Agronomy 354 Quiz 1, January 20, Name (-5 points if not written legibly))

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1 Quiz 1, January 20, 2006 Name (-5 points if not written legibly)) Below are 7 multiple choice questions. Mark the best answer. Each correct response is worth 3 points. 1. The item below that is not a function of plant roots is a) disease suppression. b) anchorage. c) storage. d) absorption. 2. The area of the plant root where root hairs develop is the a) root cap. b) meristematic zone. c) zone of elongation. d) zone of maturation. 3. The rhizosphere is high in microbial activity because a) it is warmer than the surrounding soil. b) it contains more carbon than the surrounding soil. c) it contains more moisture that the surrounding soil. d) it is less compacted than the surrounding soil. 4. The ideal soil for crop production a) is 20% pore space and 80% solids. b) is 80% pore space and 20% soilds. c) contains water in half of the pore space when the soil is at field capacity. d) contains water in 80% of the pore space when the soil is at field capacity. 5. The Law of Diminishing Returns was proposed by a) Liebig. b) Mitscherlich. c) Bray. 6. The smallest soil particles are classified as a) sand. b) silt. c) clay. 7. What cultural practices can affect the way a plant s root system develops? a) fertilizer placement b) tillage practices c) irrigation management d) all of the above e) a and b

2 Quiz 1, January 20, 2006 Please briefly answer each of the following questions. 8. Please define soil tilth. (5 points) 9. Why is it advantageous for plants to develop root hairs? (5 points) 10. Briefly explain the difference between soil texture and soil structure. (5 points) 11. Why is development of soil structure important for good plant growth? (5 points) 12. How does infection of roots by vesicular arbuscular mychorrizae influence nutrient uptake by plants? (5 points) 13. Why are we interested in managing soil fertility? (4 points)

3 Quiz 2, February 3, 2006 Name: (-5 points if not legible) Part 1. Which nutrient is responsible for the following deficiency symptoms? (2 points each) Choose the one best answer. Each correct answer is worth 3 points. 4. The primary mineral that is a source of phosphorus is a) augite. b) apatite. c) quartz. d) orthoclase. 5. The nutrient that is not incorporated into organic molecules in plants is a) Nitrogen. b) Zinc. c) Molybdenum. d) Potassium. 6. A soil test interpretation of very high means there is a) a very low probability of a response to an addition of fertilizer. b) a very high probability of a response to an addition of fertilizer. c) a high chance of a large (bu/a) response. d) a large amount of fertilizer is required to optimize yield. 7. The procedure used to define the relationship between the amount of a nutrient extracted from a soil using laboratory procedures and the amount that can be absorbed by a plant growing in the same soil is called a) correlation. b) calibration. c) interpretation.

4 Quiz 2, February 3, The largest inherent error in soil testing is in a) the laboratory procedures. b) interpreting the results. c) taking the soil samples. d) transporting the soil samples to a laboratory. 9. The essential nutrients that are mobile in plants are a) N, P, K, Zn. b) N, K, Zn, Fe. c) P, K, Fe, Mg. d) N, P, K, Mg. Part 2. Short answer essay 10. Please list the chemically available form of the cation micronutrients copper, iron, manganese, nickel, and zinc. (5 points) 11. Briefly explain the concept of hidden hunger. (5 points) 12. Please explain the difference between a plant sap test and plant total analysis. (5 points)

5 Quiz 2, February 3, The bottom leaves of corn plants in one of your father s fields are showing chlorosis that begins at the leaf tips and proceeds down the leaf edges. What is most likely causing this? What do you tell him to do? (6 points) 14. Explain how we deal with soil variability when taking soil samples to estimate plant available P and K. (5 points)

