Tag: water quality

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Farm-System Modeling to Evaluate Environmental Losses, Profitability, and Best Management Practice Cost-Effectiveness

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Abstract

To meet Chesapeake Bay Total Maximum Daily Load requirements for agricultural pollution, conservation districts and farmers are tasked with implementing best management practices (BMPs) that reduce farm losses of nutrients and sediment. The importance of the agricultural industry to the regional economy highlights the need for determining cost-effective BMP solutions given the geographical and operational characteristics of these farms. This study evaluated both the environmental risk and farm profitability of common farm-level management practices for three major farm types in the region: crop, tractor-based (“English”) dairy, and horse-drawn (“Amish”) dairy.

Whole-farm simulations were conducted with the Integrated Farm System Model, a multi-year, process-based simulation model, to facilitate a broader understanding of the challenges for the farmers in finding financially feasible and environmentally sustainable solutions. Strip cropping, conservation tillage, cover cropping, and nutrient management BMPs generally reduced nutrient and sediments losses from all three farm types. However, scenarios that reduced phosphorus and sediment losses generally promoted more leaching of nitrogen. Double cropping corn with winter wheat combined with improved nutrient management was the most profitable practice for the crop farm, increasing average farm profitability by 92% over the baseline condition, while reducing combined nitrogen and total phosphorus losses by 13% and 23%, respectively.

Net profitability of the dairy farm was increased only by decreasing manure storage or using improved nutrient management. For the horse-drawn dairy, cover-cropping and harvest of rye silage combined with increased nutrient management provided the greatest increase in farm profit (+8%) and also reduced phosphorus and nitrogen losses.

Horse-drawn machinery through puts and increased human labor hours were required to simulate a typical Lancaster Old Order Amish dairy operation in Southeastern Pennsylvania.

Why Study Farms As a System?

Because southeastern Pennsylvania is a significant environmental contributor of the Chesapeake Bay, agricultural land management is under intense scrutiny by restoration groups. It is imperative to improving water quality that economically and culturally acceptable nonpoint source control practices be explored, developed, and evaluated. This is true for “contemporary” crop and dairy farms in the region as well as those that are more conservative in their use of electrical- or gas-powered farming equipment, described in this study as “Lancaster Old Order Amish”. Evaluation from a whole-farm perspective enables practical assessments of tradeoffs among management practice combinations and is particularly relevant when effectiveness relies on the willingness and dedication of the farm operators.

What Did We Do?

The expertise of regional conservationists and pooled results from farmer surveys were used to determine three major farm types in southeastern Pennsylvania and design potentially acceptable management combinations for each type. Three baseline farms were described: 400 ha corn-soy-wheat crop farm; 100 cow, 120 ha contemporary dairy; and 24 ha Lancaster Old Order Amish dairy. Whole-farm impacts were assessed with the Integrated Farm System Model (IFSM), a multi-year, process-based simulation model. Environmental tradeoffs between nitrogen, phosphorus, and sediment losses were evaluated and financial cost-benefits through change in annual net return for the farmer were analyzed.

What Have We Learned?

Strip cropping, conservation tillage, cover cropping, and improved nutrient management generally reduced nutrient and sediment losses from all three farm types. However, scenarios that reduced phosphorus and sediment runoff losses generally increased nitrogen leaching to groundwater. Double cropping corn and winter wheat under improved nutrient management was the most profitable combination for the crop farm, increasing average farm profitability by 92% over the baseline while reducing combined nitrogen and total phosphorus losses by 13% and 23%, respectively. Net profitability of the contemporary dairy farm was increased only by decreasing manure storage or using improved nutrient management. For the Lancaster Old Order Amish dairy, cover-cropping and harvest of rye silage combined with increased nutrient management provided the greatest increase in farm profit (+8%) and also reduced phosphorus and nitrogen losses.

