This document summarizes research on a Subsurface Water Retention Technology (SWRT) using polymer membranes installed below the root zone of crops. Key findings include: 1) SWRT doubles soil water holding capacity in the corn root zone, saving over 1 billion liters of irrigation water per hectare each season. 2) Corn yields increased an average of 235% (from 5.2 to 17.4 metric tons per hectare) over three years on soils with SWRT membranes compared to controls. 3) SWRT improved irrigation water use efficiency for corn by 278%, producing more crop yield per unit of water. The researchers conclude SWRT is a new option for

1. Long-Term Water Conservation Technology that Doubles
Production and Preserves Groundwater
Alvin Smucker, Andrey Guber, Zouheir Massri and Kurt Thelen
Department of Plant, Soil Microbial Sciences
Michigan State University,
Subsurface Water Retention
Technology
SWRT
Is a drought resilient soil water and nutrient conservation
technology sustaining agricultural production of greater
grain, cellulosic biomass and vegetables with less water
and fewer nutrients on sandy soils really needed?
Agriculture Irrigation and Precision
Technologies to Reduce Water Use
Greensboro, NC; July 27, 2015
Supported by the NRCS/CIG/USDA
Project Number 69-3A75-13-93.

2. Focal Perspectives:
 Introduction
 Soil Water Retention Technology: SWRT
 Results for sustainable production on sands.
 Mechanisms associated with yield increases
 Identifying optimal components of soil
water/crop/weather.
Retaining water at the root level of crops has been a
major focus in precision irrigation system from
technological, socio-economic, and environmental
perspectives.

3. Historical Improvements in Agriculture Production
Soil Water and Nutrient Balance
for
Best Plant Production
Fertilization and Pest Control
and
Best Management Practices
Plant Breeding
and
Plant Bioengineering

4. Four Opportunities for Production Agriculture
1. Food production needs to increase by 70% to feed a
projected global population of 9.6 billion by 2050.
Will require 60% more irrigation water at current WUE.
2. Corn plants experience between 27 and 45 drought
periods annually. Death of 1,540 tertiary maize roots
per m3/d, then regrow following rainfall or irrigation.
15.4 million roots lost per hectare per crop.
3. Most plants growing on well-drained soils, absorb
40% to 50% of rainfall and irrigation water. Due to
extremely negative water potential. < -65 to -100 hPa
4. Surface water available for irrigation agriculture in
the USA has decreased ~20% during last 30 years.

5. Volumetric soil water content storage in sands increases
as the SWRT water saving membranes are
installed closer, to the root zone.
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6. 3.6 L/h/m2SWRT
Membrane
Although contrasting textural layers within sand profiles retard
gravitational soil water drainage, strategically positioned polymer
membranes reduce infiltration to ~0 when irrigated with precision.
0 20 40 60 100
Soil depth – cm
Infiltrationrate–ml/sec/cm2
360 L/h/m2 natural sand

7. 1.5 to 3.0 mil
PE membranes
50 cm
35 cm
2:1
aspect
ratio
Polymer films were engineered into contoured linear-low
density polyethylene (PE) SWRT membranes strategically
installed below plant root zone with space available for
unlimited root growth AND drainage during excess rainfall.
- 50 to -70 hPa
SDI
Capillary
rise above
Membrane
32 cm

8. 2:1 aspect
ratio
40 cm
55 cm
1.5 to 3.0 mil
polyethylene
membrane
Vol. H2O content
24%
9%
21%
17%
14%
6%
Soil Surface
General distribution of VWC in root zone above SWRT membranes
installed at soil depths controlled by soil texture, capillary rise,
soil water retention graphics and measured in the field.
24%
21%
12%
17%
5%
Continues
across the
field
Continues
across the
field

