Application Of The Denitrification-Decomposition (DNDC) Model To Retrospective Analysis Of The Carbon Cycle Components In Agrolandscapes Of The Central Forest Zone Of European Russia

摘要

The retrospective dynamics of major components of the carbon cycle underland use changes in the Central Forest zone of European Russia was investigated. This areais known as one of the most important agricultural and economical regions of the country.We applied the process-based simulation model DNDC (DeNitrification-DeComposition)recommended by UNCCC and world widely used. In this study the DNDC model wasparameterized for Russian arable soils using official statistical information and data takenfrom published sources. Three main carbon variables in agrolandscapes were modelled:soil organic carbon, soil respiration, and net ecosystem exchange over the period of 1990-2017. For the analysis six administrative regions were selected: three with unchanged(permanent) arable land structure (Kaluga, Moscow, and Yaroslavl), and other threewith changed crop rotation (Kostroma, Smolensk, and Tver). All regions in the study arecharacterized by homogeneous soil cover and similar cultivated crops. The results of themodelling were verified using the data from field CO2 fluxes observations in the Europeanpart of Russia. In growing season, the agrolandscapes function as a net carbon sink andaccumulate C from the atmosphere into plant biomass. The dynamics of organic carbonin soil under growing crops depends on organic fertilizers in cultivation technologies,and if they aren’t inputted, soil loses carbon. During the last 30 years the cumulative ratesof net ecosystem exchange and soil respiration had decreased mostly due to reductionof arable land area. CO2 emission and soil organic carbon losses are the most importantcontrols of land degradation. Based on the dynamic patterns of CO2 fluxes, the regionsof the Central Forest zone could be separated into two groups. The group with centrallocation characterized by intensive soil respiration and high rate of accumulation oforganic carbon in soil, whereas peripheral group characterized by losses of soil organiccarbon and low rates of soil respiration. According to the modelling, within the period ofobservations the inter-annual changes of carbon fluxes are mainly controlled by rising airtemperature and heat supply, variable precipitation, and increasing concentration of CO2in the atmosphere. Among human activity the most important are change of arable landarea and decreasing amount of fertilizers.