l. Explain why the C/N ratio of organic matter normally narrows with composting.
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What is the main advantage of narrowing the C/N ratio through composting of organic matter?
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What are the major losses or disadvantages in composting?
a. _________________________________________________
b. _________________________________________________
c. _________________________________________________
2. What is the principal purpose of incorporating a green manure into a crop rotation?
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What are two secondary or special benefits (other than that listed above) received from a green manure crop?
a. ________________________________________________
b. ________________________________________________
What characteristics of a crop should one select in choosing a good green manure crop?
a. __________________________________________________
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b. __________________________________________________
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c. __________________________________________________
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How does one determine when to turn the green manure crop into the soil?
a. _________________________________________________
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b. _________________________________________________
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3. What are the differences in root distribution between a mulched and an unmulched crop?
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Relate the differences to the management of mulches. _____________________________________________________
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4. List four mulching materials and a function of each one.
a.___________________________________________________
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b.____________________________________________________
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c.____________________________________________________
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d.___________________________________________________
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5. Circle the plant nutrients among this group of elements.
copper nitrogen iron
zinc potassium sulfur
magnesium sodium cobalt
strontium calcium phosphorus
fluorine boron neon
chlorine molybdenum cesium
bromine vanadium rubidium
manganese aluminium selenium
6. Comment on the truth of the following statements.
a. The kind of nutrients used by plants is the same whether the nutrients are supplied organically or by conventional means.
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b. Nitrogen fertilization is included normally in any program of soil management.
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c. Organic farmers run deficits in their programs for phosphorus and potassium fertilization.
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6. Explain the meaning of the following terms.
a. 5 - 10 - 10 grade of fertilizer_________________________________
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b. Nutrient deficiency symptom__________________________
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c. Availability of nutrients in soil____________________
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d. Nutrient immobilization______________________________
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e. Crop lodging_________________________________________
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7. Why is only about 3 to 20% of the phosphorus in chemical fertilizers available to a crop during the first season after the application of the fertilizer?
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Why is it not advisable to use rock phosphate if the pH of the soil is above 5.5?
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List two chemical processes through which the addition of organic matter increases the availability of phosphorus in the soil.
a._______________________________________________________
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b._______________________________________________________
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8. What features distinguish an organic fertilizer from a conventional chemical fertilizer?
a.______________________________________________________
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b.______________________________________________________
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9. Evaluate the following materials as organic fertilizers.
a. Plant materials______________________________________
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b. Animal tissues_______________________________________
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c. Natural rock materials_______________________________
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d. Waste materials______________________________________
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10. Comment on the effectiveness of following practices of plant disease control.
a. Selection of disease-resistant plant varieties ________________________________________
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b. Control of weeds and insects in immediate vicinity of a vegetable garden ______________
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c. Provision of good drainage conditions in the soils of a flower garden _________________
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d. Whitewashing the trunks of apple trees ___ ________________________________________
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