Importance and Management of Soil Organic Matter. Jodi DeJong-Hughes Extension Educator Soils and Crops ext 2006

Transcription

1 Importance and Management of Soil Organic Matter Jodi DeJong-Hughes Extension Educator Soils and Crops ext 2006

2 SOM in the United States Hargrove and Luxmoore

3 Components of Our Soil Biological Chemical Physical Image Etecllc.com

4 Biological Components Organic matter (OM) Microorganisms (MO s) Plant roots Large and small flora and fauna Abbey Wick, NDSU

5 Water Dynamics and OM 1% of OM can hold 27,000 gallons of water per acre Decreases evaporation USDA-NRCS Beman Hudson, photo- fanpop.com

6 65% of mo s live in top 12 of soil Bacteria Nematodes Actinomycetes Soil Biology Primer, NRCS, 1999 Fungi

7 In One Cup of Soil There Are Over 9 billion mo s 600 million bacteria (over 4,000 species) 5T of biomass/acre E. Ingham (

8 Functions Store and release nutrients Improve soil aggregation Biological and physical protection of diseases And much more Photo bmcdb.wordpress.com

9 What do Microorganisms Need to Grow and Thrive? Good Home: Food Water Temperature Protection Sometimes a host

10 Ia.state.edu Microbes and Manure

11 Microbe Plate Counts Trt MO Biomass Fungi Bacteria (ug/g) (cfu/g) (x1,000) Manured ,920 Non-manured ,670 Samples taken at the WCROC on July 18 th, 2002 on soybean fields. ARS analyzed soil samples

12 Photo Carinbondar.com Arbuscular Mycorrhizae (AM) Form a physical barrier around the root Bring in nutrients and water

13 Nutrient Uptake (micrograms/plant) Element No Mycorrhizae With Mycorrhizae Increase in Nutrients Phosphorus 750 1,340 44% Potassium 6,000 9,700 38% Calcium 1,200 1,600 25% Magnesium % Zinc % Iron % Jill Clapperton

14 Chemical Components ph Nutrient holding capacity (CEC) Nutrient availability Salts Abbey Wick, NDSU, photo globalhealingcenter.com

15 Nitrogen Cycle - Inputs N Fertilizer, NH 3, NO 3 - Legume N 2 Fixation Nitrogen Gas (N 2 ) Plant residue and manure

16 Nitrogen Cycle N Fertilizer, NH 3, NO 3 - Legume N 2 Fixation Nitrogen Gas (N 2 ) Plant residue and manure Mineralization Immobilization NH 4 + Nitrification NO 3 -

17 Nitrification (aerobic) a. Nitrosomonas NH O 2 NO H + + H 2 O Ammonium to Nitrite b. Nitrobacter NO O 2 NO - 3 Nitrite to Nitrate

18 Temperature and Leaching Potential Date Applied Soil Temp at 6 Converted to NO 3 in 2 weeks (lb/ac) Oct (~50%) Oct (~15%) Oct lb/a Urea applied Averaged over no-till, chisel and moldboard Schmitt, Illinois

19 Nitrogen Cycle - Outputs N Fertilizer, NH 3, NO 3 - Legume N 2 Fixation Nitrogen Gas (N 2 ) Plant residue and manure Crop removal NH 4 + NH 3 Volatilization Plant Uptake Mineralization Immobilization NH 4+ + NO 3 - NH 4 + Nitrification NO 3 - Denitrification NO 3 - N 2 + N 2 0 Leaching

20 Denitrification (anaerobic) 13 different bacteria: NO 3 - NO 2 -, NO, N 2 O, N 2 Nitrate to gaseous forms of N (nitrite, nitric oxide, nitrous oxide, N gas) Can lose up to 2-4 pounds/acre/day

21 What is the Nutrient Value of Soil Organic Matter?? Assumptions: 2,000,000 lbs. soil in top 6 in. 1% organic matter = 20,000 lbs.

22 Nutrients Nitrogen: 1,000 lbs x.63/lb $630 Phosphorus: 100 lbs x.60/lb $ 60 Potassium: 100 lbs x.42/lb $ 42 Sulfur: 100 lbs x.45/lb $ 45 Carbon: 10,000 lbs or 5 ton $ 0 Value of 1% SOM Nutrients/Acre ~$775

23 Physical Components Aggregation Porosity Bulk density Water movement, availability and storage

24 Many Benefits from Soil Structure

25 #1 Natural Defense Against Soil Compaction And Tillage Structure!

