Colorado Agriscience Curriculum Section: Plant & Soil Science Unit: Unit 7: Soil Management Lesson Title Lesson 1: Introduction to Soil Fertility and pH with Soil Sampling Lab Ag Ed Standards: Standard AGII 10.9 The student will demonstrate an understanding of soil fertility and its effect on crop production. Enabler 10.9.7 Understand soil pH’s effect on fertility and land use. Colorado Science Standards: Standard SCI: 2.0 Physical Science: Students know and understand common properties, forms, and changes in matter and energy. (Focus: Physics and Chemistry) Competency SCI 2.12 Describe and explain properties and composition of samples of matter. Student Learning Objectives (Enablers) As a result of this lesson, the student will: 1. Explain what the common macronutrients found in soil are. 2. Understand what fertilizers are and why they are used. 3. Calculate how much available fertilizer is found in a bag of fertilizer. Time: Instruction time for this lesson: 50 minutes for lesson 50 minutes for lab Resources: Biondo, Ronald J. & Jasper S. Lee. Introduction to Plant and Soil Science and Technology. Interstate Publishers, Inc. Danville, IL 1997. Tools, Equipment, and Supplies 1 Set of 3 Soil Samples per group Writing surface Writing materials Color overheads/Overhead projector/Computer with Powerpoint and projector Bag of fertilizer Calculator Key Terms. The following terms are presented in this lesson and appear in bold italics: Nitrogen, Phosphorous, Potassium, Availability Interest Approach Acquire three different soil samples ahead of time and separate into jars. You will need 1 set of 3 jars per group. You will be asked to look at the samples, feel them, smell them, etc., and make a list of what is in the soil samples and also to pick which sample is the “healthiest” looking. Each group report their findings. Today, we are going to take a closer look at something we often take for granted-soil. When I say “DIAGNOSE,” please form groups of 4 and send 1 individual to the front of the classroom to get 3 jars that have different soil samples in them. Each group needs to pick a secretary to record the group’s findings. You will have 5 minutes to complete this exercise. Your task is to develop a list of all the things that could be in your sample. Touch, smell, and visually inspect the sample and pick which one is the “healthiest.” You will report your findings to the class. Questions? Ready “DIAGNOSE.” Give a warning signal at 1 minute. At the 5 minute mark, call time and ask each group to report their findings and selection of the healthiest sample. Give encouragement to each group then ask them to return to their seats and prepare to take notes. As you can see there is quite a list of items that can be found in soil: dead plants, organisms, water, but there are some things that we can’t see. What might be in your sample that we can’t see? Lead discussion to nutrients. That’s right, the fact that nutrients are critical to plant growth is where we are headed! Summary of Content and Teaching Strategies Objective 1. Explain what the common macronutrients found in soil are. Can any of you tell me who are the 3 most popular professional baseball teams are? Take a few responses. Even though there are many professional baseball teams, there are a handful of popular ones. Just like professional baseball there are many nutrients found in the soil, but there are three that are the most popular and have the greatest effect on plant health. Can anyone name some of them? They are listed on the periodic table of elements. Give hints if necessary. Then show Powerpoint Slide #2 and ask students to capture the following information in their notes. The most popular macronutrients found in soil are Nitrogen (N), Phosphorus (P), and Potassium (K) These are always listed in this order on labels and referred to as NPK. What do each of these elements do in the soil for the plant? Show powerpoint slide as you discuss each. Slide #3 Nitrogen is the most popular macronutrient. It give a plant it’s green color, assists with rapid growth and vigor, promotes seed and fruit development and increases protein and yield. Slide #4 Phosphorus aids seedlings to germinate, very important in the early stages of the crop, and stimulates root growth. Slide #5 Potassium is responsible for production of carbohydrates in the plant, produces plumper seeds, and acts as the water valve for letter water in and out of the plant. Use the Heiroglyphics Moment and have the students draw a picture next to each element to help them remember the function of each nutrient. Ask a few to share their pictures. Objective 