Virginijus Feiza

The goal of this work was to determine the effect of soil freeze–thaw processes on the formation of water-stable aggregates (WSA) and plant available water (PAW) in soils of different textures, depending on the intensity of tillage: conventional tillage (CT), reduced tillage (RT) and no-tillage (NT). The WSA value (0.4%) and PAW mean (5.5%) in sandy loam were higher than in loam. The average content of WSA and PAW tended to decrease in the following order: air-dry soil > soil with water content at field capacity > soil near full saturation. These results indicate that WSA in soils that are close to full saturation upon freezing will be less stable after thawing and will decrease the PAW. The content of WSA in NT was 9.4% higher than in RT and 14% higher than in CT. The content of PAW in NT was 5.6% higher than in CT and 13.6% higher than in RT. The effects of various physical and chemical properties on PAW as a function of water level during the freeze–thaw process indicate that WSA content acted as a direct factor for PAW. In a temperate climate zone under dry meteorological conditions, NT would have a promising future for soil stability by maintaining higher WSA and PAW.

Investigations of CO₂ emissions in the context of different tillage systems are relevant not only for studying the effects of climate change but also for evaluating the sustainability of soil management. To better understand the influence of soil physico-chemical properties on CO₂ emissions, an experiment was conducted to measure the direct and indirect effects of these soil properties on CO₂ efflux. Soil CO₂ efflux is measured using a closed chamber method (LI-COR LI-8100A) under various tillage in two soil textures. Our research revealed that soil temperature, water content, soil organic carbon, total nitrogen, available phosphorus and pH significantly affected the soil–atmosphere CO₂ exchange rate. Soil CO₂, volumetric water content and soil temperature were higher in loam soil than in sandy loam soil. Soil CO₂ efflux was 8.6% lower in conventional tillage than under reduced and no tillage. Total nitrogen and soil organic carbon contents are dependent on tillage and decreased from no tillage to conventional tillage. Soil agrochemical properties such as SOC, total nitrogen, available phosphorus, available potassium and soil pH were higher evaluated in loam soil than in sandy loam soil. The results of this research are valuable contributions to knowledge on soil management in relation to CO₂ emissions on morainic loamy soil.

Conservation soil management strategies, particularly no-tillage and cropping strategies, have become an effective and widely adopted practice that has a direct influence on root parameters and mitigation of greenhouse gasses. However, the effect of different tillage and cropping strategies on root growth in field conditions is rarely studied. The study aimed to quantify and characterise the relationship between root network development and CO₂ emission and how these parameters are affected by different cropping and tillage strategies. Five different crop rotations were tested, with or without the inclusion of catch crops (CC), by growing them in the soil where different tillage practices were applied. Selected cropping strategies differed among themselves in terms of the frequency of CC grown per rotation. The data revealed that in NT treatments, the CO₂ emission (both autotrophic and heterotrophic simultaneously) was 25% higher than in CT. The cropping strategies were identified as an important factor influencing CO₂ emissions. An increase in CO₂ emission varied between 30 and 35% depending on the share of legume and CC inclusion. The frequency of CC grown per rotation has had an effect on the rate of CO₂ emission. The cropping strategy when CC was grown every year showed the lowest amount of CO₂ (by 26%), while in other cropping strategies, when CC was grown once or twice per rotation, significantly higher CO₂ emissions were observed. Root growth and their development were significantly affected (p < 0.05) by soil depth and cropping strategies concerning root length and root volume changes. The inclusion of CC into the rotations led towards a decrease in root volume (by 21%). Root length (R² = 0.45; p < 0.05) and root volume (R² = 0.82; p < 0.05) had a significant impact on soil CO₂ emissions. The results collected from 2021 to 2023 experiments indicated that cropping strategies and CC management areas are important tools not only for the improvement of root parameters but also for understanding how they affect CO₂ emissions. The main message for stakeholders is that the cropping strategies diversification with the inclusion of CC every year in a winter oil-seed rape, spring wheat and pea crop rotation (R/W/P + CC) had demonstrated the possibilities to reduce CO₂ emission and improve the root network parameters as compared to the monoculture strategy.

