UAB_015_07 VALIDATION OF CHANGES IN SOIL CARBON STOCKS IN SCOTLAND AND USE OF DATA TO DEVELOP THE ECOSSE MODEL MISteve Chapman John Bell Gordon Hudson Allan Lilly Willie Towers David Miller AUJo Smith Pete Smith

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

UAB_015_07 Scotland 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 CO 2 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 values More 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