Nitrogen Losses: Meta-analyses on Fertilizer Management- Results and Recommendations.

Crops: Alfalfa Almonds Apples Barley Beans (dry) Canola Citrus Clover Corn for grain Corn for silage Cotton Cucumbers Green beans Hay Hazelnuts Hops Mustard Peanuts Pecans Potato Rice Rye Ryegrass Sorghum Soybeans Spinach Strawberries Sugar beets Sugarcane Sweet corn Tart cherry Tobacco Tomato Winter wheat Wheat
4R Practices: Metadata Project

Nitrogen Losses: Meta-analyses on Fertilizer Management- Results and Recommendations.

Lead Researcher:

Dr. Alison Eagle

Scientist

Environmental Defense Fund

Start Date: 2014

End Date: 2015

Collaborating scientists and universities

  • Dr. Laura Christianson, University of Illinois
  • Dr. Rachel Cook, Southern Illinois University
  • Dr. R. Daren Harmel, USDA-ARS
  • Dr. Fernando Miguez, Iowa State University
  • Dr. Song Qian, University of Toledo
  • Dr. Dorivar Ruiz Diaz, Kansas State University
  • Dr. Cristie Preston, Nutrien, Ltd.

Project Summary

Growing population and consumer demand require that agriculture continue to increase productivity while managing environmental impacts. Efficient farm production and environmental management needs a well-informed and scientifically-based strategy. To do this, the ever- increasing volume of data from agricultural field research must be summarized, assessed, and interpreted. Meta-analysis of experimental data can be used to find overall or widespread benefits of management practices that may be difficult to fully understand with individual research projects, most of which are limited to particular climatic and soil conditions. Policy makers and producers would like to see broader application of practices that can have water or air quality benefits while maintaining or enhancing production. However, accurate scientific information is needed to know how to do this best, where it will work, and how it can be cost- effective.

This project will summarize the results of all five 4R Research Fund supported meta-analysis projects, and detail the databases generated, as well as the potential for linkages between them or with other databases. This summary will allow for a discussion on the implications of 4R nutrient management that go beyond that possible in single research papers or even in the individual meta-analysis projects. 

Project Goals:

  • Summarize the 4R Research Fund-supported meta- analyses, noting how the combined data and results can advise best practice 
  • Summarize the critical data gaps found by the 4R Research Fund-supported meta-analysis teams and provide recommendations for field researchers to aid future data synthesis efforts in making the most effective use of their data following initial publication. 

Project Results:

  • Alleviate challenges in meta-analysis by implementing the following in individual research projects:
  • use common meta-data protocols for consistent units and terminology;
  • clearly define treatments and controls;
  • provide complete, tabular, full-factorial response data for each year and location;
  • collect and report a minimum set of auxiliary data;
  • establish requirements for data curation and repositories in funding and publication cycles.

Annual Reports

2017

Publications

Relationships of Nitrous Oxide Emissions to Fertilizer Nitrogen Recovery Efficiencies in Rain-fed Corn Systems

Crops: Corn for grain
4R Practices: Rate Time

Relationships of Nitrous Oxide Emissions to Fertilizer Nitrogen Recovery Efficiencies in Rain-fed Corn Systems: Research Foundation Building

Lead Researcher:

Dr. Tony Vyn

Department of Agronomy, Henry A. Wallace Chair in Crop Sciences

Purdue University

Start Date: 2014

End Date: 2015

Collaborating scientists and universities

  • Dr. Rex Omonode, Purdue University

Matching Funds

  • USDA – National Institute of Food and Agriculture

Project Summary

Despite many years of research on nitrous oxide (N2O) emission from corn experiments with various N management treatments applied, little is known about the relationships between N2O loss and plant nitrogen recovery efficiency (NRE). Our review publication (Omonode et al., 2017) provided a summary of the known relationships with existing North American data, but in most cases N2O and NRE data are seldom collected and/or reported from the same experiments. Thus, although it is commonly assumed that higher NRE following environmentally-beneficial N fertilizer management practices will lead to lower N2O emissions, too little evidence exists for this assumption across the range of corn/N management tracks. The overall aim of this project was to provide more concrete field research data to either support or reject this hypothesis. Our specific objective was to determine the relationships between seasonal N2O emissions, whole plant nitrogen (N) uptake, and NRE in rainfed corn under different tillage and nitrogen (N) fertilizer management systems.  

