1.  Nutrient Removal By Major Vegetable Crops In Texas.
Dr. John Jifon, Texas A & M University

Soil nutrient depletion through crop removal is a major limitation to sustainable production especially for horticultural crops which tend to have high fertilizer input requirements. In the long–term, a balance between nutrient inputs and crop removal is required. Although nutrient removal values for many field crops are available, such values for fruitand vegetable crops are rare. Knowledge of nutrient removal amounts is critical in developing fertilizer management practices to sustain yields and quality while maintaining soil fertility. This long–term project will quantify the nutrient uptake⁄accumulation and removal rates of diverse commercial vegetable crops in relation to different yield levels and soil types.

2.  Holistic Approach to Nitrogen and Water Management using Site-Specific Management Zones and Active Remote Sensing for Enhancing Crop Yield, Ethanol and Bio-Fuel Productivity.
Dr. Raj Khosla, Colorado State University

Water in the western Great Plains is increasingly becoming a precious commodity. This has created a new realm of challenges in agriculture. Recent focus is on “limited irrigation” or “irrigating crops only at critical crop growth stages”. Such changes are happening at a time when crops are expected to be raised for meeting the food, feed, fiber and the “fuel” requirements of our society. There are six ethanol plants in Colorado alone that are at different stages of operation or construction. With recent commodity and input price volatility reaching all time highs, there is no room for waste. Concern for enhanced efficiency, productivity, economics and the environment are at an all time high and fluid fertilizers offer considerable advantage in this regard. This research will investigate best management practices such as Site-Specific Management Zones, and Active Remote-Sensing for N management at different levels of water and nitrogen to determine the economic optimum level for crop yield, ethanol and bio-fuel productivity under field conditions. The goals are to enhance nitrogen and water use efficiencies, crop yield, ethanol and bio-fuel productivity, and net return.

3. Effective Manganese Management for Corn and Soybean in Glyphosate-Dominant Cropping Systems
Dr. Tony Vyn, Purdue University

Recent soybean research in Indiana and other states have confirmed that one of the most limiting factors to the achievement of high yields in Roundup Ready® seeding systems is a suspected micronutrient deficiency resulting from applications of glyphosate (Roundup®) to soil, weeds, and directly to glyphosate-resistant soybean. Manganese (Mn) concentrations in soybean plants are frequently lower than optimum, particularly in the week or two following post-emergence glyphosate application, because glyphosate reduces the uptake and translocation of Mn via physiological immobilization of Mn in plants, and because glyphosate is toxic to soil microbes that reduce soil Mn into a form that is available for plant uptake.  The development of RR varieties may also have indirectly lowered Mn uptake efficiencies, and made these varieties more responsive to supplemental Mn than their non-RR counterparts. Glyphosate exuded by roots of resistant soybean plants, as well as by weeds surrounding the soybean plants, is particularly likely to immobilize available Mn in the rhizosphere of soybean roots. Both root Mn uptake, and translocation of Mn to the shoot, are lower when glyphosate residues are present in soil. Soil moisture and pH also affect the relative availability of soil Mn. In this research, we intend to determine the consequences, if any, of cumulative glyhosate applications in RR corn followed by RR soybean on (a) corn yields and tissue Mn concentrations at various stages, and on (b) trifoliate leaf Mn concentrations and yield of RR soybean following various intensities of glyphosate applications over years. Additionally, the long-term goals of this research over the next 3 years are to improve the management of micronutrients such as Mn to help achieve the highest corn and soybean yields possible in cropping systems that are ever more reliant on glyphosate for weed control. 

