ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 108, No. 1 (2021), p. 3–10
The effect of environmental factors and root system on CO2 efflux in different types of soil and land uses
Mykola KOCHIIERU, Virginijus FEIZA, Dalia FEIZIENĖ, Jonas VOLUNGEVIČIUS, Irena DEVEIKYTĖ, Vytautas SEIBUTIS, Simona PRANAITIENĖ
Carbon dioxide (CO2) efflux from 0–5 cm topsoil layer in conventional tillage plots, in grassland and forest Retisol (in West Lithuania in a hilly terrain) and Cambisol (in Central Lithuania in a plane terrain) was investigated using a closed chamber method. The soil CO2 efflux was measured six times per growing season from April to August in 2018. Soil temperature and the volumetric water content were recorded at 5 cm depth at the same time as soil CO2 efflux measurements. Small soil monoliths were collected for the measurements of plant root parameters within 0–10 cm layer and were investigated later in the laboratory.
In Cambisol, the efflux values ranged from 0.20 to 2.67 μmol CO2 m-2 s-1 under conventional tillage, from 1.10 to 3.41 μmol CO2 m-2 s–1 in grassland and from 0.89 to 2.28 μmol CO2 m-2 s-1 in forestland. In Retisol, the efflux values varied from 0.81 to 3.54 μmol CO2 m-2 s-1 under conventional tillage, from 1.23 to 2.69 μmol CO2 m-2 s-1 in grassland and from 0.88 to 2.06 μmol CO2 m-2 s-1 in forestland. The soil temperature varied from 11.5°C to 33.6°C during the experimental period and averaged 22.8°C and 21.1°C at 5 cm depth in Cambisol and Retisol, respectively. The volumetric water content at 5 cm depth averaged 18.7% and 23.9% in Cambisol and Retisol, respectively. The volumetric water content in Cambisol was markedly lower than in Retisol during the whole experimental period. The maximum root volume within 0–10 cm depth was determined in grassland Retisol. Root volume under conventional tillage in Cambisol was 6.2-fold lower, in Retisol – 5.1-fold lower, in forest Retisol – 1.9-fold lower, in forest Cambisol – 1.4-fold lower and in grassland Cambisol – 1.1-fold lower compared to grassland Retisol. Average CO2 efflux from Retisol was 12% lower than that from Cambisol. Soil CO2 emission decreased in the following order: Cambisol – grassland > forestland > conventional tillage plots and Retisol – grassland > conventional tillage plots > forestland. Volumetric water content was found to increase soil CO2 efflux; however, at the content higher than 20%, efflux decreased. A soil temperature of up to 25°C increased soil CO2 emission. However, with a further increase in soil temperature, soil respiration decreased in both soil types investigated.
The decrease in root volume and root length density depended on the land use: grassland > forestland > conventional tillage plots.
Keywords: Cambisol, Retisol, root volume, soil temperature, volumetric water content.
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