using agri environment part i

Using agri‐environmental indicators to track changes in the risk of nutrient and sediment losses in the Lake Erie basin:

I. Grand River Case StudyNatalie Feisthauer, Pamela Joosse and Keith Reid

Science and Technology Branch Agriculture and Agri‐Food Canada

69th SWCS Conference, Lombard, IL July 27‐30th 2014

National Agri‐Environmental Health Analysis and Reporting Program (NAHARP)

• Established in 2003 to develop a set of science‐based environmental indicators specific to the agriculture and agri‐food sector

• 23 indicators including:– Risk of soil erosion on cropland– Wildlife habitat capacity on farmland– Agricultural greenhouse gas budget indicator

• Provides results informing on topics such as:– Changes in agriculture environmental performance

over time– The impacts of adopting best management practices

• Current report #3 (2010) incorporates Census of Agriculture (and other) data from 1981‐2006

• Report #4 under development


IROWC‐P: Indicator of Risk of Water Contamination by Phosphorus (van Bochove et al., 2009, 2010)• Temporal & spatial trends for risk of surface water contamination by P from Canadian ag land• Estimates phosphorus in the soil after crop harvest (P‐balance)• Estimates partitioning of water (field scale) between surface runoff and soil leaching (VSMB)• Hydrological connectivity factors used to estimate transport of P from field to surface water

RSN: Residual Soil Nitrogen (Drury et al., 2010)• Estimates the inorganic nitrogen in the soil after crop harvest (N‐balance)

SoilERI: Soil Erosion Risk Indicator (Lobb et al., 2010; Li et al., 2008)• Determines the risk of soil erosion by water (WatERI), tillage (TillERI), and wind (WindERI)WatERI (McConkey et al., 2010, Li et al., 2008)

• Determines soil loss accounting for rainfall erosivity, crop and tillage type, and inherent erodibiltyof soil (Revised Universal Soil Loss Equation 2 equivalent)

• Includes inherent erodibility of each soil (k) and slope steepness (s) and slope length (L) factors

van Bochove et al., in: Eiler et al., 2010. Environmental Sustainability of Canadian Agriculture, Report #3.


• Geospatial framework is Soil Landscapes of Canada (SLC) (1:1 million scale)• Model assumptions made in order to apply to all regional conditions

– Challenge is to use these indicators at smaller geographic scales

• Largest Canadian tributary to Lake Erie – 25% of Canadian land that drains into Lake Erie

• 10% of total Canada/US drainage area• Recently (2013) renewed Water Management Plan

to guide development, programs and projects over the next 30 years

• AAFC identified agricultural landscapes within the Grand River watershed with the greatest relative risk of loss of nutrients and sediment

• Proof‐of‐concept pilot for the application of components of national‐scale NAHARP indicators in a risk assessment at a watershed‐scale

• Precursor to the full‐scale application of this approach to the entire Canadian Lake Erie basin

www.google.ca/maps

www.grandriver.ca

• 6,800 km2 (2,800 mi2) • 985,000 people (80% urban)• Projected to 1.53 million by 2051• 71% (4,800 km2) of total area in

agricultural production• ~ 6,400 active farms• Diverse agriculture (livestock,

cash crop, horticulture, specialty)• Diverse topography

Grand River Watershed

Our approach

• Source: nutrient balance =

• Transport Pathway: conduit by which nutrients/soil are transported from the field [to surface or groundwater]; depends on nutrient form, soil type, and landscape features

• Risk of loss from agricultural landscape– Considered potential for movement from edge of field/bottom of

rooting zone only– In our analysis no direct consideration of hydrological connectivity to

surface or groundwater

Risk = Source x Transport Pathway

nutrient input (fertilizer, manure addition)− nutrient removal (removal with crop harvest) nutrient balance (nutrients remaining that year)

