Irrigated Corn Management in Drought - Roozeboom - Agronomy

23 Pages·2012·1.68 MB·English

by  Gerry Snyder

Irrigated Corn Management in
Drought
Kraig Roozeboom – Agronomy
Dan Rogers – Bio. & Ag. Engineering

Objective
• Equip viewers to evaluate irrigated corn fields
to document support for management
alternatives in drought:
– Continue irrigating entire field
– Divert irrigation water to a portion of the field and
abandon the rest
– Stop irrigating the entire field and abandon it or
harvest it for forage
Outline
• Roozeboom
– Corn Growth & Development and Effect of Heat
and Drought
– Estimating Yield Potential
• Rogers
– Corn Water Use
– Balancing Corn Water Use and Irrigation Capacity
Stages of Corn Development
Vegetative Reproductive
Vegetative
leaf formation pollination and
tassel and ear formation
grain fill
• VE emergence, leaf • V6 stalk elongation
and ear shoot begins, tassel initiation • R1 silking, pollination
initiation
• V8 • R2 blister
• V1
• V10 • R3 milk, rapid starch
• V2 • V12 row number set deposition
• V3 • V14 • R4 dough
• V4 • V15 silks growing • R5 dent, kernel no. set
• V16-17 kernels/row set
• V5 leaf number set, • R6 PM
all ear shoots formed • V(n) pollen formation (black layer)
• VT tassel emergence
Leaf Area - Yield Loss Relationships
100
90
80
s
s 70
o
L
d 60
l
e
i 50
Y

t
n 40
e
c 100
r 30
e Percent
P 70
20
Leaf Area
40
10 Loss
0 10
5V 6V 7V 8V9V 01V 11V 21V 31V 41V 51V61V 81-71V lessaT kliS nworB skliS retsilb-erP retsilB kliM ylraEkliM kliM etaL hguoD tfoS tneD ylraE tneD tneD etaL erutaM raeerutaM
N
Growth Stage
Ritchie, S.W., J.J. Hanway, and G. O. Benson. 1993. How a corn plant develops. SR 48.
Iowa State University Cooperative Extension Service. Ames, Iowa.
Temperature and grain fill

e
r
c
a
/
s
l
e
h
s
u
b
day/night temperatures (F)
Badu-Apraku, B., R.B. Hunter, and M. Tollenaar. 1983. Effect of temperature during grain
filling on whole plant and grain yield in maize (Zea Mays L.). Can. J. Plant Sci. 63:357-363.
Temperature and grain fill
Grain fill trait 77/68°F 93/77°F Change
%
Rate mg/kern/HU 0.55 0.42 -24
Duration, HU 333 403 21
Rate mg/kern/day 7.4 8.8 19
Duration, days 24.4 19.4 -22
Wilhelm, E.P., R.E. Mullen, P.L. Keeling, and G.W. Singletary. 1999. Heat stress during grain filling in maize:
effects on kernel growth and metabolism. Crop Sci. 39:1733-1741.
Temperature and grain fill
• ~72
– ideal temperature for grain fill in corn
• 80 to 95
– rate of grain fill starts to slow down
– even if roots are kept at normal soil temperatures
from the shading of the canopy
• 105 to 110
– Grain fill rate , but grain fill duration 
– yield losses likely to occur