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2019

Agriculture

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Full-Text Articles in Life Sciences

Canavalia And Dolichos Extracts For Sustainable Pest Biocontrol And Plant Nutrition Improvement In El Salvador, Carlos Martinez Oct 2019

Canavalia And Dolichos Extracts For Sustainable Pest Biocontrol And Plant Nutrition Improvement In El Salvador, Carlos Martinez

Theses, Dissertations, and Student Research in Agronomy and Horticulture

Botanical repellents and pesticides are now being rediscovered as new tools for integrated pest management in order to reduce the use of toxic chemicals in crop production. Canavalia gladiata and Dolichos lablab are two Fabaceae very well adapted to farmlands of El Salvador, effective as living barriers and mostly as cover crops, however, they are not yet very well disseminated. This document describes the potential for using the liquid extracts and the dry flour of raw seeds of those plants for economic benefit and practical convenience for pest management in Salvadorian agriculture under field conditions. Seed extracts were useful when ...


Fall Frost Tolerances Photo Fact Sheet (2019), Carolyn J. Demoranville Oct 2019

Fall Frost Tolerances Photo Fact Sheet (2019), Carolyn J. Demoranville

Cranberry Station Fact Sheets

No abstract provided.


Barriers, Roles, And Information Source Preferences For Utilizing Agricultural Science Projects Among Utah 4-H Extension Professionals, Aleigh Aurin Aug 2019

Barriers, Roles, And Information Source Preferences For Utilizing Agricultural Science Projects Among Utah 4-H Extension Professionals, Aleigh Aurin

All Graduate Theses and Dissertations

Agriscience is the growing study of biotechnology, business, and economics within the agriculture industry. Through 4-H, youth can experience hands on learning through different program areas. The purpose of this study was to identify the barriers, roles, and how Utah 4-H personnel preferred to learn about new programs. The study showed time and available volunteers were a barrier for 4-H Extension personnel to implement Agriscience projects. Other results included internet and workshops as the top choices for training programs. The Extension personnel agreed it was their job to involve and educate youth. Yet, need training in how to integrate Robotics ...


Twenty-First Century Skills: A Needs Assessment Of School-Based Agricultural Education Teachers, Kisia J. Weeks Aug 2019

Twenty-First Century Skills: A Needs Assessment Of School-Based Agricultural Education Teachers, Kisia J. Weeks

All Graduate Theses and Dissertations

Preparing students to be career and work ready is a concern of educators and schools nationwide. Twenty-first century skills prepare students to enter the workforce or higher education with the ability to think critically and creatively, collaborate with others, take the initiative when approached with a task, and use technology to its fullest potential. If students are not learning the skills needed for success, it is because educators and schools are not teaching them. When students possess these skills, they are prepared to work in teams, think critically and creatively about a problem, display leadership and social skills, and communicate ...


Evaluating Machine Learning Performance In Predicting Injury Severity In Agribusiness Industries, Fatemeh Davoudi Kakhki, Steven A. Freeman, Gretchen A. Mosher Aug 2019

Evaluating Machine Learning Performance In Predicting Injury Severity In Agribusiness Industries, Fatemeh Davoudi Kakhki, Steven A. Freeman, Gretchen A. Mosher

Agricultural and Biosystems Engineering Publications

Although machine learning methods have been used as an outcome prediction tool in many fields, their utilization in predicting incident outcome in occupational safety is relatively new. This study tests the performance of machine learning techniques in modeling and predicting occupational incidents severity with respect to accessible information of injured workers in agribusiness industries using workers’ compensation claims. More than 33,000 incidents within agribusiness industries in the Midwest of the United States for 2008–2016 were analyzed. The total cost of incidents was extracted and classified from workers’ compensation claims. Supervised machine learning algorithms for classification (support vector machines ...


