Design of Resilient Agro-Ecosystems | Trenton Franz

Design of resilient agro-ecosystems

Trenton FranzHydrogeophysicist and Asst. Professor

Acknowledgements:

Justin Gibson (PhD), Catie Finkenbiner (MS), William Avery (MS), Matt Russell

(Undergrad), Tiejun Wang (Research Scientist), Jacob Fritton (TNC)

September 19th, 2017

• Long-term Goal: • Build a decision support tool that serves producers in western Nebraska and can

be scalable and transferable to expand to the whole US irrigated regions

The Big Picture



• Embrace the complex social-ecological system of irrigation

agriculture in Western Nebraska• Physically based surface and groundwater models will only take us so far

• Design conservation efforts to be simple and economically sustainable for

producers

• How do we get to switch point where it is more costly to not use conservation

strategies?

The Big Picture



• Embrace the complex social-ecological system of irrigation

agriculture in Western Nebraska• Physically based surface and groundwater models will only take us so far

• Design conservation efforts to be simple and economically sustainable for

producers

• How do we get to switch point where it is more costly to not use conservation

strategies?

• Ecological theory tells us that complex patterns emerge from

simple local interactions• What are these local interactions?

• Are we able to describe their rules mathematically?

• How do we invest in technology and human capital to change these rules in

order to achieve a more desirable emergent pattern?

The Big Picture

Prof. Trenton Franz

2004-BS in Civil Engineering, University of Wyoming

2005-MS in Civil Engineering, University of Wyoming

2001-2004-Starting center for UW football team

2007-MS in Civil and Environmental Engineering, Princeton University

2011-PhD in Civil and Environmental Engineering, Princeton University

2011-2013-Postdoctoral researcher in Hydrology and Water Resources,

University of Arizona

Sept. 2013- Asst. Professor University of Nebraska-Lincoln, Faculty Fellow of

Daugherty Water for Food Global Institute

60% Research, 40% Teaching

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What do I study?

Ecology/Agronomy:

Mechanisms,

Processes

Hydrology:

Conservation

Equations

Geophysics:Measurements,

Tools

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Our goal is to monitor and model the flow of water through natural and

human dominated ecosystems in order to understand how ecosystems

function and how to utilize water more efficiently for food production.

Bring together academic, industry, and stakeholders

to design a low cost, scientifically accurate, and

functional monitoring system

Hydrogeophysics Science Lab Mission

Water for Food Support/Impacts

• Hired as part of Water Cluster in 2013

• Direct support of salary and startup

• Supported 1 MS and 1 PhD through DWFI grant program

• Co-PI on 300k NSF Water literacy IUSE grant

• Co-developed SCIL 109 Water and Society course (Spring 2017)

• Organized session at 2016 Water for Food Conference

• Contribution to various grants, matching, conference presentations

and publications

DWFI Supported Students

2014-2016: William Avery, University of Nebraska-Lincoln, School of Natural Resources, MS

Primary Advisor. Awarded 1-year internship with FAO/IAEA in Vienna, Austria.

2016-2019: Justin Gibson, University of Nebraska-Lincoln, School of Natural Resources, PhD

Primary Advisor. Awarded 3-month internship with The Climate Corporation (Spring 2017).

Example of emergent properties in complex

systems

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Properties of Dryland Ecosystems

Soil

Climate Topography

Vegetation

Complex system,

stochastic and

nonlinear properties

System dynamics

governed by strength of

interactions

Strength of interactions

are dependent on

spatial and temporal

scale

Vegetation pattern is an indicator of interactions

Tiger Bush Labyrinths Spots Gaps

Borgogno et al. 2009

Emergent Property of Ecosystem

Hypothesis: Length scales of competition and facilitation for resources

(light, water, nutrients)

What is controlling pattern formation?

Borgogno et al. 2009

Key resource in drylands is plant available moisture!

What do we know about the long-term

sustainability of the HPA?

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14Butler et al. 2016

15Butler et al. 2016

• Each aquifer has an annual water use limit that

leads to ~0 water level decline

• Need long-term well monitoring program to

determine sustainable withdrawals

• Gives you an annual total volume of water target

• Furthermore, you can break volume down by

irrigated acres and irrigation depth!

Other than reducing irrigated acres how do

we get to this “sustainable” volume of water?

How do we positively change day-to-day

local interactions of irrigation depth?

