Meta-Analysis, David Weisberger, Virginia Nichols, Matt Liebman

Agronomy Publications

Over the past half-century, crop rotations have become increasingly simplified, with whole regions producing only one or two crops in succession. Simplification is problematic from a weed management perspective, because it results in weeds’ repeated exposure to the same set of ecological and agronomic conditions. This can exacerbate weed infestations and promote the evolution of herbicide resistance. Diversifying crop rotations through addition of crop species and their associated managements may suppress weeds and reduce selection pressure for herbicide resistance by altering stress and mortality factors affecting weed dynamics. Here we report the results of a meta-analysis using 298 paired observations ...


Enhancing Apsim To Simulate Excessive Moisture Effects On Root Growth, Elnaz Ebrahimi-Mollabashi, Neil I. Huth, Dean P. Holzwoth, Raziel A. Ordonez, Jerry L. Hatfield, Isaiah Huber, Michael J. Castellano, Sotirios V. Archontoulis Apr 2019

Enhancing Apsim To Simulate Excessive Moisture Effects On Root Growth, Elnaz Ebrahimi-Mollabashi, Neil I. Huth, Dean P. Holzwoth, Raziel A. Ordonez, Jerry L. Hatfield, Isaiah Huber, Michael J. Castellano, Sotirios V. Archontoulis

Agronomy Publications

Shallow water table (WT) influences crop growth and production in many major agricultural regions across the globe. We enhanced the APSIM-soybean model to accurately simulate root depth in fields with shallow water tables. We used data from a controlled experiment (Rhizotron facilities) that included root depth observations for nine WT treatments to develop and calibrate the new model. Analysis indicated that unconstrained root growth occurs until volumetric soil moisture approaches 0.03 mm/mm below saturation. Below that threshold, root growth linearly decreases to zero at saturation. Inclusion of this factor into the model increased accuracy of root depth simulations ...


Nitrogen Fertilizer Suppresses Mineralization Of Soil Organic Matter In Maize Agroecosystems, Navreet K. Mahal, William R. Osterholz, Fernando E. Miguez, Hanna J. Poffenbarger, John E. Sawyer, Daniel C. Olk, Sotirios V. Archontoulis, Michael J. Castellano Mar 2019

Nitrogen Fertilizer Suppresses Mineralization Of Soil Organic Matter In Maize Agroecosystems, Navreet K. Mahal, William R. Osterholz, Fernando E. Miguez, Hanna J. Poffenbarger, John E. Sawyer, Daniel C. Olk, Sotirios V. Archontoulis, Michael J. Castellano

Agronomy Publications

The possibility that N fertilizer increases soil organic matter (SOM) mineralization and, as a result, reduces SOM stocks has led to a great debate about the long-term sustainability of maize-based agroecosystems as well as the best method to estimate fertilizer N use efficiency (FNUE). Much of this debate is because synthetic N fertilizer can positively or negatively affect SOM mineralization via several direct and indirect pathways. Here, we test a series of hypotheses to determine the direction, magnitude, and mechanism of N fertilizer effect on SOM mineralization and discuss the implications for methods to estimate FNUE.Wemeasured the effect of ...


The Iowa Atmospheric Observatory: Revealing The Unique Boundary-Layer Characteristics Of A Wind Farm, Eugene S. Takle, Daniel A. Rajewski, Samantha L. Purdy Jan 2019

The Iowa Atmospheric Observatory: Revealing The Unique Boundary-Layer Characteristics Of A Wind Farm, Eugene S. Takle, Daniel A. Rajewski, Samantha L. Purdy

Agronomy Publications

The Iowa Atmospheric Observatory was established to better understand the unique microclimate characteristics of a wind farm. The facility consists of a pair of 120 m towers identically instrumented to observe basic landscape-atmosphere interactions in a highly managed agricultural landscape. The towers, one within and one outside of a utility-scale low-density array wind farm, are equipped to measure vertical profiles of temperature, wind, moisture, and pressure and can host specialized sensors for a wide range of environmental conditions. Tower measurements during the 2016 growing season demonstrate the ability to distinguish microclimate differences created by single or multiple turbines from natural ...