Future Plans

Cost-effective recommendations from a whole farm perspective that account for unique characteristics of particular farm types can aid officials in determining locally agreeable methods for efficiently addressing regional priority pollutants. As farms adopt and implement suggested management changes, additional management practices of interest can be evaluated. Also, IFSM is being expanded to consider air emissions and carbon sequestration effects of the management practices.

Authors

Tamie L. Veith, Agricultural Engineer, USDA-ARS, tamie.veith@ars.usda.gov

Andrew D. McLean, Water Resources Designer, McCormick Taylor, Inc.

C. Alan Rotz, Agricultural Engineer, USDA-ARS

James M. Hamlett, Professor of Agricultural and Biological Engineering, The Pennsylvania State University

James S. Shortle, Distinguished Professor of Agricultural and Environmental Economics, The Pennsylvania State University

Additional Information

Integrated Farm System Model: http://www.ars.usda.gov/Main/docs.htm?docid=8519

McLean, A. D., 2012. Modeling best management practices on representative farms in Southeastern Pennsylvania. Master’s thesis, PA State University, University Park, PA. https://etda.libraries.psu.edu/paper/14093/, available Dec. 05, 2012.

Acknowledgements

This work contributes to the Conservation Effects Assessment Project (CEAP), jointly funded, coordinated, and administered by United States Department of Agriculture’s Natural Resources Conservation Service, Agricultural Research Service, and National Institute for Food and Agriculture. We would like to thank Mike Hubler and Larry Baum from Dauphin County Conservation District and officials at Lancaster and Lebanon County Conservation Districts for their advice and guidance categorizing and characterizing farms of Dauphin County and southeastern Pennsylvania. Thanks also to Kristen Saacke-Blunk and Matt Royer from Conewago Creek Collaborative Conservation Initiative for their time and input.  Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. USDA is an equal opportunity provider and employer.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

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Design of High Capacity, Energy Efficient Wells

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Abstract

Agriculture is the largest user of ground water in the United States.  Ground water at dairies is used for cow drinking, milking parlor clean-up and crop irrigation.  Ground water is produced from wells that often are improperly designed and completed. Inefficient well design, including improperly sized pumps, results in increased pumping costs and increases the frequency that wells and/or pumps have to be replaced.  Inefficient wells require significantly more energy to pump lesser amounts of water than properly designed wells.  Sand production from unconsolidated or poorly-consolidated aquifers reduces the effective life of the well and pump.  Sand production is significantly reduced by properly sizing the well screen and filter pack. Pilot holes are drilled so grain size analyses can be conducted and well screen and filter pack can be properly sized.  Geophysical logs may be utilized to identify zones of maximum potential production.  The pilot holes are reamed out to the design diameter and the well is constructed with an optimal screen and filter pack combination.  Efficient wells are designed with maximum open-area and proper filter packs, so well screens are not dewatered and the well does not pump sand or air.  Production tests on the completed well allow the pump motor and bowls to be sized and set to a depth that will maximize pump efficiency and water production while minimizing power costs.  An efficient, sand-free well will save a farmer significant money on energy costs to produce water, and the well and pump lifetime will be extended significantly.  Water wells should be designed carefully to maximize well and pump efficiency in order to conserve energy and not produce sand.

Purpose

To provide technical guidance on design development and completion of energy efficient wells to extend the operating life of wells and pumps.

What Did We Do?

We improved well efficiencies and reduced energy costs for pumping ground water.

What Have We Learned?

 To continue drilling, designing, developing and completing wells using techniques we have developed over the last 33 years. 

Future Plans

Continue to develop innovative methods for drilling wells.

Authors

Jay Lazarus, President, Glorieta Geoscience, Inc. lazarus@glorietageo.com

Jim Riesterer, Senior Geologist, Glorieta Geoscience, Inc.

Additional Information

http://www.glorietageo.com

Acknowledgements

Staff of Glorieta Geoscience, Inc.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

 

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Feed Management Planners Certification Program to Reduce Nutrient Loads in Impaired Watersheds

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Why Develop a Feed Management Certification Program?

