Tag: nutrient loading

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Assessing the implications of chloride from land application of manure for Minnesota waterways

Purpose

Rising chloride contamination in ground and surface waters is a growing concern in Minnesota. Previous studies estimate 87% of the chloride load originated from road salts, fertilizers, and wastewater treatments plants, and 6% from livestock manure. However, these estimates may be outdated as the livestock industry and manure application practices have evolved since these estimates of manure chloride concentrations were calculated in 2004. It also remains unclear how varying soil types affect the movement of chloride leaching following manure application. The aim of this study is to understand the movement of manure-based chloride from liquid and solid manures in Minnesota soils through a series of intact core leaching studies. Specifically, this project examines the magnitude of chloride leaching from swine and turkey manure application and compares it with synthetic potassium chloride fertilizer and a no nutrient control. The soil cores represent fine and medium textured soil.

What Did We Do?

    • Collected 24 12-inch soil columns from medium and fine-textured soils in Minnesota (Figure 1).
    • Collected swine and turkey manure from Minnesota farms
    • Analyzed soil pre- and post-leaching study for nutrient analysis (Cl−, Bray P, NH4+, NO3−, K, Organic Matter, pH, and Exchangeable Ca, Mg, Na, K)
    • Analyzed manure samples for nutrient analysis pre-application (Total N, P2O5, K2O, Cl−)
    • Added water to cores until they reached field capacity
    • Applied manure using N-based application rates, and fertilizer using a K-based rate to 3 replicates
    • Simulated 2-in rainfall events on days 4, 12, and 18 post nutrient application
    • Collected and analyzed leachate for Cl−, NH4+-N, and NO3−-N
Figure 1: Setup of 12-inch PVC soil cores for leaching study

What Have We Learned?

    • How chloride concentration varies based on manure type and species
    • How the total amount of chloride applied via fertilizer application to cores varies by treatment
    • How manure-based chloride moves through soil
    • How fine and medium textured soil influences the movement of manure-based chloride
    • How chloride storage changed by soil type following the experiment (Figure 2)
      1. Medium textured soils had a greater change in chloride storage in both top and bottom layers compared to fine textured soils
      2. Manure additions increased chloride storage in both medium and fine textured soils
      3. Control soil cores experienced a loss in chloride storage following leaching
Figure 2: Change in soil chloride storage in each medium textured (left) and fine textured (right) soils by treatment. Positive values indicate a net gain in soil chloride, while negative values indicate a net loss in soil chloride following leaching.
Table 1: Total Cl− concentration of liquid swine manure (lbs/1000 gallons), solid turkey litter, and synthetic KCl (lbs/ton) followed by total weight (g) of Cl− added per core via application.
Treatment

Cl− (lbs/1000 gallons)

Cl− (lbs/ton)

Cl− added per core (g)
Liquid

26

–

1.49
Solid

–

2.7

0.179
KCl

–

940

0.576
Control

–

0

0

Future Plans

Our group would like to complete a second round of this study the following year on newly identified liquid and solid manure and an additional coarse textured soil type. Future attempts in creating chloride-based mass balances for the state of Minnesota will benefit from this study.

Authors

Matthew Belanger, Graduate Research Assistant, Dept of Soil, Water, and Climate, University of Minnesota

Corresponding author email address

belan081@umn.edu

Additional authors

Dr. Erin L. Cortus, Associate Professor and Extension Engineer, Dept of Bioproducts and Biosystems Engineering, University of Minnesota

Dr. Gary W. Feyereisen, Research Agricultural Engineer, USDA-ARS Soil & Water Mgt. Research Unit

Nancy Bohl Bormann, Graduate Research Assistant, Dept of Soil, Water, and Climate University of Minnesota

Dr. Melissa L. Wilson, Assistant Professor and Extension Specialist, Dept of Soil, Water, and Climate, University of Minnesota

Additional Information

Wilson Manure Management and Water Quality Lab Site

Acknowledgements

This project is funded through the University of Minnesota Water Resource Center’s Watershed Innovation Grants Program. We’d also like to thank Scott Cortus, Eddie Alto, Todd Schumacher, Dr. Pedro Urriola, and Thor Sellie for their assistance.

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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.

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