9. HYDRUS-2D example of soil water distribution after irrigation of sand
soil profile modified by SWRT membranes with aspect ratios:
2:1 (a) after 11 days, 3:1 (b) after 6 days and 5:1 (c) after 4 days.
SWRT membranes are shown as white U-shaped troughs.
VWC
Water retention within and above SWRT membranes to near soil
by membranes having 3 different width to depth aspect ratios:
2:1 3:1 5:1
353 cm3 cm-1 236 cm3 cm-1 141 cm3 cm-1
18%
21%
24%
26%
28%
Sat. = 35.4%
21%
24%
26%
28%
16%
18%
21%
24%
26%
28%
(b) (c)(a)

10. SWRT membranes with aspect ratios of 2:1 provide best soil water
contents for optimal water conservation and crop production.

11. Excavated water and nutrient saving membrane,
30 cm wide x 15 cm deep, installed at soil
depth of 35 cm from base to soil surface.
15 cm
deep
30 cm wide

12. 12
Water lost by deep drainage
SWRT membranes double soil water holding capacity in corn
root zone, saving 1,012.7 million liters of irrigation water per
hectare during each 110 day corn cropping season.
RootZoneSoilwaterContent%
Control
No membranes
SWRT
membranes

13. Promotion of irrigated corn growth and yield by SWRT
water and nutrient saving membranes (left side) and
no SWRT membranes (right side).
June 29, 2012 in East Lansing, Michigan
Non-droughtstressedcornPlot
Droughtstressedcornplotof
13
17.1 Mt/ha of grain 9.7 Mt/ha of grain
Results for corn production during past 3 years:

14. 38 cm row Non-irrigated
control, no membrane
38 cm row Non-irrigated
SWRT membrane 2014

15. 0.00
5.00
10.00
15.00
20.00
25.00
15" Row Non Irrigated 15" Row Irrigated
MTperhectare
Corn grain yields on 38 cm rows
with SWRT Membranes - 2014
An additional 24 cm irrigation increased corn grain production
58% (308 Kg maize grain per cm water) when grown on SWRT
membranes improved water retention of sand soils. n=5
Non-Irrigated Irrigatedon

16. Treatment
MT per
hectare
Percentage
increase
Control 5.2 (5.4)* 0
SWRT
Membranes 17.4 (2.6)* 235%
* Denotes standard error.
Three - year average corn grain production on
SWRT membranes rainfed plus irrigation at
Sand Hill Farm, East Lansing, MI. 2012 - 2014.
 Mechanisms associated with SWRT membrane
promotion of plant growth and grain yields:

17. SWRT improved irrigation WUE for corn: 278%.
That is more crop per drop of water!

18. Four Opportunities for Production Agriculture
1. Food production needs to increase by 70% to feed a
projected global population of 9.6 billion by 2050.
Will require 60% more irrigation water at current WUE.
2. Corn plants experience between 27 and 45 drought
periods annually. Death of 1,540 tertiary maize roots
per m3/d, then regrow following rainfall or irrigation.
15.4 million roots lost per hectare per crop.
3. Most plants growing on well-drained soils, absorb 40%
to 50% of rainfall and irrigation water. Due to
extremely negative water potential. < -65 to -100 hPa
4. Surface water available for irrigation agriculture in the
USA is decreasing during last 30 years.

19. Growth and death (1,540 roots per m3/d ) of tertiary
roots for maize in sand soil from the onset of drought
during 32 days of severe water deficits during V10
vegetative stage. (Smucker and Aiken, 1992).
-65 hPa
100 cm 80 cm
50 cm
Soil water potential - MPa
Soil Depth:

20. Corn roots remain healthy
along surface
of SWRT membrane
at crop maturity.
20

21. Greater water retention in the root zone of corn
by SWRT subsurface membranes
increases shoot to root ratios
by 131% (2.31-fold)
Per
Single Plant
Biomass
gm.
Treatments

22. A
B
C
B
0
1
2
3
4
5
6
ETOHMg/Ha
Control SWRT Membranes
2012
2013
Optimal soil water contents in plant root zone promoted
corn biomass with higher conversion rates to ethanol.

