The effects of land-use on water quality are more obvious in places like Spring Green because of the susceptible geologic conditions

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1 Why are we here? Developing strategies to utilize nitrogen more efficiently improves profitability and reduces amount of nitrate that would otherwise up in groundwater and surface waters The effects of land-use on water quality are more obvious in places like Spring Green because of the susceptible geologic conditions Tangible costs associated low nitrogen use efficiency: Costs of nitrogen itself Cost of water treatment to remove agricultural chemicals that cause health effects. Municipal Water Supplies Private wells Costs of disposing of locally produced nitrogen sources (i.e. manure, bio-solids, industrial sludge) while importing industrially produced nitrogen from out of state.

2 Nitrogen Fertilizer Pricing Form Cost per ton Cost per lb of nitrogen Anhydrous Ammonia (82% N) $783 $0.48 Nitrogen Solutions (30% N) $373 $0.62 Urea (44-46% N) $554 $0.62 Ammonium Nitrate (35% N) $506 $0.73 Sulfate of Ammonium (21% N) $451 $1.07 Source: Agricultural Prices for March 2012, National Agricultural Statistics Service, USDA.

3 Price ($ per lb of nitrogen) Nitrogen Fertilizer Costs ( ) Anhydrous ammonia Nitrogen solutions (30%) Urea 44-46% nitrogen Ammonium nitrate Sulfate of ammonium As energy prices go, so to do nitrogen fertilizer costs. As the price of nitrogen fertilizers increase, it becomes increasingly important to improve nitrogen use efficiency to maximize profitability and reduce our dependence on fossil fuels

4 How much nitrogen does it take to raise groundwater nitrate 1 ppm? The actual amount will vary based on the amount of recharge. For Wisconsin this is likely somewhere between 6 and 10 inches depending on where you live. For Spring Green we will assume that nitrogen not taken up by the plant will mineralize and nitrify. 8 in. 10 mg NO 3 -N 43,560 ft 2 1 ft liters 1 g 1 kg 2.2 lbs liters 1 acre 12 in. 1 ft mg 1000 g 1 kg = 18.1 lbs N per acre Nitrate-Nitrogen Concentration (mg/l) N Inches of Recharge lbs of Nitrogen per acre

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6 Nitrate Concentration Generalized Nitrate Leaching Potential 0 Forest/ Prairie/ CRP Economic Optimal Nitrogen Rates Alfalfa Soybean Corn Potato Corn- Soybean Masarik, UW-Extension

7 Nitrate Concentration Generalized Nitrate Leaching Potential 0 Forest/ Prairie/ CRP Economic Optimal Nitrogen Rates Alfalfa Soybean Corn Potato Corn- Soybean Masarik, UW-Extension

8 Nitrate Concentration GW NO3-N = f(crop N Requirements, Excess N, Soils, Geology) 0 Forest/ Prairie/ CRP Economic Optimal Nitrogen Rates Alfalfa Soybean Corn Potato Corn- Soybean Masarik, UW-Extension

9 Nitrate Concentration Water Quality/ Nitrate Concentration Good Poor UW Nitrogen Guidelines get us to a baseline Level of nitrate concentration in groundwater 0 Forest/ Prairie/ CRP Economic Optimal Nitrogen Rates Alfalfa Soybean Corn Potato Corn- Soybean Masarik, UW-Extension

10 Water quality as a function of crop N recommendations No Inputs Water Quality/ Nitrate Concentration Good Poor Medium Inputs Amount of nitrogen applied High Inputs

11 Water quality as a function of watershed area in production of a high input N crop 0% 50% Percent of land base in production 100% Water Quality - Nitrate Concentration Low High

12 Water quality as a function of Nitrogen Use Efficiency Studies show efficiency typically about 30-50% (Cassman et. al. 2002) Less nitrogen than economic optimal results in the same or greater yield. Baseline or Reference Condition Research based economic optimal nitrogen application Increased nitrogen application results in increased yield but nitrogen use efficiency decreases. Economic optimal nitrogen application results in greater yield. Increased nitrogen application results in increased yield without an increase in efficiency. Less Amount of N loss More Water Quality - Nitrate Concentration Less More

13 Factors affecting nitrogen loss to groundwater Within our control Limited control Out of our control Amount of nitrogen applied As a function of crop type Nitrogen application rate relative to economic optimum Percent of land base in production Nitrogen use efficiency Geology Soil Type Precipitation / Climate

14 *Strategies to Reduce Nitrate Leaching to Groundwater on Sandy Soils Strategic reduction acreage Reduce Nitrogen Input Needs Investigate ability of these practices to increase nitrogen-use efficiency Create groundwater protection zones around municipal or residential wells Convert agricultural acreage on edges of fields into windbreaks or grasses Increase acreage of crops with lower nitrogen requirement Modify rotations so that the nitrogen mass balance is able to meet the drinking water standard for a 4 year period No fall application of manure or fertilizer Cover crop management for nitrogen efficiency Slow release fertilizer (Polymer coated urea) Split applications *Assuming that all fields are already voluntarily following Nutrient Management plans, applying nitrogen only at economic optimal rate, and crediting all nitrogen sources.

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17 Additional References Cassman, Kenneth G.; Dobermann, Achim R.; and Walters, Daniel T., "Agroecosystems, Nitrogen-use Efficiency, and Nitrogen Management" (2002). Agronomy -- Faculty Publications. Paper Dinnes, Dana L.; Karlen, Douglas L.; Jaynes, Dan B.; Kaspar, Thomas C.; Hatfield, Jerry L.; Colvin, Thomas S.; and Cambardella, Cynthia A., "Review and Interpretation: Nitrogen Management Strategies to Reduce Nitrate Leaching in Tile-Drained Midwestern Soils" (2002). Publications from USDA-ARS / UNL Faculty. Paper Nitrate Nitrogen in Surface Waters as Influenced by Climatic. Conditions and Agricultural Practices. Gyles W. Randall* and David J. Mulla J. Environ. Qual. Weed, D.A.J., and R.S. Kanwar Nitrate and water present in and flowing from root-zone soil. J. Environ. Qual. 25: WI Well Water Quality Viewer. Center for Watershed Science and Education. Brye, K.R. and J.M. Norman, L.G. Bundy, and S.T. Gower Nitrogen and Carbon Leaching in Agroecosystems and Their Role in Denitrification Potential. J. Environ. Qual. Vol. 30 No. 1, p