AN INNOVATIVE APPROACH TO REDUCING NUTRIENT LOSSES FROM

AGRICULTURAL LANDSCAPES

THE WATERSHED APPROACH

The need for a new approach to agricultural conservation

What is the watershed approach?

How do we implement the watershed approach on the ground?

Case study: Matson Ditch, St. Joseph River, IN

Lessons learned and transferability

SYMPOSIUM OUTLINE

Why Do We Need a New Approach to Conservation?

• Growing awareness of problems associated with nitrogen losses from agricultural landscapes.

• Reducing nitrogen losses requires a different approach to agricultural conservation.

• Nitrogen moves primarily with subsurface flows• Nitrogen-related water quality problems are invisible on

the farm but affect downstream communities at a regional scale

• Past conservation efforts have been very successful in reducing soil erosion (and phosphorus losses).

• But much more needs to be done to reduce phosphorus losses from agricultural landscapes.

The Scale of the Solution Needs to Match the Scale of the Problem

45% reduction in downstream loads

Signficant reductions in stream N and P needed to meet new nutrient criteria

We need to treat the causes, not the symptoms

How have these landscapes changed in the past 150 years?

What causes nutrient losses from Midwestern landscapes?

LANDSCAPE CHANGES

INCREASED NUTRIENT EXPORT

McLellan et al, in press

Ways to increase nutrient losses

Decreased nitrogen transport

Decreased nitrogen transport

Decreased nitrogen sources

Increased nitrogen

sinks

Ways to decrease nutrient losses

Decrease N sources:• Improve nutrient management• Use extended rotations and/or conservation cover• Use cover crops

Decrease N transport:• Use cover crops• Use conservation tillage (soil water storage)• Use controlled drainage• Use water storage structures in the landscape (ponds, wetlands

etc.)

Restore N sinks:• Wet places + organic material + time = denitrification (N2 gas)• Restore wetlands• Create wetlands (add organics to wet places, or make organic-rich

places wet)

How do We Decrease N (or P) Loss From the Landscape?

A SYSTEMS APPROACH AT WATERSHED SCALE

Restoring sinks on 1-2% of the landscape can decrease downstream nutrient loads by 45% (McLellan et al, in press)

THE WATERSHED APPROACH: A SYSTEMIC AND STRATEGIC

APPROACH AT WATERSHED SCALE

Following the flow of water…surface and subsurface…

Reduce sources, reduce transport, restore sinks

Across the landscape from field to farm to ditch/stream/lake

Use practices to reduce and recycle nutrient inputs within fields

Use practices within and at the edge of fields to capture flows and prevent nutrient losses

Use practices in riparian areas, ditches and streams to intercept and treat nutrients lost from fields

Identify potential practices all along the flowpaths from fields to ditches, streams and rivers;

Target field-scale practices (reduce, recycle) to areas most vulnerable to nutrient loss;

Target beyond-field practices (trap and treat) to locations where they intercept the largest flows.

IMPLEMENTING THE WATERSHED APPROACH

SCIENCE: Identify priorityconservation practices and locations

SOCIAL/ECONOMIC INCENTIVES:Encourage producers to adopt priority practices at priority locations

Systemic, strategic, solutions-oriented, community-focused

Decrease N sources:• Improve nutrient management• Use extended rotations and/or conservation cover• Use cover crops

Decrease N transport:• Use cover crops• Use erosion control practices • Use conservation tillage (soil water storage)• Use water storage structures in the landscape (ponds, wetlands

etc.)

Restore N sinks:• Wet places + organic material + time = denitrification (N2 gas)• Restore wetlands• Create wetlands (add organics to wet places, or make organic-rich

places wet)

The Scientific Heart of the Watershed Approach

What are the sources of N?

How does N move across the landscape?

Where can we restore sinks?

Steps in Watershed Analysis

• Look at watershed geology, soils, topography, nutrient budgets Dominant sources and flowpaths

• How can we best avoid, control and treat nitrogen and phosphorus along these flowpaths? Priority conservation practices

• Where is it (theoretically) possible to put these practices in the landscape? Priority locations where the practices will do the

most good

• How many of what kinds of practices are needed to achieve water quality goals? Conservation scenarios

Poorly Drained Soils Well Drained SoilsHigh relief (slopes > 5%) Farming on sloping lands in old

glacial landscapes, thin loess or paleosols, high runoff potential

Farming on sloping lands underlain by shallow bedrock or sands, potential karst, baseflow-dominated with high runoff potential during storm events

Low relief (slopes < 5%) Dissected (slopes 2<x<5% )

Non-dissected (slopes < 2%)

Farming on sand plains, floodplains, terraces, infiltration-dominated system, high baseflow

Farming on upland divides and stepped terraces, high runoff potential with tiling along waterways