Plants respond to their environment through adaptations; for example, earthworms that create heterogeneity can lead to local adaptation of roots. This research identifies a mechanism to explain plant responses to earthworms and how these mechanisms are related. Our results show that tillage intensity has a negative effect on earthworms and root volume. The mean root volume and earthworm biomass under conventional tillage were lower than in reduced tillage and no-tillage. The root volume and the root diameter in the field with residues were higher than in the field without residues, while the root length density and earthworm biomass in the field with residues were lower than in the field without residues. This study demonstrates that the mean of the root length density and biomass of the earthworms were higher in sandy loam than in loam. Therefore, sand content had a positive effect on root length density (R² = 0.72, p < 0.01) and earthworm biomass (R² = 0.74, p < 0.01). Earthworm biomass had a positive effect on root volume (R² = 0.54, p < 0.05) and length density (R² = 0.88, p < 0.01). This confirms our hypothesis on the effect of earthworms on root systems.

An assessment of soil characteristics pertaining to their suitability for agricultural use in general is necessary to reverse the declining trend of soil quality and to ensure sustainable agriculture. The aim of this study was to determine the soil resistance (SRI) and degradation indices (SDI) under different agrotechniques and to find out whether management-induced changes are large enough to reduce soil degradation. The study was based on the comparison of physicochemical data of 3 long-term experiments conducted in the western part of Lithuania. Changes in soil properties over the past 20 years (1999–2019) have been determined. The most commonly used measures in Lithuania, such as soil liming, manuring, residue maintenance, and tillage, were selected for the analysis. The analysis carried out showed that the soil, which was fertilized with manure, had a higher value of soil quality parameters compared to natural Retisol: organic matter (by 0.53 percentage points), total nitrogen (by 0.04 percentage points), and the available amounts of phosphorus (by 69 mg/kg) and potassium (by 6.6 mg/kg). The assessment of the relative annual change in SOC content revealed that long-term soil manuring has significant SOC sequestration capability. Among the soil management techniques examined, it appeared that the greatest relative annual change (0.47 g kg⁻¹yr⁻¹) in SOC content was noted in manured soil. The results indicate that the higher degradation, and resistance values were observed in acid soil (pH 4.2), where liming was applied, indicating greater sensitivity to degradation. Based on analyzed indices, the agricultural practices ranked as: manuring > residue management > reduced tillage > liming. The lowest SRI values were obtained for low level of nutrients (from −0.11 to 0.89), organic carbon (from −0.72 to −0.49), and pH (from −0.25 to –0.1), indicating that these properties are more sensitive to applied agricultural practices compared to others. All these findings provide information for promoting better soil management, soil protection, land use planning, and the planning of remedial measures, especially in the most afflicted areas.

The intensity of carbon dioxide can vary depending on land management practices, temperature of the soil, and soil moisture. The soil CO₂ efflux per non-growing season was 61% lower than per growing season. The CO₂ efflux, averaged across data, tended to decrease in the following orders: grassland > forest > no-tillage > reduced tillage > conventional tillage (per non-growing season and measurement period) and grassland > forest > no-tillage > conventional tillage > reduced tillage (per growing season). Soil temperature averaged; in the natural land uses, it was 18% lower than in the anthropogenic land uses. Soil temperature averaged; in the non-growing season, it was 55% lower than under the growing season. The temperature (up to 25 °C) increased the soil CO₂ efflux per measurement period. By increasing the temperature in the soil, the soil efflux decreased in natural land use under growing season, but in anthropogenic land use, it increased per measurement period. The volumetric water content averaged; in the non-growing season, it was 3% lower than under the growing season. The volumetric water content had a positive effect on CO₂ efflux, but when the water content was higher than 15% in anthropogenic land use, and 20% in natural land use per growing season, the relationships were negative.

