on-farm response strategies to drought - idaho response strategies to drought inland nw drought...
TRANSCRIPT
On-farm Response Strategies to Drought
Inland NW Drought Forum 2013
Boise, ID Water Center
Oct 18, 2013
Howard Neibling, P.E.
Extension Water Management Engineer, University of Idaho
Response depends on:
• Water source (surface or well)
• Timing and amount of reduced water delivery
• Cropping mix that can be grown
• Irrigation systems used
• Soil depth and water holding capacity
Water Source Considerations
• Wells – Timing and amount of water supply is under
farmer control within water right or other constraints
– If total withdrawal is limited, farmer can still manage timing of reduced well flow
• Surface – Timing and amount depend on water delivery
policies and system constraints – less flexibility than with wells
3/30
4/13
4/27
5/11
5/25 6/
86/
22 7/6
7/20 8/
38/
178/
319/
149/
28
10/1
2
10/2
6
Date
Winter Grain
Spring Grain
Dry Beans
Potatoes
Field Corn
Sugar Beets
Alfalfa
Tillering
Tillering
Boot - flower
Boot - flower
Flowering
Tuber set
Pollination
Germination, Emergence
& Early Growth
Early growth New fall seedings
Timing of Crop ET and Critical Crop Stages
for Magic Valley Conditions
Timing and amount of delivery
• If limited supply can be delivered for full season at reduced rate – All crops can be grown but on limited area – Sprinkler systems can be modified to cover less area with
reduced flow – then crop stress on reduced areas can still be minimized
• If limited supply must be delivered at nearly full flow until supply is gone (e.g. leaky canals) – Only shorter-season crops can be grown – Carefully schedule system turn-on (wait till water needed) – Fill deep soils early to minimize evaporation losses and
store maximum water in crop root zone
Adjust cropping mix to fit water supply
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
Seas
on
al E
T, g
allo
ns/
acre
30-yr Average Estimated Seasonal ET, Kimberly
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
3/31 4/14 4/28 5/12 5/26 6/9 6/23 7/7 7/21 8/4 8/18 9/1 9/15 9/29 10/13
Ag
rim
et
Esti
mate
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rop
ET, in
/d
Average 30 Year Calculated ET for Typical Magic Valley Crops
Alfalfa Mean Corn Russet Potatoes Spring Grain Lawn
Irrigation system considerations
• Surface Irrigation: less water means more attention to set time and flow rates
• Sprinkler systems:
– Set or set-move systems are usually designed to be able to “keep up” all season. With reduced water
• Fix leaks (average 12% losses)and replace worn nozzles (average 13% over application)
• Use shorter set times to avoid over-watering
• Skip sets with lowest crop productivity
0
1
2
3
4
5
6
7
8
0 5 10 15 20 25 30 35
No
zzle
flo
w, g
pm
Nozzle number
WL15 wheel line: 9/64 nozzle, 32 psi
actual flow no-wear flow
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
0 5 10 15 20 25 30 35
No
zzle
flo
w, g
pm
Nozzle number
2-month old R2000 windfighter
actual flow no-wear flow
Center pivot systems
• Usually designed to apply less than peak ET
• Application per revolution limited to prevent runoff
• Therefore, apply extra water before peak ET period
• When water delivery rate is reduced – If system is over 5 years old, replace sprinkler package (poor
measured water application uniformity meant 65% of systems tested needed new sprinkler packages)
– Shut off end gun and re-nozzle
– Shut off end gun and outer span if necessary (outer span most prone to runoff)
– Run system as slow as possible without runoff to minimize evaporation losses
– Plant half to early crop and half to later crop / re-nozzle for 2nd crop
Use irrigation scheduling to best match water applied to crop need during the
growing season
• Water budget with AgriMet
• Shovel or soil probe with soil feel and appearance method
• Soil sensors with in-field data loggers
• Soil sensors with data transmitted to web server and accessible from internet
Hansen AM 400 Data Logger and atermark sensors
• Cost: about $3 5-$ 00 for, ·ire and 6 sensors
• Records data from 6 sensors every 8 hours
• Singe button disp a· sho vs 5 veeks data for each senso
• \ eatherproof and can be used in the winter
• _ 1emory stores entire season of data • ;vithout do oading • Can do \• oad at any time • Shows change in moisture, ·th
time at se ected depths • Can be set up to sho · eaching
events
Sensor source: http: · ~ :..irrometer.com!sensors.html
Data ogger source:
http:'. . ·.mkhansencom'
Decagon ECH O Probe Data Logger
• Capacitance pr be (me-asure-S dielectri~ permitth'ity)
soil
• Output in· lumetric ater c ntent
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Datalogger ab supports rain gag"' & temp sensors
ufr ctured by Decag n (Pullman, ·A)
Cost fs ·stem N'.th · soil m sture sensors, rain gage, radi transmitter ( ne set r r e-ach eld): about S j {)()
• Additi nal cost r recetYer inpickupetc. ands fu~are ( ne set this equipment
elds): about S 0
• \Vebstte: ~n ·.deca~oo .rom
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Unive~sityotldaho Extension
Data from 1 or 2 probes with soil moisture measurements at 4,8,12,18,24 and 40” transmitted to JD website for user access from any web-connectable computer.
