What is soil health? What should you know about it?

Transcription

1 What is soil health? What should you know about it?

2 General Signs of Poor Soil Health Signs of runoff, erosion Structure destruction (POOR SOIL AGGREGATION) Compaction, Soil crusting, clods Rapid onset of stress during weather extremes High disease pressure Poor growth of plants Declining yields Increased needs for inputs

3 What do we want in a Soil: Good tilth and soil organic matter content Sufficient rooting depth Good conditions for water storage and drainage Enough (balanced) nutrients and free of toxic chem Diversity of beneficial micro-organisms Low soil born diseases and parasitic organisms Resistance to being degraded and eroded Resilience: quick recovery from adverse events

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5 Vulcan, Ab

6 Fort Kent, Ab

7 Acadia Valley, Ab

8 Consort, Ab

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10 Soil Processes OM OM OM H 2 O OM OM OM Soil minerals Clay Root uptake water & ions OM OM OM Aggregates H 2 O exchangeable Leaching to ground water H 2 O cycle

11 Precipitation Water Cycle evapo-transpiration Infiltration SW-storage Stream to deep ground water to stream

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13 Let s look at the soil main components How has soil been measured? ignored biological Biological Healthy Soil Physical Physical Chemical Chemical Little on physical Compaction Erosion Water Understanding infiltration soil biology and biological properties They are interdependent interactions within the soil ecosystem. When one of them is off balance, it will adversely impact on all three, thus reducing nature s potential contribution to profitable crop production.

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15 Physical Processes Resistance to soil Compaction Good tilth (aggregation-structure) - Aeration - Water storage & movement (infiltration) Resistance to soil erosion Physical support for plants House for soil food web - fungi, bacteria, arthropods, etc

16 Soil compaction effect on soil function: Decline in soil structural stability Poor aggregation Less porous Less air & water Decline in microbial activity Less aggregation stability Poor root growth poor water and nutrient uptake Decrease in water entering the soil (rain / snow) Reduce fertilizer efficiency.

17 Importance of Good Tilth-(Aggregate) Indicator: Aggregate stability Aggregate Promote Infiltration: ability to capture and storage moisture (rainfall and/or snow melting), water storage Less water runoff, compaction & erosion Porosity: more root exploration, drainage, Soil life Affected by soil management (ex. Crop Residue Removal)

18 Crop Residue Removal Biofuel feedstock Silage Mulch Bale Livestock feeding /bedding Other purposes

19 Assessing Corn Residue removal & Cover Crop on Soil Aggregate Stability South Dakota ( ) no-till soil management within a 2-yr corn/soybean rotation. Cover crop (slender wheatgrass and Lentil) Removal of corn residual at three levels (Low: only grain, Medium 50%, High: almost everything) The objective Results assess the impacts of corn (Zea mays L.) residue removal and cover crops on aggregation stability and other soil health properties cover crops as a tool to replace some of the organic matter lost through the residue removal process As the rate of residue removal increased, soil organic matter (SOM), wet aggregate stability (WAS), C/N, and microbial activity decreased significantly. Conclusion & recommendations Removal of corn residue had a negative impact in all soil properties measured, potentially illustrating the importance of crop residue to maintain our soil resource. Dr. Shannon Osborne (USDA)

20 Cover Crop on Soil Aggregation Slender wheatgrass on Soybeans broadcasted before full maturity Lentil on corn broadcasted tasseling stage Dr. Shannon Osborne (USDA)

21 Importance of Aggregate size Highly erodible fraction (<0.4 to 2 mm). very susceptible to wind and water erosion Large aggregate (6 to >19 mm) more stable & hold and capture moisture Dr. Shannon Osborne (USDA)

22 Corn residue removal impact on soil Aggregate size distribution 0-5 cm topsoil kg C ha kg C ha -1 10,469 kg C ha Measurement : High Residue Removal Large aggregate No cover crop 2012: Aggregate highly erodible fraction shift from 12 to 19 % Larger aggregate breaking down into more erodible class 32 to 29% With cover crop 2012: Maintain and increased the integrity of large aggregates 32 to 38 % 2000 Corn removal LRR, MRR & HRR 2005 Incorporate Cover Crop Dr. Shannon Osborne (USDA)

23 Importance of plant residue to Soil Health Protect and increase of larger aggregates reducing the erosive forces of wind and water Create a better habitat for microbial activity Contribute for aggregate stability.