Project Goals:

  • Analyze corn stover and grain N concentrations from whole-plant biomass samples taken at the R6 stage in ongoing Indiana studies involving N source (UAN and NH3 with and without nitrification inhibitors), N rate (from a 0 N control to as much as 240 pounds N/acre), and tillage system interactions with N losses. 
  • Expand the N timing research already underway in Purdue’s 4R Nutrient Stewardship research (2015-2017) to include intensive sampling of both growing-season N2O emissions as well as whole-plant N uptake at maturity in our late-season supplemental N experiments (where pre-plant or standard sidedress of 75-80% of the intended N rate is followed by a late-stage V12-V14 sidedress application of the remaining 20-25% of total N). 

Project Results:

  • A data review found relationships between nitrogen efficiency terms and nitrous oxide emissions would be more discernable if published studies measured total nitrogen uptake in aboveground biomass and reported nitrogen recovery efficiency data.
  • The timing of nitrogen application affected the relationship between nitrogen recovery efficiency and nitrous oxide emissions, with a stronger relationship in treatments with side-dressed nitrogen applied at corn growth stages V6-8 and V14.
  • Nitrogen uptake is a better indicator of nitrous oxide emissions for systems applying nitrogen pre-plant.

Annual Reports

2015

2016

2018

Publications

Relationships of Nitrous Oxide Emissions to Fertilizer Nitrogen Recovery Efficiencies in Rain-fed and Irrigated Corn Production Systems: Data Review

Crops: Corn for grain
4R Practices: Metadata Project

Relationships of Nitrous Oxide Emissions to Fertilizer Nitrogen Recovery Efficiencies in Rain-fed and Irrigated Corn Production Systems: Data Review

Lead Researcher:

Dr. Tony Vyn

Department of Agronomy, Henry A. Wallace Chair in Crop Sciences

Purdue University

Start Date: 2014

End Date: 2015

Collaborating scientists and universities

  • Dr. Rex Omonode, Purdue University
  • Dr. Ardell Halvorson, USDA-ARS

Project Summary

Nitrous oxide (N2O) emissions from corn production systems are a large societal concern because so much of the N fertilizer applied to crop production in the United States is applied to corn, and because agriculture alone accounts for the majority of N2O emissions from all sources. The IPCC (2006) has estimated that an average of approximately 1.0% of the N fertilizer applied is lost as N2O, but we know from our own studies in rain-fed corn production that estimated emissions can sometimes exceed the equivalent of 5% of the N in the N fertilizers applied.

Over the years of scientific monitoring of N2O emissions, the predominant reporting method has been to quantify episodic and/or cumulative growing season N2O emissions per unit land area. Later refereed publications included acknowledgement of the importance of reporting yield scaled N2O emissions, but not until relatively recently has there been a plea to focus on emissions within the context of actual N use efficiencies. The recent meta-analysis by Decock (2014) highlighted the low proportion of past N2O emission studies that included critical information on treatment effects on crop N export (let alone any mention of crop N uptake).

The central hypothesis of this proposal is that increased corn plant N uptake (as a fraction of the fertilizer N applied) will be associated with reduced N2O emissions on area-scaled, yield-scaled, and NRE-scaled (i.e. plant N uptake per unit of N fertilizer initially applied) methods of interpreting relative N2O emissions from different management systems for corn production.

Project Goals:

  • Relate cumulative growing-season nitrous oxide (N2O) emissions to existing data on corn whole-plant N uptake (NU) and apparent nitrogen recovery efficiencies (NRE) in previous N2O emissions research in North America involving changing N management treatments (whether focused on N source, N rate, N timing and/or N placement) in both irrigated and rainfed corn production systems.
  • To illustrate the relationships between corn N uptake (apparent N recovery) and N2O emissions in different production environments and at different corn yield levels.

