Grow Your Own, Nevada! Fall 2012: Gardening in Nevada's Soils

Gardening in Nevada’s SoilsGardening in Nevada’s Soils

Mission Possible!

Gardening in Nevada’s SoilsGardening in Nevada’s Soils

What is healthy soil?

How does soil form?

Soil has many components:

– Textural or structural

– Biological

– Chemical

How can you improve your soil?

OSU Extension Service

Healthy soil has:Healthy soil has:

Good porosity

Good drainage

Good water-holding capacity

Good tilth, meaning they’re easy to work

Lots of organic matter

Lots of organisms

A pH of about 7

Low salinity and sodium levels

How are soils formed?How are soils formed?

A. Miller

Nevada SoilsNevada Soils

Many challenges

– Climate

– Organisms

– Parent material

– Time

– Topography

comcast.net

scioly.org

ucanr.org

It’s not your fault!It’s not your fault!

You didn’t do anything wrong!

We have very young soils geologically

Their youth makes them:

– Highly variable both vertically and horizontally

– Low in organic matter

– Still a work in progress

Compare horizonsCompare horizons


What are soils made of?What are soils made of?

Minerals

Air

Water

Organic matter (humus)

www.statlab.iastate.edu

USDA NRCS

Water = 20 to 30%

Air = 20 to 30%

Mineral Fraction

(sand, silt,clay) = 45 to 50%

Organic Matter = 0 to 5%

““Ideal” composition of a soilIdeal” composition of a soil

Soil Soil minerals minerals textural textural classesclasses

A. Miller

The The dreaded dreaded

soil soil textural textural triangle!triangle!

A. Miller

NRCS, Bozeman Mont.

Textural Textural triangletrianglefor the for the

graphically graphically challengedchallenged

Why determine soil texture?Why determine soil texture?

Soil texture influences:

Ease of tillage

Amount of pore space or porosity

Water infiltration rates

Water-holding capacity

Soil fertility or nutrient-holding capacity

Water Water spreads spreads differently differently in in different different soil soil texturestextures

Deepest penetration

Moderate spread and infiltration

Wide, but more shallow, infiltration

CLAY

SILT

SAND

Sand versus ClaySand versus ClayClay - “Heavy” soil

- High water-holding capacity

- Slow infiltration

- High nutrient-holding capacity

Sand - “Light” soil

- Low water-holding capacity

- Fast infiltration

- Low nutrient-holding capacity

In this experiment, an equal amount of water was applied to three soil types.

NRCS, Bozeman, Mont.

Soil texture affects drainageSoil texture affects drainage

Note the amount of water that drained from the sandy loam soil.



Less water has drained from the silty clay loam soil.



The loam soil drained almost as much as the sandy loam.



Soil texture and drainageSoil texture and drainage

Soil textureInfiltration 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

A. Miller

Water Infiltration Water Infiltration

Where do plants get their water Where do plants get their water from in the root zone?from in the root zone?

Adapted from PNW 475 by A. Miller

Soil textureSoil texture

Sandy soil watering tipsSandy soil watering tips

Emitters close to the plant

Higher volume per hour emitters

Low duration

Increased frequency

Clay soil watering tipsClay soil watering tips

Emitters further from the plant

Lower volume per hour emitters

Higher duration

Lower frequency

Texture by feel: SandTexture by feel: Sand

Adapted from NRCS, Bozeman Mont. by A. Miller

Texture by feel: Loamy sandTexture by feel: Loamy sand


Texture by feel: Loams and claysTexture by feel: Loams and clays


Can you change soil texture?Can you change soil texture?

No, not really!

Add sand to clay – mess!

Add clay to sand – mess!

Texture may limit your plant choices

How can you improve your soil texture? – add organic matter!

Soil organic matter consists of:Soil organic matter consists of:

Living organisms

Dead organisms

Plant matter

Other decomposing organic materials

UNCE, Reno, Nev.

Benefits of soil organic matterBenefits of soil organic matter

Improved water infiltration

Increased water- and nutrient-holding capacity

Formation of soil into stable aggregates

Reduced soil compaction

Nutrient-holding capacityNutrient-holding capacity

Water moleculeWater molecule

Nutrients Nutrients held in the held in the

soil are soil are available available for plant for plant growthgrowth

lesco.com

Soil StructureSoil Structure

Platy structure

Granular structure

www.statlab.iastate.edu/soils/

Soil structure:Soil structure:How particles are grouped together into

stable collections by organic matter “glue,” also called “peds” or soil aggregates

Composition of a compacted soilComposition of a compacted soil

Note the reduced air space in a compacted soil.

