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What Is Meant By Crop Availability Of Manure Nutrients?, John Sawyer, Antonio P. Mallarino 2017 Iowa State University

What Is Meant By Crop Availability Of Manure Nutrients?, John Sawyer, Antonio P. Mallarino

John E. Sawyer

Nutrient management guidelines in Iowa and other states use the words “manure nutrient availability” when suggesting manure application rates to supply nutrients needed by crops. People are sometimes confused about the meaning of the word “availability.” In fact, manure management guidelines across the region vary in the exact use and this contributes to confusion. Interestingly, Webster’s Ninth New Collegiate Dictionary includes “plant” and “nitrogen” in the definition of “available.” One definition is “present or ready for immediate use”, and another definition is “present in such chemical or physical form as to be usable (as by a plant) <~ nitrogen> …” So, why ...


Sensing Nitrogen Stress In Corn, John Sawyer, John Lundvall, Jennifer Hawkins, Dan Barker 2017 Iowa State University

Sensing Nitrogen Stress In Corn, John Sawyer, John Lundvall, Jennifer Hawkins, Dan Barker

John E. Sawyer

Determining the proper nitrogen (N) fertilization rate is important for the economic viability of corn production. A desire for high yields, fueled by low fertilizer N costs, led producers to apply rates that ensured adequate N rather than risk costly yield losses due to a shortage of N. Due to water quality concerns and recently high N fertilizer prices, management strategies are needed that can improve the efficiency and profitability of N use. With N application rates based on economic return instead of maximizing productivity, producers want to confirm that rate decisions are working adequately. Also, if unexpected N losses ...


Manure Resources, Jeffery Lorimor, Antonio Mallarino, John Sawyer, John Creswell 2017 Iowa State University

Manure Resources, Jeffery Lorimor, Antonio Mallarino, John Sawyer, John Creswell

John E. Sawyer

Using manure as a resource.


Nitrogen Application, John Sawyer, John Creswall 2017 Iowa State University

Nitrogen Application, John Sawyer, John Creswall

John E. Sawyer

Nitrogen (N) management planning for corn production.


Nutrient Management Plan, Antonio Mallarino, John Sawyer, Barbara Stewart, John Creswell 2017 Iowa State University

Nutrient Management Plan, Antonio Mallarino, John Sawyer, Barbara Stewart, John Creswell

John E. Sawyer

Management tools to help you develop a nutrient management plan and use the Iowa Phosphorus Index.


Crop Rotation, Jerald DeWitt, Michael Duffy, Gerald Miller, John Sawyer, John Creswell 2017 Iowa State University

Crop Rotation, Jerald Dewitt, Michael Duffy, Gerald Miller, John Sawyer, John Creswell

John E. Sawyer

Understanding the potential benefits of a crop rotation system.


Soil Testing, Antonio Mallarino, John Sawyer, John Creswell 2017 Iowa State University

Soil Testing, Antonio Mallarino, John Sawyer, John Creswell

John E. Sawyer

Establishing and using a soil testing program to more efficiently manage crop essential nutrients.


Phosphorus Application, Antonio Mallarino, John Sawyer, John Creswell 2017 Iowa State University

Phosphorus Application, Antonio Mallarino, John Sawyer, John Creswell

John E. Sawyer

Management tools that help in creating a phosphorus management plan.


Precision Drought Stress In Orchards: Rootstock Evaluation, Trunk Hydration And Canopy Temperature, Lance V. Scott 2017 Utah State University

Precision Drought Stress In Orchards: Rootstock Evaluation, Trunk Hydration And Canopy Temperature, Lance V. Scott

All Graduate Theses and Dissertations

In many areas, over half of all diverted water is used for irrigation. Tree fruit crops use a lot of water, but water productivity can be increased using properly-timed precision water stress. In addition to water conservation, increases in water productivity arise from better fruit quality, increased storage life and reductions in pruning and maintenance. One major hurdle to applying precision water stress in orchards is the lack of a reliable, automated method of determining tree water status. However, the influence of physiological characteristics such as rootstock vigor on water productivity are also important. Selecting the most appropriate rootstocks and ...


How To Interpret Your Manure Analysis, Angela Rieck-Hinz, Thomas G. Miller, John E. Sawyer 2017 Iowa State University

How To Interpret Your Manure Analysis, Angela Rieck-Hinz, Thomas G. Miller, John E. Sawyer

John E. Sawyer

Manure analysis is a critical component of proper nutrient management planning. Table or book values of manure nutrient concentrations can serve as a starting point for planning purposes, but actual manure sample analysis provides a better indication of manure nutrient concentrations and will help better define application rates. Utilizing manure testing will help achieve the potential as a crop nutrient source, and result in reduced chance for misapplication that could lead to lower crop productivity or increased environmental risk.


