Nick RamseyNatural Resources Conservation

ServiceDistrict Conservationist

610-372-4655 X110

OUR PERSPECTIVE ON OUR SOIL’S HEALTH

(Doran and Parkin, 1994)

Soil health is…“the capacity of the soil to function.”

for its intended use

Soil should…

…manage the flow of energy from the sun.…store and release

water.…cycle crop nutrients.

Soil should manage the flow of energy from the sun

Bare fields do not convert light energy into chemical

energy

Heat

Producers (plants and other photosynthetic organisms)

Chemical energy

Heat

Consumer

Consumer

Ray Archuleta

Plants: transformers of energy for the soil system

Root exudates are bacterial food.

Soil should store and release water

Soil Cover %

100%

0%30%

Rainfall Simulator

Soil Aggregate stability

In flight from Greensboro, NC to

Atlanta, GA. (April 22, 2007)

Not effective

Plant root

Runoff

Infi

ltratio

n

Runoff

Effective Physical disturbance disrupts the water cycle at the soil pore!

Glomalin (soil glue)- holds soil particles together:

• Increases infiltration

• Prevents sealing of the soil surface

Loss of SOM as CO2

CO2CO2CO2

PHYSICAL DISTURBANCE: Tillage induces native bacteria to consume soil carbon; byproduct is C02.

Tillage disrupts pore space and affects the water cycle

Soil should cycle crop nutrients

Nutrients from Fertilizer Nutrients from Soil C

NPK

Physical disturbance disrupts the Nutrient Cycle

Allow plants to feed microbes and microbes feed plants

Types of Soil Organisms

Bacteria Soil Fungi Soil Protozoa Nematodes Arthropods Earthworms

Bacteria

Bacterial Services Decomposition of OM Nutrient cycling Nitrogen fixation Nitrification Denitrification Disease Suppression Breakdown of hard to

decompose compounds

Fungi- Service they provide

•Decompose Organic Matter

•Glomalin secretion develops soil structure

•Extract nutrients•Hold nutrients

Protozoa

Nutrient mineralization

Regulation of bacterial populations

Food source themselves

Nematodes – Services they provide

A fungal-feeding nematode

• Control disease • Cycle nutrients•Disperse bacteria & fungi

A bacteria-feeding nematode

Arthropods

Earthworms

Earthworms Poor soils contain 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

Drilosphere: Zone of earthworm influence

•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)

The Soil Food Web

Typical Numbers of Soil Organisms in Healthy Ecosystems

Ag Land Prairie Forest

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)

Principles to Improve Soil Health

Less Disturbance

More Diversity

Living Roots

Keep Soil Covered

Soil Health Principle 1

Manage More by Disturbing Soil Less

Agricultural Disturbance Destroys Dynamic Soil Properties

Destroy “Habitat” for Soil Organisms

Creates a “Hostile” Environment Three Types of Disturbance

Physical (tillage) Chemical (Fertilizer) Biological (overgrazing)

Stop Tilling the Soil Tillage is physical 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

What things change when you stop tilling the soil?

Soil pores remain 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)

Human nature drives us to tillage!

•We enjoy power!•Feel in control!•We can see what we accomplished!

Hard to believe that the same results can be achieved using simpler biological methods!!!

Before Primary Tillage

After Primary Tillage

After Secondary Tillage

Dr. D.C. Reicosky, ARS, Morris, MN.

Less Disturbance

Also: Irrigation, Pesticides, Compaction, Fertilizer…

Overgrazing: disturbs soil and reduces root systems

30%

50%80%

60%

Soil Health Principle 2

Use Diversity of Plants to add diversityto Soil Organisms

Plants interact with 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

Impact of Biodiversity

Lack severely limits any cropping system

A diverse and fully functioning system provides nutrients, energy and water

Diversity above ground equals diversity below ground

How to Increasing Diversity in a Crop Rotation Lengthen the rotation 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

