Module 2: Your Living Soil

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Module 2 Your Living Soil

• Soils
• Soil Quality
• Fertilizing
• Soil Surveys
• Irrigation

NRCS
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Getting Down and Dirty With Soil

• Developed by
• Hudson Minshew, Oregon State University Extension
  Service
• Susan Donaldson, University of Nevada Cooperative
  Extension

USDA NRCS
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Lesson 1 Agenda

• Soil texture and structure
• The living soil
• Understanding soil erosion
• Reducing soil erosion
• Improving your soil
• Taking a soil sample

NRCS, Mont.
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What describes a good soil?

• Drains well
• Doesnt crust after planting
• Soaks up heavy rains with little runoff
• Stores moisture for drought periods
• Has few clods and no hardpan
• Resists erosion and nutrient loss
• Produces healthy, high quality crops

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How are soils formed?
A. Miller
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What are soils made of?

• Minerals
• Air
• Water
• Organic matter (humus)

www.statlab.iastate.edu
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Soil minerals
A. Miller
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The soil textural triangle
A. Miller
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Textural trianglefor the graphically challenged
NRCS, Bozeman Mont.
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Texture by feel Sand
Adapted from NRCS, Bozeman Mont. by A. Miller
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Why determine soil texture?

• Soil texture influences
• Water intake rates
• Water-storage capacity
• Ease of tillage
• Amount of aeration
• Soil fertility

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Soil texture affects drainage
In this experiment, an equal amount of water was
applied to three soil types.
NRCS, Bozeman, Mont.
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worm
USDA NRCS
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Benefits of soil organic matter

• Increased water- and nutrient-holding capacity
• Formation of soil into stable aggregates
• Reduced soil compaction
• Improved water infiltration

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What threatens my soil?
NRCS, Bozeman, Mont.
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Signs of water erosion

• Small rills and channels on the soil surface
• Soil deposited at the base of slopes
• Sediment in streams, lakes, and reservoirs
• Pedestals of soil supporting pebbles and plant
  materials

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Soil quality

• An assessment of the capacity of a soil to
• Sustain plant and animal productivity
• Maintain or enhance water and air quality
• Support human health and habitation

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Page 12
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How do I know what to add to my soil???
A. Miller
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Test your soil!
Use the slice method for a representative
sample.
UNCE, Reno, Nev.
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Managing Soil to Keep It Productive

• Developed by
• Hudson Minshew
• Oregon State University Extension Service
• Susan Donaldson
• University of Nevada Cooperative Extension

NRCS, Bozeman, Mont.
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Lesson 2, Part 1 Fertilizing

• What do my soil test results mean?
• What nutrients do plants need?
• How can I supply those nutrients?

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pH

• Indicates relative acidity or alkalinity
• pH 7 neutral less than pH 7 acid more than
  pH 7 alkaline or basic

Adapted from library.thinkquest.org by A. Miller
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Soil pH and nutrients
Adapted from www.soil.ncsu.edu by A. Miller
Widest part of the bar indicates maximum
availability
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Classifying salt-affected soils

• Electrical conductivity measurements (EC)
• Exchangeable sodium percentage (ESP)
• Salt-affected soils are commonly classified for
  management purposes into three groups saline,
  sodic, and saline-sodic based on EC and ESP

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Plant nutrients

• Substances necessary for plant growth
• Some, such as hydrogen, oxygen and carbon, come
  from the air and water
• Others, such as nitrogen and phosphorus, may need
  to be added
• Excess or improper use of fertilizers may result
  in water pollution

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Macronutrients

• N nitrogen
• P phosphorus
• K potassium
• H hydrogen
• O oxygen

• C carbon
• Ca calcium
• Mg magnesium
• S sulfur

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Micronutrients

• Fe iron
• Mn manganese
• Zn zinc
• B boron
• Mb molybdenum

• Ni nickel
• Cu copper
• Co cobalt
• Cl chlorine

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Whats in the bag?
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Calculating fertilizer rates
To convert a recommendation to pounds/acre of an
actual fertilizer material, use the following
formula
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Nutrient deficiencies
USDA NRCS
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Lesson 2, Part 2 Soil Surveys

• How to use a soil survey
• How to find a map unit
• Map unit descriptions
• Soil ratings and capabilities

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http//websoilsurvey.nrcs.usda.gov
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How do I use a soil survey?

• Locate your property on the Index to Map Sheets
  page
• Note the number of the map sheet
• Find that sheet
• Locate your property on the map sheet
• Make a list of map unit symbols

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Soil map unit example

• 630 Fleischmann gravelly clay loam

Name given by soil scientists conducting survey
Number designation
Soil textural class is part of map unit name
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Soil limitations
NRCS, Bozeman, Mont.
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Other information

• Suitability ratings
• Temperature and precipitation data
• Freeze dates and growing season
• Productivity
• Building site development

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Capability classes
USDA NRCS
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Got Water?
Developed by Hud Minshew, Oregon State
University Extension Service Susan Donaldson,
University of Nevada Cooperative Extension
UNCE, Reno, Nev.
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Lesson 3 Agenda

• Sources of irrigation water surface versus well
  water
• Matching available water to soils and plants
• Determining when its time to irrigate
• Irrigation systems

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Where will you get your water?

• Do you have a water right?
• Where will your water come from?
• When or how often will you get your water?

www.farmphoto.com
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Things to know before you start to irrigate

• What plants do you want to grow?
• Do you have enough available water to support the
  plants?
• Are your soils appropriate for growing the plants
  you selected?

UNCE, Reno, Nev.
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Where do plants get their water from in the root
zone?
Adapted from PNW 475 by A. Miller
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Soil texture and drainage
A. Miller
Soil texture Infiltration rate, inches per hour
Sand 2 - 4
Sandy loam 1 - 3
Silt loam, loams 0.25 1.5
Silty clay loams, clay 0.1 0.3
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Available water
OSU Extension Service
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Available water
A. Miller
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When is it time to irrigate?

• Rule of thumb when the amount of water-holding
  capacity is at 50 -- but thats hard to tell!
• If your plants are showing signs of stress,
  irrigation is overdue
• Look for wilting or grasses that dont spring
  back up when stepped on

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The Look-and-feel Method
USDA NRCS
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Look-and-feel method
Clay, clay loam or silty clay loam at 25 to 50
moisture
Clay, clay loam or silty clay loam at 50 to 75
moisture
Irrigation is overdue.
Will need to irrigate soon.
USDA NRCS
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Look-and-feel method
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Irrigation methods selecting the system thats
right for you
Surface
Sprinkle
USDA NRCS
Micro-irrigation
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Are you using an existing system, or starting
over?

• Your flexibility may be limited with an existing
  system, but costs will be lower
• Starting over allows you to carefully match
  soils, plants and water availability with
  irrigation systems, but can be costly
• New irrigation systems may save time, money or
  water

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What source of power will you use?

• None select an irrigation system that does not
  require power
• Electricity from an existing power line
• An internal combustion engine
• Solar power

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Surface irrigation (gravity-flow)
UNCE, Reno, Nev.
NRCS Irrigation Page
UNCE, Reno, Nev.
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Contour-furrow irrigation
Icrisat.org
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Powered systems sprinklers
UNCE, Reno, Nev.
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Low-energy precision-applicationsprinklers
USDA NRCS
USGS
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Drip irrigation
Graphic by A Miller, adapted from USDA-SCS 1984
USDA SCS
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Checking your systemDoes it apply water
uniformly?
UNCE, Reno, Nev.