AGRONOMY 375 EXAM III December 10 and 13, 2013 100 points possible Name There are 15 questions plus a bonus question, each of which requires a short answer. Please be concise. Best wishes for your success! 1. A portion of a row is uncovered to check planter calibration in the field. The following distances are recorded between successive seeds in this row segment. Row width is 30 inches. Please show your work. 5 inches 3 inches 16 inches 4 inches 2 inches 4 pts. a) The actual seeding rate for this row segment is seeds/acre 4 pts. b) What level of standard deviation (from uniform spacing) is presented in this row segment? 4 pts. c) What yield loss due to poor precision (above the theoretically possible level of precision for a well operated and maintained planter) is likely at this level of planting precision? bushels per acre 6 pts. 2. Briefly describe three factors which contribute to increased yield and / or profit potential for corn planted early (e.g. April 25 vs. May 10) in most years in central Indiana. a) b)
2 c) 4 pts. 3. Describe what is meant by a structured refuge in the context of corn Insect Refuge Management and contrast that type of refuge with refuge in a bag (RIB). 6 pts. 4. Describe each of the following for commercial dent corn in central Indiana: a) V stage at which the growing point is first above ground. b) Visible indicator that a plant has reached R4. c) Visible indicator that a plant has reached R5. 4 pts. 5. For a medium texture soil at field capacity approximately how much water (inches) is plant-available per four feet of rooting depth? 4 pts. 6. a) What is the optimum seeding date for Soft Red Winter Wheat in the Midwestern U.S.? ( Note: Your answer should apply equally well to any location in the Soft Wheat area.) 2 pts. b) What is the range of Hessian Fly Free Dates for Indiana (northern to southern)?
3 6 pts. 7. a) What is the optimum established stand density for Soft Red Winter Wheat in Indiana? plants / square foot b) If a given drill row width is 7 inches how many inches of drill row distance (one row wide) constitutes a square foot of area for purposes of drill calibration? Please show your work. 9 pts. 8. The following pertain to a proposed crop of Indiana wheat; Yield goal = 85 bushels per acre Previous crop = 53 bushels of soybeans per acre 15 pounds of N are to be applied per acre at seeding with the balance of N to be applied as a topdressing in the Spring. a) What Spring topdressed N rate is appropriate to recommend? Lbs. N / Acre b) What maintenance P2O5 rate should be applied? Lbs. P2O5 / Acre c) What maintenance K2O should be applied? Lbs. K2O / Acre 4 pts. 9. a) At what wheat developmental stage should topdress N be applied in the Spring? 4 pts. b) Why at this stage? Please be specific and provide two reasons.
4 6 pts. 10. Note the appropriate maintenance P2O5 and K2O rates for a 60 bushel per acre soybean yield. (Please show your work). Lbs. P2O5 / Acre Lbs. K2O / Acre 11. Compare a mid Maturity Group III vs. an early Maturity Group IV indeterminate soybean variety with respect to each of the following (assume both are planted on the same day at the same location in central Indiana, in the same row width and at the same population). 4 pts. a) Flowering date of a mid Maturity Group III vs that of an early Maturity Group IV. 4 pts. b) Mature plant height of a mid Maturity Group III vs that of an early Maturity Group IV. 6 pts. 12. Assume a hoop with diameter 30 inches has been used to estimate stand counts in a drilled soybean field. An average of 22 plants were surrounded by the hoop in this field. What is the estimated population (plants per acre) for this field? (Please show your work). 5 pts. 13. How can a producer know if they have optimized row width (with respect to their choice of drill vs. close vs. wide row spacing) with regard to accomplishing optimum light harvest and removing that as a factor potentially limiting to yield?
5 14. Note a quantifiable characteristic which uniquely indicates that a soybean plant is at each of the following; 2 pts. a) R2 growth stage 2 pts. b) R 3 growth stage? 2 pts. c) R 4 growth stage? 2 pts. d) R 5 growth stage? 6 pts. 15. a) What is the approximate recommended established population for Indiana Soybeans in 6 inch row width? plants per foot of row. plants per acre. b) What is the approximate recommended established population for Indiana Soybeans in 15 inch crow width? plants per foot of row. plants per acre. c) What is the approximate recommended established population for Indiana Soybeans in 30 inch row width? plants per foot of row. plants per acre.
6 5 pts. BONUS What is the developmental stage of the soybean plant pictured below? (Note that three trifoliolate leaves have leaflets with margins no longer touching while the fourth trifoliolate leaf has margins that are yet touching.) Have A Blessed and Merry Christmas, Joyeux Noël! CONGRATULATIONS TO THE GRADUATES!