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This work presents results from a field experiment which was focused on the impact of the drought period on microbial activities in rhizosphere and non-rhizosphere soil. To demonstrate the effect of drought, the pot experiment lasted from 2012 to 2015. Fifteen lysimeters (plastic containers) were prepared in our area of interest. These lysimeters were filled with the subsoil and topsoil from this area and divided into two groups. The first group consisted of two variants: V1 (control) and V2 (84 kg N/ha), which were not stressed by drought. The second group consisted of three variants, V3 (control), V4 (84 kg N/ha), and V5 (84 kg N/ha + 1.25 L lignohumate/ha), which were stressed by drought every year of the experiment for 30 days. Changes in the soil moisture content caused by drought significantly affect the growth of Deschampsia caespitosa L., the microbial activity, and the soil's capacity to retain nutrients. The measured basal respiration and dehydrogenase activity values confirm the significant effect of drought on microbial activity. These values were demonstrably higher in the period before drought simulation by more than 60%. On the other hand, significant differences between microbial activities in the rhizosphere and non-rhizosphere soil were not found. We did not find a clear effect of drought on the formation of soil water repellency.

In this paper, a possible use of white sweet clover (Melilotus albus Med.) for phytoremediation was assessed. The plants were grown on soils with naturally occurring concentrations of potentially toxic elements (PTEs). First, the content of PTEs was determined in plant biomass and in soil samples using: (a) Optical emission spectrometry with inductively coupled plasma to determine Sb, As, Cd, Cu, Ni, Pb, and Se, and (b) thermal decomposition, amalgamation, and atomic absorption spectrometry to determine Hg. The effectiveness of Melilotus albus Med. (M. albus) for phytoremediation was evaluated using the bioconcentration factor (BCF). The phytoextraction potential of M. albus was determined using bioaccumulation factor (BAC) and translocation factor (TF) values. The highest concentration of PTEs in roots was detected for zinc (10.56 mg/kg of dry weight, DW) and copper (5.128 mg/kg of DW). Similarly, the highest concentration in above-ground parts of the plant was detected for zinc and copper (12.638 and 4.0 mg/kg of DW, respectively). Although the values were relatively high, the effectiveness of the absorption of these PTEs by plant biomass from the soil was relatively very low. BAC and BCF were always lower than 1. On the other hand, the results suggested that M. albus effectively transports PTEs (only for Zn, Pb and Hg) from roots to shoots, because TF was always higher than 1. However, the accumulation of PTEs from soils with a natural abundance of PTEs was not excessive in comparison to conventional maize silage. Therefore, there is no potential risk of biomethane production in biogas plants when biomass from M. albus is used., info:eu-repo/semantics/openAccess

Mycotoxins can pose a threat to biogas production as they can contaminate the feedstock used in biogas production, such as agricultural crops and other organic materials. This research study evaluated the contents of deoxynivalenol (DON), zearalenone (ZEA), fumonisin (FUM), and aflatoxin (AFL) mycotoxins in maize silage prior to it being processed in a biogas plant and in digestate produced at the end of the anaerobic digestion (AD) process. In the experiment, three samples of silage were collected from one silage warehouse: Variant 1 = low contamination, Variant 2 = medium contamination, and Variant 3 = heavy contamination, which were subjected to investigation. A significantly reduced biogas production was recorded that was proportional to the increasing contamination with molds, which was primarily due to the AD of silage caused by technologically erroneous silage treatment. The AD was connected with changes in silage composition expressed by the values of VS content, sugar content, lactic acid content, acetic acid content, and the ratio of lactic acid content to acetic acid content. The production of biogas and methane decreased with the increasing contents of NDF, ADF, CF, and lignin. The only exception was Variant 2, in which the content of ADF, CF, and lignin was lower (by 8-11%) than that in Variant 1, and only the content of NDF was higher (by 9%) than that in Variant 1. A secondary factor that also correlated with changes in the composition of the substrate was the development of undesirable organisms, which further contributed to its degradation and to the production of mycotoxins. It was also demonstrated in this study that during the AD process, the tested mycotoxins were degraded, and their content was reduced by 27-100%. Only the variant with low mold contamination showed a DON concentration increase of 27.8%., info:eu-repo/semantics/openAccess

