Carbon-sequestration capacity of typical chornozem in agrocenoses

Abstract

Goal. To assess the soil sequestration capabilities of typical chornozem under long-term (45 years) use of low-carbon soil-protective methods of cultivation and organo-mineral fertilizer systems compared to plowing in the agrocenoses of the central part of the Forest-Steppe of Ukraine. Methods. Field — to determine changes in the quantitative and qualitative state of humus in crop rotations under different fertilizer and cultivation systems, laboratory-analytical — to determine the content of total and labile organic matter, mathematical-statistical — to assess the reliability of the data obtained. Results. The influence of the type of crop rotation on the growth of humus content depends on the fertilizer system and the method of cultivation: in the 0–20 cm soil layer without fertilizer application, the humus increase in crop rotation A relative to crop rotation B was +0.17%, while in the case of no-shelf and surface cultivation methods, the increase was smaller 1.7 and 2.1 times. In the case of fertilizing, the addition of humus for plowing and tillage was +0.14–0.15%, and for surface cultivation, it was 1.33–1.42 times higher. In the researched crop rotations A and B in the 0–20 cm soil layer, the formation of C–CO2 LOR under shelfless and surface cultivation was significantly higher compared to plowing, and therefore in the 0–20 cm soil layer without fertilizer application, the effect of the crop rotation factor on the stock of C–CO2 SOC was higher. In the case of applying fertilizers under no-tillage, the effectiveness of the crop rotation factor on the stock of SOC decreased, and under surface tillage, it increased compared to plowing and tillage. Conclusions. Typical chornozems of the central part of the Forest-Steppe of Ukraine have a high sequestration capacity in agrocenoses of short crop rotations, which increases by 15–20% with the systematic use of low-carbon cultivation technologies: shelfless and surface cultivation methods compared to plowing. Under the organo-mineral fertilizer system, the sequestration capacity of chornozem in the 0–20 cm soil layer increases under plowless tillage and tends to decrease under surface tillage compared to plowing. The interaction of the factors of humus stock and C–CO2 SOC in crop rotation A was 3.12 times more effective compared to crop rotation B, which testifies to the determining importance of the type of crop rotation in the formation of the sequestration capacity of chornozem. The fertilizer system determines the rate of growth of sequestration, and the method of cultivation determines the nature of the manifestation of carbon monoxide accumulation in the chornozem of the agrocenosis.