Riskof Loss = Source X Dominant

Transport Pathway =Source

XTransport Pathway

NAHARP Model Surrogate

NAHARP Model Component

PP = Soil P X Water erosiontowards surface water = Cumulative P*

(kg P/ha) IROWC‐P X Inherent erodibility of soil (k*L*S) WatERI

DRP = Soil P X Runoff towards surface water = Cumulative P*

( kg P/ha) IROWC‐P X Surface runoff (R, mm)§IROWC‐P VSMB

Soil = Soil X Water erosion towards surface water = k (erodibility of soil)

WatERI X L*S (length, slope of landscape)WatERI

NO3‐ = Soil N X Leaching

through soil = Average§ N‐balance (kg N/ha) RSN X Deep drainage (D, mm)§

IROWC‐P VSMB

Soil = Soil X Water erosion towards surface water = Average§ WatERI (t soil/ha/year)

Our approach• Risk determined for each SLC in the watershed

* Because P is conserved from year to year a cumulative P parameter for 2006 was developed by linear interpolation of the P‐balance values of each of the six Census years (1981‐2006)

§ Average value of each of the six Census year data (1981‐2006)

• Soil Landscapes of Canada (SLC) also used to geospatially describe the watershed

• SLCs based on existing provincial soil survey maps

• SLCs follow landforms and ecological land classification, not hydrological or political boundaries

Characterizing the Grand River Watershed

Risk = Source x Transport Pathway

• NAHARP model components for Source and Transport Pathway arederived from SLC‐interpolated based data

• Provides geospatially referenced source and transport data for watershed

Source: Phosphorus (PP & DRP)

• The capacity of P to bind to soil meansthere is potential for it to accumulate over time with successive positive P‐balances

• Cumulative P (kg P/ha) for eachSLC in the Grand River watershed wascalculated via linear interpolationfrom P‐balance data from 1981 to 2006

• 60 kg P/ha categories approximate a 2 mg/kg (ppm) increase in soil test P

• SLCs with higher cumulative P havegenerally more livestock but alsosignificant horticulture production

asdfs

< 0

Cumulative P (kg P/ha)

Source: Phosphorus (PP & DRP)

• P‐balance (kg P/ha/year) from each Census year data was also used to calculate trends over a 25‐year period (1981‐2006)

• No increasing linear trends in any SLCs in the watershed

• Significantly declining P‐balance trends in some SLCs in the watershed

Transport Pathway for PP: Erosion• Potential for soil erosion estimated

from inherent soil characteristics ofsoil erodibility (k), slope steepness (S)and slope length (L) of soils in a given SLC

• Does not take into considerationland use or management practices

• Represents the “inherent” relative riskof soil erosion among the SLCs in thewatershed; other models (e.g., WatERI)take into consideration rainfall erosivity, crop type and tillage practices

Relative Risk: Phosphorus (PP)• Relative risk of loss of PP

among SLCs in Grand River watershed

• Equal weighting of source and transport pathway

• Risk of loss greatest in headwaters of Whiteman’s Creek, upper Conestogo, upper and mid‐reach Nith

• Generally align with GRCA analyses using in‐stream data and knowledge of landscape/land use

X =

Transport Pathway for DRP: Water Runoff

• Average runoff (mm water/year) for each SLC in the Grand River watershed for the six Census years (1981‐2006)

• Runoff parameter incorporates soil characteristics (e.g., texture, drainage class), precipitation and crop evapotranspiration

• Runoff is excess water that can travel via surface or tile drain pathways

• Higher levels of runoff in the north tillplains, and the south clay plains near the mouth of the river

• Less runoff in morainal mid‐reachof the river

Relative Risk: Phosphorus (DRP)• Relative risk of loss of

DRP among SLCs in Grand River watershed

• Equal weighting of source and transport pathway

• Risk of loss greatest in upper Nith and Conestogo riversand headwaters of Whiteman’s Creek

• Generally align with GRCA analyses using in‐stream data and knowledge of landscape/land use