Before After

70%50%

Soil CompactionSoil Compaction

Soil compaction Soil compaction

Avoid walking or driving on wet soilAvoid working wet soil


extension.umn.edu

The wetter The wetter the soil, the the soil, the worse the worse the

compaction compaction effect by effect by

mechanized mechanized equipment equipment

Adding organic matter:Adding organic matter:

Improves water infiltration

Increases water- and nutrient-holding capacity

Forms soil into stable aggregates

Reduces soil compaction

Also – feeds soil biota!

USDA NRCS

The living soilThe living soil

wormworm

USDA NRCS

Add organic matter to your soilAdd organic matter to your soil


What kind of organic matter?

Composted or well-rotted OM

What about manure?


Uncomposted manure can be high in salts (burns plants and seeds) and can contain weed seeds, diseases, and insect eggs and larva.

Erosion ControlErosion ControlAnother method to manage soil

Soil takes time to form – you don’t want to lose it!

Keep a cover on the soil – plants, mulch, etc.

Provide for drainage paths and armor them to reduce the potential for erosion

Protect slopesProtect slopes

Redirect the rainRedirect the rain

Check irrigation oftenCheck irrigation often

Chemical Properties of SoilChemical Properties of Soil

pH – potential of Hydrogen

EC – Electrical Conductivity

Nutrient content (plant nutrients)

pHpH

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

pH – Potential of HydrogenpH – Potential of HydrogenMeasure of the amount of hydrogen

Negative logarithm of hydrogen ion activity - 1 pH point is a ten-fold change

pH of 7 = 1.0 x 10-7 hydrogen ions equal H+ and OH- ions

pH of 3 = 1.0 x 10-3 Hydrogen ions more H+ than OH- acidic

pH of 10 = 1.0 x 10-10 Hydrogen ions more OH- than H+ alkaline or basic

Soil pH Soil pH and and

nutrientsnutrients

Adapted from www.soil.ncsu.edu by A. Miller

Widest part of the bar indicates maximum availability

Can I change my soil pH?Can I change my soil pH?

Not really – our soils are alkaline

Limestone (calcium carbonate) buffers our soils

CaCO3 + 2HCl = 2Cl- + Ca+2 + H2O + CO2 (gas)

Can add sulfur, but takes time to lower pH and change is not always not permanent

EC or Electrical ConductivityEC or Electrical Conductivity

Measures how well soil conducts an electric current

Salts that dissolve in water conduct electricity

Plants need some “salts” – these are nutrients

Very high EC = high salt content

If salt contents are high, it can interfere with plant growth

Classifying salt-affected soilsClassifying 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

What to do about What to do about salt-affected soil?salt-affected soil?

If you have tested and find you have salt-affected soil:

– Flush the soil with water to wash the salt down below the growing zone

Problem:

– High water tables, poorly drained soil and high salt content irrigation water are often the cause of or contribute to high salinity

Managing salt-affected soilsManaging 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

If a serious problem, go to raised beds with good drainage

Plant nutrientsPlant nutrientsSubstances necessary for plant growth

Plants make their own food – these are the vitamins and minerals plants need to make their food and to grow

Excess or improper use of fertilizers may result in plant damage and water pollution

Split into two groups, based on the amount of the nutrients the plants need to survive and thrive

MacronutrientsMacronutrients

N = nitrogen

P = phosphorus

K = potassium

H = hydrogen

O = oxygen

C = carbon

Ca = calcium

Mg = magnesium

S = sulfur

MicronutrientsMicronutrients

Fe = iron

Mn = manganese

Zn = zinc

B = boron

Mo = molybdenum

Ni = nickel

Cu = copper

Co = cobalt

Cl = chlorine

What do the nutrients do?What do the nutrients do?

Carbon, Hydrogen, OxygenCarbon, Hydrogen, Oxygen

Building block of organic molecules

From the air and water

Generally not deficient (we’d be in trouble too!)

These things cycle, just like the water cycle

Nitrogen, NNitrogen, N

Constituent of amino acids, which are building blocks of proteins and enzymes.

Also component of nucleic acid and chlorophyll

Generally, this is the limiting factor or nutrient in plant growth.

