Soil Amendments and Fertilizers What is a soil amendment and what is a

fertilizer? Soil amendment – is a material that primarily

adds _________________ matter to the soil Organic matter important for soil organisms Does contain nutrients needed by plants

Fertilizer – is a material that primarily adds _________________ to the soil

Some fertilizers may contain organic matter May not have all the nutrients that plants need

Soil Amendments The impact of soil amendments on the soil and

vegetable plants is dependent on the amount of ____________ and nitrogen in the amendment

Carbon to nitrogen ratio Normal carbon-to-nitrogen (C:N) ratio in soils is

about _____:_____ Adding organic matter alters this ratio Problem

Materials with too ___________ a C:N ratio will tie up nitrogen making it unavailable for vegetable plants

Soil organism use the carbon as an energy source and the nitrogen for ________________

Soil amendments

Examples _______________

Is a living culture of organic matter similar to yogurt

Rule: anything that is entirely organic in origin can be composted

Peat ____________ Sawdust

C:N ratio of 450:1 Green manures

Soil amendments – Green manures

Introduction _____________ manures – are rapidly growing

plants that are incorporated into the soil before planting the vegetables

Advantages Can supply ____________ to the vegetable plant

Some green manures are legumes _____________ loss of nutrients Makes plant nutrients available to the

vegetable crop Improves the ___________

Soil amendments

What is a legume?

Soil amendments

What is a legume? It is a plant that has nodules on their

roots which contain ___________________ bacteria

The bacteria are able to convert nitrogen in the air into a form that plants can use

Were used as a ____________ source before synthetic fertilizers were widely available

Soil amendments - Cover crops Cover crops – are plants that are rapidly

growing and after they die they are left on the soil surface

Purpose Protect the soil from _______________ Tie-up nutrients Prevent ____________ growth

Cover crops are most commonly fall-seeded Examples of plants used

Cereal ______________ _______________ vetch

Soil amendments/ Fertilizers

Animal manures Are intermediate between a soil

amendment and a fertilizer Vary greatly in their ___________

composition Caused by:

Animal Feed used Type of litter or bedding Degree of composting or decomposition

Must be _________________ before use

Animal Manures Problems with manures

May contain harmful or undesirable contaminants

_________ and other harmful bacteria may be in fresh manure

Manures are _________ in nutrients compared to synthetic fertilizers

The most common commercially available types of manures ____________ manure Chicken (Poultry) manure

Animal manures

Table: Typical Composition of Manures

Source _____ P2O5 K2O

Alfalfa hay

_____ 0.5 2.1

Cow manure

0.6-2.1 0.7-1.1 2.4-3.6

Composition (% Dry Matter)

Fertilizers

Introduction Plants take up the same nutrients

whichever category of fertilizer is used

Several categories of fertilizers ____________ versus synthetic Rapid versus slow _____________

Solid versus liquid

Organic Fertilizers

Advantages Nutrients are released ________________

May improve the taste of the vegetable Nutrients are less likely to leach

May benefit the soil microorganisms Problems

Are low in potassium “Semi-organic” or “________________ based”

Cost per unit of nutrient

Organic Fertilizers

Rapid release forms of plant nutrients Most of the plant nutrients are

available soon after application of the fertilizer

Most organic examples are general compound fertilizers contain a number of ________ nutrients

Organic Fertilizers – Rapid release

Animal byproducts Source are

processing plants or slaughterhouses

Include Dried ________ Fish meal _________ meal

Organic Fertilizers – Rapid release

Bone meal Excellent source

of phosphorus and _____________

Problem Might transmit

diseases Mad cow ____________

No evidence that has occurred

Organic Fertilizers Slow release

Are either plant byproducts or ground rock materials

Release nutrients over a growing season or more

Examples _______________ meal Rock __________ Greensand

Organic Fertilizers

Slow release Plant byproducts _________ meal

Rich in minor nutrients

Contains 60 to 70 different chemical compounds

Organic Fertilizers

Rock phosphate A finely ground

natural rock powder There are two kinds:

Hard rock phosphate __________ phosphate

Potassium Rock potash

(greensand) Wood ashes

Are very ____________

Organic Fertilizers Liquid fertilizers

Fertilizer nutrients are dissolved in __________ Advantages

Easy to apply The nutrients are available immediately

Problems Can injure plants Easy to over apply May ______________ or contaminate surface waters

Organic Examples ________________ teas Manure teas Seaweed extract

Typical Composition of Some Organic Fertilizers

Fertilizer N P2O5 K2O

Blood 13.0 2.0 1.0

Bone meal

_____ 15.0 ----

Fish meal

10.0 6.0 ----

Greensand

---- ---- ____

Composition (% Dry Weight)

Synthetic Fertilizers

Introduction Many “_________________” fertilizers are

derived from natural deposits The nutrients are concentrated Converted into a form that is readily

available in the soil

Synthetic Fertilizers

Advantages Easy to apply ________________ Are readily available

Disadvantages May easily be over-applied Can lead to ___________ build-up May have adverse effects on soil organisms Can be leached from __________ zone

Synthetic Fertilizers

Nitrogen fertilizer Most important component of synthetic

fertilizers Synthesized from nitrogen in the air

Offshoot of World War II ammunition production Production is very _________________ intensive

Forms of nitrogen fertilizer Ammonia _____________ Urea