Abiotic Module 5

What is compacted soil

soil particles pressed together, reducing water infiltration and drainage, less exchange of gases, more difficult for roots to penetrate

Effects of Soil Compaction on Plants

lodging, roots less able to exploit soil, nitrogen, potassium and phosphorus deficiencies, additional fertilization, roots less able to get moisture and experience moisture stress

Soil Compaction Effects

root growth is limited and restricted at certain soil strengths, seed emergence will be delayed and variable, reduced permeability, decreased soil microbial activity, increased drought and/or water logging

Causes of Soil Compaction

Farm equipment, heavy pedestrian traffic, cultivating and walking on wet soil in gardens, compression by construction equipment, cars and trucks parked under trees, after construction projects, clay soils

What % of soil compaction tales place on the first pass

70-80%

How does farm equipment affect soil compression

farm size increase with tractors, tractors weigh more,

Crop lands effect on soil compaction

best management tool is prevention, controlling, avoid working wet soils, proper inflation, size of tires, reducing axle load

Managing soil compaction on crop land

controlled traffic, needs to be considered in equipment matches, consider narrow tires, axle loads above 10 tons each increases compaction

Measuring Soil Compaction with Steel Stake

steel stake-driven 18” deep in comparison areas, note how much effort needed to drive stake in the field, 7x

What is a comparison area?

soil that has not been tilled and has not received wheel traffic for years compared to representative area of the field where compaction is suspected

Soil Bulk Density Test

measures weight of dry soil per unit vol, calculates mass of solid soil particles within a given volume, higher bulk density=more compacted soil,

Factors that affect bulk density

soil texture, organic matter, soil structure, compaction from machinery or foot traffic

How is a Soil Bulk density test done

soil core is collected using a cylindrical sampler, volume is measured, soil is dried, weight is determined to calculate bulk density

Cone Penetrometer

device used in geotechnical engineering, measures resistance of soil by pushing cone shaped tip into ground, provides info about soil by recording force requires to penetrate at a constant rate

How to correct soil compaction

amend with compost, choose adapted plants, grow cover crops, grow deep rooted perennial grasses, aerate by removing small plugs, organic materials decompose, redial trench around established trees, replace soil, employ sub surface soil

Soil compaction can be good in what ways?

slightly compacted soils speed up rate of seed germination, moderate compaction reduces water loss

Terralift Soil Aerator

technician inserts a probe into the soil, compressed air is released through probe, air fractures the soil creating fissures

Black Layer of Turf

poor draining symptoms caused by dissimilar substrates

What are Girdled Roots

root that grows in a circular pattern around trunk at or below soil line, cuts off the flow of sap in the tree, limiting carbohydrates from moving through the phloem

Girdled Roots symptoms

reduced growth, lighter green leaves, scorched, show early fall color, early leaf drop, branch die back, splitting bark, thinning crown, stunted growth, one side of trunk is straight

Girdled Roots Causes

poor planting techniques, deep mulch, compacted soil, container-grown plants, transplanting, trees and shrubs that are container grown

Girdled Roots Treatment

container plants-loosen the roots and spread them out in the planting hole, remove mulch volcano to expose roots, use an air knife to remove soul while leaving roots intact

Kinked Roots

caused by improper transplanting, liner to pot or pot to ground

Differential Diagnosis Look- Alikes Kinked Roots

can be caused by drought or nutrient imbalances

Mechanical Injury: Tree Staking

best not to stake, trees establish themselves quite well normally, staking and guying can be detrimental, movement caused by wind helps saplings

When should you stake?

depends on environment and type of tree, bare root trees and container-grown trees, large evergreen trees with high wind, mechanical damage

Improper Staking

staking trees too high, too tightly, or for too long, cause stem abrasions and trunk girdling, review anchor, attachment point and tension,

Vehicular Damage

trunk wounds that penetrate the bark will damage the cambium layer, if less than 25% has been damage will recover, injured bark removed carefully

String Trimmers: Weed Whacker Blight

cuts into bark, creates an open wound, girdles on tree cut off trees water supply,

Other Types of Tree harm

Vandalism, Over-Pruning

What to prevent when pruning

development of low aggressive limbs, weak codominant stems, bark inclusions, formation of codominant stems and defects, topping trees and over lifting are harmful

Large Limb Removal

cut not at direct angle, removal of large branches, cavities cracks and cuts can result, most common unrecognized defects

Pruning Technique

dont cut flush to tree, dont leave stub, remove with saw, do 3 cuts to collar, dont cover wound

Damage Due to Landscape Modifications

size of planting space, trenching, surround with concrete or asphalt, soil compaction,

Cutting Structural Roots

symptoms of: lack of vigor and reduced growth, symptoms will appear on side of tree were roots severed, branch dieback, sparse leaves, leaf wilting and browning

What is Cambistat used for?

to control urban or RoW treets response to pruning,stress environments, and to manage size and roots, aid in tree drought tolerance

Whats normal for grafting?

normal building at the graft union

What are the causes of graft incompatibility?

graft incompatibility, improper teqnique, environmental conditions, result of genetic difference, disease, abnormalities

Symptoms of Graft Failure

smooth clean breaking of tree at the graft union, 1-2 years after graft, shoot die back, yellow foliage, early leaf drop, vegetative growth of scion and rootstalk, overgrowth,

Variegation Loss/Reversion

sport genetic mutation, only be propagated for vegetative means, will not come from true seed

Variegated Reversion Causes

genetics, stress, age, biotic organisms, prune out non variegated branches to prevent reversion

Phyllody

flower parts are replaced by leafy structures, pistils and stamens, common in roses plants in asteracea

Cause of Phyllody

hormone imbalance caused by environmental factors like drought stress, hot weather, water stress, and/or infection by viruses or phytoplasmas

Management of Phyllody

removal of deformed fruit or flowers to conserve root carbon reserves, foliage healthy or not indicates whether cause is abiotic or pathogens

What is Witches Broom

growth featuring highly congested shoots with shortened internodes, twigs bundled into a witch’s broom, wide variety of tree and shrub species

Witches Broom causes

genetic mutations, insects, disease, only caused by genetic mutation ca be propagated, not always stable and may revert

Witches Broom Cultivaton

genetic mutation vegetatively propagated, become dwarf conifers or other interesting attributes

Fasciation

abnormality that causes stems of flower heads to flatten, elongate or curve

Causes of Fasciation

genetics, injury, infection, pests, environmental

Genetic Fasciation

ribbon type, normally on stems but can be any part of plant, mutation can be transmitted vegetatively or through seed,

Bacterial Fasciation cause

rhodococcus fascians, occurs when multiple buds are formed that only partially expand, can occur below soil surface, at base of any plant, bacteria secretes cytokinins

Bacterial Fasciation are..

easily spread, eradication, sanitation