6 Quiz 3, February 17, 2006 Name: (-5 points if not legible) Part 1. Choose the one best answer. Each question is worth 2 points. 1. As soils weather they become a) more alkaline. b) neutral in reaction. c) more fertile. d) more acid. 2. The essential nutrient that is held most tightly by the soil's cation exchange capacity is a) Aluminum. b) Potassium. c) Hydrogen. d) Calcium. 3. Negative charges on clay particles due to replacement of Si 4+ with Al 3+ in the tetrahedral layer are a) permanent. b) ph dependent. c) on the broken edges of the clay. d) not important. 4. If poh = 8, the [H + ] = a) M/L b) M/L c) g/m d) g/m 5. ph is defined as a) log [H + ]. b) -log [H + ]. c) ln [H + ]. d) -ln [H + ]. 6. The atomic weight of Potassium is 39 g/mole. What is its equivalent weight? a) 39 g/eq b) 19.5 g/eq c) 78 g/eq d) none of the above

7 Quiz 3, February 17, Why do farmers apply limestone? a) to increase the availability of P to crops. b) to decrease profit. c) to increase profit. d) to decrease the amount of soil organic matter. 8. A soil has a cation exchange capacity of 25 meq/100g and contains 9 meq Calcium/100g, 3 meq Magnesium/100g, 0.3 meq Potassium/100 g, 0.2 meq Sodium/100g, 8 meq Aluminum/100g, and 4.5 meq Hydrogen/100g. What is the percent base saturation? d) 50% e) 68% f) 82% g) 100% 9. Soil A has a cation exchange capacity of 10 meq/100g and soil B has a cation exchange capacity of 25 meq/100g. The ph of both soils is 5 and you want to lime them to a ph of 6.5. Which soil will required the greatest amount of limestone? e) Soil A f) Soil B g) They will require the same amount of limestone. 10. Most of the cations in a soil are a) in the soil solution. b) on the cation exchange. c) evenly distributed between the cation exchange and the soil solution. 11. Reserve acidity is estimated by measuring a) solution ph. b) cation exchange capacity. c) percent base saturation. d) buffer ph. 12. The basic cations include a) Ca 2+, Na +, K +, H +. b) K +, Mg 2+, Al 3+, H +. c) Mg 2+, Ca 2+, Al 3+, K +. d) Na +, Mg 2+, K +, Ca 2+.

8 Quiz 3, February 17, 2006 Part 2. Short answer essay 13. List the three ways that nutrients move to plant roots along with a brief explanation of each. (6 points) 14. Convert 4 meq Calcium/100 g soil into parts per million. (Hint: The atomic weight of Calcium is 40 g/mole; the atomic weight of Hydrogen is 1 g/mole). (5 points) 15. List three ways that soils become more acid. (6 points)

9 Quiz 3, February 17, How much CaCO3 must be applied to an acre-6 of soil to neutralize 2 meq of acidity/100 g of soil? (The atomic weight of Calcium is 40 g/mole; the atomic weight of Carbon is 12 g/mole; the atomic weight of Oxygen is 16 g/mole; the atomic weight of Aluminum is 27 g/mole.) (5 points) 17. What is soil variable charge? What causes it to develop? (4 points, 2 points for each answer)

10 Quiz 4, March 3, 2006 Name: (-5 points if not legible) Part 1. Choose the one best answer. Each question is worth 2 points. 1. Reclamation of a sodic soil involves a) leaching with high quality water. b) incorporating gypsum and plant residues and leaching with high quality water. c) both of the above. d) none of the above. 2. You have a limestone recommendation of 2400 lb ECCE/a and a limestone material with an ECCE of 80%. How much of the material should you apply? a) 2400 lb/a b) 3000 lb/a c) 1920 lb/a d) 3200 lb/a 3. Under what conditions can CaSO 4 be used to change soil ph? a) Increase the ph of an extremely acid soil. b) Increase the ph of a saline soil. c) Decrease the ph of a sodic soil. d) Decrease the ph of a saline soil. 4. When you go home for spring break your father has a soil test that shows that one sample has a ph of 9.5 and EC = 5 mmho/cm. He tells you that the soil drains OK, but plants don t grow well there. What is the problem? a) The soil is saline. b) The soil is sodic. c) The soil is saline/sodic. d) I don t know! 5. Why don t we recommend applying Al 2 (SO 4 ) 3 to soils to decrease ph? a) It won t affect soil ph. b) It is too expensive. c) It causes the ph to decrease too rapidly. d) Aluminum is toxic to plants.

