The Fluid Fertilizer Foundation is committed to research about the benefits of fluid fertilizers in ALL programs.



The Fluid Fertilizer Foundation has researched fertigation for agronomic and horticultural crops, the role of S in fluid fertilizers, the value of micronutrients in fluid starters, the development of lime suspensions and their agronomic benefits, the flexibility of starter placement for reduced tillage crops, the ongoing importance of high N starters, and much more!

Click to View Our Current Research Projects:

Evaluation of Corn Population and Sidedress Applications of Potassium and Nitrogen on Corn Grain Yield. (year 3 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.   

Comparison of ATS placement methods to enhance yield of continuous corn. (year 3 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 to determine if a surface band application of S as ATS is more efficient than broadcast application of ATS or AMS and to 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.

Fluid Sources For Micronutrients In Starters For No-Tillage Corn and Soybean In Argentina. (year 3 of 3)

Dr. Ricardo Melgar, INTA, Pergamino, Argentina

Recent soil nutrient surveys in the main grain producing region of Argentina indicate a generalized and growing deficiency of zinc and boron . Although awareness of farmers is still low, companies start to offer a variety of possible sources for coping with the situation, mainly foliar formulations and some imported complexes to apply to soils at planting. Usual ways to provide micronutrients to annual crops can be classified as to soil application, foliar sprays and seed coatings. The objectives of this work is to determine the best formulation and placement for providing micronutrients no-till Argentine crops.  To compare two granular formulations with a fluid source of micronutrients applied to soil at sowing for high grain yields of corn and soybean.

Development of Variable Rate Nitrogen Recommendation Algorithms to Enhance Yield and Nitrogen Use Efficiency in High Yielding Dryland and Irrigated Corn. (year 3 of 3)

Dr. Ray Asebedo, 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 and soil sensor technology may provide a better estimate of the interaction of soil and crop yield determining factors.  The utilization of pre-plant on-the-go soil sensor technology for quantifying soil characteristics, coupled with in-season crop sensor technology at specific yield determining growth stages may provide in-depth agronomic information for improving the efficiency of N management in corn. The objectives of this work is to; Measure the impact of N rate and time of application (N management system) on yield, profitability and nitrogen use efficiency in high yielding corn production, to evaluate the efficacy of prototype agronomic algorithms that utilize soil and crop sensor technology to determine the optimum N rate with variable rate applications (VRA) and  to compare the costs and profitability of sensor-based VRA N management, spad meter N management, and traditional pre-plant N management.

Fluid Nitrogen-Sulfur Fertilizer Formulations To Mitigate Sulfur Deficiencies and Maximize Cotton Yields In The Upper-Southeast Coastal Plain. (year 3 of 3)

Dr. William Hunter Frame, Virginia Tech

Environmental regulations, such as the Clean Air Act, have reduced the S emissions from coal burning power plants, thus reducing atmospheric S deposition on cropland. Historically, S deposition contributed to acidification of surface waters, nutrient enrichment of surface waters, decline of sensitive forests, and impacts on ecosystem biodiversidity (E.P.A, 1999). That same deposition provided a free source of N and S in crop fields and mitigated S deficiencies in areas where natural S fertility is low. As a result of reduced atmospheric S deposition, S responses in coarse textured soils with low organic matter have increased across the southeast and mid-south U.S. growing regions. The objectives of this project is to evaluate granular and fluid N sources with varying S application rates on cotton in the upper southeast coastal plain and to determine the effect of high N:S ratios in side-dress fluid N sources at varying N application rates on NDVI, petiole and leaf N:S ratios, and lint yield.

Improving Corn Yields and Nitrogen Use Efficiency (NUE) With Late-Vegetative N Applications Using High Clearance Equipment. (year 3 of 3).

