1. Variable Rate Starter Fertilization Based On Soil Attributes. (year 3 of 3)
Jeff Vetsch, University of Minnesota
Variable rate application of fertilizer has been widely adopted across much of the Corn Belt. The logical next step is to variable rate apply starter fertilizers. Our hypothesis is on low P testing and/or P fixing soils a fluid starter fertilizer, like ammonium polyphosphate (APP), applied in-furrow will result in increased yield, fertilizer use efficiency and economic return compared with a traditional broadcast application. To test our hypothesis we propose a research study that compares multiple rates of APP applied in-furrow at planting. These rates will be blocked in small research units across a field containing soils and soil variability (low to high pH) typical of the region. The starter rates will be applied within blocks of with and without broadcast P fertilizer. The with and without broadcast P blocks will allow us to compare the efficiency of starter P to broadcast P across the landscape while simultaneously evaluating the benefits of starter P at various rates in addition to broadcast P at traditional rates.

2.  Use of Remote Sensing In Cotton To Accurately Predict the Onset Of Nutrient Stress For Foliar Alleviation For Optimizing Yield and Quality. (year 3 of 3)
Dr. Derrick Oosterhuis, University of Arkansas
Cotton lint yields in the US Cotton Belt are only about 30% of the theoretical potential of 7 bales/acre (Baker and Hesketh, 1969), indicating that there are numerous parameters restricting the cotton crop from achieving its potential.  This has been clearly associated with environmental stresses, including drought, high temperatures, and nutrient deficiencies, particularly during the sensitive flowering and boll fill period.  Plant response to stress has been well documented. However, a method to detect and ameliorate these stresses before yields are compromised still needs to be developed.  One method which has the potential to provide instantaneous, on-the-go information on crop stress status is remote sensing. Remote sensing technology, the science and understanding of which have improved dramatically in recent years, is easily available, but the accuracy of how it relates to actual crop stress responses and effect on yield is still uncertain.  To quantify the onset of nutrient stress (N and K) in the field using aerial and ground-based remote sensing and ground-proof this with sequential plant indicators of stress.

3.  Development of Intensive N Management Strategies to Enhance Yield and Nitrogen Use Efficiency in High Yielding Dryland and Irrigated Corn. (year 3 of 3)
Dr. Dave Mengel, Kansas State University
Nitrogen management is becoming one of the more complex aspects of modern corn production.  Changes in plant genetics, earlier planting dates, larger farm size which compresses time available for field work per acre, equipment innovations, increasing fuel and N costs, as well as concerns with potential environmental contamination all contribute to this increased complexity. Balancing time and financial resources in an effort to maximize yield and profitability, while still being a good environmental steward has become difficult for producers. Recent advances in crop sensor technology may provide a better estimate of the interaction of these soil and plant factors by using the growth and color of plants at vegetative growth stages as an indicator of N need and demand of a growing corn crop (Raun, et al., 1998; Tucker, 2010) and help us make some of these decisions more accurately, rapidly and on the go.

4.  Improving Cotton Production Efficiency with Phosphorus and Potassium Placement at Multiple Depths in Strip Tillage Systems. (year 3 of 3)
Dr. William Frame, Virginia Tech University
The development of higher yielding and earlier maturing cotton varieties has created a greater demand for nutrients during bloom and boll set. Potassium demands are great during this stage of development and with these higher yielding early maturing varieties potassium deficiencies have been documented in soils testing high in plant-available potassium.  Foliar applications of potassium nitrate have been recommended where deficiencies are expected to occur, or in response to visual deficiency symptoms (Crozier, 2010). Waraich et al. (2011) found that the number of foliar applications and rate of potassium nitrate applied at flowering, 14 days after first flower (DAF), and 28 DAF had significant impact on yield and fiber quality. If deficiencies are occurring, foliar application may correct the deficiency, but the yield potential of the crop may have been adversely affected. This is especially true since earlier maturing varieties behave more like determinant flowering plants than the more indeterminate mid- to full season cotton varieties. This equates to shorter boll fill periods where the yield potential of the crop is determined. Applying potassium throughout the rooting zone may allow for greater availability compared than broadcast applications, thus minimizing potassium deficiencies, maximizing the potassium use efficiency of cotton, and increasing lint yields.

