4R Nitrogen Management to Increase N Use Efficiency and Reduce N Losses. David Burton Department of Plant, Food, and Environment

Transcription

1 4R Nitrogen Management to Increase N Use Efficiency and Reduce N Losses David Burton Department of Plant, Food, and Environment 1

2 The Objective of N Fertilization Soil Fertility The objective in an N fertilization program is to realize the economically optimum yield.

3 The Objective of N Fertilization Soil Fertility The objective in an N fertilization program is to realize the economically optimum yield. Nutrient Management The objective in an N fertilization program is to not only realize the economically optimum yield but to also minimize environmental impacts.

4 To improve nutrient management the fertilizer industry has developed the framework of 4R management IPNI, 2015

5 The Objective of N Fertilization Soil Fertility The objective in an N fertilization program is to realize the economically optimum yield. Nutrient Management The objective in an N fertilization program is to not only realize the economically optimum yield but to also minimize environmental impacts. Soil Health Management The objective in an N fertilization program is to not only realize the economically optimum yield but to also minimize environmental impacts and sustain the resource.

6 6

7 But, all is not well How did we get here? 7

8 The Plough The plough revolutionized agriculture! It provided a uniform seed bed, controlled weeds and released nutrients for plant growth. But ploughing the soil degrades soil organic matter releasing nutrients to support plant growth Organic matter is more than just nutrients As with any stock, it can be depleated. 8

9 Fertilization Justus von Liebig - Plants could grow on minerals alone Fritz Haber and Carl Bosch discovered how to make reactive nitrogen from the air the basis of N fertilizer Together they gave rise to the green revolution But you can have too much of a good thing humanity has doubled the reactive nitrogen on the planet! 9

10 National Geographic, 2013

11 Atlantic Soil Health Lab 11 11

12 Cropping System and Nitrogen Mineralization 12

13 To improve nutrient management the fertilizer industry has developed the framework of 4R management IPNI, 2015

14 4R Frame work builds on science and offers practical solutions IPNI, 2015

15 Right Source Balanced supply of nutrients and recognize synergies Use of sources that are (or will become) plant available Ammonium (NH 4+ ) based sources are less likely to be lost than nitrate (NO 3- ) Use of enhanced efficiency fertilizer products Urease and nitrification inhibitors Coated N sources Organic N sources animal manures, biosolids, composts

16 Right Time Attempt to synchronize N availability with plant N demand Applying all at or before planting increases risk of N loss Can improve synchrony of N supply by Delaying nitrification NH 4+ less likely to be lost than NO - 3 Using urease or nitrification inhibitors Banding of N fertilizer to inhibit nitrification Coated products Application of N to cold soils delays nitrification Split applications of N Side-dress applications Foliar applications & fertigation

17 Right Place Right place refers to placement of fertilizer with respect to the seed Sub-surface placement to reduce NH 3 losses Sub-surface placement to reduce N 2 O loss (does not always work) Banding to reduce nitrification and delay NO 3- production to reduce leaching and N 2 O loss Also placement within the landscape Precision farming place the N according to yield expectations Avoid areas of high risk of NO 3- loss and/or N2O emissions IPNI, 2015

18 Right Rate Need to emphasize realistic yield goals and resultant plant nutrient demand Use the other R s to predict and improve nutrient use efficiency Assess soil nitrogen supply Credit manure and legume N sources N rate influences plant yield, economic return and environmental impact differently

19 Plant Response to N Application Fertilizer N Application (kg N/ha)

20 Economic Return of N fertilization

21 Environmental N Impacts of N fertilization

22 Right Rate Need to emphasize realistic yield goals and nutrient use efficiency One of the tools to help us assess nutrient use efficiency is calculating a partial nutrient balance

23 Partial Nitrogen Balance for Corn Yield Goal (8.3 tonnes) N Fertilizer (kg N/ha) Crop N Removal (kg N/ha) Partial N Balance Fertilizer N Use Efficiency (%) %

