I shared this presentation at the Great Plains Vegetable Growers Conference in St. Joseph,MO o n 1/7/2016

1. Soil Health 101
Joel Gruver
WIU Agriculture
A root-centric perspective

2. Big Hugh, how long
will it take to win
the war against
soil erosion?

3. http://www.swcs.org/documents/filelibrary/BeyondTreport.pdf
(2008)
>70yearslater

4. Reducing erosion rates to T levels
is just the beginning of
good soil management.
Well managed soil should deliver nutrients and water to
plants when they need them and keep nutrients out of
surface and ground water. Well managed soil should
minimize the effects of floods and droughts.
Well managed soil should resist compaction and other
forms of degradation.
By focusing soil conservation on enhancing soil function
instead of preventing erosion, the goal is
soil improvement as opposed to
TOLERABLE DEGRADATION.

5. Go beyond T - Manage for C!
http://soils.usda.gov/sqi/concepts/soil_organic_matter/som.html

7. Do you recognize this soil health advocate?

8. https://vimeo.com/channels/raythesoilguy

10. Grinnell Heritage Farm, owned and operated by Andy and
Melissa Dunham, has grown from three acres in 2007 to 22
acres today and produces more than 60 varieties of
certified organic plants and vegetables. The Dunham’s
understand that the health of their soil translates into
healthier crops and a more resilient farm. A fifth-generation
farmer on the Grinnell farmland, Andy has made improving
the health of the farm’s soil a major priority. “Our
philosophy is feed the soil, it will feed your plants, and then
it will feed us,” he said. Read more or
watch the three-minute video profile:Grinnell Heritage Farm.

12. Do you recognize any of these CC innovators?

13. Is this
really
possible?

14. Sound
management of
variable soils
requires a
balanced
approach – the
causes of
variability can
be managed as
well as the
effects

15. WHY?
Variation in
INHERENT
soil properties
Variation in
DYNAMIC
soil properties
Variation in
crop
management
Variation in
combine
operation
Large
spatial
variation in
crop yield
is common
Striping is normally man-made!

16. Properties
Ephemeral soil properties?

17. Have you observed this type
of contrast on your farm?
Same soil type
Crop field Fence row

22. This past fall, students in my Soil Properties class brought in paired
(Crop field & Fence Row) soils from their family’s farm. In most cases,
the fence row soils had higher carbon dioxide and ammonia production.

23. Most kits sit idle in closets 
A blast from the past 

24. What do the analytical results tell us?
More informed
decision making???

25. http://www.swcs.org/documents/filelibrary/BeyondTKarlenSMAF.pdf

26. Soil Health and Soil Quality
are NOT synonymous

27. Variation in
inherent soil
properties

28. ≠
Soils like cars have inherent
differences that are not
changed by normal
management
Thin
A
horizon
Thick
A
horizon
Ca
depleted
sub-soil
Ca rich
sub-soil
claypan no claypan

29. USDA
Textural
triangle
12
textural
classes
http://www.oneplan.org/Images/soilMst/SoilTriangle.gif
Texture is
generally
considered an
inherent soil
property

30. >12 “
10-12”
8-10”
6-8”
< 6”
Variation in texture is directly
related to variation in
plant available water

31. Which soil texture holds the most plant available water?
Adapted from Kramer 1983

33. Predicted Soil
Hydrologic Properties
The calculator predicts
soil hydrologic
properties based on soil
texture as well as
modulating factors: OM,
salinity, gravel content
and compaction
Based on data from
~ 2000 soil samples

34. x 0.47 ->
x 3.4 ->

35. In addition to texture,
soil/crop management systems
impact the 1) movement of
water, 2) storage of water, and
3) volume of soil from which
crop roots acquire water.
So how should we target our management
to most improve crop access to water?

36. x 1.10 ->
x 2.5 ->

37. x 0.88 ->
x 0.14 ->

38. x 0.75 ->
x 0.32 ->

39. Water movement
(infiltration vs. run-off)
and depth/volume of soil
from which crop roots
acquire water are much
more sensitive to management
than
water holding capacity

40. Management decisions influence both
1)CROP ROOTING POTENTIAL
2) SOIL CONDITIONS
Less of a particular crop/cover crop’s rooting potential
is realized when soil conditions impede
root growth and function.
Physical factors – compaction, poor drainage, high or low
temperature
Chemical factors – acidity/metal toxicities, nutrient
deficiency/excess, salinity
Biological factors – root herbivores/pathogens

41. Effectiveness of in-field conservation
practices should be assessed with respect to
impact on root growth and function
NOT tons of soil loss.