2. Understand what fertilizers are and why they are used. Will someone please share with the class why you think that your coaches ask you to practice everyday for a sport? Take responses. You are right, to make you better. What can we do with soil to make it better? Practice isn't it, but fertilizer is, you are correct!! We know fertilizers make plants grow but how does it make the soil better? Show slide #6 Fertilizers help plants get the nutrients they need by adding deficient materials to the soil. It makes nutrients more available to the plant to get what it needs. What ways can we find out how much nutrients are in the soil? Take responses. Then review slides 7 and 8. Show slide #7 1) Visual inspection--looking at the plants--not very accurate 2) Tissue testing--take a tissue sample of the plant and have it analyzed--very accurate but expensive and not widely used 3) take a soil sample--accurate and relatively inexpensive, home kits are available, can be sent to labs. In what forms would we find fertilizers? Show slide #8 Fertilizers come in many forms--dry (granules), liquid (usually diluted with water) gas (anhydrous ammonia) solids (manure), spikes (concentrated quantities placed in ground and allowed to dissipate through soil). Hold up an empty bag of fertilizer. Here is a bag of fertilizer, what might you want to know about this fertilizer? Take responses and guide discussion towards reading the label and following the label. What do these three numbers down on the bottom mean? These numbers represent the percent of NPK in this bag. (CHANGE IF SAMPLE BAG IS DIFFERENT OR USE THE POWERPOINT SLIDE #9. The numbers were 20-15-10. That means there is 20% nitrogen, 15% phosphorus, and 10% Potassium in the bag. The rest of the bag is inert products or carriers. Take responses leading to (Change if sample bag is different or use the Powerpoint Slide #9.) Quickly use the Eyewitness News Moment with two volunteers to report the breaking news about what N, P, and K stand for. Have them switch roles and report again for the class on how to read the numbers and what they stand for. Objective 3. Calculate how much available fertilizer is found in a bag of fertilizer. Showing the bag again, guide the students through the following questions. We said that our bag had 20-15-10 on it and there is 20% nitrogen, 15% phosphorus, and 10% Potassium in the bag, but how many pounds are there of each in the bag? Show slide #10 Assume the bag is 100 pounds, 1) 20% Nitrogen means there is 20 pounds of Nitrogen, 2) Multiply the 15% Phosphorus in the form of P2O5 X .44=6.6 lbs 3) Multiply the 10% Potassium in the form of K2O x .83= 8.3 lbs 4) If the bag is less than 100 pounds you would multiply the answers above X the fraction of the bag to 100. (Example-for a fifty pound bag, 8.3 X 50/100) Finish up with the following problems. They are also on slide #11 with answers on slide #12. A 50# bag of 10-10-10 #N #P #K A 50 # bag of 10-20-15 #N #P #K A 100# bag of 20-10-0 #N #P #K Review/Summary. Use the Picasso Moment to have the students draw in their notes 3 main concepts they now understand about soil fertility. (Allow time to share two or three students’ ideas.) Now we have covered Soil Fertility, all of you did a great job. We still don't know which sample is the "healthiest" but tomorrow we will find out!! This leads into the pH lab. Application Extended classroom activity: Students could contact a local Crop Consultant or fertilizer salesman to set a meeting to interview then on fertilizers and how they are most commonly applied in your area. FFA activity: Invite a crop consultant to present at a chapter meeting on concerns in soil nutrition. SAE activity: Encourage students to write a one page essay on the effect of soil nutrition on their SAE. Evaluation. Name_______________________________________________DATE_____________ Circle the best answer for each question. 1. The three most common macronutrients in the soil are expressed as: A. N-K-P B. N-P-K C. P-K-N D. C-P-R 2. Nitrogen in the soil aids the plant by: A. Allowing water in and out of the plant B. Stimulate root growth C. Give the plant its green color D. Produce carbohydrates 3. Phosphorous is important in what stage of growth? A. Seed germination B. Plant propagation C. Cell division D. Fertilization 4. Potassium regulates what element into the plant? A. Other elements B. Sunlight C. Food D. Water 5. What form of testing is the most accurate, but most expensive? A. Visual Inspection B. Tissue Cultures C. Soil Analysis D. Microscopic Cellular Analysis 6. What is the most economical and efficient form of testing to determine macronutrient levels? 