David Granatstein

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Orchard Floor Management
David Granatstein
WSU Center for Sustaining Agriculture and Natural
Resources Wenatchee, WA
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Orchard Floor Management Functions Impacted
by Water intake/storage Understory
species Physical support Understory canopy Gas
exchange for roots Irrigation system Nutrient
cycling/storage Nutrient inputs Habitat (micro,
macro) Spray drip Micro-climate Organic inputs
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Orchard Floor Management Review Microclimate ?
soil temperature inverse to the amount of herbage
or mulch ? plant mulch dampens extremes of
daily soil temperature ? plant cover reduces
minimum air temperature by 0.5-1.0oC ? bare,
compacted wet soil raised minimum air temperature
by as much as 2oC ? dwarf rootstocks grow
best at 14oC vs. up to 27oC for seedling
rootstocks (Skroch Shribbs, 1986)
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Orchard Floor Management Review Soil quality ?
avoid cultivation ? favorable soil effects
legumes grass mulch bare ground
cultivation Water ? soil moisture availability
mulch bare soil minimal cultivation
grass legumes continuous cultivation ? mowing
decreases water use (Skroch Shribbs, 1986)
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• SOIL
• Complex, dynamic living medium as indispensable
  to plant growth as sunlight and air.
• Civilizations have fallen throughout history due
  to failure to maintain the quality of soils.
• Source and medium of delivery of most water and
  nutrients for plants.
• Defined by its physical, chemical, and
  biological properties..

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SOIL QUALITY Definition Capacity of a soil
to function within ecosystem boundaries
to ? sustain biological productivity ?
Maintain environmental quality ? promote plant
and animal health. Not a soil property,
but a value based on human needs. Soil health and
quality are used interchangeably.
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Soil Quality

• Chemical
• Biological Physical
• Dynamic interplay of 3 aspects
• Short-term and long-term changes
• Influenced by environment (climate, geology,
  plants)
• Influenced by human activity (erosion,
  fertilization, irrigation, plants)