Dr. Dorivar Ruiz Diaz, Kansas State University

Higher yield potential and stay-green characteristics of modern corn hybrids require improvements to current fertilizer N management practices. New corn genetics may benefit from late N applications in combination with management practices such as late fungicide applications. The combination of late N and fungicide may benefit corn hybrids that may have the capacity to stay green longer and until much later in the grain filling period contributing to significant yield increase. The effect of late fungicide applications to help maintain leaf health and its effect on N use has not been evaluated. High clearance equipment are becoming widely available and producers and retailers can utilize this equipment not only for spraying chemicals; but also for the application of fluid fertilizers at late-vegetative stages. The overall objective of this study is to assess the value of split N application with late vegetative application time with emphasis on yield and NUE. Specific objectives include (1) evaluate nitrogen use efficiency (NUE) with split N applications including late-vegetative N application, (2) evaluate the benefit of fungicide applications on yield and NUE with late N applications and (3) assess the value of foliar N the application using N sources with urea ormaldehyde/triazone during late vegetative stages (VT-R1).

Effect Of Method Of UAN Application On N losses Via Ammonia Volatilization And Surface Runoff. (year 3 of 3)

Dr. Miguel Cabrera, University of Georgia

Surface application of UAN solution to grasslands results in losses of ammonia (NH3) that vary depending on environmental variables such as temperature, relative humidity, rainfall, and soil water content. Our previous research on Southern Piedmont pastures in Georgia has shown NH3 losses from UAN ranging from 6 to 33% of the applied N (Vaio et al., 2008). These emissions of NH3 to the atmosphere decrease the efficiency of the applied N although the lost NH3 is eventually deposited back to soil or water through wet and dry deposition. Ammonia deposition in riparian and forest areas contributes to soil acidification through nitrification and acts as an indirect source of nitrous oxide (N2O), a greenhouse gas (Mosier et al., 1998). In surface waters, deposition of NH3 may lead to eutrophication in streams, rivers, and lakes (Lewis et al., 2011). Thus, identifying practices that reduce NH3 losses from grasslands is important to improve UAN efficiency and to decrease potential environmental problems. The objectives of this work are to evaluate the effect of method of UAN application (broadcast or dribble) to tall fescue/bermudagrass grasslands on: forage yield and apparent N recovery, rate of urea hydrolysis, NH3 volatilization and surface runoff losses of inorganic N and urea.

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.

Nitrogen and Phosphorus Management to Increase Nutrient Use Efficiency and Corn Grain Yield. (year 2 of 3)

Dr. Fred Below and Brad Bernhard, University of Illinois

The fertility requirements for modern high-yielding corn have been recently identified by our laboratory (Bender et al., 2013). Nitrogen uptake by corn follows a sigmoidal pattern over time with two-thirds of the total plant uptake acquired by the VT/R1 growth stage (Bender et al., 2013). From V8 to R1, corn takes up N at a rate of 7 lbs of N/Acre/day for 21 continuous days. Matching corn nutritional needs by supplying nutrients at the right time and place is critical for optimizing nutrient use and grain yield. In contrast, one-half of the total P uptake by corn occurs after VT/R1, suggesting that a season-long supply of P is critical for corn growth (Bender et al., 2013). Applying nutrients when the crop is actively growing and the nutrient demand of the crop is high decreases the likelihood of fertilizer degradation, fixation, nutrient loss, and environmental pollution. The principal objective of these experiments is to investigate the possible improvement in nutrient use efficiency through the use of innovative technologies allowing greater availability of fertilizers at the optimal timing and rate. A. Investigate different N and P fertilizer application methods, timings, and the use of fertilizer additives to improve the efficiency of nutrient uptake in corn. B. Understand the role proper fertilizer source, rate, placement, and application timing plays on corn grain yield. The goal is to maximize corn grain yield through the use of innovative fertilizer enhancement products, application methods, and timing within high-yield management systems.

