3:24:32 am 1 of 32 advancing sdi for lower value crops - opportunities and challenges freddie lamm...
TRANSCRIPT
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ADVANCING SDI ADVANCING SDI FOR LOWER VALUE FOR LOWER VALUE CROPS - OPPORTUNITIES CROPS - OPPORTUNITIES AND CHALLENGESAND CHALLENGES
Freddie LammProfessor and Research Irrigation EngineerKSU Northwest Research-Extension Center, Colby, [email protected]
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Subsurface drip irrigation (SDI) Subsurface drip irrigation (SDI) applies water below the soil applies water below the soil surface to the crop root zone with surface to the crop root zone with small emission points (emitters) small emission points (emitters) that are in a series of plastic lines that are in a series of plastic lines typically spaced between typically spaced between alternate pairs of crop rows. alternate pairs of crop rows.
SDI, a definition
Soil wetting pattern.
Installation of SDI driplines.
Most driplines in Great Plains are at depth of 0.3 to 0.45 m.
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Subsurface drip irrigation is not the same and should Subsurface drip irrigation is not the same and should not be confused with subirrigation. not be confused with subirrigation.
Subirrigation applies water below the ground surface Subirrigation applies water below the ground surface by raising the water table to within or near the root by raising the water table to within or near the root zone. zone.
What is Subsurface Drip Irrigation?
This is SDI This is subirrigation
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No irrigation system can save water without good No irrigation system can save water without good management imparted by the producer. management imparted by the producer.
Irrigation Systems and Water Savings
Additionally, some systems although perhaps more Additionally, some systems although perhaps more complicated in design and number of components may complicated in design and number of components may inherently result in better water management.inherently result in better water management.Generally, farmers obtain improvement by moving to the right in figure above.
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Improved Management with Irrigation Systems
This concept can perhaps be considered as This concept can perhaps be considered as “purchasing improved management capabilities upfront”.
It has been said that one of the principal reasons that It has been said that one of the principal reasons that pressurized irrigation systems such as center pivot pressurized irrigation systems such as center pivot sprinklers (CP) and subsurface drip irrigation (SDI) are sprinklers (CP) and subsurface drip irrigation (SDI) are considered easier to manage than surface irrigation is considered easier to manage than surface irrigation is because they remove the surface water transport because they remove the surface water transport phenomenon from the management.phenomenon from the management.
Both center pivot sprinkler irrigation and SDI are well Both center pivot sprinkler irrigation and SDI are well suited for automation (monitoring and control).suited for automation (monitoring and control).
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Conserving WaterConserving Water
Howell and Evett (2005) correctly point out that Howell and Evett (2005) correctly point out that difficulties can arise if incompatible temporal and difficulties can arise if incompatible temporal and spatial scales are used in statements about spatial scales are used in statements about effective water use. effective water use.
For example, water savings from a reduction in deep For example, water savings from a reduction in deep percolation may be inconsequential if the temporal scale percolation may be inconsequential if the temporal scale is large enough to allow return to the aquifer. is large enough to allow return to the aquifer.
Similarly, reduction of runoff is not a water savings on a Similarly, reduction of runoff is not a water savings on a large spatial scale when the runoff can be reused at a large spatial scale when the runoff can be reused at a downstream location in the basin. downstream location in the basin.
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Microirrigation is the overarching term that includes Microirrigation is the overarching term that includes surface drip irrigation (DI), subsurface drip irrigation surface drip irrigation (DI), subsurface drip irrigation (SDI), microsprinkler and bubbler irrigation. (SDI), microsprinkler and bubbler irrigation.
Microirrigation in USA
The rate of growth of The rate of growth of DI and SDI is quite DI and SDI is quite high in the USA.high in the USA.
In the US Great Plains In the US Great Plains we are most we are most interested in SDI interested in SDI because it allows us to because it allows us to consider consider microirrigation for microirrigation for lesser-value lesser-value commodity crops such commodity crops such as cotton and corn.as cotton and corn.
Year
2003 2008 2013
La
nd
are
a (
100
,00
0 h
a)
0
2
4
6
8
10
12
DI SDI
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SDI is also of SDI is also of major major interest in interest in several other several other states.states.
