Recently, the bactericidal and fungicidal effects of plasma-activated water (PAW) have been confirmed for its application in agriculture. Although the PAW application is beneficial in plant growth, no information is available about processes induced by PAW in soil. This paper gives the first experimental results about PAW’s influence on selected physical and physical–chemical properties of soil. PAW was prepared using the dielectric barrier discharge (DBD) operating in the multistreamer mode at a frequency of 11 kHz. The total energy consumption was 60 J/ml. The obtained results show minimal changes in the natural water evaporation from the soil exposed to PAW, slower tap water absorption if a higher amount of PAW (16 doses per 10 ml to 90 g of the soil) is applied, as well as water retention in the soil of over 30%. The soil pH remains in the neutral range of values even at the highest applied PAW amount of 1.7 weight of soil, which represents the best conditions with respect to the plant growth. Thus, we can conclude that the PAW application, even at high amounts, has no negative influence on the physical and physical–chemical properties of soil and it can be safely applied in sustainable, environmentally friendly agriculture.

Utilization of plasma activated water (PAW) for plant growing is mainly connected with the treatment of seeds and subsequent stimulation of their germination. A potential of PAW is its relatively simple and low-cost preparation that calls for studying its wider application in plant production. For this purpose, a pot experiment was realized in order to prove effects of the foliar PAW application on maize growth. The stepped PAW foliar application, carried out in 7-day intervals, led to provable decrease of chlorophyll contents in leaves compared to the distilled water application. The PAW application significantly increased root electrical capacitance, but it had no provable effect on weight of the aboveground biomass. Chlorophyll fluorescence parameters expressing the CO₂ assimilation rate and variable fluorescence of dark-adapted leaves were provably decreased by PAW, but quantum yield of photosystem II electron transport was not influenced. A provably higher amount of nitrogen was detected in dry matter of plants treated by PAW, but contents of other macro- and micro-nutrients in the aboveground biomass of maize were not affected. Results of this pilot verification of the PAW application have shown a potential for plant growth optimization and possibility for its further utilization, especially in combination with liquid fertilizers.

Currently, there is an increasing emphasis on the use of renewable sources. The Czech Republic is no exception. There has been an increase in the number of biogas plants and composting plants. The main purpose of these facilities is to process organic wastes of various origins in order to utilize the waste, both for energy production and as soil fertility enhancers. Last but not least, the biogas station produces digestate, which could be further utilized. The present work deals with the assessment of the effect of digestate (doses of 220; 150 and 80 kg N ha⁻¹), mineral fertilizer (150 kg N ha⁻¹), and compost application (150 kg N ha⁻¹) on selected indicators of soil environment: (a) soil microbial activity (basal and substrate-induced respiration); (b) plant nutrient content (P, K, Ca, Mg); (c) leaching mineral N from the soil; and (d) production of plant biomass of model plant Lactuca sativa L. Furthermore, the work aims to assess the individual doses of digestate and to determine the optimal one. The above effects were studied within a pot experiment for 63 days in controlled conditions. There were significant differences in N_min leaching, which was significantly the highest in the variant with the application of a mineral fertilizer and lowest in variants with the application of digestate (variant 150 and 80 kg N ha⁻¹) and compost (150 kg N ha⁻¹). In terms of soil microbial activity, a significant effect of digestate application (150 kg N ha⁻¹) on basal respiration versus the mineral fertilizer application was found (difference > 20%). This dose of digestate also had the highest positive effect on substrate-induced respiration, proven against all other variants, except for the digestate application at 220 kg N ha⁻¹. Particularly, as compared with the mere application of mineral fertilizer, the application of digestate dose at 150 kg N ha⁻¹ had the best positive effect on plant biomass production (+20%). On the other hand, compost application most positively affected the increase in available contents of nutrients and thus long-term soil fertility. Therefore, the dose of 150 kg N ha⁻¹ digestate may represent an interesting alternative to increase actual soil fertility and thus to partially replace conventional mineral nutrition.

Biochar can increase the microbial activity of a soil and the seed yield of oilseed rape. We performed a field experiment to determine the effect of different doses of biochar and the impact of nutrient additions on microbial activity in soils with low pH (4.69). Different doses of biochar were applied to plots in 2016 (0 t/ha (control), 15 t/ha (B15), 30 t/ha (B30), or 45 t/ha (B45)), and fertilization was applied during 2019 (90 kg P/ha) and 2020 (50 kg N/ha, 80 kg P/ha, and 50 kg K/ha). Maize was grown in 2016, barley in 2017, maize in 2018, wheat in 2019, and winter oilseed rape in 2020. All analyses were carried out in 2020. Higher biochar doses led to reduced seed yield of oilseed rape and inhibition of microbial activity (cumulative soil respiration, dehydrogenase activity (DHA), and leaching of mineral forms of nitrogen). Notably, dehydrogenase activity was more than 60% lower in plots with the highest biochar dose. All doses of biochar increased the soil pH compared to the control (control: 4.51 ± 0.04, B15: 4.69 ± 0.04, B30: 5.06 ± 0.05, B45: 5.05 ± 0.04) but did not increase microbial activity or the seed yield of oilseed rape. Thus, application of biochar alone did not increase the seed yield of oilseed rape or soil microbial activities, although it did increase soil pH.

To investigate the different responses of crops to drought stress under field conditions of Central European Climate for selected crop rotations, a field experiment was conducted at a test site in the Czech Republic from 2014 to 2021. Depending on the crop, rainout shelters were placed in late spring and early summer to study the effects of drought in the final stages of crop development. Due to these rainout shelters and the associated lower water availability for the crops during the summer, a reduction in leaf area index, biomass and yield was observed. For example, a yield decrease of more than 30% was observed for spring barley, winter rape and winter wheat compared to conditions without rainout shelters. The reduction was 25% and 18% for winter rye and silage maize, respectively, under rainout shelters. Soil moisture played a significant role in yield, where a predictive model based on monthly soil moisture explained up to 79% (winter rape) of the yield variance.

Physical properties of soils are affected by many factors. These include the type of fertilizer used. An offer of fertilizers is currently extensive and new types are added, an example may be digestate, which is ranked among organic fertilizers according to Czech legislation. Changes in physical soil properties were monitored on a field trial, which were established on the place of Research grassland station Vatín (region Vysočina, the Czech Republic) in autumn 2013. The field trial comprised different variants of fertilization. Their effects were observed at different vegetation covers. In this paper, we focus on vegetation cover corn, fertilization variants: manure, mineral fertilizer (saltpetre ammonium with limestone) and digestate. The effect of fertilization was observed 3 times during the growing season 2014. It was in June, August and October. The results were obtained by the basic analysis of Kopecky rollers and it was from the depths of 0.05 m and 0.15 m (middle roller). The monitored soil properties were: bulk density, porosity, water retention capacity, maximum capillary water capacity and minimum air capacity. At all investigated physical soil properties there was a positive development during the growing season, with the exception of water retention capacity. The difference was found in the range of changes in various physical properties depending on the applied fertilizer.