Optimization of Whole Farm Nutrient Balance: N-CyCLE. Michel A. Wattiaux 1. 1 Department of Dairy Science, UW-Madison.

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1 Optimization of Whole Farm Nutrient Balance: N-CyCLE Michel A. Wattiaux 1 1 Department of Dairy Science, UW-Madison wattiaux@wisc.edu

2 Background Planning nutrient management: What are the options for producers to maximize export of nutrients in economically valuable products while: minimizing imports of nutrients onto the farm, and minimizing environmental risks? Holistic approach: Need for integrated feeding, cropping and manure management strategies

3 Tool name: N-CyCLE Nutrient-Cycling Crops Livestock Environment Developers: Michel Wattiaux*, Doris Pellerin**, Edith Chabornneau**, Sally A. Flis*, Vinicius R. Moreira* Stage of development: Not released * University of Wisconsin-Madison ** Université de Laval, Quebèc, CN

4 Outline 1. N-CyCLE v Model Objectives and Description 2. Strengths and Limitations 2. N-CyCLE v Conceptual approach of the model 3. N-CyCLE v Inputs, objective functions and constraints, and outputs 2. Example 4. Vision for the future

5 N-CyCLE v.1.0

6 A Simple Model to Optimize Feeding Program and Crop Rotation of Dairy Farms Purchased Feeds Linear programming: ration optimization including crops and purchased feeds Milk Dairy Herd Home-grown Feeds Soil Balance Crops N-Fixation M. A. Wattiaux Proc. Nutr. Mgt Conf Pp rd Babcock Institute Tech. Workshop, University of Wisconsin-Madison

7 Strengths and Limitations of v.1.0 The model was a first successful step in moving from balancing rations to balancing home-grown and purchased nutrients as one unit of management The model objective was to minimize purchased feeds; thus an implicit model assumption was that home-grown feeds were cheaper and were less environmentally threatening than purchased feed The model worked as if the farm was one field and one animal group The model worked on a discrete-year basis (no 2 nd and 3 rd year nutrient credit) The model did not assess economic impact of management decisions in response to changes motivated by excess nutrient imports and related environmental concerns.

8 N-CyCLE v.2.0

9 Modeling Nitrogen Cycling and Balance Purchased / Imported Inputs Feeds Bedding Dairy Herd sub-model Sold / Exported Outputs Milk Animal Feed Harvesting & Storage (Bedding) Water Air Collection & Storage Fertilizer Crops Sub-model Soil Crops

10 Feeds Bedding Modeling Nitrogen Cycling and Balance Purchased / Imported Inputs Dairy Herd sub-model Sold / Exported Outputs Milk Animal Feed Harvesting & Storage (Bedding) Water Air Collection & Storage Fertilizer Crops Sub-model Soil Crops

11 IMPORTS (t/y) N-CyCLE Conceptual Framework EXPORTS (t/y) A Conc. Feed B Forage C Fertilizer D N-Fixed 10 Homegrown Dairy Herd 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y 5: Heifers >1 y Crops Feeds Fields in group 1 Fields in group 2 Fields in group 3 Fields in group 4 Fields in group 5 Liquid Solid E Milk F Animal B Crops G Balance = A + B + C (+ D) -E F B (- G)

12 N-CyCLE 2.0 and Above Purposes: To describe Nitrogen, Phosphorus and Potassium (pools), flows and balances across units of management within a farm Optimization of the whole-farm model: Net income (maximization) P balance (minimization) N balance (minimization) Research and Educational tool: Teaching, Research, Extension Private consultants Documentation: in progress

13 N-CyCLE v.2.0 and Above Developed on Microsoft Excel using: Solver Function that solves linear and integer models by the Simplex algorithm Five worksheets (N-CyCLE v.2.5): Four Input sheets Herd and Rations Feed Land Units and Crop Rotations and Fertilizers Optimization sheet Output sheet

