Agronomy in the Context of Conservation Agriculture:

Nutrient Management

Eric Miller, Ivan Ortiz-Monasterio, and Bill Raun

Beyond Diagnostics: Insights and Recommendations from Remote Sensing

December 14th, 2013

Update on the Trimble® GreenSeeker handheld crop sensor

Progress with the OSU singulating hand-held planter ◦ Capable of singulating corn seeds and applying

fertilizer nitrogen as urea beneath the soil’s surface

Talking points

Sensor Extension, Ciudad Obregon, MXDr. Ivan Ortiz-Monasterio

Trimble® GreenSeeker handheld crop sensor

Objective◦ Develop a small and cost-effective NDVI sensor to

duplicate the results of a commercial GreenSeeker sensor (Crain et al., 2012)

Picture courtesy of Jared Crain

MSRP $495 USD

Handheld sensor

Relationship with the GreenSeeker

0.0 0.2 0.4 0.6 0.8 1.00.0

0.2

0.4

0.6

0.8

1.0

f(x) = 0.96926977718988 x + 0.0548179444811671R² = 0.872395617435364

Handheld NDVI

Gre

en

Seeker

ND

VI

Slope = 1 Intercept = 0

Regression model parameters

Model parameters and analysis of variance; slope equal to 1 and intercept equal to 0

Sensor ReadingsParameter of the

model† R2 nSignificance

(Pr > F)

NDVI a b Intercept Slope

All 0.05 0.97 0.88 1485 <0.001 0.001

Greater than 0.50 -0.08 1.21 0.72 160 0.002 <0.001

Less than 0.50 0.07 0.93 0.78 1325 <0.001 <0.001

† a = intercept, b = slope

nue.okstate.edu

#6 Trigo (Mexico)

nue.okstate.edu

OSU singulating hand-held planter

Opico Quezaltepeque, El Salvador

http://okstate.edu/

Remove chemically treated seeds from the hands of small farmers

Decrease soil erosion via improved plant spacing

Accommodate mid-season application of fertilizer (N and P)

Place urea below the surface reducing NH3 losses

Potential to increase third-world maize production and NUE

Benefits

Hand planter iterations

875,098,631 Mg maize 176,991,927 ha of maize

◦ 4.95 Mg ha-1

>50,000,000 ha in the developing world

60% planted by hand◦ 20,645,000 ha or 13% of the

total maize area in the world

Potential impact

FAOstat, 2013

Hand Planter Testing: 2013

Ciudad Obregon, MXDr. Ivan Ortiz-

Monasterio

1,000,000 cycles0.29g/seed60,000 seeds/ha3443 seeds/kg1.0 kg hopper 17 times refill

nue.okstate.edu/Hand_Planter.htm

seed size (2653-4344 seeds/kg)

seed type and shape fertilizer

Third world maize yields hover near 2.0 Mg ha-1 (Dowswell, et al., 1996)

“OSU Hand Planter”

Drum, tip, orientation, cavity (seed size, brush, housing,

user)

4 6 8 10 120

20

40

60

80

100 P-450

P-260

R-450

R-260

T-P450

T-P-260

T-R-450

T-R-260

checkDays after planting

Emer

genc

e, %

Maize emergence delayed by as few as four days, resulted in a yield depression of 15 percent (Hodgen et al., 2007)

Homogeneity in maize plant spacing, plant stands, and emergence can decrease plant-to-plant variation and increase grain yields (Nielsen, 1997; Martin et al., 2005)

Thailand Mexico ZambiaEl Salvador Guatemala

Questions?