IOWA NUTRIENT REDUCTION STRATEGY

A science and technology-based framework to assess and reduce nutrients to Iowa waters and

the Gulf of Mexico

Spring 2013

1

Why? And Why Now?• Society expects higher environmental actions

from cities, industry and agriculture• Gulf Hypoxia Task Force requires plan to

reduce N and P load to Gulf by 45% by 2013• EPA requests strategy that emphasizes state

implementation of new and existing N and P practices for point and non-point sources

• Pending lawsuit to force EPA to adopt nutrient standards for 31 states of Mississippi River

2

Nutrient Reductions Needed to Meet Gulf of Mexico Hypoxia Goal

Nutrient Reductions• 45% reduction of nitrogen to Gulf• 45% reduction of phosphorus to Gulf

Statewide strategy by 2013 for achieving reductions

3

Nutrient delivery to the Gulf of MexicoState shares of the total nutrient flux

Nitrogen Phosphorus

Alexander et al, Environ. Sci. Techn., in press

4

Science Assessment

For nonpoint source landscapes, to achieve 45% N & P reductions identify– what practices needed– what level of practice adoption– what targeted locations for practices– what estimated costs– what resource assistance and programs are

needed

5

Nutrient Reduction Strategy – Science Team

• Matt Helmers – ISU – N Team Lead• Tom Isenhart – ISU – P Team Lead• John Lawrence – ISU• John Sawyer – ISU• Antonio Mallarino – ISU• William Crumpton – ISU• Rick Cruse – ISU• Mike Duffy – ISU• Reid Christianson – ISU• Phil Gassman – ISU• Dean Lemke – IDALS• Shawn Richmond – IDALS

• Jim Baker – IDALS/ISU• Keith Schilling – IDNR• Calvin Wolter – IDNR• Dan Jaynes – USDA-ARS• Mark Tomer – USDA-ARS• John Kovar – USDA-ARS• David James – USDA-ARS• Eric Hurley – USDA-NRCS• Mark David – Univ. of Illinois• Gyles Randall – Univ. of Mn• Katie Flahive - USEPA

6

Science Assessment• Establish baseline – existing conditions

– Major Land Resource Areas used to aggregate conditions• Extensive literature review to assess potential

performance of practices– Outside peer review of science team documents (practice

performance and baseline conditions)• Estimate potential load reductions of implementing

nutrient reduction practices (scenarios)– “Full implementation” and “Combined” scenarios

• Estimate cost of implementation and cost per pound of nitrogen and phosphorus reduction

7

Nitrogen or Phosphorus?

Nitrogen moves primarily as nitrate-N with water

Phosphorus moves primarily with eroded soil

8

Reaching the 45% goal• Point sources achieve maximum biological

removal rate: 4% N and 16% P• Nonpoint source goal becomes 41% N

and 29% P to achieve 45% goal for Iowa• Requires high adoption of full suite of

practices to reach the goal– Not simple– Not impossible

9

Nitrogen Reduction Practices 

Practice % Nitrate-N Reduction [Average (Std. Dev.)]

Nitrogen Management

Timing (Fall to spring) 6 (25)Source (Liquid swine

compared to commercial) 4 (11)

Nitrogen Application Rate Depends on starting pointNitrapyrin (N Serve) 9 (19)Cover Crops (Rye) 31 (29)

Land UsePerennial – Land retirement 85 (9)

Living Mulches 41 (16)Extended Rotations 42 (12)

Edge-of-Field

Drainage Water Mgmt. 33 (32)*Shallow Drainage 32 (15)*

Wetlands 52Bioreactors 43 (21)

Buffers 91 (20)**

10

Phosphorus Reduction Practices 

Practice % Phosphorus-P Reduction [Average (Std. Dev.)]

Phosphorus Management

Producer does not apply phosphorus until STP drops to

optimal level17 (40)

Source (Liquid swine compared to commercial) 46 (45)

Incorporation 36 (27)

No-till (70% residue) vs. conventional tillage (30%

residue)90 (17)

Cover Crops (Rye) 29 (37)

Land UsePerennial – Land retirement 75 (-)

Pasture 59 (42)Edge-of-Field Buffers 58 (32)

Phosphorus assessment does not include stream bed and bank contribution  11

Summary of Example Scenarios 

Initial Investment (million $)

Total EAC* Cost (million $/year)

Statewide Average EAC Costs ($/acre)Name

NCS1 3,218 756 36

NCS3 1,222 1,214 58

NCS8 4,041 77 4

12

Agricultural Nonpoint Sources

• Nutrient impairment is not mainly due to mismanagement of fertilizers and manures, but more to historic changes in land use and hydrology

13

Agricultural Nonpoint Sources

• Nutrient impairment is not mainly due to mismanagement of fertilizers and manures, but more to historic changes in land use and hydrology

• It is unlikely that in-stream phosphorus loading WQ goals will be achieved from only in-field P loading reductions to streams, given in-channel bed and bank erosion and resulting P loads

14

What’s New?

• Nonpoint and point sources integrated plan & working together towards goal

• Nonpoint source science assessment• Harness the collective initiative of Iowa ag

organizations, ag business & farmers• Major cities (102) and industries (46) treat

to remove nutrients• Coordination through water resources

coordinating council (WRCC)15

Goal – Iowa Leader

“As Iowa is a national and global leader in the production of food and renewable fuels, a goal of this strategy is to make Iowa an equal national and global leader in addressing the environmental and conservation needs associated with food and renewable fuels production.”

16

Iowa Strategy Approach – Nonpoint Sources

• Achieve nutrient load reductions through voluntary technology-based actions, while

• Continuing to assess and evaluate nutrient water quality standards

17

22 Nonpoint Source Actions In 8 Categories

1. Watershed prioritization & goals

2. Setting priorities

3. Research & technology

4. Strengthen outreach, education, collaboration

5. Increased public awareness & recognition

6. Funding

7. Accountability & verification measures

8. Public reporting

18

Strategy Implementation

• 12 of 22 nonpoint source action items are underway now through WRCC & agencies

• ISU Extension Outreach 2012-13– Integrated Crop Management Conference –

1000 CCA’s– Pesticide & manure applicator training, Crop

Advantage Series meetings – 26,000 farmers

• Ag landowners, farmers encouraged to evaluate practices, continue adoption

19

Why is Strategy Important?

• Based on sound science in Iowa, for Iowa• Meaningful and measureable progress• Builds on current programs and targeted

watersheds • Utilizes the policy framework which will

provide greatest progress and success• Improves water quality in Iowa and Gulf of

Mexico

20

www.nutrientstrategy.iastate.edu

Iowa Department of Agriculture and Land Stewardship

www.IowaAgriculture.gov

21