Effect of wheat and Miscanthus straw biochars on soil enzymatic activity, ecotoxicity, and plant yield

The variety of technological conditions and raw materials from which biochar is produced is the reason why its soil application may have different effects on soil properties and plant growth. The aim of this study was to evaluate the effect of the addition of wheat straw and Miscanthus giganteus straw (5 t DM ha-1) and biochar obtained from this materials in doses of 2.25 and 5 t DM ha-1 on soil enzymatic activity, soil ecotoxicity, and plant yield (perennial grass mixture with red clover). The research was carried out under field conditions on soil with the granulometric composition of loamy sand. No significant effect of biochar amendment on soil enzymatic activity was observed. The biochar-amended soil was toxic to Vibrio fischeri and exhibited low toxicity to Heterocypris incongruens. Application of wheat straw biochar and M. giganteus straw biochar in a dose of 5 t DM ha-1 contributed to an increase in plant biomass production by 2 and 14%, respectively, compared to the soil with mineral fertilisation. Biochars had a more adverse effect on soil enzymatic activity and soil ecotoxicity to H. incongruens and V. fischeri than non-converted wheat straw and M. giganteus straw, but significantly increased the grass crop yield

Effects of Different Tillage Intensities on Physicochemical and Microbial Properties of a Eutric Fluvisol Soil

The physicochemical and microbial properties of soil under long-term monoculture of winter wheat were studied to assess the effects of two tillage systems of different intensities: reduced (RT) and conventional (CT). The research was carried out on an 18-year-old experimental field at Grabów (eastern Poland) between 2018 and 2020. The RT (ploughless) and the CT (mouldboard ploughing) systems with machine operating depths of up to 10 and 25 cm, respectively, were used. The analysed parameters were as follows: soil texture, pH, readily dispersible clay content (RDC), soil organic matter (SOM), carbon from particulate organic matter (POM-C), hot- and cold-water-extractable organic carbon (HWEC, CWEC) and nitrogen (HWEN, CWEN), soil basal respiration (SBR), microbial biomass carbon (MBC) and nitrogen (MBN), nitrification potential (NP), dehydrogenases (DEH), and acid (ACP) and alkaline (ALP) phosphatases activities. Several single soil quality indices, including: metabolic (qCO2) and microbial (MicQ) quotients, enzymatic pH level indicator (EpHI), stratification ratio (SR), and metabolic potential index (MP) were calculated. The use of RT resulted in increased SOM and, therefore, in decreased RDC and increased values of soil stability, POM-C, HWEC, CWEC, HWEN, CWEN, MBC, and MBN in relation to CT. The MicQ, EpHI, SR, and MP well reflected the effects of RT and CT systems on soil and appeared to be useful in soil quality assessment. The results showed the beneficial effects on soil of the less intensive RT system in comparison with CT. Statistical analysis showed the significance of differences between tillage systems and interrelationships between the studied soil quality parameters