rudnick 2017 water seminar-3

Advancements in Irrigation Technology and their Impact on Water Management

Spring 2017 Water Seminar Series Lincoln, NEMarch 15, 2017

Daran R. Rudnick, Ph.D.Assistant Professor: Irrigation Specialist

Department of Biological Systems EngineeringWest Central Research and Extension Center

University of Nebraska-LincolnPhone: (308) 696-6709, Email: [email protected]

Personal Background

• Hometown: South Sioux City, Nebraska

• Education:

• B.S. Biological Systems Engineering, UNL, 2011

• M.S. Agricultural and Biological Systems Engineering, UNL, 2013

• Ph.D. Agricultural and Biological Systems Engineering, UNL, 2015

• Appointment:

• Irrigation Management Specialist (50% Research/ 50% Extension)

HometownSouth Sioux City, NE

WCRECNorth Platte, NE

UNLLincoln, NE

Research Team• Turner Dorr: Irrigation Research

Technologist II

• Tsz Him Lo: PhD Graduate Research Assistant

• Jasreman Singh: MS Graduate Research Assistant

• Jacob Nickel: Irrigation Research Technician

• Bridgett Dorr: Program Assistant

Himmy Lo Jasreman Singh

Turner Dorr& Bridgett Dorr

AcknowledgementThis study is based upon work that was jointly supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture (USDA-NIFA) under award numbers 2016-68007-25066 and 2016-68008-25078, United States Geological Survey Section 104B under award number G16AP00068, and the Daugherty Water for Food Global Institute under award number 01117420. Also thankful for industry support through providing equipment and services.

Why do we Irrigate???

When precipitation and stored soil water in the crop root zone are insufficient to meet crop evapotranspiration (ET) demand, irrigation is required.

Insufficient Irrigation can reduce:• Total Biomass

• Grain Yield

• Grain Quality

• Net Return ($ per ha)

Excessive irrigation can result in:• Runoff

• Soil Erosion

• Deep Percolation of Water (and Nutrients)

• Environmental Degradation

• Anaerobic Soil Conditions (Yield Penalty)

• Increased Pumping Cost (i.e., energy cost)

Source: Irmak (2009), Rudnick and Irmak (2015)

Nebraska Precipitation

Precipitation, mm

100 - 200

200 - 250

250 - 300

300 - 350

350 - 400

400 - 450

450 - 500

500 - 550

550 - 650

> 650

2000 2005

2010 Lng-Term

Avg.

Precipitation Increases West to East Irrigation Increases East to West

Source: Rudnick et al. (2015)

Nebraska: Density of Registered Irrigation Wells

2007

Nebraska: Nitrate Groundwater Contamination

Recorded concentration of nitrate (NO3) in irrigation wells from 1974 to 2012 (Quality-Assessed Agrichemical Database for Nebraska Groundwater, 2013).

EPA Maximum Contamination Level (MCL) is 10 ppm

Effects of Over- or Under Irrigating

Impact of Water Stress

Full Irrigation Deficit Irrigation Rainfed

Source: Jeff Golus

Runoff and Soil ErosionSource: Pioneer.com

High Soil Water Content

Crop Water Requirements

Depends on:

• Crop Type & Variety

• Growth Stage

• Soil Water & Nutrient Availability

• Soil Physical & Chemical Properties

• Micrometeorological Conditions

• Among others

Corn crop water use or daily evapotranspiration (ET) from a well-watered crop. The smooth line (A) depicts long-term daily ET and the jagged line (B) depicts daily ET for an individual year. (Taken from UNL NebGuide G1850, http://extensionpublications.unl.edu/assets/pdf/g1850.pdf).

Corn Water Use (inch per day)

Water Demand from Various Sectors

Climate

Industry

Groundwater Declines in the Ogallala Aquifer

• Water level changes in the High Plains Aquifer, pre-development through 2007

• Groundwater is connected to surface water

• Reduction in groundwater levels can limit water available for irrigation

• Consequently, restrictions have been enforced in areas to sustain and/or extend the useable life of the aquifer for future generations

Source: McGuire (2009) as modified from Lowry et al. (1967); Luckey et al.

