108(1) str 1

ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 108, No. 1 (2021), p. 3–10
DOI 10.13080/z-a.2021.108.001

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

Abstract

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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