The presented study deals with the use of legumes intercropped with maize for the production of biogas from silage. The main goal was to find out whether silages made from mixed cultures can be used in biogas production and how the use of such silages affects qualitative and quantitative parameters of the fermentation process compared with the pure maize silage. Variants prepared were pure cultures of maize, bean, lupin, and white sweet clover. In addition, mixed cultures were prepared of maize and individual legumes. Measured values showed that in terms of dry matter (DM) yield, mixed culture silages are almost of the same or even better quality than silage made from the maize monosubstrate. Compared with the maize monoculture silage, the presence of white lupine, white sweet clover, and broad bean in silages statistically significantly increased the content of DM, ash, and acid detergent fiber (by more than 5%). Bean and lupine in mixed silages with maize significantly increased the content of lipids (on average by more than 1.2%). Legumes in silages were significantly decreasing contents of neutral detergent fiber, crude protein, and starch. Production of biogas from silages of maize monosubstrates and mixed substrates of maize with white lupin, maize with white sweet clover, and maize with broad bean was directly proportional to the content of CAR and starch in these substrates. A perspective variant was the mixed substrate of maize and sweet clover from which biogas production was only 6% lower than that from conventional maize silage. The highest yield was recorded in the maize monosubstrate (0.923 m3/kgVS). Variants of mixed substrates had a yield ranging from 0.804 to 0.840 m3/kgVS.

The presented research deals with the effect of plot size changes on the crop yield. Three plots were chosen in a company engaged in conventional agriculture, on which yields were monitored from 2019 using yield maps. In 2020, the plots (initial size > 30 ha) were divided into different parts sized < 30 ha. In 2021, these newly arisen parts of the plots were harvested. Changes in the yield of grown crops were analysed using yield maps acquired by the harvesting machines. Relative yields (%) and absolute yields (t/ha) were determined on all experimental land parts arising from the initial plots' division. The values were then compared with yields recorded before the division of individual plots using zonal statistics. Measured relative yield values clearly show (P < 0.05) that the division of plots resulted in the increased heterogeneity of crop yields. On the initial plots as well as on the newly arisen plots, the relative yield was divided into the following categories: < 70, 70-85, 85-95, 95-105, 105-115, 115-130 and > 130%, with the value of 100% representing average yield. The analysis of measured yield data showed that the division of plots into smaller parts resulted in an uneven yield distribution because if a divided plot was heterogeneous in terms of yield levels, a cumulation of "higher yield levels (> 100%)" could have occurred in one specific newly arisen plot at the expense of another one. Moreover, new marginal parts of lands came into being during the division of larger soil complexes, and hence zones with potentially reduced yields.

Research of new input raw materials for biogas plants is a very actual topic. There are only a very few studies dealing with the possibility of using silage prepared from the above-ground parts of the Jerusalem artichoke (Helianthus tuberosus L.) and maize (Zea mayse L.) for methane production. This study deals with the determination of methane production and methane content in biogas during the fermentation of maize silage with dissimilar additions of the biomass of the Jerusalem artichoke (JA). Except for the effect of the JA's addition on the yield of methane, we also studied its potential influence on the inhibition of the process of anaerobic digestion and the bacterial and methanogenic archaeal composition of anaerobic digestate. There were five model silages prepared; two of them contained only maize or JAs, and the remaining three were mixtures of maize and JA silages (30%wt; 50%wt and 70%wt). The fermentation tests showed that the JA addition (from 30 to 70%wt) resulted in the production of biogas decreasing, on average, by 15%. Based on the performed metagenomic analysis, we cannot confirm an essential influence of JA biomass addition on the composition of the community of microorganisms during fermentation., info:eu-repo/semantics/openAccess

