Transcript soilslab.cfr.washington.edu

Comparison of Soils and Leaves
of Pacific Madrone and Their
Relationship to Plant Pathology
A.B. Adams and Rob Harrison
University of Washington
Seattle, Washington
[email protected]
OBJECTIVES
• TO INVESTIGATE WHETHER PLANT
PATHOLOGY IS INFLUENCED BY SOIL
STRUCTURE AND SOIL NUTRITION.
• DETERMINED SUITABLE NUTRIENT
LEVELS FOR MADRONES.
• COMPARED TWO SITES IN TERMS OF
SOIL STRUCTION AND MINERAL
NUTRITION.
Variation in Madrone Leaves as a
Function of:
•
•
•
•
•
Seasonal variation within a healthy tree branch
Annual variation within a healthy tree branch
Variation between trees within a site
Variation between sites of various soil series
Variation associated with health or disease
status of trees
STUDY SITES ARE IN THE CENTRAL PUGET SOUND
SOME HYPOTHESES ON WHY
THERE IS URBAN DECLINE OF
MADRONES
• Madrone diseases are related to soil type
– Soil structure and function (for instance, drainage)
– Soil chemistry (for example, pH and nutrients)
• Madrone diseases are related to community
physical structure
• Madrone diseases are related to disturbances
(fire)
Pure Broadleaf Evergreen Forest of Pacific Madrone
ESPERENT SAND WITH Bw/Bs? HYPOTHESIS: THIS
SOIL SERIES GROWS HEALTHY MADRONES
SAND QUARRIES ALLOW FOR STUDY OF BASAL ROOTS IMPORTANT FOR
WATER UPTAKE , SLOPE STABILITY AND ANCHORING PLANT
PHYTOPHTHORA) INFECTS POTTED AND FIELD PLANTS THAT ARE
PERIODICALLY FLOODED. THE PROGRESSION OF PHYTOPHTHORA BELOW
ARE MADRONES GROWN IN OVERWATERED POTTED PLANTS. FLOODING
IS COMMON IN URBIC (CONSTRUCTION FILL) SOILS AND WITH POOR
DRAINAGE
• Left most plant showed initial
signs of infection, but the
watering regime was made drier
and it recovered
• Second from left - fungus
spreads from root clogging
vascular system killing plant
from top down.
• Middle - the rapidity of death
caused by root rot aids in
identifying it because the leaves
remain on the plant at the time
of death.
• Far right - all leaves eventually
abscise.
LAWTON CLAY FOUND BELOW LAWN AT LAURELHURST PARK,
SEATTLE. IS THIS IMPERMEABLE STRATA RESPONSIBLE FOR
DISEASED MADRONES GROWING HERE?
MAGNOLIA BLUFFS IS A COMPACTED CAP OF GLACIAL TILL. MADRONES
OFTEN PLAY A ROLE IN STABILIZING SLOPES, YET THIS SHALLOW HARDPAN
MAY CAUSE MADRONES TO BE NUTRIENT STRESSED?
• Lower left - Nattrassia induced branch
cankers produced black sunken centers
with areas of active pathogen growth on
the borders
• Upper right - Cankers may completely
girdle branches
• Lower right - Competition for nutrients
between the tree and fungus and girdling
of vascular tissue ultimately may cause
death in major branches or trunks of large
trees. Here the two madrone trunks to the
right (one dead with leaves, the other
alive) are from the same tree; the dead
trunk was girdled by Nattrassia.
• Undisturbed, natural
soils with madrones
are very uncommon
in the urban areas.
• Compaction and
erosion destroy
upper soil surfaces
crucial for ion
exchange and plant
nutrient uptake
AVAILABLE NUTRIENTS
• CATION EXCHANGE CAPACITY VARIES
WITH SOIL SERIES
• CEC IS HIGH IN THE FOREST FLOOR AND
A HORIZON OF THE SOIL WITH HEALTHY
PLANTS, BUT THIS ACTIVITY OCCURS IN
A VERY LIMITED DEPTH NEAR THE
SENSITIVE SURFACE.
