Week 4_Soil Chemical Properties_Dialogue-2

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Hort Science_AGOR 1 Soil Chemical Properties Dialogue Name: Instructions Review and preview the original format of this document in the Canvas module. The original numbering and charts need to stay in place. Do not delete anything from this document. Add in your short answer responses and highlight/bold multiple choice. Highlight or bold all text inputted into this document. Answer all questions and fill in all definitions. Save this document in a folder on your PC, so you have them for reference. When submitting the worksheet  Word Documents or PDF file format only  You may type/edit your responses and save them as Word or PDF  You may print out this document, clearly write in the answers, scan it, and save it as a PDF. After submitting, check your upload to be sure you have submitted the correct file. Grading Score Criteria 20/20 points All answers are complete and accurate with appropriate grammar. 15/20 points Missing/incorrect on 1-2 questions/definitions, or incomplete sentence(s), or modifying the format of this document in numbering or highlighting or bolding. (Complete sentences include capital letters, subject, predicate, and a period. Do not forget basic grammar, including capitalizing "I" when typing in the first person) 0-10/20 points Missing/incorrect on 5 more questions/definitions, or incomplete sentence(s), or modifying the format of this document in numbering or highlighting or bolding. 0 points Late, no submission, or or the wrong file uploaded

Hort Science_AGOR 1 Soil Chemical Properties Dialogue Name: Term Definition CEC A measure of soil's ability to retain fertility (cationic forms of plant-essential elements); the sum of exchange able cations absorbed by a soil, expressed in milliequivalents per 100 g of soil equivalent to the milligrams of H+ that will combine with 100 g of dry soil Saline soil A soil containing sufficient soluble salts to impair plant growth and development. Sodic soil A soil that contains sufficient sodium to adversely affect its physical properties and water infiltration; a soil with an exchangeable sodium percentage greater than or equal to 15% Soil pH Describes the relative acidity or alkalinity of a solution. Base Cation Saturation Ratio (Use the lecture for this one) Generally move the ph closer to neutral and alkaline/ basic (in order) Ca,Mg,K,Na Vocabulary 1. This is the fourth time around doing vocabulary. You probably have the hang of it now. This is a short but mighty vocab list! a. None of your lists are short. b. Short and mighty, like Mighty Mouse? (google this, I am probably a little older than you…)

Hort Science_AGOR 1 Soil Chemical Properties Dialogue Name: The Text! Let’s Talk 2. Cation Exchange Capacity (CEC) is a fancy, fancy term. I never need to use it unless I am reading a soil report. If a soil has a low CEC, it’s most likely a sandy soil. If a soil has a high CEC, it is probably a clay soil or very high in organic matter. Read the Cation Exchange Capacity section on page 44, and you will find this sentence below. Fill in the blanks. When cation exchange occurs, the ____ cation____ released from the ____ clay mineral ___ into the soil solution becomes available for absorption by plant roots. 3. Read the Cation Exchange Capacity section on page 44 again. You don’t have to but it’s a good suggestion… Which of the following statements is false regarding CEC? a. CEC measures the amount of cations that can be adsorbed or held by a soil b. It is measured in units of milliequivalents per 100 grams of soil c. Mineral soils with a higher cation exchange capacity are usually more fertile than those with a lower exchange capacity because the former more effectively resist the loss of the plant nutrient cations through the leaching process. d. Clay particles attract negatively charged plant nutrient ions, such as nitrate and sulfate. e. The amount and kind of clay in soils are critical factors in plant growth because of the clay’s capacity to adsorb cations is important in plant nutrition. 4. Read the Cation Exchange Capacity section on page 44: Clay minerals have a low affinity for water. a. True b. False 5. Read the Cation Exchange Capacity section on page 44, you know, for the fourth time. You’ll want to find each of the sentences below within the text and identify the false statement. Which of the following statements is false? a. The negative charges on the clay minerals attract the positive charges on the hydrogen(H+) ions in water(H2O). b. Montmorillonite clay, commonly found in CA, swells greatly when wetted and shrinks when dry, leaving wide cracks. c. An intermediate amount of clay in a soil (loamy texture) improves its capacity to hold water and plant nutrient ions because of the negative charges on clay minerals’ surfaces and the large surface area associated with clay particles. d. A clay soil has almost 100,000 times more surface area than a soil of fine sand grains of the same weight e. As soil particles become smaller and smaller (from gravel to sand to silt to clay), the soil has more surfaces available for chemical reactions to occur f. All of the above statements are TRUE

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Hort Science_AGOR 1 Soil Chemical Properties Dialogue Name: 6. Read the Soil pH section on page 48. Fill in the blanks: The term pH describes the relative _ acitidy______ or ______ alkalinity ________ of a solution. 7. So, you’re hip to the acid and alkaline as a reference to the pH scale. Again, have a read of the pH section. This stuff will come in handy for the rest of your horticulture journey. The pH is the relative concentration of hydroxyl (OH) ions in the soil. a. True b. False 8. For me, this question was challenging as a concept. How could one number on the scale be so much more powerful that the next!? Well the text will tell you. And they do a much better job than me. A pH of 5.0 is 10 times more acidic than a pH of 6.0. a. True b. False 9. Why all the talk about pH? Because pH affects the availability of nutrients in the soil. If your pH is too high, several nutrients not available. If you pH is too low, several nutrients not available. There is an ideal range for soil pH! Read the Soil pH section on page 48. Most crops do best when the pH of the soil is slightly acidic to neutral (5.5-7.5) a. True b. False