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Soil Quality Reference Point
Current System Native Ecosystem Reference
Point Dryland wheat (KS) Prairie Prairie  Rainf
ed corn (WI) Temperate forest
Pasture ? Paddy rice (Asia) Tropical
rainforest ?? Irrigated potatoes (ID)
Shrub-steppe Pasture ? Orchard
(Yakima) Shrub-steppe ??
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INDICATORS OF IMPROVED SOIL QUALITY Increasing
Decreasing Infiltration Bulk
density Aggregate stability Soil
resistance Macropores Runoff Aeration Erosi
on Biological activity Nutrient
losses Water-holding capacity Diseases Soil
organic matter Production costs
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Carbon the key ingredient
Carbon (C), the basis of Soil Organic Matter,
which affects Physical bulk density, aggregate
stability, water-holding capacity Chemical
cation exchange capacity, nutrient
release Biological energy source for microbes,
base of the soil food web, nutrient turnover,
soil-borne diseases
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SOIL ORGANIC MATTER Friends Enemies No-till
Tillage Mulching Erosion Organic
amendments Fumigation Cool temperatures Herbicid
es, bare ground Nutrient balance Leaching,
nutrient export
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Carbon Budget Inputs Crop residues leaves,
roots, prunings Green manures Animal
manures Imported organics compost, yard debris,
etc. Losses Background soil respiration Tillage
accelerated mineralization Erosion wind,
water Crop export roots Burning
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Soil Quality Testing
Chemical Biological Physical Integration Soil
Quality Index
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Testing Approaches
Soil physical, chemical, biological  Plant
bioassay  Ecosystem watershed, energy,
diversity
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Soil Quality Index Orchard Systems Four soil
functions (after Karlen et al., 1994) ??
Accommodate water entry (weight 0.20) ??
Facilitate water transfer and absorption (weight
0.20) ?? Resist degradation (weight 0.20) ??
Sustain fruit quality and productivity (weight
0.40) (Glover et al., 1998)
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Soil Quality Index Function Accommodate water
entry Weight Indicator Infiltration
0.40 Aggregate stability 0.30 Surface
bulk density 0.20 Earthworms 0.10 (Glover
et al., 1998)
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Soil Quality Index Function Facilitate water
transfer and absorption
Weight Indicator Water filled pore
space 0.40 Porosity (0-15 cm) 0.30 Organic
C (0-15 cm) 0.15 Earthworms 0.15 (Glover
et al., 1998)
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Soil Quality Index Function Resist
degradation Weight Indicator Aggreg
ate stability 0.60 Microbial
processes 0.40 (Glover et al., 1998)
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Soil Quality Index Function Sustain fruit
quality and productivity
Weight Indicator Rooting environment 0.27 Wate
r relations 0.27 Nutrient relations 0.26 C
hemical barriers 0.20 (Glover et al., 1998)
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Soil Quality Index for 1998 WSU Orchard Systems
Trial Zillah, WA Orchard
System Function Conventional Integrated
Organic Water entry 0.09 0.14 0.17 Water
transfer 0.17 b 0.19 a 0.17 b Resist
degrad. 0.14 b 0.20a 0.16 ab Sustain
product. 0.13 b 0.34 a 0.36
a Total 0.71 b 0.87 a 0.86 a (Glover
et al., 1998)
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WSU Orchard Systems Trial - Zillah, WASoil
Organic Matter Content (0-15 cm)
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Soil Biology
The last frontier ? The ultimate black box ?
Microbe - Microbe Microbe - Macrofauna Microbe -
Plant
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Effect of Apple Replant Disease Gala/M26,
Moxee, WA
Replant soil Virgin soil
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Growth of Gala Apple Seedlings in Soil from
Orchard Blocks of Varying Age
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Changes in Relative Recovery of Specific
Microorganisms with Increasing Age of WVC Orchard
Blocks
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Cover Crops and Fallow No change in disease
pressure with one-year fallow Wheat cover crops
effective in reducing Rhizoctonia, Pythium,
Pratylenchus penetrans inducing microbial
shifts and enhancing tree seedling
growth Effect of wheat is very
cultivar-specific Rapeseed cover crop moderately
effective, but soil amendment with rapeseed meal
is promising
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Growth of Gala Apple Seedlings in CV Orchard
Replant Soil Following Planting with Different
Wheat Cultivars
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Other Cultural Controls Autumn trenching nearly
as effective as soil fumigation Planting new
tree rows in former drive aisles also
effective Alternating between apple and
non-susceptible perennial crop (e.g.
cherry) Plant more resilient or vigorous
rootstocks
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Trench Control
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Recovery of Fungi from Apple Roots at CV Orchard
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Organic Amendments
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Evaluating Compost Quality for Orchard Use
What end use?  Absence of contaminants  Maturity  
Moisture content  Organic matter  Electrical
conductivity (EC)  pH  Total N  Available N
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Nutrient Content of WA Composts
Parameter Chicken (3) Cow (4) Yard
(3) Org. Matter () 4-78
30-50 30-50 pH 6.3-8.3 6.1-8.9 6.3-7.6 E.C.
(mmho/cm) 25-30 7-25 2-13 CN
10-38 10-32 13-23 Total N () 1.1-4.2
0.9-1.9 0.8-2.0 NO3-N (ppm) 162-2460 36-2081
8-1421 NH4-N (ppm) 3600-9780 16-306
17-50 Total P () 0.9-1.8 0.2-0.8
0.2-0.3 Total K () 0.6-2.5 0.3-1.4
0.4-1.1 (Granatstein, 1996)
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Comparison of Testing Labs
Mean Range C.V. pH Chicken 6.6
5.7 7.7 10 Yard 6.9 6.5 7.3
5  E.C. Chicken 25 14 38
34 (mmho/cm) Yard 7 4 11
36  Total N Chicken 3.6 2.9 4.2
12 () Yard 1.2 0.9 1.4
16  NH4-N Chicken 8620 6700 10500
19 (ppm) Yard 370 17 -
1400 158    Low C.V. pH, total N, total P,
organic matter
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Compost Costs
/wet ton /wet ton /dry ton
/lb N FOB Freight
Delivered dry Chicken manure
40 30 107 1.31   compost Dairy manure
24 17 80 1.74   compost Yard debris
14 26 70 2.69 compost
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Nutrient Value of Compost
Value /wet ton Total Availabl
e Nutrient Nutrient Chicken manure
compost 41-53 13-14 (4 total N) Yard
debris compost 20-23 5 (2 total
N)   Includes N, P, K, Ca, S, Zn (37lb N
40-90/lb P 21/lb K 9/lb Ca 11/lb S
1.40/lb Zn) Based on fertilizer prices of 2/98.
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Organic N Sources and Costs
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Disease Suppression with Compost

• Need sufficient organic matter to support
  microbial growth/activity
• General Suppression occurs as compost matures
  and limits readily available substrate effective
  on Pythium, Phytophthora
• Specific Suppression requires colonization by
  microbial antagonists of pathogen needed for
  Rhizoctonia
• Suppressive ability hard to predict in terms of
  range and longevity of control influenced by
  compost feedstocks, production process