Planting Date, Hybrid Maturity, And Weather Effects On Maize Yield And Crop Stage, M. E. Baum, S. V. Archontoulis, M. A. Licht Jan 2019

Planting Date, Hybrid Maturity, And Weather Effects On Maize Yield And Crop Stage, M. E. Baum, S. V. Archontoulis, M. A. Licht

Agronomy Publications

Unfavorable weather conditions frequently cause farmers to plant maize (Zea mays L.) outside the optimum planting timeframe. We analyzed maize yield and phenology from a multilocation, year, hybrid relative maturity, and planting date experiment performed in Iowa, USA. Our objectives were to determine the optimum combination of planting date and relative maturity to maximize maize grain yield per environment and to elucidate the risk associated with the use of “full-season hybrids” when planting occurs beyond the optimum planting date. Analysis of variance (ANOVA) attributed 70% of the variability in grain yield to planting date and only 10% to relative maturity ...


Pea Growth, Yield, And Quality In Different Crop Rotations And Cultural Practices, Upendra M. Sainju, Andrew W. Lenssen, Brett L. Allen, Jalal D. Jabro, William B. Stevens Jan 2019

Pea Growth, Yield, And Quality In Different Crop Rotations And Cultural Practices, Upendra M. Sainju, Andrew W. Lenssen, Brett L. Allen, Jalal D. Jabro, William B. Stevens

Agronomy Publications

Dryland pea (Pisum sativum L.) is an important pulse crop that can replace fallow or be added to existing crop rotations to sustain crop yields in arid and semiarid regions. Yet, we lack management practices to enhance yield and quality of dryland pea. This study evaluated the effect of crop rotation and cultural practices on dryland pea growth, yield, and quality from 2006 to 2011 in the northern Great Plains, USA. Stacked rotations were durum (Triticum turgidum L.)–durum–canola (Brassica napus L.)–pea (DDCP) and durum–durum–flax (Linum usitatissimum L.)–pea (DDFP), and alternate-year rotations were durum–canola ...


Soil Water Retention And Hydraulic Conductivity Dynamics Following Tillage, D. Kool, B. Tong, Z. Tian, J. L. Heitman, T. J. Sauer, R. Horton Jan 2019

Soil Water Retention And Hydraulic Conductivity Dynamics Following Tillage, D. Kool, B. Tong, Z. Tian, J. L. Heitman, T. J. Sauer, R. Horton

Agronomy Publications

Soil bulk density (ρb) may be purposely reduced in agricultural fields using tillage to improve hydraulic properties. However, tillage alters the soil structure, resulting in unstable soils. As the soil stabilizes, ρb increases over time. While this is known, studies on soil hydraulic properties in tilled soils, including comparisons between tilled and non-tilled soils, commonly assume a rigid soil structure. This study presents changes in soil water retention and saturated hydraulic conductivity (Ksat) as ρb increased dynamically with time following tillage at a loam-textured field site. Over the summer of 2015, soil cores were collected at ...


Regenerating Agricultural Landscapes With Perennial Groundcover For Intensive Crop Production, Kenneth J. Moore, Robert P. Anex, Amani E. Elobeid, Shuizhang Fei, Cornelia B. Flora, A. Susana Goggi, Keri L. Jacobs, Prashant Jha, Amy L. Kaleita, Douglas L. Karlen, David A. Laird, Andrew W. Lenssen, Thomas Lubberstedt, Marshall D. Mcdaniel, D. Raj Raman, Sharon L. Weyers Jan 2019