(1981); Gutentag et al. (1984); and Burbach (2007). Taken from Konikow (2013)

• Nebraska Natural Resource Districts (NRDs) water management regulations can include:

• Allocating groundwater

• Augmenting surface water

• Requiring flow meters

• Instituting well drilling moratoriums

• Requiring water use reports

• Restricting expansion of irrigated acres

Nebraska Natural Resource DistrictsAllocations Updated February 2014

• Upper Niobrara-White NRD

• 54” per 4 years

• North Platte NRD


• & Pumpkin Creek = 36” per 3 years

• South Platte NRD

• 42 to 54” per 3 years (by subarea)

• Upper Republican NRD


• Middle Republican NRD


• Twin Platte NRD

• No allocation

• Upper Loup NRD

• No allocation

• Middle Niobrara NRD

• No allocation

Conventional Sprinkler IrrigationApplying a uniform depth of water per area through the irrigation system to meet average crop water demands of a field.

Source: pintrest.com

Center Pivot (1960’s)

Irrigation Distribution Uniformity1.

2.4.

3.Source: ASAE (2003)

Source: Chuck Burr

Mobile Drip Irrigation (MDI)

System Types

• Sprinkler (Senninger IWob) & MDI

Irrigation Levels

• Full, Deficit, & Rainfed

Residue Levels

• No-Removal & Baling

MDI Research• Preliminary Results

• Similar grain yields and kernel weights across system types

• Future Research Efforts

• Crop Water Use (ET)

• Long-term trends in production & water use

Variable Rate IrrigationSystem Description

Variable Rate Irrigation (VRI)

Applying variable depths or rates of water through an irrigation system to meet differences in crop water demands, soil conditions, and/or other constraints.

0.60 – 0.90 m

0.30 – 0.60 m

0 – 0.30 m

Available Water Capacity, mm

Source: Rudnick and Irmak (2014a, 2014b)

Types of VRI

Depending on system and controller VRI can be managed in sectors, bank of sprinklers, or individual sprinklers.

Fixed Zone Control Irregular Zone ControlSector/Speed Control

Speed/Sector Control

• Changes end tower speed at specified angular positions

• Modifies application depth in sectors of the circular pass

• Alters application duration but not application intensity

• Does not affect sprinklers, system curve, or pump performance curve

Sector/Speed Control

15 mm 20 mm25 mmapplication

intensity

time

at a given radius

from pivot point

Sprinkler Control• Changes discharge of individual or banks of

sprinklers

• Relies on valves directly upstream from sprinkler

• Changes in sprinkler discharge achieved by pulsing

• Turns off a sprinkler for a fraction of a cycle

• Optimizes timing to minimize flow rate oscillations

• Modifies application depth in more flexibly shaped zones as compared to sector control

Solenoid Valve

Pressure Regulator

Sprinkler

Video of Pulsing Sprinklers

Sprinkler Control• Individual or groups of sprinklers (i.e.,

banks of sprinklers)

• Changes in application depth accommodated by• Speed of pivot

• Pulsing of sprinklers

• Management zone must be greater than sprinkler throw diameter (consider sprinkler overlap!). More zones = more work!

Fixed Zone Control

15 mm

20 mm

25 mmapplicationintensity

time

sprinklers at a given

radius from pivot point

Irregular Zone Control

Example: Fixed Zone Pivot at Big Springs, NE

Span 1 - 6: On

Span 7-8: Off

Primary Valve

Secondary ValvesSmallest Zone1ᵒ ChangeSpan Control

Controller

Example: Sprinkler Controlled Pivot at Grant, NE

Variable Frequency Drive (VFD)

• VFD speeds up or slows down the pump motor to reach a desired operating pressure or flow rate

• Adopting VFD will depend on flow rate & pressure changes within the system (is it economical?)

• High or premium efficiency motors are often required

Irrigation Management Technology Benefits & Challenges

Irrigation and N Fertilizer Management

A primary research and production goal is to further improve irrigation and nitrogen use efficiency to enhance economic return as well as prevent environmental degradation. Addressing the following will aid in this effort.

