Colorado Agriscience Curriculum
Section: Plant & Soil Science
Unit: Soil Management
Lesson Title: Lesson 3: Fertilizer Recommendations and Fertilizer Adjustments Lab
Colorado Agricultural Education Standards:
Standard 10.9 The student will demonstrate an understanding of soil fertility and its effect on crop production.
Enabler 10.9.10 Make fertilizer recommendations.
Colorado Science Standards:
Standard SCI7.0 Students know and understand common connections between scientific disciplines as well as connections between science and other academic areas.
Competency 7.01 Use graphs, equations or other models to analyze systems involving change and constancy.
Competency 7.06 Use skills and knowledge learned in other disciplines to communicate about science
Competency 7.07 Apply skills and knowledge learned in science to other content areas.
Student Learning Objectives (Enablers)
As a result of this lesson, the student will:
1. Use given data to make fertilizer recommendations for crops in Colorado.
2. Be able to complete the fertilizer recommendation part of the Colorado Land Classification CDE.
Time: Instruction time for this lesson: 50 minutes for lesson and 50 minutes for the lab.
Resources:
Land Judging in Colorado. Colorado State University, Dept. of Soil and Crop Sciences, Ft. Collins, CO 2004.
Tools, Equipment, and Supplies
Colorado Land Judging Manual
Writing surface
Writing materials
Color overheads/Overhead projector/Computer with Powerpoint and projector
Key Terms. The following terms are presented in this lesson and appear in bold italics:
Nitrogen, Phosphorous, Potassium, Zinc, Iron, Organic Matter, Soluble Salts
Interest Approach
Divide the class into manageable sized groups and have them come up with a recipe for baking cookies with the following information given.
Divide into groups of four by numbering off. Move quickly and quietly to your groups. 1’s on the north side, 2’s to the east, 3’s to the south, and 4’s to the west.
Show Powerpoint slide #1
Wait until I say the word “bake cookies” to get started. Your group is going to bake some cookies. On the screen you will see some ingredients and you must come up with a recipe and then tell me if the amount of each ingredients is adequate, deficient, or there is too much of an ingredient. Ready, BAKE COOKIES!
Give a warning at 1 minute, then have the groups share their recipes with the class and quiz them about the ingredients and which ones were adequate, deficient, or excessive.
Show powerpoint #2 to show them the recipe and which ingredients were adequate, deficient, or excessive.
Summary of Content and Teaching Strategies
Objective 1. Use given data to make fertilizer recommendations for crops in Colorado
We have been talking about and testing for N-P-K, pH and soil organic matter, now that we know how to test for these macronutrients and we have some values of what is in our soil samples, what should we do with the information? Just as in our cookie example, we want to make something, and that is a successful crop. In our cookie example we didn’t know if we had enough of each ingredient, similarly with our soil we don’t know if we have enough of each nutrient, the correct amount, or excessive amounts. So we need to make some recommendations on how much nutrients to add in order to grow a successful crop.
Show powerpoint slide #3 and review objectives.
We can take our data and apply it to making fertilizer recommendations. Do we apply the same amount of nutrients to all crops? No, we have different tables that will help determine how much of each nutrient is needed to attain certain production goals. First we must select a crop to fertilize. Who can guess what production crop is most widely grown in Colorado? Corn is the answer. We can use any crop but let’s start with corn.
The crop tables are for: Irrigated corn, and corn silage, other crop tables can be found in the Land Judging in Colorado Manual and in the next lesson.
Show powerpoint slide #4
Looking at this table for Nitrogen recommendations for Irrigated Corn, we need to know at least two pieces of information what are they? (Accept answers). Awesome!! You are correct we need to know the nitrogen soil test (ppm-parts per million), and the organic matter.
Using the Nitrogen test levels found from before and a chosen Organic matter content, have the students find the recommendation on the table. Give a couple of different scenario’s and call on different students to check for understanding. DO NOT WORRY ABOUT THE NITROGEN ADJUSTMENTS FOR YIELD FOR NOW, THAT IS THE NEXT LESSON.
Using our established soil test for nitrogen of 26 ppm and a organic matter of 1.9% let’s find the best recommendation.
Even if they “get” this have the students use their fingers to find the answers on the chart. This assists with tactile learners. Call them up to the board if using the powerpoint or overheads, have them do it individually if you give out fertilizer recommendation packets.
Using your left hand put a finger on the left column and find 26 ppm. Using your right hand find 1.9% of organic matter on the top of the table. Now slide your left hand to the right and your right hand down. When you fingers meet that is your recommendation to the producer for how many pounds by acre of nitrogen to put on his/her crop of corn.
You are correct the answer is 85 lbs/acre of nitrogen.
Show powerpoint slide #5
What is the next macronutrient we can recommend? Yes, phosphorous is the next one. What givens do we need here? You are right, we only need phosphorous ppm. Again follow the chart using the ppm of phosphorous in the soil sample we did the other day. Knowing that, the answer is ______________?
You can use these numbers or give sample test results.
Show powerpoint slide #6
Our last macronutrient was potassium. Again follow the chart using the ppm of phosphorous in the soil sample we did the other day. Knowing that the answer is ______________?
Show powerpoint slide #7
We are now going to look at just a couple of micronutrient recommends for our soil sample. We did not have the ability to test for these so I will give you some realistic sample numbers.
When looking at the zinc chart, we must identify our crop, our test results, and if we are irrigating the crop or not. Study this table and then raise your hand if you can tell me how much we should recommend for our irrigated corn with a soil test of 1.4% zinc. The answer is 5 lbs per acre of zinc needs added to the soil to make an optimum crop.
Show powerpoint slide #8
Explain to the students that most crops in Colorado do not need iron due to the pH nature of Colorado Soils.
