Photo: Orchard Mesa Research Center 08/04/2015

PROJECT PARTNERS

Dr. Perry Cabot │ Colorado State University

Photo: Orchard Mesa Research Center 03/28/2016

Colorado Mesa University Water WorkshopAgricultural Demand Management

PROJECT PARTNERS

Colorado Mesa University Water WorkshopAgricultural Demand Management

Dr. Perry Cabot │ Colorado State University

Photo: Orchard Mesa Research Center 08/06/2016Photo: Orchard Mesa Research Center 03/28/2016

Multi-Year / Multi-Site Study of Partial-Season Irrigation

Evapotranspiration RatesConserved CUForage Yields

Recovery after Stress Period

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 3

Two basic strategies to achieve agricultural demand management through “forgone

diversion”

Conservation and Efficiency

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 4

Conservation: Try to irrigate less than whole plant CU rate (lower yield but not necessarily linear with value!)

Efficiency: Try to irrigate at full plant CU rate (increase or maintain yield and profit)

ECKERT, COLOMA, CO Conservation versus Efficiency

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 5

No Change Conservation Efficiency

Consumes 29 unitsConsumes 46 units Consumes 46 units

100UNITS

100UNITS

100UNITS

20UNITS

50UNITS

Return Flows30 UNITS

58% efficiency

Non‐beneficialLosses3 UNITS

Return Flows19 UNITS

58% efficiency49

UNITS

68UNITS

90% efficiency

Water Withdrawals51 UNITS

Return Flows4 UNITS

49UNITS

53UNITS

Water Withdrawals51 UNITS

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 6

Limited: Reduce or budget water applications through a combination of practices across the whole farm water less acres, recycle, change equipment can include deficit irrigation

Deficit: Irrigate less than the full ET demand of the whole plant

Partial-Season: Cut off water mid-season Realistic only for forage crops

ECKERT, COLOMA, CODeficit, Limited and Partial-Season Irrigation

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 7

Undersander (1987) compared yield-ET relationships for hay cuttings in Bushland, TX Across the growing season – yield-ET relationship changes

depending on the cutting (time of year) Alfalfa plants, for example, use more water as it gets hotter

… but the increased water use (transpiration) doesn’t translate exactly to more biomass as it gets hotter

ECKERT, COLOMA, COPrior Research on Partial-Season Irrigation

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 8

ECKERT, COLOMA, COIrrigated Acreage - Divisions 4, 5, 6, 7

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 9

The 1929 cut‐off is June 25, 1929, the effective date of the Boulder Canyon Project Act, which became the basis for the apportionment of the lower mainstem in Arizona v. California. The 1922 cut‐off is November 24, 1922, the date that the 1922 Compact was signed.

ECKERT, COLOMA, COConsumptive Irrigation Requirement - Divisions 4, 5, 6, 7

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 10

ECKERT, COLOMA, COWSLCU Requirement - Divisions 4, 5, 6, 7

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 11

ECKERT, COLOMA, COCrop Production Functions for Alfalfa and Pasture

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 12

Crop Yield Factor(tons/ac per inch)

Crop Production(inches per ton/ac)

Study

Alfalfa 0.243 4.12 Hill, 1983Alfalfa 0.200 5.00 Wright, 1988

Grass (Pasture) 0.170 5.88 Doorenbos and Kasam, 1979Alfalfa 0.226 4.42 Doorenbos and Kasam, 1979Alfalfa 0.202 4.95 Smeal, 1991 & 1994Alfalfa 0.157 6.37 Sammis T.W. 1979 & 1981

Grass (Pasture) 0.204 4.90 A. Bowman and B. Scott, 2009

Alfalfa 0.177 5.65 T. Bauder, N. Hansen, B. Lindenmeyer, J.Bauder, and J. Brummer, 2011

Alfalfa 0.160 6.25 S. Orloff, D. Putnam, B. Hanson, and H.Carlson, 2005

ECKERT, COLOMA, COHansen (2008) – Crop Production Function

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 13

ECKERT, COLOMA, CO Putnam and Orloff (2015)5.6

6.3

7.1

8.3

10.0

12.5

16.7

25.0

50.0

Crop

 Produ

ction Functio

n (in

ch/ton

 per acre)

Recall Hansen (2008)

Takes more water in hotter months to  generate similar tonnage.  Perhaps optimal 

time for leasing?