Winter Rye Cover Crop Biomass Production, Degradation, And Nitrogen Recycling, Jose L. Pantoja, Krishna P. Woli, John E. Sawyer, Daniel W. Barker 2017 Universidad de las Fuerzas Armadas

Winter Rye Cover Crop Biomass Production, Degradation, And Nitrogen Recycling, Jose L. Pantoja, Krishna P. Woli, John E. Sawyer, Daniel W. Barker

John E. Sawyer

Winter rye (Secale cereale L.) cover crop (RCC) use in corn (Zea mays L.) and soybean [Glycine max. (L.) Merr.] production can alter N dynamics compared to no RCC. The objectives of this study were to evaluate RCC biomass production (BP) and subsequent RCC degradation (BD) and N recycling in a no-till corn–soybean (CS) rotation. Aboveground RCC was sampled at spring termination for biomass dry matter (DM), C, and N. To evaluate BD and remaining C and N, RCC biomass was put into nylon mesh bags, placed on the soil surface, and collected multiple times over 105 d. Treatments ...


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 2017 Iowa State University

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 ...


Nutrient Deficiencies And Application Injuries In Field Crops, John E. Sawyer 2017 Iowa State University

Nutrient Deficiencies And Application Injuries In Field Crops, John E. Sawyer

John E. Sawyer

No abstract provided.


Take A Good Soil Sample To Help Make Good Decisions, John Sawyer, Antonio Mallarino, Randy Killorn 2017 Iowa State University

Take A Good Soil Sample To Help Make Good Decisions, John Sawyer, Antonio Mallarino, Randy Killorn

John E. Sawyer

One of the most important steps in soil testing is collecting the soil sample. The soil sample is the fi rst part of the soil testing process and the foundation for information derived from laboratory analyses, soil test interpretations, and recommendations. Also, soil sampling is the largest source of errors in the soil testing process.

Remember why you are taking soil samples -- to obtain information on which you can base recommendations and decisions concerning fertilizer, manure, and limestone use.

A comprehensive soil fertility and organic matter map for each fi eld is desirable as a basis on which to adjust ...


Corn Nitrogen Fertilization Requirement And Corn–Soybean Productivity With A Rye Cover Crop, Jose L. Pantoja, Krishna P. Woli, John E. Sawyer, Daniel W. Barker 2017 Universidad de las Fuerzas Armadas Pichincha

Corn Nitrogen Fertilization Requirement And Corn–Soybean Productivity With A Rye Cover Crop, Jose L. Pantoja, Krishna P. Woli, John E. Sawyer, Daniel W. Barker

John E. Sawyer

Winter rye (Secale cereale L.) cover crop (RCC) has potential to reduce NO3–N loss from corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] fields. However, RCC effects on annual crop productivity and corn optimal N fertilization requirement are unclear. The objectives were to evaluate corn and soybean yield response to RCC and corn optimal N rate. Treatments were no-RCC and RCC with six fertilizer N rates (0–225 kg N ha-1) applied to corn in a no-till corn–soybean (CS) rotation at four Iowa sites in 2009 through 2011. The RCC biomass and N uptake was low ...


Agronomic Comparison Of Anhydrous Ammonia Applied With A High Speed-Low Draft Opener And Conventional Knife Injection In Corn, Krishna P. Woli, Fabián G. Fernández, John E. Sawyer, Joshua D. Stamper, David B. Mengel, Daniel W.. Barker, Mark H. Hanna 2017 Iowa State University

Agronomic Comparison Of Anhydrous Ammonia Applied With A High Speed-Low Draft Opener And Conventional Knife Injection In Corn, Krishna P. Woli, Fabián G. Fernández, John E. Sawyer, Joshua D. Stamper, David B. Mengel, Daniel W.. Barker, Mark H. Hanna

John E. Sawyer

Anhydrous ammonia (AA) is an important N fertilizer in the U.S., and with large farming operations rapid application is needed. This study evaluated the impact of AA application timing and N rates when applied with a high speed low draft (HSLD) or a conventional till knife (CTKI) on corn (Zea Mays L.) production in no-tillage fields. The study was conducted at sites located in Illinois, Iowa, and Kansas from 2007 to 2009. The experimental design was a split-plot factorial arrangement of application method, timing (fall; spring preplant, SP; and sidedress, SD), and five N rates. Fall AA application was ...