SDI in USA
In 2013, the ten USA states with the largest SDI area (289,811 ha) In 2013, the ten USA states with the largest SDI area (289,811 ha) comprise over 93% of the total SDI area but have a wide variation comprise over 93% of the total SDI area but have a wide variation in the ratio of SDI/(SDI+DI) land area. in the ratio of SDI/(SDI+DI) land area.
SDI land area in Kansas and Texas has grown 127% and 28%, SDI land area in Kansas and Texas has grown 127% and 28%, respectively in the last 5 years according to the USDA-NASS data. respectively in the last 5 years according to the USDA-NASS data.
SDI land area has grown 89% in USA during last 10 years.SDI land area has grown 89% in USA during last 10 years.
US State
Arizona California Florida Georgia Kansas Nebraska N. Mexico Oregon Texas Washington
La
nd
Are
a (
10
00
ha
)a
nd
Pe
rce
nt
SD
I0
20
40
60
80
100
120
140 SDI land areaPercent SDI2013
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We suspect that USDA-NASS (Statistical group in USDA) We suspect that USDA-NASS (Statistical group in USDA) is not representing all the SDI area in the Great Plains. is not representing all the SDI area in the Great Plains.
For example, in Kansas NASS only projects about 8,100 For example, in Kansas NASS only projects about 8,100 ha, where we think 14,200 ha might be more realistic. ha, where we think 14,200 ha might be more realistic. NASS data overtime does not match with installation NASS data overtime does not match with installation capacities (800-1,200 ha acres/year) that seem to be capacities (800-1,200 ha acres/year) that seem to be occurring in Kansas.occurring in Kansas.
In Texas, NASS reported 69,185 ha, while the single High In Texas, NASS reported 69,185 ha, while the single High Plains Water Conservation District (2014) shows physical Plains Water Conservation District (2014) shows physical locations for 4263 SDI systems covering 107,356 halocations for 4263 SDI systems covering 107,356 ha (http://www.hpwd.org/s/SDI_2013.pdf).
SDI in USA
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The components of The components of SDI systems can be SDI systems can be easily and easily and economically economically designed to designed to accommodate the accommodate the field size.field size.
Economics for SDI
Lower-valued commodity crops, such as cotton and corn, may Lower-valued commodity crops, such as cotton and corn, may only be profitable with SDI because of the ability to amortize SDI only be profitable with SDI because of the ability to amortize SDI system and installation costs over the multiple years of system and installation costs over the multiple years of operation.operation.
20 40 60 80 100
Percent of full size area
20
40
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80
100
Per
cen
t o
f fu
ll si
ze c
ost
CPSDI 1:1 unity line
Full size -- 125 acre CP, 155 acre SDI50 ha CP and 63 ha SDI
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SDI can be used for small, frequent, just-in-time irrigation SDI can be used for small, frequent, just-in-time irrigation and nutrient applications directly to crop root system.and nutrient applications directly to crop root system.
The primary ways that SDI could increase crop water The primary ways that SDI could increase crop water productivity (WP), productivity (WP), More crop per drop More crop per drop are: are: Reduction and/or elimination of deep drainage, irrigation Reduction and/or elimination of deep drainage, irrigation runoff, and soil water evaporationrunoff, and soil water evaporationImproved infiltration, storage, and use of precipitation Improved infiltration, storage, and use of precipitation Improved in-field uniformity and targeting of plant root Improved in-field uniformity and targeting of plant root zone zone Improved crop health, growth, yield, and qualityImproved crop health, growth, yield, and quality
Efficiency Concepts with SDI
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Does SDI Does SDI really increase really increase crop per drop?crop per drop?
Water Savings with SDI
There is growing evidence from our studies and others in the Great There is growing evidence from our studies and others in the Great Plains that SDI can stabilize yields at a greater level than alternative Plains that SDI can stabilize yields at a greater level than alternative irrigation systems when deficit irrigated. irrigation systems when deficit irrigated.
