The most important component of agricultural system are soils as the basis for the growth of plants, accumulation of water, plant nutrients and organic matter. The main task of our research was to ascertain changes in soil organic carbon (SOC) and mobile humified carbon fractions in digestate-treated soils. We have performed three field experiments using the same design on two soil types in 2019–2020. We studied the fertilization effects of different phases of digestate on Retisol and Fluvisol. Fertilization treatments: control; separated liquid digestate 85 kg ha⁻¹ N; and 170 kg ha⁻¹ 170 N; separated solid digestate 85 kg ha⁻¹ N; and 170 kg ha⁻¹ N. We have found a greater positive effect on the increase in SOC because of the use of the maximum recommended fertilization rate of the solid digestate. The content of mobile humic substances (MHS) tended to increase in grassland and crop rotation field in digestate-treated soil. In our experiment, maximum concentration of SOC was found in 0–10 cm soil layer, while in the deeper layers the amount of SOC, MHS and mobile humic acids proportionally decreased. We concluded, that long-term factors as soil type and land use strongly affected the humification level expressed as HD (%) in the soil and the highest HD was determined in the grassland soil in Fluvisol.

The study aimed to quantify the relationship between root parameters and soil macropore characteristics in two soil layers of Retisol from a hilly landscape in Western Lithuania, as influenced by different land use systems. The decreases in root volume and root length density were dependent on...

The key process in understanding carbon dynamics under different ecosystems is quantifying soil CO₂ efflux. However, this process can change annually as it depends on environmental variables. The results of this paper present the effects of root network, soil temperature, and volumetric water content on soil CO₂ efflux, which were investigated on Retisol of two types of land uses in Western Lithuania in 2017–2019: forest and grassland. It was determined that the average soil CO₂ efflux in the grassland was 32% higher than in the forest land. The CO₂ efflux, average across land uses, tended to increase in the following order: 2017 < 2018 < 2019. Dry weather conditions with high temperatures during the vegetation period governed the soil CO₂ efflux increase by 14%. Soil temperature (up to 20 °C) and volumetric water content (up to 23–25%) had a positive effect on the soil CO₂ efflux increase on Retisol. We established that the root’s activity plays one of the main roles in the CO₂ production rate—in both land uses, the soil CO₂ efflux was influenced by the root length density and the root volume.

The aggregate stability of the soil is subject to the influence of anthropogenic factors and is of great interest all over the world. The research aimed to quantify the correlations between soil organic carbon, total nitrogen, total phosphorus, and total potassium, soil macropore parameters and...

Biogas and anaerobic digestion has begun to be considered an important renewable and sustainable energy source. The sustainable development of the anaerobic digestion process depends largely on the ability to manage large amounts of by-products generated during the biogas production process. We hypothesized that the use of digestate increases the accumulation of C in stable forms. We supposed that the effect of digestate on soil depends on the land-use system, leading to different stratifications of C. The main task of our research was to ascertain changes in the amount of stabile organic carbon (SOCstabile) in digestate-treated soils. Two field experiments were performed using the same design in 2019–2020. We studied the fertilization effects of digestate on Fluvisol. Fertilization: control; separated liquid digestate 85 kg ha⁻¹ N and 170 kg ha⁻¹ 170 N; separated solid digestate 85 kg ha⁻¹ N and 170 kg ha⁻¹ N. A randomized experimental design with three field replicates was used. In terms of carbon stabilization in Fluvisol, soil used for grassland showed an advantage over the arable soil. The study showed that digestate, especially solid digestate, contributes to C accumulation and stabilization in the soil.