Question - What to apply each time of the year, general info

[Supper Grassy]

I don't set foot down here much but i need to write a chemistry paper about how lawn care relates to chemistry and the first thing that i though of was fertilizer.
so what npk fertilizer do you put down for your treatments
what do the npk numbers mean and how high do they go?

[RigglePLC]

Scroll up 6 inches and click the Agrium site. You will get most of the basic ideas there. Talk to a few fert salesmen.

We all use something different depending on our preference, local conditions, and local univ reccomends. Gold courses aproach it different. Sports fields have there own ideas about what is best. High school. College. Pro sports. Each has unique ideas.

[Smallaxe]

Soil chemistry would be a sensible relation to chemistry in general. Application rates have more to do with ol' wives' tales than any kind of science.

What happens to the NPK once it hits the ground until the time it is gone?
Where does it go?

Answer some real questions. Education is dumbed down to the point that 'chemistry' refers to application rates? established by fertilizer salesmen?

[foreplease]

The NPK numbers on the bag - not sure if that's what you mean or if you mean soil test results, where N is normally not reported - represent what percent of the total bag weight is each of those elements. 21-4-11 bag weighing 50# contains 10.5 # N, 2 # P, 5.5 # K

Most turf people apply with a total amount of N per thousand square feet in mind for the year. Many, such as myself, work within a ratio between those NPK numbers over the course of the year, all sources and applications considered. Usually, the amount of N people want to apply governs the total P and K if the applicator wants to stay within the ratio he/she likes. I prefer a 4:1:2 ratio for the year. Sometimes these numbers are arrived at by beginning with the Potassium number for the year instead of Nitrogen. Soil tests and expected type of use for the turf are things that could push one in that direction. I work on athletic fields where wear tolerance and recuperative potential are important. Others, such as those Riggle mentioned, have different criteria, such as appearance (color and density), drought tolerance, growth rate, newly seeded yards, etc.

The sources of N, especially, are important in terms of type and duration of response, burn potential, likelihood to change soil pH, etc. Most of us use different N sources throughout the year.

There is a relationship between soil texture and the Cation Exchange Capacity (CEC). Generally, if your soil has trouble retaining water - which is another way of saying well-drained in my world ha ha - grass growing in it will have more difficulty obtaining nutrients from the soil. On those soils smaller more frequent applications may work better or waste less.

Application rates absolutely have to do with science. People who put down synthetics (and bagged organics) can tell you precisely what was put down. More than that, they can hit a target rate with a fair degree of accuracy. The “compost does a soil good” school of thought has its place but you have to put down an awful lot of material (which you will see people struggle to accomplish if you look around this site), it is often of unknown source and analysis, meaning they can’t tell you how much NPK was put down, or how much its microbes are going pull from the soil, or when it will begin working, or stop working, or how it may work compared to the last time under similar circumstances. Not too scientific.

[Supper Grassy]

ok thanks!!!
what does each of the NPK cause to happen
i know nitrogen means greener and grows faster but i am unsure of the rest

[foreplease]

I think we have reached the point where you should do some research for your paper. Look for university research - something you can cite and rely on.

[Supper Grassy]

Ok, Thanks for all of your help

[Smallaxe]

It really kind of explains why pre-m, forms a barrier, and there is no such thing as N burn for unirrigated lawns.

[Kiril]

I don't set foot down here much but i need to write a chemistry paper about how lawn care relates to chemistry and the first thing that i though of was fertilizer.
so what npk fertilizer do you put down for your treatments
what do the npk numbers mean and how high do they go?

Everything can be related to chemistry in one way or another, including something as basic as mowing height.

[Kiril]

Application rates absolutely have to do with science. People who put down synthetics (and bagged organics) can tell you precisely what was put down. More than that, they can hit a target rate with a fair degree of accuracy.

But can you say with certainly what happens to that fert. once it moves into the soil?

The “compost does a soil good” school of thought has its place but you have to put down an awful lot of material (which you will see people struggle to accomplish if you look around this site), it is often of unknown source and analysis, meaning they can’t tell you how much NPK was put down, or how much its microbes are going pull from the soil, or when it will begin working, or stop working, or how it may work compared to the last time under similar circumstances. Not too scientific.

Compost is used primarily to build a better soil and to promote a healthy and active soil ecology. What ever NPK comes with it is secondary to these objectives. If you want to know exactly what you are putting down in terms of nutrients, then have it tested, if a test is not already available. This is no different than any other source of organic nutrients. With respect to when or how much, the environment dictates this, as it should be.

Keep in mind, for the vast majority of people here we are talking about residential and commercial turf, not sports turf or Ag.

[foreplease]

But can you say with certainly what happens to that fert. once it moves into the soil?

Keep in mind, for the vast majority of people here we are talking about residential and commercial turf, not sports turf or Ag.

Well, I know what kind of response to expect and how the soil test results change from year to year, or every couple. It’s either being mined out, leached through, bound to the soil and not useable or not needed, or lost to the atmosphere.

Right, exactly why I came clean with what I do. Most homeowners are not equipped to spread thousands of pounds of compost, even though it might be a good idea, and work it into their turf satisfactorily.

[Kiril]

Well, I know what kind of response to expect and how the soil test results change from year to year, or every couple. It’s either being mined out, leached through, bound to the soil and not useable or not needed, or lost to the atmosphere.

I believe the same thing can be said about an organic program, with possible exception to predicting an immediate "fertilizer" response, and even then with the appropriate testing/analysis/experience. I assume by "response" you mean a visual one (i.e. NTEP rating), which is questionably scientific and highly subjective unless you are using some pretty expensive equipment (ex. a NDVI meter).

I can make a manure tea and get a predictable short term N response. The compost I use gives a predictable short term N response, as well as blood meal and any other quick release organic N.

Knowledge of the soil and site conditions, your amendments (synthetic or organic), and environmental conditions allows you to predict both short and long term response. The more testing you do and data you collect, the more accurate your predictions will be .... and that applies to both organic and synthetic programs.

Right, exactly why I came clean with what I do. Most homeowners are not equipped to spread thousands of pounds of compost, even though it might be a good idea, and work it into their turf satisfactorily.

A wheel barrow, shovel, and rake is all you need, especially given many people are probably sitting on an acre or less. Furthermore, being properly equipped or not is no excuse for poor land stewardship. Fact of the matter is, the reason why people have so many problems with their landscapes is because the soils are in piss poor condition, in large part due to poor management practices in conjunction with the use of only synthetics with little or no OM inputs.

The point here is most soils need organic matter, including sports turf and Ag. Compost will provide that in the most economically and beneficial way, leading not only to a better soil, but also a system that will require fewer inputs (ferts, pesticides, water, etc...) over time.