Show powerpoint slide #9
Earlier we talked about salinity and soluble salt levels in soils. At this table we start with a number and recognize if the level is low, moderate, or high based on a particular crop.
Pick a couple of crops and levels to show the students the varying levels of tolerance to salts.
Objective 2--Be able to complete the fertilizer recommendation part of the Colorado Land Classification CDE.
Lead a discussion about the Land Judging CDE and how the fertilizer recommendations are another component to the CDE. Now that they know how to make fertilizer recommendations, they can apply it to a competitive situation with the CDE.
You all are so good at understanding these fertilizer recommendations. Now you are ready to complete this section of the Land Judging CDE-Agricultural Interpretations Section. This is what the score card looks like.
Show PowerPoint slide #10
Review/Summary.
Let’s concentrate on the fertilizer recommendations part of the score card. Think back to when we looked at the charts before, who can recall what are some pieces of information we might need from the contest people before we can start? Good job, _________lets hear a whoop, whoop for _________. We need a crop, organic matter and a soil test in parts per million for N-P-K, Zn, and Iron.
Students now need a copy of the Land Judging in Colorado Manual or at least the fertilizer tables and one copy of the score card.
We have gone over these tables many times so therefore you should be able to complete this assignment. Using the following givens (make up your own) fill out the score card recommendation for N-P-K-Zn-Fe and Soluble Salts.
Show PowerPoint slide #11, answers are on #12—This is the assessment.
Application
Extended classroom activity:
Have the students build bar charts to compare different crops needs. Use the same soil sample for 3-4 crops. Students will then understand how different crops have different needs.
FFA activity:
Students will be more comfortable participating in the Land Classification CDE
SAE activity:
Student can take their soil sample from their own home/farmstead and determine how much fertilizer would have to be applied to raise a particular crop at their SAE/homesite.
Evaluation.
The worksheet used for objective 2 will serve as the evaluation piece.
Answers to evaluation. Also found on Powerpoint Slide #12
115 lbs/A of N03-N
50 lbs/A of P2O5
0 lbs/A of K2O
10 lbs/A of Zn
0 lbs/A of Fe
Moderate level of Soluble Salts
Lesson Title: Fertilizer Lab
Colorado Agricultural Education Standards:
Colorado Science Standards:
Student Learning Objectives (Enablers)
As a result of this lesson, the student will:
1. Complete Nitrogen Fertilizer adjustments given an expected yield and a expected crop.
2. Be able to use percentages, fractions, addition and subtraction to make nitrogen adjustments and use a four function calculator to reinforce mathematics in a scientific and agricultural application.
Time: Instruction time for this lesson: 50 minutes.
Resources:
Land Judging in Colorado. Colorado State University, Dept. of Soil and
Crop Sciences, Ft. Collins, CO 2004.
Tools, Equipment, and Supplies
Writing surface
Writing materials
Color overheads/Overhead projector/Computer with Powerpoint and projector
Calculators for each student
Strategies for Great Teaching, Derner and Reardon
Key Terms. The following terms are presented in this lesson and appear in bold italics:
Yield, adjustment, fractions
Interest Approach
Bring in a bag of feed and display it in front of the class. As students come in they might ask what it is or why you have it. You will begin a short discussion about feed conversion.
Raise your hands if you think you have answer to this question. If I fed this 50lb bag of feed to a growing steer would he gain 50 lbs? No he wouldn’t why not? You are right, not all of the feed is converted to weight, some is for maintenance and some isn’t used. A steer might gain 7-9 lbs by eating this entire bag. What about a chicken, if he could eat all of this feed and gain an unlimited about of weight what would he weigh? He might weigh closer to 40 lbs. Why is that? A chicken is a much more efficient animal. So you see we put in an amount and only expect a fraction of that amount back of gain. This is the same case for plants and nitrogen usage.
Summary of Content and Teaching Strategies
Objective 1. Complete Nitrogen Fertilizer adjustments given an expected yield and an expected crop.
In our example the steer converted about 7 lbs of grain to 1 lb of gain and a chicken converted about 1-2 lbs of grain to 1 lb of gain. Today we are going to look at some different crops and what their conversion rates are for nitrogen. If we know how much yield we want in the end we can use it to determine how much nitrogen to put on. Earlier we went through recommendations solely based on organic matter content and soil test. Now we are going to add an additional element to it and that is an expected yield. We can do this for several crops but since we are familiar with corn tables we are going to start there.
Next slide
The students need to have a writing surface and proper writing materials.
We have seen this table before, but now can one of you read the notes at the bottom of the table out loud for the class. The rest of you follow along. (Allow them to read notes.) Good job_______, thanks for reading that. What does that mean to you? Lets focus on irrigated corn and not silage for now. The notes say we add or subtract 40 lbs of Nitrogen for every 25 bushel yield goal different from 150 bushels. So our steer was 7 to 1 and now our corn conversion is 40 to 25. Let’s break this down so we understand it.
Pass out a copy of the worksheet titled “Fertilizer Worksheet for Irrigated Corn, sorghum, and sudan for grain.” Next slide
____________What does the first line say? Let’s use our example from yesterday. We have an organic matter of 1.9%, Soil test of 26 ppm for corn. So on our worksheet we write down 1.9% for our organic matter. Step 2 asks for the Nitrogen PPM and that is what? You are so good, 26 ppm is correct for step 2. Step three asks us to find the initial recommendation and that was what? 85 lbs of nitrogen is the correct answer. Step four asks for a yield goal. This has to be given to you so I am going to use a yield goal of 175 bushels. So when we subtract 175-150 we get 25 for step four. Now take the next couple of minutes and follow the directions for steps 5 through 8 and when you get an answer for step 8 please let me know by resting your head on the desk.