Measuring Sub-Second Wind Velocity Changes For Agricultural Drift One Meter Above The Ground, Matthew W. Schramm, H. Mark Hanna, Matthew J. Darr, Steven J. Hoff, Brian L. Steward Jul 2019

Measuring Sub-Second Wind Velocity Changes For Agricultural Drift One Meter Above The Ground, Matthew W. Schramm, H. Mark Hanna, Matthew J. Darr, Steven J. Hoff, Brian L. Steward

Brian L. Steward

Agricultural spray drift is affected by many factors including current weather conditions, topography of the surrounding area, fluid properties at the nozzle, and the height at which the spray is released. During the late spring/summer spray seasons of 2014 and 2015, wind direction, speed, and solar radiation (2014 only) were measured at 10 Hz, one meter above the ground to investigate conditions that are typically encountered by a droplet when released from a nozzle on an agricultural sprayer. Measurements of wind velocity as the wind passed from an upwind sensor to a downwind sensor were used to evaluate what ...


Tillage In 2001: Fall Strip-Tillage, Mahdi Al-Kaisi, H. Mark Hanna, Michael J. Tidman Jul 2019

Tillage In 2001: Fall Strip-Tillage, Mahdi Al-Kaisi, H. Mark Hanna, Michael J. Tidman

H. Mark Hanna

Every tillage practice has distinct advantages and disadvantages, requires specific equipment, and requires that you learn how to successfully implement the practice in your operation. In this article, we discuss the merits of fall strip-tillage and present some of the facts you need to consider to implement fall strip-tillage.


Tillage Implement Design And Its Effect On Soil, Mahdi Al-Kaisi, H. Mark Hanna, Michael Tidman Jul 2019

Tillage Implement Design And Its Effect On Soil, Mahdi Al-Kaisi, H. Mark Hanna, Michael Tidman

H. Mark Hanna

The weather is gradually improving and most Iowa producers are getting closer to working in the field. Some have already started fieldwork. However, there is still time to finalize preparation of tillage implements for spring fieldwork. Producers are encouraged to check and evaluate the design of soil-engaging components of their tillage implements, assess the potential for soil erosion, and think about their chances for a successful crop.


Tillage Equipment Maintenance, H. Mark Hanna, Mahdi Al-Kaisi, Michael J. Tidman Jul 2019

Tillage Equipment Maintenance, H. Mark Hanna, Mahdi Al-Kaisi, Michael J. Tidman

H. Mark Hanna

Many crop operations experience a lull in mid-winter. This lull is a great time to take a look at tillage equipment maintenance for the 2002 growing season and catch up on "little fixes" that were put off from last year. Proper setup and maintenance of tillage equipment can eliminate extra tillage trips through the field and increase equipment efficiency, which preserves crop residue and limits soil erosion.


Barriers And Motivators For Tractors Rops Retrofitting In Iowa, Charles V. Schwab, J. Gordon Arbuckle, H. Mark Hanna Jul 2019

Barriers And Motivators For Tractors Rops Retrofitting In Iowa, Charles V. Schwab, J. Gordon Arbuckle, H. Mark Hanna

H. Mark Hanna

Iowa State University Extension and Outreach conducted an assessment of Iowa farm operators’ perceptions about the barriers and motivators when considering retrofitting tractors with rollover protective structures (ROPS). A statewide sample of approximately 2,000 farm operators were surveyed in the 2017 Iowa Farm and Rural Life Poll. A series of questions were asked to evaluate the importance of potential barriers to decisions not to retrofit a tractor and potential motivators that could influence the decision to retrofit or purchase a tractor with ROPS. The survey received a 48% response rate with 999 responses. Among the 76% of Iowa farm ...