14 Current version N-CyCLE v.2.5

15 IMPORTS (t/y) Herd Description EXPORTS (t/y) A Conc. Feed B Forage C Fertilizer D N-Fixed 10 Homegrown Dairy Herd 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y 5: Heifers >1 y Crops Feeds Fields in group 1 Fields in group 2 Fields in group 3 Fields in group 4 Fields in group 5 Liquid Solid Balance = A + B + C + D - E F B (- G) IMPORTS (lbs/y) A Conc. Feed B Forage C Fertilizer D N-Fixed E Milk F Animal (Meat) B Crops INPUTS G 10 H o m e- gr o w nf ee ds Dairy Herd 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y 5: Heifers >1 y Crops Fields in group 1 Fields in group 2 Fields in group 3 Fields in group 4 Fields in group 5 Liquid Solid EXPORTS (lbs/y) E Milk F Animal (Meat) B Crops G Balance = A ± B + C + D - E F - G

16 Herd Description Herd Structure Herd Production Ration Composition (5 groups) Milk price INPUTS IMPORTS (lbs/y) EXPORTS (lbs/y) A Conc. Feed B Forage Dairy Herd 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y E Milk F Animal (Meat) 10 H o m 5: Heifers >1 y Liquid e- gr Crops Solid C Fertilizer o w nf Fields in group 1 Fields in group 2 B Crops ee ds Fields in group 3 D N-Fixed Fields in group 4 G Fields in group 5 Balance = A ± B + C + D - E F - G

17 Herd Herd Structure: Total # cows Mature body weight Calving interval Culling rate Mortality rate (heifers<1yr) Age at first calving Dairy INPUTS IMPORTS (lbs/y) EXPORTS (lbs/y) Herd A Conc. Feed B Forage 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y E Milk F Animal (Meat) 10 H o m 5: Heifers >1 y Liquid e- gr Crops Solid C Fertilizer o w nf Fields in group 1 Fields in group 2 B Crops ee ds Fields in group 3 D N-Fixed Fields in group 4 G Fields in group 5 Balance = A ± B + C + D - E F - G

18 Herd Production: Herd Peak milk production, Kg/d Fat, % Protein, % Other solids, % Management groups (n 5): 1 or 2 lactating, 1 dry, and 2 heifer groups 1 or 2 lactating, 2 dry, and 1 heifer groups 3 lactating and 2 heifer groups INPUTS IMPORTS (lbs/y) EXPORTS (lbs/y) Dairy Herd A Conc. 1: Hi TMR E Milk Feed 2: Lo TMR B Forage 3: Dry Cows 4: Heifers <1 y F Animal (Meat) Liquid Milk Price C Fertilizer D N-Fixed 10 H o m 5: Heifers >1 y e- gr o w nf ee ds Crops Fields in group 1 Fields in group 2 Fields in group 3 Fields in group 4 Fields in group 5 Solid B Crops G Balance = A ± B + C + D - E F - G

19 Herd Ration Composition: Fiber/Energy Neutral Detergent Fiber (NDF) Forage NDF Non Fiber Carbohydrates (NFC) Nitrogen Rumen Undegraded Protein (RUP) Rumen Degraded Protein (RDP) Minerals P Ca (K + Na) (Cl + S) IMPORTS (lbs/y) A Conc. Feed B Forage C Fertilizer D N-Fixed INPUTS 10 H o m e- gr o w nf ee ds Dairy Herd 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y 5: Heifers >1 y Crops Fields in group 1 Fields in group 2 Fields in group 3 Fields in group 4 Fields in group 5 Liquid Solid EXPORTS (lbs/y) E Milk F Animal (Meat) B Crops G Balance = A ± B + C + D - E F - G

20 Feed (and Bedding) Inputs Feed Composition and Prices (n 20): Home-grown feed (and bedding) defined by crop rotation (n 10) Corn silage, alfalfa silage, grass legume mix, grass silage Corn stover, straw Corn grain, wheat (barley), Soybean (for roasting) Purchased feeds (n 10) Energy sources (e.g. CaFat, WCS) By-products (e.g. CoDi, CGM) RUP and RDP sources (e.g. Sbex, Sbsol, Urea) Minerals (e.g. CaCO 3, Ca 2 PO 4 ) A Conc. Feed B Forage IMPORTS (lbs/y) C Fertilizer INPUTS Dairy Herd 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y 10 5: Heifers >1 y Ho megro wn Crops Fee ds Fields in group 1 Fields in group 2 Fields in group 3 Liquid Solid EXPORTS (lbs/y) E Milk F Animal (Meat) B Crops D N-Fixed Fields in group 4 Fields in group 5 G Balance = A ± B + C + D - E F - G

