Forest Nutrient Research: Past, Present & Future

Forest Nutrient Research:

Past, Present & Future

Mark Kimsey

IFTNC 2012 Annual Meeting

Moscow, ID

Overview

• Context – The Basics

– Plant Essential Nutrients – Role in Plant Development

– Origins of Forest Nutrition Research

• IFTNC: The First Decades

– A Blank Slate

– Nutrition & Forest Productivity – Diagnostic Tool Development

• Current Nutrient Research

– Applying Lessons from the Past – Future Forest Productivity Study

• The Future of Nutrient Monitoring

Plant Essential Nutrients

& Primary Source

Macronutrients (<100 ppm)

• Nitrogen - Atmosphere

• Phosphorus - Rocks

• Potassium - Rocks

• Sulfur – Atmos., Rocks

• Calcium - Rocks

• Magnesium – Rocks

Micronutrients (<100 ppm)

• Boron - Rocks

• Copper - Rocks

• Zinc - Rocks

• Iron - Rocks

Role of Soil Nutrients in Plant Growth

• N – Growth proteins

• P/S/Mg/Cu/Fe – Photosynthesis

• K – Water regulation

• Ca/B – Nutrient transport

• Zn – Enzymatic production /DNA

transcription

Founders of Modern Forest Nutrition Research

Johann Heinrich Cotta (1763-1844)

Est. 1811 - Royal Saxon Forestry Academy

Karl Leberecht Krutzsch (1772-1852)

Rock and Soil Science

for Forestry and Agriculture - 1827

Inland Northwest: A Blank Slate

• IFTNC established ~ 30 yrs after forest soil

research began in earnest within the US

Early Objectives of IFTNC

• Define species nutrient limitations

• Define soil-site nutrient status

• Define site type effects on forest health and

productivity

• Develop diagnostic tools

for rapid site assessment

Nutrient Research: The First Decades

• Began with field

fertilization trials in the 80s

• Soils collected to identify native fertility

• Foliage analyzed for critical levels

• Fertilizer effect on

soil/foliage/growth

measured

Site Nutrient Limitations by Species

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60

Relative Cumulative Frequency

Nitrogen Concentration (%) Ponderosa Pine Grand Fir

Douglas-fir Lodgepole Pine

Critical Levels GF = 1.15 DF = 1.40 LPP = 1.20 PP = 1.10 Similar deficiencies for S, lesser for B

Soil Nutrient Richness by Rock Type

0 50 100 150 200 250 300 350

0.5 1 1.5 2 2.5 3 3.5

Annual Growth (ft3 ac-1 yr-1 )

Warm, Dry Cool, Moist Mixed

Metased Granite Basalt

Site Type & Forest Growth

IFTNC Forest Health Experiment

Site Type – Species Response to N

The Beginning of a Diagnostic Disconnect

• Foliar nutrient concentrations usually respond to nutrient amendments

• Foliar nutrition shows weak, but positive correlation with growth response

y = 0.2929x - 14.147 R² = 0.419

-20 -10 0 10 20 30 40

0 20 40 60 80 100 120 140

Foliar Sulfate-Sulfur (ppm)

Relative Growth Response

0.0 0.2 0.4 0.6 0.8 1.0

0.0 0.5 1.0 1.5 2.0 2.5

Relative Cumulative Frequency

GF Foliar N Concentration (%) Control

200-300 N

GF Growth – Foliar N Response to 200 N DF Growth – Foliar S

Content w/200 N

The Great Disconnect

• Standard soil chemical tests show:

– Very weak correlation with foliar response

– No correlation with growth response

Why the Soil Diagnostic Disconnect?

• Mechanistic

– Sampling intensity too low

– Not enough resources, both time and monetary, to capture soil variability

• Environmental

– Yr from harvest,

physiographic conditions will create unique soil environments not

comparable across site types (or even within)

Required Sample Size @ 10% Error w/10% C.I.

Soil Nutrient Mature Forest Clearcut Clearcut w/Fert

Mineralizable N 11 50 10

NO₃ 3 1 3

NH₄ 156 21 60

Available P 30 36 11

Available K 4 11 67

SO₄ 40 59 141

Available Boron 35 18 46

Ca 120 116 1

Mg 18 81 1

K 3 13 53

Na 13 13 1

Mn 88 28 67

Zn 62 4 17

Cu 3 86 77

Fe 2 81 7

Organic Matter 9 14 16

pH 1 1 1

Source: Rye on Ham Nutrient Mitigation Study

Is there a better way?

• Nutrient Pool or Nutrient Flux?

Water Extracted Nutrients

Chemically Extracted Nutrients

Not Ready to Abandon Soil Diagnostics

• Turned focus to Ion Exchange Resins

• Captures nutrients moving through soil solution

• An index of nutrient

bioavailability

The Beginning of IER Research

• Hybrid Approach

– Traditional soil pits

– Installed resin capsules to rooting depth or 100 cm

– Backfilled pit and returned 1 yr later

– Exhumed IERs and

collected soil samples for correlation

Early Results

Nutrient Flux Assessment

• Objective

– Detect treatment application

– Define sampling depth

Early Results

IER – Soil - Foliar Relationships

To Punt or Not to Punt?

• Remember our Hybrid Approach?

Required Sample Size @ 10% Error w/10% C.I.

IER Nutrient Mature Whole Tree Bole Only

NO₃ 2 308 429

NH₄ 6 15 4

P 108 57 50

K 104 199 176

SO₄ 34 182 3

B 132 93 131

Ca 115 87 7

Mg 148 99 89

Na 12 125 50

Mn 119 99 116

Zn 73 56 95

Cu 149 87 90

Fe 42 94 89

Complete Random vs.

Stratified Random

Stratified Sampling Approach

• Last Approach:

– Increased sample size – Placed IERs in soil

locations reflecting mean treatment effect

– Limited to surface horizon

– Reduced cost by installing many IERs within

treatment, but

composited for analysis

Preliminary FFP – IER Results

0 100 200 300 400 500 600 700 800

No Slash No Slash Whole

Tree Whole

Tree Bole Only Bole Only wo/Herb w/Herb wo/Herb w/Herb wo/Herb w/Herb Cumulative Soil NO3 Flux (ug cm-2) CANUS_{Year 3}

Year 2 Year 1

0 100 200 300 400 500 600 700 800

No Slash No Slash Whole

Tree Whole

Tree Bole Only Bole Only wo/Herb w/Herb wo/Herb w/Herb wo/Herb w/Herb Cumulative Soil NO3Flux (ug cm-2) RUBY_{Year 2}

Year 1

Annual Reassessment

• Build 5 yr seedling

growth dataset on FFP sites

• Correlate IER

cumulative nutrient flux with growth response

• Assess strength of IER to diagnose treatment

affect

The Future of Nutrient Diagnostics

• Foliar diagnostics will always be a tool in our silviculture kit

• Soil chemical diagnostics uncertain

• Perhaps shift focus to soil organic matter/carbon

• May need to rely on

parent material as a proxy

for soil chemistry