Measuring Sub-Second Wind Velocity Changes For Agricultural Drift One Meter Above The Ground, Matthew W. Schramm, H. Mark Hanna, Matthew J. Darr, Steven J. Hoff, Brian L. Steward Jul 2019

Measuring Sub-Second Wind Velocity Changes For Agricultural Drift One Meter Above The Ground, Matthew W. Schramm, H. Mark Hanna, Matthew J. Darr, Steven J. Hoff, Brian L. Steward

H. Mark Hanna

Agricultural spray drift is affected by many factors including current weather conditions, topography of the surrounding area, fluid properties at the nozzle, and the height at which the spray is released. During the late spring/summer spray seasons of 2014 and 2015, wind direction, speed, and solar radiation (2014 only) were measured at 10 Hz, one meter above the ground to investigate conditions that are typically encountered by a droplet when released from a nozzle on an agricultural sprayer. Measurements of wind velocity as the wind passed from an upwind sensor to a downwind sensor were used to evaluate what ...


Measuring Sub-Second Wind Velocity Changes For Agricultural Drift One Meter Above The Ground, Matthew W. Schramm, H. Mark Hanna, Matthew J. Darr, Steven J. Hoff, Brian L. Steward Jul 2019

Measuring Sub-Second Wind Velocity Changes For Agricultural Drift One Meter Above The Ground, Matthew W. Schramm, H. Mark Hanna, Matthew J. Darr, Steven J. Hoff, Brian L. Steward

Matthew J. Darr

Agricultural spray drift is affected by many factors including current weather conditions, topography of the surrounding area, fluid properties at the nozzle, and the height at which the spray is released. During the late spring/summer spray seasons of 2014 and 2015, wind direction, speed, and solar radiation (2014 only) were measured at 10 Hz, one meter above the ground to investigate conditions that are typically encountered by a droplet when released from a nozzle on an agricultural sprayer. Measurements of wind velocity as the wind passed from an upwind sensor to a downwind sensor were used to evaluate what ...


Measuring Sub-Second Wind Velocity Changes For Agricultural Drift One Meter Above The Ground, Matthew W. Schramm, H. Mark Hanna, Matthew J. Darr, Steven J. Hoff, Brian L. Steward Jul 2019

Measuring Sub-Second Wind Velocity Changes For Agricultural Drift One Meter Above The Ground, Matthew W. Schramm, H. Mark Hanna, Matthew J. Darr, Steven J. Hoff, Brian L. Steward

Steven J. Hoff

Agricultural spray drift is affected by many factors including current weather conditions, topography of the surrounding area, fluid properties at the nozzle, and the height at which the spray is released. During the late spring/summer spray seasons of 2014 and 2015, wind direction, speed, and solar radiation (2014 only) were measured at 10 Hz, one meter above the ground to investigate conditions that are typically encountered by a droplet when released from a nozzle on an agricultural sprayer. Measurements of wind velocity as the wind passed from an upwind sensor to a downwind sensor were used to evaluate what ...


Effects Of Cage Stocking Density On Feeding Behaviors Of Group-Housed Laying Hens, Rachel Nichole Cook, Hongwei Xin, Dan Nettleton Jul 2019

Effects Of Cage Stocking Density On Feeding Behaviors Of Group-Housed Laying Hens, Rachel Nichole Cook, Hongwei Xin, Dan Nettleton

Dan Nettleton

Quantitative measurement of animal welfare continues to be a challenging task for both the animal agriculture industry and the scientific community. Characterization of animal feeding behavior provides a comparative elucidation of the animal’s behavioral deviation from its norms and thus carries implications for its welfare. This study examines the effects of cage stocking density (348, 387, 426, and 465 cm2; or 54, 60, 66, and 72 in.2 cage floor space per hen) on feeding behavior of W-36 White Leghorn laying hens kept in groups of six hens. The study employed a specialized instrumentation system and computational algorithm. The ...