42. Soil/crop management strategies
for optimum root growth and function
• Alleviate existing physical, chemical and/or biological
barriers to root growth
• Prevent development of physical, chemical and/or
biological barriers to root growth
• Plant crops on soils for which they are well adapted
• Grow strategic sequences of crops/cover crops to
maximize a positive cycle of root zone improvement
•Treat seeds/roots with biological inoculants to enhance
root-enhancing biological relationships

43. Acute
root
disease
 Chronic Root Malfunction 
VS.
Chemical, physical and biological
factors cause CRM!
is the norm in agriculture

44. Seed treatments can prevent
acute root disease and insect
feeding but do not solve the
problem of CRM

45. STEEP, DEEP and CHEAP
Breeding goals proposed by
J. Lynch
RCA = Root cortical aerenchyma
We can
breed crops
with more
robust
roots!

46. Three primary factors affecting flooding tolerance in plants have been
reported: (1) the ability to grow adventitious roots
at the soil surface during flooding; (2) the capacity to form root
aerenchyma; and (3) tolerance to toxins (e.g., Fe 2+, H2S) under
anaerobic soil conditions. By analyzing these components separately, it
should be possible to perform selections for genotypes exhibiting varying
degrees of flooding tolerance.

47. Increased efficacy of symbiotic N fixation can be
achieved by selecting not only better bacteria but
by selecting the best combinations of host plants
and bacteria.
…targeted efforts to select superior plant:microbe
partners will bring benefits under a wider range of
environmental conditions.

48. We are conducting trials of AZ-Green from TerraMax

49. competition parasitism
antibiosis induced resistance
4 main types of microbial
interactions that promote root health
Sales reps should know
how their biological
products work

50. Dramatic effect of the
inclusion of compost in
potting media on the
health of pepper roots

51. Aluminum
toxicity
Aluminum
toxicity
Chemical toxicities
inhibit root growth & function
Al toxicity is very common in
the SE US and in tropical
countries like Brazil

53. Nutrient availability affects root growth
but affects top growth more

54. N and P promote root branching and proliferation

55. Ontario Ministry of Ag and Food
Why do crops on tiled-drained land
tend to be more drought resistant ?

56. Ontario Ministry of Ag and Food
Do crop roots grow toward water?
Roots elongate directed by gravity in AEROBIC soil!

57. Air pruning promotes root branching

58. Soil block system for growing tomato transplants
Air pruning promotes root branching
No root spiraling

59. Soil can
get too
hot for
optimal
root
growth!
Soil aeration also affects soil temperature
which strongly affects root growth rate

60. Brady and Weil (2002)Brady and Weil (2002)
Sub-soil water
and nutrients
Compaction strongly impacts root growth and function

61. Adapted from Hunt et al. (1986)
Tillage can positively
and negatively affect
root growth and
function

62. Long term no-till
(w/ healthy soil biology)
Intensive tillage
Ontario Ministry of Ag and Food
Plow pan
Network
of cracks
and
biopores

63. Annual
ryegrass
roots
penetrating
> 40”
Radish
roots
> 40”
after 1.5
months

64. Land preparation
vs.
Soil Preparation

65. http://www.slideshare.net/pd81xz/ot-b-246

66. http://www.slideshare.net/pd81xz/ot-b-246

67. http://www.slideshare.net/pd81xz/ot-b-246

68. How regularly do you
look at roots?

69. You really won’t know what is happening
underground unless you take a look…

70. All you need is
a shop-vac and
a hose :-> !
Its just like going to the dentist!

71. Healthy
shoot growth
and high
yields
white color
proliferate
in all
directions
extensive
growth into
the sub-soil
minimal
evidence of
deformities
Efficient
use of soil
resources
What should you look for?

72. Not all healthy roots are white in color!!

73. How is it possible for healthy crops to
grow with such a limited rooting volume?

74. Wading pools do NOT provide an optimal rooting zone
but a small root system can support healthy shoot
growth with ample moisture and nutrition.

75. ?

76. Mural on my shed
inspired by JE Weaver’s illustrations
I have heard people say that
horticultural crops just have
wimpy inefficient root systems…

77. http://www.sustainablefarmer.com/pdflibrary/library-
rootdevelopment.pdf

78. Lettuce roots
after 3 weeks
The roots on the right
were grown in compacted
soil, the roots on the left
were grown in soil with
good structure.
1ft

79. Extensive
root system
of a
flowering
lettuce
plant
5’

80. Asparagus
root system
after 6
years
10 feet

81. Depth
(ft) %sand %silt %clay
0-0.5 31 34 35
0.5-1 33 29 38
1-2 23 31 47
2-3 20 31 49
3-4 22 34 44
4-5 25 37 37
Soil particle size variation with depth at
Dr. Weaver’s research farm (Lincoln, NE)
This is not a sandy soil!