24 Partial Nitrogen Balance for Corn Yield Goal (8.3 tonnes) N Fertilizer (kg N/ha) Crop N Removal (kg N/ha) Partial N Balance Fertilizer N Use Efficiency (%) % Yield Goal (45 tonnes) N Fertilizer (kg N/ha) Soil Nitrogen Supply (kg N/ha) Crop N Removal (kg N/ha) Residue and Root N return (kg N/ha) Partial N Balance N Use Efficiency (%) %

25 Partial Nitrogen Balance for Potato Yield Goal (45 tonnes) N Fertilizer (kg N/ha) Crop N Removal (kg N/ha) Partial N Balance Fertilizer N Use Efficiency (%) %

26 Partial Nitrogen Balance for Potato Yield Goal (45 tonnes) N Fertilizer (kg N/ha) Crop N Removal (kg N/ha) Partial N Balance Fertilizer N Use Efficiency (%) % Yield Goal (45 tonnes) N Fertilizer (kg N/ha) Soil Nitrogen Supply (kg N/ha) Crop N Removal (kg N/ha) Residue and Root N return (kg N/ha) Partial N Balance N Use Efficiency (%) %

27 Tools to Improve Nitrogen Management in Atlantic Canada David Burton Department of Plant, Food, and Environment 27

28 The Importance of nitrogen management in Prince Edward Island Potato production contributes 10% of PEI s GDP Province 100% dependent on groundwater Concern regarding nitrate impacts PEI also has a significant shellfish industry Concern regarding N impacts on estuaries Need for improved N use efficiency in potato production systems to meet economic and environmental goals A NERP could contribute to improving N use efficiency reducing N 2 O emissions and nitrate leaching

29 In collaboration with AAFC Bernie Zebarth, Judith Nyiraneza PEI Department of Agriculture Kyra Stiles PEI Potato Board Ryan Barrett Fertilizer Canada & Genesis Crop Systems Steve Watts Kensington North and East Prince Watershed groups

30 Tools to increase N use efficiency in Atlantic Canada Need to consider all sources of N. Therefore we need tools to measure all sources of N: soil N supply (SNS), climate impacts on N mineralization potential for N loss Nitrate Exposure Residual Soil N Manure N Environmental Controls SNS Test Crop Residue N Water Function Soil Properties Temperature Function SNS = Soil Nitrogen Supply N o = N Mineralization Potential Biological N Supply Farm Inputs Soil Organic N No & Nitrogen Mineralization Function Soil and Climatic Controls Source 4R Fertilizer Management Timing Rate Placement Soil Mineral N Plant Available N Nitrate Exposure Outputs Crop Yield Residual Soil Nitrate Direct N2O emissions Nitrate Leaching Indirect N2O emissions

31 Measuring soil nitrogen supply Manure N Crop Residue N Soil Organic N In Atlantic Canada high potential for over-winter nitrate loss makes the mineralization of N during the growing season an important N source SNS Test We do not currently measure the N supplying capacity of the soil Soil Mineral N Plant Available N Can a simple, practical test be developed and implemented in regional soil test labs?

32 Can we measure Soil N Supply? Soil Nitrogen Supply (SNS) test Dilute Salt Solution (0.01 M CaCl 2 ) Dilute Salt Solution (0.01 M CaCl 2 ) Air Dry Soil NH 4+ + NO 3-2 week aerobic incubation NH 4+ + NO 3 - Residual Soil Mineral N Biological N Flush

33 Is there significant variation in soil N supply in PEI soils?

34 Soil mineral N content changes from fall to spring

35 Biological N flush is more constant from fall to spring

36 Spatial variation in biological N flush

37 Soil Properties (Total N and N flush) and climate data (air temperature and precipitation) can be used to predict N mineralization Manure N Crop Residue N Soil Organic N SNS Test Water Function Soil Properties Temperature Function No & Nitrogen Mineralization Function Soil Mineral N Plant Available N Leads to a better understanding the impact of soil properties and climate on soil N supply

