RETROSPECTIVE LONG-TERM CARBON BALANCE UNDER CEREAL CROPS OF THE RUSSIAN FEDERATION

The retrospective carbon balance (CB) in soils under cereal crops of the Russian Federation for the period 1960–2023 is analyzed. The CB estimate was established by comparing the data of new carbon entering the soil (plant residues and crop byproducts) and heterotrophic soil respiration (R_H). The R_H was determined based on the nitrogen mineralizing capacity of soils over a year-round period of time. It is shown that in agriculture in Russia, for a long time, a negative carbon balance was formed under cereals crops. If from 1960 to 1980 there was a decrease in the C_org deficiency in the soil from –0.4 to –0.16 t/ha/year, from the beginning of the nineties to the present the deficit has been maintained at –0.4…–0.6 t/ha/year. Over a 60-year period, Russian agriculture has shown a close positive relationship between the total biological productivity of cereals (NPP) and heterotrophic soil respiration (R_H). It is shown that if all (and not just NPP) by-products of cereal crops had been used as fertilizers in the previous decades, the loss of soil organic carbon would have been practically reduced to zero.

balance of organic carbon in soils, crops, pure primary production of photosynthesis, heterotrophic respiration of soil, nitrogen mineralizing ability of soil, carbon neutrality