Carbon balance assessment by eddy covariance method for agroecosystems with potato plants and oats & vetch mixture on sod-podzolic soils of Russia

The carbon balance for the agroecosystems with potato plants and oats & vetch mixture on sod-podzolics soils was evaluated using the eddy covariance approach. Absorption of carbon was recorded only during the growing season; maximum values were detected for all crops in July. The number of days during the vegetation period, when the carbon stocked in the fields with potatoes and oats & vetch mixture was about the same and accounted for 53-55 days. During this period, the increase in gross primary production (GPP) is well correlated with the crop yields. The curve of the gross primary productivity is closely linked to the phases of development of plants; for potatoes, this graph differs significantly for all phases. Form of oats & vetch mixture biomass curve shown linear increases. Carbon losses were observed for all the studied agroecosystems: for fields with an oats & vetch mixture they were 254 g C m^-2 y^-1, while for fields with potato plants they were 307 g C m^-2 y^-1. Values about 250-300 g C m^-2 per year may be considered as estimated values for the total carbon uptake for agroecosystems with potato plants and oats & vetch mixture on sod-podzolic soils.