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Healthy soils
This document discusses principles of soil health and how soil functions. It explains that soil should manage energy flow from the sun, store and release water, and cycle nutrients. Soil health relies on a diverse community of organisms and having living roots in the ground as much as possible. Agricultural practices like tillage and overgrazing can disrupt these functions by destroying soil habitat and organisms. The document recommends managing for less soil disturbance, more plant diversity, keeping living roots, and keeping the soil covered to improve soil health.
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Healthy soils
- 1. Nick Ramsey Natural ResourcesConservation Service District Conservationist 610-372-4655 X110
- 2. (Doran and Parkin,1994) Soil health is… “the capacity of the soil to function.” for its intended use
- 3. Soil should… …manage theflow of energy from the sun. …store and release water. …cycle crop nutrients.
- 4. Soil should managethe flow of energy from the sun
- 5. Bare fields donot convert light energy into chemical energy Heat Producers (plants and other photosynthetic organisms) Chemical energy Heat Consumer Consumer Ray
- 6. Plants: transformers ofenergy for the soil system Root exudates are bacterial food.
- 7. Soil should storeand release water
- 8. Soil Cover % 100%0%30% Rainfall Simulator
- 10. In flight fromGreensboro, NC to Atlanta, GA. (April 22, 2007)
- 11. Not effective Plant root Runoff Infiltration Runoff Effective Glomalin(soil glue)- holds soil particles together: • Increases infiltration • Prevents sealing of the soil surface
- 12. Loss of SOMas CO2 CO2 CO2CO2 PHYSICAL DISTURBANCE: Tillage induces native bacteria to consume soil carbon; byproduct is C02. Tillage disrupts pore space and affects the water cycle
- 13. Soil should cyclecrop nutrients
- 14. Nutrients from FertilizerNutrients from Soil C NPK Physical disturbance disrupts the Nutrient Cycle Allow plants to feed microbes and microbes feed plants
- 15. Bacteria SoilFungi Soil Protozoa Nematodes Arthropods Earthworms
- 16. Bacterial Services Decompositionof OM Nutrient cycling Nitrogen fixation Nitrification Denitrification Disease Suppression Breakdown of hard to decompose compounds
- 17. Fungi- Service theyprovide •Decompose Organic Matter •Glomalin secretion develops soil structure •Extract nutrients •Hold nutrients
- 18. Nutrient mineralization Regulationof bacterial populations Food source themselves
- 19. A fungal-feeding nematode • Controldisease • Cycle nutrients •Disperse bacteria & fungi A bacteria-feeding nematode
- 22. Poor soilscontain 250,000 earthworms per acre while good soils contain 1,750,000 per acre 1 or less per shovel indicates poor soil health 10 or more per shovel indicates good soil health Burrowing through lubricated tunnels forces air in and out of soil Earthworm casts contain 11% of the humus 7X the nitrogen 11X the phosphorus 9X the potash than surrounding soil
- 23. •Redistributes plant litter “Carbon”throughout the soil the profile • Soils are enriched with N,P, and humified organic matter •Increase water infiltration •Provide a bio pore for plant roots •Homogenize soil surface •Increase bio-diversity in soils M.H. Beare, D.C. Coleman, D.A. Crossley Jr., P.F. Hendrix and E.P. Odum (1995)
- 25. Ag Land PrairieForest Organisms per gram (teaspoon) of soil Bacteria 100 mil. - 1 bil. 100 mil. - 1 bil. 100 mil. - 1 bil. Fungi Several yards 10s – 100’s of yds 1-40 miles (in conifers) Protozoa 1000’s 1000’s 100,000’s Nematodes 10-20 10’s – 100’s 100’s Organisms per square foot Arthropods < 100 500-2000 10,000-25,000 Earthworms 5-30 10-50 10-50 (0 in conifers)
- 26. Principles to ImproveSoil Health Less Disturbance More Diversity Living Roots Keep Soil Covered
- 27. Agricultural DisturbanceDestroys Dynamic Soil Properties Destroy “Habitat” for Soil Organisms Creates a “Hostile” Environment Three Types of Disturbance Physical (tillage) Chemical (Fertilizer) Biological (overgrazing)
- 28. Tillage isphysical soil disturbance Destroys aggregates Exposes organic matter to decomposition Causes compaction Damages soil fungi Reduces habitat for all members of SFW Disrupts soil pore continuity Increases salinity at the soil surface
- 29. Soil poresremain continuous Soil aggregates form and are not destroyed Soil Food Web increases and diversifies Weed seeds are not planted Water is captured and stored Bulk density increases slightly; then stabilizes Soil fungi and earthworms increase Microarthropods increase (>20% of nutrient cycle)
- 30. •We enjoy power! •Feelin control! •We can see what we accomplished!
