Simulation Modeling of the Efficiency of Application of Various Organic Fertilizers on Plowed Chernozems under Changing Climate Conditions

A comparative simulation modeling of the prospects for using alternative fertilizer sources and minimal tillage as additional approaches to accumulate soil carbon under modern changing climate conditions has been performed on the basis of two long-term terrain experiments on chernozems. The dynamics of the organic cycle is analyzed, using the Rothamsted carbon model for four variants of organic–mineral fertilizer systems on leached chernozem (Luvix Chernozem) in Voronezh oblast and on ordinary chernozem (Haplic Chernozem) in Rostov oblast. Comparison of the effect of manure with green-manure fallow, application of composts and peat mixtures, and biochar and hydrochar in equivalent C rates has shown that application of alternative sources of organic origin enables additional accumulation of 8–10 t ha–1 of C by 2090, when applying composts and peat mixtures, 4–6 t ha–1 in case of biochar and hydrochar application, and 1–1.5 t ha–1, when using green-manure fallow as compared to manure application. The effect will gradually becomes sustainable, starting from the middle of the century. The introduction of biochar and composts with peat mixtures also stabilizes the accumulated C reserves in the second half of the century. A rate of increase in C reserves in the plowed layer of leached chernozem of 4‰ and C reserves of 87–89 t ha–1 can be achieved in 2020–2060 in case of minimal cultivation, doubling of the rates of organic fertilizers, and the use of composts. In ordinary chernozem with higher initial C reserves, their rise is stabilized at 86–91 t ha–1 by 2050, and an increase rate of 4‰ cannot be achieved.