5.  Precision-Water, -Nitrogen and -Seed Management for Enhancing Efficiency, Productivity, and Profitability of Irrigated Cropping Systems. (year 3 of 3)
Raj Khosla, Colorado State University
In this project we will evaluate variable rate seeding along with precision water and nutrient management by researching and demonstrating the most productive, efficient, profitable and sustainable variable rate-water, -nutrient and –seed management strategies for irrigated cropping systems. Our specific objectives are: 1) Quantify spatial and temporal variability in soil water balance across the 22 acre precision pivot equipped field, 2) Develop early season (corn growth stage V4-V6) in-season precision nitrogen management system for irrigated corn and 3) Evaluate variable rate seeding in conjunction with variably managed water and nutrients.

6.  4R Nutrient Stewardship Research Initiative.
Fertilizer is a component of sustainable crop production systems, and the fertilizer industry recognizes the need to efficiently utilize these nutrients. The 4R philosophy is an innovative and science-based approach that offers enhanced environmental protection, increased production, increased farmer profitability, and improved sustainability. The concept is to use the right fertilizer source, at the right rate, at the right time, with the right placement. Implications of the 4R nutrient stewardship system will spread far and wide through agriculture and society as a whole. For fertilizer use to be sustainable, it must support cropping systems that provide economic, social, and environmental benefits. Two goals within the initiative include establishing 4Rs as a recognizable strategy for economic, social, and environmental sustainability and expanding the adoption of 4R nutrient stewardship as well as the awareness of these efforts to federal and state program officials.

7.  Efficient Management Of Water and Nutrient resources: Assessing the Potential For Drip Irrigation and Fertigation. (year 2 of 3)
Dr. Fred Below and Ross Bender, University of Illinois
While irrigated crop acreage in Illinois is limited in scope (435,000 acres or approximately 2% of total crop acres as of a 2005 survey), it has experienced a 48-fold increase compared to the first estimate of irrigated Illinois crop production in 1950. Although irrigation is often a necessity in areas with sandy soil textures (e.g., Mason County), use of irrigation in other areas may become attractive to crop producers as a strategy to reduce annual yield variability associated with insufficient precipitation or for high-value crops such as seed corn production. As such, irrigated crop acres in Illinois are anticipated to expand by an additional 40% by the year 2025. Sub-surface drip irrigation (SDI) is not a new technology and has been used for many years in the production of high-value vegetable and fruit crops such as tomato. More recently, it has been adopted for commodity rows crops such as corn and cotton as an alternative to center-pivot or flood irrigation.  The objectives of this project is to; 1) Investigate drip irrigation as a possible strategy to improve the efficiency of nutrient uptake and use when liquid nutrients are applied at key growth stages compared to a conventional granular broadcast and side-dress fertility program and 2) Understand how drip irrigation and fertigation can be optimized in a high yield agronomic system with complementary agronomic management practices including hybrid and variety selection and crop protection.

8.  Potassium Fertilization for Southern Cotton: New Genotypes & Questions. (year 2 of 3).
Dr. Elizabeth Guertal, Auburn University
The study of potassium (K) fertilization of cotton has a long history (Oosterhuis, 2002), traceable to the first reports of the importance of K for prevention of ‘rust’ of cotton (Atkinson, 1891).  Southern cotton fields have a long history of productivity; with cotton long the top agricultural commodity crop in the southern cotton belt.  In 2013, the National Cotton Council’s 30th Annual Early Season Planting Intentions Survey indicates that growers intend to plant 9.01 million acres of upland and Pima cotton across the cotton belt.  In reality, this represents a 20-year low in intended acres, as corn and soybean prices remain strong.  Regardless, cotton production is a strength of the agricultural south, a major economic engine in rural areas, and continued study of basic management practices is needed. Because the literature for K fertilization of cotton is inconsistent in K fertilizer recommendations, and because K source and rate information is still lacking, the Objective of this research proposal is to study the combined and separate effects of foliar K rate and source for high-yield cotton production, and to do this with new generation cotton cultivars.