0 1 2 3 4 5 6 7
Irrigation capacity (mm/day)
0
5
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20
Co
rn y
ield
(M
g/h
a)
Incanopy sprinkler, 1996-1999 (Wet years)Incanopy sprinkler, 2000-2001 (Dry years)Subsurface drip, 1996-1999 (Wet years)Subsurface drip, 2000-2001 (Dry years)
KSU-NWRECColby, Kansas
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Does SDI Does SDI really improve really improve nutrient nutrient management?management?
Nutrient Management with SDI
Our studies have shown that using 75% of full Our studies have shown that using 75% of full irrigation with SDI, our corn yields plateaued at irrigation with SDI, our corn yields plateaued at approximately 80% of typical nitrogen applications.approximately 80% of typical nitrogen applications.
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Co
rn g
rain
yie
ld (
Mg
/ha
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0.24
0.28
0.32
WP
(M
g g
rain
/h
a-c
m)
A
NU
(M
g N
/ha
)
0 40 80 120 160 200 240 280 320Applied nitrogen (kg/ha)
YieldApparent Nitrogen UptakeWater Productivity
Total 1994 irrigation, 10.9 inches
SDI Fertigation, Colby, KS, 1994-96
1994 irrigation, 277 mm
1995 irrigation, 305 mm
1996 irrigation, 152 mm
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What about What about
SDI and Site Specific Irrigation (SSI)?SDI and Site Specific Irrigation (SSI)?
Irrigation Systems
Well, this topic heavily dives into the semantics here. Well, this topic heavily dives into the semantics here. The SDI system consists of a specific number of zones created in the The SDI system consists of a specific number of zones created in the original design and at the time of installation. Although, not original design and at the time of installation. Although, not impossible, it may be economically impractical to change the zone impossible, it may be economically impractical to change the zone configurations at a later time. configurations at a later time. Breaking the SDI system up into additional zones at the design and Breaking the SDI system up into additional zones at the design and installation phases adds costs to the system, but is warranted in installation phases adds costs to the system, but is warranted in some circumstances. Ideally, the zone characteristics are initially some circumstances. Ideally, the zone characteristics are initially carefully considered.carefully considered.
SDI’s technical competiveness with CP systems probably lies more closely with its precise water and nutrient placement.
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Irrigation SystemsFor example, here is a two zone SDI system, each with two For example, here is a two zone SDI system, each with two subzones to aid with flushing.subzones to aid with flushing.
Additional Additional complexity complexity is designed is designed as as necessary.necessary.
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Irrigation Systems
So, So, nownow if we assume we do have a very if we assume we do have a very efficient and robust method to apply irrigation efficient and robust method to apply irrigation to our crops, we still need efficient and robust to our crops, we still need efficient and robust management schemes to result in optimal crop management schemes to result in optimal crop production and optimal use of the limited production and optimal use of the limited water resource. water resource.
Management of Irrigated Crop Production
So now let’s bridge to So now let’s bridge to
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The most common definition of irrigation The most common definition of irrigation scheduling is simply the determination of scheduling is simply the determination of when and how much water to apply.when and how much water to apply.
We propose a new 21st century definition that We propose a new 21st century definition that can be stated as can be stated as the process of delaying any the process of delaying any unnecessary irrigation with the hope that the unnecessary irrigation with the hope that the cropping season ends before the next irrigation cropping season ends before the next irrigation is needed. is needed.
Management of Irrigated Crop ProductionConcepts of irrigation scheduling
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The crucial meaning of these two alternative The crucial meaning of these two alternative definitions is not fundamentally different, but the definitions is not fundamentally different, but the complexity of advancing irrigation scheduling is best complexity of advancing irrigation scheduling is best illustrated by the second definition which for illustrated by the second definition which for simplicity, we will designate as conservation-simplicity, we will designate as conservation-oriented (CO) irrigation scheduling. oriented (CO) irrigation scheduling.
The second definition also requires robust and The second definition also requires robust and reliable irrigation scheduling protocols that can help reliable irrigation scheduling protocols that can help provide confidence to the irrigator that water provide confidence to the irrigator that water conservation, high crop water productivity, and conservation, high crop water productivity, and economic profitability will not be mutually economic profitability will not be mutually exclusive.exclusive.