Complex cycle, since it is a big constituent of all life on the planet - atmosphere is 78% nitrogen gas or N2

Nitrogen, NNitrogen, NDeficiency symptoms:

– Slow growth, stunting, chlorosis (yellowing)

– Begins with older tissues; nitrogen is mobile and moves to younger tissues (N mobile)

Excess N symptoms

– Excessive vegetative growth – dark green

– Delayed maturity, few fruit

Visual symptoms of deficiencies: Visual symptoms of deficiencies: NitrogenNitrogen

http://agri.atu.edu

Phosphorus, P or PPhosphorus, P or P22OO55

Most important plant function is the storage and transfer of energy (ADP and ATP (adenosine di- and triphosphates))

Also component of DNA and plays a critical role in cell membranes

Absorbed by plant roots form the soil as the ion H2PO4

-1 and HPO4-2

Does not really move much in soil, just changes form, which may make it unavailable to plants – BUT will move with the soil – prevent erosion

Phosphorus, P or PPhosphorus, P or P22OO55

Deficiency symptoms:

– Slow growth, stunting, purplish or dark green color on foliage

– Interveinal chlorosis (leaves are yellow on the upper surface, but remain green at the base)

– Delayed maturity, poor fruit or seed development

– Does move in plants, so deficiency symptoms show in the older leaves

Excessive P symptoms:

– Can interfere with micronutrient absorption

Visual symptoms of deficiencies: Visual symptoms of deficiencies: PhosphorusPhosphorus

http://agri.atu.edu

Phosphorus deficiencyPhosphorus deficiency

Potassium, KPotassium, KImportant in many plant function, such as

carbohydrate metabolism, enzyme activation, and protein synthesis

Essential for photosynthesis, starch formation and N fixation in legumes.

As a result of these functions, a good supply of potassium produces plump grains and large tubers or roots

Exists as ion (K+) in plants

Helps plants adapt to environmental stresses

Potassium, KPotassium, KDeficiency symptoms:

– Slow growth

– Leaf tip and marginal burn and necrosis on older leaves

–Mobile in plants, so older leaves show the deficiency symptoms

–Weak stalks, small fruit, shriveled seeds

Excessive K symptoms:

– Light green foliage, can look like Ca and Mg deficiency

Visual symptoms of deficiencies: Visual symptoms of deficiencies: PotassiumPotassium

Alfalfa

Corn

http://agri.atu.eduhttp://ipm.iastate.edu

Sulfur:Sulfur:

Essential for production of proteins, enzymes and vitamins

Helps in chlorophyll formation

Improves root growth and seed production

Helps with vigorous plant growth and resistance to cold

Sulfur:Sulfur:


– Yellowing on new leaves first, starting at tip of leaf; older leaves stay green

– Sulfur is not mobile in plants, so new growth shows the deficiency symptoms

– Stunted growth

Excess sulfur generally not a problem

Sulfur deficiencySulfur deficiency

Calcium, CaCalcium, Ca

Essential component of plant cell walls and membranes

Regulates cell permeability and cell integrity

We have adequate Ca in our soils

Calcium, CaCalcium, Ca


– Reduced terminal growth of shoots and roots

– Symptoms show in new growth first – Ca+2 is not mobile in plants.

Excess Ca+2 symptoms

– Interferes with other nutrint uptake

– Increases soil pH

Calcium deficiencyCalcium deficiency

Magnesium, MgMagnesium, Mg

Part of chlorophyll molecule and many enzymes

Aids in mobility and efficiency of phosphorus

Magnesium, MgMagnesium, MgDeficiency symptoms:

– Interveinal chlorosis (leaves are yellow on the upper surface, but remain green at the base) or marginal yellowing with mid rib remaining green (tree pattern)

–Marginal necrosis

–Mobile in plants, so older leaves will show symptoms first (it moves to younger leaves)

Excess Mg symptoms

– Interferes with Calcium uptake

Mg deficiencyMg deficiency

MicronutrientsMicronutrientsRequired in very small amounts

Essential components in enzymes, chlorophyll, DNA, etc

Deficiencies are rare – generally it is the macronutrients that cause the observed problems

Iron and zinc deficiencies are most common problem in our area

Iron, FeIron, Fe

Interveinal chlorosis (veins remain green) and reduced growth

Common in our soils due to pH – iron is there, but not in a form plants can readily use

Not mobile in plants, so symptoms on young leaves

Certain plants more susceptible

Visual symptoms of Fe Visual symptoms of Fe deficiencydeficiency

Manganese, MnManganese, Mn

Interveinal and marginal chlorosis, but no green vein areas, as with Fe

Excess leads to Fe deficiency

Not mobile in plants, so effects show first on young leaves

Essential in vitamin C production, citrus plants require foliar spray of Mn and Zn

Visual symptoms Visual symptoms of deficiencies: of deficiencies:

ManganeseManganese

http://agri.atu.edu

Zinc, ZnZinc, ZnInterveinal chlorosis, decrease in stem

length, rosetting of terminal leaves

Not mobile, so young leaves and other terminal growth areas are affected first

Common deficiency in many crops

Excess Zn symptoms?