Approximate cost for components for one field:
Gateway logger / transmitter with first year installation and data plan : $$2900
1-m probe with capacitance-type sensors and 200 ft cable to connect to Gateway: $1900
Source: local John Deere dealer
Em, i IJ'o SCA I Flat Cap Probe
F eatnu es i rtdlud e:
~ N l!l l!iiple sensors willil flexib e deplh pfaceme,nt (at W cm in crem ents) 4 Mo nitoiring ifrorn s I all 0111 deiplhs (® - 1l!D Clill ) to deep ilils la rna1l ions (> 40 metres ~ Le nglh of prnbe icusto: is,ed to st.11 it 1he app:lic,ai i 011 (p:ro be lengii h acljustab e in Ute fiel d) 4 Up to 16 selilsors on olile prob e (rnm:islure. orr moislurelsa linlty) ~ llil-b'U iH p:ro be mien tali olil and d eplh settingis, i o enha rtce selilso:r re peatabili ly 4 Fu[I servi:ce abmty. ~ Flexible con rteclivifly. for wide· rnn; ,e of d ata relri ev al opli on:s
Pro be Sea~li n g
The bottom o' the acc ess 1ube is typically sea led using a d oub e~rin; ,ed expandab~e rulb1ber bung , p:ror1{ cl irtg 2 sealing1 paints and preventing1 undlergrmmd mo·s,tnu e f ro m en1ering the t L11be . A slunry. cap~ also a,11ia'ilable.
The 1op of the a,ccess ru be is seated w ith 2 d iffelienl: top cap des ·gns, depe , din; on appU:cat ion .
Envi roSCA N Screw Cap,
•· Top cap p mi rrudes above the so ii s u IJ'f ace •· E asy to n111d and lie ad ilfy accessibl e· •· T~g1htuy.· sea ed vJlh a rnlb1ber 0-IJ'ing •· Sim pl'y u n-screi.vs, g ivirtg eas:y. access l:o 1he probe Jo:r serv.rcirtg
EnviroSCA N F m: Cap
•· A.llows ' or the probe· io sit · 'us h wilh the g rnund s,mface •· W arl:er-i "ght 3 p oin1 sea lirtg design •· PriCMdes re·adv access to lihe p rob e foll' sel!Viciing •· Avo:itlils p oleni i'all y.· oost l')" damage fi"o:n madhinery·
EnviroSCA N Screw Cap Pr1obe
Unive~sityotldaho Extension
Analyze your data through graphica l display
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Grap ical display
Unive~sityotldaho Extension
Summary: on-farm irrigation responses
• Adjust cropping mix to match timing and rate of water delivery
• Perform needed irrigation system maintenance – Set & set-move systems: fix leaks, replace worn
nozzles, replace worn or malfunctioning sprinkler heads
– Center pivot /linear: replace pressure regulators & sprinkler packages older than 4-5 years
• Use an irrigation scheduling method to match water applied to crop need throughout the season