Project Results:

  • A data review found relationships between nitrogen efficiency terms and nitrous oxide emissions would be more discernable if published studies measured total nitrogen uptake in aboveground biomass and reported nitrogen recovery efficiency data.
  • The timing of nitrogen application affected the relationship between nitrogen recovery efficiency and nitrous oxide emissions, with a stronger relationship in treatments with side-dressed nitrogen applied at corn growth stages V6-8 and V14.
  • Nitrogen uptake is a better indicator of nitrous oxide emissions for systems applying nitrogen pre-plant.

Annual Reports

2015

2016

2018

Publications

Coordinated Site Network for Studying the Impacts of 4R Nutrient Management on Crop Production and Nutrient Loss

Crops: Corn for grain Corn for silage
4R Practices: Source Rate Time Place

Lead Researcher:

Dr. Matt Helmers

Professor

Iowa State University

Start Date: 2017

End Date: 2021

Collaborating scientists and universities

  • Dr. Sylvie Brouder, Professor Purdue University
  • Dr. Laura Christianson, Assistant Professor University of Illinois
  • Dr. Cameron Pittelkow, Assistant Professor, University of Illinois
  • Dr. Kelly Nelson, Professor University of Missouri
  • Dr. Dan Jaynes, Soil Scientist USDA-ARS National Laboratory for Agriculture and the Environment
  • Dr. John Kovar, Soil Scientist USDA-ARS National Laboratory for Agriculture and the Environment
  • Lowell Gentry, Research Scientist University of Illinois
  • Dr. Craig Drury, Research Scientist Agriculture and Agri-Food Canada
  • Dr. Fabian Fernandez, Assistant Professor University of Minnesota
  • Dr. Alison Eagle, Scientist, Sustainable Agriculture, Ecosystems Program, Environmental Defense Fund
  • Dr. Jeffrey Volenec, Professor Purdue University

Matching Funds

  • Foundation for Food and Agriculture Research

Project Summary

Currently, there is a concerted effort from industry, universities, and state and federal action agencies to promote the 4R nutrient management approach on-farm– considering the Right source, Right rate, Right time, and Right place– for managing nutrient additions from commercial fertilizer and organic materials. With its massive acreage and intensive nutrient use, corn production systems are an important focus of the 4R program. To convince farmers to adopt the 4R approach, and to ensure that production, soil health, and environmental goals are realized, there is a critical need for field research that measures responses to 4R management systems across a range of soils and agro-ecosystems within the main corn producing areas of North America. Limited research data linking agronomic and environmental performance of 4R practices across a wide variety of conditions is a critical research gap leading to high uncertainty regarding practice efficacy for both farmers and environmental program and policy decision makers. Along with production and soil health effects, full accounting of the multiple forms and pathways of nitrogen (N) and phosphorus (P) is essential to understand the environmental consequences of current and advanced best nutrient practices. A thorough accounting of the N balance could also serve as an early warning for practices that are improving or reducing soil carbon and thus soil health because soil carbon-nitrogen interactions dramatically impact soil organic matter accumulation and carbon sequestration. Further, potassium (K) nutrition of crops has attracted renewed attention, and although not of environmental concern, K requirements of crops are nearly the same as those of N, and cannot be ignored. We propose the creation of a coordinated field site network strategically distributed across the cornbelt with unique infrastructure that would collect similar agronomic and environmental measures thereby enabling for the first time knowledge synthesis across varied soils, climates, and management systems. Quantification of the impacts of 4R management on crop yield, P, K, and nitrate (NO3) losses in water, N losses to the atmosphere, and changes in soil health at the same location under a range of management practices is severely lacking. In addition, we are aware of no studies explicitly aimed at understanding the interactions between 4R management strategies and soil health.

Project Goals:

  • Quantify the impact of 4R Nutrient Stewardship on crop yield, soil health, nutrient use efficiencies, nutrient losses with leaching, and gaseous nitrogen losses across a network of coordinated studies in the major corn producing area of North America.

