The effect of soil macroporosity, temperature and water content on CO2 efflux in the soils of different genesis and land management

Abstract

This paper analyses the effects of soil macropores, temperature and water content on soil carbon dioxide (CO 2) efflux behaviour, which could help understand the mechanism of CO 2 efflux as influenced by soil type and land use methods. The temporal dynamic changes of CO 2 efflux from the soil surface using a closed chamber method (LI-COR LI-8100A Automated Soil CO 2 Flux System) were measured. Soil CO 2 efflux was investigated at a topsoil depth of 0-5 cm in (1) arable land under conventional tillage on Cambisol (CM), (2) grassland on Cambisol, (3) park on Cambisol, (4) arable land under conventional tillage on Retisol (RT), (5) grassland on Retisol and (6) forest on Retisol. CO 2 emission was measured six times per growing season from May to September in 2017. Soil macropore network was researched by implementing an X-ray computed tomography and carried out at the laboratory of the Institute of Agrophysics, Polish Academy of Sciences in Lublin, Poland. Macropores resulting from soil pedogenesis and land use methods played an important role on soil water, temperature and gas transport. The type of soil vegetation cover and amount of soil macropores significantly influenced soil respiration rate. The efflux values were recorded ranging from 0.71 to 3.43 μmol CO 2 m-2 s-1 (Cambisol) and from 0.70 to 3.05 μmol CO 2 m-2 s-1 (Retisol) in the grassland, from 0.43 to 2.57 μmol CO 2 m-2 s-1 (Cambisol) in the park, from 0.44 to 2.52 μmol CO 2 m-2 s-1 (Retisol) in the forest, from 0.52 to 2.68 μmol CO 2 m-2 s-1 (Retisol) and from 0.09 to1.57 μmol CO 2 m-2 s-1 (Cambisol) in the conventional tillage. Computational tomography data revealed that the content of macropores amounted to 10.75% in the grassland site, 1.97% in the park and 1.21% in the conventional tillage within the soil depth of 3-8 cm of the Cambisol and 6.45% in the forest, 4.94% in the conventional tillage and 3.86% in the grassland at the same soil depth of the Retisol. Soil temperature, water content and macroporosity were the main factors exerting the influence on soil gas origination rate. The relationship between soil CO 2 efflux and volumetric water content at a 5 cm depth can be described by a linear regression model y = 0.0943x − 0.7651, R 2 = 0.53 (valid for volumetric water content from 22.5 to 27.0 vol.% on Retisol and from 16.8 to 24.4 vol.% on Cambisol). Also, linear regression model y = 0.1167x − 0.8214, R 2 = 0.65 showed the relationship between soil CO 2 efflux and soil macroporosity at the 3-8 cm depth. Soil CO 2 efflux displayed a typical polynomial relationship with soil temperature at the 5 cm depth; however, the relationship was very weak. Both soil type and land use methods had a noticeable influence on macroporosity, surface area and macropore range of soil pore-size distribution. The amount of macropores in macropore geometry was an important factor when dealing with CO 2 flow. Topsoil CO 2 efflux under contrasting vegetation cover and management conditions on Cambisol and Retisol was directly related to soil macroporosity and volumetric...

Quantification of the relationship between root parameters and soil macropore parameters under different land use systems in Retisol

“…The soil surface area, the volume of the macropores, and macropore size were highly correlated (Table 4). These results are in line with the data published by Luo et al (2010) and Kochiieru et al (2018).…”

“…This method is more accurate and has a higher resolution than traditional methods, such as spectral analysis, dye tracking, and the image analysis of soil thin sections. In recent times, many studies related to the parameters of the structure of macropores (which include characterizations such as macroporosity, volume, distribution of macropore size, tortuosity and surface area) have been carried out using X-ray CT for various types of soil, and various systems of land use and management (Hu et al, 2015;Katuwal et al, 2015;Kochiieru et al, 2018;Larsbo et al, 2014).…”

The Combined Effect of Biochar and Mineral Fertilizer on Triticale Yield, Soil Properties under Different Tillage Systems

“…Both soil type and land usage have a significant influence on the overall macroporosity, its surface area, and the distribution of pores belonging to the macropore group. Accordingly, the number of macropores, as well as the number of mesopores and their distribution, is an important factor in determining the amount of water in those pores and their electrical conductivity [ 35 , 36 ].…”

Lignoceliuliozinės žematemperatūrės bioanglies hidrofiliškumo didinimo tyrimai ir technologijos kūrimas

“…Ir dirvožemio tipas, ir žemėnauda turi reikšmingą įtaką bendram makroporingumui, jo paviršiaus plotui ir porų pasiskirstymui dirvožemyje. Atitinkamai makroporų, taip pat ir mezoporų skaičius bei jų pasiskirstymas yra svarbus veiksnys, lemiantis vandens kiekį tose porose ir jų elektrinį laidį (Kochiieru et al, 2018(Kochiieru et al, , 2020.…”