To develop a program to train ARPAS-certified (American Registry of Professional Animal Scientists) dairy and beef nutritionists on how to prepare and evaluate Feed Management plans as it relates to the NRCS Feed Management (592) practice in Pennsylvania. The objective is to compare how formulated diets match to the consumed diets. Phosphorus is monitored through manure testing and nitrogen by milk urea nitrogen and calculating milk nitrogen efficiency. Dry matter intake efficiency is also monitored as this can affect the total manure volume excreted.

What Did We Do?

In 2007, Mid-Atlantic Water Program (MAWP) scientists applied the national feed management program to meet the needs of dairy consultants to implement feed management in the Chesapeake Basin. This program certifies consultants in precision feed management, a practice that reduces nutrient loads in animal wastes by minimizing the phosphorus and nitrogen content in the feed. 

With the recent release of the US Environmental Protection Agency’s Total Maximum Daily Load for the Chesapeake Bay, the agricultural community is looking for the best practices to control nutrient pollution while minimizing impacts to profit. Over the years, the work of this project team has established precision feed management as both an economically and environmentally viable best management practice.  As such, state watershed implementation plans include precision feed management as a method to meet load allocations.

Pennsylvania currently has twenty-four NRCS qualified nutritionists to write feed management plans. In 2011, fifty-one operations received EQIP or CBWI funding through USDA-NRCS for feed management, with the majority consisting of dairy farms.  An additional 10 farms entered into contracts with NRCS in 2012.  Farms are currently in the process of being assessed on how well they implemented recommendations from the first year of quarterly reports and are working through their second year of implementation.

Additional efforts have been implemented to educate consultants about the regulations and issues affecting dairy producers. Currently, the Pennsylvania team is working with producers to monitor income over feed costs and to develop cash flow plans, which provides the opportunity to implement precision feeding practices while monitoring the economic benefits to the herd.  A study of six component fed dairy herds in Pennsylvania is also being completed to evaluate the effects of the feed, forage, and manure sampling protocols along with feeding order on fecal phosphorus levels and to update current sampling recommendations.

Funding from the MAWP was critical to providing these trainings and projects and establishing precision feed management as a best management practice that farmers can realistically utilize.  The infrastructure is in place to address the demand for more feed management plans and the MAWP will continue to meet the educational needs of this audience.

What Have We Learned?

There are a lot of opportunities on farms to improve feed management and nutrient balance. Challenges have been observed pertaining to nutrient reduction strategies that could impact overall nutrient balances in dairy and beef rations. Many of these challenges are greatly influenced by the volatility in today’s commodity pricing. Producers need to become more engaged in what they are feeding and how it affects their profitability.  It has been observed that inorganic phosphorus is still being used in grain mixtures when rations contain high phosphorus forages or inclusion of byproduct feeds. We have also observed some challenges in obtaining test analyses for complete grain and mineral mixes on a regular basis.  More education is needed for both industry professionals as well as producers.

Future Plans

As the feed management program in Pennsylvania progresses, pounds of phosphorus excreted can be tracked to monitor the effects of reducing phosphorus in dairy and beef rations. This can be used to evaluate its effect on water quality and potential phosphorus accumulations in the soil when manure is applied to crops at nitrogen-based rates. Crop rotations, inclusion of alternative forages and whole farm nutrient balance will be included in future trainings and feed management plans. The Penn State Extension Dairy team is also working on the development of a Feed Management mobile app for producers and nutritionist to be able to track and monitor their progress on nutrient reductions in their rations.