Feeding Behaviors Of Laying Hens With Or Without Beak Trimming, Kelly E. Persyn, Hongwei Xin, Dan Nettleton, Atsuo Ikeguchi, Richard S. Gates Jul 2019

Feeding Behaviors Of Laying Hens With Or Without Beak Trimming, Kelly E. Persyn, Hongwei Xin, Dan Nettleton, Atsuo Ikeguchi, Richard S. Gates

Dan Nettleton

This study quantifies feeding behavior of W-36 White Leghorn laying hens (77 to 80 weeks old) as influenced by the management practice of beak trimming. The feeding behavior was characterized using a newly developed measurement system and computational algorithm. Non-trimmed (NT) and beak-trimmed (BT) hens showed similar daily feed intake and meal size. However, the BT hens tended to spend longer time feeding (3.3 vs. 2.0 h/d, P < 0.01), which coincided with their slower ingestion rate of 0.43 g/min-kg0.75 vs. 0.79 g/min-kg0.75 for the NT counterparts (P < 0.05). The BT hens had shorter time intervals between meals (101 s vs. 151 s, P < 0.01). Selective feeding, as demonstrated by larger feed particles apparent in the leftover feed, was noted for the BT hens. The leftover feed had a lower crude protein/adjusted crude protein content for the BT birds than that for the NT birds (16.7% vs. 18.7%, P < 0.05). In addition, the leftover feed of the BT birds had lower contents in phosphorus, magnesium, potassium, zinc, and manganese (P < 0.05), although no significant differences were detected in calcium, sodium, or metabolic energy content. Baseline feeding behavior data of this nature may help quantify and ensure the welfare of animals through exercising proper engineering design and/or management considerations.


Stability Of Single-Parent Gene Expression Complementation In Maize Hybrids Upon Water Deficit Stress, Caroline Marcon, Anja Paschold, Waqas Ahmed Malik, Andrew Lithio, Jutta A. Baldauf, Lena Altrogge, Nina Opitz, Christa Lanz, Heiko Schoof, Dan Nettleton, Hans-Peter Piepho, Frank Hochholdinger Jul 2019

Stability Of Single-Parent Gene Expression Complementation In Maize Hybrids Upon Water Deficit Stress, Caroline Marcon, Anja Paschold, Waqas Ahmed Malik, Andrew Lithio, Jutta A. Baldauf, Lena Altrogge, Nina Opitz, Christa Lanz, Heiko Schoof, Dan Nettleton, Hans-Peter Piepho, Frank Hochholdinger

Dan Nettleton

Heterosis is the superior performance of F1 hybrids compared with their homozygous, genetically distinct parents. In this study, we monitored the transcriptomic divergence of the maize (Zea mays) inbred lines B73 and Mo17 and their reciprocal F1 hybrid progeny in primary roots under control and water deficit conditions simulated by polyethylene glycol treatment. Single-parent expression (SPE) of genes is an extreme instance of gene expression complementation, in which genes are active in only one of two parents but are expressed in both reciprocal hybrids. In this study, 1,997 genes only expressed in B73 and 2,024 genes only expressed ...


Co-Expression Networks Reveal Potential Regulatory Roles Of Mirnas In Fatty Acid Composition Of Nelore Cattle, Priscila S. N. De Oliveira, Luiz L. Coutinho, Aline S. M. Cesar, Wellison J. Da Silva Diniz, Marcela M. De Souza, Bruno G. Andrade, James E. Koltes, Gerson B. Mourão, Adhemar Zerlotini, James M. Reecy, Luciana C. A. Regitano Jul 2019

Co-Expression Networks Reveal Potential Regulatory Roles Of Mirnas In Fatty Acid Composition Of Nelore Cattle, Priscila S. N. De Oliveira, Luiz L. Coutinho, Aline S. M. Cesar, Wellison J. Da Silva Diniz, Marcela M. De Souza, Bruno G. Andrade, James E. Koltes, Gerson B. Mourão, Adhemar Zerlotini, James M. Reecy, Luciana C. A. Regitano

Animal Science Publications

Fatty acid (FA) content affects the sensorial and nutritional value of meat and plays a significant role in biological processes such as adipogenesis and immune response. It is well known that, in beef, the main FAs associated with these biological processes are oleic acid (C18:1 cis9, OA) and conjugated linoleic acid (CLA-c9t11), which may have beneficial effects on metabolic diseases such as type 2 diabetes and obesity. Here, we performed differential expression and co-expression analyses, weighted gene co-expression network analysis (WGCNA) and partial correlation with information theory (PCIT), to uncover the complex interactions between miRNAs and mRNAs expressed in ...


