PLSOIL 120 Second Examination

Night Class

(6) 1. Describe the symptoms of advanced potassium deficiency in the following plant organs:

a. Seeds or fruits _________________________________________________________________________

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b. Leaves _______________________________________________________________________________

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c. Stems ________________________________________________________________________________

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(12) 2.What is the meaning of the following terms used to describe the presence of potassium in soils

a. Primary mineral K ______________________________________________________________________

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b. Nonexchangeable K ____________________________________________________________________

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c Exchangeable K ________________________________________________________________________

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d. Soil solution K _________________________________________________________________________

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(6)3. Comment on the value of the following materials as potassium fertilizers:

a. Animal residues or by-products ____________________________________________________________

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b. Plant residues or by-products _____________________________________________________________

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c. Naturally occurring rocks and minerals ______________________________________________________

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(9) 4. What is a function of calcium in plants with regards to cell expansion or growth?

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What is meant by the expression that "Calcium is immobile in plants"?_________________________________

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How does the immobility of calcium in plants affect the expression of symptoms of calcium deficiency?

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(6)5. Comment on the value of the following materials as fertilizers for provision of calcium in organic farming.

Phosphate fertilizers _________________________________________________________________________

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Farm manures______________________________________________________________________________

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Fruit by-products ______________ _____________________________________________________________

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(4) 6. List a production problem that is associated with calciuim deficiency in the following crops.

Apples _____________________________ Tomatoes _______________________________

Carrots _____________________________ Lettuce (cabbage) _________________________

(9) 7. List three functions of magnesium in plants.

a. ________________________________________________________________________________________

b.________________________________________________________________________________________

c.________________________________________________________________________________________

(6) 8. Comment on the value of the following materials as fertilizers for magnesium-nutrition of crops.

Agricultural limestones_______________________________________________________________________

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Epsom salts _______________________________________________________________________________

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Talc or soapstone ___________________________________________________________________________

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(8)9. Comment on the value of the sulfate of potash magnesia as a fertilizer for use in organic farming.

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(4)10. Why is the potential of sulfur-deficient crops of much greater concern to the farmer who uses modern chemical fertililizers than to the organic farmer?

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(3)11. List three conditions that might occur in soils to induce micronutrient deficiencies in crops.

a. ________________________________________________________________________________________

b.________________________________________________________________________________________

c.________________________________________________________________________________________

(6)12. List three factors of soil acidity that contribute to the condition known as "Acid-Soil Infertility".

a.________________________________________________________________________________________

b.________________________________________________________________________________________

c.________________________________________________________________________________________

(4)13. For one of the factors listed in Question 12, describe how this factor contributes to acid-soil infertility.

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(8)14. Comment on the value of each of the following materials as limes to correct the nutritional difficulties that occur with plants growing in acid soils.

a. Calcite (CaCO3)__________________________________________________________________________

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b. Dolomite________________________________________________________________________________

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c. Quicklime_______________________________________________________________________________

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d. Wood ashes______________________________________________________________________________

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(4)15. Define these terms.

a. Active soil acidity _________________________________________________________________________

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b. Reserve soil acidity _______________________________________________________________________

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(4) 16. Why is the lime requirement to raise a sandy clay loam from pH 5.5 to pH 6.5 larger than that required to raise the pH of a sandy loam from pH 5.5 to pH 6.5.

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(6)17. Describe a process through which each of the following activities lead to soil acidification.

a. Leaching ________________________________________________________________________________

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b. Additions of organic matter to soil ___________________________________________________________

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c. Microbial activity _________________________________________________________________________

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(4)18. Evaluate the following practices of utilization of limestone on land.

a. Application of limestone to the surface of land then plowing the limestone into the soil with a moldboard plow.

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b. Selection of coarse limestones (10 to 25-mesh) to lessen the frequency of limestone applications.

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