- 31. Hard to believethat the same results can be achieved using simpler biological methods!!!
- 32. Before Primary Tillage After Primary Tillage After Secondary Tillage Dr. D.C. Reicosky,ARS, Morris, MN. Less Disturbance Also: Irrigation, Pesticides, Compaction, Fertilizer…
- 33. Overgrazing: disturbs soiland reduces root systems 30% 50% 80% 60%
- 34. Plants interactwith particular microbes Trade sugar from roots for nutrients Microbes convert plant material to OM Requires a diversity of plant carbohydrates to support the variety of microbes Lack of plant diversity will drive system to favor some microbes more than others
- 35. Lack severelylimits any cropping system A diverse and fully functioning system provides nutrients, energy and water Diversity above ground equals diversity below ground
- 36. Lengthen therotation by adding more crops Increases soil organic matter Breaks pest cycles Improves nutrient utilization and availability Utilize available water deeper in the soil profile Provide windows for management spread manure Plant & harvest crops Add more plants in the current crop rotation Utilize cover crops during non-cropping part of the year
- 37. 1. Allow youto look at cropping periods rather than years 2. Can be used to accelerate rejuvenating soil health 3. Getting 6 to 8 weeks of growth is adequate to get some of the “rotation” effect benefits! 4. Will increase soil biological diversity “Diversity above = diversity below”
- 38. Grasses Corn Millet Sudan Sudex Sorghum Broadleaf Alfalfa Soybean Buckwhea t Chick pea Cow pea Sunflower
- 39. Grasses Barley Rye Triticale Wheat Broadleaf Canola Clovers Mustard s Pea Radish Turnips
- 40. Mixture of cereal rye,hairy vetch, and field peas as a winter cover crop Mixture of cereal rye, hairy vetch and crimson clover
- 41. Keep Living Rootsin the soil as much as possible
- 42. Benefits: Increases microbialactivity influences the N mineralization and immobilization Increases plant nutrient/vitamin uptake/ concentrations with mychorrhizal and bacteria associations Increases biodiversity and biomass of soil organisms Improves physical, chemical and biological properties of soils Sequesters and redeposit nutrients Increases OM
- 43. 0 500 1000 1500 2000 2500 Lbs./ac. Rye & Hairy VetchCover Crop Corn Grain Soybean 7" rows
- 44. A. H. Heggenstaller,University of Alberta
- 45. A. H. Heggenstaller,University of Alberta
- 46. Lengthen Rotation Add Wheat Select Shorter Season Varieties Choose 100 -104 day Only need 6 - 8 weeks to provide benefit Interseed into Growing Crops Planting cover crop before harvesting of cash crop
- 48. Benefits: Control Erosion Protect Soil Aggregates Suppresses Weeds Conserves Moisture Cools the Soil Provides Habitat for Soil Organisms
- 49. • Conserve moistureand reduce temperature. • Crop yields are limited more often by hot and dry, not cool and wet.
- 50. 140 F Soilbacteria die 130 F 100% moisture is lost through evaporation and transpiration 113 F Some bacteria species start dying 100 F 15% moisture is used for growth 85% moisture lost through 95 F evaporation and transpiration 70 F 100% moisture is used for growth J.J. McEntire, WUC, USDA SCS, Kernville TX, 3-58 4-R-12198. 1956
- 51. 1.0% OM= 20,000 # 10,000 # Carbon (5 ton) @ $4/ton = $20 1,000 # Nitrogen @ $.50/# = $500 100 # Phosphorous @ $.70/# = $70 100# Potassium @ $.40/# -=$40 100 lbs of Sulfur @ $.50/# = $ 50 Total $680 Mineralization Rate = 2-3% from Organic N to Inorganic N. Resulting in 20 to 30 lbs of useable N per acre.
