Implementation and Monitoring to. Reduce Agricultural Impacts on ... Develop soil P thresholds. Incorporate into site assessment tools for P-based management ...
Implementation and Monitoring to Reduce Agricultural Impacts on Water Quality: US Experience Curtis Dell, Peter Kleinman, and Tamie Veith U.S. Department of Agriculture-Agricultural Research Service Pasture Systems and Watershed Management Research Unit University Park, PA, USA Rory Maguire Crop, Soil, and Environmental Science Department Virginia Tech Blacksburg, VA, USA
Recent water quality issues in the US P primary national focus in last 15 yr Concern over increasing eutrophication of water bodies such as the Chesapeake Bay
Recent water quality issues in the US Contributing factors
Concentration of animal production Fewer, but larger animal feeding operations
N to P imbalance in manure Applying manure to meet crop N requirement
can result in excess soil P
Farming System and P Balance Crop
Dairy
Pig
Poultry
- - - - - - kg P/ha/yr - - - - - -
Input Fertilizer
18
11
--
--
Feed
--
30
104
1690
Output
16
12
20
515
Balance
2
29
84
1175
Pennsylvania farms Cash crop 65 Holsteins 1280 hogs 75,000 birds 30 ha
40 ha
30 ha
12 ha
Recent water quality issues in the US Ongoing N issues, but less national focus than P Grassland/grazing land impacts on water quality receiving limited attention Perceived as a low impact land use Manure application to grasslands addressed in regions where P in runoff is an issue
US water quality regulations Clean Water Act (1972) Confined Animal Feeding Operation Rule (2002) Permits required if: 1. ≥ 200 animal units 2. Animals confined ≥ 45 days in 12 mo 3. Waste discharge to a water body Permit requirements: 1. No discharge for less than 25-yr storm
2. Comprehensive nutrient management plan
Voluntary compliance for non-CAFO’s, but cost-
share incentives
Cooperative Projects
National Phosphorus Project Locations
USDA AL AR CO FL GA IA ID
IN IL OH OK OR MD MS
NE PA SC TX WA WI WV
University AL AR DE FL GA IN
KS VA MD VT NC WA NY WI OR WV TN PR
The National P Project Objectives Develop soil P thresholds
Getting from here
Incorporate into site assessment tools for P-based management 2 1.5
The simulator is mobile
Runoff P (mg/L)
1 0.5 0
To here
0
To here !
200
400
Soil test P (mg/kg)
600
Standardized protocols Nozzle to simulate rainfall
Runoff boxes
Critical Source Areas (CSAs) High P source areas Runoff source areas CSAs
X Outlet
The P Index - a tool for improved farm nutrient management Transport
Source
Climate
Soil P content
Surface runoff class
Fertilizer P application
Erosion potential Proximity to stream channel Leaching potential
Rate, method, timing
Manure P application Rate, method, timing
The P Index P Index Rating Low (clear) Medium High
~90% of P export comes from 200 farmers surveyed Local vs. New York City benefit and responsibility large factors Additional obligations for landowners, such as Build and maintain fences Install watering equipment Differences in attitudes between long-time farmers and newer “hobby” farmers
Optimization of BMP Selection and Placement Expected outputs
Components/sources Baseline (preBMP) P losses SWAT model
Average annual baseline P loads Extent of P-loss (high / low)
-Multiple scenarios -Associated scenario costs -Associated scenario loads
BMP effectiveness estimates - BMP database/tool
Site specific BMP effectiveness estimates
BMP costs – Delaware county records
Annualized BMP costs
-Cost-effectiveness based on load reductions and scenario costs
Genetic algorithm Optimization
BMP Placement Results in Town Brook
Basic
Optimal
Nutrient management plans
Crop rotations & nutrient management plans
Crop rotations & contour strip crop
Contour strip crop & nutrient management plans
Riparian forest buffers
None
Same effectiveness - 30% Cost Reduction
Scenario
Total P load (kg)
Fitness score
Scenario cost, $/yr
Cost effectiveness $/kg P removed/yr
Basic
1585 kg
0.99
$78,000
$34
Optimal
1563 kg
1.67
$55,000
$24
Assessment Projects
National USDA project with two major efforts Watershed monitoring and simulation modeling Nov/Dec Journal of Soil and Water Conservation features findings from participating watersheds National assessments for 4 components Cropland, Wetland, Wildlife, and Grazing Land
Conclusions, Recommendations, and Cautions National P Project showed that multi-state collaborative research programs are effective for the development of decision-making tools that help achieve a balance between environmental quality and farm productivity
Conclusions, Recommendations, and Cautions New York City Watershed Agriculture Project showed that voluntary programs can work, but.. Careful coordination among participating government agencies critical Farmer/land owner involvement in process critical Cost-share assistance critical Local benefit must be evident
Conclusions, Recommendations, and Cautions Assessment is challenging Monitoring is expensive and time consuming Attributing inputs or reductions to individual
sources within a watershed is very difficult
Validation of models limited by availability of
measured data Accurate scaling of estimates from plot to field to farm to watershed levels is an evolving science Monitoring should be continued to the extent of
available funding to support and improve modeling efforts
Conclusions, Recommendations, and Cautions Researcher and policy makers should consider the broadest possible range of pollutants and land uses in order to consider trade-offs and all potential impacts when developing and recommending management practices