21 Land Units and Crop Rotations Land Units (n 5): Areas (Distance from facilities) Crop rotations (n 5): User-defined (CCC; SCC; CCAAA; CCCSCAAA; CCCSWAAA) Yield of each crop in each rotation N, P, K requirements Adjusted for Legume credits Soil test P Cost of production ($/ha) Dairy A Conc. Feed IMPORTS (lbs/y) INPUTS Herd 1: Hi TMR 2: Lo TMR EXPORTS (lbs/y) E Milk B Forage 3: Dry Cows 4: Heifers <1 y F Animal (Meat) 10 Ho megro wn Fee 5: Heifers >1 y Crops Liquid Solid C Fertilizer ds Fields in group 1 Fields in group 2 Fields in group 3 B Crops D N-Fixed Fields in group 4 Fields in group 5 G Balance = A ± B + C + D - E F - G

22 (N) Management Type of (Liquid & Solid) Type of Storage Facility Method of Spreading Costs Related to Management INPUTS IMPORTS (lbs/y) EXPORTS (lbs/y) Dairy Herd A Conc. Feed B Forage 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y E Milk F Animal (Meat) 10 Ho megro wn Fee 5: Heifers >1 y Crops Liquid Solid C Fertilizer ds Fields in group 1 Fields in group 2 Fields in group 3 B Crops D N-Fixed Fields in group 4 Fields in group 5 G Balance = A ± B + C + D - E F - G

23 (N) Management Type of & Storage Facility: Liquid Daily Haul Liquid Storage: Covered Uncov. Top Loaded Uncov. Bottom Loaded Solid Bedded Pack Stack Compost IMPORTS (lbs/y) A Conc. Feed B Forage C Fertilizer D N-Fixed INPUTS Dairy Herd 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y 10 5: Heifers >1 y Ho megro wn Crops Fee ds Fields in group 1 Fields in group 2 Fields in group 3 Fields in group 4 Fields in group 5 Liquid Solid EXPORTS (lbs/y) E Milk F Animal (Meat) B Crops G Balance = A ± B + C + D - E F - G

24 (N) Management Method of Spreading: Liquid: Broadcast, no incorporation Broadcast, incorporated within 2h Band spreading Injection in open slots Knifing in Solid: Box spreader, incorporated within 2h Box spreader, no incorporation IMPORTS (lbs/y) A Conc. Feed B Forage INPUTS Dairy Herd 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y 10 5: Heifers >1 y Ho megro wn Crops Fee ds Fields in group 1 Liquid Solid EXPORTS (lbs/y) E Milk F Animal (Meat) C Fertilizer Fields in group 2 Fields in group 3 B Crops D N-Fixed Fields in group 4 Fields in group 5 G Balance = A ± B + C + D - E F - G

25 Management Cost Related to Management: Cost of production ($/t 0) Cost for exporting ($/t 100) Cost of spreading (distance from storage) INPUTS IMPORTS (lbs/y) EXPORTS (lbs/y) Dairy Herd A Conc. Feed B Forage 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y E Milk F Animal (Meat) 10 Ho megro wn Fee 5: Heifers >1 y Crops Liquid Solid C Fertilizer ds Fields in group 1 Fields in group 2 Fields in group 3 B Crops D N-Fixed Fields in group 4 Fields in group 5 G Balance = A ± B + C + D - E F - G