4. The Effect of Soil Moisture on Residual Fluid and Granular Phosphorus Availability.
Dr. Mike McLaughlin, University of Adelaide

Our recent research has shown that movement of soil water in and around granules can have a marked influence on chemical reactions which control fertilizer effectiveness. When a fertilizer granule is placed in moist soil, it draws soil water towards it and also draws solutes in the soil water into the granule. In a calcareous soil this enhances precipitation of Ca-Phosphate compounds in and around the granule, which reduces granular fertilizer effectiveness markedly. We have discovered this is one of the reasons why delivery (into soil) of exactly the same fertilizer formulation in fluid form can enhance fertilizer efficiency markedly compared to granular products. It is therefore evident that changes in soil water status could markedly affect the reactions occurring in and around fertilizer granules in soil, a phenomenon not well reproduced in most laboratory experiments when nutrients are uniformly mixed throughout the soil. Thus key phenomena that control fertilizer P reactions in soil have not been adequately investigated and characterized.

In addition to a lack of information on the effects of soil moisture status on fertilizer reaction products adjacent to fertilizer granules, or in fluid fertilized zones of soil, there is also a lack of information on the influence of soil moisture conditions on the release of stored soil nutrients. Given that soil reactions which affect fertilizer efficiency (e.g. dissolution, adsorption and/or fixation) can occur quite rapidly after addition of fertilizer to soil, the residual value of fertilizer nutrients and the efficiency of currently applied fertilizer could both be largely influenced by soil water status. We hope to expand on our initial data by extending our testing of the effect of soil moisture on residual nutrient value by separating the period of soil: fertilizer contact from the period of plant growth. This time we will ensure that the period of soil: fertilizer contact has varying soil moisture conditions and the period of plant growth has constant moisture conditions, and we will test this relationship on a range of agricultural soils.

5.  Nitrogen Management For Hybrid Bermudagrass Sod Production.
Dr. Elizabeth Guertal, Auburn University

In sod production, the application of N fertilizers is a balancing act between adding sufficient N to push the crop towards timely harvest, and then sustaining regrowth until the next harvest. Unlike a grain crop, which is harvested in a certain time window, with the grain then stored off-site, sod is 'stored' in the field until the market creates a need to harvest. Thus, N fertilizer is often applied for both agronomic and market needs. A typical N fertilization schedule for Bermuda grass re-establishment is to apply from 4 to 6 lbs N/1,000 sq. ft (175 - 260 lb N/A) during the months when the grass is actively growing. Consultation with local sod producers revealed the following typical N fertilization plan for their sod crops: 1 lb N/1,000 sq. ft (44 lb N/A) in April and May, with a late May/early June harvest to follow, 1 lb N in June, after harvest, and 1 lb N in August. That is a total of 4 lb N/1,000 sq. feet for the growing year, with a harvest in the following spring, after winter dormancy. Others plan to push the sod with additional summer N, allowing the crop to be harvested in the fall. Thus, fertilization issues in sod production include both N rate and N source questions, but the question of N timing also needs to be answered. This is especially true in warm-season grass production, as fall dormancy and spring greenup affect harvest time and N fertilization. While sod production research has largely centered on weed control, there is little fertilizer research. Thus, the objective of this research is to examine various N fertilizer programs (N source, rate and timing) to determine the best program for production and maintenance of hybrid Bermuda grass destined for harvest as a sod crop.

6.  Optimizing Fertigation Protocols for Nitrogen in Almond.
Dr. Patrick Brown, University of California-Davis

In California, fruit and nut tree and vine crop production is the state’s largest agricultural industry with a net farm gate value in excess of $5 billion; the state produces about half of all U.S. fruits and nuts. Greater than 78% of almond growers currently provide N and K fertilization in liquid form, generally as fertigated product; however there has been very little research to explicitly optimize the use of fluid fertilizers and to use the available fertigation systems to optimize nutrient use efficiency and to develop best fertilizers management practice. The goal of this project is to validate and refine the Hydrus 2 model so that an optimal fertigation practice can be established for almond under a variety of management scenarios and fertilizer sources. The specific objectives of this research are 1) characterize water and solute movement within the soil profile, 2) characterize active root location and root development in almond, 3) assess the effect of water/nutrient placement and nutrient source on soil chemical properties and ion movement throughout the soil profile and 4) validate and refine simulation model based on field observations and specific almond characteristics.  The overall long-term outcome is to develop almond specific best fertilizer management practices, derived from crop specific simulation models in order to improve water and nutrient use efficiency.