Suitability of the vegetation indices of normalized difference vegetation index (NDVI), blue normalized difference vegetation index (BNDVI), and normalized difference yellowness index (NDYI) obtained by means of UAV at the flowering stage of oil seed rape for the prediction of seed yield and usability of these vegetation indices in the identification of anomalies in the condition of the flowering growth were verified based on the regression analysis. Correlation analysis was performed to find the degree of yield dependence on the values of NDVI, BNDVI, and NDYI indices, which revealed a strong, significant linear positive dependence of seed yield on BNDVI (R = 0.98) and NDYI (R = 0.95). The level of correlation between the NDVI index and the seed yield was weaker (R = 0.70) than the others. Regression analysis was performed for a closer determination of the functional dependence of NDVI, BNDVI, and NDYI indices and the yield of seeds. Coefficients of determination in the linear regression model of NDVI, BNDVI, and NDYI indices reached the following values: R2 = 0.48 (NDVI), R2 = 0.95 (BNDVI), and R2 = 0.90 (NDYI). Thus, it was shown that increased density of yellow flowers decreased the relationship between NDVI and crop yield. The NDVI index is not appropriate for assessing growth conditions and prediction of yields at the flowering stage of oil seed rape. High accuracy of yield prediction was achieved with the use of BNDVI and NDYI. The performed analysis of NDVI, BNDVI, and NDYI demonstrated that particularly the BNDVI and NDYI indices can be used to identify problems in the development of oil seed rape growth at the stage of flowering, for their precise localization, and hence to targeted and effective remedial measures in line with the principles of precision agriculture., info:eu-repo/semantics/openAccess

The effect of coating the seed of clover crops by water absorbing seed process (WASP) technology pelletization on its germination capacity was studied in conditions of diverse drought intensities simulated by different concentrations of polyethylenglycol (PEG) 8000 solution. Drought resistance was monitored in the seed of five fodder clover species: Anthyllis vulneraria L., Medicago lupulina L., Trifolium repens L., Melilotus albus Medik. and Onobrychis viciifolia Scop. In the seed of given plant species, germination capacity was determined along with the share of dead and hard seeds. Although the coating significantly (p < 0.05) affected the drought resistance of seeds, the germination capacity increased only in conditions of milder drought (simulation with PEG: 0.1-0.3 mol). With the increasing intensity of drought induced by higher PEG concentrations (0.4-0.7 mol) the number of germinable seeds demonstrably decreased and the number of dead seeds increased in the coated seed as compared with the uncoated seed. The coated seed can be appropriate for use in M. lupulina, M. albus and T. repens, while the uncoated seed can be used in A. vulneraria and O. viciifolia.

Luskovino-obilné směsky (LOS) mají v zemědělství dlouhou tradici jako součást osevního fotopostupu na orné půdě a zlepšení krmivové základny. LOS představují výbornou předplodinu v osevním postupu, mají pozitivní vliv na kvalitu půdy, jsou odolnější proti chorobám a škůdcům, potlačují plevely a obohacují půdu o dusík. Jedná se o celou řadu otázek, od volby druhů a odrůd plodin a jejich vzájemného poměru při pěstování přes experimentální ověření vlivu na výskyt chorob, škůdců a plevelů, až po kvalitu a výživnou hodnotu produkce a ekonomiku. Zkušeností a poznatků s pěstováním LOS v podmínkách konvenčního zemědělství je poměrně velké množství, naproti tomu prakticky využitelných a experimentálně ověřených poznatků v podmínkách ekologického zemědělství je naprostý nedostatek. Tento stav dal podnět k formulaci dvou výzkumných projektů, které experimentálně ověřují využití LOS v ekologickém zemědělství na vybraných ekofarmách v ČR a jejichž průběžné výsledky jsou shrnuty v této publikaci. Tato publikace je snahou o souhrn všech dosud známých informací pro praxi.