Al
Soi l Se ries or
Location
S pan away
Everette
In dianola
Arroyos
Ca
K
Mg
P
S
Micrograms/g
560.2
9.3
69.9
8.5
32
1986
379
415
56
80
72
75
29
100
46
126
C
N
pe rcent
2.1
ND
4.8
2.1
39
3044
4.7
3.3
20.15
11.92
2.08
1
0.62
0.51
0.10
0.10
NH4
NO3
Micrograms/g
5.4
6.8
2.6
4.16
4.6
3.0
2.3
0.2
CEC IS HIGH ONLY AT THE SURFACE OF THE
SANDY THAT HAS HEALTHY MADRONES
A HIGH CEC WILL IMPROVE NUTRIENT UPTAKE. AMMONIUM
CHLORIDE EXTRACTABLE CALCIUM IS SHOWN HERE BY DEPTH.
0
FOREST
FLOOR GOOD
SITE
15
SOLID LINES
ARE POOR
SITE
30
50
0
20
40
60
95% CI CALCIUM (mMol/kg)
80
100
MADRONE LEAF NITROGEN RANGES
FROM 2 TO 2.6% AND IS RELATIVELY
CONSTANT FOR A GIVEN TREE
LOG %LEAF DRY WEIGHT
100
%N
10
%C
1
1
2
3
4
5
6
7
9
YOUNG TO OLD HEALTHY 2000 LEAVES
10
.
11
12
A GOOD LEVEL FOR PHOSPHOROUS IN
MADRONE LEAVES IS 2000 PPM
LEAF MACRONUTRIENTS (PPM)
12000
10000
Ca
K
Mg
P
S
8000
6000
4000
2000
0
1
2
3
4
5
6
YOUNG TO OLD HEALTHY 2000 LEAVES
7
.
9
10
11
12
A PHOSPHOROUS DEFICIENCY WAS SUGGESTED BY
PURPLISH COLOR AROUND LEAF VEINS IN
DISEASED TREES ON MAGNOLIA BLUFFS, SEATTLE.
TREE STATUS (10 BEST)
TOTAL LEAF PHOSPHOROUS VS. TREE STATUS
FOR DISEASED TREES OF MAGNOLIA BLUFFS
y = 0.0079x - 1.0481
R2 = 0.3521
8
6
4
2
0
200
400
600
800
1000
1200
BRAY PHOSPHOROUS (MICROGRAMS/GRAM)
THERE IS NO CORRELATION WITH PHOSPHOROUS
AND TREES FROM THE HEALTHY BROADLEAF
FORESTS SINCE MOST TREES ARE RATED BETWEEN 8
AND 9.
CONCLUSIONS
• MADRONE HEALTH IS A FUNCTION OF
SOIL STRUCTURE AND NUTRITION.
• MADRONES ARE AFFECTED MORE
EASILY BY DISRUPTION OF THE
EPIPEDON THAN OTHER URBAN TREES.
• THIS IS ONE OF SEVERAL REASONS FOR
THE URBAN DECLINE OF PACIFIC
MADRONES IN THE PNW.
THE END
Variation in Soils
• Successional trends from Fort Lewis
• Variation associated with series and
structure
Healthy Tree Micronutrient
Phenological Variation of Leaves
• B and Ni vary due to
detection limits set
with ICP
• Fe is higher in all
ages, but varies as
does Cu
• Zn and Mn are stable
at all levels
• Mo was not detected
PARTS PER MILLION
Annual macronutrient variation
in leaves on a healthy tree (GSC)
GSC98
GSC99
GSC00
12000
10000
8000
6000
4000
2000
0
Ca
K
Mg
P
S
MACRONUTRIENTS OF HEALTHY LEAVES .