7.  In-Season Precision Applications of Fluid Fertilizer to Optimize Cotton Productivity and Nitrogen Use Efficiency.
Dr. Frank Yin, University of Tennessee

The technology for real-time remote sensing and variable-rate N fertilizer applications based on Normalized Difference Vegetation Index (NDVI) was first introduced into the United States in 1995. So far, research has mainly been focused on some major grain crops such as wheat and corn. Little investigation has been done on cotton.  
Objectives of the research are 1) to determine the relationships among lint yields, NDVI, NDVI days, leaf N concentrations, N fertilizer rates, soil nitrate contents, and the total amounts of applied N plus soil nitrate using appropriate modeling procedures in 2010, 2) develop an algorithm (prescription) for variable-rate N applications within a field mainly based on the relationship between lint yield and NDVI, 3) to evaluate the effectiveness of the algorithm for variable-rate applications of fluid N fertilizer during the season as compared with the uniform-rate application of dry N fertilizer before or at cotton planting on large field strips in 2011 and 2012 in terms of N fertilizer use and lint yield.

8.  Enhancing Continuous Corn Production under high-Residue Conditions With Starter Fluid fertilizer Combinations and Placements.
Jeff Vetsch, University of Minnesota

Past research by Randall and Vetschfunded by the Fluid Fertilizer Foundation has shown many of the early growth and yield problems associated with corn after corn could be eliminated by using conventional tillage (i.e. moldboard plow) in combination with fluid starter fertilizers. This research also showed fluid starter fertilizers (APP applied in furrow or APP and UAN dribbled on the soil surface) significantly increased early growth of corn by 13 to 43% and corn yield by 5 to 7 bu/A.  This study did not address a commonly asked question, would dual placement (APP in furrow and UAN dribbled on the soil surface) further enhance corn production. Slow early growth, pale spindly plants, and reduced yields are still too common in corn after corn with reduced tillage systems. Sulfur deficiency in corn in the northern Corn Belt has contributed to some of these pale looking plants and documented responses to S have been measured on medium and fine-textured soils in this area. There is really very little data, however, optimal rates and placement of sulfur containing fluid fertilizers for corn. The objective of this research is to provide answers to these questions.

9.  Mobility, Availability and Reaction Products of Different Phosphorus Fertilizer Sources in Various Soils Types.
Dr. Ganga Hettiarachchi, Kansas State University

Millions of tons of P fertilizer are applied to agricultural soils each year and a high proportion of this applied P is rapidly converted to insoluble phosphates that plants have virtually no access. These transformations depend on fertilizer sources and the type of soil. We are interested in evaluating how different form of P reacts in different soils from the different regions of the US at the molecular level using various x-ray based microscopic and spectroscopic techniques such as synchrotron based x-ray fluorescence, x-ray diffraction, and x-ray absorption spectroscopy, and developing relationship between different P reaction products and P availability and/or mobility. This project aims to help answering the difficult question of how to manage crop P nutrition in various US soils more efficiently. The project aims to: 1) understand the interaction between various P sources and various types of soils, and the dissolution and reaction products of P from various P fertiliser sources; 2) understand the mobility and availability of P from different P fertilizer sources in various types of soils; and
3) Integrate the above knowledge with field observations and into recommendations on crop P nutrition.

10. Fluid Fertilizer’s Role in Sustaining Soils Used for Bio-energy Feedstock Production.
Dr. John Kovar, National Laboratory for Agriculture and the Enviroment