• Reduce uncertainty in measuring/estimating crop water and nitrogen requirements

• Account for spatial and temporal differences in crop water and nitrogen demand

• Accurately apply inputs to minimize losses• Irrigation: runoff, percolation, evaporation

• Nitrogen (depends on N type): volatilization, leaching, de-nitrification, runoff

• Concurrently manage irrigation and nitrogen fertilizer

• Fertigation is a step forward in this direction

Some Useful Information for Irrigation ManagementInformation (Source):

• Historical Records (Yield data, compaction issues, etc.)

• Soil Properties (NRCS soil surveys, ECa mapping)

• Topography (DEM-digital elevation maps via survey, LiDar, etc.)

• Field Conditions (Residue level, pest pressure, nutrient availability, etc.)

• Visual Observations (Drainage ways, streams, roads, etc.)

• Soil Water Status (Soil water sensors)

• Evaporative Demand (Climatic variables via weather station)

• Crop Water Stress (Thermal sensors)

• Crop Growth and Condition (Canopy reflectance, visual imagery, and crop models)

• Remote Access to System (Telemetry)

• System Performance (Pressure transducers, telemetry, etc.)

Management Zone Delineation

• Apparent Electrical Conductivity (ECa)• Easy to measure and relatively low cost

• Indirect indicator of important soil physical and chemical characteristics

• Commonly used for VRI application

• Some Factors Impacting ECa• Clay content and mineralogy

• Soil salinity

• Cation exchange capacity

• Soil pore size distribution

• Temperature

• Organic matter content

• Soil water content

Source: Rudnick and Irmak (2014)

ECa Response Curve vs. Rooting Depth

Source: Irmak and Rudnick, 2014

Crop Type Total RootingDepth (ft)

Effective RootingDepth (ft)

Alfalfa 8 – 12 4 – 5

Corn 5 – 6 3 – 4

Sorghum 6 – 7 3 – 4

Soybean 5 – 6 2 – 3

Winter Wheat 4 – 5 2 – 3

Mature Growth Stage, under well drained, deep silt loam soils

ECa vs. Soil Hydraulic Properties

Sources: Rudnick and Irmak (2014)

𝐴𝑊𝐻𝐶 = 𝐹𝐶 −𝑊𝑃 × 𝑅𝐷

AWHC: Available Water Holding Capacity

FC: Field Capacity

WP: Wilting Point

RD: Rooting Depth

Soil Type Available Water (in/ft)

Silt Loam 2.5

Sandy Clay Loam 2.0

Silty Clay Loam 2.0

Silty Clay 1.6

Sandy Loam 1.4

Loamy Sand 1.1

Fine Sand 1.0

Available Water

Diagram for Irrigation using Soil Water Sensors

Management Zone

Water Freely Drains

Crop Water Stress Zone

Water NotAvailable to the Crop

Dry Soil

Saturation

Field Capacity

MAD = Trigger PointLatest Start Date

Wilting Point

Irrigation

Soil WaterSensor

Some In-Situ Soil Water Sensor Companies

Soil Water Sensors & ETgage

Campbell Scientific CS616SWC

Campbell Scientific CS655SWC, Temp, & EC

MPS-2 or MPS-6 5TE EC-5

SWP & Temp SWC, Temp, & EC SWC

---------- Decagon Devices ----------

Stevens Hydra Probe IISWC, Temp, & EC

Acclima True TDRSWC, Temp, & EC

Irrometer WatermarkSWP

Irrometer TensiometerSWP

ETgage (Atmometer)Reference ET

Legend:SWP: Soil Water PotentialSWC: Soil Water ContentTemp: Soil TemperatureEC: Bulk Electrical Conductivity

In-Field Sensor Evaluation

Sensors:

• AquaSpy

• AquaCheck

• John Deere Field Connect

• Hortau

• Decagon 5TE, EC5, MPS-2, MPS-6

• Stevens Hydraprobe

• Acclima TDR315

• Campbell Scientific CS616 & CS655

• CPN Neutron Gauge

• Irrometer Watermark, Tensiometer

Year: 2016

Location: North Platte, NE

Crop Type: Soybean

Loam Soil little salinity

In-Field Sensor Performance

• All Sensors tended to over-estimate

θv (m3 m-3) Combined Depths

Sensor MD SDD RMSD

TDR315 0.047 0.019 0.050

CS655 0.056 0.055 0.078

HydraProbe2 0.095 0.036 0.102

5TE 0.036 0.015 0.039

EC5 0.048 0.026 0.054

CS616 0.149 0.051 0.157

Field Connect* 0.079 0.027 0.083

AquaCheck* 0.162 0.017 0.163

Evaluation of Calibration Techniques

• Offset Calibration

• 2 Point Calibration

• Regression Fitting

• Retention Fitting

• Laboratory Calibration

Offset Example:• Take one accurate

measurement in-season

• Offset all other points

• Assumption: Regression response is linear with a slope of 1

Well-Performing Offset Calibration

In-Field Regression Calibrations

Regression Response

• 5 Linear and 19 Quadratic

Linear Responses

• Estimate of intercept > zero

• Linear Coefficient < one

• Sensors are more sensitive than reference

Quadratic Responses

• Sensitivity generally increased with θv within the observed θv

range

Laboratory Calibrations

• Most sensors tended to over-estimate θv in the lower observed θv

range.

• Variability in sensor performance was observed between lab and field calibrations.

Laboratory Calibration Techniques

Repacked versus Intact Soil Cores

• Different drying trends

• Repacked slightly underestimated water content

Statewide Soil Experiment

• Five Soil Types

• Four Salinity Levels

• Two Sensors Evaluated• TDR 315 & CS655

weight % of soil solids

weight % of mineral fraction g cm-3

SoilOrganic Matter

Sand Silt ClayTarget Bulk

Density

V 0.2 (0.0) 88 (1) 7 (1) 5 (1) 1.6

C 2.1 (0.1) 55 (3) 23 (3) 22 (0) 1.3

K 2.6 (0.1) 35 (2) 35 (3) 30 (2) 1.3

H 2.4 (0.1) 14 (3) 40 (5) 46 (2) 1.4

W 2.5 (0.1) 8 (4) 42 (1) 49 (4) 1.4

Instrumentation for VRI Research

Research Questions

• How to collect and analyze different information of various spatiotemporal resolutions to inform VRI scheduling and prescription generation?

• Would VRI affect nitrogen management? If so, how can irrigation and nitrogen management be optimized simultaneously?

Year 1 Management Zones and Treatments

• Two management zones—one consisting of gravelly soils and another consisting of non-gravelly soils

• Zones were delineated using ECa, assuming lower ECa represents gravelly soils

• Full irrigation (F): attempt to eliminate any water stress

• Conventional (C): uniform irrigation based on the non-gravelly soil

• Deficit irrigation (D): allow water stress during less sensitive growth stages

• Non-irrigated (R): no irrigation

Sprinkler Controlled Pivot at Brule, NE

Point-Based Water Status DataAquaCheckmultisensorcapacitance

probe

neutron moisture meter

wireless infrared

thermometer

scaled frequency

units

0

50

100

150

200

250

300

D F C R D F R

Tota

l Wat

er

in 0

-0.9

m

June 23rd, 2016

0-0.3 m

0.3-0.6 m

0.6-0.9 m

non-gravellygravelly

irrigation:

soil:

0

50

100

150

200

250

300

D F C R D F R

Tota

l Wat

er

in 0

-0.9

m

October 3rd, 2016

0-0.3 m

0.3-0.6 m

0.6-0.9 m

non-gravellygravelly

irrigation:

soil:

0

5

10

15

20

25

30

35

0:00 8:00 16:00 0:00 8:00 16:00 0:00

Surf

ace

Te

mp

era

ture

(°C

)

Time

fully irrigated

deficit irrigated

Visible Imaging

deficit irrigatedfully

irrigated

deficit irrigatedfully

irrigated

August 1st, 2016 (silking) September 26th, 2016 (30% milk line)

Thermal Infrared Imaging aerial image taken by AirScoutground-based images taken using FLIR E60

non-irrigated

fully irrigated

Radiometric Temperature

Instruments• Infrared Thermometers (IRTs)

• Aerial Thermal Imagery (Airscout)

Observations

• Airscout observed smaller ranges in Temp as well as lower Temp values.

