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Reducing Nutrients Through Conservation: A Paired Watershed Study

Ashleigh Hammac

Master of Research in Soil Science Defense

07/31/2014

North Carolina State University

Soil Science Department

Outline Introduction Objective Methods & Materials Results Conclusions Acknowledgements Questions

IntroductionImportance of Study

Increase in Eutrophicationo Eutrophication: a natural process of water bodies

becoming more enriched and productive through an increase in nutrient supply (Smith et al, 1998)

o Algal Blooms • CyanoHABs

Smith et al, 1998

Why is it important to reduce nutrients? Eutrophic Conditions for Water

ResourcesFreshwater lakes 0.065-0.12 mg TN L-1

0.003 mg TP L-1

Streams >0.03 mg TN L-1

0.075 mg TP L-1

Marine >0.04 mg TN L-1

Teaching Great Lake Science Australian dinoflagellates Red Tide

Algal Blooms and CyanoHABs

IntroductionImportance of Study

Increase in Eutrophicationo Algal Blooms

• CyanoHABs Human Health

o Nitrate-Nitrogen(NO3-N) concentrations• >10mg NO3-N L-1 drinking water EPA limitations• Methameblogmeia (blue baby syndrome)

What degrades water quality???

IntroductionImportance of Study: North Carolina

North Carolina Division of Water Quality determined that non-point sources of pollution such as agriculture to be the single largest contributor of nutrients to the Neuse River and Cape Fear River Basins (NCDWQ 1996)

http://www.learnnc.org/lp/editions/nchist-recent/6202

IntroductionImportance of Study: North Carolina

Point and Non-point Source Pollution

o Point Source: delivered directly from discrete conveyance such as waste water treatment plants, industrial facilities or direct dumping of waste into streams. Point source pollutants are federally regulated.

o Non-point Source: diffuse sources that do not have a discernable direct source and are normally moved through the system by runoff

• Includes oils, sediments, animal wastes, fertilizers, herbicides, insecticides (EPA, 1998a)• Less regulated.

IntroductionImportance of Study: Jordan

Lake The Jordan Lake Watershed has

pressures to decrease the amount of sediment and nutrients in it’s bodies of watero Environmental Management

Commission: 1983 it placed Jordan Lake Reservoir on a Nutrient Sensitive Water

• Ordered limits on phosphorus wastewater discharge

• Saw no response to controls Additional regulations imposed in

January 2008 that affected point and non-point (urban and ag) sources of nutrients.

Greensboro

Chapel Hill

Durham

Burlington

Jordan Lake

Reidsville

Map Produced: R. Austin, D.Osmond

²

Jordan Lake Watershed

0 10 205 Miles

Cape Fear River Basin

North Caro lina State UniversityDepartment of Soil Science

North Carolina Stateplane, Zone 4901, NAD83 meters

Introduction Nutrient Load Reductions

required by the state of North Carolina from the 1997-2001 baseline periodo Haw Sub Basin:

• 8% Nitrogen and 5% Phosphoruso Upper New Hope Sub Basin:

• 35% Nitrogen and 5% Phosphorus

o Lower New Hope Sub Basin: • 0% Nitrogen and 0%

Phosphorus

Slide credit: Dr. Osmond, NCSU

Objective

To quantify the effectiveness of agricultural conservation practices, such as livestock exclusion and nutrient management, on surface water quality in the Jordan Lake watershed of North Carolina

Materials and MethodsOverview

Water Quality Monitoring:o Automated runoff samplerso Precipitation data

Land Use Monitoringo Farmer surveys

Paired Watershed Design

Materials and Methods: Water Quality Monitoring

Monitoring Stations:o Automated Sampler

• ISCO 6700 and 6720• Integrated flow meter

o Permanent staff gauge• Stage-discharge relationships measured and adjusted

periodically.o Tipping bucket rain gauge

• 15 minute basis

Control CroplandCredit: Wesley Childres

Treatment PastureCredit: Wesley Childres

Control PastureCredit: Wesley Childres

Treatment PastureCredit: Wesley Childres

Methods and Materials: Water Quality Monitoring

Storm Event Samples Continuous Rainfall Grab Samples*

Chemical AnalysisKjeldahl Nitrogen (TKN)

Ammonium Nitrogen (NH4-N)

Nitrate + Nitrite Nitrogen (NOx-N)

Total Phosphorus (TP)

Dissolved Phosphorus (DP)*

Bacteria (E. coli)*

Total Suspended Solids (TSS)

Materials and Methods: Sampling Procedures

Storm Event Sampling: bi-weekly (2 week intervals)o 125-150mL sample for TKN, NH4-N, NOx-N, and TP

• Acidifiedo 250-500mL sample for TSS

• Non acidified

Grab Samples: seasonalStorm samples are acquired within 12 hours of a storm eventBase flow sampleso Analyze for:

• Bacteria (e-Coli)• Dissolved Phosphorus• Analyzed within 6-8 hours

Materials and MethodsOverview

Water Quality Monitoring:o Automated runoff samplerso Precipitation data

Land Use Monitoringo Farmer surveys

Paired Watershed Design

Materials and Methods: Additional Monitoring

Land use monitoring:o Collected annually through farmer surveys

• Crop(s)• Planting and harvest dates

• Fertilizer application(s)• Method• Type• Amount• Placement

• Animal stocking density• Diet additives

o Bi-weekly field survey• Record visible land uses, animal stocking densities at time

of sampling.