Both corn grain and stover are being evaluated as potential bio-energy feedstocks. Recently, the focus has shifted from grain-based to cellulose-based ethanol production, with corn stover being an important feedstock material. In addition to biological conversion of stover to ethanol, thermal conversion of stover to bio-oil, syngas, and biochar is being explored as an alternative to the cellulosic ethanol platform. Regardless of post-harvest processing, the short- and long-term effects of both increasing grain yields and removing stover on soil nutrient cycling, physical properties, and biological activity must be understood to ensure that corn yields meet both current and future demands. The goal of this project is to evaluate the use of N-P-K-S fluid fertilizers to enhance corn grain and stover productivity. Current research suggests that nutrient management is critical and will differ from grain-only systems. Fluids allow flexibility in what is applied and when it is applied. A secondary goal is to demonstrate that biochar application cannot substitute for traditional fertilizer materials, but can play a role in nutrient cycling. This project will involve both field and laboratory research. With a field study, we will evaluate the use of surface or subsurface bands of N-P-K-S fluid fertilizers to optimize nutrient-use efficiency of P, K, and S, and to enhance corn grain and biomass productivity. With both field and controlled-climate chamber studies, we will determine the effect of previous and recent biochar application on P availability and cycling in Clarion-Nicollet-Webster soils common to central Iowa.

11. Improving Corn and Soybean Yields With Starter and Foliar Application of Fluid Fertilizers.
Dorivar Ruis Diaz, Kansas State University

Previous research has shown that direct application of P and K to can have a significant impact on corn and soybean yield. Additional research investigating potential synergistic effects of starter and foliar applications of nutrients to maximize yields in corn and soybean is warranted. Also, increased nutrient demands from more intensive cropping systems and increasingly high yielding crops may also require additional micronutrients for optimum production. Supplementary foliar application of N, P, K, and micronutrients may help to enhance crop yields and improve overal nutrient use efficiency. As a result, there is increasing producer interest in the potential benefits of foliar application of nutrients to complement their overall fertilization program. The overall objective of this study is to evaluate crop response to starter fluid fertilizers in combination with foliar application of macro and micronutrients to maximize corn and soybean yields. Specific objectives include (1) assessment of corn and soybean grain yield and early growth response to starter application of fluid fertilizers and (2) compare responses with and without additional foliar fertilizers. (3) Verify potential soil parameters that could be related to responses to starter and foliar applied macro and micronutrients. (4) Evaluate tissue testing as a diagnostic tool to explain responses to foliar and starter macro and micronutrient application.  (5) Determine if foliar applied fluid fertilizers can maximize yields and increase nutrient use efficiency when combined with starter applied fertilizers.

12.  Nitrogen Source Effects on Nitrous Oxide Emissions from Irrigated Strip-Till and No-Till Corn Production Systems.
Dr. Ardell Halvorson, USDA-ARS

Limited information is available on the effects of nitrogen fertilizer sources on greenhouse gas emissions from irrigated cropping systems. Controlled release and stabilized N fertilizers show potential to enhance N fertilizer use efficiency in agricultural systems. Little information is available on how these controlled release and stabilized N fertilizers might affect nitrous oxide emissions from irrigated cropping systems.  Preliminary results from recent studies indicate that these N sources may reduce nitrous oxide emissions from irrigated cropping systems in northern. Enhanced N use efficiency by crops and reduced nitrous oxide emissions from using these fertilizer products could greatly benefit environmental quality. The overall objective of this project is to evaluate the effects of controlled release and stabilized N sources on nitrous oxide emissions in irrigated cropping systems compared with the commonly used urea and urea-ammonium nitrate fertilizer source.

13. Evaluation of late season application of foliar nitrogen’s impact of grain yield and milling qualities.
Dr. Brian Arnall, Oklahoma State University

It has been documented that late season nitrogen (N) applications, pre and post anthesis, can indeed increase protein, a practice that is common in the production of spring wheat. Agricultural producers are regularly presented with a multitude of products that boast improved yields, protein, or efficiency.  One such product is the low-salt, controlled release, specialty N fertilizer.  Many of these are sold to be applied at flag leaf with a fungicide but are used elsewhere to increase grain protein.  In addition there has been a great deal of discussion as of recent about the functionality of the additional N present in the grain as a result of post-anthesis applications. The objectives of this project is to; 1.  Evaluate the use of UAN (28-0-0) and a low salt fertilizer as a foliar N fertilizer applied at flag leaf and post-flowering to improve hard red winter wheat grain yield, protein, milling, and baking characteristics, 2.  Determine influence nitrogen rate on grain yield and quality and 3.  Evaluate the economical benefit of late season N fertilization.