Thermal Property Values Of A Central Iowa Soil As Functions Of Soil Water Content And Bulk Density Or Of Soil Air Content, Bing Tong, Dilia Kool, Joshua L. Heitman, Thomas J. Sauer, Zhiqiu Gao, Robert Horton Jul 2019

Thermal Property Values Of A Central Iowa Soil As Functions Of Soil Water Content And Bulk Density Or Of Soil Air Content, Bing Tong, Dilia Kool, Joshua L. Heitman, Thomas J. Sauer, Zhiqiu Gao, Robert Horton

Robert Horton

Soil thermal properties play important roles in dynamic heat and mass transfer processes, and they vary with soil water content (θ) and bulk density (ρ b). Both θ and ρ bchange with time, particularly in recently tilled soil. However, few studies have addressed the full extent of soil thermal property changes with θ and ρ b. The objective of this study is to examine how changes in ρ b with time after tillage impact soil thermal properties (volumetric heat capacity, C v, thermal diffusivity, k, and thermal conductivity, λ). The study provides thermal property values as functions of θ ...


Preservice Teacher Perceptions Of The Role Of An Agriculture Teacher During Their Early Field Experience, Scott Smalley, Bryan D. Rank Jul 2019

Preservice Teacher Perceptions Of The Role Of An Agriculture Teacher During Their Early Field Experience, Scott Smalley, Bryan D. Rank

Scott Smalley

School-based agriculture teachers (SBAE) hold many roles inside and outside of the school. Identifying and understanding the many roles an agriculture teacher may have in their career is an important part of an early field experience (EFE). In this study, EFE students (n = 18) submitted written reflections focused on the role of an agriculture teacher. Open coding of the preservice teacher reflections revealed five themes including work-life balance, public relations, role of an FFA advisor, student success, and school responsibilities. Codes within these five themes indicate a student-centered approach among agriculture teachers. Additionally, EFE students described many school responsibilities outside ...


School-Based Agricultural Education Teachers’ Perceived Professional Development Needs Associated With Teaching, Classroom Management, And Technical Agriculture, Scott Smalley, Mark S. Hainline, Kelsey Sands Jul 2019

School-Based Agricultural Education Teachers’ Perceived Professional Development Needs Associated With Teaching, Classroom Management, And Technical Agriculture, Scott Smalley, Mark S. Hainline, Kelsey Sands

Scott Smalley

Across the nation, there is a large shortage of teachers in several subject areas (Daniel, 2015; Milliard, 2015; Sutcher, Darling-Hammond, & Carver-Thomas, 2016). In agricultural education, many teachers are leaving the profession within the first five years of beginning their teaching careers (Tippens, Ricketts, Morgan, Navaro, & Flanders, 2013). Professional development opportunities for teachers can be utilized to retain teachers in the profession (Touchstone, 2015). The purpose of this study was to evaluate the professional development needs of Iowa school-based agricultural education teachers in the areas of teaching, classroom management, and technical agriculture. Motivating students to learn, teaching in a land laboratory ...


Understanding Anhydrous Ammonia Application In Soil, John E. Sawyer Jul 2019

Understanding Anhydrous Ammonia Application In Soil, John E. Sawyer

John E. Sawyer

What happens when anhydrous ammonia is injected into soil?