Project Results:

  • Preliminary nitrogen balance assessments indicated a -15 to -17 lb N/ac balance while optimizing corn yields when injecting N fertilizer for one study year averaged across all sites.
  • Corn-soybean rotations in the study resulted in a 10 to 24 lb N/ac lower nitrogen balance than a continuous corn system.
  • Conventional tillage resulted in greater corn yield with a reduced nitrogen balance of 4 to 7 lb N/ac compared to reduced tillage, however, the amount of nitrate loss in tile drainage was 9 to 13 lb N/ac greater with more intensive tillage.

Annual Reports

2017

Publications

Spatial and Temporal N Management for Irrigated Vegetable Production Systems

Crops: Apples Broccoli Cauliflower Celery Lettuce
4R Practices: Rate Time Place

Lead Researcher:

Dr. Charles Sanchez

Professor

University of Arizona

Start Date: 2019

End Date: 2022

Collaborating scientists and universities

  • Dr. Pedro Andrade-Sanchez, University of Arizona

Project Summary

Intensive vegetable production in the desert receives large annual applications of nitrogen (N) fertilizers. Soils in the southwestern United States are generally low in organic matter and amounts of N applied range from 200 to 400 kg/ha. Crop recoveries are less than 50%. There are numerous possible fates of fertilizer applied N in addition to the desired outcome of crop uptake. Over the past 15 years, researchers with the University of California and University of Arizona have developed strategies for efficient nutrient management. For N, these practices include fertilizer timing, pre-side dress plant and soil testing, and improved irrigation management. However, these guidelines have been applied to uniform management schemes in spite of the fact that fields often show considerable variation in soil properties. In-field soil textural variation is a significant factor affecting the mobility and availability of N. The prospect of variable rate (VRT) pre-plant and in-season N fertilizer application has not been evaluated in desert vegetable cropping systems. Certainly, varying N fertilizer applications by soil management zone makes sense. Further, emerging optical sensor technologies expand opportunities for in-season N management. We have evaluated VRT for pre-plant P fertilization in the desert. However, data exploring the potential for using VRT for N management is limited.

Studies conducted within Bard Water District, Yuma County Water Users Association, and Yuma Irrigation District in 2019-2020.

Project Goals:

  • Develop economically viable and effective sampling protocols to generate prescription maps for the variable rate pre-plant and in-season application of N comparing soil and plant sampling.
  • Compare variable rate N application to current methods and evaluate alternative economic outcomes.
  • Evaluate and test methods to augment zone-based management with optical sensors.

Project Results:

  • In the first year of this study, broccoli and iceberg lettuce yields were optimized with variable rate technology using soil-based zones.
  • Utilizing variable rate side-dress nitrogen applications, broccoli and iceberg lettuce yield per pound of nitrogen applied was optimized.

Annual Reports

Nitrate-sensitive salinity management: An advanced 4R practice to optimize nutrient and water uptake under microirrigation

Crops: Almonds
4R Practices: Time Place

Nitrate-sensitive salinity management: An advanced 4R practice to optimize nutrient and water uptake under microirrigation

Lead Researcher:

Dr. Patrick Brown

Professor

University of California-Davis

Start Date: 2019

End Date: 2024

Collaborating scientists and universities

  • Dr. Thomas Buckley, Assistant Professor, University of California-Davis

Matching Funds

  • Almond Board of California
  • CDFA-FREP
  • Netafim Irrigation
  • UC Agriculture and Natural Resources
  • Toro
  • Jain
  • Wilbur Ellis
  • Koch
  • Nutrien
  • American Farmland Trust