38 Considerable farm-to-farm variation in estimated N mineralization

39 Assuming 30 cm depth Measures of N supply (kg N ha -1 ) by region Region Biological N o 1 N min N Flush kg N ha -1 Western ab 75 ab Central West a 77 a Central East ab 79 ab East b 68 b Significant range in values between farms... 4R opportunity! N mineralized over 130 days (N min ) ranged from kg N ha -1

40 Estimated nitrogen mineralized over 130 days

41 Estimated nitrogen mineralized over 130 days

42 Measuring the Potential for N Loss Need a means of practically measuring the potential for N loss N 2 O emissions Nitrate leaching Can assess how well management is doing in reducing nitrate accumulation Feedback to producer Documentation of success of mitigation strategies Soil Mineral N Plant Available N Nitrate Exposure Outputs Crop Yield Residual Soil Nitrate Direct N2O emissions Nitrate Leaching Indirect N2O emissions

43 Agri-Environmental Indicators Residual Soil Nitrogen

44 Partial Nitrogen Balance for Potato Yield Goal (45 tonnes) N Fertilizer (kg N/ha) Crop N Removal (kg N/ha) Residual Soil N 36 Fertilizer N Use Efficiency (%) 80% Yield Goal (45 tonnes) N Fertilizer (kg N/ha) Soil Nitrogen Supply (kg N/ha) Crop N Removal (kg N/ha) Residue and Root N return (kg N/ha) Residual Soil N 61 N Use Efficiency (%) 59%

45 Nitrate Exposure Nitrate Exposure (NE) is a temporally integrated measure of the exposure of the soil microbial community to NO 3 - NE n i 1 [NO 3 ] i * d i 1 d i 1 2 An extensive variable May be an emergent property It measures the exposure of plant to nitrate and the potential for loss to the environment Nitrate Exposure time

46 Nitrate Exposure and N 2 O Emissions Atlantic Canadian Cropping Systems 12 Cumulative N2O Emissions (kg N/ha) R² = 0.99 R² = 0.85 R² = 0.19 R² = 0.88 R² = 0.29 Potato 2002 Burton et al Potato 2003 Burton et al Barley 2003 Zebarth et al. 2008a Barley 2004 Zebarth et al. 2008a Barley 2005 Zebarth et al. 2008a Corn 2004 Zebarth et al. 2008b Corn 2005 Zebarth et al. 2008b R² = R² = Nitrate Exposure (gn d/kg soil)

47 Nitrate Exposure and N 2 O Emissions North American Cropping Systems

48 Tools to increase N use efficiency in Atlantic Canada Farm Inputs Need tools to: measure soil N supply (SNS), predict climate impacts on N mineralization, measure potential for N losses Nitrate exposure Residual soil nitrogen Recognize and value increased NUE Manure N Environmental Controls SNS Test Crop Residue N Water Function Soil Properties Temperature Function Soil Organic N SNS = Soil Nitrogen Supply N o = N Mineralization Potential Biological N Supply No & Nitrogen Mineralization Function Soil and Climatic Controls Source 4R Fertilizer Management Timing Rate Placement Soil Mineral N Plant Available N Nitrate Exposure Outputs Crop Yield Residual Soil Nitrate Direct N2O emissions Nitrate Leaching Indirect N2O emissions

49 Current 4R Evaluations in PEI 4R evaluations in side-by-side trials in producer fields In collaboration with 4R Island Measuring GHG Emissions, soil N supply and nitrate exposure Evaluation of foliar urea as a more effective means of supplying in season N application Reduce spring N application Apply additional N in season as part of pesticide application as needed

50 Role of a Nitrous oxide Emissions Reduction Protocol (NERP) 4R Nutrient Stewardship provides climate-smart agricultural practices that reduce N 2 0 emissions for farmers A NERP values and documents these practices Encourages adoption of 4Rs to increase N use efficiency and meet environmental objectives Provide incentive for producers to adopt and monitor the success of 4R strategies Emphasizes the importance of resource monitoring and maintenance = sustainability

51 This research has been supported by...