Several physical and chemical reactions take place following anhydrous ammonia injection: dissolution in water, reaction with soil organic matter and clay, and attachment of ammonium ions on the soil cation exchange complex. These reactions all tend to limit the movement of ammonia, with water having the greatest initial effect. The highest concentration of ammonia is at/near the point of injection, with a tapering of the concentration toward the outer edge of the retention zone. Usually the greatest ammonia concentration is within the first inch or two of the injection point ...


Flood Adulterated Grain - Nutrient Supply To Crops When Land Applied, John E. Sawyer, Antonio Mallarino Jul 2019

Flood Adulterated Grain - Nutrient Supply To Crops When Land Applied, John E. Sawyer, Antonio Mallarino

John E. Sawyer

Flooding has been extensive in several areas of Iowa this spring. In some cases, stored grain has been affected by flood waters. Land application of flood adulterated grain as a nutrient source for a future crop may be an option for some. See the Iowa Dept. of Natural Resources (IDNR) and Iowa Dept. of Agriculture and Land Stewardship (IDALS) publication for Proper Management of Flooded Grain and Hay. That publication states “Farms disposing of spoiled grain and feed on their own property can land apply damaged grain at the following application rates: 146 bu corn/acre and 50 bu soybean ...


Anhydrous Ammonia Application -- Spring 2019, John E. Sawyer Jul 2019

Anhydrous Ammonia Application -- Spring 2019, John E. Sawyer

John E. Sawyer

It was a late harvest in fall 2018. Soils were wet and frozen when it was time to apply anhydrous ammonia. Those situations resulted in much less than normal anhydrous ammonia application last fall. Therefore, considerable anhydrous ammonia needs to be applied this spring. There is only so much capacity to switch from one nitrogen (N) fertilizer product to another. In Iowa, historically the two largest N fertilizers are anhydrous ammonia (largest) and urea-ammonium nitrate (UAN) solution, with granulated urea a distant third.


Springtime Precipitation – A Tool For Estimating Nitrogen Application Need For Corn, John E. Sawyer Jul 2019

Springtime Precipitation – A Tool For Estimating Nitrogen Application Need For Corn, John E. Sawyer

John E. Sawyer

Wet springtime conditions typically raise questions about the status of applied nitrogen (N). Or the question, do I need to apply additional N to my cornfields? At this time we do not know what the weather/precipitation will be for the entire springtime, but the extended period of wet conditions this spring is of concern. A summary of long-term N rate trials with continuous corn and corn rotated with soybean conducted at seven ISU research and demonstration farms in Iowa from 1999 to 2016 has been an on-going basis for indicating the potential for needing an N rate greater than ...


Nitrogen Fertilization Options With Delayed Or Rescue Applications, John E. Sawyer Jul 2019

Nitrogen Fertilization Options With Delayed Or Rescue Applications, John E. Sawyer

John E. Sawyer

It’s been a wait-go-stop (repeat) corn planting season this spring. Whether you planted early or are just now getting corn planted, it seems planting windows were short and rushed. In some cases this meant planting (corn/soybean) and worrying later about getting nitrogen (N) applied. And in some areas of Iowa, wetter than normal conditions are raising questions about supplemental N application. What are the options for sidedress N?


Effects Of Unharvested, Shattered, Or Hailed-Out Soybean Fields On Nutrient Supply For Corn, John E. Sawyer Jul 2019

Effects Of Unharvested, Shattered, Or Hailed-Out Soybean Fields On Nutrient Supply For Corn, John E. Sawyer

John E. Sawyer

Flooded fields and wet soil conditions in the fall 2018 meant some soybean fields were not, or are not going to be harvested. Also, some fields occasionally experienced significant shattering or a hailstorm in the fall where soybean seed is knocked from the plants and thus not harvested. When the grain is not harvested, nitrogen (N), phosphorus (P), and potassium (K) nutrients returned to the soil in the soybean grain can be accounted for when planning nutrient applications for the next crop. Other nutrients will also be returned, but most are not a fertilization need in Iowa soils. An estimate ...


