Precision Agriculture in Arizona: A New Research and Extension Program

Pedro Andrade-SánchezAgricultural and Biosystems Engineering DepartmentMaricopa Agricultural Center, University of Arizona

Modern technology for Precision Agriculture

Presentation Outline

Variable rate technology in Cotton

Soil Electrical Survey. 20 ha field in Safford, AZ

Veris sensor. Apparent Electrical Conductivity (ECa)

VRT in Cotton. Prescription Mapping

Soil texture prediction. 20 ha field in Safford, AZ

y = -1.245x + 63.151

R2 = 0.780

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Apparent Electrical Conductivity (mS/m)

Pe

rce

nt

Sa

nd

Note: Preliminary tests at MAC show potential for salinity assessment

Detection of subsoil compaction

CIEi = 0.216 CIi + 2.601 di - 0.176 CIi di

(R2 = 0.973)

0.0

0.5

1.0

1.5

2.0

0.0 0.5 1.0 1.5 2.0

CIE (MPa)

Pre

dic

ted

CIE

(M

Pa

)

CIEi*= 0.216*(2.0 MPa) + 2.601 di - 0.176*(2.0 MPa) di

Mapped quantity: CIEi / CIEi*

Algorithm for compaction assessment

CIEi = Cone Index Equivalent (of the ith layer)

Draft and Fuel Consumption

Current work: Tractor Instrumentation

From N.E. Boon et al., 2005

Canopy multi-spectral reflectance

Effect of defoliation after 4 hours

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0 3 6 9 12 15 18Days after defoliation

NIR

can

op

y re

flec

tan

ce (

%)

Control 25% 50% 75% 100%

40

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75

0 3 6 9 12 15 18Days after defoliation

NIR

can

op

y re

flec

tan

ce (

%)

Control 25% 50% 75% 100%

Date 1 (June 20)

Date 2 (July 7) Date 3 (July 21)

40

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75

0 3 6 9 12 15 18Days after defoliation

NIR

can

op

y re

flec

tan

ce (

%)

Control 25% 50% 75% 100%

Biomass dynamics (NIR band – 880 nm)

Auto-guidance: Extending infrastructure utilization

Auto-guidance: Linear distribution of plants

Auto-guidance: Linear distribution of plants

Easting Error = Ei – Ea-b

Planting w/ Autoguidance Conventional Planting

Yield monitoring

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0.5

1.0

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3.0

3.5

4.0

3659245 3659255 3659265 3659275 3659285

Northing (m)

Ma

ss

flo

w r

ate

(lb

/se

c)

Yield monitoring: Small plot research

Note: In 2009, yield monitoring using GPS-RTK improved spatial resolution

Future Work: Variable Rate Irrigation

Information Loop for Variable Rate Irrigation

Chavez et al. 2007

Control System for Variable Rate Irrigation

Chavez et al. 2007