Experimental analysis of CO₂ emissions from agricultural soils subjected to five different tillage systems in Lithuania

Intensive agricultural production strongly influences the global processes that determine climate change. Thus, tillage can play a very important role in climate change. The intensity of soil carbon dioxide (CO₂) emissions, which contribute to the greenhouse effect, can vary depending on the following factors: the tillage system used, meteorological conditions (which vary in different regions of the world), soil properties, plant residue characteristics and other factors. The main purpose of this research was to analyse and assess the effects of autumn tillage systems with different intensities on CO₂ emissions from soils during different seasons and under the climatic conditions of Central Lithuania. The research was conducted at the Experimental Station of Aleksandras Stulginskis University from 2009 to2012; and in 2014. The soils at the experimental site were classified as Eutric Endogleyic Planosol (Drainic). The investigations were conducted using five tillage systems with different intensities, typical of the Baltic Region. Deep conventional ploughing was performed at a depth of 230–250 mm, shallow ploughing was conducted at a depth of 120–150 mm, deep loosening was conducted at depths of 250–270 mm, and shallow loosening was conducted at depths of 120–150 mm. The fifth system was a no-tillage system. Overall, autumn tillage resulted in greater CO₂ emissions from the soil over both short- and long-term periods under the climatic conditions of Central Lithuania, regardless of the tillage system applied. The highest soil CO₂ emissions were observed for the conventional deep ploughing tillage system, and the lowest emissions were observed for the no-tillage system. The meteorological conditions greatly influenced the CO₂ emissions from the soil during the spring. Soil CO₂ emissions were enhanced as precipitation and the air and soil temperatures increased. Long-term investigations regarding the dynamics of CO₂ emissions from soils during the maize vegetation period indicated that autumn tillage systems affect the total soil CO₂ emissions. The highest (2.17 μmol m⁻² s⁻¹) soil CO₂ emissions during the vegetation period were observed in the deep ploughing tillage system, and the lowest values were observed (1.59 μmol m⁻² s⁻¹) in the no-tillage system. - Highlights: • The experimental research results of soil CO₂ emissions are presented. • Autumn tillage intensity influenced soil CO₂ emissions and soil temperature. • Soil CO₂ emission intensity depends on temperature and precipitation. • The highest soil CO₂ emissions occurred in the deep ploughing system. • Under vegetation, the lowest soil CO₂ emissions occurred in the no tillage system