Regenerating Agricultural Landscapes With Perennial Groundcover For Intensive Crop Production, Kenneth J. Moore, Robert P. Anex, Amani E. Elobeid, Shuizhang Fei, Cornelia B. Flora, A. Susana Goggi, Keri L. Jacobs, Prashant Jha, Amy L. Kaleita, Douglas L. Karlen, David A. Laird, Andrew W. Lenssen, Thomas Lubberstedt, Marshall D. Mcdaniel, D. Raj Raman, Sharon L. Weyers

Agronomy Publications

The Midwestern U.S. landscape is one of the most highly altered and intensively managed ecosystems in the country. The predominant crops grown are maize (Zea mays L.) and soybean [Glycine max (L.) Merr]. They are typically grown as monocrops in a simple yearly rotation or with multiple years of maize (2 to 3) followed by a single year of soybean. This system is highly productive because the crops and management systems have been well adapted to the regional growing conditions through substantial public and private investment. Furthermore, markets and supporting infrastructure are highly developed for both crops. As maize ...


Maize Root Distributions Strongly Associated With Water Tables In Iowa, Usa, Virginia A. Nichols, Raziel A. Ordonez, Emily E. Wright, Michael J. Castellano, Matt Liebman, Jerry L. Hatfield, Matt Helmers, Sotirios V. Archontoulis Jan 2019

Maize Root Distributions Strongly Associated With Water Tables In Iowa, Usa, Virginia A. Nichols, Raziel A. Ordonez, Emily E. Wright, Michael J. Castellano, Matt Liebman, Jerry L. Hatfield, Matt Helmers, Sotirios V. Archontoulis

Agronomy Publications

No abstract provided.


Application Of A Formulated Humic Product Can Increase Soybean Yield, Andrew W. Lenssen, Daniel C. Olk, Dana L. Dinnes Jan 2019

Application Of A Formulated Humic Product Can Increase Soybean Yield, Andrew W. Lenssen, Daniel C. Olk, Dana L. Dinnes

Agronomy Publications

Application of humic products to crops remains controversial. We conducted a field study in Iowa over four environments from 2012 to 2014 examining productivity of soybean [Glycine max (L.) Merr.] receiving foliar application of a humic product at one of four application times based on plant development. Humic product application never influenced soybean height at harvest. Soybean yield increased following application of the humic product in two of four environments, but application timing was not completely consistent between these two environments. In one 2012 environment, humic product application at V2, V6, and R2 resulted in greater yield than the untreated ...


Climate Warming Trends In The U.S. Midwest Using Four Thermal Models, Lori J. Abendroth, Fernando E. Miguez, Michael J. Castellano, Jerry L. Hatfield Jan 2019

Climate Warming Trends In The U.S. Midwest Using Four Thermal Models, Lori J. Abendroth, Fernando E. Miguez, Michael J. Castellano, Jerry L. Hatfield

Agronomy Publications

Thermal time (TT) is an agro-climate index widely established and used in predicting plant development based on temperature. This index is a powerful tool for measuring multi-faceted changes in temperature occurring from climate change. In the present study, TT was calculated for the entire frost-free period and individual spring, summer, and fall seasons using growing degree day (GDD), general thermal index (GTI), crop heat unit (CHU), and heat stress degree day (HSDD) models for 1054 counties across 12 Midwest states on a daily basis from 1950 to 2017. The temporal trend for each county was fit with a linear regression ...


Soil Carbon Increased By Twice The Amount Of Biochar Carbon Applied After Six Years: Field Evidence Of Negative Priming, Humberto Blanco-Canqui, David Laird, Emily Heaton, Sam Rathke, Bharat Sharma Acharya Jan 2019

Soil Carbon Increased By Twice The Amount Of Biochar Carbon Applied After Six Years: Field Evidence Of Negative Priming, Humberto Blanco-Canqui, David Laird, Emily Heaton, Sam Rathke, Bharat Sharma Acharya

Agronomy Publications

Applying biochar to agricultural soils has been proposed as a means of sequestering C while simultaneously enhancing soil health and agricultural sustainability. However, our understanding of the long-term effects of biochar and annual versus perennial cropping systems and their interactions on soil properties under field conditions is limited. We quantified changes in soil C concentration and stocks and other soil properties 6 yr after biochar applications to corn (Zea mays L.) and dedicated bioenergy crops on a Midwestern US soil. Treatments were: no-till continuous corn, Liberty switchgrass (Panicum virgatum L.), and low diversity prairie grasses, 45% big bluestem (Andropogon gerardii ...