7. List three different forms or sources of fertilizer. 8. If a bag of fertilizer reads 20-35-15 what percent of the mix is potassium? 9. Assuming the bag is 50 lbs. how many pounds of nitrogen are in the bag? Answers to Assessment: Name_______________________________________________DATE_____________ Circle the best answer for each question. 1. The three most common macronutrients in the soil are expressed as: a. N-K-P b. N-P-K c. P-K-N d. C-P-R 2. Nitrogen in the soil aids the plant by: a. Allowing water in and out of the plant b. Stimulate root growth c. Give the plant its green color d. Produce carbohydrates 3. Phosphorous is important in what stage of growth? a. Seed germination b. Plant propagation c. Cell division d. Fertilization 4. Potassium regulates what element into the plant? a. Other elements b. Sunlight c. Food d. Water 5. What form of testing is the most accurate, but most expensive? a. Visual Inspection b. Tissue Cultures c. Soil Analysis d. Microscopic Cellular Analysis 6. What is the most economical and efficient form of testing to determine macronutrient levels? Soil testing 7. List three different forms or sources of fertilizer. Dry, gas, liquid, spike 8. If a bag of fertilizer reads 20-35-15 what percent of the mix is potassium? 15% 9. Assuming the bag is 50 lbs. how many pounds of nitrogen are in the bag? 20%x.5=10 lbs. Colorado Agriscience Curriculum Section: Plant & Soil Science Unit: Soil Management Lesson Number: PS U7L1---Lab Student Learning Objectives (Enablers) As a result of this lesson, the student will: 1. Take a soil sample and prepare it for testing 2. Understand soil pH Time: Instruction time for this lesson: 50 minutes. Resources: Colorado State University Cooperative Extension Fact Sheet, no. 0.500,Soil Sampling, J.R. Self and P.N. Soltanpour http://www.ext.colostate.edu/pubs/crops/00500.html Tools, Equipment, and Supplies Soil probe, auger, or spade (enough for 3-4 groups to work at one time) Plastic buckets or sacks for samples (1 per student) Surface for working with soil Baby food jars or something to mix soil and water together Measuring cups Distilled water 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: Sample area, pH, Consistency Interest Approach Create manageable work groups based on your class numbers and their ability. Instruct students that we are going to go out and take a soil sample. Show them how to use the soil probe or auger. Inform them that for the purposes of this lesson you will be assuming you are testing soil for a farm crop and that testing should be performed to the depth of the tillage. Try to sample at the 6-8 inch depth. They should try to get samples from different areas around the school. They should avoid compost areas, under the drip lines of trees, and the areas close to driveways or streets. After they get their sample it should be put into the plastic bucket or sacks. Plastic works best because other materials like galvanized buckets can skew the test results. Also have the student use latex gloves if possible. It aids in clean up and keeps the sample integrity intact. Today we need to go take some soil samples so we can test them tomorrow. We are going to work in groups for this exercise. We are going to use a soil probe and take samples to the depth of 8 inches. Push the probe in the ground like this and then pull it back out of the ground. You need to wear gloves and then place the sample in the Ziploc bag provided. You will need to write your name on it. Spread out, pick an area to sample, note the location in your notes, take your sample and return to the classroom. You will have 10 minutes. Summary of Content and Teaching Strategies Objective 1. Take a soil sample and prepare it for testing. The samples must be crumbled up, debris removed, and spread out to air dry. Remind the students to keep their gloves on during this process. Now that we have our samples we must prepare this sample to be analyzed. When I say “Crumble” I want you to take your samples, lay them out on the table in front of you, crumble them up, remove any debris, and spread it out so it can air dry. You have 2 minutes to do this, “CRUMBLE” Give a warning and then at time call students back to the work area and instruct them to get be prepared to take notes. We now will let the samples dry out a little bit. When taking samples for field testing it is a little more involved then what we have done. The testing we will do will be fairly simple and would be classified as home use. If we were producers on a larger scale we would take our samples according to the lab specifications