Name
AGRONOMY 375
EXAM III
100 points possible
There are 15 questions plus a bonus
question, each of which requires a short answer. Please be concise. Best wishes for your success
!
6 pts.
1. Please describe the following
for the Corn;
a) Visible indicator that Corn is at the R5
growth stage.
b) Procedure to correctly identify V stage
when the lower leaves have been removed by a hail storm or other means.
c) Grain moisture content (%) when the
"milk line" (on the endosperm side of the kernel) has reached a
position one - half way between the broad end and the tip of the kernel.
10 pts. 2. Compare
the drought tolerance of soybean yield to that of corn yield.
Provide two
reasons for the greater yield stability of the most drought-tolerant crop.
10 pts. 3. Briefly
discuss the suitability of the
2 pts. 4. 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.)
4 pts. b)
What risks does a wheat producer incur if seeding wheat earlier or later than
the optimum date?
Earlier:
Later:
6 pts. 5. a) What is the optimum established stand density for Soft
Red Winter Wheat in
________________plants / square foot
b) Estimate the
potential yield (bushels per acre) for a crop of wheat which, when assessed
after jointing has begun has an average of 3 productive stems (1 main stem plus
2 tillers) per each of 20 plants per square foot. Please show your work.
_______ bushels
/ acre
c) How many
inches of wheat row should one count as a square foot when assessing wheat
stand in a field seeded to 7 inch drill rows. Please
show your work.
6 pts. 6. The
following pertain to a proposed crop of
Yield goal = 85
bushels per acre. Previous crop = 60 bushels of soybeans per acre.
20 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 /
b) What
maintenance P2O5 rate should be applied
?
_______Lbs. P2O5 /
c) What
maintenance K2O should be applied ?
________Lbs. K2O /
6 pts. 7. At
what wheat developmental stage should topdress N be applied in the Spring ? Why at this stage ? Please
be specific and provide at least two reasons.
5 pts. 8. Describe the typical weed control program
for Soft Red Winter Wheat produced in
6 pts. 9. Note
the appropriate maintenance P2O5 and K2O rates
for a 60 bushel per acre soybean yield. (Please show your work).
________ Lbs. P2O5 /
________ Lbs. K2O /
5 pts. 10. Note the approximate plant available water supply for a medium
textured (e.g. Silt Loam) soil at field capacity (fully supplied with water so
it is holding all it will hold, the surplus having drained away).
________
inches of plant available water per foot of rooting depth.
6 pts. 11. Describe two visible differences evident between an Indeterminate
and a Determinate soybean variety of comparable relative maturity group III planted on
the same date in central
a)
b)
5 pts. 12. What rule of thumb can be used to indicate whether a decrease in
soybean row width (e.g. from 30 inches down to 7 inches) is likely to produce a
potential yield increase in a given situation? Please explain your answer.
7 pts. 13. Is there a likely greater
or smaller advantage for drill-row
(e.g. 8 inch row width) vs. wide row (e.g. 30 inch) for soybeans in central
Indiana as planting date is delayed from May 15 to June 15? Please be thorough
in explaining your answer.
10 pts. 14. Note
a quantifiable characteristic which uniquely indicates that a soybean plant is at the;
a) V 1
growth stage?
b) R 1 growth stage?
c) R 4
growth stage?
d) R 5
growth stage?
e) R 6
growth stage?
6 pts. 15. What is the approximate
recommended seeding rate for Indiana Soybeans in each of the following (assume 100%
germination and establishment)?
a) 30 inch row
spacing
Seeds per
foot of row. Seeds per acre.
b) 6 inch row
spacing
Seeds per
foot of row. Seeds per acre.
c) Compare the
potential for irregular emergence through surface - crusted soil conditions
when soybeans are seeded with a drill
with 6 inch row spacing vs. when
soybeans are planted in 30 inch row width. Please explain the difference.
5 pts. BONUS Assume a hoop with diameter 27 inches has been used to
estimate stand counts in a drilled soybean field. The average plant density in
the area surrounded by the hoop was 18. What is the estimated stand density for
this field? (Please show your work).
________
Plants / Acre
HAVE A GREAT SUMMER!
CONGRATULATIONS TO THE GRADUATES !