Authors

Daniel Ludwig, Natural Resources Specialist, USDA – NRCS, dan.ludwig@pa.usda.gov

Virginia Ishler, Dairy Complex Manager/Nutrient Specialist, Penn State University

Rebecca White, Program Manager-Penn State Extension Dairy Team

Additional Information

Feed Management for Producers

Pennsylvania NRCS on Feed Management

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

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Swine Manure & Aqua-ammonia Nitrogen Application Timing on Subsurface Drainage Water

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Abstract

In Iowa and many other Midwestern states, excess water is removed artificially through subsurface drainage systems.  While these drainage systems are vital for crop production, nitrogen (N) added as manure or commercial fertilizer, or derived from soil organic matter, can be carried as nitrate-nitrogen (NO3-N) to downstream water bodies.  A five-year, five-replication, field study was conducted in north-central Iowa with the objective to determine the influence of seasonal N application as ammonia or liquid swine manure on flow-weighted NO3-N concentrations and losses in subsurface drainage water and crop yields in a corn-soybean rotation.  Four aqua-ammonia N treatments (150 or 225 lb-N/acre applied for corn in late fall or as an early season side-dress) and three manure treatments (200 lb-N/acre for corn in late fall or spring or 150 lb-N/acre  in the fall for both corn and soybean) were imposed on subsurface drained, continuous-flow-monitored plots. Four-year average flow-weighted NO3-N concentrations measured in drainage water were ranked: spring aqua-ammonia 225 (23 ppm) = fall manure 150 every year (23 ppm) > fall aqua-ammonia 225 (19ppm) = spring manure 200 (18 ppm) = fall manure 200 (17 ppm) > spring aqua-ammonia 150 (15 ppm) = fall aqua-ammonia 150 (14 ppm).  Corn yields were significantly greater (p=0.05) for the spring and fall manure-200 rates than for non-manure treatments. Soybean yields were significantly greater (p=0.05) for the treatments with a spring nitrogen application to the previous corn crop. Related: LPELC Manure Nutrient Management resources

Check Out These Other Presentations About Tile Drainage

Tile Drainage Field Day

Use of Filters in Drainage Control Structures

New Technologies for Drainage Water Management

Role of Drainage Depth and Intensity on Nutrient Loss

Why Study Sub-Surface Drainage and Manure Application?

Subsurface agricultural drainage has allowed for enhanced crop production in many areas of the world including the upper Midwest, United States. However, the presence of nitrate-nitrogen (nitrate-N) in subsurface tile drainage water is a topic of intense scrutiny due to several water quality issues. With the growing concern for the health of the Gulf of Mexico and local water quality concerns, there is a need to understand how recommended nitrogen management practices, such as through nitrogen rate and timing, impact nitrate-N concentrations from subsurface drainage systems.  The objective of this presentation is to summarize results of studies from Iowa that have documented the impact of nitrogen application rate and timing on tile drainage nitrate loss. 

What Did We Do?

The field experimental site was located near Gilmore City in Pocahontas County, IA. In the fall of 1999, seven treatments were initiated on 35 plots at the site to determine the effect of N source, rate, and application timing on crop yield and subsurface drainage water quality in a corn and soybean (CS) rotation. Two fertilizer N rates (168 or 252 kg ha-1) applied in the spring or fall and liquid swine manure (LSM) applied in spring or fall (218 kg ha-1) for corn production, and fall applied LSM for both crops in a CS rotation (168 kg ha-1) were randomly distributed in five blocks. Flow-weighted drainage samples were collected and volume measurements recorded for each plot through sampling/monitoring systems during drainage seasons in 2001-2004.

What Have We Learned?

This multi-year experiment demonstrated that rate and to a lesser extent timing affect concentration and losses and even at constant rates, these can be highly variable depending on precipitation patterns, N mineralization/denitrification processes and crop utilization in a given season. As expected, as nitrogen application rate to corn increases, the nitrate-N concentrations in subsurface tile drainage water increase.  This highlights the need for appropriate nitrogen application to corn and to avoid over application.  However, it is important to note that even when recommended nitrogen application rates are used, nitrate-N concentrations in subsurface drainage are still elevated and may exceed the EPA drinking water standard for nitrate-N of 10 mg L-1.  Relative to timing of nitrogen application, i.e. moving from fall to spring application, our studies showed little to moderate potential to decrease nitrate-N concentrations. Likely the largest factor when looking at the effect from fertilizer application timing is when precipitation and associated nitrate-N loss occurs.  Although timing of nitrogen application is important, perhaps the most important factor is to apply the correct amount of N. Manure treatments out yielded commercial N in all years. No significant differences in corn yield for any year were noted between application timing. Soybean yields were affected by N timing and less so by application rate.
click on image to enlarge

Future Plans

Other management practices need to be explored for their potentials in reducing nitrate loads from tile drained systems. Promising practices include drainage management, alternative cropping systems and edge-of-field practices.