11 Quiz 4, March 3, Productivity of many crops is reduced 50% if the EC of the saturated extract is a) 1 mmho/cm. b) 2 mmho/cm. c) 3 mmho/cm. d) 4 mmho/cm or more. 7. If the acid neutralizing value (CCE) of a liming material is 90% and the fineness factor is 66.7% what is the effective calcium carbonate equivalent? a) 6000% b) 600% c) 60% d) 6% 8. The best way to apply limestone to ensure the maximum effect is to a) broadcast it on the soil s surface and let rainfall wash it into the soil. b) mix it into the soil using some form of tillage. c) inject liquid lime into the seed row. d) All of the above work the same. 9. The essential nutrient that limits microbial activity in soils is a) nitrogen. b) phosphorus. c) carbon. d) molybdenum. 10. The best way to maintain soil organic matter levels is to a) occasionally apply a high rate of animal manure. b) be sure the soil has adequate drainage. c) add limestone to maintain soil ph. d) apply appropriate rates of nitrogen fertilizer and return plant residues to the soil. 11. Transformation of ammonium (NH 4 + ) to nitrite (NO 2 - ) in soils is done by a) Nitrosomonas. b) Rhizobium. c) Nitrobacter. d) Bradyrhizobium.

12 Quiz 4, March 3, Before the 1960 s Iowa farmers used very little N fertilizer. Where did the N come from for corn production? a) It was fixed by lightening and rained onto the soil. b) It was fixed by legumes grown in rotation with the corn. c) The corn didn t need N. d) None of the above. 13. Microbial transformation of organic N into ammonia is called a) N fixation. b) Nitrification. c) Volatilization. d) Mineralization. 14. Loss of ammonia (NH 3 ) from the soil s surface is called a) denitrification. b) nitrification. c) leaching. d) volatilization. 15. The term denitrification means a) loss of nitrate from soils due to microbial transformation to N 2. b) loss of nitrate from soils due to leaching. c) loss of nitrate from soils due to volatilization. d) loss of ammonium from soils due to microbial transformation to N You incorporate a plant residue that has a carbon to nitrogen ratio of 60:1 into the soil. The net, short term effect will be a) nitrification. b) volatilization. c) mineralization. d) immobilization. 17. The amount of organic matter is soils a) is easy to increase. b) increases with tillage intensity. c) is not important. d) represents an equilibrium between additions and decomposition.

13 Quiz 4, March 3, If the surface 6 inches of a soil contains 3% organic matter how much is this in terms of pounds of organic matter per acre? a) 600 lb/a b) 6000 lb/a c) 60,000 lb/a d) 600,000 lb/a 19. The three fractions of soil organic matter are a) humic acid, fulvic acid, and humin. b) proteins, polypeptides, and ribonucleic acid. c) fulvic acid, proteins, and humin. d) humic acid, polypeptides and fulvic acid. 20. Soil organic matter plays an important role in e) formation of soil structure. f) decreasing drainage from soils. g) increasing soil susceptibility to compaction. h) development of negative charges due to isomorphous substitution. 21. The formation of chelates in soils is beneficial because e) chelates can make micronutrients like zinc more plant available. f) chelates can remove aluminum from the soil solution. g) they hasten microbial decomposition of soil organic matter. h) a and b i) a and c 22. The forms of nitrogen taken up by plants are a) NH 3 and NO 3 -. b) NH 4 + and NH 3. c) NO 3 - and N 2. d) NH 4 + and NO The organism that converts nitrite (NO 2 - ) into nitrate (NO 3 - ) in soils is a) nitrobacter. b) nitrosomonas. c) thiobacillus oxidans. d) rhizobium.

