Taking Control of Your Drainage System

Advancing Agricultural Performance®
and Environmental Stewardship
February 19, 2015
Ames, Iowa
Taking Control of Your
Drainage System
Nathan Utt
Ecosystem Services Exchange
nathan@ecoexch.com
Funded in part by the soybean checkoff
Why do farmers install drainage?
• Improved plant health
• Improved trafficability
Drainage can have
an impact on water
quality
Photo courtesy http://www.epicinter.net/typical/
We live and work in a drained
landscape.
Can we protect water quality while still ensuring
excellent conditions for crop production?
Ecosystem Services Exchange
• Founded in 2010 with the goal of developing market-based
solutions to water quality issues
• Plan Drainage Water Management and Sub-Irrigation
systems
• Developing nutrient trading markets in the Midwest
• Certified Technical Service Provider for the NRCS
www.EcoExch.com
Ag Drainage Management Coalition
• Industry-led organization addressing
water quality and drainage concerns
• Work with USDA and universities on research and
development of new technologies
• Provide training workshops to farmers and
contractors
www.admcoalition.com
Improving Water Quality
Improving Yield
1.
2.
3.
4.
Saturated Buffers
Drainage Water Management
Sub-Irrigation
Denitrifying Bio-Reactors
Saturated Buffers
A new approach to water quality
Saturated Buffers – They look the same to me…
Saturated Buffers – How they work
Image courtesy Agri Drain Corp.
Saturated Buffer Demonstration Project
• 4 states, 15 demonstration
locations
• ADMC is monitoring
–
–
–
–
Flow
Water Quality (N and P)
Soil Parameters
Stream bank movement
• Over 50% reductions in
annual nitrate loss
• No direct impact on yield
anticipated
Will a saturated buffer work on my farm?
What does the field need to be like?
• Interim NRCS standard 739
– Vegetated Subsurface Drain Outlet
• Most important site requirements
1. Buffer strip – grass, trees, etc.
2. Tile main to intercept
3. Hydraulic gradient – someplace for the water to go
• Other important factors
–
–
–
Soil conditions
Buffer dimensions/topography
Field Topography
Saturated Buffer: Soil Conditions
• Soil must allow you to maintain a high water table
– Restrictive layer
– Avoid sand/gravel lens
Buffer Characteristics
• At least 30 ft wide
• Well established vegetation
• Flat along the ditch
– Up to 2 ft of elevation change along length of buffer
– At least 300 ft long
– Longer buffer may be needed for larger tile mains
Improving Water Quality
Improving Yield
1. Saturated Buffers
2. Drainage Water Management
3. Sub-Irrigation
Drainage Water
Management
Drainage Water Management: How it works
Winter
Spring
Summer
Fall
Only drain what you need, when you need it!
Drainage Water Management
An optimum water table
Desired water table depth varies throughout the year based on:
•
Soil type
•
Crop
•
Drainage intensity
•
Planting Date
The water table is only elevated if Mother Nature
gives you some extra water to catch
Drainage Water Management: What it does
• Improve crop yield
– Less tile flow means more water is left in the field with the
crop
• Improve water quality
– Less tile flow means less nitrate leaving the field
• Up to 75% reduction in annual nitrate load
– Manage tile flow during manure applications
• Other benefits
–
–
–
–
Create wildlife habitat
Flood mitigation
Reduce subsidence in muck soils
Reduce plugging from iron ochre
• It just makes sense!
Drainage Water Management: Designed to be different
• Works best on flatter landscapes
– Control structures required every two feet of
elevation change
• Existing systems can sometimes be retrofitted
• Systems generally need to be designed to be
managed
Photo courtesy Keith Rowher
Sub-Irrigation
Sub-Irrigation: Maintaining the optimum water table
•
•
Desired water table depth varies throughout the
year based on:
− Soil type
−
Crop
−
−
Planting Date
Drainage intensity
Water is pumped into the system
Sub-Irrigation: How does it work?
•
Drainage mode
– Water table is lowered for better aeration of root zone
– Field trafficability is improved
Impermeable Layer
Sub-Irrigation: How does it work?
