enhancing water conservation and crop...

United States Department of Agriculture

Agricultural Research Service

U.S. Arid Land Agricultural Research Center, Maricopa, Arizona

Enhancing Water Conservation and

Crop Productivity in Irrigated

Agriculture

Kelly R. Thorp

Kevin Bronson, Doug Hunsaker, Andrew French

USDA-ARS-ALARC, Maricopa, Arizona




Background

• U.S. Department of Agriculture• Agricultural Research Service (ARS)

– Main research arm of USDA– 2,200 research scientists– 800 research projects– 90+ research locations

• Arid-Land Agricultural Research Center– Maricopa, Arizona (south of Phoenix)– 3 research units

• Pest Management and Biocontrol• Plant Physiology and Genetics• Water Management and Conservation

– 23 research scientists– Co-located at University of Arizona farm




Water Unit Research ScientistsKevin Bronson

Soil Scientist & Research LeaderNitrogen Fertilizer Management

Eduardo BautistaResearch Hydraulic Engineer

Hydraulic Modeling

Doug Hunsaker Research Agricultural EngineerIrrigation Water ManagementSoil Moisture Measurement

Andrew French Research Physical Scientist

Remote Sensing of Evapotranspiration

Clinton WilliamsResearch Soil Scientist

Wastewater Reuse

Fedja StrelkoffResearch Hydraulic Engineer

Hydraulic Modeling

Kelly Thorp Research Agricultural Engineer

Remote SensingComputer Simulation Modeling

Agricultural Information Technologies

?Vacant

Research MicrobiologistWastewater Reuse




Water Management Research Activities

• Agronomic Field Investigations– Develop crop coefficients for irrigation scheduling– Improve crop water use efficiency– Understand yield-water-nutrient relationships– Improve management of traditional and bioenergy crops

• Remote and Proximal Sensing Technology– Develop crop sensing and data processing techniques– Monitor crop water and nutrient stress site-specifically– Understand spatial and temporal variability

• Computational Methods and Analysis– Develop and apply cropping system simulation models– Integrate crop sensing data with simulation models– Develop geographic information systems for spatial data analysis– Develop decision support systems for water and nutrient

management




Precision Irrigation ManagementRemote sensing of crop coefficients for ETc

Meters0 60 120 180 240

EM-38 survey for soil water properties

ECa ≈ Soil water holding capacity98 mm/m (dark) to 158 mm/m (light)

Simulated variation in soil water depletion determines irrigation timing, amount and location

Cotton lint yield map (Blue higher yield)




Water Use Efficiency for New CropsBiomass sorghum Switchgrass

Guayule for natural rubber Transplanting guayuleInstalling drip irrigationguayule experiment

Bioethanol crops: Agave




Deficit Irrigation Management

• Field investigation• Crops

– Durum wheat– Camelina (for biodiesel)

• Gradient irrigation– Linear move sprinkler– Arizona environment

• Variable nitrogen rates

Seasonal irrigation, mm

0 100 200 300 400 500 600 700G

rain

Yie

ld (

raw

wei

ght)

, kg/

ha

0

2000

4000

6000

8000

10000

12000

Linear Move Sprinkler




Fate and Management of N Fertilizer

• Field investigations in furrow irrigated cotton• UAN fertigation versus side-dress knifing• Canopy spectral reflectance observations• Nitrous oxide emissions from soil

Nitrogen fertigationObserving nitrous oxide emissions from soil

Side-dress knifing of nitrogen fertilizer




Remote Sensing of Evapotranspiration

LST (Thermal IR)

NDVI

Airborne Image Data Wireless Sensor Data ET Modeling

10 min. LST

Daily ET




Wireless Networked Sensors• Real-time, time continuous, spatially distributed, low-cost monitoring• Experiments at MAC and nearby farms• Sensors:

• Infrared thermometers• In-field weather• Soil moisture • Vegetation index radiometers

• Wireless Network• Low-power, low-data rate, lower cost, multiple units• Reliable, accurate• Semi-automated

• Network mesh, XML/RPC• Zigbee or equivalent

Wireless Node Infrared thermometers & VNIR radiometers Soil moisture probe deployment




ET Estimation at Multiple Scales

Day of year, 20050 20 40 60 80 100 120 140 160

Bas

al C

rop

Coe

ffic

ient

, Kcb

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8Standard FAO-56 Kcb model for wheat NDVI-adjusted Kcb for densely-planted wheatMeasured Kcb for densely-planted wheat

FAO behind measured 9-16 days

FAO ahead of measured 10-17 days

Low-altitude airborne remote sensing

Temperature NDVI

Ground-based radiometry

Airborne remote sensing surveys

Plot Scale Farm Scale Regional Scale

Hand-held and Vehicle-based Proximal Sensing

Satellite-based remote sensing

Thermal IR satellite imagery




Hyperspectral Remote Sensing

• Spectroradiometers– ASD FieldSpec– GER 1500– Hundreds of bands

• Spectral analysis– Find sensitive

wavebands

– Develop vegetation indices and models




Cropping System Simulation Modeling

• Computer simulations– Input management, cultivar, weather, and soil information– Simulate carbon, nitrogen, and hydrologic processes– Simulate crop growth and development processes– Simulate on daily or hourly time steps– Output crop yield, ET, N fate, etc.

• Many models available– DSSAT, Aquacrop, APSIM, STICS, WOFOST, InfoCrop,

CropSyst,

– Variable complexity and simulation detail• Require calibration against field observations• Test alternative management scenarios (what if?)




Sensor Data and Model Fusion

• Combine RS and Crop Models– Mathematical methods– Data assimilation– Model optimization

• Sensor Data– Infrequent– Spatially distributed

• Simulation Model– Temporal continuity– Adjusted to sensor data– Forward prediction

VIS/NIR Images Thermal Images

PROSAILEnergy

Balance

Crop

Growth

Water

Balance

Nitrogen

Balance

Cropping Systems Model

Assimilation/Optimization

ET, N Fate, Crop Yield, etc.




GIS & Geospatial Analysis Tools




Industry Collaboration

• USDA-ARS Scientist Responsibilities– Conduct scientific research for public interest– Publish results in peer-reviewed scientific journals– Participate in professional societies– Technology transfer

• Mechanisms for Collaboration– Participation in tech transfer workshops and demo projects– Cooperative Research and Development Agreements– Find a scientist in your area of specialization– Inexpensive access to skilled research personnel




Questions?

enhancing water conservation and crop...

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