Multi-Year And Multi-Site Establishment Of The Perennial Biomass Crop Miscanthus × Giganteus Using A Staggered Start Design To Elucidate N Response, Mauricio Tejera, Nicholas Boersma, Andy Vanloocke, Sotirios Archontoulis, Philip Dixon, Fernando Miguez, Emily Heaton Jan 2019

Multi-Year And Multi-Site Establishment Of The Perennial Biomass Crop Miscanthus × Giganteus Using A Staggered Start Design To Elucidate N Response, Mauricio Tejera, Nicholas Boersma, Andy Vanloocke, Sotirios Archontoulis, Philip Dixon, Fernando Miguez, Emily Heaton

Agronomy Publications

Much field research on perennial bioenergy crops confounds effects of plant age with those of the growing season, which increases uncertainty and the potential for erroneous conclusions, particularly in maturing stands. Most studies rely on stands planted in a single year and measured across multiple subsequent seasons. These “single-start” designs lack statistical power to separate temporal from environment effects.We used a staggered start experimental design to learn if increased statistical power clarified understanding of Miscanthus × giganteus nitrogen (N) needs. We conducted a staggered start experiment with three planting years and five N rates during the M. × giganteus yield-building phase ...


Physicochemical Organic Matter Stabilization Across A Restored Grassland Chronosequence, Shane M. Bugeja, Michael J. Castellano Dec 2018

Physicochemical Organic Matter Stabilization Across A Restored Grassland Chronosequence, Shane M. Bugeja, Michael J. Castellano

Agronomy Publications

In reconstructed grasslands, soil organic matter (SOM) is the largest CO2 and reactive N sink but SOM gains after reconstruction rarely achieve precultivation levels. Through a chronosequence of reconstructed grasslands 1 to 21 yr after establishment, we explored which physicochemical mechanisms protect accumulated soil organic C (SOC) and N from mineralization. After 21 yr, total SOC and soil N concentrations increased by 32 and 23%. The SOC concentration was within 5% of a new equilibrium but was 64% of a never‐cultivated remnant. Chemically stabilized C and N pools on free silt and clay surfaces increased with time. Coarse particulate ...


Agricultural Practices For Growing Kenaf (Hibiscus Cannabinus L.) In Iowa: I. Morphology, Stem, And Fiber Yield, Marie Bourguignon, Kenneth J. Moore, Andrew W. Lenssen, Brian S. Baldwin Dec 2018

Agricultural Practices For Growing Kenaf (Hibiscus Cannabinus L.) In Iowa: I. Morphology, Stem, And Fiber Yield, Marie Bourguignon, Kenneth J. Moore, Andrew W. Lenssen, Brian S. Baldwin

Agronomy Publications

Kenaf (Hibiscus cannabinus L.) is a promising biorenewable resource for producing natural fibers but few studies have investigated the crop when grown in cooler climates, such as the American Midwest. The objectives of this study were to: 1) determine the agricultural practices (row spacing, seed, and N rates) leading to optimal kenaf dry matter (DM) stem and fiber yield in ‘Tainung 2’ and ‘Whitten’; 2) evaluate stem height, basal diameter, and leaf area index (LAI) over the growing season; and 3) assess the influence of management practices on fiber (bast and core lignocellulose) composition, and carbon (C), N, and total ...


