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
World Alfalfa Congress-Argentina 2018
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
World Alfalfa Congress-Argentina 2018
US – Irrigated Alfalfa Approx. 50% of US Production
World Alfalfa Congress-Argentina 2018
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 %
World Alfalfa Congress-Argentina 2018
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
World Alfalfa Congress-Argentina 2018
NOTE: Lack of high rainfall during
growing season is a major advantage of irrigated regions
High quality, high yields
Hay Production, December, Blythe, CA
World Alfalfa Congress-Argentina 2018
5-Year California Drought
World Alfalfa Congress-Argentina 2018
Lake Shasta (CA)
World Alfalfa Congress-Argentina 2018
2017 (January)
World Alfalfa Congress-Argentina 2018
November, 2017
World Alfalfa Congress-Argentina 2018
May, 2018
World Alfalfa Congress-Argentina 2018
November, 2018
World Alfalfa Congress-Argentina 2018
2018
World Alfalfa Congress-Argentina 2018
Groundwater Challenge in Aquifers
from
: Lest
er
Snow
, CA W
ate
r Foundation
Xiao et al. Apr. 2017
World Alfalfa Congress-Argentina 2018
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
World Alfalfa Congress-Argentina 2018
Field Experiments:
1980s through 2018
What are strategies for deficit irrigation?
Are there varieties better suited to water deficits?
World Alfalfa Congress-Argentina 2018
ETc – Davis, CA
990 mm/year
Ave. k = 0.86
World Alfalfa Congress-Argentina 2018
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
World Alfalfa Congress-Argentina 2018
Irrigation Treatments
(harvests)
100%
75%
50%
World Alfalfa Congress-Argentina 2018
Yield Results
World Alfalfa Congress-Argentina 2018
Yield Pattern
World Alfalfa Congress-Argentina 2018
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
World Alfalfa Congress-Argentina 2018
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%
World Alfalfa Congress-Argentina 2018
End of trial
Full Irrigation (100% Seasonal
ET)
75% (Cutoff)
75% (Continuous Deficit) 50% (Cutoff)
(Oct. 16, 2017 Davis, CA)
World Alfalfa Congress-Argentina 2018
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)
World Alfalfa Congress-Argentina 2018
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
World Alfalfa Congress-Argentina 2018
77%
World Alfalfa Congress-Argentina 2018
Kearney Results (Year 1)
World Alfalfa Congress-Argentina 2018
Thermal Imaging -
World Alfalfa Congress-Argentina 2018
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?
World Alfalfa Congress-Argentina 2018
Alfalfa – Best Crop for a Drought
Deep Rootedness
Perennial
High Yields
High Harvest Index
High Water Productivity
Seasonal Yield Patterns
Salt Tolerance
Flexibility…!
World Alfalfa Congress-Argentina 2018
Many Thanks!
World Alfalfa Congress-Argentina 2018
Many thanks!
Wagner farm, WA state, photo