The dynamics of water quality indices and the impact of Akademija pond on their changes in the Dotnuvėlė River, middle Lithuania

Lietuvoje kaip ir daugelyje pasaulio šalių dedama daug pastangų, kad vandenų tarša mažėtų. Pagal valstybinio monitoringo duomenis nustatyta, kad Lietuvos upėse vis dar išlieka didelės biogeninių medžiagų koncentracijos. Vandens tarša yra viena iš pagrindinių ES aplinkosaugos problemų. Norint išsiaiškinti pagrindines vandens taršos problemas, būtina atlikti nagrinėjamos upės vandens kokybės parametrų matavimus. Tam tikslui nuo 2010-11-06 iki 2013-05-07 buvo atliekami vandens kokybės tyrimai, kurių metu buvo fiksuojami šie parametrai: vandens lygis, ištirpusio deguonies koncentracijos, aktyvi vandens reakcija (pH), bendrosios mineralizacijos, elektrinio laidžio, nitratų ir vandens temperatūros kaita. Vandens kokybės parametrai matuoti aukščiau ir žemiau Akademijos tvenkinio, kuris susidarė 1968 m. ant Dotnuvėlės upės ties Akademijos gyvenviete. Pagal minėtus duomenis buvo nustatyta vandens kokybė atskiruose Dotnuvėlės ir jos intako Kačiupio upių taškuose. Atlikus tyrimą buvo nustatyta, kad Akademijos tvenkinys sąlygoja nitratų pasiskirstymą upėje, t. y. pastebėtas nedidelis nitratų padidėjimas upėje žemiau tvenkinio. Nustatyta, kad bendroji mineralizacija rudenį didėjo, žiemos metu svyravo, o pavasarį mažėjo. Pagal ištirpusio deguonies kiekį visose matavimo stotyse vanduo atitiko labai blogą, blogą, vidutinę, gerą arba labai gerą būklę. Vandens lygis Akademijos tvenkinyje tiriamuoju laikotarpiu svyravo 0−19 cm ribose stoties „O“ atskaitos atžvilgiu. Kitų išmatuotų vandens kokybės parametrų reikšmės Dotnuvėlės ir Kačiupio upėse buvo labai panašios. Pastebėta, kad visiems matuotiems vandens kokybės parametrams didelę įtaką darė sezoniškumas ir upės vandeningumas. Palyginus Dotnuvėlės ir Kačiupio upės vandens kokybės parametrus, nustatyta, kad visi vandens kokybės rodikliai rodė geresnė būklę Dotnuvėlės upėje. Manoma, kad tam turėjo įtakos gyvulininkystės fermos vykdoma veikla ir pasklidoji tarša Kačiupio upėje.  In Lithuania, as well as in other countries of the world, great efforts are made to reduce water pollution. According to the national monitoring data, there is still a high concentration of biogenic substance in Lithuanian rivers. Water pollution problem is one of the key EU environmental issues. In order to find out the main water pollution problems, it is necessary to conduct the measurements of water quality parameters of the investigated River. For this purpose, from 06/11/2010 to 07/05/2013 water quality measurements were carried out, during which values of the following parameters were recorded: water level fluctuations, dissolved oxygen concentration, pH, total dissolved solids, the variation of nitrates and water temperature. Water quality parameters were measured upstream and downstream the pond at Akademija settlement. In accordance with the given data, water quality was identified in several points of Dotnuvėlė and Kačiupio rivers. The research revealed that the pond of Akademija determines nitrate distribution in the river, i.e. a slight nitrate increase was observed in the river below the pond. It was disclosed that in autumn total dissolved solids increased, in winter the concentration varied and it decreased in spring. According to the amount of dissolved oxygen at all measurement stations, water corresponded to a poor, extremely poor, moderate, good or extremely good condition. During the research period, water level in the pond of Akademija ranged from 0-19 cm. Other values of measured water quality parameters in the Dotnuvėlė and Kačiupio rivers were very similar. It was noticed that all the measured water quality indices were significantly influenced by the seasonality and river runoff. Having compared water quality parameters of Dotnuvėlė and Kačiupo rivers, it was carried out that all water quality indicators showed better quality in Dotnuvėlė River. It is believed that lower quality in the Kačiupio River was affected by the activities of animal breeding and other nonpoint sources of pollution.Žemės ūkio akademijaVytauto Didžiojo universiteta

The Effects of Organic and Mineral Fertilisers on Maize N Status Under Water and Cold Stress Conditions in a Nemoral Climate

