Kęstutis Romaneckas

Experimental analysis of CO2 emissions from agricultural soils subjected to five different tillage systems in Lithuania

Intensive agricultural production strongly influences the global processes that determine climate change. Thus, tillage can play a very important role in climate change. The intensity of soil carbon dioxide (CO₂) emissions, which contribute to the greenhouse effect, can vary depending on the following factors: the tillage system used, meteorological conditions (which vary in different regions of the world), soil properties, plant residue characteristics and other factors. The main purpose of this research was to analyse and assess the effects of autumn tillage systems with different intensities on CO₂ emissions from soils during different seasons and under the climatic conditions of Central Lithuania. The research was conducted at the Experimental Station of Aleksandras Stulginskis University from 2009 to 2012; and in 2014. The soils at the experimental site were classified as Eutric Endogleyic Planosol (Drainic). The investigations were conducted using five tillage systems with different intensities, typical of the Baltic Region. Deep conventional ploughing was performed at a depth of 230-250 mm, shallow ploughing was conducted at a depth of 120-150 mm, deep loosening was conducted at depths of 250-270 mm, and shallow loosening was conducted at depths of 120-150 mm. The fifth system was a no-tillage system. Overall, autumn tillage resulted in greater CO₂ emissions from the soil over both short- and long-term periods under the climatic conditions of Central Lithuania, regardless of the tillage system applied. The highest soil CO₂ emissions were observed for the conventional deep ploughing tillage system, and the lowest emissions were observed for the no-tillage system. The meteorological conditions greatly influenced the CO₂ emissions from the soil during the spring. Soil CO₂ emissions were enhanced as precipitation and the air and soil temperatures increased. Long-term investigations regarding the dynamics of CO₂ emissions from soils during the maize vegetation period indicated that autumn tillage systems affect the total soil CO₂ emissions. The highest (2.17 μmol m(-2)s(-1)) soil CO₂ emissions during the vegetation period were observed in the deep ploughing tillage system, and the lowest values were observed (1.59 μmol m(-2)s(-1)) in the no-tillage system.

The main physical properties of planosol in maize (Zea mays L.) cultivation under different long-term reduced tillage practices in the Baltic region

Abstract The impact of sustainable reduced tillage (RT) on the physical properties of soil is well documented worldwide; however, there is no precise information about the influence of long-term RT or no-till (NT) on the soils at the boundary for grain maize-growing in the semi-humid subarctic climate conditions of the Baltic states, especially on the formation of a hard-ened upper soil layer (10–15 cm in depth) — “loosening hardpan”. This study was carried out at the Research Station of Aleksandras Stulginskis University, Lithuania from 2009–2012. The investigations were based on a long-term (since 1988) field experiment. The aim of the investigation was to ascertain the influence of reduced primary tillage on the main soils physical properties. This study examined soils that were deep ploughing (DP), shallow ploughing (SP), deep cultivation (DC), shallow cultivation (SC), and no-till (NT). Reducing the tillage intensity to NT had no significant effect on the structural soils composition; however, the stability of the structure of the >1 and >0.25 mm-size fractions was significantly higher in the non-reversibly tilled (DC, SC) and NT plots. The penetration resistance of the DP soils was less after primary tillage and wintering, and became similar to the NT plots at the end of the maize growth season. After primary tillage and wintering, the soil moisture content in the upper soil layer (0–5 cm depth) of the NT plots was 17–49 and 16–18% higher than that in the DP. Long-term reduction of primary tillage up to NT generally had no significant effect on the moisture content and soil bulk density of the 0–10 and 10–20 cm layers. The results showed that long-term RT stabilized the physical quality of soil. Less soil penetration resistance was established in the DP plots compared to both RT and NT, however, indicators of the formation of a uniform “loosening hardpan” layer were not found. It is summarized that long-term RT or NT systems stabilize, or may increase, the physical quality of soil in crop cultivation with low inter-row coverage potential (maize), and could be applied in semi-humid subarctic climate conditions as a good option to prevent soil degradation.

Impact of living mulches on the physical properties of Planosol in monocropped maize cultivation

Abstract The complex mutual interactions between soil properties and plants in high-biodiversity mono-cropping agro ecosystems have not been widely investigated. For this purpose, during 2009-2011, a stationary field experiment was conducted at the Experimental Station of the Aleksandras Stulginskis University to establish the effect of a multi-component agrocenose (maize, living mulch, weeds) on the physical properties of the soil. Spring oilseed rape, white mustard, spring barley, Italian ryegrass, black medic, Persian clover and red clover were sown as living mulch into maize inter-rows. The stability of >1.0 mm aggregates increased between the beginning and end of the maize vegetative period in almost all of the crops containing living mulch. The greatest competition for moisture content between the inter-crops and maize was observed at the beginning of the vegetative period because of living mulches of long growing seasons using the most moisture. In many cases, the shear strength of the soil was significantly reduced by the living mulch in the middle of summer, when it covered the maize inter-rows. These findings show that the monocropping of maize with living mulch stabilises or improves the physical characteristics of the soil, highlighting its potential for sustainable maize growing.