Institute of Ag Professionals Proceedings of the 2012 Crop Pest Management Shortcourse & Minnesota Crop Production Retailers Association Trade Show www.extension.umn.edu/agprofessionals Do not reproduce or redistribute without the written consent of author(s).
Taking the Long View Are Nutrients being Mined from Customer Fields? Paul E. Fixen Sr. Vice President, IPNI pfixen@ipni.net The 4Rs and Nutrient Management Minnesota Crop Pest Management Short Course & Trade Show December 11, 2012
A rather simple question Fertilizer applied Recoverable manure Removal by crop harvest Partial nutrient balance Farm records Manure analysis Standard tables Grain or forage analysis
Is the answer to the balance question important?
Stakeholders define goals Resource use efficiencies: Energy, Labor, Nutrient, Water Soil erosion Nutrient balance Yield Net profit Biodiversity Nutrient loss Managers choose practices Water & air quality Affordable & accessible food Ecosystem services Farm income Return on investment Quality Yield stability Working conditions
Hypothetical P balance example 200 bu/a continuous corn (removal = 60) Nutrient use efficiency P 2 O 5 applied Nutrient balance Quantity Ratio Soil fertility change Typical 1 yr recovery efficiency lb/a lb/a Rem/use % LOW 120 +60 0.50 Increase <10 60 0 1.0 Minimal 15-20 HIGH 30-30 2.0 Decrease >25 Which rate is 4R? Would depend on: Soil test levels Source, time and place System objectives
Change in median soil P level for 12 Corn Belt states as related to state P removal to use ratio, 2005-2009. Change in median P, ppm 2 0-2 -4-6 -8-10 SD MN KS KY MO NE OH IA IN MI y = -18.99x + 17.8 R² = 0.86-12 WI -14 0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 P Removal to use ratio* R/U of 0.935 = 0 change in soil P (7% more than removal) IL *NuGIS 1/12/2012.
P balance and soil test levels in MT, ND, and SD (NuGIS, 1/12/2012) Median Bray P, ppm P removal/use* ratio State 2001 2005 2010 2002 2007 Average MT 12 14 14 0.97 1.04 1.01 ND 10 11 11 1.07 0.94 1.01 SD 11 14 13 1.02 0.91 0.97 MN 16 18 18 0.93 0.93 0.93 * Use = Fertilizer P applied plus recoverable manure P. Replacing P removed in harvested portions of crops maintained soil P as indicated by soil tests
Graph from Randall, 2010 70% of uptake typically comes from bulk soil
What is it? NuGIS what and why? A model that, on a county and watershed scale, estimates partial nutrient balance for N, P & K as interactive thematic maps or tables Does not replace field or farm specific estimates Why was it developed? To facilitate 4R nutrient stewardship decisions To serve as a resource for nutrient management education To guide marketing of nutrient products and services To improve environmental modeling http://www.ipni.net/nugis
Methods basic model Basic model: a simple partial nutrient balance algorithm Farm fertilizer 1987 to 2007 in 5-yr increments set by Census of Agriculture (COA) Recoverable manure Removal by crop harvest Partial nutrient balance Biological N fixation
Methods Farm Fertilizer AAPFCO commercial farm fertilizer sales data when available When county AAPFCO unavailable, state total apportioned to counties using COA fertilizer and lime expenditures When fertilizer for farm purposes not reported, USGS (Ruddy) method used County sales data smoothed to better represent use
Corn and soybean nutrient removal coefficients used in NuGIS relative to past constants Crop-nutrient (lb/bu) IPNI, 2010* NuGIS** Change,% Corn N 0.90 0.67-26 Corn P 2 O 5 (West, Central, East) # 0.38 0.30, 0.35, 0.40-21 to +5 Corn K 2 O 0.27 0.25-7 Soybean N 3.80 3.25-14 Soybean P 2 O 5 0.84 0.73-13 Soybean K 2 O 1.30 1.18-9 * Central tendency of Corn Belt Extension publications. **Based on database of measured vales (M. Nathan). # West of WI, IL, MO, AR, LA; Other states; East of OH, KY, TN, GA. Corn, P 2 O 5
http://www.ipni.net/article/ipni-3295
The Apps Age?
IPNI Nutrient Removal App iphone/ipad Available in 1 st quarter 2013 Will also convert grain analysis to removal coefficients Suggestions welcome
Interactive Graphics http://www.ipni.net/nugis 3,117 counties 2,150 8-digit hydrologic units 18 Hydrologic regions
Nutrient removal to use N P K Removal/use* ratio State 1987 1992 1997 2002 2007 Average US 0.74 0.73 0.75 0.78 0.77 0.75 MN 0.74 0.73 0.78 0.88 0.84 0.79 US 0.74 0.73 0.75 0.78 0.77 0.75 MN 0.82 0.82 0.89 0.93 0.93 0.88 US 0.74 0.73 0.75 0.78 0.77 0.75 MN 1.04 1.05 1.24 1.34 1.10 1.15 * Use = Nutrients in applied fertilizer plus recoverable manure plus legume N; NuGIS, 1/12/2012.
P removal to use ratio, 2007 by watershed
K removal to use ratio, 2007
Change in K 2 O balance over 20 years 1987 2007
N removal to use ratio, 2007
Future of NuGIS Estimation for non-census years Continued refinement of nutrient removal coefficients Incorporation of estimates for deposition, biosolids, soil erosion Mobile phone app for growers
My NuGIS: Improving Nutrient Stewardship
State County Local watershed
Interpretation Discussion of field balance relative to region and implications 4R Recommendations Balance estimates trigger suggested practices from a master list of BMPs iphone/ipad Available in 2014, budget permitting Suggestions welcome
Are Nutrients being Mined from Customer Fields? It s a good question especially if you are taking the long view