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Organic Nitrogen Inputs and the Soil Food Web. 2 What is the Soil Food Web? Interaction and combination of all the organisms in the soil. Made up of an.

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Presentation on theme: "Organic Nitrogen Inputs and the Soil Food Web. 2 What is the Soil Food Web? Interaction and combination of all the organisms in the soil. Made up of an."— Presentation transcript:

1 Organic Nitrogen Inputs and the Soil Food Web

2 2 What is the Soil Food Web? Interaction and combination of all the organisms in the soil. Made up of an incredible diversity of organisms. They range in size from the tiniest one-celled bacteria, to small vertebrates, and plants. Fueled by Carbon, Nitrogen, minerals, water and Oxygen. Major components are the Nitrogen Cycle and the Carbon Cycle. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

3 3 The Soil Biology Primer (Chapter 2): By Elaine R. Ingham Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI Who eats Who

4 4 What do Food Web Organisms Do? Break down plant residues Release nutrients through microbial decomposition. Microbes add stabilized nutrients to both the Active and Stable fraction of the soil. Fix nitrogen from the atmosphere for the plants use. Fix Carbon and release CO2 Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

5 5 Why is a diversity of organisms important? Decomposition of Organic Matter requires diversity. In this interaction, one organism will break down an organic compound in the soil making the surplus by-products available as nutrients for other organisms. These organisms will in turn do the same thing and continue the cycle, eventually making the nutrients available to plants and animals. The microbial concentration and diversity impacts the speed and extent of nutrient cycling. The Soil Biology Primer (Chapter 2): By Elaine R. Ingham Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

6 6 The Food Web in Short Organic Matter Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

7 7 What are the requirements for an active Soil Food Web? Water Air Nitrogen (protein and other Nitrogen compounds) Carbon ( carbohydrates, i.e. - fuel) – Organic Matter Stable C:N ratio of below 15:1 - a higher number will cause a deficit of available Nitrogen. (Soil C:N is 12) The Soil Biology Primer (Chapter 2): By Elaine R. Ingham Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

8 8 Carbon is in the form of Organic Matter Organic matter is the vast array of carbon compounds in soil. Originally created by plants, microbes, and other organisms, these compounds play a variety of roles in nutrient, water and biological cycles. Organic matter can be divided into two major categories: Active fraction Stabilized organic matter The Active fraction is divided into living organisms fresh organic residue Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

9 9 Carbon Cycle Carbon is the Energy that Fuels the Microbes Stabilized Carbon (humus)

10 10 Components of Soil Organic Matter Soils with high organic matter content are the most productive, store more water and contribute to a better environment. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

11 11 Active Fraction Used by living plants, animals and microbes for food. Most of the Cycling of Nitrogen and Carbon Occurs here. The Active Fraction is the Short Term Bank where Nitrogen and Carbon are deposited and released quickly. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

12 12 Stabilized Organic Matter After years of decompostion, what remains are large, complex compounds that few microbes can degrade. (Humus) These hard-to-decompose, or stabilized, substances make up a third to a half of soil organic matter. The Stabilized Organic Matter is the Long Term Bank where Carbon and Nitrogen are in a very Stable Form and are released very slowly by microbial digestion. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

13 13 Increasing Microbial Activity Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

14 14 The Nitrogen Cycle Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

15 15 The Organic Nitrogen Fertilizer Input Cycle Organic Nitrogen Input is applied to the soil. Macro-organisms start the breakdown. (fungi, protozoa) The result of this macrobial action is amines and ammonia compounds. (plant food) A portion of the Nitrogen is bound into insoluble organic matter called Humus Humus is a ligno-protein residue of microbial tissue. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

16 16 The Nitrogen Fertilizer Input Cycle Bacteria (Microbes vs Macrobes) further break down amines & ammonia compounds into nitrites. (some loss to denitrification) Plants cannot use this form of nitrogen, so it is further broken down by bacteria into nitrates. Plants can then absorb this form of nitrogen but this is also the form that is lost to leaching. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

17 17 Understanding the Nitrogen Cycle Nitrogen Cycling is Dependant on Carbon Nitrogen Cycling is Dependant on Microbes Nitrogen Cycling feeds the Soil (microbes) which the Feed the Plant This occurs Primarily in the Active Fraction of the Soil The Important point is that BIOLOGY and ORGANIC MATTER is REQUIRED! Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

18 18 Examples: Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI Organic Nitrogen With No Biology

19 19 Examples: Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI Organic Nitrogen With Biology

20 20 Organic Fertility Goals Increase the Soil Food Web in order to increase the Activity of the Carbon and Nitrogen Cycles Increase the Active Fraction of Organic Matter (This where the N mineralized) Improve the Efficiency of Fertilizer Inputs Maintain a C:N Ratio of the Soil Below 15:1 so we dont create a Nitrogen sink. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

21 21 Differences in Input Characteristics Organic Nitrogen Inputs vary dramatically in how they Affect the Soil Food Web and Nutrient Cycling. They may be Differentiated by the C:N Ratio C:N Ratio determines how much of the N stays in the Active Fraction and how much goes to the Stable Fraction Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

22 22 Differences in Input Characteristics Organic Nitrogen Inputs may be Characterized by their Plant Available Nitrogen ( PAN) PAN is the amount of Nitrogen that will be Available to the Plant during the Growing Season In General: The higher the C:N ratio the lower the PAN Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

23 Organic Fertilizers 23Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

24 24 Plant Available Nitrogen (PAN) PAN is the quantity of Nitrogen Available during the growing season after a fertilizer is applied. The amount of Nitrogen Immobilized is dependant on the C:N Ratio. Higher the C:N Ratio the more N is Immobilized Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