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Irrigation In Central Nebraska

17K. Gibson et al. 2016, in review, Agricultural Water Management

~1400 maize fields over 9 yrs

18Gibson et al. 2016, in review, Agricultural Water Management


19Gibson et al. 2016, in review, Agricultural Water Management


• Rainfall and irrigation depths are not surprisingly

interconnected

• Only 45% of irrigation depths explained by soil and

plant biophysical needs

• Producers are consistent water users year to year

and influenced by what their neighbors are doing

What are we finding from the Western

Nebraska Irrigation Project (2014-2016)?

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1. Growing season rainfall varies considerably across WNIP study area, affecting day to day

management decisions

Need for spatially distributed network (~ 1 gage per 4 sq. miles)

From Gibson et al. 2017 HESS

2. Because of location next to front range, about 70% of rain events occur at night

Lag in rainfall to time to shutoff costs producers, money, water, energy, travel time.

At ~$10/hr energy costs and water use may be significant

Distribution of rainfall over the hour of day for 2015 growing season (April-September)

for WNIP project John Deere weather station. Yellow rectangle represent light hours and

blue rectangles represent dark periods.

3. Producers tend to hit irrigation plus precipitation target of 700 mm/yr (28 inches)

Better local realtime rainfall data + pivot telemetry can lead to actionable decisions and

reduced pumping


4. Crop model with 4 different irrigation triggers indicates pumping savings with no impacts on yield

up to 100 mm/yr of reduced pumping with <3% yield losses


5. Preliminary results of WNIP cost share indicate realized reductions in pumping

~100 mm/yr (2014-2016) vs. (2009-2013) for 1300 acres in western corner according to NRD

flow meters

Anticipate similar savings across other NRDs over several years and continued

support of extension/liason services (J. Fritton TNC)

Preliminary results from TNC WNIP, based on South Platte NRD database and Brule

AWDN gage

Where are we going with Western Nebraska

Irrigation Project (2017-2019)?

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Next generation of low cost

met. and crop water

demand sensors

Observations (5 min):

• rain gauge (disdrometer)

• leaf wetness

• shortwave and longwave up and

down

• 6-band spectrometer

• air temp

• humidity

• pressure

• GPS

• digital level and compass

• plug for peripherals, i.e. camera, soil

moisture, pressure

• Telemetry, Cell, Wifi, or Bluetooth

• Hourly updates

• Solar powered

• Cost: ~$600 hardware +

~$50/month telemetry, sotfware, API

http://arable.com/

1. A smart rainfall network

Network of Arable Stations

Data view as of July 2, 2017

30 km

Network of Stations

2017 Rainfall Data Totals

Support of Precision Agriculture

How can we best use CRNP to support precision

agriculture?

Can the technology provide cost effective spatial

information to make a management decision?

In review, Precision Agriculture

• Paulman Farms located near Sutherland, NE

• Center-pivot irrigated corn

Hydrogeophysical Mapping

SWC (cm3cm-3)

03/25/2015 05/18/2015

05/26/2015 06/08/2015

06/10/2015 06/15/2015

02/24/2016 05/09/2016

05/11/2016 06/06/2016

Soil Sampling

• Collected 31 undisturbed soil cores at 20cm depth

• Sample locations chosen based on SSURGO soil

boundaries, EOFs, and EM surveys

• Samples were placed in a cooler in the field and

then stored in a freezer at the lab

SSURGO EOF1 EOF2 ECa

Spatial Products Useful for Irrigators

a) SWC (cm3cm-3)

at FC

R2 = 0.697

RMSE: 0.043

b) SWC (cm3cm-3)

at FC

R2 = 0.321

RMSE: 0.014

WP

c) AWC (cm3cm-3)

R2 = 0.677

RMSE: 0.039

Precision Agriculture Summary

1. CRNP mapping + EOF is best environmental covariate

predictor of lab derived soil properties

2. Economically viable (?) for high value crops or areas with

severe water allocation

Take home messages

1. Society cares about past, present and future water fluxes (i.e. recharge,

runoff, evapotranspiration, irrigation)

2. Strong extension/liason program with introduction of irrigation technology

shows irrigation savings of ~100 mm from 2014-2016 WNIP numbers

3. Targeting producers with distribution of smart, localized, and easy to use

rainfall network (Arable Marks) to get better P+I numbers in 2017+. Hope

to reduce pumping, reduce energy use, maintain yields across study area

(affect local decisions to change emergent patterns)

4. Using mobile CRNP to get better spatial soil properties for coupling with

precision ag. technology

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