Exam 2 on Soil Fertility Management | SOCR 350, Exams of Soil Mechanics and Foundations

Download Exam 2 on Soil Fertility Management | SOCR 350 and more Exams Soil Mechanics and Foundations in PDF only on Docsity! Name_____________________________ Soil Fertility Management SC 350 / Exam 2 November 8, 2006 Circle the underlined correct answer(s) on multiple choice or write the answer in the blank where appropriate. The number in parenthesis indicates the points for each question. Show work on problems. GIVEN: 1% O.M. supplied 30 lb. N/A Legume contributions: Manure supplies 10 lb. N/T Alfalfa - 50 lb. N/A 2.7 x ppm = lb/A Ft. H2O Beans - 30 lb. N/A Alfalfa Grass - 30 lb. N/A ppm x 3.6 = lb. NO3-N/foot/acre ____________________________________________________________________________________ 1. (8) You just purchased a bag of fertilizer and it has the following printed on the bag: 12-19-4- 2Fe. What does this mean (be very specific regarding the form guaranteed in the analysis)? 2. (5) Below is the N cycle from your class notes. In the blanks provided below, describe if the various N tranformations are mineralization, immobilization, aminization, denitrification, ammonification, or urea hydrolysis. 1. ___________________________ 4. _________________________ 2. ___________________________ 5. _________________________ 3. ___________________________ 3. (4) Circle the cultural practice, soil, or landscape characteristic that would result in a higher P index risk. a. Application of manure vs. inorganic P fertilizer b. Landscape with a 1% vs. 6% slope c. Soil with an infiltration rate of >2.0in/hr vs. <0.2in/hr d. Spring application of manure with immediate incorporation into soil vs. fall application with spring incorporation 4. (6) a. Why are two different extractants required for acid and basic soils? (In other words, why can’t we use one extractant for all soils?) b. Describe the function (chemical reactions) of NaHCO3 during the extraction process in alkaline soils. (Description in words is adequate) 5. (12) You have the following chemical analysis of a soil from a field where you want to grow giant pumpkins. A good crop of giant pumpkins will require 300 lb N/A. What is your N fertilizer recommendation? a. What is the cost/lb of N and P2O5 in each fertilizer material? b. You are going to broadcast apply the fertilizer. Which materials would you use? Why? c. You are going to band apply all the P with the seed. Which P source would you use? Why? d. The fertilizer recommendation is 200 lb N/A and 50 lb P2O5/A. How many pounds of urea and DAP would you broadcast apply? 10. (6) Describe in words how you manufacture diammonium phosphare (DAP. (Five points extra if you give me the complete chemical reactions!) 11. (6) The use of high rates of N on turf can have both positive and negative effects on the plant. List 4 positive and 2 negative effects of excessive N application to turf. 12. (6) What are the advantages and disadvantages of using slow release N fertilizers as compared to highly water soluble N fertilizers? 13. (10) Using the solubility diagram and the given chemical reactions (below), answer the following questions. Given: 1. AlPO4 ● 2H2O + H2O <-----> Al (OH)3 + H+ + H2PO4- 2. HPO42- + H+ <-----> H2PO4- 3. CaHPO4 ● 2H2O + CO2(g) + H2O <-----> CaCO3 + HPO42- + 2H+ + H2O 4. CaHPO4 ● 2H2O + H+ <-----> Ca2+ + H2PO4-+ H2O 5. None of the above a. What would be the first stable reaction product formed in the soil if you added APP (ammonium polyphosphate) fertilizer to the following soils: Soil A Soil B pH = 7.4 pH = 5.9 Answer: __________________ Answer: __________________ b. You have a soil that has a pH of 5.0. You add enough lime to the soil to change the pH by 1.0 unit. 1. The final pH of the soil will be _______________. 2. The concentration of H2PO4-2 and HPO4-2 ions in equilibria with the soil will be _____________________ after liming. 3. Reaction __________ describes what is happening in the soil and the reaction is going to right, left. c. You are going to grow and “acid loving” crop. You need to acidify the soil using elemental sulfur. The current soil pH is 7.2 and you want to decrease the pH to 6.5. 1. The P availability of the soil will increase, decrease upon addition of sulfur. 2. The concentration of H2PO4-1 and HPO4-2 will be _____________ at pH 6.5. 3. Reaction _________ describes what is happening in the soil and the reaction is going to the right, left. 14. (7) Answer the following questions (circle the correct choice). True False The atmosphere is composed of 78% N2 and this is the source of N for fertilizer N manufacturing.