Zita Kriaučiūnienė

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 effect of sowing time on pest spreading in spring oilseed rape crop

The field experiments were conducted at the Experimental Station of Aleksandras Stulginskis University in 2015–2017. The aim of the experiment was to evaluate the influence of sowing time on spreading of pests and diseases in spring oilseed rape crop. The first sowing occurred when soil reached physical maturity, the other sowing dates were every 5 days in 2015–2016 and every 7 days in 2017. In 2015, the sowing time did not have a significant effect on the distribution of Alternaria brassicae . Meteorological conditions strongly influenced the severity of the disease. The sowing date had a significant influence on the distribution of Verticillium dahliae : in the spring rape crop sown in May, the stems were damaged by 6.4%, less compared to the crop sown in April. In 2016–2017, the rape seedlings in the plots of the latest sowing were significantly more damaged compared with those of earlier sowing dates. In 2016, spreading of Verticillium longisporum significantly increased by 3.7 times in the crop of spring rape sown on 10 May compared to other sowing dates. In 2017, the spreading of Verticillium dahliae in spring rape crops was more influenced by a colder than usual vegetation period and an abundant rainfall than the sowing time. In 2015, the intensity of Phyllotreta spp. damage in the rape seedling period (BBCH 10-19) significantly increased by 2.7 times with the sowing date from 30 April to 20 May. The spreading of Meligethes aeneus was the least in the spring oilseed rape sown at the optimal time (30 April and 5 May). In 2016–2017, Phyllotreta spp. were more intensively spread in the crops sown in April, and rape seedlings were significantly more damaged. In 2016, Meligethes aeneus were most widely spread in the spring rape crop of the earliest sowing (4 October). A significant decrease in the number of pests was detected in the rape crops sown in May compared to that sown in April. In 2017, the highest number of Meligethes aeneus was evaluated in the rape crop sown on 2 June, significantly by 3.9 times more compared with that in the earlier sown crop and by 2.9 times in the crop sown one week later. It is believed that the other generation of Meligethes aeneus from winter rape crops went to the spring rape crops. In 2016, there was a very strong statistically significant correlation between the sum of positive temperatures for the 10-day period up to the sowing of rapeseed and the prevalence of Phyllotreta spp. in crops: r = 0.98, P ≤ 0.05, and the damage intensity of rape seedlings by Phyllotreta spp. of (BBCH 10-19): r = 0.92, P ≤ 0.05. The warmer the weather was before rape sowing, the more active Phyllotreta spp. were. In 2017, strong correlations were established between the number of Phyllotreta spp. and the intensity of crop damage by Phyllotreta spp. and the crop density 3 days after the emergence: r = –0.82, P ≤ 0.05; r = –0.89, P ≤ 0.01, and 7 days after the emergence of spring rape: r = –0.81, P ≤ 0.05; r = –0.88, P ≤ 0.01.

The influence of biopreparations on the reduction of energy consumption and CO 2 emissions in shallow and deep soil tillage

The application of innovation in agriculture technologies is very important for increasing the efficiency of agricultural production, ensuring the high productivity of plants, production quality, farm profitability, the positive balance of used energy, and the requirements of environmental protection. Therefore, it is a scientific problem that solid and soil surfaces covered with plant residue have a negative impact on the work, traction resistance, energy consumption, and environmental pollution of tillage machines. The objective of this work was to determine the dependence of the reduction of energy consumption and CO2 gas emissions on different biopreparations. Experimental research was carried out in a control (SC1) and seven different biopreparations using scenarios (SC2-SC8) using bacterial and non-bacterial biopreparations in different consistencies (with essential and mineral oils, extracts of various grasses and sea algae, phosphorus, potassium, humic and gibberellic acids, copper, zinc, manganese, iron, and calcium), estimating discing and plowing as the energy consumption parameters of shallow and deep soil tillage machines, respectively. CO2 emissions were determined by evaluating soil characteristics (such as hardness, total porosity and density). Meteorological conditions such average daily temperatures (2015-20.3 °C; 2016-16.90 °C) and precipitations (2015-6.9 mm; 2016-114.9 mm) during the month strongly influenced different results in 2015 and 2016. Substantial differences between the averages of energy consumption identified in approximately 62% of biological preparation combinations created usage scenarios. Experimental research established that crop field treatments with biological preparations at the beginning of vegetation could reduce the energy consumption of shallow tillage machines by up to approximately 23%, whereas the energy consumption of deep tillage could be reduced by up to approximately 19.2% compared with the control treatment. The experimental research results reveal the reduction of CO2 emissions in shallow tillage to approximately 20.14% (and that in deep tillage to approximately 19.16%) when works were performed by different biological preparation usage scenarios. This experimental research demonstrates the efficient use of the special adaptation of a new biotechnological method for the reduction of the energy consumption and CO2 gas emissions of agricultural machinery.

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.

Allelopathic effects of aqueous extracts of oilseed rape residues on spring barley germination and growth.

Tyrimai atlikti 2011 m. Aleksandro Stulginskio universiteto Bandymų stoties laboratorijoje. Tyrimų tikslas – nustatyti ir įvertinti žieminių ir vasarinių rapsų liekanų (kūlenų, ražienojų ir saknų) vandeninių istraukų alelopatine įtaką vasarinių miežių dygimui bei augimui. Eksperimento variantai: A veiksnys – rapsų liekanos: 1) žieminių rapsų kūlenos; 2) žieminių rapsų ražienojai; 3) žieminių rapsų saknys; 4) vasarinių rapsų kūlenos; 5) vasarinių rapsų ražienojai; 6) vasarinių rapsų saknys. B veiksnys – vandeninių istraukų koncentracijos: 1) distiliuotas vanduo; 2) 1 : 6250 (rapsų liekanų ir vandens santykis); 3) 1 : 1250; 4) 1 : 250; 5) 1 : 50; 6) 1 : 10. Žieminių kviecių ir vasarinių miežių grūdai daiginti ant filtrinio popieriaus, sudrėkinto paruostų koncentracijų vandeninėmis istraukomis, Petri lėkstelėse, klimatinėje kameroje. Visų koncentracijų rapsų liekanų vandeninės istraukos (1 : ≥10), palyginti su distiliuotu vandeniu, slopino vasarinių miežių (nuo 13,6 iki 28,6 % vnt.) dygimą. Miežių daigelių (nuo 14,4 iki 16,4 %) ir saknelių augimas (nuo 14,2 iki 19,2 %), palyginti su distiliuotu vandeniu, buvo stimuliuojamas veikiant visų rapsų liekanų stipresnių koncentracijų (1 : 250 ir 1 : 50) vandeninėmis istraukomis. Vertinant rapsų liekanų įtaką miežių dygimui nustatyta, kad vasarinių miežių dygimą stimuliavo žieminių rapsų ražienojai bei vasarinių rapsų saknys, o daigelių ir saknelių augimą – vasarinių rapsų kūlenos bei ražienojai. Žieminių rapsų kūlenų vandeninių istraukų optinis tankis nustatytas didžiausias, vasarinių rapsų saknų vandeninių istraukų – mažiausias. Visų rapsų liekanų 1 : 10 koncentracijos vandeninės istraukos optinis tankis nustatytas nuo 4,0 iki 12,4 karto didesnis, palyginti su kitų koncentracijų vandeninėmis istraukomis. Raktažodžiai: alelopatija, rapsai, vasariniai miežiai, liekanos, vandeninės istraukos, optinis tankis