26 Air Permeability and CT Images of a Clay Affected by Compaction

27 Water Stable Aggregates 25 yrs of conventio nal corn 20 yrs of bluegrass, then 5 yrs conventional

28 Tillage DESTROYS Structure!

29 Wind Erosion Wind erosion occurs from wind speeds greater than 13 mph on smooth, wide, bare fields Photos: D. Gatchell

30 2011 NRI, Regents NRCS of the University of Minnesota. All rights reserved.

31 15% residue The Value of Snirt (snow + dirt) 45% residue

32 Low 1.6 T/ac Soil Accumulation in 6 WC - MN Ditches High 32.6 T/ac Average 9.1 T/ac

33 Nutrient $/lbs Ave Lbs of Nutrient Lost/Acre Ave Money Lost/Acre Nitrogen $ $27.50 Potassium $ $15.54 Phosphorus $ $ 7.80 Total $50.84/ac Loss not including the B, Fe, Mn, Mg, Cu, Ca, Co

34 Shelterbelts needed for high sustained winds

35 Acceptable soil loss is 5T an acre per year 40 acres = 16 dump truck loads of soil!

36 Value of Topsoil 5T/ac x $25/T x 40 ac = $5,000

37 Cover - the single most important factor influencing soil loss!!

38 Differences in Equipment fxtimes.com

39 Vertical Till Classified as mulch till. Shallow (1-3 ) and full field tillage.

40 Benefits of Vertical Tillage: Can get into wet fields

41 Chops and Sizes Residue

42 Leaves Some Residue Intact

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44 Primary and Secondary Tillage

45 Speed - 7 to 10 mph

46 Limited Fertilizer Incorporation

47 Where to Try Vertical Tillage Sizing residue and introducing air Wet Spring or Fall When fall tillage wasn t completed

48 Where to Try Vertical Tillage Decrease residue build-up Leaves residue = good on slopes Rotational tillage

49 Field Cultivator

50 3-4 Depth Even mixing of soil

51 Even fertilizer and weed incorporation

52 Challenges: Little residue remaining VT ST FC

53 Smearing in a Wet Soil

54 Field Cultivator Mgmt One pass in spring Shallow incorporation of nutrients Use least aggressive set-up Versus

55 Disks

56 Disks More destructive forces Shears and presses soil

57 Great at Sizing Residue and Clods Too good deere.com

58 Challenges for a Disk Loss of soil structure and moisture More compaction potential Major residue incorporation Keep it shallow

59 Where to Use a Disk To break up clods and make a roadbed

60 Equipment Differences Chisel and Shanks: Lifts and separates the soil Less destruction of soil structure

61 Even CP Can Be a Conservation Tool It s all Relative Residue burial variable depending on point Less fuel and time compared to MBP and DR Incorporate manure and fertilizer Provided by Dick Wolkowski, UW

62 Chisel Plow Points Provided by Dick Wolkowski, UW

63 Twisted Shovel vs. Sweep Provided by Dick Wolkowski, UW)

64 Variable Depth Tillage!! VT and/or Chisel Plow

65 Strip Tillage

66 Maintains surface residue between the rows Considered enhanced no-till

67 Seed planted directly in cleared strips in Spring P and K applied 6-8 deep in berm N can be applied in berm, at planting or side dressed

68 3 Year Tillage Research Fall of 2009 Carlisle and Clarkfield, MN Looking at varying residue levels

69 Soybean Data - Clarkfield Vertical Till, 2 passes Vertical Till, 2 passes (prev. tillage, CP) (prev. tillage, DR)

70 Corn Data - Clarkfield Vertical Till, 2 passes (prev. tillage, VT) (prev. tillage, CP)

71 Sun No-Till Vertical Tillage Chisel Plow Strip Tillage crop residue top soil subsoil

72 Sun 42 o F 47 o F 50 o F 51 o F 45 o F No-Till Vertical Tillage Chisel Plow Strip Tillage

73 Saturated Soil Sun 50% Water Water 32% 25% 19% 18% 29% No-Till Vertical Tillage Chisel Plow Strip Tillage

74 Natural Tillage in Dry years

75 Think about tillage based on: Residue levels Slope Soil type/texture Drainage ability

76 Tips to Reduce Tillage Evenly spread chaff Shallow-up tillage depth Try to cut out a tillage pass Change-out twisted points, use narrow points Planter in great working order

77 Reduced Tillage Saves: Time, labor, fuel Organic matter Structure Your SOIL!

78 Questions?