14 Quiz 4, March 3, Which of the following is not a difference between soil organic matter and plant residue? a) The origin of the residue is identifiable, but this is not true for soil organic matter. b) Soil organic matter has been chemically altered while plant residues have not. c) Soil organic matter gives the soil a light color while plant residues give it a very dark color. d) all of the above 25. Incorporation of inorganic N into microbial biomass is called a) nitrification. b) immobilization. c) mineralization. d) fixation.

15 Quiz 5, March 24, 2006 Name: (-5 points if not legible) Part 1. Choose the one best answer. Each question is worth 2 points. 1. The primary mineral used to produce phosphorus fertilizers is a) augite. b) variscite. c) strengite. d) apatite. 2. Why isn't H 2 PO 4 - mobile in soils? a) It's soluble. b) It's attracted to the soil's CEC. c) both a and b d) It's not soluble. 3. A common phosphorus fertilizer is diammonium phosphate. It has an analysis of What is the elemental P concentration in it? a) 46% b) about 20% c) about 90% d) about 2% 4. Anhydrous ammonia is the most commonly used form of N fertilizer in Iowa for corn production. a) true. b) false. 5. Why don't we use 32% N solutions in Iowa? a) Because they contain too much N and tend to burn the corn plants. b) Because they don't contain enough N so large amounts must be applied. c) Because they are too expensive. d) Because the fertilizer falls out of solution when the air temperature drops below 35 F. 6. Why is NO 3 - mobile in soils? a) Its soluble. b) Its not attracted to the soil's CEC. c) both a and b d) Its insoluble.

16 Quiz 5, March 24, The process used to industrially manufacture ammonia uses a) N 2 from the air and H from water to make the ammonia. b) organic N and H from water to make ammonia. c) organic N and H from methane to make ammonia. d) N 2 from the air and H from methane to make ammonia. 8. The form of nitrogen fertilizer that is most susceptible to N loss due to volatilization is a) ammonium sulfate. b) ammonium nitrate. c) urea. d) anhydrous ammonia. 9. Five gallons of 28% N solution contains how many pounds of N? a) 28 lbs. of N b) 70 lbs. of N c) 140 lbs. of N d) 15 lbs. of N 10. The late spring soil nitrate test used in Iowa is a) a measure of the amount of nitrate-n in the soil profile. b) based upon a calculation considering yield potential and a factor representing the amount of N required to produce a bushel of corn. c) an index used to estimate whether or not N fertilizer is required. 11. The process of industrial fixation of atmospheric N was invented by a) Bosch and Lomb. b) Priestly. c) Haber and Bosch. d) Bray and Kurtz. 12. Your father applied liquid N (a dissolved combination of ammonium nitrate and urea) to his corn last spring on a hot, dry day. The liquid was sprayed over the soil and not incorporated. The previous crop was soybeans. The growing season was a normal one. In August the corn showed N deficiency symptoms and yielded less than normal. What do you think happened? a) He lost N through leaching. b) The N fertilizer was immobilized. c) He lost N through denitrification. d) He lost N through volatilization.

17 Quiz 5, March 24, If used properly, all N fertilizer sources are equally effective for increasing crop growth and grain production. a) true b) false 14. The form(s) of phosphorus taken up by plants is/are a) H 3 PO 4 and H 2 PO 4 -. b) H 2 PO 4 - and HPO c) HPO 4 2- and PO d) P 2 O 5. e) none of the above. 15. The least amount of P is present in a) the soil solution (soluble P). b) organic forms. c) mineral forms. 16. The P soil test that was specifically developed to work on calcareous soils is the a) NaHCO 3 -P (Olsen P test). b) Mehlich III. c) Bray P-2. d) Bray P At soil ph's below 5, P forms insoluble compounds with a) aluminum, iron and calcium. b) calcium, magnesium, and potassium. c) manganese, iron, and aluminum. d) potassium, calcium, and manganese. 18. The best way to determine if phosphorus fertilizer is required is a) a plant tissue test. b) to wait until you see deficiency symptoms. c) a soil test. d) ask your neighbor. 19. How does phosphorus move to plant roots? a) diffusion. b) mass flow. c) root interception.