9.  Balanced Nutrition and Crop Production Practices For The Study Of Sorghum Nutrient Partitioning and Closing Yield Gaps. (year 2 of 3)
Dr. Ignacio Ciampitti, Kansas State University
More research information is needed as related to the interactions among crop production practices and nutrient fertilization for optimizing inputs and maximizing sorghum yield at very diverse environments. In addition, previous information related to nutrient concentration in different plant tissue for sorghum in Kansas (and the region) needs to be updated (Vanderlip, 1972). Information for modern hybrids is scarce, and the effect of combined management practices on the nutrient partitioning process is relatively unknown. Balanced nutrient application for maximizing yields under crop management practices should be further studied for grain sorghum under diverse environments around the state. The overall research goal is to identify the effect of nutrient fertilizer applications and their interactions with diverse management factors that contribute to high yields, and to quantify how those practices impact yield formation and nutrient uptake processes. A secondary objective will be to quantify the yield potential for each particular environment evaluated, and to determine the contribution of the balanced nutrient fertilization and each specific crop management factor in reducing sorghum yield gaps (herein understood as the difference between the potential yield and the current farmer practice).

10.  Effect of N Source, Rate and Application Time On Spring Wheat Grain Yield and Protein Content. (year 2 of 3)
Dr. Olga Walsh, Montana State University
At present, there are few guidelines developed for effective and efficient use of liquid N fertilizers in spring wheat in Montana. This includes more traditional liquid products like urea-ammonium nitrate solution, urea solution and urea formaldehyde/triazone products. In order for wheat growers to fully benefit from incorporation of various liquid N fertilizers into their operation, additional research studying grain yields and grain protein is desired. A comprehensive liquid N product utilization strategy, including guidelines on the optimum N rate, time, and method of application will be researched. The specific objectives include: Compare the efficacy of 3 liquid N fertilizers – urea ammonium nitrate solution (UAN), liquid urea, and urea formaldehyde/triazone products applied to spring wheat, Determine the optimum N rate of liquid fertilizers by evaluating a range of N rates and Identify the appropriate time of liquid N fertilizer application (early-season application at Feekes 5 and/or flowering at Feekes 10.5).

11.  Using Liquid Sources Of Potassium Fertilizer In Highbush Blueberry. (year 1 of 3)
Dr. David Bryla, USDA-ARS Corvallis, OR
Consumption of blueberries has increased rapidly in recent years, primarily due to promotion of their health benefits and to greater availability of the fruit year round. Recently, we determined that drip fertigation with various fluid NH4-N sources, including ammonium sulfate, urea, and urea sulfuric acid, produced more growth and greater yield than conventional granular fertilizers in highbush blueberry. Potassium is usually applied to blueberry as potassium sulfate.  Potassium chloride (muriate of potash) is also sometimes used but is not recommended because blueberry is very sensitive to chloride.  Other potential sources include mono potassium phosphate, which is largely a source of P, and potassium thiosulfate (KTS).  The latter may be particularly useful in high pH soils such as those in California and eastern Oregon and Washington because the product is acidifying (thiosulfate is oxidized by Thiobacillus bacteria to produce sulfuric acid).  Potassium nitrate is also a popular K fertilizer available for fertigation, but it is expensive and a poor N source (i.e., NO3-N) for blueberry. The goal of proposed project is to develop guidelines for K fertigation in blueberry using KTS. The results will help growers improve production in the crop and enhance fruit quality for consumers.