- 52. Percent SOM SandSilt Loam Silty Clay Loam 1 1.0 1.9 1.4 2 1.4 2.4 1.8 3 1.7 2.9 2.2 4 2.1 3.5 2.6 5 2.5 4.0 3.0 Berman Hudson Journal Soil and Water Conservation 49(2) 189 194 189- March April 1994 – Summarized by: Dr. Mark Liebig, ARS, Mandan, ND Hal Weiser, Soil Scientist, NRCS, Bismarck, ND Inches of Water/One Foot of Soil 1 acre inch = 27,150 gallons of water
- 53. Harvesting crop residue– What’s it worth? Plant residue left on a field after harvest is a valuable resource. Non-market economics need to be considered when deciding to harvest residue. Corn Residue in Nebraska: • Average cost of harvesting crop residue: $60-$70/ac. • Value of removed nutrients: ~$26/ton (1 ton corn residue has 17 lbs. N, 4 lbs., P, 50 lbs K2O, and 3 lbs. S) • Yield reduction of 6% over 5-yr. continuous no-till corn with 50% residue removed each year. Nutrients removed can be replaced but the function of SOM can not. NRCS, NE Fact Sheet Sept. 2008
- 54. Other Economic Trade-offsof Residue Harvest • Potential long-term yield loss • More field passes, fertilizer & fuel use • Cost of practices to replace residue • Opportunity Costs: – C trading – Conservation Programs – Other uses
- 55. Grazing Management is the Keyto Soil Health on Pastureland
- 56. Grazing Management Influences… •Vegetative cover & distribution • Species composition • Soil organic matter • Soil biology • Deposition of nutrients • Soil compaction • Infiltration
- 57. Contributors to SoilOrganic Matter on Pastureland • Residues from non-consumed forage • Plant roots • Feces from grazing animals • Soil organisms • Application of organic materials
- 58. Plants: transformers ofenergy for the soil system Root exudates are bacterial food.
- 59. Tall Fescue TallFescue Tall Fescue Orchardgrass Orchardgrass Fescue/Bluegrass Rotational Continuous Continuous Rotational Rotational Rotational Continuously Grazed Tall Fescue Pasture, Bath County, Kentucky
- 60. Compacted soillimits root growth, seed germination, and infiltration. Bare soil is compacted (crusted) by rainfall. Compaction from hoof action is greatest on overgrazed pastures. Compaction may be significant when animals graze or equipment is operated on wet or saturated soils.
- 61. Proper restperiods in a managed grazing system will facilitate amelioration of compacted soil by plant roots, animals, and soil organisms. Arrange pasture layout and the location and design of watering and supplemental feeding facilities to minimize the area of concentrated use.
- 63. Simple Test to determinesoil health “Dig a Little, Learn a Lot”
- 64. Look at: Residue Soil Surface Soil Profile Plant Roots ??? Utilize all your senses: •Sight •Smell •Touch •Taste????
