How Can I Improve My Soils? Nutrient Deficiencies and Fertilization

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How Can I Improve My Soils? Nutrient Deficiencies
and Fertilization

• Rob Harrison,
• PNW Stand Management Cooperative
• http//www.forestsoils.org/

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Covered today1) Tree nutrition2) Nutrient
limitiations 3) Risk-rating soils for
biomass/nutrient removal4) Fertilization to
maintain/enhance fertility5) Identifying
nutrient deficiency 6) BMP for maintaining or
enhancing soil fertility
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Table 1 US Timber trends. Data from Howard,
James L. 2003. U.S. timber production, trade,
consumption, and price statistics 1965 to 2002.
Res. Pap. FPL-RP-615. Madison, WI U.S.
Department of Agriculture, Forest Service, Forest
Products Laboratory. 90 p.
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outline
Tree Nutrition Nutrition of DF forests as
compared to annual plants Diagnoses of
nutritional needs of DF trees Sources of
nutrients in DF forest ecosystems Mechanisms by
which the nutritional needs of DF trees are
met Nutrient conservation retention processes by
forest ecosystems
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Advantages of Forests as a Perennial Plant System
Uptake can take place year around Internal
translocation of nutrients takes place Growth
of a tree builds on an existing structure
Nutrient loss from harvesting is significantly
less
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nutrients in D-fir
Nutrient Content of DF tissue Tree
component Nutrient
content ()
N
P K Ca
Mg Foliage 1.40
0.21 0.85 0.45 0.11 Bark
0.29 0.07 0.31
0.42 0.13 Cones
0.65 0.13 1.26 0.06
0.10 Branches 0.36
0.07 0.21 0.51 0.05 Bole
0.08 0.01 0.05
0.10 0.05
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Sources of Nutrients
Weathering Nitrogen fixation
Atmospheric additions Mineralization
Fertilization
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Nutrient Supply and Use
NUTSUPDM
POTENTIAL USE
SOILSUPPLY
ACTUAL USE
REMOBILIZED
UPTAKE FROM SOIL
Source Forest Nutrition Cooperatie
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Essential Elements
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Slide
Relative growth
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Covered today1) Tree nutrition2) Nutrient
limitiations 3) Risk-rating soils for
biomass/nutrient removal4) Fertilization to
maintain/enhance fertility5) Identifying
nutrient deficiency 6) BMP for maintaining or
enhancing soil fertility
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Regional Long-term Site Productivity
StudiesMineral Soil Carbon and Nitrogen to 0.6 m
depth

Boistfort
Grove
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Sustainable Soil Productivity Removals effects
on Nitrogen statusPotential Growth Reduction

• Bole-only harvesting removes 5 of N pool
• Total-tree harvesting removes 10 of N pool
• (after Johnson et al. 1982)

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Nitrogen Risk Ratings - Generalized Concept
Increasing risk of nitrogen (N) limitations as A
/ T proportion increases A Aboveground Total
N Pool (kg/ha) forest floor understory
vegetation standing crop S Soil Total N
pool (kg/ha) - rooting depth T A S

A
T
S
Evans, J.1999. Sustainability of forest
plantationsthe evidence. A review of evidence
concerning the narrow-sense sustainability of
planted forests. Report for the Department for
International Development, London, UK. 64 p.
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Nitrogen Risk Ratings - Generalized Concept
Proportion of site N pool removed Increasing
risk (after Evans, 1999) Low
Serious Imminent decline 0.1
0.3 0.5
Example 1 Fall River LTSP, Boistfort
soil A / T 1300 kg N /ha / 14500 kg N/ha
0.09
A
T
S
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Nitrogen Risk Ratings - Generalized Concept
Proportion of site N pool removed Increasing
risk (after Evans, 1999) Low
Serious Imminent decline 0.1
0.3 0.5
Example 1 Fall River LTSP, Boistfort
soil A / T 1300 kg N /ha / 14500 kg N/ha
0.09
A
T
S
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Nitrogen Risk Ratings - Generalized Concept
Proportion of N pool removed Increasing risk
(after Evans, 1999) Low Serious
Imminent decline 0.1
0.3 0.5 Example 2
Matlock LTSP, Grove series A / T 605 kg N /ha
/ 3705 kg N /ha 0.16
A
T
S