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Effect of Compost on Trunk GrowthNew orchard
sites - 3 year cumulative
P 0.04 R2 0.22
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Foliar Disease Control with Compost Tea Oregon,
1996
No Water Compost 
Best Crop/Disease Trt Control Tea
Fungicide   - - - - - - infection or
infestation - - - - - -  Apple/Scab
Leaves 41 -- 40 13 Fruit 52 -- 37 11  C
herry Blossom blight 11 -- 6 3 Cherry
leaf spot 62 -- 42 5  Grape/Powdery Mildew
Leaves -- 25 19 8 Clusters -- 25 17 10
  (H. Wittig, 1997)
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Compost Tea and Pathogens
 Can Human Pathogens Grow In Compost
Tea? Addition of molasses led to Salmonella
growth (3 log or more) No growth without
molasses Tea sprayed on strawberry plants,
pathogens grew on leaves   (B. Duffy, USDA-ARS)
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Orchard Mulching and Cover Crops
Weed control non-herbicide suitable for
organic production Moisture conservation Fertility
management, soil quality Pest management ?
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Orchard Cover Crops Purposes ?? Prevent
erosion, dust ? Reduce effects of equipment on
compaction ?? Improve soil quality and nutrient
cycling ? ?Improve orchard IPM
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Orchard Cover Crops A good cover crop ?
Limited competition with the tree ? Poor
habitat for rodents, other pests ? Good habitat
for beneficial species ? Improves soil quality
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Area and Timing of Weed Control New
York Imperial Gala/M.26 Weed-free Cum.
Yield Cum. Growth area (ft2) (kg/tree)
TCSA (cm2) 0 14.9 20.0
22 41.0 25.5 43 38.2
25.6 65 41.1 24.7 LSD(.05)
11.0 5.1 Planted in 1991 cumulative
data for 1991-1995. (Merwin Ray, 1997)
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Area and Timing of Weed Control New
York Imperial Gala/M.26 Weed Control
Time Cumulative Yield (days) (month)
(kg/tree) 0 check 15.0 30 May 34.4 30
June 34.5 30 July 30.7 30 August 36.6
60 Ma, Jn 46.3 60 Jn,Jy 42.7 60 Jy,
Au 40.5 90 Ma, Jn, Jy 51.9 90 Jn, Jy,
Au 46.0 (Merwin Ray, 1997)
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Costs of Orchard Weed Control New York
Cost (US/acre/yr) System Materials Labor
Total Hay-straw mulch 300-400
145 300-550 Wood chip mulch 0-20
295 130-315 Weed collarTM 9800 200
10,000 1.2 mil polyethylene 150 35
185 Belton-Sarlon plastic 735
35 190-770 Warrens Weed-arrestTM 1800
35 395-1835 Herbicide strip 10
5 15-50 Mowed sodgrass 30 40
70-100 Clean cultivation 15 35
50 cost based on 1-4 yr life of
material (Merwin, 1995)
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Orchard Floor Management New York Soil Changes
Over 5 Years SOM NO3-N
P K Treatment (g/kg soil) (kg/ha)
(kg/ha) (kg/ha) Mowed sod 5.6
6.3 5.7 209 Straw mulch 6.2 37.6 28.5 12
30 Glyph. 5 strip 4.9 8.3 6.4
201 Tilled 4.5 53.2 4.7
188 LSD(.05) 1.0 30.1 12.0 163 (Merwin
Stiles, 1994)
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Effect of Orchard Floor Management on Tree
Mortality After 6 Years - New York
(Merwin Stiles, 1994)
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Wood chip mulch, Wenatchee, WA.
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Shredded paper mulch, Wenatchee, WA
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Fall-planted Dwarf white clover
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Fall-planted Oriental mustard
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Spray-on paper mulch
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Orchard Mulching Trials Summerland,
BC Bulk Density biosolids treatments 0.92 vs.
check 1.51 Moisture Retention biosolids,
composted biosolids sign. check Soil
Temperature maximums lower under mulches,
except greatest (10oC) under geotextile Infiltra
tion Rate inhibited by geotextile all other
mulches sign. check
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Orchard Mulching Trials Summerland,
BC 5th Leaf Spartan / M.9 TCSA
Roots Yield (mm2) (g/0.018m3)
(kg/tree) 1. Check (glyphosate) 1011 b
11.3 c 10.3 c 2. Biosolids (Vancouver) 1052
b 16.9 bc 11.2 bc 3. Paper mulch 1565 a
28.7 abc 13.0 ab 4. 2 3 1490 a
41.8 a 13.9 a 5. Composted biosolids 3 1406
a 38.7 a 14.9 a 6. Alfalfa hay 1203 b
35.2 ab 14.0 a 7. Geotextile 1125 b
19.1 bc 12.7 abc (Hogue et al., 2000)
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WVC Mulch Trial
Treatments compared to Control 3-yr
2-yr 2001 TCSA Yield Yld Eff. Alfalfa 63
40 60 (ns) Clover 30 35 130 Woodchip 2
6 0 105
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WVC Mulch Trial
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N Release from Clover Living Mulch
A Control Cover D Clover Cover
Clippings B Control Cover Clippings E
Control (no tube) C Clover Cover
