Phosphorus Fertilizer Decisions

Transcription

1 Phosphorus Fertilizer Decisions Tom Bruulsema, Phosphorus Program Director Malcolm Stambaugh, Crop Specialist & Stewardship Advocate Alan Madison, Producer & Stewardship Advocate

2 The International Plant Nutrition Institute is supported by leading fertilizer manufacturers. Its mission is to promote scientific information on responsible management of plant nutrition.

3 4R: right means sustainable

4 As a sustainability system, 4R Nutrient Stewardship needs METRICS.

5 Nutrient Stewardship Metrics for Sustainable Crop Nutrition Enablers (process metrics) Outcomes (impact metrics) Extension & professionals Infrastructure Research & innovation Stakeholder engagement Actions (adoption metrics) [Require regional definition of 4R] Cropland area under 4R (at various levels) 1. Farmland productivity 2. Soil health 3. Nutrient use efficiency 4. Water quality 5. Air quality 6. Greenhouse gases 7. Food & nutrition security 8. Biodiversity 9. Economic value

6 4R Outcome Metrics are influenced by 4R and more.

7

8 Adaptive Management addresses 4R metrics at scales ranging from farm to global.

9 4R adaptive management involves decision cycles. Policy Level Regulatory, Infrastructure, Product Development Regional Level Agronomic scientists, Agri-service providers Farm Level Producers, Crop advisers DECISION SUPPORT based on scientific principles Recommendation of right source, rate, time, and place (BMPs) DECISION Accept, revise, or reject ACTION Change in practice EVALUATION by METRICS Cropping System Sustainability Performance LOCAL SITE FACTORS Climate Policies Land tenure Technologies Financing Prices Logistics Management Weather Soil Crop demand Potential losses Ecosystem vulnerability

10 Phosphorus Metrics Farmland productivity Phosphorus use efficiency Soil health

11 Phosphorus Use Efficiency in Corn & Soybeans 1) Trend driven by yield 2) Does not include manure Calculated from USDA-NASS and USDA-ERS data

12 Wheat Yields increasing, but not as fast as those of corn. Phosphorus use efficiency increasing only recently, into the mining range. Calculated from USDA-NASS and USDA-ERS data

13 PUE: Ratio of removal to use varies across US cropland 2011

14 Long-term, a lot of crop yield is attributed to P. 60% N+P 27% P One example: Long-term contribution of P to yield of irrigated corn in Kansas 40-year average, (Stewart et al., 2005, Agron. J. 97:1 6)

15 How much crop yield can be attributed to P in the short term (one year)? Expected to be zero, or very small, on soils with adequate P levels When soil test P is below critical levels: ~15% (0-23%) for soy ~20% (0-30%) for corn ~40% (10-50%) for wheat, oats, alfalfa and clover in Illinois (Figure 8.5, Illinois Agronomy Handbook)

16 Illinois soil test P declined from 2001 to : 39% of soils below critical 20% optimal >50 Bray and Kurtz P1 soil test, ppm

17 Phosphorus legacy differs by region (11) (23) (38) (Olsen)

18 Phosphorus Metrics Water Quality

19 Western Lake Erie watershed: dissolved P losses increasing 40% reduction target GLWQA Annex Nutrients Committee, May David Baker & Laura Johnson, National Center for Water Quality Research, Tiffin, OH. Cropland data from IPNI NuGIS.

20 Dissolved phosphorus trends, 1993 to 2004 Lorenz, D.L., Robertson, D.M., Hall, D.W., and Saad, D.A., 2009, U.S. Geological Survey Scientific Investigations Report

21 USEPA National Rivers and Streams Assessment : A Collaborative Survey 41-54% poor, but % good > % fair

22 St. Louis in the center of total phosphorus loss. SPARROW Robertson and Saad (2013)

23 Summary 4R Phosphorus Decisions 1. 4R with metrics is a sustainability system 2. Metrics guide farm level phosphorus decisions 3. Metrics represent stakeholder interest 4. 4R metrics aggregated enhance public understanding 5. 4R phosphorus metrics come in complementary sets, balancing at least all of: Farmland productivity (yield) Phosphorus use efficiency Soil phosphorus status (soil health) Water quality