Post on 08-Feb-2020
Soil, Soil, Toil and Trouble
What Lurks Beneath
Dr Glynn Percival
Bartlett Tree Research Laboratory
R&D Lab – Charlotte USA
Bartlett Tree Research Laboratory,
University of Reading Clients
SITES Clients
Dying Trees and Shrubs
Box blightSymptoms of box blight
Where do you start?
Soil Sampling
Soil
nutrient
analysis and
prescription
fertilisation
FERTILISERS
Modes of application
Percolation test
Drainage Analysis
Soil profileSOIL COMPACTION
EVALUATION
Decompact
End resultBefore After
Soil
nutrient
analysis and
prescription
fertilisation
Boron Contaminated Soils
So how do you remediate soils high in boron and heavy
metals?
Puccinellia frigida
Strategic Planting of Accumulator Plants
Heavy Metal Removal (mg/Kg of soil ) By Accumulator Plants
2015 2016 2017
Boron 19.0 17.1 15.8
Copper 9.2 8.8 8.3
Zinc 80.4 77.4 72.5
Three aspects of soils1. Chemical: pH, macro and micronutrients
2. Physical: Structure/compaction/silt:sand:clay
ratios
3. Biological: Soil is a very complex “living organism”
There are more microorganisms in a handful of soil
than there are people on earth.
Soil is at the bottom of the food chain, yet it is the cornerstone of life on earth.
Testing for soil biological activity
Worm test: 0-2 = Low biological activity
2-4 = Medium biological activity
5-8 = Acceptable biological activity
9-10 = High biological activity
Honey Fungus
.
0
1
2
3
4
5
6
RCX Control RCX Control
Co
nd
itio
n R
ati
ng
(1-5
)
Vineyard 1Vineyard 2
Plant condition higher in RCX treated vines
Baumgartner K (2004) Plant Disease 88:1235-1240. RCX + Biochar
A purified form of charcoal.
When added to soil it:
Increases CEC
Improves water retention
Improves fertiliser effectiveness
Soil Management –
Biochar
Benefits are now realised.
BiocharOrganic material pyrolysedat temperatures in excess of 350°c
Biochar
Vinca and Gardenia inoculated with Phytophthora
Control Compost Biochar
Acts as a haven for mycorrhiza
Slides courtesy of J MacPhail
Mycorrhizae trapping nematodes with their filamentous hyphae
Slides courtesy of J MacPhail
Biochar effect on leaf blotch and leaf miner severity
GrowChar
0.25kg m2
GrowChar 0.50kg m2
Control
Bio-Control - Trichoderma
Fungi in the genus Trichoderma have been recognised since
the 1920s for their ability to act as bio-control agents against
both root and foliar plant pathogens. When added to the soil
and come into contact with tree roots, Trichoderma rapidly
colonize the root surface or cortex, depending on the strain. In
addition to colonizing roots, spp. attack, parasitize and gain
nutrition from other fungi.
RCXApply Trichoderma
Protect the root collar
Use of physically inert compounds such as perlite, vermiculite, sand etc., that are suitable for root but not rhizomorph growth and development.
Question. What makes a successful disease a successful disease?
Plant Defence Activators (PDA’s) PDA’s “switch on” a plant's own defence mechanisms by
treatment with either a biological or chemical agent.
Commercially available PDA’s.Messenger (a.i. Harpin protein) in the US.Bion (BTH) in Europe.Agri-Fos (a.i. Potassium phosphite) in Australia and the US .Rigel (a.i. Salicylic acid analog) in the UKOryzemate (a.i. Probenazole) Japan.
Changes in tree physiology:
1. Accumulation of antimicrobial proteins, fungi-toxic
derivatives and antimicrobial fatty acid.
2. Increase in plant antibodies (phytoalexins)
3. Leaves become thicker and more resistance to
enzymatic degradation
4. Enhanced resin production, synthesis of new
phenolics and initiation of a wound periderm.
5. Alteration of the topography of the leaf surface thus
interfering with fungal recognition of host
penetration sites
Control
Fungicide
Messanger
Control
Fungicide
MessangerResults of several
years of trials show
PDA’s can reduce
disease severity by 60-
70%.
Mulching
Research Plan
Experiments used containerized stock of horse
chestnut (Aesculus hippocastanum) – highly
sensitive to Phytophthora root diseases.
Inoculation
Each potted plant was inoculated with twelve rice grains colonized
by P.cactorum.
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Control F.sylvatica Q.robur Q.ilex P.avium B.pendula C.monogyna
Dis
ease s
everi
ty
The influence of pure mulches on disease severity of Phytophthora root rot
***
***
Willow mulchNo mulch Willow mulch
Number Trees Re-Infected
0
1
2
3
4
5
6
7
8
Control Treated
Improvements in Tree Health
Oak Processionary Moth –
Dangerous to humans
My favourite tree
Thank
You