HS451 Exam 2 - Fertilizers as Sources of Nutrients

What is the most popular form of Solid Nitrogen Fertlizer

urea

What is pre plant fertlization

when you fertilize before planting

What is post plant fertilization

when you fertilize after planting

Controlled release fertilizers

- Most widely used

- release nutrients slowly

what is a starter charge ment to do in fertilizers

intended to provide nutrients for a short period of time immediately after planting.

Post Plant Fertilizer Programs

-fertilizer added after planting

-primary method of application is liquid ferts

Why are water soluble ferts (WSF) best for post planting fert programs

it is a flexible option that can allow you to address changing environmental conditions such as temp, low light etc

Why are controlled release ferts (CRF) not ideal for post planting fert programs

-must be applied after transplanting

-top dressing is the only application method but is costly and labor intensive

Can you do both pre and post plant fertilization if so how should you do it

yes, start with a CRF and then do WSF at low concentrations

Why can a split approach be good

it can help with multiple crops being grown in the same area having different fertilizer requirements but using the same irrigation system

What is a complete fertilizer

It contains N, P, and K

What is an incomplete fertilizer

It is missing either N, P, or K

What is balanced ferilizer

Equal amounts of N, P, and K

do all fert manufacturers prepare ferts with similar pH?

No, so you should plan ahead or pair with a water analysis

How can you control pH

-bicarbonates in water

-limestone addition

-fertilizer concentration (above plant need)

-N source (NH4+ NO3-)

-Acid injection

-Media pH

What does a CaCO3 equivalent with a negative value do

net acidifying effect

What does a CaCO3 equivalent with a positive value do

net basic effect

what does a CaCO3 equivalent with organic nutrients do

generally acidifying

What kind of fert would you want for an inorganic

-controlled release

-dry granule

what kind of fert would you want for an organic

-slow release

-water soluble

What are Inorganic fertilizers

-called synthetic or conventional ferts, go through a manufacturing process

-nutrients generally more plant available

What kind of fert would you want if you are looking for a quick addition to address a deficiency

Inorganic Fertilizer

What are organic fertilizers

- in most cases, only material from plant or animal matter... generally waste streams

-more slowly released

-temperature impacts microbial rate of mineralization

What needs to happen to organic fertilizers to become plant available

nee dto be converted to inorganic forms by microorganisms.

-more slowly released

-temperature impacts microbial rate of mineralization

What are some examples of organic fertilizers

- animal manures

-industrial biomass waste (seaweed extracts)

-rock phosphate

-lime

Are both animal sourced urea and pure (synthetically produced) urea used for agricultural application

No, only animal sourced urea is okay for agricultural application

Historically organic ferts are ...

single source materials used but more commercially blended products are offered to give a complete fertilizer.

How do most organic fertilizers come

as granular or powdered and can be top-dressed, incorporated, or made soluble adding to irrigation water.

Do organic ferts list all ingredients

some organic fertilizers do not list all ingredients which makes it hard to get consistent organic fertilizers

do inorganic ferts list all their ingredients

Yes

What are issues with organic ferts

-difficult to match available supply plant nutrients to plant demand

-by time they are available, they may leach out

In organic ferts ....

-nutrients are not readily availble

-released by microorganism

What is the rate of release of organic ferts affected by

-moisture

-temperature

-microbial species and population density

-soil pH

-herbicides/ pesticides

What is compost tea

recycling waste into fertilizer to create a liquid that you can extract that contains nutrients and beneficial organisms (bio stimulent)

Does aerated compost tea promote aerobic or anaerobic microorganisms

aerobic microorganisms

Does non-aerated compost tea promote aerobic or anaerobic microorganisms

anaerobic microbes

What is the bio-stimulant effect of compost tea

-can improve plant characteristics like plant height, leaf area, etc

-can improve physiological features like chlorophyll content

-probably greatest enhancement is resistance to stresss

Ways to apply compost tea

- foliar spray or as a drench

-typically diluted (1:10 - 1:20)

-preventative is more effective than curative

Controlled release fertilizers ...

-the rate, pattern, and release are controllable

-packaged as a pellet

How are controlled release ferts incorporated

incorporated into substrate or top-dressed

what do controlled release ferts contain

polymer coating that when wet fertilizer is released the release rate depends on substrate temperature and water

what does warm and cold water do to the release of CRF

Warm = fast release and cold = slow

Slow Release Ferts ...

-rate, pattern, and duration are not controlled.

-packaged as a pellet

-

is a slow release fert more or less predictable than CRF

less predictable

fertilizer solubility

maximum amount of fertlizer that can be completely dissolved in water at a given temp

Higher temp = ______________ solubility

greater

What should never be mixed with calcium

phosphates or sulfates