Cover Crop Role in Diversity

1. Allow you to 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”

Crop Classification Warm Season

Grasses

Corn Millet

Sudan Sudex Sorghu

m

Broadleaf Alfalfa Soybean Buckwheat

Chick pea Cow pea Sunflower

Crop Classification Cool Season

Grasses Barley Rye

Triticale

Wheat

Broadleaf

Canola Clovers

Mustards

Pea Radish Turnips

Mixture of cereal rye, hairy vetch, and field peas as a winter cover crop

Mixture of cereal rye, hairy vetch and crimson clover

Keep Living Roots in the soil as much as possible

Soil Health Principle 3

Grow Living Roots Throughout the Year

Benefits: Increases microbial activity 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

Root Mass in Top 4” of Soil

1-Ja

n

20-Ja

n

8-Fe

b

27-F

eb

17-M

ar

5-Apr

24-A

pr

13-M

ay1-

Jun

20-Ju

n9-

Jul

28-Ju

l

16-A

ug

4-Se

p

23-S

ep

12-O

ct

31-O

ct

19-N

ov

8-Dec

0

500

1000

1500

2000

2500

Rye & Hairy Vetch Cover Crop

Corn Grain

Soybean 7" rows

Lb

s./

ac.

A. H. Heggenstaller, University of Alberta

A. H. Heggenstaller, University of Alberta

How to Keep a Living Root All Year Long

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

Keep the Soil covered at all times.

Soil Health Principle 3

Keep it Covered as Much as Possible

Benefits: Control Erosion Protect Soil Aggregates Suppresses Weeds Conserves Moisture Cools the Soil Provides Habitat for Soil Organisms

Soil Temperatures

• Conserve moisture and reduce temperature.

• Crop yields are limited more often by hot and dry, not cool and wet.

When soil temperature reaches

140 F Soil bacteria die

130 F 100% moisture is lost throughevaporation and transpiration

113 FSome 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

Soil Organic Matter Nutrient Bank Account.

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.

Soil Organic Matter & Available Water Capacity

Percent SOM Sand Silt 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 Soil1 acre inch = 27,150 gallons of water

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

Other Economic Trade-offs of 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

Grazing

Management

is the Key to

Soil Health

on

Pastureland

Grazing Management Influences…

• Vegetative cover & distribution

• Species composition

• Soil organic matter

• Soil biology

• Deposition of nutrients

• Soil compaction

• Infiltration

Contributors to Soil Organic Matter on Pastureland

• Residues from non-consumed forage

• Plant roots

• Feces from grazing animals

• Soil organisms

• Application of organic materials

Plants: transformers of energy for the soil system

Root exudates are bacterial food.

Tall Fescue Tall Fescue Tall Fescue Orchardgrass Orchardgrass Fescue/BluegrassRotational Continuous Continuous Rotational Rotational Rotational

Continuously Grazed Tall Fescue Pasture, Bath County, Kentucky

Compaction as a Soil Health Concern on Pastureland

Compacted soil limits 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.

Compaction as a Soil Health Concern on Pastureland

Proper rest periods 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.

HOW CAN I TELL IF MY SOIL IS HEALTHY?

Simple Test to determine soil health

“Dig a Little, Learn a Lot”

In-field soil assessment what

to look at:

Look at: Residue Soil Surface Soil Profile Plant Roots ???

Utilize all your senses:• Sight• Smell• Touch• Taste????

How compressed is your soil?

From: Cornell Soil Health 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

June 16, 2009Corn planted into previous years’

cover crop residue

Brown’s

RanchSame Field

July 1, 2009Rapid residue decomposition

A Spade Deep, what it tells You

• Good Soil Tilth

• Sufficient depth

• Shredded Residue

• Signs of life

What About Color?

Darker color higher OM

Topsoil & Subsoil same color

• Not building OM• Mixing of soil

profiles• Poor soil health

Topsoil clearly defined

• No mixing• Deeper layer• OM is accumulating

Does your soil smell? 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

Do you have “Crumbly” Soil?

• Crumbles easily under finger pressure-GOOD

• Need a hammer to crush- BAD

What do Your Roots Say?

Healthy Roots• Uninhibited root 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)

Healthy Soil allows for Straight Roots

Compacted Layers

Roots run laterally on top of a compacted layer