Materials and MethodsOverview

Water Quality Monitoring:o Automated runoff samplerso Precipitation data

Land Use Monitoringo Farmer surveys

Paired Watershed Design

Materials and Methods: Paired Watershed Design

DefinitionComparisons of adjacent sub watersheds with similar land uses in two temporal periods:

o Pre-BMP: Before conservation practices• No changes made to the land use practices• 2-3 years of monitoring• All watersheds monitored simultaneously

o Post-BMP: After conservation practices• 2-5 years of monitoring• 1 out of at least 2 watersheds have BMPs implemented

Materials and Methods: Paired Watershed Design

Why use paired watershed design?o Addresses the dynamic system interactions

o Non-biased; aka no “assumptions” of how the system interacts

o Variability of weather isn’t optimal but occurs.• Consistent data for “typical” weather is acquired

over a long pre and post-BMP period

Materials and Methods: Control vs. Treatment

The determination of which sub-watersheds are the Control vs. Treatment is mostly up to farmer

cooperation

Pasture (L)

Pasture (M)

Control and Treatment for Pastures

Crop (V)

Crop (R)

Control and Treatment Croplands

Pasture “Pair”

Crop“Pair”

Methods and Materials: Paired Watershed Design

The Jordan Lake Paired Watershed Study

Stages of Water Quality Monitoring:

o Pre-BMP • Crop and Pasture: Start of 2008

o Post-BMP• Pasture: Spring 2011 (Fertilization) and Fall 2011 (Exclusion

Fencing)• Crop: Fall 2012

Began work at NCSU (Fall 2012)

Materials and Methods: Control Pasture (L)

• 193 ac, 40% beef and dairy pasture

• Aquic Hapludult (<6% slope)• Soil Test M3P 166 mg kg-1

Multiple Land Uses

Materials & Methods: Control Pasture (L)

Cropland and Hayland Pre-Treatment (2008-2010)

o Cropland: • Corn 22.1 acres (11.5%)

• 2010• 17-17-17, 336 kg ha-1

• (300 lb ac-1)

• 85 lb N ac-1 sidedress• Harvest mid August• Ripped/disked in 2010• Fallow 2008-2009

o Hayland:• Hay 16.2 ac (8.4%)• 2.5 tons ac-1, 2-3 times per year• Fertilized with Pullet Manure

• 3 tons ac-1

Post-Treatment (2011-2013)

o Cropland:• Soybean 22.1 acres (11.5%)

• 2013• 17-17-17, 336 kg ha-1

• (300 lb ac-1)

• 85 lb N ac-1 sidedress• Harvest mid November.• Fallow 2011-2012

o Hayland:• Hay 16.2 ac (8.4%)• 2.5 tons ac-1, 2-3 times per year• Fertilized with Pullet Manure

• 3 tons ac-1

Materials & Methods: Control Pasture (L)Pastures and Forest

Pre-Treatment (2008-2010)

Pasture72.7 ac (37.7%)

o Dairy and Beef Cow• Near 100 cows total • Even mix of dairy and beef

cows.o Fed with Additives

• Fed with hay in winter: 12% protein additive and High Mag block.

Forest 61.3 ac (31.8%)

Post-Treatment (2011-2013)

Pasture72.7 ac (37.7%)

o Beef Cow• Near 80 cows total• Mostly beef cows.

o Fed with Additives• Fed with hay in winter: 12% protein

additive and High Mag block.

Forest 61.3 ac (31.8%)

• ≈ 5 ac cut in 2013.

Pasture Control (L)

Crop

Pasture

Station

Hay

M: Treatment Pasture (M)

• 134 ac, 90% beef pasture• Aquic Hapludult (3-6%)• Soil test M3P 118-1060 mg kg-1

Materials and Methods: Treatment Pasture (M)

Pre-Treatment Land Use:2008-2010

Fertilizer: o 15-15-15 at 336 kg ha-1

• (300 lb ac-1) o Biosolids applied in April 2010

Crop: fescue for cattle

Uses additives.

Rotates cows in fields.

Post-Treatment Land Use:2011-2013

Nutrient Management in 2011, 2012, and 2013. o STP very high (range)o Nitrogen fertilizer

• Under applied at 78 kg ha-1 • (70 lb N ac-1)

Livestock Exclusion by fencingo Installed in 2011.

Continued field rotations.

Livestock average:

26 adult cow26 calves

Station

Pasture

Pasture Treatment(M)

Results Data interpretations in preliminary stage!

o 1st - 3rd years of Post Treatment installation monitoring• Pastures only

o End: March 2014 • (data collection not finished)

Analysis done only for Pasture Pairo Pre and Post Treatment data for pastures only

Pasture Paired Watershed: Hydrology Comparison

Paired Watershed studies rely on a significant hydrologic relationship.