Optimizing Soybean Nutrition and Yield with Advanced Foliar Delivery System. (year 2 of 3)

Dr. Shaun Casteel, Purdue University

The opportunity is prime with the discoveries that have been documented in modern soybeans (nutrient demands, nutrient uptake/remobilization patterns, leaf retention, and late season development) as well as new application technologies. 360 Yield Center has developed new fertility management systems over the past few years including the Y-Drop® and Undercover®. The Undercover® unit allows up to four multidirectional spray nozzles to be positioned in the middle of the crop canopy (Fig. 1). This can be used for fungicide, insecticide, and nutrient applications. This application technology could be used to correct nutrient deficiencies in the middle of the canopy, especially of those immobile nutrients like Mn or variable mobile nutrients like S. It could also be used to enhance the leaf nutrition (e.g., N, K, S) in the middle of the dense canopy during pod development and seed fill of soybean. The advanced foliar delivery system could also match up the optimal placement of fungicides and insecticides (depending on the targets) with foliar fertility. Our goal is to increase soybean yields with enhanced foliar management of nutrients and protectants. Our objective is to determine the optimal canopy placement (i.e., top, middle, both) for foliar nutrition, foliar protection, and foliar combinations. We will evaluate the traditional broadcast (over-­the-­top) to the new Undercover® technology as affected by:

  1. Soybean development: early to late reproductive stages
  2. Nutrient mobility in the plant: nitrogen, potassium, sulfur, manganese
Can humic substances be used as “enhancers” to alter fertilizer-phosphorus reaction pathways in soils? (year 2 of 3)

Dr. Ganga Hettiarachchi, Kansas State University

This project will, for the first time, provide a comprehensive assessment of the dominant solid P species formed in soil following addition of liquid P fertilizers with and without fertilizer enhancers and link the effect these treatments have on P fate and transport. Additionally, this project will also help to develop sound standard protocols for evaluating the role of fertilizer enhancers and their effects on fertilizer acquisition efficiency in future investigations. Unraveling the underlying interactive reaction pathways and mechanisms that drive P pool partitioning will herald in a new age of fertilizer development and crop fertility management providing farmers the nutrients they need with minimal risk to human and environmental health. This project aims to further explore the behaviour of humic substances in fertilized soils and their influence on P fertilizer use efficiency. The main objectives are to: 1) Assess the mobility and reaction products of APP, MAP and DAP applied to soil with/without co-application of humic substances/select organic compounds; 2) Determine how humic substances/select organic compounds impact P fractionation and plant availability in native soils with/without P amendment as APP, MAP and DAP; 3) Integrate spectroscopic P speciation techniques with traditional wet chemical analysis to provide a more comprehensive understanding of the role humic substances/organic compounds play in P cycling and how P fertilizer acquisition efficiency can be improved in select soil types.

Evaluation of Foliar Fertilizers in Cotton for Plant Growth, Reproductive Development, Yield, Fiber Quality, and Financial Return (year 1 of 3)

Dr. Seth Byrd, Texas A&M AgriLife Extension Service

Cotton lint yields have increased an average of 10 lbs/a/year over the past three decades, resulting in average yields going from 575 lbs/a to 875 lbs/a. Despite yield increases, most nutrient management recommendations were established decades ago and have not been re-evaluated since that time. This higher yield potential raises questions on utilizing dated nutrient recommendations based on cotton yield goals and different yield limiting factors than decades ago. Some of the major changes in the cotton industry that impact yield and nutrient management are the eradication of boll weevil leading to adoption of indeterminate cotton varieties, smaller seed size leading to changes in source:sink relationships, earlier and more compressed boll loading, and increased importance on fiber quality. While many of the foliar products supply the plant with low rates of either single macro nutrients or a mix of macro and micro nutrients, these products are also applied relatively late in the growing season, and thus may be sustaining or improving plant function compared to soil applied nutrients alone. The objectives of this study are threefold: 1) determine if foliar applications of macro- and micronutrients have the potential to increase yield and fiber components of cotton when used as supplements to soil applied nutrients at levels to reach 100% of soil test recommendations; 2) determine if the soil test recommendations remain adequate for current varieties and there yield potential; and, 3) quantify the return on investment from the utilization of various fertility programs and application costs and the resulting cotton yield and fiber quality.

