AGRONOMY 375 EXAM III. December 11 and 13, points possible

Transcription

1 Name AGRONOMY 375 EXAM III December 11 and 13, points possible There are 16 questions plus a bonus question, each of which requires a short answer. Please be concise. Best wishes for your success! 6 pts. 1. 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) c) 2 pts. 2. a) A given field in west central Indiana was in corn in 2011 and in soybeans in When and how should the field be scouted (or when and how should the field have been scouted) in order to determine the need for an insecticide for CRW refuge or non-traited corn (seed coating or soil applied at planting) or a Bt corn rootworm hybrid in 2013 to achieve economic control of corn rootworm larvae in that corn crop? 2 pts. b) Under these conditions, what is the appropriate economic threshold above which a soil or seed coating insecticide should be applied or a Bt corn rootworm hybrid should be planted to control corn rootworm larvae in the 2013 corn crop?

2 2 4 pts. 3. This field will be going back to corn in 2014 again at an intended harvest population of 32,000 plants per acre. What scouting procedure and economic threshold should be implemented in 2013 to determine that need for an insecticide for CRW refuge or non-traited corn (seed coating or soil applied at planting) or a Bt corn rootworm hybrid in 2014 to achieve economic control of corn rootworm larvae in that corn crop? 4 pts. 4. 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. 5. Please note the following as they pertain to Corn growth; a) Visible indicator that Corn has reached the R2 growth stage. b) Procedure to correctly identify V stage when the lower leaves have been removed by a hail storm or other means. c) Visible indicator that corn has reached the R 4 growth stage. 10 pts. 6. Compare the drought tolerance of soybean yield to that of corn yield and provide two reasons for the greater yield stability of the most drought-tolerant crop.

3 3 4 pts. 7. 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). 6 pts. 8. 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 for full credit. 9 pts. 9. The following pertain to a proposed crop of Indiana wheat; Yield goal = 95 bushels per acre Previous crop = 55 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

4 4 c) What maintenance K2O should be applied? Lbs. K2O / Acre 6 pts. 10. At what wheat developmental stage should topdress N be applied in the Spring? Why at this stage? Please be specific and provide two reasons. 6 pts. 11. Note the appropriate maintenance P2O5 and K2O rates for a 58 bushel per acre soybean yield. (Please show your work). Lbs. P2O5 / Acre Lbs. K2O / Acre 12. 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. 13. Assume a hoop with diameter 29 inches has been used to estimate stand counts in a drilled soybean field. An average of 25 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 5 5 pts. 14. 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? 15. Note a quantifiable characteristic which uniquely indicates that a soybean plant is at each of the following; 2 pts. a) R1 growth stage 2 pts. a) R 3 growth stage? 2 pts. b) R 5 growth stage? 2 pts. c) R 6 growth stage? 6 pts. 16. 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.

6 6 plants per acre. 5 pts. BONUS. Please draw a soybean plant at the V3 stage and label the cotyledons, the unifoliolate leaves, the trifioliolate leaves and the uppermost leaf with margins no longer touching. HAVE A BLESSED AND MERRY CHRISTMAS! CONGRATULATIONS TO THE GRADUATES!