soil

Soils• SOIL is a dynamic system of living and

nonliving components.

• DIRT is soil out of place

Soil components

• Mineral

• Organic

• Water

• Air

• Living Organisms

Mineral components

• Derived from rock

• The nature of the soil depends on the kind of rock and the degree of weathering

• Mineral soil is quite permanent

Mineral components

• Texture- the name of a soil is based on the mineral components if soil is less than 20% organic , it is called a mineral soil.

• Particle size:– coarse SAND .2 - 2 mm– SAND 20 - 200 um (microns)– SILT 2 - 20 um– CLAY less than 2um

The name of a soil is based on its mineral components.

Water

Soil structure

• How soil clumps or aggregates– Determines pore space– Aggregates are classified by shape

• Flat, prism-shaped, block-like, plate-like, and spheroid

• Spheroid is optimal but the clay in Duluth is plate-like

Physical forces that result in aggregation

• Freezing and thawing

• Wetting and drying

• Action of worms, and other organisms

• Root growth

Organic componentsHumus, litter, duff

• Plant, animal, bacterial, fungal remains

• Always disappearing due to decay

• % of organic matter depends on– Rate of accumulation– Rate of or resistance to decay– Climate

• Cold /dry = minimal decay• Hot/ damp = fast decay

Importance of Organic material

• Holds available minerals and nutrients

• Increases water holding in sandy soil

• Increases drainage by aggregating clay

• Inhibits erosion

Sources of organic material for the garden

• Manure from farm animals ( composted)

• Green manure crops

• Sewage sludge

• compost

Soil Water

Capillary Water = available to plants

• Maximum Cap water = field capacity

• The amount of water available to plants is determined by:– Texture of the mineral component AND

– % organic material

Water holding capacity = field capacity - wilt

» SANDY SOILSILT/LOAM

• FIELD CAP 7.6 30.4• % WILT 3.7

20.6

• AVAILABLE H2O 3.9 9.8

• Soil texture and % organic mater determines the amount of water available to plants

Soil Atmosphere

• High in CO2, low in O2

• O2 necessary for cellular respiration in roots

• Aquatic plants have special adaptations

Soil Organisms

• Bacteria, Fungi, algae = 75% of the dry weight of organisms

• Worms = 12% dry weight

• Invertebrates = 13%

• A– Leaching

– Most plant growth

– Humification

• B– Deposition

– Less organics

– N+K

C.

Parent material

Horizons

NutrientsMacronutrients

• % dry weight of plant• Ca .5%• Mg .2%• S .1%• O 45%

• H 6%• C 45%• N 1.5%• P .02%• K 1.0%

NutrientsMicronutrients .01% to .00001%

• % dry weight of plant• Mo• B• Fe• Cl

• Cu• Zn• Mn

C HOPKINS CAFÉ MIGHTY GOOD, BUT MANY

MORE PREFER CLARA’S ZANY CUP

Nitrogen Fixation

Oats as a green manure crop

Soil fertilization

• Chemical N:P:K – comes from industry– Very concentrated– Easy to apply

• Organic– Comes from animals plants or rocks– Without a lot of processing– Low nutrient, heavy– Comes with a lot of organic material bulk

Fertilizer analysisis the % by weight of a nutrient

• N in the form of elemental Nitrogen

• P is Phosphorus as P2O5

• K is Potassium as K2O

• All commercial fertilizer must have N:P:K: on the bag.

analysis ratioN P K33 0 0 Ammonium Nitrate 1:0:02 1 2 Sheep Manure 2:1:225 5 10 Lawn Fertilizer 5:1:210 10 10 Vegetable Fertilizer 1:1:1

The ratio is important, grass needs lots of N, veggies will not produce if they get lots of N.

A soil test will tell you what your soil is lacking

• Go online or Call the ag extension office and get a soil test kit

• Follow the directions, send it in, and the results take about 2 weeks.

• Add the nutrients as listed on your test report

• Look at tables on pages 29s-31s

Changing pH of soil

If soil is too acid

• Lime (agricultural) not Hydrated

• Organic ( Dolomitic Lime)

If soil is too alkaline

• Sulfur • Organic – Peat moss (

pH 4.5)

Changing pH of water

• add baking soda • Add an acid ( lemon juice or vinegar)

Changing soil texture

• To loosen clay– Add organic material to

create aggregates to increase drainage

– Add gypsum– Add sand– Work the soil when it is a

the right moisture level not too wet or dry. Soil should not stick to the shovel, and a handful should break apart

• To make sand retain water– Add organic material– Add clay ( it can be bought

as a powder in bags)– Add an organic mulch to

the soil surface

If your soil is too wetbecause the water table is too

high in spring• Tiling is placing drain tile

in the ground it should come out down hill.

• Raised beds

Mixing potting soil

• Soil in a pot needs to be mixed with different textures to allow air and water spaces

• Common horticultural soil mixes have Peat Vermiculite and Perlite added

• Soilless mixes have no actual loam added

Peat

• Is the most common organic soil component, it does not need to be pasteurized. Peat has some “politics”.

• An alternative is Coir

Vermiculite

The ore is dried then flash heated to 1000 degrees F

Perlite/ Krum

Perlite starts out as a volcanic glass and is heated to 1560-1650F and poppedIt is used as insulation and soil additive.

Fertilizer calculations

• 32s-33s• You need to figure out

how much of what fertilizer and how to apply it and when to apply

• How big is the area where fertilizer needs to be applied.

• According to the soil test result how many pounds of your chosen fertilizer do you need?

• Are you going to broadcast or side dress

• Or split the application spring and fall?

How to apply

How to apply

• Broadcast and till is quite common for a city garden. This happens just before transplant.

• Side dress or band is what happens when you feed mid season. The fertilizer does not touch the plants.

• Feeding trees usually happens as the buds swell in spring and depending on the tree thy can be foliar fed as fruit is developing.

Fertilize in two or more directions to get even coverage

Feeding Trees