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Nitrogen Risk Ratings - Generalized Concept
Proportion of N pool removed Increasing risk
(after Evans, 1999) Low Serious
Imminent decline 0.1
0.3 0.5 Example 2
Matlock LTSP, Grove series A / T 605 kg N /ha
/ 3705 kg N /ha 0.16
A
T
S

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Covered today1) Tree nutrition2) Nutrient
limitiations 3) Risk-rating soils for
biomass/nutrient removal4) Fertilization to
maintain/enhance fertility5) Identifying
nutrient deficiency 6) BMP for maintaining or
enhancing soil fertility
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Diagnoses of Nutritional Requirements
Daignostic indicators of deficency symptoms
Foliage deficiency symptoms Foliage and soil
analysis Nutrient uptake rates
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Covered today1) Tree nutrition2) Nutrient
limitiations 3) Risk-rating soils for
biomass/nutrient removal4) Fertilization to
maintain/enhance fertility5) Identifying
nutrient deficiency 6) BMP for maintaining or
enhancing soil fertility
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N200
N300
Percent volume response
N200-P88-S154
N200-P88-S168
N100
N52-P12-K220
N rate (lb N/acre)
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NP
N200-P88-S168
N200-P88-S154
N100
N100
N300
N200
Percent volume response
N52-P12-K220
N52-P12-K220
N rate (lb N/acre)
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Installations of the PNW Stand Management
Cooperative
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RFNRP Installations
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RFNRP Installations
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Forest floor C/N ratio
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(1)
Overall results of SMC studies Response vs. N
rate. Sidell thesis.
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• Results of RFNRP studies
• N response averaging 20 (unthinned) -30
  (thinned) with 400 kg N, highly site dependent.
• Clearly, both response to N and other nutrients
  is site controlled. Indicates need for larger
  scale studies on a wide variety of sites to pin
  response to site variables.
• Effects of N fertilization appear to be very
  long-lived.

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Covered today1) Tree nutrition2) Nutrient
limitiations 3) Risk-rating soils for
biomass/nutrient removal4) Fertilization to
maintain/enhance fertility5) Identifying
nutrient deficiency 6) BMP for maintaining or
enhancing soil fertility
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Nutrient Deficiency Levelssolution cultures
(Walker and Gessel 1991)
Element Douglas-fir Hemlock WR Cedar
Sitka Spruce Abies
1.8 0.25 1.1 0.18

• Nitrogen
• Phosphorus
• Potassium
• Calcium
• Magnesium
• Sulfur

1.25 0.16 0.6 0.25 0.17 0.35
1.5 0.13 0.6 0.20 0.12 0.4
1.8 0.09 0.4 0.06 0.06 0.15
1.15 0.15 0.50 0.12 0.07
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Estimating forest productivity and potential for
response to fertilization SMC/CIPS paired-tree
fertilization project
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Hypotheses

• Soil and other will predict Douglas-fir response
  to N fertilization
• Soil bulk density, porosity and texture
• Soil organic matter and nutrient pools
• Climate and soil temperature
• Precipitation and soil moisture
• Site index
• LAI
• Elevation, slope and slope position
• Aspect
• Stand stocking, type and development

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Current Paired Tree Trials

• 6 sites installed winter 2007
• 28 sites installed summer 2008
• 2 sites ready spring 2009
• Scouting more to fit into matrix

glacial
sedimentary
igneous
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Soil Nitrogen
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Covered today1) Tree nutrition2) Nutrient
limitiations 3) Risk-rating soils for
biomass/nutrient removal4) Fertilization to
maintain/enhance fertility5) Identifying
nutrient deficiency 6) BMP for maintaining or
enhancing soil fertility
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Nitrogen Risk Ratings - Generalized Concept
Proportion of site N pool removed Increasing
risk (after Evans, 1999) Low
Serious Imminent decline 0.1
0.3 0.5
Example 1 Fall River LTSP, Boistfort
soil A / T 1300 kg N /ha / 14500 kg N/ha
0.09
A
T
S
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Conclusions

• - Nitrogen commonly limits forest productivity in
  PNW
• - N-fertilization of forestlands of the Pacific
  Northwest is an important treatment resulting in
  higher productivity
• - Low sites show the highest response, high
  sites the lowest. Higher rates result in higher
  response.
• Interestingly, N fertilization seems to have
  long-term effects on new stands, but we have
  limited data on this.
• Our ability to predict response stand-by-stand is
  quite limited.