Agriculture Reference
In-Depth Information
Soil temperature in degrees Celsius. If your
thermometer reads in Fahrenheit you can convert from
Fahrenheit to Celsius:
T =
Celsius =
Percent CO2 as reported in the appropriate column on
the Draeger tube
P =
Grams of CO2 − C per Square meter per Day
= ((T - 273)/273) x (P - 0.035) x 10.4
Analyzing Macro-nutrients and pH
If you have ever seen a series of numbers on a bag of
fertilizer, such as 10-10-10, 5-10-5 or even 45-0-0, those
numbers are the NPK rating of the fertilizer. They mean that
100 lbs of that fertilizer will supply the stated number of
pounds of nitrogen, phosphorus or potassium. So 100 lbs of
5-10-5 fertilizer will provide 5 lbs of nitrogen, 10 lbs of
phosphorus and 5 lbs of potassium. Because other
macro-nutrients such as calcium, carbon and water are
supplied as part of liming, watering or simply from the air,
these three major nutrients are the ones described on the bag.
Depending upon the type of fertilizer, the rest of the product
may be utterly inert, or it may contain other nutrients as well.
Soil analysis is a very complex field and there are two major
competing schools of thought regarding what is important.
The sufficiency method is used by most laboratories and
commercial farms. It tests for the major macro-nutrients:
nitrogen, phosphorus and potassium, along with pH and a