Phosphorus Indexing For Cropland: Overview And Basic Concepts Of The Iowa Phosphorus Index, A. P. Mallarino, B. M. Stewart, J. L. Baker, J. D. Downing, J. E. Sawyer 2017 Iowa State University

Phosphorus Indexing For Cropland: Overview And Basic Concepts Of The Iowa Phosphorus Index, A. P. Mallarino, B. M. Stewart, J. L. Baker, J. D. Downing, J. E. Sawyer

John E. Sawyer

Excessive phosphorus (P) loss from soils impairs surface water resources. An assessment tool or index has been proposed to identify fields with high potential risk of P delivery. The P index integrates P source and transport factors into a decision making process that may lead to changes in current P management and soil conservation practices. The index recognizes that a single soil P threshold alone is not an appropriate evaluation factor because of the varying conditions across fields. Although most indices being developed in the United States include similar factors, source and transport characteristics are considered in various ways to ...


Does Nitrogen Fertilizer Application Rate To Corn Affect Nitrous Oxide Emissions From The Rotated Soybean Crop?, Javed Iqbal, David C. Mitchell, Daniel W. Barker, Fernando Miguez, John E. Sawyer, Jose Pantoja, Michael J. Castellano 2017 Iowa State University

Does Nitrogen Fertilizer Application Rate To Corn Affect Nitrous Oxide Emissions From The Rotated Soybean Crop?, Javed Iqbal, David C. Mitchell, Daniel W. Barker, Fernando Miguez, John E. Sawyer, Jose Pantoja, Michael J. Castellano

John E. Sawyer

Little information exists on the potential for N fertilizer application to corn (Zea mays L.) to affect N2O emissions during subsequent unfertilized crops in a rotation. To determine if N fertilizer application to corn affects N2O emissions during subsequent crops in rotation, we measured N2O emissions for 3 yr (2011–2013) in an Iowa, corn–soybean [Glycine max (L.) Merr.] rotation with three N fertilizer rates applied to corn (0 kg N ha−1, the recommended rate of 135 kg N ha−1, and a high rate of 225 kg N ha−1); soybean ...


Standardized Research Protocols Enable Transdisciplinary Research Of Climate Variation Impacts In Corn Production Systems, E. J. Kladivko, M. J. Helmers, L. J. Abendroth, D. Herzmann, R. Lal, M. J. Castellano, D. S. Mueller, J. E. Sawyer, R. P. Anex, R. W. Arritt, B. Basso, J. V. Bonta, L. C. Bowling, R. M. Cruse, N. R. Fausey, J. R. Frankenberger, P. W. Gassman, A. J. Gassmann, C. L. Kling, A. Kravchenko, J. G. Lauer, F. E. Miguez, E. D. Nafziger, N. Nkongolo, M. O'Neal, L. B. Owens, P. R. Owens, P. Scharf, M. J. Shipitalo, J. S. Strock, M. B. Villamil 2017 Purdue University

Standardized Research Protocols Enable Transdisciplinary Research Of Climate Variation Impacts In Corn Production Systems, E. J. Kladivko, M. J. Helmers, L. J. Abendroth, D. Herzmann, R. Lal, M. J. Castellano, D. S. Mueller, J. E. Sawyer, R. P. Anex, R. W. Arritt, B. Basso, J. V. Bonta, L. C. Bowling, R. M. Cruse, N. R. Fausey, J. R. Frankenberger, P. W. Gassman, A. J. Gassmann, C. L. Kling, A. Kravchenko, J. G. Lauer, F. E. Miguez, E. D. Nafziger, N. Nkongolo, M. O'Neal, L. B. Owens, P. R. Owens, P. Scharf, M. J. Shipitalo, J. S. Strock, M. B. Villamil

John E. Sawyer

The important questions about agriculture, climate, and sustainability have become increasingly complex and require a coordinated, multifaceted approach for developing new knowledge and understanding. A multistate, transdisciplinary project was begun in 2011 to study the potential for both mitigation and adaptation of corn-based cropping systems to climate variations. The team is measuring the baseline as well as change of the system's carbon (C), nitrogen (N), and water footprints, crop productivity, and pest pressure in response to existing and novel production practices. Nine states and 11 institutions are participating in the project, necessitating a well thought out approach to coordinating ...


Studies On The Crown Rust Of Oats, I. E. Melhus, L. W. Durrell 2017 Iowa State College

Studies On The Crown Rust Of Oats, I. E. Melhus, L. W. Durrell

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

During some seasons crown rust of oats (Puccinia coronata Corda) becomes a serious limiting factor in successful oat production in Iowa. It is not uncommon to have this rust occur in epidemic form one year and the following year to have only a small amount of the disease present. Up to the present time the various factors which influence the growth, development and epidemiology of this rust have not been definitely studied.


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