Authors

Matthew Helmers, Associate Professor, Department of Agricultural & Biosystems Engineering, Iowa State University, mhelmers@iastate.edu

Xiaobo Zhou, Assistant Scientist, Department of Agricultural & Biosystems Engineering, Iowa State Univeristy

Carl Pederson, Agricultural Specialist, Department of Agricultural & Biosystems Engineering, Iowa State University

Additional Information

Lawlor, P.A., A.J. Helmers, J.L. Baker, S.W. Melvin, and D.W. Lemke. 2011. Comparison of liquid swine manure and ammonia nitrogen dynamics for a corn-soybean crop system. Trans. ASABE 54(5): 1575-1588.

LPELC Manure Nutrient Management home

Acknowledgements

Funding for this project was provided by the Iowa Department of Agriculture and Land Stewardship through the Agricultural Water Management fund.

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

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What Practices are Reducing Environmental and Economic Risks on Wisconsin Farms?

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Abstract

This workshop will focus on how dairy farmers in Wisconsin evaluate the risk of nutrient and sediment loss on their operations and what best management practices are adopted to reduce these risks.  Dennis will describe how farm families evaluate all the risk factors facing their operation (weather, production, marketing, labor, safety and environmental risks) and discuss how a farmer has to balance the risk and rewards for each of these challenges.  It is helpful to gain an appreciation for the numerous challenges farmers face on a daily basis and the amount of time committed to the evaluation and implementation of soil and water best management practices on each farm. Conservation practices are often applied in a “one size fits all” approach and are not developed and implemented to fit the needs of each farming operation.  The large diversity of both farming systems and physical settings require a collaborative evaluation and implementation process between producers and conservation technicians to develop economic, effective, and practical conservation practices to fit the specific circumstances of individual farming operations.

What Are Some of the Lessons Learned in Managing Environmental Risks?

The focus of this talk is to explain when and where we saw nutrient and sediment losses that could have been avoided with improvements in management.  We will also discuss what we have learned about unavoidable losses and try and explain the difference between unacceptable risk and acceptable risk.

What Did We Do?

Over the past twelve years UW – Discovery Farms has worked on many farms evaluating a variety of farming systems and identifying the positive and negative impacts that production agriculture can have on the environment.  Data collection through this program includes over 120 sites years of edge-of-field monitoring, in-stream monitoring and monitoring tile drainage systems.  All the monitoring was done in partnership with the United States Geological Survey (USGS)  and this data set is one of the largest and best on-farm sets known to exist.

What Have We Learned?

Discovery Farms has studied a variety of farming systems including no-till, minimal tillage, tillage and rotational grazing.  The settings for these farming systems ranged from very steep (the driftless region with slopes up to 32%) to gently rolling (<3%) with a variety of unique challenges including manure management, tile drainage systems and close distance to surface water.  On each of the operations that were studied, the farm operators have selected a farming system (tillage, planting, pest control, manure management, harvest, crop rotation, etc) that works for them.  For the first two years of the study we asked the producers not make changes to their farming systems so that we could evaluate nutrient and sediment loss from their current practices.  It quickly became apparent that on real farms, nothing stays the same.  All of our cooperators made adjustments in management based not only on the data we were collecting, but also based on economics, changes in demand and changes on the operation (equipment, land base, labor, increase in cattle numbers).  It is also apparent that even with the best farming system, implemented almost perfectly; mother nature can throw some unanticipated events which have a tremendous impact on nutrient and sediment losses. 