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 15

Grand Valley and Orchard Mesa

Uncompahgre and North Fork

Southwest

Upper Gunnison

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 16

Grand Valley and Orchard Mesa

Uncompahgre and North Fork

Southwest

Upper Gunnison

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 17

ECKERT, COLOMA, COPhase II-B and II-C Western Slope Alfalfa Study Sites

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 18

ECKERT, COLOMA, COYield and Crop Production ET (alfalfa)

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 19

ECKERT, COLOMA, COYield and Crop Production ET (alfalfa)

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 20

ECKERT, COLOMA, COYield and Crop Production ET (alfalfa)

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 21

Alfalfa yields were largely positive in the final year of recovery when fields were returned to full irrigation after two seasons of partial-season irrigation Average 1st cutting yield on REF, low-risk and high-risk plots were

1.01, 1.13 and 1.30 T/ac Average 2nd cutting yield on REF, low-risk and high-risk plots were

1.17, 1.07 and 1.25 T/ac Average 3rd cutting yield on REF, low-risk and high-risk plots were

1.02, 1.07 and 1.05 T/ac

ECKERT, COLOMA, CO Alfalfa Yield Recovery Evaluations

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 22

This work supports the findings of others who reported yield recovery of alfalfa subjected to partial season water stress (Lindenmayer, 2008).

Average plot-relative yield changes from year 2 to year 3 on REF, low-risk and high-risk fields was -26.6%, 13.6% and 27.8%, respectively, for the 1st cutting.

Relative to the REF field, yield increases from the “low-risk” and “high risk” irrigation regimes exhibited probability of 7.5 and 4.2%due to chance (Student’s T-test).

ECKERT, COLOMA, COAlfalfa Yield Recovery Evaluations (cont)

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 23

ECKERT, COLOMA, COYield and Crop Production Functions (grass)

2017 Colorado Water Congress │January 25, 2017│ Denver, CO 24

ECKERT, COLOMA, CO Orloff et al. (2016) - grasses

Oxygen Deprivation. Lack of oxygen can cause death or damage. Death of fine root hairs. Fine root hairs are critical for nutrient and

water uptake … damaged during waterlogging. Root Pruning. Saturated sub-surface layers can damage roots below

that level … also may deposits salts when capillary action recedes. Micronutrient availability. Low oxygen conditions can lead to iron (Fe)

and other micronutrients unavailable for plant growth Disease and pests. Phytophthora, stem nematodes can weaken alfalfa

Factors affecting Recovery

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 26

Nutrient carryover. Reduced irrigation prevents N losses Nodules. Rhizobium nodules are also weakened under flooded

conditions, resulting in reduced nitrogen fixation.

Factors affecting Recovery (cont)

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 27

Average N Levels (0-12”) – 03/22/2016

Nitrate-N (ppm) Yield (T/ac) RFVREF 14.0 1.29 167SA2-BW 14.3 0.88 189SA2 19.6 1.20 174

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 28

Total Nonstructural Carbohydrate (TNC). Plants exposed to prolonged periods of drought or drought … may

have rapid initial regrowth upon alleviation of these stresses because high amounts of total nonstructural carbohydrates (e.g., glucose, fructose, sucrose) may have accumulated in their storage organs during stress (Busso, Richards and Chatterton, 1989)

Factors affecting Recovery (cont)

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 29

Forage yields Alfalfa exhibits better yields during first, second cuttings Significant reductions during stress period (Jones, Cabot, Brummer) Carryover effects depend on soil and plant conditions (e.g, alfalfa

with deep roots versus grasses with shallow roots)

Water Use Efficiency (WUE) Lower WUE as plant uses more water to cool itself in summer

Forage quality Modest gains resulting from reduced irrigation (Jones, 2016)

ECKERT, COLOMA, COComments on Partial-Season Irrigation in Colorado

Multi-Spectral Handheld Radiometer (MSR5) used to determine spectral signature of plants (NDVI)

MSR5 measures wavebands centered at blue (485 nm), green (560 nm), red (660 nm), near infrared (NIR, 830 nm), and short-wave infrared (SWIR, 1650 nm) similar to Landsat Thematic Mapper 5 satellite (ground-truth)

ECKERT, COLOMA, CORemote Sensing / Radiometer MeasurementsLANDSAT 7 / 8

Colorado Mesa University Water Workshop │ February 20, 2018 │ Grand Junction, CO 31

End