23. Sustainable Food
Production
on Sands
Health and
Environmental
Protection
of
Groundwater
Maximum
Cellulosic
Biomass
Production
on Sands
 Doubles production
with half the
irrigation water
 Produces more
biomass of
renewable
cellulosic
biofuels
 Does drought
tolerance reduce
production potential
of irrigated maize?
Reduces greenhouse
gas production
Minimizes
groundwater
contamination
16S Ribosomal
profiles with soil depth
in SWRT and control
sands.
EMO/HYDRUS models
(Current research)
 Reduces surface
erosion of soil P (Year around
soil cover
 Saves 40% more N and K
in plant root zone
 Greater
soil carbon
sequestration
Subsurface Water Retention Technology is a new option for
increasing yield, maximizing rainwater retention, conserving
irrigation water resources and reducing salinity and groundwater
contamination in humid, arid and semi-arid regions globally.

24. 3x
x 5
EMO
Soil type,
Crop type,
Expected
clim ate
condition
etc.
INP UT
x 2
x1
x 4
7x
x 6
x 8
No
Yes
420
Irrigation Sequence, y(t)
SWRT
Solution (x,y(t))
VariablesforOptimization
Time (mths), t
Final Solution (x*,y*(t))
Supplem ental Water, Y(x,y(t))
REF(x,y(t))
Terminate?
Initialize Pop(x,y)
Create New Pop(x,y)
x,y(t)
WEF(x,y(t))
Evaluate Pop(x,y)
Membrane Parameters (x)
HYDRUS
Incorporating multiple soil plant
and atmosphere conditions
and responses to SWRT into an
Evolutionary – Multi-objective
Optimization (EMO) model
coupled with HYDRUS 3D.
 Future water conservation in the USA and globally
362 variables
@ 103 objectives

25. Identify primary components of soil water - plant - weather.
1. Can we improve the Ecosystem Services of agriculture
with new technology during changing climates?
2. Does drought tolerance reduce production when soil water
is optimized by irrigation or new biotechnologies?
3. Optimum budgets for long and short term technologies?
4. Prioritization of reasons for increasing grain and biomass?
5. How can we best optimize sustainability?

26. Collaborative Team - Work Programs are
Essential among:
 Plant genetic bioengineers
 Hydropedologic engineers
 Soil scientists
 Agronomists
 National and global policy makers
before long-term sustainable maximum food
production can be achieved with the least
amount of water when irrigated with
optimal precision.

27. Email: smucker@msu.edu
Vadose Zone Journal. 2015. 2004-11-0166-ORA.R1-PDF0001
Journal of Soil and Water Conservation. 2014. Vol.(5):154-160 DOI 10.2489/jswc.69
Additional websites:
SWRT Webinar: https://connect.msu.edu/p7x01brb8a9/
Website search: SWRT Smucker
July 27, 2013, East Lansing, Michigan
MSU, SWRT Solutions©

28. Maximum Initial SWRT Market Potential for
U.S. Corn & Soybeans Based on Available Sandy Soils
5-Yr Avg. U.S. % Initial Initial SWRT
Crop Ac/Planted (000) SWRT Acres Acres (000)
Corn 89,885 15.0% 13,483
Soybeans 76,564 15.0% 11,485
Total 166,449 24,967
Corn & Bean Gross Revenue Max Initial
Acres (000) per Acre Market (000) 28
Economics
New SWRT
Profit (000)
$8,909 *
$5,076**
* SWRT increases profits by $661 per acre of corn.
** SWRT increases profits by $424 per acre of soybeans.
$13,985,633

29. Control 7,689 (450)* 10,710 (2674)
SWRT
Membranes
10,336 (440) 15,800 (1518)
SWRT
Increase
*Values in parentheses are standard errors of the means.
29
MSU SWRT enhancement of vegetable production
of irrigated cucumbers and peppers on a
Spinks Sand at SWMREC, 2012. N=4