Future Plans

In 2010, the UW – Discovery Farms Program expanded their on-farm research program to include not only edge-of-field and in-stream work on individual farms;  they are now working with multiple farms in small watersheds.  The goal of these studies is to better understand the relationsihp betweeen edge-of-field losses and what actually happens in lakes and streams.

Authors

Dennis R. Frame, Director, UW – Discovery Farms Program; Professor UW – Extension,  drframe@wisc.edu

Amber Radatz, Outreach Specialilst, UW – Discovery Farms

Eric Cooley, Outreach Specialist, UW-Discovery Farms

Additional Information

UW Discovery Farms makes every effort to develop materials from all of the on-farm research projects.  These materails are available on our website (uwdiscoveryfarms.org or by contacting our office at 1-715-983-5668).

Acknowledgements

The authors would like to thank all the farmers who have participated in our program.  Without their guidance and support this program would not be possible.  We would also like to acknowledge the support and guidance of all the non-governmental agricultural organizations in Wisconsin who continue to provide support financially and politically.

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

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Playing By the Rules: Regulations and Animal Agriculture

This is a self-guided learning lesson about air and water regulations related to livestock and poultry production. Anticipated time for completion: 60 minutes. At the end is a quiz that can be submitted for a certificate of completion. Teachers/educators should check out the accompanying instructional materials.

This lesson includes 3 sections:

  1. Water quality regulations, including the Clean Water Act (CWA)
  2. Air quality regulations
  3. Record keeping and its importance to regulatory compliance

Sections 1 and 2 include resources on the relationship between federal, state, and local authorities.

1. Water Quality Regulations, Including the Clean Water Act

Watch this 20 minute video presented by Thomas Bass, Montana State University.

Recommended Reading

Federal Water Quality Regulations

2. Air Quality Regulations

Read the following publication “Air Quality Regulations in Animal Agriculture: An Introduction” (4 pages; PDF)

3. Record Keeping and Regulatory Compliance

Records protect producers and document that they are doing the right thing. Watch these four short videos that include viewpoints of regulators and farmers about the importance of records.

Why Are Animal Operations Inspected?

Why Should We Keep Records?

What Happens During an Inspection?

What Happens After an Inspection?

Recommended Reading

Record Keeping and Inspections for Animal Feeding Operations (web page)

Quiz

When you have completed the above activities, take this quiz. If you score at least 7 of 10 correct, you will receive a certificate of completion via email. If you are a member of an organization that requires continuing education units (CEUs), we recommend that you submit your certificate to them for consideration as a self-study credit. American Registry of Professional Animal Scientist (ARPAS) members can self-report their completion of this module at the ARPAS website.

Acknowledgements

Author: Thomas Bass, Montana State University tmbass@montana.edu

Building Environmental Leaders in Animal Agriculture (BELAA) is a collaborative effort of the National Young Farmers Educational Association, University of Nebraska-Lincoln, and Montana State University. It was funded by the USDA National Institute for Food and Agriculture (NIFA) under award #2009-49400-05871. This project would not be possible without the Livestock and Poultry Environmental Learning Center and the National eXtension Initiative.

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Environmental Impacts and Benefits of Manure: Phosphorous and Surface Water Protection

Managing manure nutrients in an environmentally and economically responsible manner is not a mutually exclusive endeavor. This article discusses phosphorus and its potential impacts on water quality.

Phosphorus and Water Quality

Phosphorous (P) is one of the major bio-available nutrients in manure. In aquatic ecosystems, P is typically the most limiting nutrient. When P is introduced into an aquatic ecosystem there is a marked increase in aquatic plant biomass production and increased algal blooms. The increased aquatic plant production and algal blooms can have a negative effect on the aquatic ecosystem such as tying up other nutrients and decreasing the amount of light infiltration.

At the end of the aquatic plant and algae growing cycles, there is a large release of excess nutrients into the ecosystem overwhelming the natural nutrient cycle, tying up oxygen during its degradation leading to fish kills and reducing surface water aesthetic qualities with the accumulation of rotting plant material on the water surface and offensive odors.

How Does Phosphorus Travel to Water?

