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.

Part One: Fertilizing  What do my soil test results mean?  What nutrients do plants need?  How can I supply those nutrients?

What kind of information does my soil test report provide?  Particle size analysis  Soil organic matter content  pH  Soluble salts  Nutrient content USDA NRCS

Particle size analysis  Provides the relative percentages of sand, silt, and clay  Allows determination of soil textural class  A loamy texture is generally best for most plants NRCS, Bozeman, Mont.

Soil organic matter (OM)  Living or dead plant and animal residue  Measured in %  OM content is highly variable  Generally, 3 to 8 % OM content is good for plants UNCE, Reno, Nev.

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

Soil pH and nutrients Adapted from by A. Miller Widest part of the bar indicates maximum availability

What makes soils acid?  Acid soils: pH is below 7  Soils become acid due to heavy rainfall that weathers soils quickly  Basic cations such as calcium, magnesium, and potassium are leached from the soil profile  This natural weathering process makes soils acid

Raising the pH of acid soils  Add lime to raise the pH (making soil less acid)  Lime most often consists of calcium carbonate  Plant response will be relatively slow, taking weeks or months

What makes soils alkaline?  Alkaline soils: pH is above 7  Soils that have not been greatly weathered or leached  Soils high in calcium  Reduces solubility of all micronutrients Adapted from library.thinkquest.org by A. Miller

Example of crop grown in alkaline soil

Adapted from ag.arizona.edu by A. Miller

Soluble salts  A measure of inorganic chemicals that are more soluble than gypsum, such as sodium, calcium, magnesium, chloride, sulfate and bicarbonate  Salty soils are a problem in arid regions or in poorly drained soils USDA NRCS

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

Managing salt-affected soils  Select plants that can tolerate salinity  Avoid excess or salty forms of fertilizers  Incorporate organic matter  If appropriate, add sulfur to lower the pH

Managing salt-affected soils  In soils with good drainage, periodically leach the salts below root zone with high quality irrigation water (avoid if high water table present)  Check with your local Extension office for help

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

Macronutrients N = nitrogen P = phosphorus K = potassium

More macronutrients H = hydrogen O = oxygen C = carbon Ca = calcium Mg = magnesium S = sulfur

Micronutrients Fe = iron Mn = manganese Zn = zinc B = boron Mb = molybdenum Ni = nickel Cu = copper Co = cobalt Cl = chlorine

Six questions to ask yourself before you add fertilizer 1.Which elements do I need? (N, P, K, S, Ca) 2.How much do I apply? 3.What type of material do I use? 4.Which application method is best? 5.When is the best time to apply it? 6.Will I get a return on my investment?

Types of fertilizers  Chemical fertilizers  Organic fertilizers (bone meal, compost, manure, etc.)

What’s in the bag? WAY TO GROW FERTILIZER 28 – GUARANTEED ANALYSIS Total nitrogen 28% 6% Ammonium nitrogen 14% Urea nitrogen Available phosphoric acid 14% Soluble potash 5% Derived from sulfur-coated urea, etc. Product name NPK formula Nitrogen content Phosphorus content Potassium content Specific sources

How much fertilizer do I need to apply?  Estimate the amount of fertilizer needed based on soil test results, crop needs and area to receive fertilizer  Most fertilizer recommendations are in pounds per 1,000 square feet, or pounds per acre

Calculating fertilizer rates X 100 Pounds of nutrient recommended Percentage of nutrient in fertilizer material To convert a recommendation to pounds/acre of an actual fertilizer material, use the following formula :

Calculating land area  Length x Width = Area  If the area is oddly shaped or oval, calculate using a regular shape that closely fits the shape of the land to be fertilized 100 ft 200 ft 150 ft

Fertilizing with manures  Good source of nutrients and organic matter  Protects soil from raindrop impact and erosion  Local supply often available at no cost OSU Extension Service

 Poultry manure is high in nitrogen  Beef and horse manure tends to be lower in nitrogen  Sheep manure is high in potassium Different sources of manure have different amounts of nutrients UNCE, Reno, Nev.

Cautions for fertilizing with manures  Watch out for weeds and pathogens  Know the manure nutrient content  Consider the salt content Univ. of Oregon

Cautions for fertilizing with manures  Incorporate or apply evenly to avoid smothering plants  Don’t apply on frozen slopes  Avoid leaching nutrients into waterways UNCE, Reno, Nev.

USDA NRCS Nutrient deficiencies

Visual symptoms of deficiencies: Nitrogen

Visual symptoms of deficiencies: Phosphorus

Visual symptoms of deficiencies: Potassium Alfalfa Corn

Visual symptoms of deficiencies: Calcium

Visual symptoms of deficiencies: Zinc

Visual symptoms of deficiencies: Manganese

What we’ve learned  Use soil test results to guide you in amending your soil  Test results are only as good as the sample you collect  Fertilize to meet plant needs, and avoid costly overuse that may pollute water

Part II: Soil Surveys  How to use a soil survey  How to find a map unit  Map unit descriptions  Soil ratings and capabilities

USDA NRCS Where do soil surveys come from, and where can I get one?

Why should we use soil surveys?  Contain practical information for the landowner  Can prevent management mistake  Help determine the potential of your land

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

Soil map units  A map unit describes a soil “type” in the soil survey  “Map-unit descriptions” are found at the beginning of the survey  Soil map units are arranged alphabetically as well as numerically in the soil survey

Soil map unit example 630 Fleischmann gravelly clay loam Soil textural class is part of map unit name Number designation Name given by soil scientists conducting survey

What can you do with the number?  Determine capabilities and limitations  See “Summary of Tables” in the soil survey for additional data on a specific soil use  For our example soil, can we build a septic absorption field?  See Table 10: Lists a severe limitation due to cemented pan

NRCS Web-based soil surveys   Can search by address, or use the map to zoom in  Steps in using the site: –Select area of interest (your property) –View the soil map and learn about the soil properties –Use soil data explorer for additional information –Create a custom soil report

What does all the information mean? USDA NRCS

Soil limitations NRCS, Bozeman, Mont.

 Suitability ratings  Temperature and precipitation data  Freeze dates and growing season  Productivity  Building site development Other information

 Suitability for irrigation  Physical and chemical properties (percent OM, pH, permeability, available water capacity)  Soil surveys can differ in the information they provide.

Restrictive features  Cemented pan  Droughty  Erodes easily  Flooding  Low strength  Restrictive layer  Shrink-swell potential UNCE, Reno, Nev.

Capability classes  Classes I and II—good farmland with few to moderate limitations  Classes III and IV—severe to very severe limitations for growing crops  Classes V and VI—limitations that are impractical to remove.  Classes VII and VIII—very severe, unsuited for cultivation.

Capability classes USDA NRCS

Land capability and yields USDA NRCS

To wrap it up...  Soil surveys are generated by NRCS scientists  They are available in printed form or on the Web  Soil surveys are useful for determining capabilities and limitations of your soils

Additional activity: Use the Web soil survey

Enter an address

Select “Area of Interest”

Go to “Soil Map”

Clip “Area of Interest” to property level

Go to “Soil Data Explorer”

Click on “Vegetative Productivity”

Look at “Yields of Irrigated Crops”

Click on “Sanitary Facilities”

Look at “Septic Tank Absorption Fields”

Generate your custom soil resource report  As you use “Soil Data Explorer” to look at different features, click “Add to Shopping Cart” to add the information to the report  Click on the “Shopping Cart” button to get the report