14. Effect of UAN and ATS Solutions on the Decomposition of Wheat Residue In No-Till Systems.
Dr. Kent Martin, Kansas State University

Many producers recognize the benefit of increased residue on the soil surface, but have problems establishing a good plant stand in high residue situations.  Dry regions have a climate that are not as conducive to residue decomposition as more humid regions.  As a result, some producers resort to tillage as a means for decreasing residue to allow them to get a better stand.  Recommendation that are sometimes made is to apply nitrogen urea-ammonium nitrate (UAN) and/or ammonium thiosulfate (ATS) solutions as a broadcast application to the residue to stimulate microbial activity and subsequent decomposition of the residue.  However, the rate, timing and efficacy of these applications in no-till systems have not been well established.  The objectives of this experiment are to evaluate the effect of UAN and ATS application rates on the decomposition of surface residues and evaluate the timing of UAN and ATS application on the decomposition of residue.

15. Starter Fertilizer Nutrient Component Effects on Corn Yield on High Testing P and K Soils in a High Yield Environment.
Dr. Carrie Laboski, University of Wisconsin

Starter fertilizer placed near or with the seed at planting has been reported to increase early season corn growth, yield, and the rate of plant development resulting in reduced grain moisture content at harvest.  This is especially true at low to optimum soil test P and K levels where nutrient availability is limiting. Several studies have shown positive corn growth responses where soil nutrient availability is high, but nutrient uptake may be low early in the growing season as a result of limited root surface area of young corn plants.  Several published reports of studies conducted in Wisconsin in the 1980’s and 1990’s have evaluated the effect of starter fertilizer on corn yield.  However, none of these studies evaluated individual and interactive effects of nutrient components in starter fertilizer on high P and K testing soils. A significant increase in corn yield potential has occurred since these studies were conducted.  For example, corn grain yields in research plots at Arlington, WI where nutrients levels are non-limiting currently average about 200 bu/acre compared with about 160 bu/acre in the 1980’s.  In addition, atmospheric sulfur (S) deposition has significantly decreased in the past 30 years.  The potentially greater nutrient removal from current high yield potentialcorn hybrids coupled with reduced atmospheric S deposition, justifies the need for current evaluations of the individual and interactive effects of nutrient components in starter fertilizer in order for current high yielding corn hybrids to achieve their full yield potential.

16. Improving theEfficiency of Foliar Fertilizations With Urea With a Urease Inhibitor.
Dr. Derrick Oosterhuis, University of Arkansas

Once in the plant urea is converted to ammonia, by the enzyme urease, and ammonia is incorporated to glutamate, by the enzyme glutamine synthetase. In the literature it is still not clear whether leaf burn resulted from foliar urea application is caused by toxic accumulation of urea or ammonia. In soybean, foliar urea leaf burn is mainly associated with urea accumulation. However; to our knowledge in the literature there is no research done in cotton. Use of urease inhibitor with foliar urea application could be an effective method to help elucidate the fate of urea in cotton leaves. A well known urease inhibitor is N-(n-butyl) thiophosphoric triamide (NBPT) applied in the soil with urea, NBPT has been proved to have high efficiency in inhibiting urease at low concentration in a wide variety of soils . Preliminary data indicated that addition of NBPT to foliar urea application increased cotton yield, with values significantly higher than urea alone. Furthermore, seedcotton yield of NBPT + foliar urea treated plots that received only 75% of the full recommended N rate was statistically equivalent to the plots that had 100 % of the N rate. Thus, the use of urease inhibitor with foliar urea fertilization could have the potential of enhance N assimilation in plant leaves, which could help improve foliar N management in crops. The main objective is to study foliar urea assimilation in cotton plants and how the use of the urease inhibitor NBPT will affect the efficiency of foliar urea application. An additional objective is to understand if cotton leaves treated with urea, suffers from toxicity of urea or ammonia. With a better understanding of the physiological effects of foliar urea application and the use of a urease inhibitor, we expect to improve foliar N management in crops.