In cropping systems, providing a sufficient level of P for plant uptake is as important as providing the proper levels of nitrogen (N) and potassium (K). Unlike N and K, P is bound to soil particles and is at low risk of leaching through the soil profile. The greatest risk of P loss from soils is with overland flow of runoff carrying P-enriched soil sediment or manure particles. Research has shown that soils testing high in P have a greater contribution effect for P loss than soils testing low in P.

However, there is a fraction of total P in runoff that is in the dissolved form. The sediment attached P and dissolved P have slightly different impacts in aquatic ecosystems. The sediment attached P contributes to long term P additions to the system whereas the dissolved P is readily available for a high rate of assimilation by aquatic plants and algae.

There are also reported cases of soils with extremely high levels of soil test P that are at risk of P leaching. Typically, soil P is bound tightly to soil particles and has a low risk of leaching. However, in some soils with extremely high soil test P levels, the exchange sites are at maximum capacity, leading to the risk of P leaching.

Blue-green algae bloom in nutrient impaired water. Source: Ron Wiederholt, NDSU Extension

 

Management Practices to Reduce Environmental Risks from Phosphorus

Cropping system practices that lead to reduced soil erosion are the most effective means of decreasing the risk of off-site movement of P. Besides soil erosion, there are other factors that need to be identified when reducing the risk of P loss from fields.

These factors include but are not limited to:

  • distance to surface water
  • slope of the landscape
  • soil erosivity index
  • soil test P level

Many states have adopted a process of ranking the risk of P loss from agricultural fields using a P-index. The USDA Natural Resources Conservation Service (NRCS) has been the lead agency in developing most of the state-by-state P-indexes. A P-index scores the factors important for off-site movement of P and by using the combined score of these factors a land manager can decide what options are best for managing P application levels to fields when using manure or commercial fertilizer.

However, the use of a P-index is only one of the tools available to nutrient managers. When there has been a long history of P mis-management and soil test P levels are extremely high, a P-index or other tools are not as effective. In these cases, a long term approach looking at the whole cropping and livestock system needs to be adopted.

Livestock rations must be closely monitored to ensure there is no P overfeeding (see the LPELC topic, Feed Management), manure may have to be sold or bartered to other land managers, or some type of intensive manure processing system will have to be adopted that will allow for more affordable long distance hauling of the manure (see the LPE Learning Center topic Manure Treatment Technology).

Recommended Reading On Phosphorus and Surface Water

Page Managers: Ron Wiederholt, North Dakota State University and Marsha Mathews, University of California-Davis

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Minnesota Watershed Nitrogen Reduction Planning Tool

Abstract

Using the nitrogen reduction planning model involves three steps.  The first step is to select a watershed, enter hypothetical adoption rates for each BMP, and compare the effectiveness and cost of the individual BMPs.  The second step is to compare suites of the BMPs that would attain any given reduction in the N load at minimum cost.  The third step is to “drill down” to the details and assumptions behind the models of effectiveness and costs of any particular BMP and make any adjustments to reflect your particular situation.

Why Develop a Nitrogen Reduction Planning Tool?

A watershed-level nitrogen reduction planning tool (Excel spreadsheet) compares the effectiveness and cost of nine different “best management practices” (BMPs), alone and in combination, for reducing N loads leaving a Minnesota watershed.  The Minnesota Pollution Control Agency is developing a new set of standards for nitrate nitrogen in surface waters based on aquatic life toxicity.  The tool was developed to assist the agency and local resource managers to better understand the feasibility and cost of various “best management practices” to reduce N loading from Minnesota cropland.

What Did We Do?