Kukurūzai (Zea mays L.) yra vieni iš trijų pagrindinių augalų pasaulyje, svarbiausių maisto, pašarų ir kuro šaltinių (Tenaillon ir Charcosset, 2011). Europos Sąjungoje kukurūzų grūdų derlius sudaro 20,8 % viso javų derliaus (FAOSTAT, 2016), be to, yra prognozuojama, kad iki 2026 m. kukurūzų pasėlių plotai ir toliau didės (~8 %). Tikėtina, jog kukurūzų plotai ateityje plėsis dėl didesnio nei kitų javų derlingumo potencialo, ypač pastaraisiais metais į Europos Sąjungą priimtose šalyse, kuriose derlingumo potencialo atotrūkis nuo faktinio derlingumo ūkininkų laukuose yra didžiausias (EU Commission, 2016). ha-1 (FAOSTAT, 2017). Pasaulyje kukurūzų grūdų produkcija esmingai pradėjo didėti nuo 1930 m., kai buvo sukurtos naujos hibridinės kukurūzų veislės ir pradėtos taikyti naujos auginimo technologijos (Tollenaar ir Lee, 2011).Maize (Zea mays L.), one of the three most cultivate crops in the world, is an important source of food, feed, fuel and fibre (Tenaillon and Charcosset 2011). In the European Union (EU-28), grain maize production accounts for 20.8% of the total cereal production (FAOSTAT 2016), and until 2026, a further expansion of the maize cultivation area of around 8% is expected.In the Nordic-Baltic countries, successful maize forage production is possible at a latitude of at least 58°N; however, currently, only a minor proportion of maize is harvested as grain in Denmark, Lithuania and Sweden (Swensson 2014). Despite the rapid maize expansion in northern Europe, the short growing seasons, the occurrence of late/early frosts, the rain quantity, which usually does not match with the highest water demand during the growing period, and the incidence of drought are considered to be the primary factors still limiting maize expansion in northern regions (Olesen et al. 2011).Žemės ūkio akademijaVytauto Didžiojo universiteta

Advancements in soil organic carbon mapping and interpolation techniques: A case study from Lithuania’s moraine plains /

Monitoring soil organic carbon (SOC) is essential for assessing the sustainability of soil usage. This study explores the spatial variability and mapping of SOC in Lithuania’s Nevėžis Plain using various interpolation methods, with an emphasis on understanding the impacts of soil typological units, moisture regimes, and erosion on SOC distribution. A total of 275 soil samples were collected from agricultural croplands at depths of 0–10 cm, supplemented by 38 samples from previous studies. The SOC map was created based on the contours of the Lithuanian soil geodatabase. Statistical analysis revealed that the distribution of SOC in the studied area was significantly influenced by soil moisture and the degree of erosion. Based on these findings, SOC mapping was conducted according to the contours of Lithuanian soils. Comparing the interpolation methods that were analyzed, it was found that the kriging, RBF, and EBK methods fail to adequately capture the minimum and maximum values of SOC, while the IDW fails to adequately capture only the minimum values. In summary, the integrated geographical approach is complex but applicable to SOC mapping. This method facilitates the creation of adaptable SOC maps that are both geographically and pedologically informed. Key principles to apply this approach for future research and practical application should include establishing a statistically reliable data foundation, categorizing samples based on contrasting soil moisture regime, degrees of erosion, and land use patterns, and developing contouring principles along with a criteria algorithm that enables accurate spatial interpolation of average SOC values

CERES‐Maize model performance under mineral and organic fertilization in nemoral climate conditions

Little information is available regarding the performance of the CERES-Maize model under nemoral climate conditions. Therefore, this study aims to estimate and compare major soil-plant N cycle parameters in grain maize (Zea mays L.) crop after application of synthetic and different organic fertilizers solely or in combination in nemoral zone maize production, using the Decision Support System for Agrotechnology Transfer (DSSAT) model. Field experiments carried out during 2015, 2016, and 2017 in Akademija (Lithuania) were considered for model calibration and validation. The model was successfully validated for total aboveground biomass (TAB, R2 = .89), grain yield (GY, R2 = .85), and acceptably for leaf area index (LAI, R2 = .57), total plant N uptake (R2 = .61), and residual soil mineral N (R2 = .64). The lower plant N uptake and soil mineral nitrogen (SMN) observed for the pelletized cattle manure (PCM) and green waste compost (GWC) treatments compared to the fertilization with synthetic ammonium nitrate (AN) were successfully captured by the model. Finally, the model provided reasonable predictions of the temporal dynamics of measured soil water content (SWC) and soil temperature. The validated model was further used to provide N loss estimations during the maize growing seasons via leaching and gaseous emissions. The results showed that the CERES-Maize model can successfully be used to simulate maize growth under the extreme climatic conditions of the nemoral zone in combination with different N managements. Nevertheless, additional efforts are needed to verify and fine-tune the model to comprehensively simulate the N cycle, especially losses by drainage water and gaseous emissions