82. http://content.ces.ncsu.edu/vegetable-crop-irrigation

83. Crop Sensitivity Rooting Impact of drought Moisture
to drought Depth Management

84. Shallow
broccoli
onion
Irish potato
Medium
green beans
edamame
beet
carrot
cantaloupe
cucumber
eggplant
pepper
summer squash
Deep
lima beans
lettuce
okra
parsnip
pumpkin
winter squash
tomato
watermelon
Relative root depths of vegetable crops
(according to Dr. Sanders’ bulletin)
Partly a function of length of growing season/timing of harvest

85. ASM = Available Soil Moisture = % of water between field capacity and wilting point
Key info for scheduling irrigation

86. Tensiometer

88. Vegetable crops normally leave more residual N
both in crop residues and as mineral N
than grain crops.
While much of this N may be dissipated into the
environment before the next crop,
high mineral N (nitrate + ammonium) values are
commonly found in the spring after vegetable crops.
Mineral N retained from the previous year is mostly found in
deeper soil layers. Therefore, choosing crops with deep root
systems is key to utilizing N retained from previous crops.
Large differences in the ability to take up N from deeper soil
layers are found among vegetable crops.

89. 0 - 18”
18 - 36”
36” - 54”
0 55 110 165
Only 55% of N in root zone of following crop
Veg crop sequences with poor N utilization
lbs of N per acre (spring after preceding crop)
Precedingcrops
Followingcrops
Rooting
depth
Rooting
depth
Rooting
depth
http://orgprints.org/256/1/ActaHort_utilising_differences.pdf
0 – 1.5’ 3’- 4.5’1.5’ – 3’

90. 0 - 18”
18 - 36”
36” - 54”
0 55 110 165
85% of N in root zone of following crop
Veg crop sequences with high N utilizationPrecedingcrops
Followingcrops
Rooting
depth
Rooting
depth
Rooting
depth
http://orgprints.org/256/1/ActaHort_utilising_differences.pdf
0 – 1.5’ 3’- 4.5’1.5’ – 3’
lbs of N per acre (spring after preceding crop)

91. What are these
crazy people
trying to do ?
Location:
Laurenburg, NC
Date: 1961
Trying unsuccessfully
to change an old highly
weathered soil in North
Carolina into a deep
fertile “Prairie” soil

92. http://mnvconsulting.eu/2010/02/05/the-bowmont-catchment-initiative/
The giant plow on the previous slide was
designed for burying flood sediment

93. The advantage of the USGA green is its
long-term research-base and proven
performance in the field. If properly built
and maintained, golfers rarely face poor
putting conditions. The biggest drawback is
collecting the necessary materials and the
cost of construction. One USGA green
costs ~$40,000 to construct.
http://www.turspec.com.au/index.php?construction
Sometimes it makes sense to dramatically
modify soil inherent properties

94. The current OM level in a soil is a
result of the long-term balance
between organic inputs and outputs
Yield enhancing practices will not
build SOM if losses increase at a
comparable rate
Organic outputs

95. ”But with the removal of water through furrows, ditches, and
tiles, and the aeration of the soil by cultivation, what the
pioneers did in effect was to fan the former simmering fires…
into a blaze of bacterial oxidation and more complete
combustion. The combustion of the accumulated organic
matter began to take place at a rate far greater than its annual
accumulation. Along with the increased rate of destruction of
the supply accumulated from the past, the removal of crops
lessened the chance for annual additions. The age-old process
was reversed and the supply of organic matter in the soil
began to decrease instead of accumulating.”
William Albrecht – 1938 Yearbook of Agriculture
Drainage + Tillage + Lime + N + harvest = Accelerated loss of SOM

96. Soil Changes After Sixty Years of Land Use in Iowa
Jessica Veenstra, Iowa State University, 1126 Agronomy Hall, Iowa State
University, Ames, IA 50010
Soils form slowly, thus on human time scales, soil is essentially a non-
renewable resource. Therefore in order to maintain and manage our limited
soil resources sustainably, we must try to document, monitor and understand
human induced changes in soil properties. By comparing current soil
properties to an archived database of soil properties, this study assesses
some of the changes that have occurred over the last 60 years, and attempts
to link those changes to natural and human induced processes. This study
was conducted across Iowa where the primary land use has been row crop
agriculture and pasture. We looked at changes in A horizon depth, color,
texture, structure, organic carbon content and pH.
Hill top and backslope landscape positions have been
significantly degraded.
Catchment areas have deeper topsoil.

97. OM enriched
sediment
OM depleted
top soil

98. Redistribution of topsoil is an expensive but
potentially highly effective method of improving root
growth and function.
Soil landscape restoration involves moving soil from
areas within a field where it has accumulated
through erosion to areas where it has been lost
through erosion.
Strategic redistribution of topsoil - ranging from
raised beds to reuse of dredge materials - merits
consideration, especially in high value
horticultural crop production

104. Perennial-based
rotation systems
Tree crops
Permanent pasture systems
Winter cover crops
Green Lands = Blue Waters
Conservation
Cropping Systems

105. Soil Health is Not an End in Itself
The ultimate purpose of researching and
assessing soil health/quality is not to achieve
high aggregate stability, biological activity, or
some other soil property.
The purpose is to protect and improve long-term
agricultural productivity, water quality, and
habitats of all organisms including people. We
use soil characteristics as indicators of soil
health, but in the end, soil health must be
identified by how well soil performs its functions.