deficit irrigation: why alfalfa is the best crop to have ... · world alfalfa congress-argentina...

World Alfalfa Congress-Argentina 2018

Deficit Irrigation: Why Alfalfa is the Best Crop

to Have in a Drought

Daniel H. Putnam

Collaborators: Ian Ray (NMSU): Mike Ottman (Univ. Arizona); UC: James Radawich; Ali Montazar, Khaled Bali, Umair Gull

University of California, Davis [email protected]

http://alfalfa.ucdavis.edu

Drip irrigated alfalfa field, California

mailto:[email protected]

http://alfalfa.ucdavis.edu/


Major Points

Alfalfa (lucerne) is a major water user in irrigated regions

Alfalfa exhibits a high degree of flexibility during low water years

Sustainable forage production during droughts


US – Irrigated Alfalfa Approx. 50% of US Production


Water Use by California Crops (4-Year Ave. 2006-2009)

0 1000 2000 3000 4000 5000 6000 7000

Potatoes

Safflower

Tomato Fresh

Sugarbeet

Dry Beans

Cucurbits

Onion & Garlic

Tomato Processing

Cotton

Grain

Truck Crops

Citrus & Subtropical

Other Field

Corn

Rice

Vineyard

Other deciduous

Pasture

Almonds & Pistachios

Alfalfa

Annual Applied Water (Acre Feet x 1,000)

16 %


Rainfed vs. Irrigated

Major difference is ‘time’ and ‘space’

Storage vs. ‘In Season’

Rain & Snow

Reservoirs Snowpack Groundwater

In-season Soil Storage Soil Storage In-season

Hay Production, November, 2018, Davis,CA

Rain & Snow


NOTE: Lack of high rainfall during

growing season is a major advantage of irrigated regions

High quality, high yields

Hay Production, December, Blythe, CA


5-Year California Drought


Lake Shasta (CA)


2017 (January)


November, 2017


May, 2018


November, 2018


2018


Groundwater Challenge in Aquifers

from

: Lest

er

Snow

, CA W

ate

r Foundation

Xiao et al. Apr. 2017


Impetus: Periodic droughts – water supply

limitations

Water transfers to other uses

– Competing crops

– Cities

– Environmental (regulatory)

Irrigation a major limiting factor for yield

– Distribution uniformity, timing

Need for highly efficient systems


Field Experiments:

1980s through 2018

What are strategies for deficit irrigation?

Are there varieties better suited to water deficits?


ETc – Davis, CA

990 mm/year

Ave. k = 0.86


Irrigation Treatments

100% of ETc (guided by Kc) Applied

75% of ETc (full, then sudden cutoff at 75% of seasonal ETc) - July

75% of ETc (fully irrigated to mid-season, then 50% of ETc )

50% of ETc (fully irrigated to mid-season, then cutoff) - June


Irrigation Treatments

(harvests)

100%

75%

50%


Yield Results


Yield Pattern


Water Productivity & ET y = 0.0008x

2 - 0.0169x + 0.1863

R2 = 0.9029

y = -0.1912x2 + 3.1543x + 3.9386

R2 = 0.9878

0

2

4

6

8

10

12

14

16

18

20

MAR

APRM

AYJU

NJU

LAUG

SEPO

CT

ET

(in

ch

es p

er

mo

nth

)

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

WU

E (

ton

s p

er

acre

/in

ch

es o

f w

ate

r)

Water Use (ET)

Water Use Efficiency


Yields-Cumulative (Mg/ha)

Variety 50% Cutoff 75% Continuous 75% Cutoff Full

NM14GTAF 54.9 55.6 65.0 65.4

AFX149092 54.9 60.0 60.0 64.4

CUF 101 51.2 56.0 57.1 58.9

NM14ALWLHQ 52.6 57.0 60.6 58.5

NM14BM1008251 49.4 52.6 51.9 58.1

AFX148091 52.3 57.4 59.3 57.8

SW10 54.6 54.4 62.8 56.6

S8421S 54.0 56.3 58.7 56.5

Artesian Sunrise 45.5 52.4 49.8 54.5

NM14MLLS2 47.9 47.7 56.4 53.0

NM14MALHS3 47.0 50.9 49.5 52.1

HybriForce 2600 44.6 49.1 52.3 49.2

NuMex Bill Melton 49.9 50.6 51.2 48.7

NM14BMHS1 47.8 47.5 50.3 48.4

R510Hg812dt 39.1 42.0 46.6 47.2

Mean 49.7 52.6 55.4 55.3

Percent of Full 89.9% 95.2% 100.2% 100.0%

LSD

C.V.

Mg ha-1

Variety response to irrigation treatmment (Cumulative

total 2015-2017).Irrigation Treatment

12.41

7.70%


End of trial

Full Irrigation (100% Seasonal

ET)

75% (Cutoff)

75% (Continuous Deficit) 50% (Cutoff)

(Oct. 16, 2017 Davis, CA)


What traits may be important?

High overall yields under full irrigation

Early season yields

Stand Survival under drought

Deep roots to access deep moisture

‘Shutting down’ during drought (even with moisture)


Kearney Trial (Fresno)

100% ET Flood

100% ET drip

50% ET drip sudden cutoff

75% ET drip season-long deficit

75% ET drip sudden cutoff

border

border 1 2 3 4 5 5 4 3 2 1 1 5 3 4 2 2 3 5 4 1Fert.

Exp.

Fert.

Exp.

Fert.

Exp.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

<--------------------------------------------------------------------------------------------------590'------------------------------------------------------------------------------------------->

Block I Block II Block III Block IV

Experiment I Experiment II

Tule System


77%


Kearney Results (Year 1)


Thermal Imaging -


Results of controlled trials Regulated deficit irrigation highly

feasible with alfalfa

‘Sudden cutoff’ superior to gradual deficits (water fully, then stop)

Variety x irrigation interaction not significant in Davis experiment

Yield losses under deficits

– Compensation for water transfer?


Alfalfa – Best Crop for a Drought

Deep Rootedness

Perennial

High Yields

High Harvest Index

High Water Productivity

Seasonal Yield Patterns

Salt Tolerance

Flexibility…!

http://ucanr.edu/blogs/Alfalfa/blogfiles/29610_original.jpg


Many Thanks!


Many thanks!

Wagner farm, WA state, photo

deficit irrigation: why alfalfa is the best crop to have ... · world alfalfa congress-argentina...

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