Validation of the CANDY model with Russian long-term experiments

Abstract

The CANDY model has been qualitatively as- sessed for simulating long-term dynamics of soil organic carbon and tested against different long-term experiments representing various land uses and geographical sites, but never before against conditions of the Former Soviet Union (FSU). Our goal was to simulate long-term trends in soil organic carbon for the long-term experiments of Barybino (Moscow region, Russia), Grakov (Kharkow region, Uk- raine) and Yachenka (Minsk region, Belarus) representing the predominant arable soil types, climate conditions and typical management strategies for the investigated arable areas. The fit of modelled results to the observed data was evaluated to assess the suitability of the model for further applications in the FSU. The crop parameters of the CANDY model had to be adapted to the low yields ob- served under the Russian site conditions resulting in a higher sensitivity to crop-derived carbon input as a func- tion of yield. The results show that the approach of treating the organic carbon situated in micro pores as inert, is an applicable solution for simulating soil carbon dynamics under Russian conditions. This evaluation of CANDY, against long-term experiments from Russia, gives confi- dence for its wider application in this region.