Relative Risk of Lossof Dissolved ReactivePhosphorus via Runoff

X =

Relative Risk of Lossof Dissolved Reactive Phosphorus via Runoff

Nutrient Form (and thereby Transport Pathway) Makes a Difference: DRP vs PP

Relative Risk of Lossof Dissolved ReactivePhosphorus via Runoff

Summary

• The relative risk of loss of phosphorus (particulate and dissolved), soil and nitrogen (not shown) was determined among geospatially explicit landscapes within the Grand River watershed

• Results of this project are complementary to work conducted by the GRCA to infer nutrient and sediment contributing regions from in‐stream Grand River data, and knowledge of the watershed physiography and land use by the Grand River Conservation Authority (GRCA, 2013)

• Results from this pilot proof‐of‐concept study in the Grand River watershed showed that this approach is feasible and has the potential to be transferred to other regional watersheds, such as the Lake Erie basin

Acknowledgements:• Agriculture and Agri‐Food Canada (AAFC): Donna Speranzini, Jillian Smith,

Elizabeth Woyzbun, Jean‐Thomas Denault, Sheng Li, Craig Drury, Zisheng Xing and co‐op students Sarah Luce, Jack Hinds, Alex Watkins and Jean Gordon

• Grand River Conservation Authority (GRCA): Sandra Cooke

• Members of the multi‐agency Grand River Water Management Plan Water Quality Working Group

Citations:

Eilers, W., R. MacKay, L. Graham and A. Lefebvre (eds). 2010. Environmental Sustainability of Canadian Agriculture: Agri‐Environmental Indicator Report Series —Report #3. Agriculture and Agri‐Food Canada, Ottawa, Ontario.• Drury, C.F., J. Yang, R. De Jong, T. Huffman, X. Yang, K. Reid and C.A. Campbell. 2010. Residual Soil Nitrogen. Pages 74 – 80 in Eilers, W., R.

MacKay, L. Graham and A. Lefebvre (eds). 2010.• Lobb, D.A., S. Li and B.G. McConkey. 2010. Soil Erosion Risk (integration the risks of wind, water and tillage erosion). Pages 46 – 53 in

Eilers, W., R. MacKay, L. Graham and A. Lefebvre (eds). 2010.• McConkey, S. Li, M.W. Black and D.A. Lobb. 2010. Water Erosion Risk Indicator. Page 48 in Eilers, W., R. MacKay, L. Graham and A.

Lefebvre (eds). 2010.• van Bochove, E., G. Thériault, J.‐T. Denault, F. Dechmi, A.N Rousseau and S.E. Allaire. 2010. Risk of Water Contamination by Phosphorus.

Pages 87 – 93 in Eilers, W., R. MacKay, L. Graham and A. Lefebvre (eds). 2010.

Li., S., B.G. McConkey, M.W. Black and D.A. Lobb. 2008. Water Erosion Risk Indicator (WatERI) Methodology in Soil erosion risk indicators, Technical Supplement. Ottawa, ON, Canada:Agriculture and Agri‐Food Canada

van Bochove, E. and J.‐T. Denault (editors). 2009. Indicator of Risk of Water Contamination by Phosphorus (IROWC‐P). A Handbook for presenting the IROWC‐P Algorithms. Research Branch. Agriculture and Agri‐Food Canada. Quebec. Contribution No. AAFC/AAC, 94 pp.

Grand River Water Management Plan. 2013. Sources of Nutrients and Sediments in the Grand River Watershed. Prepared by the Water Quality Working Group. Grand River Conservation Authority, Cambridge, ON.

• Excluded SLCs that would unduly influence the characterization of the watershed based on activities or landscapes occurring predominantly outside its boundaries

• Excluded SLCs that:• Comprised less than 2.5% of watershed rural land; and,• Have greater than 80% of its rural land located outside the watershed

Characterizing the Grand River Watershed

GuelphKitchener‐Waterloo

Cambridge

Brantford

Lake Ontario

Lake Erie