Thomas Marek, Qingwu Xue, Wenwei Xu, Jake Becker, G.J. Michels, T.A. Howell, P. Gowda, S.H. Amosson, Bridget Guerrero, P.D. Colaizzi and J.M. Sweeten

Controlled Protocol details:

• Up to 12 inches of pumped irrigation water only

• 3 commercial corn hybrids,

• 4 planting populations, (20, 24, 28, & 32K)

• Plots laid out with AMS system

• Strip till pre-fertilized with in-season fertilized

• A sponsored project by the OAP, the NPGCD & the TCPB.

Daily corn ET demand in Etter, TX (2010-2012)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

4/12 5/2 5/22 6/11 7/1 7/21 8/10 8/30 9/19 10/9

Da

ily

ET

(in

)

2010, 33 in

2011, 46 in

2012, 37 in

Source: TXHPET Network

2012 Soil Profile Water -12-200

0

50

100

150

200

250

10 15 20 25 30 35

Co

rn Y

ield

. bu

/ac.

Total Crop Water , in.

Corn Production Function (Field data-heavy clay soil)

2010 NPRF Yield

2011 NPRF Yield

2012 NPRF Yield

1. Drought based events are part of the rainfall probability

distribution f(x) and they do occur and can have significant

consequence on corn production levels,

2. Crop production f(x) s are key to understanding

production potentials and we greatly enhanced our current

function in terms of yield with this study,

3. Irrigation depth per application generally should be

increased to the point that application runoff either does

not occur or is minimal (in terms of applied water

advancing forward of the application device) to reduce soil

evaporation losses (but should be limited to depleted

water within the soil root zone profile),

4) Manage upper soil profile cracking to the degree

possible with irrigation applications and allow for

maximum opportunity regarding rapid infiltration

potential should large rainfall events occur,

5) Implement a delayed corn planting date to shift the

peak corn ET requirement and to take advantage of

reduced ET requirements typical in the early fall

period

• Often unrestricted early season plant growth occurs (2012)

…so need growth restriction

•

• Possible differing ways to address this:

…1) early season growth regulator(s) and/or

…2) select hybrid(s) that have a lower ear height

• …3) possible use of a shorter maturity variety

• …the answer(s) is/are not known.

Sunset at the NPRF, 2012