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.

Fusarium head blight (FHB) is one of the most serious diseases of small-grain cereals worldwide, resulting in yield reduction and an accumulation of the mycotoxin deoxynivalenol (DON) in grain. Weather conditions are known to have a significant effect on the ability of fusaria to infect cereals and produce toxins. In the past 10 years, severe outbreaks of FHB, and grain DON contamination exceeding the EU health safety limits, have occurred in countries in the Baltic Sea region. In this study, extensive data from field trials in Sweden, Poland and Lithuania were analysed to identify the most crucial weather variables for the ability of Fusarium to produce DON. Models were developed for the prediction of DON contamination levels in harvested grain exceeding 200 µg kg⁻¹ for oats, spring barley and spring wheat in Sweden and winter wheat in Poland, and 1250 µg kg⁻¹ for spring wheat in Lithuania. These models were able to predict high DON levels with an accuracy of 70–81%. Relative humidity (RH) and precipitation (PREC) were identified as the weather factors with the greatest influence on DON accumulation in grain, with high RH and PREC around flowering and later in grain development and ripening correlated with high DON levels. High temperatures during grain development and senescence reduced the risk of DON accumulation. The performance of the models, based only on weather variables, was relatively accurate. In future studies, it might be of interest to determine whether inclusion of variables such as pre-crop, agronomic factors and crop resistance to FHB could further improve the performance of the models.

In this work, we studied the impact of harvesting time on Fusarium mycotoxin occurrence in spring wheat and the effect of mycotoxin contamination on the quality of these grains. The spring wheat grains (Triticum aestivum L.) were collected in 2016–2018 when the crop had reached full maturity, 10 ± 2 days and 17 ± 3 days after full maturity. The grain samples were analyzed for Fusarium infection and co-contamination with mycotoxins deoxynivalenol (DON), zearalenone (ZEA), and T-2 toxin (T-2), as well as the quality of the wheat grains (mass per hectolitre, contents of protein, starch, ash and fat, particle size index (PSI), falling number, sedimentation, wet gluten content, and gluten index). The occurrence of Fusarium spp. fungi and the mycotoxins produced by them in the grains was mostly influenced by the harvesting time and meteorological conditions. The correlations between Fusarium species and the mycotoxins produced by them in the grains of spring wheat showed F. graminearum to be a dominant species, and as a result, higher concentrations of DON and ZEA were determined. The co-occurrence of all the three mycotoxins analyzed (deoxynivalenol, zearalenone, and T-2 toxin) was identified in wheat. In rainy years, a delay in harvesting resulted in diminished grain quality of spring wheat, as indicated by grain mass per hectolitre and falling number. Negative correlations were found in highly contaminated grains between mycotoxins (DON, ZEA, and T-2) and falling number and grain mass per hectolitre values.

Given the growth in the number of biogas power plants and the increase in the generation of waste from energy production, it is relevant to study the sustainable nature of this waste. Digestate is a product of the anaerobic digestion process, and is a valuable bio-fertilizer containing organic matter and nutrients necessary for agricultural plants’ growth. The study showed that different rates of liquid and solid phases of anaerobic digestate influenced the contents of carbon and nitrogen in genetically young soil in alluvial deposits—Fluvisol. The application of solid digestate (SD) considerably increased soil organic carbon content (SOC) in the 0–10 cm soil layer; however, SOC did not reach the 20–30 cm layer. Liquid digestate (LD) significantly increased SOC in the deeper layers. The levels of mineral nitrogen (N_min) and water extractable organic carbon (WEOC) increased in the 0–10 cm soil layer soon after fertilization with LD and SD. The mobile components of the soil (N_min and WEOC) were characterized by high variability during the growing season. Within the 2-month period, their concentrations decreased drastically and were close to those of unfertilized soil. The research indicates that anaerobic digestate had a greater effect on mobile forms of carbon and nitrogen in the soil than on their total amounts.

The common smut of corn, caused by Ustilago maydis, reduces the yield and quality of maize forage. When heavy infestations of corn smut occur, grain yields can be so severely decreased that the most viable economic alternative may be to harvest and ensile the crop. Only a couple of studies have attempted to investigate the influence of aerobic exposure on the nutritive value and aerobic stability of silage, which is prepared from smut-infected maize. In this study, individual whole corn plants were harvested by hand. The plants were distributed into three treatments: 0% infected, 50% infected, and 100% infected. The fresh forage was ensiled in triplicate for a 90-day period. Aerobic exposure lasted for 28 days. Samples were taken on the day of opening and on the 3rd, 7th, 14th, and 28th days. Near infrared spectroscopy (NIRS) calibration equations were used for the prediction of qualitative indicators. Silage prepared from 100% smut-infected maize had comparatively poor quality with dry matter loss, increasing pH and the low amount of starch. It was also distinguished with significant temperature increases from days 15 to 18 of aerobic exposure. Silage prepared from 50% smut-infected maize did not show significant quality changes over the period of the experiment, although it had inferior quality compared to the silage prepared from smut-free maize. While silage prepared from smut-infected maize had an overall worse quality than silage prepared from non-infected maize, it should not have an adverse effect on livestock health or production.

The aim of this study was to investigate whether, in the context of a higher incidence of Ustilago maydis and Fusarium spp. at optimal and delayed harvest times, a higher incidence of mycotoxin contamination in maize grains could be expected. The field experiment was carried out at the Lithuanian Research Centre for Agriculture and Forestry experimental fields over three consecutive years (2020–2022). Two maize hybrids (Duxxbury and Lapriora) with different FAO numbers were used. The experimental design in the field was a randomized complete block design. Harvesting took place at three different times: first at physiological maturity, and then 10 (±2) and 20 (±2) days after the first harvest. Each hybrid had four repetitions at different harvest times. The U. maydis infection was only detected in 2021 and after the first harvest cobs were further divided into four different groups with four repetitions: healthy cobs, cobs visually infected with Fusarium spp., cobs visually infected with common smut, and cobs visually infected with both pathogens. No U. maydis-damaged maize cobs were found in 2020 and 2022. The levels of Fusarium microscopic fungi in maize grains were also from 4 to 16 times higher in 2021 than in 2020 and 2022. Harvest delays in 2020 led to a significant deoxynivalenol concentration increase in the Duxxbury hybrid and an HT-2 concentration increase in the Lapriora hybrid. In 2021, deoxynivalenol, 3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, and HT-2 concentrations significantly rose in both hybrids, but the T-2 concentration significantly increased only in the Lapriora hybrid. Deoxynivalenol concentrations were, respectively, 110 and 14.6 times higher than in cobs only infected with Fusarium spp. or U. maydis. Concentrations of 15-acetyl-deoxynivalenol were, respectively, 60, 67, and 43 times higher than in asymptomatic cobs and cobs only infected with Fusarium spp. or U. maydis. Cobs contaminated with both pathogens also had higher concentrations of 3-acetyl-deoxynivalenol. T-2 and HT-2 were detected in maize grains harvested from cobs infected only with Fusarium spp. The presence of U. maydis and Fusarium fungi in maize cobs, along with harvest delays, led to significant increases in mycotoxin concentrations, highlighting the importance of timely harvesting and pathogen management to mitigate mycotoxin contamination in maize grains.