integration of prairie strips into agricultural landscapes to enhance ecosystem services: water...
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Integration of Prairie Strips into Agricultural Landscapes to Enhance Ecosystem Services: Water Quality Benefits
prairiestrips.org
• Leopold Center for Sustainable Agriculture
• Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation
• U.S. Forest Service Northern Research Station
• Iowa State University College of Agriculture and Life Sciences
• USDA-NCR-SARE
• USDA-NIFA-AFRI-Managed Ecosystems
• University of Iowa
Funding
Evaluation of Ecosystems Services in Mixed Annual-Perennial Agroecosystems
• Hypothesis: Strategic placement of small amounts of perennial cover within agriculturally-dominated landscapes will have disproportionate benefits on biophysical and socioeconomic systems
• To address this hypothesis we have four components:– Ecohydrology– Biodiversity– Socioeconomic– Educational and Extension
reconstructed prairie
corn - soybean row crops, ZERO TILLAGE
Experimental Watershed Treatments
12 watersheds: Balanced Incomplete Block Design:
3 reps X 4 treatments X 3 blocks
0% 10% 10% 20%
STRIPS: Science-based Trials of Row-crops Integrated with PrairiesNeal Smith National Wildlife Refuge, Prairie City, IA
12 experimental watersheds, 0.5 to 3.2 ha each, 6 to 10% slope
Four treatments:100% crop (no-till)10% buffer, at toe slope10% buffer, in contour strips20% buffer, in contour strips
Site History• Watersheds under primarily bromegrass cover until fall
2006• Watershed instrumentation: spring 2005• Pre-treatment data collection: 2005 – 2006 field
seasons• Treatment establishment: fall 2006 & spring 2007
– Soybean planted in 2007– Prairie strips sown in July 2007
• No-till corn-soybean rotation in cropped areas
Watershed Characteristics Size
(acre)Slope
(%)Location and percent of grass filters*
Basswood-1 1.3 7.5 10% at footslopeBasswood-2 1.2 6.6 5% at footslope and 5% at upslopeBasswood-3 1.2 6.4 10% at footslope and 10% upslopeBasswood-4 1.4 8.2 10% at footslope and 10% upslopeBasswood-5 3.1 8.9 5% at footslope and 5% upslopeBasswood-6 2.1 10.5 All rowcropsInterim-1 7.4 7.7 3.3% at footslope, 3.3% at sideslope, and
3.3% at upslope
Interim-2 7.9 6.1 10% at footslope Interim-3 1.8 9.3 All rowcropsOrbweaver-1 2.9 10.3 10% at footslopeOrbweaver-2 5.9 6.7 6.7% at footslope, 6.7% at sideslope, and
6.7% at upslope
Orbweaver-3 3.1 6.6 All rowcrops
*Percent of grass filters = area of filters / area of watershed
Surface Runoff MonitoringH-flumes monitor movement of water, sediment, and nutrients
Precipitation
Surface Runoff
Helmers et al., 2012
Sediment Loss in Runoff (2007-2011)
Helmers et al., 2012
>95% Reduction in sediment export from watersheds with prairie filter strips
Phosphorus Loss in Runoff (2007-2011)
Helmers et al., in press
>90% Reduction in TP export from watersheds with prairie filter strips
Total Nitrogen Loss in Runoff (2007-2011)
Helmers et al., in press
>90% Reduction in TN export from watersheds with prairie filter strips
Nitrate-N Loss in Runoff (2007-2011)
Helmers et al., in press
Nitrate-N Concentrations in Groundwater
NO3-N concentrations in shallow groundwater at (a) upslope and (b) toeslope positions. Error bars denote the standard deviation of the replicates. Statistical difference of mean nitrate concentration between treatments (grass filters vs. cropland) was indicated for each monitoring period using two significant levels (** p < 0.05, * p < 0.1).
