How much nitrogen is in a healthy Iowa soil from 0-45?

Transcription

1 How much nitrogen is in a healthy Iowa soil from 0-45? a lbs per acre c lbs per acre b lbs per acre d lbs per acre

2 How much nitrogen is in a healthy Iowa soil from 0-45? a lbs per acre c lbs per acre b lbs per acre d lbs per acre

3 Courtesy Stuart Holmes

4 World Population (billions) Haber-Bosch Process Invented Ammonia-N Synthesis (Tg y -1 )

5 World Population (billions) Haber-Bosch Process Invented Ammonia-N Synthesis (Tg y -1 )

6 By Dr. Lyle Conrad - Centers for Disease Control and Prevention, Atlanta, Georgia, USA Public Health Image Library (PHIL); ID: 6901http://phil.cdc.gov/, Public Domain,

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12 Corn Grain Harvest (~100 lbs N/acre/year) Corn Residue Return (~65 lbs N/acre/year) Corn Nitrogen Cycling & 177 bushels Corn Nitrate Use (~165 lb N/acre) Gaseous Loss (~10 lbs N/acre/year) Fertilizer to Corn (~150 lbs N/acre/year) Native Soil Organic Matter Nitrogen ~ 10,000 lb N/acre Microbial production of nitrate from native soil ( lbs N /acre/year) Microbial re-uptake of nitrate ( lbs N/acre/year) NITRATE Nitrate leaching to water (~30 lbs N/acre/year)

13 Is N fertilizer bad for soil health? Is N fertilizer bad for water quality?

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16 Is N fertilizer bad for soil health? Is N fertilizer bad for water quality? Can we have it all? Yield, healthy soil and water quality?

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18 If the soil is: under-fertilized, over-fertilized, or optimally-fertilized for more than a decade, does it affect soil health?

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20 Average optimum N rate Red = corn-soybean (only corn receives N; no effect of N rate to corn on bean yield, which is shown in red squares) Blue = corn-corn

21 Nitrogen fertilizer is critical for soil health All responses from previous slide scaled as a percent of the optimum rate at each site

22 Nitrogen fertilizer is critical for soil health Is it bad for water quality?

23 To understand the role of N fertilizer in water quality challenges, we need to know where the nitrate comes from

24 Corn Grain Harvest (~100 lbs N/acre/year) Corn Residue Return (~65 lbs N/acre/year) Corn Nitrogen Cycling & 177 bushels Corn Nitrate Use (~165 lb N/acre) Gaseous Loss (~10 lbs N/acre/year) Fertilizer to Corn (~150 lbs N/acre/year) Native Soil Organic Matter Nitrogen ~ 10,000 lb N/acre Microbial production of nitrate from native soil ( lbs N /acre/year) Microbial re-uptake of nitrate ( lbs N/acre/year) NITRATE Nitrate leaching to water (~30 lbs N/acre/year)

25 Soybean Nitrogen Cycling & 51 bushels Soybean Grain Harvest (~165 lbs N/acre/year) Soybean Residue Return (~65 lbs N/acre/year) Soybean Nitrogen Use (~230 lb N/acre) Atmospheric Fixation (~100 lbs N/acre/year) Gaseous Loss (~2 lbs N/acre/year) Soybean Nitrate Use (~130 lb N/acre/year) Native Soil Organic Matter Nitrogen ~ 10,000 lb N/acre Microbial production of nitrate from native soil ( lbs N /acre/year) Microbial re-uptake of nitrate ( lbs N/acre/year) NITRATE Nitrate leaching to water (~30 lbs N/acre/year)

26 Soil Nitrate Production Rate Is High

27 Soil Nitrate Production vs. Crop Nitrate Uptake Rate of soil nitrate production from native soil organic matter Rate of corn or soybean nitrate uptake The majority of nitrate used by corn and soybean comes from soil nitrate production. Corn gets the difference from fertilizer while soybean gets the difference from legume fixation of atmospheric nitrogen. March February In the shaded areas, the soil produces nitrate, but there is no crop to use it. As a result, some nitrate is lost to waterways.

28 Soil Nitrate Production vs. Crop Nitrate Uptake Addition of a Cover Crop Rate of soil nitrate production from native soil organic matter Rate of corn or soybean nitrate uptake Cover crops can use nitrate when corn and beans are not growing, thus reducing the asynchrony between soil nitrate production and crop nitrate uptake. Cover crop nitrate use Cover crop nitrate use March February In the shaded areas, the soil produces nitrate, but there is no crop to use it. As a result, some nitrate is lost to waterways.

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30 Saturated Buffers Bioreactors Wetlands Shallow Drainage Drainage Management 2 yrs Alfalfa + 3 yrs Corn Rye Cover Crop vs. No Rye Poultry Manure vs. Fertilizer Swine Manure vs. Fertilizer Nitrogen Fertilizer Management 4Rs Soil test Sidedress vs. Pre-plant Spring Split vs. Fall N Fall vs. Spring N Sidedress vs. Pre-plant Nitrapyrin MRTN Adapted from Chris Hay, ISA % Nitrate Load Reduction

31 Saturated Buffers Bioreactors Wetlands Shallow Drainage Drainage Management In-Field/ Land Use Change 2 yrs Alfalfa + 3 yrs Corn Rye Cover Crop vs. No Rye Poultry Manure vs. Fertilizer Swine Manure vs. Fertilizer Nitrogen Fertilizer Management 4Rs Soil test Sidedress vs. Pre-plant Spring Split vs. Fall N Fall vs. Spring N Sidedress vs. Pre-plant Nitrapyrin MRTN Adapted from Chris Hay, ISA % Nitrate Load Reduction

32 Saturated Buffers Edge-of-Field (tiles only) Bioreactors Wetlands Shallow Drainage Drainage Management In-Field/ Land Use Change 2 yrs Alfalfa + 3 yrs Corn Rye Cover Crop vs. No Rye Poultry Manure vs. Fertilizer Swine Manure vs. Fertilizer Nitrogen Fertilizer Management 4Rs Soil test Sidedress vs. Pre-plant Spring Split vs. Fall N Fall vs. Spring N Sidedress vs. Pre-plant Nitrapyrin MRTN Adapted from Chris Hay, ISA % Nitrate Load Reduction

33 Saturated Buffers Edge-of-Field (tiles only) Bioreactors Wetlands Shallow Drainage Drainage Management In-Field/ Land Use Change 2 yrs Alfalfa + 3 yrs Corn Rye Cover Crop vs. No Rye Poultry Manure vs. Fertilizer Swine Manure vs. Fertilizer Nitrogen Fertilizer Management 4Rs Soil test Sidedress vs. Pre-plant Spring Split vs. Fall N Fall vs. Spring N Sidedress vs. Pre-plant Nitrapyrin MRTN Adapted from Chris Hay, ISA % Nitrate Load Reduction

34 Nitrogen fertilizer mismanagement is not the cause of nitrate loss. It s the lack of a rapidly growing crop during times when the soil is warm and wet. Drainage can improve soil health, and it s an opportunity reduce nitrate loss.

35 When we consider quantification of soil health, how might improved drainage affect the organic matter-based measurements?

36 Michael Castellano on twitter