Applying the N Cycle processes to calculate N guidelines for optimum yielding
crops and minimal losses to the environment
Consider corn as an example. To calculate the N requirement,
start by factoring in the following crop N demands and sources of N.
First, the corn yield potential is determined based on a research database of corn yields for the many different soil types found in New York State. The corn yield potential will vary depending on soil type and drainage. The yield potential helps set the gross N requirement for the crop.
Next, quantify the N available from the mineralization of soil organic matter. This factor is also based on research trials and depends on soil type and drainage.
The next N credit to factor is the N available from killed sods. The amount of N availabe depends on the legume composition of the sod and the years since the sod was tilled under.
The final factor to consider is the nutrient uptake efficiency or "fertilizer efficiency". It's also dependent on the soil type and extent of artificial drainage.
When it's all packaged in an equation, it looks like this...
The result is used to calculate how much manure and/or
fertilizer to apply in the upcoming growing season for a healthy corn crop
and minimal losses.
Step through the Corn N Guidelines in the following pages
to investigate each of the factors that help make a plan for efficient N
As you scroll through the Corn
N Guidelines, answer the questions (and take notes if helpful) on the Corn
N Worksheet. You'll have a chance to work with this equation interactively
at the end of this section.