- 65. From: Cornell SoilHealth Manual Penetrometer - Measures pressure to penetrate soil Used to identify: •Surface crust •Tightly packed crumbs •Subsoil compacted layers Effects of compaction •Poor germination •Reduced infiltration •Poor root development •Poor air exchange
- 66. Brown’s Ranch Same Field July 1,2009 Rapid residue decomposition
- 67. • Good Soil Tilth •Sufficient depth • Shredded Residue • Signs of life
- 68. Darker color higherOM Topsoil & Subsoil same color • Not building OM • Mixing of soil profiles • Poor soil health Topsoil clearly defined • No mixing • Deeper layer • OM is accumulating
- 69. Earthy/Sweet Smell Geosmin from Actinomycetes Bacteria Decompose residue Cycle nutrients Important part of soil foodweb Metallic/Kitchen sink cleanser Soil dominated by Anaerobic bacteria Indicate anaerobic conditions Hydrogen Sulfide H2S rotten egg smell, NH3 Ammonia strong urine smell Drives pH low, release AL No soil aroma Little active life in the soil because it is too hot, cold, wet, dry or degraded to have many active soil organisms present at that time. Poor Habitat
- 70. • Crumbles easily underfinger pressure-GOOD • Need a hammer to crush- BAD
- 71. Healthy Roots • Uninhibitedroot growth • Lots of fine roots •White (no root pathogens) Unhealthy Roots • Restricted root growth • Few fine roots •Short thick roots • Discolored & Lesions (root pathogens present)
- 73. Roots run laterally on topof a compacted layer
Editor's Notes
- #24 Drilosphere: Zone of influence by earthworms and other microarthropods & millipedesFunction to shred and redistribute plant litter from the Detrituspherethroughout the soil profile, horizontally and vertically
- #28 Dynamic soil proprieties are those that can be influenced by human activitiesInclude: Soil Organic Matter Structure Infiltration rate nutrient and water holding capacity & availabilitySoil is Habitat that provides Food, Water & Shelter for organisms to liveAgricultural disturbance destroys habitat in which beneficial organisms could thrive and creates habitat that non-beneficial organisms can tolerate or thrive inAll three types of disturbance end in degraded soils
- #30 Here are 8 positive changes in the soil that occur when you stop tillage.Pores remain continuous-allows for increased infiltrationAggregates form – increase soil stability, improves aeration and provides habitat for soil microbesSFW – adds trophic levels and complexity, increasing functional groupsWater is held in place by increased SOM and held until plants require itBulk density decrease over time to levels that approach native condtionsSoil organisms flourish because there habitat is not being destroyed
- #31 Human’s relate hard physical work with success,
- #32 The challenge to soil health is to convince farmers that they can achieve many of the same results they are seeking when they till by using biological methodsPhotos are of tillage radish planted in a timely fashion that allows it to growing into the soil profile greater than 12”, notice the soil lineThe photo in the bottom right shows tillage radishes planted using a split row planter ever 4”. You can see the “bio-drilling that is being achieved, compares to the results that you can get with an inline ripper without the added cost of diesel fuelIn addition the tillage radish scavenge excess N, pull up P from deep in the soil profile and provide some nematode control as an added bonus
- #35 Plants exudates attract a particular variety of soil microbesMicrobes use these exudates to do the various function that support plant growth, e.g. decompose organic matter, cycle nutrients, enhance soil structure, and control populations of soil organisms including pestThe more plant exudates in the soil the wider variety of soil organisms that the soil can support, adds complexity and resilienceLack of diversity reduces the number and types of organism that can thrive, soils are less complex and lack resilienceReference the movie “Supersize Me” The movie is about a man that ate McDonalds food every meal for a month, the lack of diversity in his diet cause his blood work to get out of balance, he gained weight and his general health went down. His doctor’s pleaded with him to get off the diet. This is the same principle as feeding the soil corn exudates every year and the effect it has on the soil organisms
- #36 What impact does increasing biodiversity have on a cropping system?Lack of biodiversity limits the copping system, How?? Disrupts how soils function, less nutrient cycling, water infiltration, increase pest (weeds & diseases), etc.A diverse and fully functioning soil ecosystem means that: all the organisms that plants require are present and functioningNutrients in the soil are in the proper form for plants to take upNutrients are being held in the soil in non-leachable formsCorrect ratio of soil organisms are presentFungi to bacteriaPredator to preyWhen this occurs the system provides the energy, nutrients and water to produce cropsDiversity in plant community above ground equals or indicates a diverse soil biota
- #37 There are 2 basic ways to add plant diversity to a crop rotationLengthen the current rotation by adding more corps, e.g. corn-bean rotation goes to corn-beans-wheatBenefits include:Increase the amount of biomass produced can increase SOMPlanting difference crops breaks pest and weed cyclesPlanting a variety of shallow and deep rooted crops utilizes soil moisture and nutrientsProvides windows of opportunity to spread manure in more suitable time of the year, plant and harvest crops with out conflict, etc.Add more plants in the current rotationUtilize the non-cropping portion of the year to grow cover cropsBe sure to use multi-species cover crops when possible