Predicting Maize Theoretical Methane Yield in Combination with Ground and UAV Remote Data Using Machine Learning

The accurate, timely, and non-destructive estimation of maize total-above ground biomass (TAB) and theoretical biochemical methane potential (TBMP) under different phenological stages is a substantial part of agricultural remote sensing. The assimilation of UAV and machine learning (ML) data may be successfully applied in predicting maize TAB and TBMP; however, in the Nordic-Baltic region, these technologies are not fully exploited. Therefore, in this study, during the maize growing period, we tracked unmanned aerial vehicle (UAV) based multispectral bands (blue, red, green, red edge, and infrared) at the main phenological stages. In the next step, we calculated UAV-based vegetation indices, which were combined with field measurements and different ML models, including generalized linear, random forest, as well as support vector machines. The results showed that the best ML predictions were obtained during the maize blister (R2)–Dough (R4) growth period when the prediction models managed to explain 88–95% of TAB and 88–97% TBMP variation. However, for the practical usage of farmers, the earliest suitable timing for adequate TAB and TBMP prediction in the Nordic-Baltic area is stage V7–V10. We conclude that UAV techniques in combination with ML models were successfully applied for maize TAB and TBMP estimation, but similar research should be continued for further improvements

Relaunch cropping on marginal soils by incorporating amendments and beneficial trace elements in an interdisciplinary approach

In the EU and world-wide, agriculture is in transition. Whilst we just converted conventional farming imprinted by the post-war food demand and heavy agrochemical usage into integrated and sustainable farming with optimized production, we now have to focus on even smarter agricultural management. Enhanced nutrient efficiency and resistance to pests/pathogens combined with a greener footprint will be crucial for future sustainable farming and its wider environment. Future land use must embrace efficient production and utilization of biomass for improved economic, environmental, and social outcomes, as subsumed under the EU Green Deal, including also sites that have so far been considered as marginal and excluded from production. Another frontier is to supply high-quality food and feed to increase the nutrient density of staple crops. In diets of over two-thirds of the world's population, more than one micronutrient (Fe, Zn, I or Se) is lacking. To improve nutritious values of crops, it will be necessary to combine integrated, systems-based approaches of land management with sustainable redevelopment of agriculture, including central ecosystem services, on so far neglected sites: neglected grassland, set aside land, and marginal lands, paying attention to their connectivity with natural areas. Here we need new integrative approaches which allow the application of different instruments to provide us not only with biomass of sufficient quality and quantity in a site specific manner, but also to improve soil ecological services, e.g. soil C sequestration, water quality, habitat and soil resistance to erosion, while keeping fertilization as low as possible. Such instruments may include the application of different forms of high carbon amendments, the application of macro- and microelements to improve crop performance and quality as well as a targeted manipulation of the soil microbiome. Under certain caveats, the potential of such sites can be unlocked by innovative production systems, ready for the sustainable production of crops enriched in micronutrients and providing services within a circular economy

Limited effects of crop foliar Si fertilization on a marginal soil under a future climate scenario

Growing crops on marginal lands is a promising solution to alleviate the increasing pressure on agricultural land in Europe. Such crops will however be at the same time exposed to increased drought and pathogen prevalence, on already challenging soil conditions. Some sustainable practices, such as Silicon (Si) foliar fertilization, have been proposed to alleviate these two stress factors, but have not been tested under controlled, future climate conditions. We hypothesized that Si foliar fertilization would be beneficial for crops under future climate, and would have cascading beneficial effects on ecosystem processes, as many of them are directly dependent on plant health. We tested this hypothesis by exposing spring barley growing on marginal soil macrocosms (three with, three without Si treatment) to 2070 climate projections in an ecotron facility. Using the high-capacity monitoring of the ecotron, we estimated C, water, and N budgets of every macrocosm. Additionally, we measured crop yield, the biomass of each plant organ, and characterized bacterial communities using metabarcoding. Despite being exposed to water stress conditions, plants did not produce more biomass with the foliar Si fertilization, whatever the organ considered. Evapotranspiration (ET) was unaffected, as well as water quality and bacterial communities. However, in the 10-day period following two of the three Si applications, we measured a significant increase in C sequestration, when climate conditions where significantly drier, while ET remained the same. We interpreted these results as a less significant effect of Si treatment than expected as compared with literature, which could be explained by the high CO2 levels under future climate, that reduces need for stomata opening, and therefore sensitivity to drought. We conclude that making marginal soils climate proof using foliar Si treatments may not be a sufficient strategy, at least in this type of nutrient-poor, dry, sandy soil