Visual symptoms of deficiencies: Visual symptoms of deficiencies: ZincZinc

http://agri.atu.edu

Boron, BBoron, BNot remobilized in plants, so affects new

growth first and can cause death of terminal growth areas or malformed, cupped leaves

Rare deficiency – we more commonly worry about excess B!

Excess can cause marginal necrosis

Generally, excess means soil has other problems, like salinity issues

Boron deficiencyBoron deficiency

Boron toxicityBoron toxicity

Copper, CuCopper, Cu

Deficiency symptoms are stunted growth, poor pigmentation and death of leaf tips

Affects new growth

CAUTION! Always test if you suspect Cu deficiency – Cu can be highly toxic.

Excess can cause reduced growth and necrosis

Chlorine, ClChlorine, Cl

Rare deficiency

Excess can cause poor growth and marginal necrosis

Molybdenum, MoMolybdenum, Mo

Deficiency similar to nitrogen – Mo plays key role in N use in plants

Stunting, chlorosis, reduced yield

Affects older leaves – like N, it is mobile in plants and moves to younger growth

Excess symptoms?

And last, but not least And last, but not least Nickel, NiNickel, Ni

Movement in soil poorly understood. Complex chemistry and forms many ions

Deficiency forms leaf tip necrosis

Excess interferes with Fe and Zn uptake, chlorosis symptoms

In general…In general…

Ca and B show symptoms on terminal buds

Fe, Mn, S and Cu show symptoms on young leaves (not mobile in plants)

N, P, K, Mg, Zn and Mo show symptoms on old leaves (mobile in plants, they will move to younger leaves)

How do we add nutrients?How do we add nutrients?

Minor amounts in compost

Minor amounts in soil “amendments”

Generally added as fertilizer

Types of fertilizersTypes of fertilizersChemical fertilizers

Organic fertilizers or amendments (bone meal, compost, manure, etc.)

www.farmphoto.com

Complete vs incomplete fertilizerComplete vs incomplete fertilizer“Complete” fertilizers contains the top 3

nutrients, like 16-16-16 general fertilizer:

– Nitrogen (N)

– Phosphorus (P)

– Potassium (K)

– 4th number, if present, is Sulfur (S)

“Incomplete” fertilizers do not contain the top 3 nutrients, like Ammonium Sulfate 21-0-0

What’s in What’s in the bag?the bag?

WAY TO GROWFERTILIZER

28 – 14 - 5GUARANTEED ANALYSIS

Total nitrogen 28% 6% Ammonium nitrogen 14% Urea nitrogenAvailable phosphoric acid 14%Soluble potash 5%

Derived from sulfur-coated urea,etc.

Product name

NPK formula

Nitrogen content

Phosphorus content

Potassium content

Specific sources

A word about gypsumA word about gypsumGypsum is CaSO4

.H2O

Good source of Calcium and Sulfur

Good for Sodium-Affected Soils

NOT a panacea for clay soils!

Too much Ca can interfere with chemical balance in soil and can contribute to a magnesium deficiency and interfere with other micronutrient availability

How do How do I know I know what to what to add to add to

my my soil???soil???

A. Miller

Test Test your your soil!soil!

What should I test for? What should I test for?

Soil textural analysis

pH and salts

Soil nutrient content

Fertilizer recommendations

Call your local extension office for a list of soil testing labs

What information does a normal What information does a normal soil test provide?soil test provide?

Call the Lab FIRST!Call the Lab FIRST!

Find out what they test for

Find out if they have package deals

Find out how much sample they want you to take

Find out how they want the sample delivered to them

Call UNCE 784-4848 for list of labs

How to take a sampleHow to take a sample

First, select the site. Your soil sample should represent only one soil type or soil condition.


Each sample should consist of sub-samples taken from about 5-15 locations within the same soil type or sampling area.



Use the “slice” method for a representative sample.

UNCE, Reno, Nev.


How can I manage my soils to How can I manage my soils to improve them?improve them?

Increase the organic matter content by: • Adding compost and well-rotted manure

Avoid compaction by:• Reducing tillage of wet soils

• Reducing traffic on wet soils

• Establish paths

Maintain cover with vegetation or mulch to reduce potential for erosion

Fertilize when needed

Documents

Grow Your Own, Nevada! Fall 2012: Gardening in Nevada's Soils