24 Soils Biological Processes: *OM Residue Incorporation & Breakdown *Nutrient Cycling *Aggregation and Aggregate Stabilization

25 Soils Biological Processes: * OM Residue Incorporation and Breakdown Roots, crop residues, manures, composts Burying, shredding, ingestion, egestion Coating and inoculating Enzymatic degradation

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27 More Biological Processes Nutrient Cycling Transformation, Additions, Access Nitrogen Fixation, Ammonification, Nitrification, Denitrification Phosphorus Solubilization (P-solubilizing Rhizobacteria) Transport (Mycorrhizal fungi) Mineralization and Immobilization Release from OM, Storage and Retention C:N ratio

28 What does affect nutrient release? C:N ratio These nutrients are usable by plants, and they are mobile in soils Amoebas NH 4 + NO 3 - (Building Soils for Better Crops) C:N ratio of organic residues influences nutrients availability and rate of decomposition.

29 Biological Activities on N Cycle C:N ratio Brady and Weil, 2002

30 Soils, Plants and Microorganism Interactions Involve: Intricate system of communication Symbioses Bacteria & Fungus Nitrogen fixing leguminous plants Nitrogen fixing bacteria (Rhizobium) Plant provide nutrients to the bacteria Bacteria fix atmospheric nitrogen Bacteria (Rhizobium) Fungus (Mycorrhiza) Mycorrhiza symbiosis Arbuscular Mycorrhizal Fungi (AMF) Fungus teams up with plant roots Increasing absorbing root area up to 1000 times Exchange of sugar for P, water and other nutrients

31 What is the continue capacity of a soil to function as a living system? OM OM OM H 2 O OM OM OM Soil minerals Clay Root uptake water & ions OM OM OM Aggregates H 2 O exchangeable Leaching to ground water H 2 O cycle

32 Healthy soils are the product of diversity and microbial activities

33 Biological Interactions With Physical Properties Residue Incorporation and Breakdown Aggregation and aggregate Stabilization With Ecosystem Water purification, Toxin breakdown, C sequestration With Chemical Properties Nutrient Cycling and Storage CEC Organic Matter With Plant *Nutrient Access Plant Growth Promotion Plant Establishment Plant Disease Suppression

34 Aggregation Stability and Biological process

35 Important Biological Processes Aggregation and Aggregate Stabilization

36 Aggregates are stable to the action of water for several months and help prevent slaking and dispersion of the soil.

37 Important Biological Processes Residue Incorporation and Breakdown Nutrients cycling, access, storage Aggregation and Aggregate Stabilization

38 Chemical Processes Affected strongly by biol and phys processes H 2 O Root uptake water & ions Ion exchange Cation/Anion Exchange Capacity Nutrient storage & release Altered by ph Crops take up ions of: Macro-nutrients: N, P, S, K, Ca, Mg Micro-nutrients: Fe, Mn, Cu, Zn, Mo, B, etc Soil minerals Clay exchangeable Leaching to ground water

39 How management affect Soil health

40 Soil Degradation Spiral

41 All the Processes Together SOM H 2 O Root uptake water & ions Soil minerals SOM H 2 O H 2 O Clay SOM exchangeable Key that connect them all Leaching to ground water

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43 Cropping system Cocktail Effect of Crop Diversity 4 yr -T: Rotation: Corn/soybean/Sp-wheat/peas CC= Continuous Corn 5 yr Rotation: Corn/soybean/Sp-wheat/alfalfa T Continuous Corn NT Dr. Shannon Osborne (USDA)

44 Grazing System Management Slide by Dr. Dennis Hancock at the 2016 The Grassfed Exchange Conference: Storing Carbon & Building Soils Organic Matter through Grazing Management

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46 The Root of the problem is the root of the solution Rhizosphere (0.5-1 (around roots) Twice the numbers of microbes Highest biological activity Roots (exudates and roots) build SOM Greatest impact on soil aggregation (structure) Most of the Nutrient cycling activity Most impacted by above ground management

47 The latest on Soil Carbon Cycle on OM build up Roots (exudates and roots) build SOM Researchers support that they are the most important for building up SOM SOM below ground contribution to SOM above ground is ~1.5 to 3.7:1 ratio Roots: ~ 60-80% of soil organic matter Schmidt et al, Nature 478:49-56

48 Rhizosphere

49 Kochia root

50 How do we build a healthy Soil? We build a healthy soil first through biological activity not by physical or chemical manipulation Organic Matter Turnover Hatfield, 2004 Improved Nutrient Cycling Efficiency Yield Profit Improved Water Availability Improved Soil Structure Aggregation Stability Biological Activity