25 25 How to Calculate PAN Variables: C: N Ratio of Organic Fertilizer Percent Nitrogen in Organic Fertilizer Total Pounds to be Applied Microbes have 8:1 C:N Ration Microbes use 25% Carbon for Growth, 75% for Energy Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

26 26 PAN Calculation Total N = (Pounds used) x (Percent Nitrogen) Total Carbon = (Total N) x (C:N Ratio) Carbon used for New Tissue = (Total C) x 25% (microbes use 25% of C for new tissue) Nitrogen Immobilized = (New tissue) / C:N Ratio of Microbes (8:1) PAN = (Total Nitrogen) – (Total Immobilized) In-Season Efficiency ( PAN) / (Total Nitrogen) Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

27 27 Examples (PAN) Turkey Litter 4% N, 12.5 C:N, 1000 lb/Acre Calculate for Total N: 1000 x 4% = 40 lbs Calculate for Total C: 40 x 12.5 = 500 Calculate 25% Lb New Tissue: 500 x 25% = 125 Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI Calculate N Immobilized, Using Microbe C:N of 8: 125 / 8 = Calculate PAN: = Calculate In-Season Efficiency: / 40 = 61%

28 28 Examples (PAN) Protein Fertilizer 8% N, 4.0 C:N, 1000 lb/Acre Calculate for Total N: 1000 x 4% = 80 lbs Calculate for Total C: 80 x 4 = 320 Calculate 25% Lb New Tissue: 320 x 25% = 80 Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI Calculate N Immobilized, Using Microbe C:N of 8: 80 / 8 = 10 Calculate PAN: = 70 Calculate In-Season Efficiency: 70/ 80 = 87.5%

29 Fertilizing Material PAN Efficiency Layer Poultry Litter69% Broiler Poultry Litter53% Feather Meal88% Seabird Guano94% Liquid Fish92% Corn Steep88% Molasses Deriv.81% Liquid Guano97% Organic Fertilizers PAN Efficiency 29Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

30 Fertilizing Material $/Ton 0r Gal. $/ lb N Layer Poultry Litter 4% N$250$4.55 Broiler Poultry Litter 4% N $250$5.88 Feather Meal 12% N$750$3.57 Meat & Bone 8% N$600$4.44 Seabird Guano 12% N$900$4.00 Liquid Fish 5% N$4.00$17.37 Liquid Guano 4.5% N$4.00$18.35 Organic Fertilizers Cost Analysis Including PAN 30Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

31 31Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

32 32 Other Issues Affecting SFW & Nutrient Cycling Excess use of Low PAN Inputs will increase the Soil C:N Ratio creating a Nitrogen deficit that will reduce the effectiveness of soil applied Nitrogen. This excess Carbon (raw organic matter) is unstabilized and serves as energy for microbes once Nitrogen is present resulting in Nitrogen going to the Stable Fraction. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI Excess Carbon

33 33 Other Issues………. What about the mineralization rate of various Inputs? Inputs have various rates of mineralization Mineralization rate is affected by the Input, Composition, Temperature, Soil Microbial Activity, etc. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

34 34 Crop Demand vs Mineralization What do we do when the Crop Demand for Nitrogen is less than the mineralization rate of the Fertilizer Input? Apply more fertilizer BUT How? What kind of fertilizer? When should it be applied? Can the cost be minimized? Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

35 35 Decision Making Information Mineralization Rate of Inputs PAN of Inputs Soil Nitrogen Levels of Nitrate, Ammonia and Total Nitrogen Total Nitrogen from all Sources (fertilizer, soil, compost, etc.) Crop Demand for Nitrogen Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

36 Organic Fertilizers 36Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

37 37 Nitrogen Input Decisions Liquid or Dry Fertilizer Dry Fertilizers have a 6 to 12 week Mineralization Rate depending on the Product Liquid Fertilizers have a 0 to 6 week Mineralization Rate depending on the Product In order to Synchronize Availability with Demand higher rates of Dry Inputs compared to Liquid Inputs will be needed due to the Mineralization Rate and PAN Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

38 38 Conclusions The Food Web is the micro-organisms that mineralize organic matter and produce humus for future use and soil stability. Soil is comprised of Living/Fresh & Active or Stable Organic Matter (Living/Fresh and Active is more available) PAN is higher for Low C:N ratio Inputs. High C:N contributes Nitrogen to the Stable Fraction (i.e.: not this crop) Feed the Soil to Improve the SFW Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

39 39 Further Conclusions PAN affects the true cost of a product. Solubility and Availability is important if you need a fast acting fertilizer. Use of very low C: N ratio Nitrogen fertilizers is better (feed the crop directly) for short season crops and Peak N demand periods Synchronizing applications with crop demand is critical for success. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

40 40 Organic Fertility Goals Increase the Soil Food Web in order to increase the Activity of the Carbon and Nitrogen Cycles Increase the Active Fraction of Organic Matter (This where the N mineralized) Improve the Efficiency of Fertilizer Inputs Maintain a C:N Ratio of the Soil Below 15:1 so we dont create a Nitrogen sink. Treat short duration deficiencies with low C:N Ratio Soluble liquids containing MINERALIZED Nitrogen to increase PAN. Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI

41 41 Thank You! This presentation will be available at Tim Stemwedel contact information: 7600 N. Ingram, Suite 121 Fresno, CA Organic Nitrogen Inputs and the Soil Food Web, Tim Stemwedel, COFI


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