Visual Examples (4 inch rain in June 2008)
100% Crop 100% Prairie10% Prairie90% Crop
Soil Carbon and Nitrogen
Integrating prairie into crop fields can blur the lines between production and conservation lands…
Photo: A. MacDonald
Matt HelmersAssociate Professor Ag and Biosystems Eng.Iowa State University (515)[email protected]
prairiestrips.org
Vegetation in strips, 2008-2011
2008 2009 2010 2011
Number of species–all 38 45 51 55
Number of species–native perennials 18 24 29 33
Percent cover–all species 82 75 105 115
Percent cover– native perennials 18 22 56 67
Plant diversity in the strips is increasing, especially for native perennial species.Time effects: p<0.0001 for each response.Hirsh et al., 2013
Cover by dominant species in strips, 2011
• Kentucky and Canada bluegrass, Poa pratensis/compresa, 25.1%• Canada goldenrod, Solidago canadensis, 11.6%• Gray-headed coneflower, Ratibida pinnata, 6.5%• Queen Anne’s lace, Daucus carota, 6.4%• Indiangrass, Sorghastrum nutans, 5.6%• Wild bergamot, Monarda fistulosa, 4.5%• Big bluestem, Andropogon gerardii, 4.3%• Smooth brome, Bromus inermis, 4.0%• Hairy aster, Aster pilosus, 3.7%• Reed canary grass, Phalaris arundinacea, 3.1%• Ox-eye, Heliopsis helianthoides, 3.1%
Hirsh et al., 2013(native perennials)
52 speciesoverall
11 species nesting
A. MacDonald
Total Bird Abundance (TBA)Range = 0-33 individuals
Mean = 5
A. MacDonald, unpublished data
Species RichnessRange = 0-14 Species
Mean = 2.6
A. MacDonald, unpublished data
10% bottom
10% strips 20% strips 100% crop0
2
4
6
8
10
Treatment
Perc
ent p
lant
cov
er
Mean percent cover by non-crop species (‘weeds’) in cropped areas, 2009-2011
No significant differences in weed coveramong all-crop and diversified watersheds
Hirsh et al., 2013
A B C D0
20
40
60
80
100
120
140
160
180
200
2008
2010
2012
Yie
ld (
bu/a
c)
A B C D52
54
56
58
60
62
64
66
68
2007
2009
2011
Yie
ld (
bu/a
c)
Soybeanstrips vs. all crop: p=0.95
CornStrips vs. all crop: p=0.46
10%bottom
10%contour
20%contour
Allcrop
10%bottom
10%contour
20%contour
Allcrop
Corn and soybean yields from cropped areas of the catchments were unaffected by the presence or absence of prairie strips.
M. Maier, unpublished data
Site prep & planting costs…≤ 10%
of total cost
Opportunity Cost of land = foregone rent or revenue
+Upwardsof ~ 90% total cost
Management costs…
+~ 10% - 15% of
total cost
1. 4% discount rate; 15-year management horizon; average Iowa land rent charge. 2. Assumes 1 ac of prairie treats about 9 ac of row crops3. Represents treated acre costs to farmer after CRP
Annualized Total Costs 1
Higher Quality Land
(CSR 83)
Medium Quality Land
(CSR 73)
Lower Quality Land
(CSR 60)
Cost per treated 2
acre~ $40 ~ $30 ~ $24
Cost per treated acre with CRP 3
$5 $4 $3
Cost calculation assumption: One acre of prairie “treats” the run-off
from about 9 acres of row crops
Average Cost of Strips to Farmers
Keep in mind that cost scale with opportunity costs
prairiestrips.org
Matthew J. Helmers1, Lisa Schulte-Moore2, J. Arbuckle3, Pauline Drobney4, Mary Harris2, Randall K. Kolka5, Matt Liebman6, Matt
O'Neal7 and John Tyndall2
(1) Ag & Biosystems Engineering, Iowa State University, Ames, IA(2) Natural Resource Ecology & Management, Iowa State University, Ames, IA(3) Sociology, Iowa State University, Ames, IA(4) U.S. Fish and Wildlife Service, Prairie City, IA(5) USDA Forest Service (FS), Grand Rapids, MN (6) Agronomy, Iowa State University, Ames, IA(7) Entomology, Iowa State University, Ames, IA
Conclusions
• Strategic placement of prairie: – Reduced sediment and nutrient loss– Increased vegetation diversity– Increased bird abundance– Did not impact weed pressure– Did not impact yield (on a per unit area
basis)– Is a cost effective strategy compared to
other conservation practices