Project Summary

This study addresses a specific technical problem that the California almond industry is currently facing: How do you prevent nitrate leaching in micro-irrigated almonds orchards while simultaneously preventing salt accumulation in the root zone? Salinity imposes a significant impact in many areas of the central Valley of California and is greatly exacerbated in drought years when groundwater replaces surface water supplies. Californian agriculture is also now legislatively mandated to reduce nitrate leaching. Salinity has historically been managed by the application of water in excess of plant demand to leach salts (particularly Cl) below the active root-zone, NO3 however, leaches at essentially the same rate as Cl and hence will also move to the saline periphery of the root zone, where it is subject to loss. The control of salinity buildup by leaching, has not been optimized for the microirrigated context, and requires access to adequate water supplies and thus has a high potential risk of nitrate leaching and groundwater contamination. To develop irrigation and fertigation practices that achieve nitrate-sensitive salinity management, will require a deep understanding of root responses to micro-irrigation and the dynamics of nitrate and salinity uptake and movement in saline affected microirrigated orchards. To address this challenge, we propose an integrated study of root architecture and distribution, root physiology and plasticity, under micro-irrigation in almond. This study places a special focus on determining the ‘right place’ and ‘right time’ so that irrigation and fertigation strategies can be optimized to achieve nitrate-sensitive salinity management.

Project Goals:

  • To model/measure/validate patterns of root nitrate, water and salt uptake when roots are exposed to spatial and temporally heterogeneous conditions by the use of open-source tools (R and python among others) to characterize the structural and functional response of roots to micro-irrigation.
  • To model/measure/validate solute movement in the soil under different scenarios such as soil types, environmental conditions, irrigation frequency/length, and water qualities to characterize the environmental determinants of nitrate and salt movement.
  • To integrate modeling/validation processes that will be developed to improve our understanding of the ‘right place’ and ‘right time’ to achieve more accurate N-fertilization practices for almond orchards. This approach is applicable to all micro-irrigated tree crops in California, with relevance globally.

Project Results:

  • No preliminary results

Annual Reports

An Integrated Approach for Nitrogen Management In Upland Cotton Across The U.S. Cotton Belt

Crops: Cotton
4R Practices: Source Rate Time Place

An Integrated Approach for Nitrogen Management In Upland Cotton Across The U.S. Cotton Belt

Lead Researcher:

Dr. William Frame

Associate Professor

Virginia Tech

Start Date: 2019

End Date: 2023

Collaborating scientists and universities

  • Dr. Katie Lewis, Texas A&M University
  • Dr. Tyson Raper, University of Tennessee
  • Dr. Glendon Harris, University of Georgia
  • Dr. Ryan Stewart, Virginia Tech University

Matching Funds

  • USDA-NRCS
  • Koch Agronomic Services, LLC
  • Virginia Cotton Board

Project Summary

Nitrogen (N) is second only to water as a yield-limiting factor in non-legume cropping systems such as corn (Zea mays L.) and cotton (Gossypium hirsutum). Countless research endeavors have sought to unravel the dominant loss mechanisms/pathways in these two crops; however, the end result is that N use efficiency (NUE) remains ~33% worldwide and 40-60% in the U.S. As a result, roughly half to two-thirds of the applied N in non-legume cropping systems can move off-target and into the surrounding environment. To reduce these gaps in NUE, integrated research is needed to understand how N moves, transforms, and is utilized in non-legume cropping systems. This need is particularly urgent in cotton production systems, which represent 5.67 million hectares in the U.S. and required 373,409 metric tons of applied N in 2017.

Previous studies in cotton have focused on N application rates, timing, source, and placement (the 4R’s of nutrient management) in the Mid-South, Southeast, and Texas (High plains/Coastal Bend) regions of the U.S. In contrast, few studies have evaluated 4R’s of N management across the humid portions of the cotton belt, even though these areas represent 89.5% of production. At the same time, new/improved technologies and management strategies such as improved cotton varieties, enhanced efficiency fertilizers (EEF’s), and integrated cover crop solutions offer the potential to regulate N transformations in the soil and reduce N losses to surrounding ecosystems. Still, the ability of these techniques to improve NUE in contemporary cotton systems has not been rigorously examined. This project seeks to fill this important knowledge gap by integrating the 4R’s within a comprehensive agroecosystem perspective to improve NUE in cotton cropping systems, while also enhancing soil chemical and physical properties and decreasing off-target N movement via leaching and volatilization.