•
Sub-Irrigation mode
– Water table is managed at optimum level
– Water moves upward via capillary rise, providing roots
with a healthy combination of water and oxygen
Impermeable Layer
Will a Sub-Irrigation system
work in my field?
The Three S’s
•
Water Source
– Adequate supply during the dry part of the summer
• Plan for 2 – 5 gpm/acre
– Avoid surface water that contains a lot of sediment
• Your laterals will silt in over time
•
Right Soils
– A tight layer that will keep water from moving downward
•
Good Surface
– You will need at least one control structure for every foot of
elevation change
– Flatter and/or uniform slopes are less expensive than steep and/or
undulating ground
A Good Surface
The flatter the better!
Image courtesy Agri Drain Corp
The flatter the better!
How flat is flat?
– 1.0’ elevation change per zone
• Can be stretched out to 2.0’ for DWM
– Every zone requires its own structure
– At least one control structure for every foot of
elevation change
Image courtesy Agri Drain Corp
The flatter the better!
Image courtesy Agri Drain Corp
What if it’s not that flat?
Image courtesy Agri Drain Corp
What if it’s not that flat?
Image courtesy Agri Drain Corp
What if it’s not that flat?
Image courtesy Agri Drain Corp
What if it’s not that flat?
• How much slope is ok?
– 1.0’ to 1.5’ elevation change per zone
– Every zone requires its own structure
– At least one control structure for every foot of change
• Uniform slopes can work ok
• Undulating ground gets tricky
Image courtesy Agri Drain Corp
What yield results can I
expect?
Yield Impact from Drainage Practices
• Study of Ohio’s poorly drained soils
• Compared to lands with adequate surface drainage,
• Subsurface drainage improvements may increase yields by
25-30 bu/ac for corn and 3-12 bu/ac for soybean.
• Compared to lands with adequate subsurface drainage,
and where conditions are appropriate.
• Drainage Water Management may increase corn and
soybean yield on average by 7.0% and 3.6%, respectively.
• Compared to lands with adequate subsurface drainage,
and where conditions are appropriate,
• Sub-Irrigation/controlled drainage may increase yields by
25-60 bu/ac for corn and 9-12 bu/ac for soybean.
Ohio State University/USDA-ARS Crop Yield Data
Sub-Irrigation Yield Impact: Fulton County, OH
250
Yields are more
consistent
Corn Yield (bu/ac)
200
150
100
Dry summer
50
0
1994
1996
1998
2000
Sub-Irrigation
2002
2004
2006
2008
Drainage Only
J. Allred et al, Crop Yield Summary for Three WRSIS in NW Ohio. Applied Eng. in Ag. Vol. 30(6):889-903
2010
Sub-Irrigation Yield Impact:
Missouri clay-pan soils
Yield increase over non-drained control
Year(s) and Environment
DO 20’
DSI 20’
---Bu/acre---
DO 20’
DSI 20’
--------%--------
06: Dry-Moderate
8
72
6
55
02,05,12,13: Wet-Dry
14
70
22
108
03,07: Wet-Moderate
26
56
25
48
04,08,09,10,11: Wet-Wet
35
31
25
22
Average
20
57
20
58
DO = Drainage Only
2004-2005: PCU, Irrigation,
Drainage on NU and Yield.
Nelson et al., 2009. Agron. J.
DSI = Drainage and Sub-Irrigation
2006-2007: N Source & IWMS on
Yield
Nelson and Motavalli, 2014. App. Eng.
in Agric.
2008-2010: IWMS and High Yield
Hybrids
Nelson et al., 2012. Intl. J. Agron.
Slide courtesy Kelly Nelson, 2014 Drainage Research Forum. Ames, IA
Wrapping things up…
• Saturated Buffers
– New practice for improving water quality
• Drainage Water Management and Sub-Irrigation
–
–
–
–
Improved and stabilized yields
Improved water quality
Remember the three S’s
Source, Soils, Surface
• Designed right
• Installed correctly
• Managed properly
Questions?
Nathan Utt
Agricultural Engineer
Ecosystem Services Exchange
nathan@EcoExch.com
402-405-3995
Image courtesy Keith Rohwer
Sub-Irrigation: Automated Control
• Automated control structures for managing
water levels
• Integrated pump controls
• Web access for remote monitoring and
control
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