Farming on hydric soils, widespread artificial drainage

Agro-hydrologic analysis: geology, soils and topography determine dominant flowpaths

Schilling et al, in review

Distribution of Different Types of Watersheds Across the UMORB

Poorly Drained Soils Well Drained SoilsHigh relief (slopes > 5%) Grass waterways, contour filter

strips, terraces, ponds, riparian buffers, cover crops

In-field source controls important, riparian buffers, springs, seeps, floodplain reconnection, in-stream practices

Low relief (slopes < 5%) Dissected (slopes 2<x<5% )

Non-dissected (slopes < 2%)

In-field source controls important, 2-stage ditches, floodplain reconnection, off-channel wetlands

Grass waterways, filter strips, ponds, cover crops, riparian buffers, wetlands, bioreactors

Drainage water management, treatment wetlands, bioreactors, 2-stage ditches

Different Priority Practices for Different Types of Watersheds

Practices to Reduce Nutrient Losses in Surface Runoff

No-till Grass waterways Filter strips

Riparian buffers Ponds/basins Conservation cover

Controlled drainage

Bioreactor

Treatment wetland Saturated buffers

Practices to Reduce Nutrient Loss in Tile Drainage

Saturated buffers Stream diversion

Cover cropsNutrient management

Practices to address nutrient loss in subsurface flow

WHAT WOULD THIS LOOK LIKE IN REAL WATERSHEDS ACROSS THE MIDWEST?

Project goal: develop a set of watershed planning resources to assist communities in meeting regional

water quality goals.

EDF-NRCS Watershed Planning Demonstration Project

Watershed planning resources: new conservation practices, new conservation planning tools, and

new conservation planning processes.

EDF PowerPoint TemplateTitle Slide

Project CollaboratorsToby Dogwiler, Winona State UniversityAdam Kiel and Keegan Kult, Iowa Soybean AssociationJoe Magner, University of MinnesotaLinda Prokopy and Nick Babin, Purdue UniversityKeith Schilling and Calvin Wolter, IA-DNRDoug Smith, USDA-ARS-NSERLMark Tomer and Sarah Porter, USDA-ARS-NLAE

The staffs of Dekalb SWCD (IN) and Winona SWCD (MN) and of NRCS Field Offices in Dekalb County, IN, Floyd/Chickasaw Counties (IA) and Olmsted/Winona Counties (MN).

Numerous producers in Beaver Creek (IA), Matson Ditch (IN) and Middle Fork Whitewater (MN)

Funding SupportEDF gratefully acknowledges support provided through a Contribution Agreement from NRCS, and grants from the Joyce Foundation and the Walton Family Foundation.

Poorly Drained Soils Well Drained SoilsHigh relief (slopes > 5%) Farming on sloping lands in old

glacial landscapes, thin loess or paleosols, high runoff potential

Farming on sloping lands underlain by shallow bedrock or sands, potential karst, baseflow-dominated with high runoff potential during storm events

Low relief (slopes < 5%) Dissected (slopes 2<x<5% )

Non-dissected (slopes < 2%)

Farming on sand plains, floodplains, terraces, infiltration-dominated system, high baseflow

Farming on upland divides and stepped terraces, high runoff potential with tiling along waterways

Farming on hydric soils, widespread artificial drainage

3 Demonstration Watersheds Representing 3 Different Types

Whitewater, MN

Beaver Creek, IA

Matson Ditch,

IN

MATSON DITCHWATERSHED PLANNING DEMONSTRATION

PROJECT

Matson Ditch Watershed Planning Project

• Nutrient sources and flowpaths

• Priority conservation practices to address these

• Practice placement in the watershed

• Conservation scenarios to achieve 40% P reduction goal

• Insights from social science

• Engaging partners

• Lessons learned

QUESTIONS?

POTENTIAL CONSERVATION PRACTICES FOR MATSON DITCH

Innovative practices are highlighted; practices that are useful for treating high flows are shown with an asterisk*.

Improved nutrient managementConservation tillageCover cropsBlind inletsWetland restorationGrass waterwaysPonds*Nutrient removal wetlands Stream diversions (off-channel storage) including gravel pits*Tile diversions/riparian bioreactors Two-stage ditches*

PRACTICE COMPARISON TABLEPractice Acres to achieve a 

40% reductionReduction goal achieved?

Practice lifetime 

Nutrientmanagement

10,000 + NO Annual

No‐till 10,000 + NO Annual

Cover crops 10,000 + NO Annual

Extended rotations Annual

Blind inlets Every inlet +  NEARLY

Grass waterways 730 acres ?

Ponds 200 acres ? Annual dredging

Nutrient removal wetlands

450 acres ? 50 years

Stream diversions 20 acres ? Need to harvestvegetation

Tile diversions with slag

50 acres ? Need to clean out gravel

Two stage ditches 5 acres ? Need to harvest vegetation