12.  Evaluation of Cotton Yield, Quality, and Growth Response to Injected Liquid K. (year 1 of 3)
Dr. Gaylon Morgan, Texas A&M
Previous research in 2012 and 2013 trials at six field sites with a previous history of K deficiencies were conducted in the Blacklands of Texas and the Upper Gulf Coast region. Lint yield were significantly increased with increasing K rates in fields with 150 ppm or less.  See Wharton and Williamson county trial results below.  Liquid K injected had a greater positive effect on lint yield compared to granular K incorporated.  Additionally, the injected K increased yields even at the higher application rates and at the locations exceeding the current soil threshold level of 125 ppm of K.  The injected K improved length, strength and uniformity at the Williamson site. As a result of the substantial yield response in Texas in 2012 and 2013, there is a strong interest in evaluating liquid injected applications of K across the Cotton Belt at a minimum of eight locations.

13. High-Yielding Soybeans: Genetic Gain X Fertilizer N Interaction.  (year 1 of 3)
Dr. Ignacio A. Ciampitti, Kansas State University
The overall research goal is to study the contribution of nitrogen on high-yielding soybean systems under diverse germplasm and production practices. Closing yield gaps (actual on-farm yield vs. genetic yield potential) in a long-term perspective will require an improvement in the utilization of the available resources, which must be attained via implementation of better management decisions. Impacts of these diverse agricultural scenarios or technology packages on biomass and nutrient accumulation for the season-long and yield formation will be quantified with the goal of more properly understanding how these systems can sustainably reduce yield gaps through improving the efficiency in capturing and utilizing natural resources and inputs (e.g., sunlight, water, and nutrients) for increasing productivity at the cropping-system-scale.

14. Evaluation of Corn Population and Sidedress Applications of Potassium and Nitrogen on Corn Grain Yield.  (year 1 of 3)
Dr. Robert Miller, Colorado State University
Recent research from a potassium fertilizer project conducted by Midwest Independent Soil Samplers across 61 locations across Nebraska, Iowa, Illinois, Wisconsin and Indiana 2011-2013, indicates a 43% response to K fertilizer K on soils with STK levels 85 - 600 ppm, with an average response of 9 bu/ac (Miller, 2012).  Results were consistent over locations and years. Generally, soils with STK stratification by depth showed the greatest yield response.  Increasingly corn growers have shown interest in side dress applications of N fertilizers, which improve efficiency and minimize losses.  Vegetative growth uptake of N and K are generally paired in a ratio of 1:0.8 (Karlen et al, 1987), thus the application of both of N and K during early vegetative growth stages is likely to improve corn yield than N alone.   With increasing yield and greater interest in season nutrient applications, the objective of this project is to evaluate corn response to side dress applications of N and K across a range of corn populations, and to assess types of K application.   

15. Comparison of ATS placement methods to enhance yield of continuous corn.  (year 1 of 3)
Drs. Dan Kaiser and Jeffery Vetsch, University of Minnesota
Research in Minnesota has clearly identified the need for sulfur for corn production. Placement
comparisons (band vs. broadcast) of sulfur on medium and fine textured soils have not been
researched for many years. Many farmers want to apply sulfur with their broadcast P and K in the fall but are concerned with loss of sulfate sulfur prior to corn planting. Liquid fertilizer sources containing sulfur such as ATS provide a viable alternative for band application with the planter or for a broadcast pre-emerge application with or without herbicides. Concentrating sulfur near the roots where it is needed the most early in the growing season may be a more efficient use of fertilizer but we do not have any current research comparing band and broadcast application of sulfur. If growers wish to apply ATS over the top as a pre-emergence application we need more information whether this type of application is as effective as an application of AMS at or prior to planting. We currently do not suggest changing S application rate based on the use of ATS versus AMS. The relative effectiveness of ATS placement is needed in order to fine tune new guidelines for sulfur application to corn. The objectives of this project are:1. Determine if a surface band application of S as ATS is more efficient than broadcast application of ATS or AMS 2. Determine if pre-emerge broadcast application of ATS is as an effective source of applying S compared to AMS broadcast at or before planting in continuous corn.