Statistical comparison of chemical constituents is reasonable.

0 1,000,000 2,000,000 3,000,000 4,000,000 5,000,000 6,000,0000

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

f(x) = 0.952024273476317 x + 10524.8510678421R² = 0.737398906871159

f(x) = 1.04559498241859 x + 95322.1462332817R² = 0.871061792838042

Pre & Post-BMP Period Hydrology 12/20/08-6/2/13

pre

Pasture-Control (gal)

Past

ure-

BMP

(gal

)

Pasture Paired Watershed:Total Suspended Solids

ComparisonTotal Suspended Solid Loads for only comparable storm events.

0 1,000,000 2,000,000 3,000,000 4,000,000 5,000,000 6,000,0000

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

4,000,000

4,500,000

5,000,000

f(x) = 0.288491324502112 x + 41602.9338896438R² = 0.515666086793298

f(x) = 0.785433104331726 x + 166651.722302231R² = 0.749528541885421

Pasture Pre-BMP & Post-BMP TSS Load 12/20/08-06/02/13

pre

Pasture-Control (kg)

Pas

ture

-BM

P (k

g)

Decrease in TSS for the treatment watershed from pre to post treatment periods

Pasture Paired Watershed:Total Phosphorus Comparison

0 5000 10000 15000 20000 25000 300000

5,000

10,000

15,000

20,000

25,000

f(x) = 0.666073261997441 x + 352.831164211523R² = 0.633064371914685

f(x) = 1.34445613904203 x + 456.131860821905R² = 0.853388714291037

Pasture Pre-BMP & Post-BMP TP Load 12/20/08-06/02/13

Pre

Pasture-Control (g)

Pas

ture

-BM

P (g

)

Pasture Paired Watershed:Total Kjeldahl Nitrogen Comparison

0 5000 10000 15000 20000 25000 30000 35000 40000 450000

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

f(x) = 0.984810799625441 x − 88.8272084315981R² = 0.821506976559331

f(x) = 1.20699415659013 x + 1046.87349918206R² = 0.763485651201399

Pasture Pre-BMP & Post-BMP TKN Load12/20/08-06/02/13

pre

Pasture-Control (g)

Pas

ture

-BM

P (g

)

Pasture Paired Watershed:Nitrate-Nitrogen Comparison

0 2000 4000 6000 8000 10000 120000

5000

10000

15000

20000

25000

30000

f(x) = 0.445337094437797 x + 356.452157882746R² = 0.231688811492995

f(x) = 0.894270351105529 x + 128.188493153112R² = 0.458096491228025

Pasture Pre-BMP & Post-BMP NOx-N Load12/20/08- 06/02/13

pre

Pasture-Control (g)

Pas

ture

-BM

P (g

)

Low R2 indicates an increase in Nitrate-Nitrite Nitrogen in the Treatment.

Low R2 indicates that the relationship is not significant plotted this way.

Mean Concentrations Pastures: Pre & Post Treatment

(12/07- 09/11) to (10/2011-06/2013)Constituent Treatment

(M) BeforeTreatment (M) After

Control (L) Before

Control (L) After

TKN (mg/L) 5.53 3.29 2.99 2.89NOx-N (mg/L) 0.79 0.74 1.05 0.53

NH4-N(mg/L) 2.33 0.54 0.68 0.47

TN (mg/L) 5 3 2 2TP (mg/L) 2.56 1.74 1.79 1.57

TSS (mg/L) 356 151 224 114E. Coli*

(mpn/100ml)1087 268 1755 601

*geomean

Load Changes from Pasture Outlets

(12/07- 09/11) to (10/2011-06/2013)Constituent Pasture Control

(L) Reduction (%)Pasture Treatment (M) Reduction (%)

TKN (kg/ha/yr) -25.4 4.7

NOx-N (kg/ha/yr) 39.8 -12.1

NH4-N (kg/ha/yr) 19.1 52.3

TN (kg/ha/yr) -5.6 2.1

TP (kg/ha/yr) -2.0 28.3

TSS (kg/ha/yr) 45.4 59.1

Conclusions:Difference in Treatment and

Control ReductionsConstituent Difference in Pasture Treatment

& Control Reductions (%)TKN (kg/ha/yr) 30.11

NOx-N (kg/ha/yr)* -51.87*

NH4-N (kg/ha/yr) 33.19

TN (kg/ha/yr) 2.1

TP (kg/ha/yr) 30.28

TSS (kg/ha/yr) 13.69

*Did not improve by comparison after BMP installation.

ConclusionsPasture Control (L)

Increasedo TKNo TNo TP

Decreasedo NOx-No NH4-No TSS

Pasture Treatment (M)

Increasedo NOx-N

Decreasedo TKNo NH4-No TNo TPo TSS

AcknowledgementsThank you!

Dr. Deanna Osmond Dr. Garry Grabow Dr. Matt Polizzotto Daniel Line Wesley Childres

Fundingo USDA NIFAo NC DENR, USEPA 319 pass-through funds