Nitrogen Management for High-Yield High-Protein Wheat (year 1 of 3)

Dr. Romulo Lollato, Kansas State University

Short availability of high-protein winter wheat created a niche market that rewarded producers able to deliver wheat with greater than 10.5% protein in many elevators in the region. Premiums ranged from $0.40 to over $1.20 per bushel, depending on location and crop percent protein. This new emerging market spiked producer and consumer interest in management practices necessary to ensure high-yielding high-protein winter wheat.

Precise management of nitrogen (N) fertilizer rate and time is mandatory to maximize wheat yields and protein concentration.  Recent research results, collected from a broad range in yield and protein magnitudes, suggest three different phases in the nitrogen x relative protein x relative yield relationship: i) a deficient phase for both yield and protein when total season N was <148.7 lbs N/ac; a phase where N is sufficient for yields but  not for protein (total seasonal N between 148.7 and 168.9 lbs N/ac); and finally a phase where N is excessive for both yield and protein (total seasonal N > 168.9 lbs N/ac).

The Objectives of this study are: (1) To test whether the thresholds developed in preliminary research (e.g. 148.7 and 168.9 lbs N/ac) hold true across different winter wheat varieties and N management strategies; (2) To determine the importance of N timing and rate in wheat nutrient uptake, partitioning into plant components, and maximization of yield and protein in high-yielding systems.

Evaluation of Post-Emergence Fluid Potassium Fertilizer Application for Corn and Soybean Production (year 1 of 3)

Dr. Antonio P. Mallarino, Iowa State University

There are good reasons to conduct fluid K fertilizer placement and time of application research with a new focus. Since grain prices have dropped significantly and there is large uncertainty in soil testing for K, farmers and crop advisors wonder if K fertilizer rates can be reduced by complementing pre-plant fertilization with post-emergence applications. Sidedressing of N is commonly done for corn, although is not a practice adopted by the majority of farmers. Potassium sidedress research with non-irrigated corn or soybean is scarce and incomplete, mainly because most scientists believe yield responses would be uncertain and variable due to the late application or moisture limitations. Given the low mobility of K in medium and fine textured soils, it is generally accepted that without irrigation, injecting fluid K fertilizer is the best option to sidedress K. Therefore, there is a need to investigate the corn and soybean response to sidedressed fluid K fertilizer after applying different pre-plant soil K fertilizer rates in different soils and years.

The objective of the proposed study is to evaluate how sidedressed injected liquid K interacts with pre-plant broadcast K fertilization rates, soil-test K levels, and the yield level at affecting grain yield and plant tissue K concentration in corn and soybean. It will not duplicate but rather complement any recent or ongoing research.

Combining 4R Nutrient Management and Ecological Intensification to Advance Corn Production (year 1 of 3)

Jeffrey A Vetsch, Univ. of Minnesota

The goal of ecological intensification (EI) in crop production is to accelerate yield gains in a sustainable and environmentally conscious manner by utilizing the best science and management available. There is great potential to link EI and 4R nutrient stewardship to lead agriculture to a more productive, profitable, and sustainable future. Many management practices have been shown to increase yield of corn (maize), including hybrid selection, planting rate, residue management, tillage system, water management, pesticides, and nutrient management.  Some of these yield-enhancing practices have seen widespread adoption while others have not. Research and extension are needed to demonstrate the potential gains in yield and economic net return that could be attained by corn producers who adopt these and other practices.

The Global Maize Project (GMP) is a research project initiated by the International Plant Nutrition Institute (IPNI). It compares the typical farmer practice (FP) to EI as determined by local agronomists and scientists. Combining the concepts of EI and 4R nutrient stewardship is essential for advancing sustainable intensification of corn production.

The goal of this research is to address the following questions that have been repeatedly asked by farmers and the ag industries they support:

  1. What yield levels are possible in Minnesota?
  2. How far is current production from that which is possible?
  3. Is our current scientific knowledge, when properly integrated, capable of creating marked improvements in system performance over current farmer practices?
  4. Can current university nutrient recommendations attain and maintain the high yields that are possible?