26 Fertilizers Purchased Fertilizers (n=4): User-defined (e.g.: ; ; ; ) Nutrient contents (N, P & K) Market prices Variable spreading costs per Land Unit INPUTS IMPORTS (lbs/y) EXPORTS (lbs/y) Dairy Herd A Conc. Feed B Forage 1: Hi TMR 2: Lo TMR 3: Dry Cows 4: Heifers <1 y E Milk F Animal (Meat) 10 Ho megro wn Fee 5: Heifers >1 y Crops Liquid Solid C Fertilizer ds Fields in group 1 Fields in group 2 Fields in group 3 B Crops D N-Fixed Fields in group 4 Fields in group 5 G Balance = A ± B + C + D - E F - G

27 Objective Functions To find the best combination of: Rotations for each of the pre-defined land units, allocation and fertilizer application, Diets ingredient mix for each pre-defined group of animals, with the objective to either: maximize net income ($), or minimize whole farm phosphorus balance (kg/yr), or minimize whole farm nitrogen balance (kg/yr) 3.0- Optimization functions 3.1- Net income, $ 75,917 Environmental cost 3.2- P balance, kg 4, $/kg 3.3- N balance, kg (w/o fixation, manure export) 24, N balance, kg (w/o manure export) 32, $/kg 3.4- Energy used, MJ 215,069,391 0$/MJ 3.5- Combined Index, $ -675,090 Optimization worksheet

28 Land Use: Land / Crop Constraints (Land available - cropped area) 0 (i.e., crop required land only) = 0 (i.e., crop all available land) Crop rotation Assignment: crop sold user defined limit If binary constraint: one rotation per field If no binary constraint: fractional rotation per field is allowed Crop requirements: Optimization worksheet 0 (N, P, K supplied - N,P,K needed) Legal limits Agronomic limits

29 Feed / Herd / Constraints produced - manure used (manure exported) = 0 Nutritional Need (per animal group basis) Min < Total amount of DM < Max Min < NDF, NFC, Absorbable P, Absorbable Ca < Max Min < FNDF, RUP, RDP, and K CP < Max Adjustable Losses Home-grown (Field and storage losses) Purchased feed (Shrinkage losses) Adjustable feed refusals Optimization worksheet

30 Outputs Main Outputs: Income ($) P balance (kg/yr) N balance (kg/yr) Optimal rotation: w/ binary constraint: One of the five rotation for each land unit w/o binary constraint: Acres of each selected crop as a fraction of the cropland of the farm

31 Model Outputs Crop Fertilization plan: Type and amount of purchased fertilizer and manure to apply on each land unit Amount of manure to export (if allowed) Feeding program: Type and amount of purchased feed and home-grown feed to offer each animal group Amount of home grown feed to sell (if allowed)

32 N-CyCLE 2.5 Example

33 Scenario ha (50; 50; 50; 42.4 ha) with high soil P test 190-cow herd producing 10,000kg/lactation Hi group Lo group Far-off Pre-fresh 153 Heifers Rotations CS-CG-CG Soybean-CS-CG CS-CG-Alfalfa-Alfalfa-Alfalfa CS-CG-CS-Soybean-CG-Alfalfa-Alfalfa-Alfalfa CS-CG-CS-Soybean-Wheat-Alfalfa-Alfalfa-Alfalfa

34 N-CyCLE Output Farm description Outputs: 1.0. Indicators 1.1. Animal units (AU) 385 AU Early 97 AU Mid-Late 136 AU Far-Off 25 AU Prefresh 14 AU Heifers 113 AU 1.2. Area available ha Land Unit ha Land Unit ha Land Unit ha Land Unit ha Milk output Economics Balances { { 1.3. Animal Density 2.0 AU/ha 1.4. Milk sold/year kg/year Milk sold/ha/year 6681 kg/ha/year 1.5. Net income, $ $ 75, /year Milk income, $ $ 382, /year Animals sold, $ $ 50, /year Crop income, $ $ 34, /year Total income, $ $ 468, /year Feed costs, $ $ 197, /year Milk+Animal income over Feed costs, $ $ 2.19 Net over Total income, % 16.2 % 1.6. Nutrient Balances P Balance N Balance (w/o fixation and manure export) N Balance (w/o manure export) kg/year kg/year kg/year

