How Can I Improve My Soils? Nutrient Deficiencies and Fertilization Rob Harrison, PNW Stand...

How Can I Improve My Soils? Nutrient

Deficiencies and Fertilization

Rob Harrison,

PNW Stand Management Cooperative

http://www.forestsoils.org/

Covered today

1) Tree nutrition

2) Nutrient limitiations

3) Risk-rating soils for biomass/nutrient removal

4) Fertilization to maintain/enhance fertility

5) Identifying nutrient deficiency

6) BMP for maintaining or enhancing soil fertility

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.

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

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

Nutrient Content of DF tissue

Tree component Nutrient content (%) N P K Ca Mg

Foliage 1.40 0.21 0.85 0.45 0.11Bark 0.29 0.07 0.31 0.42 0.13Cones 0.65 0.13 1.26 0.06 0.10Branches 0.36 0.07 0.21 0.51 0.05Bole 0.08 0.01 0.05 0.10 0.05

Sources of Nutrients

• Weathering

• Nitrogen fixation

• Atmospheric additions

• Mineralization

• Fertilization

SOILSOILSUPPLYSUPPLY

POTENTIAL USEPOTENTIAL USE

ACTUAL USEACTUAL USE

REMOBILIZEDREMOBILIZED

UPTAKE FROM SOILUPTAKE FROM SOIL

Nutrient Supply and Use

Source: Forest Nutrition Cooperatie

Essential Elements

Slide

foliar nutrient concentration

visual deficiency

hidden hunger

critical point (90% of max)

maximum growth "luxury" consumption

toxicity

deathRobHarrison:growth vs. nutrient conc

Rel

ativ

e gr

owth

Covered today

1) Tree nutrition






Regional Long-term Site Productivity StudiesMineral Soil Carbon and Nitrogen to 0.6 m depth:

13

Boistfort Grove

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)

14

Nitrogen Risk Ratings - Generalized Concept

15

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

= T

A =

S =

Evans, J.1999. Sustainability of forest plantations—the evidence. A review of evidence concerning the narrow-sense sustainability of planted forests. Report for the Department for International Development, London, UK. 64 p.


16

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

= T

A =

S =


17




0.1 0.3 0.5


A / T = 1300 kg N /ha / 14500 kg N/ha = 0.09

= T

A =

S =


18

Proportion of N pool removed:



0.1 0.3 0.5

Example 2: Matlock LTSP, Grove series

A / T = 605 kg N /ha / 3705 kg N /ha = 0.16

= T

A =

S =


19

Proportion of N pool removed:



0.1 0.3 0.5

Example 2: Matlock LTSP, Grove series

A / T = 605 kg N /ha / 3705 kg N /ha = 0.16

= T

A =

S =

Covered today

1) Tree nutrition






Diagnoses of Nutritional Requirements

Daignostic indicators of deficency symptoms Foliage deficiency symptoms Foliage and soil analysis

Nutrient uptake rates

Covered today

1) Tree nutrition






Percent volume response

N rate (lb N/acre)

N200 N300

N200-P88-S154

N200-P88-S168+

N100

N52-P12-K220

Percent volume response

N rate (lb N/acre)

N100

N52-P12-K220

N300N100

N200-P88-S154N200-P88-S168+

N200

N52-P12-K220

N+P

Installations of the PNW Stand Management Cooperative

SILVICULTUREWOOD QUALITY

NUTRITION

MODELING

College of Forest ResourcesUniversity of WashingtonBox 352100Seattle Washington 98195-2100

206-543-5355 phone206-685-3091 fax

RFNRP Installations

Forest floor C/N ratio

Percent Difference in Volume Increment vs Total Nitrogen Fertilizer Applied

0

10

20

30

40

50

60

70

200 400 600 800 1000

Total N Fertilizer Applied (lb/ac)

II

III

IV

V

Site Class:

II : 120-140 ft

III : 100-120 ft

IV: 80-100 ft

V : < 80 ft

Overall results of SMC studies Response vs. N rate. Sidell thesis.

(1)

Results of RFNRP studies

1) N response averaging 20% (unthinned) -30% (thinned) with 400 kg N, highly site dependent.

2) 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.

3) Effects of N fertilization appear to be very long-lived.

Covered today

1) Tree nutrition






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

Estimating forest productivity and potential for response to

fertilization: SMC/CIPS paired-tree fertilization project

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

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

sedimentary

glacial

igneous

Soil Nitrogen

Covered today

1) Tree nutrition







50




0.1 0.3 0.5


A / T = 1300 kg N /ha / 14500 kg N/ha = 0.09

= T

A =

S =

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.

How Can I Improve My Soils? Nutrient Deficiencies and Fertilization Rob Harrison, PNW Stand...

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