18 Quiz 5, March 24, The property that controls P solubility in soil is a) moisture. b) ph. c) temperature. Part 2. Short answer essay 20. You intend to incorporate corn residue into your fields this spring. You had the residue chemically analyzed and found that it is 40% carbon, 0.4% nitrogen, 1.5% phosphorus, and 2.0% potassium. If you incorporate 2 tons of this material into the surface six inches of soil in your fields, how much (if any) inorganic nitrogen will be immobilized if 50% of the residue decomposes? Please show all your work. (5 points) 21. How does low soil temperature affect P uptake by plants? (2 points) Why? (3 points)

19 Quiz 6, April 7, 2006 Name: (-5 points if not legible) Part 1. Choose the one best answer. Each question is worth 2 points. 1. The form of potassium taken up by plants is a) K -. b) K +. c) KCL. d) K 2 SO The pools of potassium that are reported as extractable in a soil test are a) K in solution and mineral K. b) K in solution and slowly available K. c) K in solution and readily available K. 3. An important function of potassium in plants is a) maintenance of plant turgor pressure. b) promotion of cell elongation. c) formation of chlorophyll. d) promotion of infection by mychorrizae. 4. The most common form of potassium fertilizer used for corn production in Iowa is a) KCL. b) K 2 SO 4. c) KNO Boron is taken up by plants as a) H 3 BO 3. b) H 2 BO 3 -. c) HBO d) BO Sulfur is a component of the amino acids a) cystine, alanine, and methionine. b) cysteine, alanine, and cystine. c) methionine, cysteine, and cystine. d) alanine, methionine, and cysteine.

20 Quiz 6, April 7, The major chloride fertilizer is a) CaCl 2. b) NaCl. c) Cl-EDTA. d) KCl. 8. The main source of Boron in soils is a) primary minerals. b) rainfall. c) soil organic matter. d) the cation exchange capacity. 9. A major source of sulfur in soil is a) mineralization from soil organic matter. b) decomposition of primary minerals. c) the cation exchange capacity. d) a and b. 10. The nutrient necessary for floral initiation is a) Boron. b) Chloride. c) Copper. d) Iron. 11. The micronutrient most likely to be deficient in peat and muck soils is a) Boron. b) Chloride. c) Copper. d) Iron In Iowa, most of the sulfur in surface soils is a) inorganic forms in the soil solution. b) organic forms in soil organic matter. c) inorganic forms on the cation exchange capacity. d) a and c. 13. Luxury consumption, taking up more of a nutrient than is required to reach maximum dry matter production, is especially a problem with a) potassium. b) sulfur. c) boron. d) chloride.

21 Quiz 6, April 7, Sulfur is taken up as a) SO b) S 2 O 5. c) FeS 2. d) SH Elemental sulfur (S) is not a good source of S to use to rescue S-deficient soybean plants because a) it takes several months to be converted into sulfate. b) its toxic to most plants. c) its impossible to find. d) it costs too much. 16. The form of copper taken up by plants is a) Cu -. b) Cu 2-. c) Cu +. d) Cu As ph decreases the availability of decreases. a) copper b) zinc c) molybdenum d) boron 18. Of all the nutrients, is present in the lowest amounts in plants. a) boron b) silicon c) iron d) molybdenum 19. The form of iron that is metabolically active in plants is a) Fe 2+. b) Fe 3+. c) FeS. d) Fe 2 O. 20. If the ph of the soil increases from 5.0 to 6.0, the solubility of Fe2+ a) Increases 10-fold. b) Decreases 10-fold. c) Increases 100-fold. d) Decreases 100-fold.