Management of Irrigated Crop ProductionConcepts of irrigation scheduling
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Modern scientific irrigation scheduling (IS) uses a Modern scientific irrigation scheduling (IS) uses a single approach or combination of weather-, soil- single approach or combination of weather-, soil- or plant-based approaches.or plant-based approaches.The weather-based approaches generally calculate daily or hourly The weather-based approaches generally calculate daily or hourly evapotranspiration (ET) from weather data and then use a evapotranspiration (ET) from weather data and then use a checkbook approach with precipitation and irrigation as deposits checkbook approach with precipitation and irrigation as deposits and ET as a withdrawal.and ET as a withdrawal.
The soil-based approaches generally uses either changes in soil The soil-based approaches generally uses either changes in soil water levels for estimation of ET and then a checkbook approach water levels for estimation of ET and then a checkbook approach or uses a critical measured soil water level as a trigger for an or uses a critical measured soil water level as a trigger for an irrigation event.irrigation event.
The plant-based approaches generally use a measured or The plant-based approaches generally use a measured or remotely-sensed characteristic of plant water stress to trigger an remotely-sensed characteristic of plant water stress to trigger an irrigation event.irrigation event.
Management of Irrigated Crop ProductionConcepts of irrigation scheduling
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Although there is a wealth of literature on Although there is a wealth of literature on irrigation scheduling in reference books, irrigation scheduling in reference books, journal articles, symposium proceedings, and journal articles, symposium proceedings, and extension publications, effective methods extension publications, effective methods have not been widely adopted by irrigators. have not been widely adopted by irrigators.
Many of the impediments are cultural, but Many of the impediments are cultural, but there are sometimes questions about the there are sometimes questions about the accuracy of the irrigation scheduling accuracy of the irrigation scheduling procedures.procedures.
Management of Irrigated Crop ProductionConcepts of irrigation scheduling
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When the When the accuracy of accuracy of irrigation irrigation scheduling is scheduling is perceived to be perceived to be an issue, there an issue, there is a great is a great impediment to impediment to adoption.adoption.The economic penalty of over-applying water is usually many times less than that of under-applying water.In Kansas, for our crops and water costs, maybe 8 to 17 times less.
Management of Irrigated Crop ProductionReducing irrigator uncertainty
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For these advanced, more data intensive irrigation For these advanced, more data intensive irrigation scheduling methods, questions arise about provision scheduling methods, questions arise about provision for enduser versus autonomous system control.for enduser versus autonomous system control.Some of my colleagues think busy irrigators are Some of my colleagues think busy irrigators are willing to give up considerable control and think the willing to give up considerable control and think the complexity would discourage enduser involvement complexity would discourage enduser involvement or conversely might encourage endusers to or conversely might encourage endusers to circumvent system decisions they might not circumvent system decisions they might not understand.understand.
Management of Irrigated Crop ProductionEnduser vs. autonomous system control
These are valid issues. I would optimistically hope for a middle ground where irrigator’s ability to understand more complex protocols would evolve overtime.
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In my opinion, the greatest obstacles to In my opinion, the greatest obstacles to adoption of SDI in the Great Plains are:adoption of SDI in the Great Plains are:System cost.Germination and crop establishment. Prevention of animal and insect damage to driplines.Industry, universities, and government agencies Industry, universities, and government agencies are evaluating options that may help reduce are evaluating options that may help reduce these barriers. these barriers.
What are the Greatest Barriers to SDI Adoption in the Great Plains?
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Potential to increase economic competitiveness: Potential to increase economic competitiveness: More generic SDI designs and components More generic SDI designs and components
Studies examining system requirements and trying to Studies examining system requirements and trying to streamline the design processes streamline the design processes (e.g., Bordovsky et al., 2008 and Rogers et al., 2003)
Government cost sharingGovernment cost sharing
Greater overall yields and crop pricesGreater overall yields and crop prices
System longevitySystem longevity
System Cost as Barriers to SDI Adoption
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When When properly properly maintained maintained and water and water quality is quality is manageable manageable these systems these systems can last a long can last a long time.time.
System Cost as Barriers to SDI Adoption
0 2 4 6 8 10 12 14 16 18 20 22 24 26Time since installation, y
85
90
95
100
105
110
Per
cen
t o
f fi
rst
seas
on
flo
wra
te
K-State SDI Research Site, Colby, Kansas23 separate zones represented
1989 through 2015
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Excellent Excellent long term long term corn yields corn yields can be can be achieved.achieved.
