Crop Modeling,The 2012 “Flash Drought”

& Irrigation Demand

Cameron HandysideUniversity of Alabama in Huntsville

Earth Systems Science CenterSeptember, 2013

Decline in Alabama commodity crops was characteristic of Southeast as a whole

Background

Irrigated

Rainfed

Midwest Yields

Yield Benefit of Irrigation

Profit while paying for irrigation infrastructure

How do we run these scenarios?

Soil Conditions Weather data

Model Model

Simulation Simulation

Crop Management Genetics

GrowthGrowth DevelopmentDevelopment

YieldYield

Net IncomeNet Income

Environmental ImpactEnvironmental Impact Natural Resource UseNatural Resource Use

Crop Model

DSSAT

• “Decision Support System for Agro-Technology”• Computer simulation model of the soil-plant-

atmosphere system• Widely accepted crop model• Used to model “What-if” scenarios incorporating

multiple factors (weather, soil, cultivar, irrigation…)

• Inputs:• Min/Max Temperature• Precipitation• Insolation (sunshine)• Soil

• Outputs:• Yield• Drought Stress• Irrigation Demand• Fertilizer Demand• Residual Fertilizer

DSSAT to GriDSSAT Workflow

RunDSSAT

~36,000 times a

day!

“X File”:• Planting Dates• County Soil Types• Cultivar

Spatial Weather:• Insolation• Temperature• Precipitation

Model Output• Yield• Drought Stress • Irrigation Demand• Residual Fertilizer

GriDSSAT Website Updated Daily

http://gridssat.nsstc.uah.edu/

Week of May 29th, 2012

Comparison of the U.S. Drought Monitor to the GriDSSAT Crop Stress Index and 7-Day Cumulative Precipitation

Week of June 5th, 2012

Week of June 12th, 2012

Week of June 19th, 2012

Week of June 26th, 2012

Week of July 3rd, 2012

Week of July 10th, 2012

Analysis w/ Crop-Scape Masking

Week of August 31st, 2012

2012 Yields with Irrigation222 bu/ac

183bu/ac

173 bu/ac

119 bu/ac

45 bu/ac

Irrigation Demand is Dynamic

GriDSSAT Crop

Model

USDA NASS

CropScape Data

Watershed Irrigation

Withdrawals

Real-time Radar Derived Precipitation

NASA land surface temperatures

Satellite derived insolation Real-time Gridded Crop ModelReal-time WaSSI Model

Provide both Crop Stress & Water Stress to Stakeholders

THANK YOU!

QUESTIONS?