35 N-CyCLE Output Rations: Feeds Outputs: 2.0. Rations Rations ingredients (%DM): Group 1 Group 2 Group 3 Group 4 Group 5 CoSi AlSi SBw 1.92 CoGr Stover CaFat 1.05 Sbsol CGM 5.67 CoDi Urea Ca-C DiCa-P Total Nutrient Composition 2.1. Rations Compositions: Group 1 Group 2 Group 3 Group 4 Group 5 DE1x (Mcal/t DM) FNDF, (% DM) NDF, (% DM) NFC, (% DM) CP, (% DM) RUP, (% DM) RDP, (% DM) Ca, (% DM) P, (% DM) K, (% DM) Mg, (% DM) Na, (% DM) Cl, (% DM) S, (% DM) DCAD (meq/kg) Energy used (MJ/t DM) Price, $/t DM $93.39 $89.64 $51.25 $77.30 $65.14 Storage costs, $/t DM $24.77 $22.77 $25.66 $16.00 $27.88 F:C ratio

36 N-CyCLE Output Allocations: Rotation Fertilizer Outputs: 3.0. Rotations, Fertilizer and application tons/year Purchased Inorganic Fertilizer Application Land Unit Rotation Solid Liquid Land Unit 1 CCC Land Unit 2 CCC Land Unit 3 CCC Land Unit 4 CCAAA Total

37 Net income $ when maximizing Net income, minimizing P or N balances Net income (US$/year) $80,000 $60,000 $40,000 $20,000 $0 190 cows (2.0 AU/ha) 190 cows (2.0 AU/ha) Max Net income Min P balance Min N balance $76,000 $30,302 $33,139 Lost income When P was minimized: = $95 / kg When N was minimized: = $25 / kg

38 Income and Balances When Maximizing Income or Minimizing Balances Objective Function Maximize Income, $ Minimize P Balance, kg Minimize N Balance, kg Income, $ 76,000 30,303 33,199 P Balance, kg 4,158 3,676 5,798 N Balance*, kg 32,211 34,710 30,509 * export not allowed

39 Rotations and Purchased Feed when Maximizing Net income, Minimizing P and N balances Maximizing Net income CCC; CCC; CCC; CCAAA Sbw, Sbsol, CGM, CoDi, Urea, CaFat, Ca 2 PO 4, CaCO 3, (298.4 ton/year) Minimizing P balance CCC; CCC; CCC; CCCSCAAA Sbex, Sbsol, CGM, Soyhulls, Cotton, Urea, CaFat, Ca 2 PO 4 (424.8 ton/year) Minimizing N balance CCC; CCC; CCC; CCAAA Sbex, Sbsol, CGM, Soyhulls, Cotton, Wheat, Straw, Urea, CaFat, Ca 2 PO 4 (551.5 ton/year)

40 Summary N-CyCLE v.2.5 provides an economic evaluation of management practices including those related to environmental management of farms What is the cost/benefit of reducing N balance? What is the cost/benefit of reduction P balance? N-CyCLE v.2.5 provides a mean to compare current practices to an optimal set of Best Management Practices

41 Summary and (near) Future N-Cycle allows: Land use studies Land requirement for different crop rotation systems Land requirement for farm of increasing animal density Sensitivity analyses Change in feed or fertilizer market prices on feeding and cropping strategies Change in BMP to maintain high N/P ratio in manure Forage quality Quantify losses and soil build-up Long term change in Soil test P Ammonia-N losses Evaluation of the economic impact of regulatory policies Limit P balance Limit Ammonia Loss

42 Limitations Input intensive/knowledge intensive Not (yet) user friendly Limited usage Require additional validation Inherent limitation of Linear programming Everything is linear How can economies of scale be built in a linear programming? Incomplete estimates of environmental losses N leaching Garbage in, Garbage out

43 Milk/Livestock Sold Sold Crop Sold Nutrient - Cycling Crops - Livestock - Environment Purchased Feed Purchased Fertilizer/ Stored Feed Livestock Environment (air & water) Fixed N Soil Crops Pasture