The BMPs are:  reducing corn N fertilizer rates to extension recommended rates, changing fertilizer application timing, seeding cover crops, installing tile line bioreactors or controlled drainage, planting riparian buffers, or converting some corn and soybean acres to a perennial crop. The spreadsheet does its analysis for a watershed that the user selects.  However, the N loadings and crop economic calculations are done first by agroecoregion before aggregating the results into the watershed of interest.  Agroecoregions are units having relatively homogeneous climate, soil and landscapes, and land use/land cover.  The spreadsheet includes area data for the fifteen high-N HUC8 watersheds that make up roughly the southern half of the state, along with the state as a whole.  When the user selects a watershed for analysis, formulas retrieve results as an area-weighted average of the agroecoregions making up that watershed.  Each of the fifteen HUC8 watersheds includes between four and nine agroecoregions.

The N loadings from each agroecoregion are calculated in three categories:  drainage tile discharges, leaching from cropland, and runoff.  Nitrogen loading amounts modeled are “edge-of-field” measures that do not account for denitrification losses that occur beyond the edge of field as groundwater travels towards and is discharged to streams.  The BMPs consider only loading from cropland, but loading from forests and impervious urban and suburban land is also included in the totals.

What Have We Learned?

The EPA’s Science Advisory Board has said that a 45% reduction in both N and P is needed in the Mississippi River to reduce the size of the Gulf of Mexico hypoxic zone.  This tool suggests that the BMPs considered are not likely to achieve much more than half that reduction even at high adoption rates.  Reducing N fertilizer rates on corn down to extension-recommended levels and shifting from fall to spring or sidedressed applications tend to be among the cheaper BMPs to adopt, but the results vary across watersheds and weather scenarios.  Various other factors such as crop and fertilizer prices also affect the results, hence the need for a computer tool.

Future Plans

The tool and results of a larger project will be reviewed during the first half of 2013.  The tool may then play a role in implementation of the new N state standards in the state.

Authors

William F. Lazarus, Professor and Extension Economist, University of Minnesota wlazarus@umn.edu

Geoff Kramer, Research Fellow, Department of Biosystems and Bioproducts Engineering, University of Minnesota

David J. Mulla, Professor, Department of Soil, Water, and Climate, University of Minnesota

David Wall, Senior Hydrologist, Watershed Division, Minnesota Pollution Control Agency

Additional Information

The latest version of the tool and an overview paper are available at the author’s project page.

Davenport, M. A., and B. Olson. “Nitrogen Use and Determinants of Best Management Practices:  A Study of Rush River and Elm Creek Agricultural Producers Final Report, submitted to the Minnesota Pollution Control Agency  as part of a comprehensive report on nitrogen in Minnesota Surface Waters.” Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, September 2012.

Fabrizzi, K., and D. Mulla. “Effectiveness of Best Management Practices for Reductions in Nitrate Losses to Surface Waters In Midwestern U.S. Agriculture.  Report submitted to the Minnesota Pollution Control Agency  as part of a comprehensive report on nitrogen in Minnesota Surface Waters.” September 2012.

Lazarus, W. F., et al. “Watershed Nitrogen Reduction Planning Tool (NBMP.xlsm) for Comparing the Economics of Practices to Reduce Watershed Nitrogen Loads.” December 11, 2012, http://wlazarus.cfans.umn.edu/.

Mulla, D. J., et al. “Nonpoint Source Nitrogen Loading, Sources and Pathways for Minnesota Surface Waters.  Report submitted to the Minnesota Pollution Control Agency  as part of a comprehensive report on nitrogen in Minnesota Surface Waters.” Department of Soil, Water & Climate, University of Minnesota, September 2012.

Acknowledgements

Partial support for this project was provided by the Minnesota Legislature.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

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Spreading Manure In Winter. What Are the Risks?

This archive was recorded from a live presentation at the 2011 North American Manure Expo. Kevan Klingberg, University of Wisconsin Discovery Farms discusses how application of manure nutrients on frozen and snow-covered soils became such a hot issue. He also explains their research program that monitors surface water quality on commercial farms.  Lastly, he discusses the results of the research and how that information is being used to make management decisions on farms.  Note: The recording volume was set high on these segments. Start with your speaker volume on low and move it louder if needed.  Originally broadcast July 20, 2011. Continue reading “Spreading Manure In Winter. What Are the Risks?”

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