51 How do we build a healthy Soil? 1 st Create a microclimate for biology to express itself What biology wants? -Food, water, air & stable place to live Crop Residue / diversity CCC ---- Initial step to create a home Organic Matter Turnover Improved Nutrient Cycling Improved Water Availability Improved Soil Structure Aggregation Stability Efficiency Yield Profit Biological Activity

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54 Cover Crop Cocktail Case Study 1

55 Cover Crop Cocktail (CCC) & Chem Fallow effect on Physical process (Aggregation-Compaction) Field Observations Charles Schmidt farm-chinook, Ab CCC mix seeded Aug 11, 2014: Fababeans, Peas, Oats, Radish tillage, Barley, Millet

56 Cocktail Crop Seeding date: Aug 11, 2014 September October 8 September 18 October 20 November 21

57 Cocktail Crop -October 20 Cocktail Crop -October 20

58 Chem Fallow (Volunteer Canola) ~ 8 months after seeded

59 Cover Crop Cocktail ~ 8 months after seeded

60 ~8 months-comparation

61 Aggregate: ~9 months-chem Fallow Chem Fallow/Vcanola May 23, 2015

62 Aggregate: ~9 months-crop Cocktail

63 ~ 9 months

64 Compaction GPS- waypoints

65 Figure 2. Cocktail Cover Crop-Humalite effect on Soil depth Compaction at 300 PSI a a a Depth (inch) b c c c d d b b d _July Dry _July Moist _May Dry* _Aug Moist* 1 0 Control Ccrop Ccrop-GH Ccrop-LH Chem-GH Chem-LH Overall Area Cocktail Crop & Humalite Ccrop=cocktail cover crop, GH=granular humalite, LH=Liquid Humalite, Chem=Chem fallow Seeded Aug , frost terminated Nov 21, not statistical significant different *Statistical differences (3 months CCC). May 1- rooting depth up 8 inch (~2 inch-2014)

66 That soil was in the process of becoming a healthy soil Let s go back to the soil health definition the continue capacity of a soil to function as a living system A good soil health stage will be that where:

67 Cover Crop Cocktail Case Study 2

68 Andy s Grazing Cocktail Cover Crop Field history: 2016: 65 acres with a patch of hairy vetch Planted June 10 (all pic: Aug 27) Field was mowed before herd move in 2015: Grazing Corn & flax 2014: Durum 2013: Peas Seeding rate (20 $/a): lb/a Hazlet Fall Rye 30 Millet & sugar beet (each). 0,75 Collards, rapeseed & sunn Hemp (each) 1.5 Sunflowers did not performed well

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72 Highest Biological Activity

73 Highest Biological Activity

74 Different level of corn residue decomposition

75 Principe Island cocoa plantation Andy s field

76 Fungi diversity

77 Fungi diversity

78 Soil food Web: Arthropods (Shredders)

79 Soil characteristics Compacted Aggregated

80 Aggregated soil

81 Cody s Herd in (Sept 3)

82 Cody s Herd in (Sept 3)

83 Cody s Herd 38 cow/ calf pairs 6 yearling Heifers 2 Bulls Moving distance: 6 miles Comments: Cows concentrated first on the collards and left the hairy vetch till the end. The cows performed quite well, calves have grown a lot ( are big ), his young cows were in good condition. Sunflower stalk caused wounds on the bottom of their feet. 5% of the herd was affected.

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85 24 hours 3 inch water Infiltration Demo 30 kg/a of 2 years Cover Crop Cocktail site Bare Soil

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87 CCC 30 kg/a 1P CCC 80 kg/a 2P CCC 80 kg/a 1P CCC 60 kg/a 1P CCC 60 kg/a 2P Flax & Chickpeas Bare Soil Canola Wheat

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90 Bare soil

91 Cocktail soil Wheat soil

92 CARA s Soil Health Lab Initiative

93 CARA Soil Health (CARA-SHealth) Laboratory Initiative CARA s new adventure: To understand what is affecting the health of the soils in Alberta. The main goal: To allow producers to have access to biological and physical assessments to build the bridge for improving their soil health base on localized and side specific constraints.

94 What soil indicators should be measured? Soil health emphasizes the integration of biological chemical & physical measures Soil Aggregation Compaction Infiltration Structure Texture.. Physical Biological Chemical Respiration (CO 2 ) Active Carbon N mineralization C to N ratio Microbial activities Soil Food Web Fungi, bacteria, nematodes, etc.. Macro/micro nutrients ph, EC (salinity) CEC, OM.

95 Soil Food web: Active & Total Fungi, Active & Total Bacteria, Protozoa, Nematodes, Mycorrhizal colonization..

96 Thanks Any questions?