Soil Nutrient Testing
Wisconsin State FFA Environmental and Natural Resources Competition
Contestants for the Wisconsin State Environmental and Natural Resources (ENR) State CDE will be expected
to use information on a Soil Test Report to make suggestions for what fertilizers will be needed to grow
corn/grain, oats, and/or alfalfa. Contestants will also be expected to answer questions pertaining to reading the
data on the Soil Test Report and how to use this data to make informed decisions regarding soil management
and environmental protection. The competition will focus on Nitrogen, Potassium, pH, and Phosphorus, but
may possibly include other nutrients to a lesser extent.
An example is included below; note that the yellow guide boxes will not be on the actual soil test sheet. Sample
questions for competition preparation will be included to help contestants form an idea of what to expect at the
competition itself. These questions may differ from the questions used in the competition but should give an
overall impression of their scope, depth, and general format. Questions will be Scantron multiple choice.
Sample Questions
1. How large is the size of this
plot?
a. 1 acre
b. 8.0 acres
c. 15 acres
d. 800 acres
2. How many pounds of nitrogen
are recommended for a corn crop
on this plot?
a. 0 lbs – it is already too high
b. 6.667 lbs
c. 40 lbs
d. 100 lbs
3. If the anhydrous ammonia used
for nitrogen fertilizing has 82%
N, how many pounds should be
applied for a plot of oats?
a. 2.19 lbs/acre
b. 3.25 lbs/acre
c. 40 lbs/acre
d. 100 lbs/acre
4. Which of the following is true for potassium and phosphorus?
a. Both are low
b. Potassium is high, but phosphorus is low
c. Both are high
d. It depends on the crop – i.e. potassium might be low for alfalfa but high for corn
5. Which of the following supplements should be provided for this test plot?
a. P2O5
b. K2O
c. Urea
d. None of the above – this soil is too high in all these nutrients
6. Complete this sentence: At optimum soil test levels, nutrient application recommendations are…
a. less than the amount of nutrient removed by the harvested crop to prevent runoff
b. equal to the amount of nutrient removed by the harvested crop
c. greater than the amount of nutrient removed by the harvested crop due to losses by leaching
d. dependant on the crop grown and therefore unable to be determined using this report.
7. What is the rotation pH of this plot?
a. Low
b. Optimum
c. High
d. Excessive
8. How is the optimum pH determined?
a. pH strips
b. pH sensors
c. by the target pH of the intended crop
d. by the target pH of the most acid-sensitive crop in the rotation
9. When sampling a field for a uniform recommendation, a sample should…
a. be made of 10 cores taken in a W-shaped pattern
b. use a Global Positioning System to record the coordinates of each sample
c. be thoroughly mixed to make a composite sample
d. both A and C
10. Which of the following recommendations could be offered based on this soil test report?
a. The soil tested in this example is high in both phosphorus and potassium; no further application of
. P2O5 or K2O is recommended.
b. Manure application should be limited or halted
c. Lime is not needed for pH balance
d. All of the above recommendations could be offered based on the soil test report
Answers
1. This plot is 15 acres according to the information given in the upper left
2. According to the Nutrient Recommendations, this plot should get 100 lbs. of N for corn
3. The report recommends 40 lbs total of nitrogen for oats. If anhydrous ammonia has 82% nitrogen, then
40/0.82 = 48.78 lbs ammonia total. Per acre  48.78/15 = 3.25 lbs. ammonia per acre.
4. According to the Test Interpretation Section, potassium (K) and phosphorus (P) are high for all three
crops considered. In fact, they are extremely high, reaching the “Excessive” range and are a potential
source of pollution or watershed contamination at this point.
5. Urea would be recommended for this plot in order to meet nitrogen (N) needs unless alfalfa is being
grown.
6. At optimum soil test levels, nutrient application recommendations are equal to the amount of nutrient
removed by the harvested crop. Additional nutrients can lead to runoff pollution and insufficient
nutrient levels could potentially cause reduced crop performance.
7. The pH of this plot appears to be high.
8. Optimum pH is determined by the target pH of the most acid-sensitive crop in the rotation.
9. When sampling for uniform recommendations, a sample should consist of 10 cores taken in a W pattern
and then thoroughly mixed. A uniform recommendation is for the entire field – coordinates are not
needed unless samples are taken for site-specific recommendations (each part of the field gets the same
application for uniform recommendations, making coordinates meaningless).
10. All of the suggestions would be appropriate for this plot. Phosphorus and potassium are excessively
high. This also explains why manure application should be halted and replaced by a nitrogen-specific
fertilizer such as ammonia (manure contains phosphorus and potassium in varying amounts). According
to the report, lime is not need to reach a recommended 6.8 pH (as listed below the Nutrient
Recommendations table).