UAB_015_07

VALIDATION OF CHANGES IN SOIL CARBON STOCKS IN SCOTLAND AND USE OF DATA TO DEVELOP THE ECOSSE MODEL

MI Steve ChapmanJohn BellGordon HudsonAllan LillyWillie TowersDavid Miller

AU Jo SmithPete Smith

UAB_015_07

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UAB_015_07

• ECOSSE differs from previous models (eg. ROTHC, SUNDIAL) in that

– It will simulate highly organic soils (important in Scotland)

– It has been developed to function at large scale (needed for national simulations)

UAB_015_07

Evaluation of ECOSSE• ECOSSE has been evaluated at

individual sites and performs well

• Evaluation at national scale was not initially possible (no data)

• Therefore, model was initially evaluated against CEH inventory. – Good agreement, but differences in specific

patterns

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0

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arab

le

gras

slan

d

fore

stry

sem

i-nat

arab

le

gras

slan

d

fore

stry

sem

i-nat

arab

le

gras

slan

d

fore

stry

sem

i-nat

arab

le

gras

slan

d

fore

stry

sem

i-nat

Cha

nge

in s

oil C

(kt

C (

20km

)-2 (

10yr

s)-1

ECOSSE CEH

to arable to grassland to forestry to semi-natural

R2 = 0.9666

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CEH estimates of change in soil C (kt C (20km)-2 (10yrs)-1

EC

OS

SE

sim

ulat

ion

of c

hang

e in

soi

l C

(kt C

(20

km)-2 (

10yr

s)-1

1:1 Line

UAB_015_07

Scotland 2000-2009

National simulations compare well with the CEH inventory…

• In this project we test ECOSSE against a new dataset

• Dataset = NSIS1 (sampled 30 years ago) plus NSIS2 (sampled 2007).

• Test simulation of C content across a wide range of soil types and conditions

• Test simulation of changes in C content.

Steps• Develop version of ECOSSE which

functions at site level using only the data required at national level

• Test against NSIS data• Improve model• Rerun national simulations

Link to UoL project

Rerun of national simulations

ASCII files of CO2 emissions to be used by UoL for comparison

Progress - NSIS evaluations

• Delay of 2 months in analysis of samples

• Simulations of NSIS now complete• Evaluations / improvements underway.

Good simulations of NSIS1 valuesMore spread in NSIS2 - indicates errors in simulation of trends in some cases

Simulations work well for all land use types

Simulations work well for land use change

Grassland to arable

But in some cases there are problems

Grassland to arable

Progress – National simulation

Scottish files prepared• When NSIS simulations are satisfactory

runs will be done