In order to control the amount of greenhouse gas emissions from agriculture, it is necessary to select the appropriate crop rotation and tillage intensity depending on the soil type and climatic conditions. However, their implementation in agricultural management methods has been insufficient until now. The main objective of this study was to investigate the changes and dependences in soil net CO₂ exchange rate (NCER) and main physico-chemical parameters under different tillage (conventional (CT) and no tillage (NT)) and crop rotation systems. Cropping systems significantly affected the amount of nutrients, but did not affect pH and organic carbon; otherwise, tillage vs. cropping systems had no significant effects on the soil chemical parameters analyzed. The data revealed that in NT treatments, the NCER was 28% higher than in CT. Different crop rotations also revealed a significant effect on NCER from the soil. Carbon dioxide fluxes increased in cropping systems where a higher share of catch crops were included. In NT systems, a comparatively higher soil moisture content was registered. In addition, the rotations with catch crops produced a higher (by 1–3%) soil moisture content. The temperature of the soil surface was not significantly affected by tillage or cropping systems; nevertheless, a trend towards higher soil surface temperatures in CT was determined, which might be affected by enhanced air circulation in the pores. Soil NCER increase correlated negatively with higher soil surface moisture content, while its relationship was positive with soil surface temperature increase. In general, soil surface temperature and moisture were the most significant factors in explaining the fluctuation in NCER from Cambisols in Lithuania under moderate climatic conditions.

Straw, as organic material, contains macronutrients and a wide range of micronutrients. Properly treated straw can become a valuable source for soil improvement and crop nutrition needs. The field experiment was carried out at the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry, in 2014–2021 on Cambisol. On a shallow ploughless tillage background, eight treatments were investigated: chopped straw + ammonium nitrate (CSA), chopped straw + ammonium nitrate + NPK (CSA+F), chopped straw + microorganisms (CSM), chopped straw + microorganisms + NPK (CSM+F), straw removed, not fertilized (SR), straw removed, fertilized (SR+F), chopped straw, not fertilized (CS), chopped straw, fertilized (CS+F). We hypothesized that treatment of straw with microbiological products in combination with mineral NPK fertilizers is a more efficient technology than treatment/non-treatment of straw with ammonium nitrate, either with or without NPK fertilizers. The aim of this work was to investigate the aftereffects of seven years use of mineral NPK fertilizers and bioproducts containing soil bacteria and microscopic fungi (Bacillus megaterium, Acinetobacter calcoaceticus, and Trichoderma reesei) in combination with straw management on soil sustainability (soil C sources, soil water release characteristics, pore-size distribution, aggregate stability, crop yielding capability) and soil vitality (CO₂ exchange rate-NCER). It was revealed that NCER was highest in the treatment CSM+F (Bacillus megaterium, Acinetobacter calcoaceticus, and Trichoderma reesei + NPK). It was 32.95% higher than in CSA (chopped straw without fertilizers) and 45.34% higher than in CSA+F (chopped straw + ammonium nitrate + NPK). Bioproducts applied favored soil vitality in general by exhibiting higher soil microbiological activity. As a result, a healthy and more viable Cambisol produced a higher winter wheat grain yield.

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.

Agricultural waste can have a catastrophic impact on climate change, as it contributes significantly to greenhouse gas (GHG) emissions if not managed sustainably. Swine-digestate-manure-derived biochar may be one sustainable way to manage waste and tackle GHG emissions in temperate climatic conditions. The purpose of this study was to ascertain how such biochar could be used to reduce soil GHG emissions. Spring barley (Hordeum vulgare L.) and pea crops in 2020 and 2021, respectively, were treated with 25 t ha⁻¹ of swine-digestate-manure-derived biochar (B₁) and 120 kg ha⁻¹ (N₁) and 160 kg ha⁻¹ (N₂) of synthetic nitrogen fertilizer (ammonium nitrate). Biochar with or without nitrogen fertilizer substantially lowered GHG emissions compared to the control treatment (without any treatment) or treatments without biochar application. Carbon dioxide (CO₂), nitrous oxide (N₂O), and methane (CH₄) emissions were directly measured using static chamber technology. Cumulative emissions and global warming potential (GWP) followed the same trend and were significantly lowered in biochar-treated soils. The influences of soil and environmental parameters on GHG emissions were, therefore, investigated. A positive correlation was found between both moisture and temperature and GHG emissions. Thus, biochar made from swine digestate manure may be an effective organic amendment to reduce GHG emissions and address climate change challenges.