Hort Science_AGOR 1 Soil Chemical Properties Dialogue Name: 10. Watch the audio lecture closely for to help with this question. The pie chart image below represents the ions that occupy exchange sites on soil particles. Use complete sentences to describe which ions and their percentages are represented on the pie chart. Start with the large blue section on the right/left side of the pie chart, then the second largest red section, then the small green section, and then the smallest purple section. You may remove the circles covering the names of the ions. Remember, complete sentences here. The largest blue part is calcium with a content of 60-70%, the red part is magnesium with a content of 10-20%, the green part is potassium with a content of 2-5%, and the purple part is sodium with a content of 0.5-3%. , the last light blue part is hydrogen, the content is 12%. , if the three main elements are dominant in the soil, the soil is healthy. 11. So if you could customize every soil particle to have the most beneficial ions attached to it, you would use the cations above, and it is very important to remember that you would use them in that ratio. These ions are all Base Cations. Hence the term Base Cation Saturation Ratio. When correcting soil chemical issues, we are generally trying to restore balance to look like the above image. a. I read your note here and it kind of makes sense. b. I read your note here and it makes no sense c. I read your note here and it is much clearer now d. I don’t like cats or cations 12. Do not ignore the Base Cation Saturation Ratio in the definitions at the beginning of this worksheet. The two questions above this address it directly. a. I understand I should fill in the BCSR definition in the vocab section b. I am not going to fill in the BCSR definition and it will count as a missed/incorrect question

Hort Science_AGOR 1 Soil Chemical Properties Dialogue Name: 13. The image below is a good visual of the pH scale. Watch the lecture, read the text and use the above question for help on this. Use complete sentences to describe where the sweet spot for plants lies on this scale. Most crops grow best when the pH is slightly acidic to neutral, as the mineral nutrients necessary for plant growth are extracted from the soil. 14. Read the Effect of Soil pH section. You have to jump a few pages up to get to this section. In the second edition, which you should have, it is on page 63. The topsoil can lose calcium, magnesium, and potassium via leaching or removal by growing crops. With the loss of these particular cations, the soil can become more acidic. a. True b. False 15. Read the Soil Salts and Salinity section on page 49: Which of the following statements is false? a. Chemically speaking, a salt is the neutral product of the reaction between and acid and a base. b. Soluble salts are minerals that do not dissolve in water. c. In moist climates they are naturally washed out by rainfall, but in arid climates (like CA) they naturally accumulate as water evaporates and leaves them behind. d. Deposition of dust and precipitation, fertilizers and irrigation water all contribute to salt additions to the soil.

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Hort Science_AGOR 1 Soil Chemical Properties Dialogue Name: 16. Read the Soil Salts and Salinity section on page 49: As salts in the soil become more concentrated, it becomes more difficult for plants to take up water. a. True b. False 17. Read the Soil Salts and Salinity section on page 49 and fill in the blanks: Salt concentration in soil is measured as ______ electrical conductivity _________ in units of ____ Deci siemens per meter __________. 18. Read the Soil Salts and Salinity section on page 49. The answers are number values needed below are describe in the text. Fill in the table. You do not need compete sentences here. Symptoms EC level (number) EC level that can damage salt-sensitive plants 2.0 dS/m or greater EC level that most plants can tolerate 4.0 dS/m EC levels that may cause easily diagnosed foliar symptoms two or four times the amount 19. Read the Soil Salts and Salinity section on page 49: Use complete sentences to describe: Why are CA soils so susceptible to developing saline soils? CA Soil iis more prone to becoming saline because the process of water evaporation from the soil's surface is more common than the leaching away of water. As a result, salt, which is dissolved in the water, tends to accumulate in the root zone of the soil. 20. Read the Soil Salts and Salinity section on page 49. Use complete sentences to describe:

Hort Science_AGOR 1 Soil Chemical Properties Dialogue Name: Your text talks about in the Soil Salts and Salinity section. How does it describe “osmotic stress”? When soil contains a high level of soluble salts, it becomes challenging for plant roots to absorb water. This difficulty arises because the water molecules are strongly bound to the salt ions, making them less accessible to the plants. 21. Read the Soil Salts and Salinity section on page 49 and the lecture from class. Use complete sentences to describe: How might one get salts out of the root zone? Saline soil should be irritagted with excess water, more than is required by the plants to wash excess salts from the root zone. 22. Read the Soil Salts and Salinity section on page 49. Which of the following is False?: a. Sodic soils have a pH of 8.5 or greater b. The alkaline pH is due to an excessive accumulation of sodium(Na+) c. Excess sodium can deteriorate soil structure and results in poor water and air infiltration d. A soil cannot be both “saline” and “sodic” 23. Go back and highlight or bold your responses and vocabulary and remember to submit this as a Word Doc of PDF only. a. I have read the above statement and have/will save this document as Word or PDF and have highlighted all text input into this document b. I have not read the above and may lose points 24. Use complete sentences to describe: How has your time management been so far? My time management has been efficient, effectively balancing and addressing a wide range of queries within the given time constraints.

Week 4_Soil Chemical Properties_Dialogue-2

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