First-Order Estimates Of The Costs, Input-Output Energy Analysis, And Energy Returns On Investment Of Conventional And Emerging Biofuels Feedstocks, Katrina Christiansen, D. Raj Raman, Guiping Hu, Robert Anex Jul 2019

First-Order Estimates Of The Costs, Input-Output Energy Analysis, And Energy Returns On Investment Of Conventional And Emerging Biofuels Feedstocks, Katrina Christiansen, D. Raj Raman, Guiping Hu, Robert Anex

Guiping Hu

Here we report on a static, algebraic, spreadsheet-implemented modeling approach to estimate the costs, energy inputs and outputs, and global warming potential of biomass feedstocks. Inputs to the model included literature sourced data for: environmental factors, crop physiological-parameters such as radiation use efficiency and water use efficiency, and crop cost components. Using an energy-input-output life-cycle-assessment approach, we calculated the energy associated with each cost component, allowing an estimate of the total energy required to produce the crop and fuel alongside the energy return on investment. We did this for crop scenarios in the upper Midwest US and Far West US ...


Healthy Food As A New Technology—The Implications Of Technological Diffusion And Food Price For Changes In Eating Habits, Anne E. Dohmen, D. Raj Raman Jul 2019

Healthy Food As A New Technology—The Implications Of Technological Diffusion And Food Price For Changes In Eating Habits, Anne E. Dohmen, D. Raj Raman

D. Raj Raman

Diet influences health and poor diets drive up healthcare costs for individuals and society as a whole. Multiple governmental programs in the US have aimed to educate citizens about diet choices, resulting in documented successes, as well as, unintended consequences such as increased food waste. Here we examine some of the relationships between healthy diets, food prices, and wealth by drawing parallels between the diffusion of technological innovation and healthy food diets. We introduce a simple modeling framework to estimate the adoption rates of healthy diets based on income and food prices, and describe the implications of the modeling results ...


First-Order Estimates Of The Costs, Input-Output Energy Analysis, And Energy Returns On Investment Of Conventional And Emerging Biofuels Feedstocks, Katrina Christiansen, D. Raj Raman, Guiping Hu, Robert Anex Jul 2019

First-Order Estimates Of The Costs, Input-Output Energy Analysis, And Energy Returns On Investment Of Conventional And Emerging Biofuels Feedstocks, Katrina Christiansen, D. Raj Raman, Guiping Hu, Robert Anex

D. Raj Raman

Here we report on a static, algebraic, spreadsheet-implemented modeling approach to estimate the costs, energy inputs and outputs, and global warming potential of biomass feedstocks. Inputs to the model included literature sourced data for: environmental factors, crop physiological-parameters such as radiation use efficiency and water use efficiency, and crop cost components. Using an energy-input-output life-cycle-assessment approach, we calculated the energy associated with each cost component, allowing an estimate of the total energy required to produce the crop and fuel alongside the energy return on investment. We did this for crop scenarios in the upper Midwest US and Far West US ...


Use Of Legume Green Manures As Nitrogen Sources For Corn Production, Matt Liebman, Rhonda L. Graef, Daniel Nettleton, Cynthia A. Cambardella Jul 2019

Use Of Legume Green Manures As Nitrogen Sources For Corn Production, Matt Liebman, Rhonda L. Graef, Daniel Nettleton, Cynthia A. Cambardella

Dan Nettleton

Recent volatility in supplies and prices of natural gas and synthetic nitrogen (N) fertilizer suggests a need to develop and refine alternative strategies for supplying N to corn. In this study, conducted in north-eastern Iowa, we examined the use of red clover and alfalfa green manures as means of supplying N to a succeeding corn crop. Red clover intercropped with oat produced significantly more biomass and contained more N than alfalfa intercropped with oat. Tilling green manures in the fall or delaying tillage until the following spring did not have a consistent effect on green manure N content. Without N ...