Clippings F Clover (no tube)
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N Release from Clover Living Mulch
A Control Cover D Clover Cover B
Control Cover Clippings E Control (no
tube) C Clover Cover Clippings F Clover
(no tube)  
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WVC Mulch TrialWeed Biomass 9/99
9/21/99
b
a
a
a
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WVC Mulch TrialWeed Control by Mulches 6/1/00
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Effect of Mulches on Nematodes in Orchard Soil -
Summerland, BC
(Hogue et al., 1998)
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Pest Reduction with Cover Crops Cover crops can
control tree vigor through regulation of N and
water. Apple (WV) lower aphid populations in
trees with cover crop than with herbicide strip
also 50 less powdery mildew, slightly less scab,
and no fireblight with lower vigor (Brown
Schmitt, 1996) Apple (BC) much less aphid
infestation with white clover/grass cover vs.
rye, herbicide strip, weed barrier clover mix
competed with trees, reduced vigor, which reduced
aphids (Haley Hogue, 1990)
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Pest Reduction with Cover Crops Successful
examples usually involve a specific pest-predator
relation. Pecans (GA) control of pecan aphid
with convergent lady beetle grow cover crop of
hairy vetch produced two generations of lady
beetles, reaching 143,000/acre migrated from
ground cover (senescing) to pecan trees at time
when aphids are reaching peak levels effective
biocontrol achieved (Tedders, 1983) Citrus
(China) control of citrus red mite by natural
enemies (Amblyseius spp.) encouraged on the weed
Ageratum conyzoides cover is planted or
conserved used on over 135,000 ha of citrus
(Liang Huang)
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Cover Crops in Apples Royal City, WA Pest /
beneficial ratios 3 best 3 worst Bug n
Breakfast Mix 5.6 Grass B3 31.8 Special
Insectary 6.2 Grass BP 17.9 Special
cover 7.0 Grass B1 14.6 (Granatstein, 1995)
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Effect of mowing on insect fauna in pears Hood
River, OR
Spiders
Floor
Harvestmen
Unmowed
Monthly
Density (ratio to weekly mowing)
(Horton, 1998)
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Effect of mowing on insect fauna in pears Hood
River, OR
Floor
Unmowed
Monthly
Density (ratio to weekly mowing)
(Horton, 1998)
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Effect of mowing on insect fauna in pears Hood
River, OR
Floor
Unmowed
Monthly
Density (ratio to weekly mowing)
(Horton, 1998)
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Effect of mowing on insect fauna in pears Hood
River, OR
Tree
Unmowed
Monthly
Density (ratio to weekly mowing)
(Horton, 1998)
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Effect of mowing on insect fauna in pears Hood
River, OR
Tree
Unmowed
Monthly
Density (ratio to weekly mowing)
(Horton, 1998)
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Effect of mowing on insect fauna in pears Hood
River, OR
Floor
Unmowed
Monthly
Density (ratio to weekly mowing)
(Horton, 1998)
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Enviroscan Mulch Trial
An automated system that continuously measures
soil moisture content.
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Enviroscan probe
Individual sensors
Access tube
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WVC Enviroscan Results
Mulch
No mulch
Wood chip mulch led to 20-25 less moisture
depletion between irrigations.
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Summerland, BC - Cumulative Water Use
1200
1000
800
L H2O used (15/06 to 23/08)
600
400
Mulch
No mulch
200
0
0
5
10
15
20
25
30
35
40
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Trunk Diameter (mm)
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Mulching Summary

• Moisture monitoring alone reduced irrigation
  frequency by 50
• Mulching reduced moisture depletion another
  20-25 on established trees
• Mulches can provide adequate weed control
• Low-cost approaches are needed to make mulching
  practical

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Good Bets for Soil Health ? Reduce tillage,
stop erosion, maintain soil structure ? Keep
the soil covered ? Maintain adequate C, N
inputs ? Promote diversity, rotate crops ?
Monitor soil moisture to avoid excess
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• Knowledge Gaps
• Pest ecology in complex systems
• Pest / nutrition interactions
• Manipulation of rhizosphere
• Chemical ecology of plants
• Nutrient flow through orchard

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• Orchard Floor Management
• Net effect is the interaction of
• plant species
• management
• nutrient levels
• pests
• weather
• irrigation
• Harder to predict single component impacts.