exam 1

First examination 1999

Night Class

(9)1. Comment on the following factors as components of soil fertility.

a. Soil chemistry _________________________________________________________________________

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b. Soil physics ___________________________________________________________________________

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c. Soil biology ___________________________________________________________________________

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(9)2. List three criteria that are required for a chemical element to be a plant nutrient.

a. _____________________________________________________________________________________

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b.______________________________________________________________________________________

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c.______________________________________________________________________________________

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(8)3. Define the term "mineralization of a nutrient". ____________________________________________

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What is the importance of mineralization to an organic farmer? ____________________________________

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(6)4. Comment on organic fertilizers with respect to the following characteristics.

a. Concentration of nutrients ________________________________________________________________

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b. Solubility of nutrients ___________________________________________________________________

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c. Availability of nutrients __________________________________________________________________

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(6)5. Identify the following terms by definition.

a. Grade of fertilizer (analysis)_______________________________________________________________

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b. Nutrient ion ___________________________________________________________________________

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(6)6. Comment on the truth of the following statements.

a. Once upon a time all farmers were organic farmers. ____________________________________________

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b. All naturally occurring substances (rocks, minerals, plant-derived or animal-derived products) are universally identified as being organic fertilizers.

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(6)7. Describe the effect of nitrogen fertilization of crops on the following plant responses.

a. Rate of maturation of crops ___________________________________________________________

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b. Strength of plant stems _______________________________________________________________

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c. Protein concentrations in cells _________________________________________________________

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(6) 8. What are some general characteristics of crops that have a high requirement for nitrogen fertilization? (List two characteristics.)

a.__________________________________________________________________________________

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b.__________________________________________________________________________________

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(6) 9. Describe the symptoms of nitrogen deficiency on a crop which has exhausted the supply of nitrogen from the soil during a growing season.

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(6) 10. If a crop is showing symptoms of nitrogen deficiency before reaching maturity, what characteristics should a nitrogen fertilizer have for supplying nutrition to the crop in the current growing season?

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List two fertilizers that one could use. (a) _______________________ (b)________________________

(6). 11. Explain why only about half of the nitrogen added to soil as a fertilizer is recovered by crops. (Describe a process by which N is lost or describe a condition that causes plants not to recover the N).

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List a practice that a farmer might use to increase efficiency of nitrogen usage by crops, that is to lessen losses or to increase recovery.

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(6) 12. Identify the following terms by definition.

a. Humification _______________________________________________________________________

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b. Nitrogen immobilization ______________________________________________________________

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c. Nitrogen leaching ___________________________________________________________________

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(8) 13. Define how one would maximize the availability of phosphorus in rock phosphate by listing the conditions mandatory for the use of rock phosphate as a fertilizer.

a. _____________________________________________________________________________________

b. _____________________________________________________________________________________

c. _____________________________________________________________________________________

d. _____________________________________________________________________________________

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(6) 14. Define the following terms:

a. Superphosphate________________________________________________________________________

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b. Phosphorus fixation _____________________________________________________________________

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c. Colloidal rock phosphate _________________________________________________________________

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(6) 15. Comment on the value of the following materials as phosphorus 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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