22 Quiz 6, April 7, 2006 Part 2. Short answer essay 21. Describe soil conditions that would favor leaching of potassium. (5 points) 22. How does compaction affect K + uptake by plants. Describe why this occurs. (5 points)

23 Quiz 7, April 21, 2006 Name: (-5 points if not legible) Part 1. Choose the one best answer. Each question is worth 2 points. 1. Molybdenum is taken up by plants as a) Mo 2- b) 2- MoO 4 c) MoSO 4 d) Mo The Iowa crop that is most sensitive to zinc deficiency is a) corn. b) soybean. c) alfalfa. d) oats. 3. The form of manganese that is active in plant metabolism is a) Mn 4+. b) Mn 3+. c) Mn 2+. d) Mn An element that is not required by plants but is required by animals and is generally low in Iowa soils is a) silicon. b) cobalt. c) copper. d) selenium. 5. The nutrients in animal manure are a) all in organic compounds. b) in both organic and inorganic forms. c) not available to plants. d) are not worth trying to use for crop production. 6. Zinc is taken up by plants as a) Zn +. b) Zn 2+. c) Zn -. d) Zn 2-.

24 Quiz 7, April 21, Animal manure contains all the essential nutrients except a) copper. b) manganese. c) phosphorus. d) it contains all essential nutrients. 8. A major problem with applying animal manure at a rate to supply the nitrogen requirements of crops is that a) you don't apply enough phosphorus. b) you don't apply enough potassium. c) you apply large amounts of phosphorus and soil test P increases dramatically. d) you apply too much sodium. 9. Some of the nitrogen in animal manure can be lost from the surface of the soil through the process of a) mineralization. b) immobilization. c) nitrification. d) volatilization. 10. The best way to determine the nutrient content of animal manure is to a) ask your neighbor. b) take a representative sample and have it chemically analyzed. c) look it up in a table. d) ignore it. It s not plant available anyway. 11. Application of Zinc fertilizer will decrease the uptake of a) nitrogen, phosphorus, and potassium. b) copper, iron, and manganese. c) calcium and boron. d) sulfur, molybdenum, and boron. 12. The two nutrients in animal manure that are of immediate environmental concern are a) nitrogen and sulfur. b) nitrogen and potassium. c) phosphorus and nitrogen. d) phosphorus and sulfur.

25 Quiz 7, April 21, How is nitrogen lost from animal manure during land application? a) leaching b) denitrification c) fixation d) volatilization 14. The plant availability of nitrogen in beef manure in the year of application is 35% because a) there are usually large losses of the N. b) the amount of phosphorus in the manure makes the N unavailable. c) much of the total N is in organic compounds and must denitrify before its plant available. d) much of the total N is in organic compounds and must mineralize before its plant available. 15. The nutrient that by law limits the rate of animal manure application in Iowa is a) Zinc. b) Nitrogen. c) Phosphorus. d) Copper. 16. Application of micronutrients such as manganese, iron, copper and zinc to insure that you don't have deficiencies is a good idea. a) true b) false 17. What would cause manganese to be in the Mn 2+ form in soils? a) excessive tillage. b) incorporation of high carbon:nitrogen plant residues into the soil. c) good soil drainage. d) poor soil drainage. 18. What process is responsible for conversion of organic forms of nutrients into inorganic (plant available) forms? a) volatilization b) nitrification c) mineralization d) immobilization

26 Quiz 7, April 21, The two micronutrient cations that are most affected by the oxidation/reduction status of the soil are a) iron and zinc. b) copper and iron. c) manganese and copper. d) manganese and iron. 20. The only micronutrient that we have soil test calibration data for in Iowa is a) Boron. b) Copper. c) Manganese. d) Zinc. Part 2. Short answer essay A hog producer stores the manure from his confinement buildings in an anaerobic lagoon. The liquid has a nutrient concentration of 4 lb N, 3 lb P 2 O 5, and 4 lb K 2 O per 1000 gallons. 21. How much of this liquid should be applied to meet the N fertilizer requirement for 150 bu/a corn? (2 points) 22. How much P 2 O 5 will be applied per acre? (2 points) 23. From an environmental view point, is this good management? Briefly explain. (6 points)