- #38 Cover crops and multi-specie cover crops play a big role in adding diversity into a cropping systemFarmers are hesitant to add more cash crops to a rotation, cover crops allow for diversity to be inserted into periods of the year that normally would not have a living root growing and no exudates being placed into the soilSuccess of cover crops has always been judge by the amount of biomass produced above ground, we need to consider the amount of plant exudates that are feeding soil microbes for a period time that normally would not have gotten any food. Having roots grow for a short period of time accomplishes Multi-species cover crops will added to the biological diversity within the soil
- #41 Examples of multi-species cover crops
- #44 Graph is built on data from RUSLE2 run for Greensboro, NCIt shows the amount of root mass produced in the top 4” for corn, soybeans and a rye & hairy vetch cover cropTypical corn or soybean will only grow a living root for 100 to 110 days, leaving the soil with no living root growing for the majority of the yearAdding a multi-species cover crop growing in the non-cropping part of the year added over 2000 lbs. of root mass providing a food source year round
- #45 A. H. Heggenstaller, University of AlbertaTraditional cropping systems only have a living root growing 90 to 120 days of the yearNiches exist at both ends of the growing season that provide opportunity for cover crops to used to provide a living root
- #46 H. Heggenstaller, University of AlbertaCover crops can provide exudates to stimulate soil biology at both ends of the cropping season
- #47 There are a variety of ways to get cover crops seeded in order to take advantage of a longer growing seasonLengthen rotation, e.g. adding wheat in a C-B rotation Select shorter season varieties, need to have breeders look at higher yielding shorter season varietiesRemember having a living root growing for 6 to 8 weeks before a killing frost does provide benefitFigure out ways to interseed cover crops into growing crops
- #49 The benefits of keeping the soil covered have focused primarily on the erosion control side, we don’t need to discuss this much, thousands of HEL conservation plans have been written based on this.NRCS has totally missed the mark as providing residue all year round does more than prevent erosionCooler soils reduce evaporation and conserve moistureResidue provides habitat for soil organisms
- #50 Notice the temperature difference between bare soil and soil with cover crops.Thermometers are placed 40 feet apart in two differently managed fieldsSoil temperatures are 20 degrees cooler where cover crop is shading the soil
- #52 This is self explanatory, it shows the potential nutrients available in the SOM that can be tapped as soil health is improved and microbe activities is excellerated
- #53 This is AVAILABLE water not simply water being held in the soil profileWhat does it mean on a practical side The average increase in available water is .5” This amounts to an extra 13,575 gallons of available waterCorn water use at it maximum growth rate in the summer uses .25” to .3” of water or 6,000 to 8,000 gallonsThis amount of extra water would be equivalent to 2 irrigation events to meet corn needsThis would amount to decreasing the number of irrigation events needed orextending the time between eventsIt would also mean extra days between rainfall events before non-irrigated crops begin to stress
- #64 Using a spade or shovel to examine the soil is the best soil health evaluation tool available
- #65 This section we are trying to get the participants to learn how to evaluate existing soil health conditions using our sense and general knowledge about soil health
- #66 Measuring compaction in the field can be done using:Penetrometer: measure pressure to penetrate soil on a given day, subject to current soil moisture levels, will vary from day to dayCould use a survey flag or other type of rod to get a feel for were compacted layer occur, won’t give pressure reading but good place to start discussionsShovel is another good tool, how hard is it to get into the ground, will stop at compacted layers,
- #67 Photo are from Gab Brown’s farm in ND and demonstrate how quickly residue can breakdown when soils are healthy
- #68 Looking at a spade full of soil should begin to show evidence of soil healthHow hard was it to put the spade in the groundWere you able to get to a sufficient depth, 5” to 7”Is there sign of life, e.g. worms, millipedes, etc.Is the residue shreddedThese are all indicators of what’s happened in the past to impact soil health
- #69 Color is an indicator of soil organic matter,Should be concentrated in the surface with a clear defined, no line means mixing has been done (unless your dealing with a Molisol)
- #70 Photo is of Ray Covino, District Conservationist in Danielson, CT smelling health soil in ND.Slide is self explanatory
- #71 Using touch or feel can tell how health soils are, good soil aggregates should crumble easily under finger pressure, poor aggregates need more pressure to crush.Good aggregates are a result of following the 4 soil health principles
- #72 Roots are a great indicator of soil conditions, especially related to compaction.Roots should grow uninhibited into the soil profile, generally they hit a compacted layer at varying depths.Compacted layers that exceed 300 psi will restrict root growthRoots need a pore space greater than 0.1 mm