Effects of Organic Retention and Management on Nitrogen Flux in a

Coarse Outwash Soil at Matlock, WA.

A.B. Adams and Rob HarrisonUniversity of Washington

in association with

Pacific Northwest Research Station (Tim Harrington) and

Green Diamond Resource Company (Randal Greggs)

INTRODUCTION

• ONE OF 3 SITES – ALL TREATED AS INDEPENDENT STUDIES

• 3 LEVELS OF WOODY DEBRIS MANIPULATION WITH OR WITHOUT COMPETING VEGETATION CONTROL

• 3 x 2 FACTORIAL• TREATMENTS APPLIED TO 0.3-ha

PLOTS (10 x 30 m)

A FENCE WAS BUILT AROUND THE STUDY AREA

WEATHER DATA IS COLLECTED ON-SITE BY THE USDA PNW FOREST SERVICE LAB

MANAGEMENT TREATMENTS

• SECOND GROWTH DOUG-FIR FOREST (F)

• STEM ONLY–NO VEGETATION CONTROL (BO-NVC)

• STEM ONLY–VEGETATION CONTROL (BO-VC)

• WHOLE-TREE–NO VEGETATION CONTROL (WT-NVC)

• WHOLE-TREE – VEGETATION CONTROL (WT-VC)

ADJACENT SECOND GROWTH FOREST WASLEFT STANDING AND SERVED AS A CONTROLUse arrow to show forest

BOLES ONLY WERE REMOVED ANDNO VEGETATION CONTROL WAS APPLIED

BOLES ONLY WERE REMOVED AND VEGETATION CONTROL WAS APPLIED

WHOLE TREES WERE REMOVED AND THERE WAS

NO VEGETATION CONTROL

WHOLE TREES WERE REMOVED (DISTANT PLOT) AND VEGETATION CONTROL WAS APPLIED

Will cut out minipiles to show only Whole Tree-Veg Control(upper picture

Will label horizons and cut to use left side of photo and soil properties

TWO LYSIMETERS (20 cm AND 100 cm) TENSION LYSIMETERS WERE INSTALLED AT EACH PLOT TO MEASURE NITROGEN

AND CARBON FLUXWill add lab graphic here that includes subterranean pictorial of

lysimeters

BASIS FOR LYSIMETER DEPTHS

• 20 cm is depth at which plants adsorb nutrients

• 100 cm is depth at which solutes are considered leached from system

NO3-N CONCENTRATIONS AT 20 cm

NO3-N CONCENTRATIONS AT 100 cm

EVAPOTRANSPIRATION MODEL IS USED TO CALCULATE FLUX

COMPARATIVE CONCENTRATIONS OFNH3, NO3 AND DON SHOWN ON ONE SLIDE.This is a priority

• IF TIME PERMITS DO DISSOLVED ORGANIC CARBON FLUX

• Not a priority

SUMMARY

1) STUDY ALLOWS FOR CALCULATION THE VARIOUS LEVELS OF NUTRIENTS AND THEIR STABILITY IN DIFFERENT ECOSYSTEM COMPARTMENTS

2) RESULTS WILL ALLOW MANAGERS TO CONSIDER THE EFFECT OF DIFFERENT LEVELS OF LOGGING ON NUTRIENT POOLS AND PRODUCTIVITY

3) RESULTS CAN BE COMPARED WITH FALL RIVER AND MOLALLA

Slides not used follow

A HOBO TEMPERATURE SENSOR WAS INSTALLEDAT EACH PLOT AT A HEIGHT OF 25 CM

A RAIN GUAGE IS COLLECTING DATA 24/7/52