System Cost as Barriers to SDI Adoption
1990199219941996199820002002200420062008201020122014
Year
0
2
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6
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10
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14
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Corn yield (M
g/ha)
NE SDI study area, Colby, KS 1989-2015Avg. of 3 plots for highest
yielding treatment.
26 year avg., 14.6 Mg/ha
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014
Year
0
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Co
rn y
ield
(M
g/h
a)
NE SDI study area, Colby, KS 1989-2015Avg. of 3 plots for highest
yielding treatment.
26 year avg., 14.6 Mg/ha
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Germination and crop establishment can Germination and crop establishment can be a problem under drought conditions be a problem under drought conditions prevalent in the semi-arid Great Plains.prevalent in the semi-arid Great Plains.
Cropping and tillage management can help Cropping and tillage management can help to reduce this problem. to reduce this problem. (e.g., Bordovsky et al. 2012)
Fortunately, the problem does not occur in Fortunately, the problem does not occur in every year.every year.
Germination/Crop Establishment Barrier to SDI Adoption
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Rodent damage is probably the largest barrier to Rodent damage is probably the largest barrier to greater adoption of SDI systems in the Great Plains. greater adoption of SDI systems in the Great Plains.
Of the three mentioned barriers, it is also the one Of the three mentioned barriers, it is also the one with the least thorough solutions. with the least thorough solutions.
It is not that rodent problems are widespread with It is not that rodent problems are widespread with the majority of systems being greatly affected. The the majority of systems being greatly affected. The issue is that when a widespread problem occurs on a issue is that when a widespread problem occurs on a particular system, it can be frustrating to the irrigator particular system, it can be frustrating to the irrigator and the damage may lead to system abandonment. and the damage may lead to system abandonment.
Rodent Damage as a Barrier to SDI Adoption
And bad news travels fast…………………………
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Some partial solutions to reduce or prevent Some partial solutions to reduce or prevent rodent damage are discussed in Lamm et al. rodent damage are discussed in Lamm et al. (2014). (2014).
Industry continues to look for more effective Industry continues to look for more effective solutions to this problem with a focus on solutions to this problem with a focus on materials that might be impregnated in the materials that might be impregnated in the plastic or injected into the dripline during the plastic or injected into the dripline during the irrigation event to serve as a repellent.irrigation event to serve as a repellent.
Rodent Damage as a Barrier to SDI Adoption
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Other Research Needs
Scaling the SDI systems to the desired Scaling the SDI systems to the desired and/or required complexity while and/or required complexity while addressing the skills of various end-users, addressing the skills of various end-users, locally, regionally, nationally, and locally, regionally, nationally, and internationally.internationally.
Optimizing SDI production both in Optimizing SDI production both in economical and environmentally friendly economical and environmentally friendly manners that are socially acceptable.manners that are socially acceptable.
Breaking the High Tech / Low Tech paradox Breaking the High Tech / Low Tech paradox of SDI that of SDI that “Never the twain shall meet.”“Never the twain shall meet.”
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Closing Thoughts
Modern SDI is relatively new to our Great Plains region Modern SDI is relatively new to our Great Plains region with cotton research beginning at TAMU in 1963 and with cotton research beginning at TAMU in 1963 and our KSU corn research in 1989. It can be noted that first our KSU corn research in 1989. It can be noted that first USA research with SDI can be traced to efforts in USA research with SDI can be traced to efforts in Colorado in 1913 Colorado in 1913 House (1918).House (1918).
Some of the persistent barriers mentioned here today Some of the persistent barriers mentioned here today have existed throughout its brief history.have existed throughout its brief history.
Progress continues to be made at addressing and Progress continues to be made at addressing and circumventing these barriers.circumventing these barriers.
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It cannot be overemphasized that It cannot be overemphasized that manmanagementagement and technology go and technology go
hand-in-hand hand-in-hand and both and both can only be optimizedcan only be optimized in the in the
presence of the other.presence of the other.
Presentation available athttp://www.ksre.ksu.edu/sdi/underground/LammCAU15.ppt