and send our sample off for extensive testing. We are going to let the sample dry for a little bit and then prepare it for testing we will perform tomorrow. Great job following directions and getting your samples ready. Objective 2. Understand soil pH. You will now need to be prepared to use transparencies or a projector. Begin a discussion about pH and making sure students understand the scale. Ask for a volunteer to come forward to do a little taste testing. In very small quantities ask the student to take a sample of baking soda, distilled water, and lemon juice. After the initial “yuck” reaction of the soda and the lemon juice ask them to tell you how they tasted. Guide the discussion to reveal baking soda has a bitter taste while lemon juice has a sour taste. Then reward the participant with something good to eat like a pop, or candy bar. While our samples are drying we are going to cover one more area that we will be testing for. First an experiment, I need a volunteer to do some taste testing for me. I have three items up here. Here is the first sample (baking soda), wash it out with some water and then the third sample (lemon juice), what did you notice about the differences…………..You are right the soda was bitter and the juice was sour? Why is that? What is a scale we could measure sour to bitter on? How many of you have heard of pH? Show PowerPoint slide # 13 PH is the scale we use to measure acidity (sour) to basic (bitter). What is the range of ph? You are right the range is 0-14. Who can remember which side of the scale is basic and acidic? Show PowerPoint slide #14 The acid side starts with zero, just like “A” starts the alphabet, 7 is a neutral item, like distilled water, and 14 end the basic side. “A” come before “B” so always remember an acid starts the scale and bases end the scale. Now that we remember what pH means and why it is important for soil, let’s add a Karaoke Moment. Show PowerPoint slide #15 pH is the measure of how an item reacts with water. If it gives off hydrogen ions (H+) it is an acid. An example would be hydrochloric acid. When it meets water it forms hydrogen ions and chloride ions. On the other hand a base give off hydroxide ions when reacting with water. (Add a Motion Moment.) Sodium hydroxide is a base because it forms sodium ions and hydroxide ions when mixed with water. So why is this important for soil? Show PowerPoint slide #16 Knowing the pH of our soil is important for two reasons: It allows us to figure what changes we might need to make the soil more efficient for the crop we are to be growing and It also determines nutrient availability (some nutrients become unavailable to plants at low or high pH levels) So we need to know our pH and the crop we want to grow and make sure that the two will match and work together and not against each other. You now need to go back to your samples and prepare them for testing. We need to go back to our samples and finish preparing them for testing. Ideally we would have our samples completely dry before we sent them off for testing. Our home use kits allow the sample to be used since we are going to add water back to them. We do need to make sure that the sample is free of debris. Take your sample and divide it in half. Set one half to the side to be used tomorrow undisturbed this portion will be used for pH testing. The other half will be used for N-P-K testing. Any form of measurement can be used but a 5:1 ratio is important. Use whatever works given the size of the sample and your jars. We need to be precise here. Take this measuring cup and add 5 parts distilled water and 1 part soil and put it in the jars provided. Now thoroughly shake your sample for at least one minute. Then put your jars down and do not disturb them. We want to give ample time for the soil to settle and we will test tomorrow. Review/Summary. Review by leading the class in the best Karaoke Moment and Motion Moment for review. Application Extended classroom activity: Invite a Extension agent to come in and talk about soil samples and how they are now using GPS to grid fields and take samples for variable rate application technology. FFA activity: Use LK lesson HS #21 to reinforce that wrong/right pH of soils negatively/positively affects the production, just as wrong/right influences negatively/positively affects students productivity and success in life. SAE activity: Encourage students to go home and take a soil sample out of the front yard, dry it out, add 5 parts of water to 1 part soil and bring it in for testing the next day if time allows.
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