Carbon balance in case of short-term green manure of a fallow in the conditions of the Baikal forest-steppe

Abstract

Abstract Changes in carbon balance during short-term green manure of a fallow in the conditions of the forest-steppe zone of the Baikal region are studied on the basis of the results of three-year field experiments. It was revealed that the introduction of green mass of oilseed radish (Raphanus sativus var. Oleifera Metzg) into gray forest soil at the end of the summer period significantly activates the processes of mineralization. The total CO2 emission from the soil surface in the variants with green manure increases by 1.3–1.6 times as compared with pure fallow. Compensation of gaseous carbon losses due to newly introduced organic matter is possible only at high yields of oilseed radish (3-5 tons of dry matter per ha) and hydrothermal conditions unfavourable for its mineralization. Under favourable conditions for the mineralization of fresh organic matter, a negative carbon balance is formed, but its value remains less deficient than in the variants of pure fallow. The data obtained allow us to recommend this technique of agriculture to reduce the share of net sources of carbon dioxide in the carbon balance.