• Ca and S increase, the
others decrease with
time
• Mobile elements are
highest in youngest
leaves
• K is highest in young
leaves
GSC_LF_PHENOL
Ca
1
2
3
4
5
6
7
9
10
11
12
K
Mg
2359
2665
2424
2522
2575
2672
2513
2558
2404
3117
2712
9420
10235
9052
8965
9059
9887
8047
9010
9706
9659
10551
844
1076
916
931
894
958
885
808
950
868
877
P
S
2507
2852
2468
2479
2448
2788
2513
2416
2546
2316
2742
%N
991
1180
924
1019
969
1075
1018
905
1018
945
1768
1
2
3
4
5
6
7
9
10
11
12
%C
2.13
2.28
2.34
2.26
2.6
2.15
2.4
1.95
2.06
2.23
2.17
B
48.34
47.56
48.22
48.6
47.52
48.13
47.87
47.8
47.6
48.11
48.01
1
2
3
4
5
6
7
9
10
11
12
Cu
1
18.4
15.8
16.6
1
16.7
16.8
1.0
1.0
16.3
16.9
Fe
6.6
7.1
23.2
11.4
9.1
18.1
9.9
5.0
6.4
5.0
6.3
Mn
Mo
86
214
75
40
52
52
88
43
89
36
232
17.3
18.7
13.5
14.0
14.1
14.8
14.9
13.6
14.7
13.7
15.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
100
12000
Ca
K
Mg
P
S
8000
PPM
%LEAF DRY WEIGHT
10000
6000
4000
10
2000
0
1
1
2
3
4
5
6
7
9
10
11
12
1
YOUNG TO OLD (2000)
12000
10000
% DRY WEIGHT
PPM
6000
4000
10
2000
1
0
GSC98
GSC99
GSC00
80
70
60
Ca
K
Mg
P
LEAF MACRONUTRIENTS
S
%N
3
4
5
6
7
9
YOUNG TO OLD (2000)
100
8000
2
98
99
0
YEAR LEAF DEVELOPED
%C
1000
10
11
12
BACKGROUND
Pacific madrone (Arbutus menziesii) is in decline in urban
areas of the Puget Trough.
This Puget Sound region
is
characterized by young glacial soils of mixed mineralology and
texture. Associated with the decline of madrones is infestation by
fungal pathogens that most likely are of native origin. The slow
demise or death of the madrones occurs over a time period of years
or even decades suggesting that plant nutrition, habitat or root
function may play a role in the pathology of this plant. In other
well-known tree/fungal pathogen interactions, death of the tree host
is abrupt and certain. Such is the case with the American chestnut,
Dutch elm and more recently oak infestations California.
From the standpoint of pathology and co-evolution this tree is
most interesting to study. This is especially true when soils are
considered as a factor in pathology. Phytophthora (root rot) seems
to infect roots in soil of poor drainage. Fungal hyphae move
rapidly into the vascular tissue of the plant and young saplings at
least die within weeks of the infection. Death occurs for the top of
the plant downward. This sudden death results in leaves remaining
on the plant after death, thus providing a field method for
identifying the disease. Soils with poor drainage are more likely to
have trees that die young with Phytophthora.
Nattrassia mangiferia, on the other hand, infects the stem as a
surficial depression of the bark. The fungus grows actively from
the circumference of the depression leaving a black hollow hole
behind. Although this fungus directly takes nutrients from the
plant, it also damages its host indirectly by girdling branches thus
denying transport of water and soil nutrients to the leaves and sugar
products of photosynthesis from the leaves to the roots. Unlike
Phytophthora, madrone trees often coexist with Natrassia cankers;
in some cases, they even reverse the spread of disease. On many
urban soils and natural soils in which topsoil has been removed or
modified, nonetheless, the Nattrassia fungus has slowly decimated
some madrone populations.
Annual Micronutrient Variation in
Leaves on a Healthy Tree (GSC)
80
PARTS PER MILLION
• Micronutrients
increase or remain
constant on an annual
basis
• Fe, B and Zn are
higher than Cu, Mn,
Mo and Ni
• Cu levels are constant
70
GSC-98
60
GSC-99
50
GSC-00
40
30
20
10
0
B
Cu
Fe
Mn
Mo
MICRONUTRIENTS
Ni
Zn