Assessing Variation In Maize Grain Nitrogen Concentration And Its Implications For Estimating Nitrogen Balance In The Us North Central Region, Fatima A. M. Tenorio, Alison J. Eagle, Eileen L. Mclellan, Kenneth G. Cassman, Reka Howard, Fred E. Below, David E. Clay, Jeffrey A. Coulter, Allen B. Geyer, Darin K. Joos, Joseph G. Lauer, Mark A. Licht, Alexander J. Lindsey, Bijesh Maharjan, Cameron M. Pittelkow, Peter R. Thomison, Charles S. Wortmann, Victor O. Sadras, Patricio Grassini Nov 2018

Assessing Variation In Maize Grain Nitrogen Concentration And Its Implications For Estimating Nitrogen Balance In The Us North Central Region, Fatima A. M. Tenorio, Alison J. Eagle, Eileen L. Mclellan, Kenneth G. Cassman, Reka Howard, Fred E. Below, David E. Clay, Jeffrey A. Coulter, Allen B. Geyer, Darin K. Joos, Joseph G. Lauer, Mark A. Licht, Alexander J. Lindsey, Bijesh Maharjan, Cameron M. Pittelkow, Peter R. Thomison, Charles S. Wortmann, Victor O. Sadras, Patricio Grassini

Agronomy Publications

Accurate estimation of nitrogen (N) balance (a measure of potential N losses) in producer fields requires information on grain N concentration (GNC) to estimate grain-N removal, which is rarely measured by producers. The objectives of this study were to (i) examine the degree to which variation in GNC can affect estimation of grain-N removal, (ii) identify major factors influencing GNC, and (iii) develop a predictive model to estimate GNC, analyzing the uncertainty in predicted grain-N removal at field and regional levels. We compiled GNC data from published literature and unpublished databases using explicit criteria to only include experiments that portray ...


Perennial Biomass Crop Establishment, Community Characteristics, And Productivity In The Upper Us Midwest: Effects Of Cropping Systems Seed Mixtures And Biochar Applications, Catherine L. Bonin, Rivka B. Fidel, Chumki Banik, David A. Laird, Robert Mitchell, Emily A. Heaton Nov 2018

Perennial Biomass Crop Establishment, Community Characteristics, And Productivity In The Upper Us Midwest: Effects Of Cropping Systems Seed Mixtures And Biochar Applications, Catherine L. Bonin, Rivka B. Fidel, Chumki Banik, David A. Laird, Robert Mitchell, Emily A. Heaton

Agronomy Publications

Native perennial plants have potential as bioenergy feedstocks, but their use is currently limited by relatively long establishment times and low biomass yields. Some research suggests that incorporating plant species diversity and applying biochar as a soil amendment might alleviate these limitations by creating a more resilient crop and soil system. The objective of this research was to investigate how 1) seeded plant diversity and 2) biochar soil amendments interact to affect the establishment, yield, and plant species composition of biomass cropping systems during the first four years of growth on productive soils. We measured species emergence, cover, peak and ...


Legacy Effects Of Long-Term Nitrogen Fertilizer Application On The Fate Of Nitrogen Fertilizer Inputs In Continuous Maize, Hanna J. Poffenbarger, John E. Sawyer, Daniel W. Barker, Daniel C. Olk, Johan Six, Michael J. Castellano Oct 2018

Legacy Effects Of Long-Term Nitrogen Fertilizer Application On The Fate Of Nitrogen Fertilizer Inputs In Continuous Maize, Hanna J. Poffenbarger, John E. Sawyer, Daniel W. Barker, Daniel C. Olk, Johan Six, Michael J. Castellano

Agronomy Publications

Nitrogen fertilizer management can impact soil organic C (SOC) stocks in cereal-based cropping systems by regulating crop residue inputs and decomposition rates. However, the impact of long-term N fertilizer management, and associated changes in SOC quantity and quality, on the fate of N fertilizer inputs is uncertain. Using two 15-year N fertilizer rate experiments on continuous maize (Zea mays L.) in Iowa, which have generated gradients of SOC, we evaluated the legacy effects of N fertilizer inputs on the fate of added N. Across the historical N fertilizer rates, which ranged from 0 to 269 kg N ha−1 yr ...