AirScout thermal (left) and visible (right) image of the Brule site on 9/26/2016; the 12 monitoring locations are marked and labeled, and the rainbow color scale from blue to

red in the thermal image denotes radiometric temperatures from low to high.

Collaborative VRI Research

• Irrigation Management using Remote Sensing

• Research project initiated at UNL Brule Water Laboratory in 2016

• Collaboration:• Burdette Barker

• PhD Graduate Student

• UNL Biological Systems Engineering

• Derek Heeren• Assistant Professor: Irrigation Engineer

• UNL Biological Systems Engineering

• Christopher Neale• Director of Research

• Water for Food Daugherty Global Institute

WCREC Research Site: Brule, NE

Elevation (m)

Topographic Map

University of Nebraska-LincolnWest Central Research and Extension Center

Brule Water Laboratory near Brule, NE

0 - 2

2 - 4

4 - 6

6 - 8

8 - 10

10 - 12

Slope (%)Soft Edge

1073 - 1075

1070 - 1073

1067 - 1070

1064 - 1067

1061 - 1064

1058 - 1061

1055 - 1058

1052 - 1055

1050 - 1052

±

Irrigation Management Using Remote Sensing

Multispectral Imagery (Spatial –Low Temporal)

Soils Map

Weather Data (High Temporal)

Previous Irrigation Maps

New Irrigation Prescription and Schedule

RS – Based Hybrid Water

Balance Model

Neale, C.M.U., Geli, H.M.E., Kustas, W.P., Alfieri, J.G., Gowda, P.H., Evett, S.R., Prueger, J.H., Hipps, L.E., Dulaney, W.P., Chavez, J.L., French, A.N., and Howell, T.A. (2012). Soil water content estimation using a remote sensing based hybrid evapotranspiration modeling approach. Advances in Water Resources, 50, 152-161.

VRI System at Research Center

Experimental Layout at WCREC

• Treatments

• RS-based VRI management

• Conventional or “uniform” management using water balance

• Blocked by available water capacity zones (determined from neutron probe and soil series)

• Continuous maize crop ~49 ha

• Individual sprinkler zone control VRI Aerial Image Source: USDA-FSA (2014). USDA-FSA-APFO NAIP MrSID

Mosaic for Keith County, Nebraska. U.S. Department of Agriculture, Aerial Photography Field Office, National Agricultural Imagery Program.

Preliminary Results WCRECIrrigation Depth:• Conventional: 324 mm

• VRI w/ Remote Sensing: 342 mm

Variability in seasonal irrigation amount.

Fertigation ResearchDemonstrate the potential for improving nitrogen use efficiency (NUE) while optimizing profitability through the use of canopy reflectance and crop N modeling techniques.

• Collaboration:• Brian Krienke

• Suat Irmak

• Richard Ferguson

• Tim Shaver

• Charles Shapiro

• Keith Glewen

• Locations:• West Central Research and Extension Center, North Platte, NE, USA

• South Central Agricultural Laboratory, Clay Center, NE, USA

Variable Rate Fertigation (VRF)

Applying variable amounts or rates of fertilizer through an irrigation distribution system to meet spatial and temporal differences in crop nutrient demands, soil conditions, and/or other constraints.

VRF Scenarios:

• VRF with variable rate fertigation pump• Uniform Irrigation and Variable Fertilizer

• Variable Irrigation and Uniform Fertilizer

• VRF with constant rate fertigation pump• Use VRI technology with uniform fertilizer speed

Thank You!

The mention of trade names or commercial products in and during this presentation does not constitute an endorsement or recommendation for use by the University of Nebraska-Lincoln or the author.