Project Goals:

  • Quantify the agronomic response of contemporary cotton varieties adapted to major production regions to varying N rates and placement strategies.
  • Determine the impact of EEF’s on N transformations and increasing NUE in cotton production systems.
  • Measure gaseous N losses, other common greenhouse gases from common N fertilizers, and leaching of N applied at varying N application rates and placements with and without enhanced efficiency N fertilizer additives or products.
  • Quantify the effectiveness of current N stabilizers and slow/controlled release N products on N transformations/species in representative soil types from the U.S. Cotton Belt in control laboratory environments.
  • Measure the impact of various cover crops and cropping rotations on N cycling and availability in different regional production systems and evaluate the responsiveness of cotton to applied N at those locations.
  • Develop a comprehensive management guide that informs regional management practices, thus reducing off target movement of N and maximizing the NUE of cotton systems.

Project Results:

  • No preliminary result

Annual Reports

Determine Benefits of 4R Nutrient Management and Conservation Practices On Water Quality and Use Efficiency via the Arkansas Discovery Farm Program: A Collective Learning Experience

Crops: Cotton Rice
4R Practices: Source Rate Time Place

Lead Researcher:

Dr. Andrew Sharpley

Distinguished Professor of Soils and Water Quality

University of Arkansas

Start Date: 2019

End Date: 2023

Collaborating scientists and universities

  • Dr. Mike Daniels, Cooperative Extension Service, University of Arkansas
  • Dr. Karl VanDevender, Cooperative Extension Service, University of Arkansas
  • Dr. Bill Robertson, Cooperative Extension Service, University of Arkansas
  • Dr. Nathan Slaton, Director Soil Testing Laboratory, University of Arkansas
  • Dr. Trenton Roberts, Crop, Soil and Environmental Sciences, University of Arkansas
  • Larry Berry, Discovery Farms Field Manager, University of Arkansas

Project Summary

Agriculture is the single largest economic sector in Arkansas, accounting for $21.4 billion of value added to the State’s economy in 2016 (University of Arkansas Division of Agriculture, 2019). Arkansas is the nation’s leading rice producer, second in poultry production and in the top 15 among states for cotton, soybean, and corn. Agricultural enterprise account for about 98% of the 1.1 million tons of fertilizer sold annually in Arkansas.

Nutrient enrichment remains a major impairment to the designated uses of fresh and coastal waters of the United States. While there are many sources of nutrients, the contribution of agriculture has received increased attention to reduce nutrient losses, fueled by recent modeling efforts and surveys, which suggest agriculture contributes up to 85% of the nutrients entering the Gulf of Mexico. However, there have been few farm-scale studies of the effects of nutrient management and conservation practice (CP) adoption on water use-efficiency, quality, and system sustainability under cotton and rice production in the Basin, particularly the Lower Mississippi River Basin. These concerns are manifested from regional issues such as hypoxia in the Gulf of Mexico and critical groundwater decline in lower Mississippi Alluvial Aquifer. Also, the cotton supply chain from field to gin, to mill, to retailer, wants assurances that cotton production is sustainable for future business interests. This has prompted supply chain groups such as Field to Market and the Cotton Leeds program, to measure and document indicators of sustainability. Several AR cotton producers are working with the University of Arkansas Division of Agriculture to use the Field Print Calculator for individual fields in AR. The Field to Market Field Print Calculator now includes metrics for rice and is being used by groups, such as the USA Rice Federation, to encourage producers to move towards more sustainable practices.

Project Goals:

  • This project will leverage and modify existing ADF monitoring to determine water quality and use benefits of 4R nutrient stewardship on three ADFs.
  • Collect and compile farm-nutrient management information and data for N, P, and K, along with other soil properties influencing soil fertility, such as pH, CEC, particle-size distribution, organic C, and the suite of Mehlich-3 extractable soil nutrients.
  • Collect soil and water samples, analyze, interpret, verify, and document nutrient and sediment loss reduction and water conservation.
  • Determine if the Field Print Calculator reliably expresses 4R effects plus conservation practices (CPs) on nutrient runoff potential.
  • Deliver an outreach and farmer – collective learning program that disseminates information to all stakeholders.