AN INNOVATIVE APPROACH TO REDUCING NUTRIENT LOSSES FROM

AGRICULTURAL LANDSCAPES

THE WATERSHED APPROACH

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

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

We need to treat the causes, not the symptoms, of nutrient loss

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, JAWRA, 2015a

McLellan et al, JAWRA, 2015a

Decreased nitrogen transport

Decreased nitrogen transport

Decreased nitrogen sources

Increased nitrogen

sinks

WAYS TO DECREASE NUTRIENT LOSSES

EMPHASIS ON CRITICAL SOURCE

AREAS

NEED EMPHASIS ON CRITICAL SINK AREAS

Restoring sinks on 1-2% of the landscape can decrease downstream nutrient loads by 45% (McLellan et al, JAWRA, 2015)

If we reduce nutrient sources and transport by implementing improved fertilizer management and cover crops on all cropland in the Basin, we can reduce downstream nutrient loads by 30%.

Getting to 45%Reducing hypoxia in the Gulf of Mexico requires a 45% reduction in nitrogen loads from the Upper Mississippi-Ohio River Basin.

Is it realistic to think that all producers in the Basin will implement improved fertilizer management and cover crops on all their land?

How do we fill the gap?

McLellan et al, JAWRA, 2015b

Solving Regional Water Quality Problems Through Local Watershed Projects

McLellan et al, JAWRA, 2015b

• USGS SPARROW model

• Map land eligibility for practices at small watershed scale

• Model trade-offs between in-field and landscape-scale practices

• Target conservation efforts to where they will create the greatest load reductions

• Minimize cropland conversion

Why local (HUC-12) projects?

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 (e.g. ponds, wetlands)

Restore/create N sinks:• Riparian buffers• Pothole-type wetlands• Created wetlands• Two-stage ditches• Stream restoration• Floodplain reconnection

A Systems Approach at Small Watershed Scale

THE WATERSHED APPROACH:

Follow the nutrient flowpaths: reduce sources, reduce transport, restore sinks

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: a simple approach to identifying dominant flowpaths

Schilling et al, Envtl. Mgmt., 2015

Distribution of Different Types of Watersheds Across the UMORB

Poorly Drained Soils Well Drained Soils

High 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

An integrated suite of practices across the landscape from field to

farm to ditch/stream/lake…

…that recognizes that a watershed is also a community where people live, work and play

The Watershed Approach

Solving nutrient pollution problems

Solving social and economic problems: food

production, economic viability,

flood/drought protection, recreational

opportunities etc.

A biophysical system at

watershed scale

A social system at watershed

scale

SOLVING MULTIPLE PROBLEMS IN A WAY THAT WORKS FOR THE COMMUNITY

Characteristics of the watershed approach

A systemic, strategic and comprehensive approach to conservation that:• Is goal-oriented• Broadens the focus of conservation from field- and farm-

scale to watershed-scale• Identifies priority conservation practices and practice

locations based on understanding of the flow of nutrients across the landscape

• Engages stakeholders in watershed planning• Engages public and private partners in education,

outreach, technical support and funding

Stages in the Process

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.

Key Questions in Each Watershed

• Are stakeholders aware of water quality problems and invested in solving them?• Social capacity analysis

• What is a reasonable water quality goal?• Stakeholder-expert discussion

• What are the dominant sources and transport pathways of nutrients?• Hydrologic watershed classification (Schilling et al, 2015)

• How can we best reduce nutrient losses along these flowpaths?• Priority practices for each watershed class (Schilling et al, 2015)

• What are stakeholders’ attitudes and beliefs about these practices?• Structured interviews

• Where is it theoretically possible to put priority practices in the watershed?• LiDAR-based conservation planning tool (Tomer et al, 2014)

• What combination of priority practices and locations is needed to meet the water quality goal?• Alternative conservation scenarios (Tomer et al, 2015)

Stages in the Process

Watershed Planning and Plan Implementation in Beargrass Creek, IN

Supported by an NRCS Conservation Innovation Grant

The Story Continues…