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Combining inorganic and organic soil amendments with mineral fertilizers is promising for soil quality enhancement in modern agronomy systems. In this research, four main organic components were used in fertilizer formulations: coconut coir, biochar, lignite, and leonardite (enriched with microelements, tryptophan, and bacterial metabolic products). The treatments were assigned to the completely randomized design with a control object, without any soil amendments, and with only mineral fertilization. Aboveground biomass and root characteristics of maize (root length density, mean root diameter, root surface area density, specific root length, root volume density, and root dry matter) and water retention and characteristics of soil pores were determined. Compared to the control, all fertilizer formulations applied deteriorated the water retention properties of the soil. The highest plant available water content value was obtained for the control without any fertilizers. The addition of organic fertilizer formulations consisting of coconut coir, biochar, lignite, leonardite, microelements, tryptophan, and metabolic products of Pseudomonas sp. and Bacillus subtilis did not play a significant role in improving soil physical characteristics. The lowest productivity was characterized for maize without any fertilizers and amendments. All soil organic amendments resulted in lower yields than the one with only mineral fertilization. The highest root dry matter was obtained when lignite and leonardite were used as main components. Organic amendments can be recommended for soil bioregeneration, but their main effect on maize productivity is attributed to the mineral component. [ABSTRACT FROM AUTHOR]

Durum wheat is commonly used in various food industry industries and cultivated worldwide. A serious problem with the species cultivation is its capability to accumulate cadmium (Cd) in the grains. The aim of this study is to investigate whether antioxidant activity may be used as a marker of Cd tolerance in durum wheat. The experiment involved three durum wheat genotypes/lines differing in salt tolerance. The plant response to Cd was appraised based on the activity of ascorbate–glutathione (AsA–GSH) cycle enzymes, ascorbate-to-dehydroascorbate ratio, reduced-to-oxidized glutathione ratio (GSH:GSSG), as well as Cd content in the seeds. The highest activity of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione reductase was noted in control plants of salt-sensitive cultivar “Tamaroi.” In the presence of Cd, activity of these enzymes was considerably reduced. “Tamaroi” plants demonstrated also the highest Cd content in the grain. In conclusion, we identified the cultivar “Tamaroi” as most susceptible to cadmium, and the level of durum wheat sensitivity to the element can be evaluated based on a significant decrease in the activity of AsA–GSH cycle enzymes and GSH:GSSG ratio.

Both inorganic and organic soil amendments serve as pivotal tools for augmenting crop yield and optimising fertilisation efficacy, while enhancing soil physical and biological characteristics, bolstering carbon sequestration, and remedying soil degradation caused by pollutants and salinity. This study was carried out with the specific objective of discerning the impact of various zeolite composites and their mixtures with lignite or leonardite on maize biomass output. To achieve this aim, the following treatments were applied in a controlled pot experiment: zeolite/carbon and zeolite/vermiculite composites mixed with lignite or leonardite, and a control treatment devoid of any amendments. Subsequent analysis encompassed the root morphometric parameters and maize aboveground production. The lowest productivity was characterised for maize without any fertilisers and amendments. The highest aboveground biomass of maize straw was obtained when only mineral fertilisation was applied. Both aboveground and root biomass were at the same level, notwithstanding the soil amendments, zeolite composites or organic amendments. Root morphological parameters, including root dry matter, root length, root surface area, and volume, were influenced by the addition of zeolite/carbon and zeolite/vermiculite composites with organic component. Our research shows the beneficial effect of the applied additives on some morphological properties of the roots. Zeolite/vermiculite composite application increased root surface area and root volume. [ABSTRACT FROM AUTHOR]

Due to the indisputable significance of humus in many biochemical processes as well as its increasing deficit particularly in light soils, alternative sources of substrates for the reproduction of this constituent should be sought. The aim of this study was to evaluate the effect of the addition of wheat straw and wheat straw biochar (in four rates) on quantitative and qualitative humus parameters. The following properties were determined in soil: pH, organic carbon, total nitrogen, humic and fulvic acids, carbon in the extract, non-hydrolysing carbon and spectrophotometric indexes for solution of humic acids including A2/6, A2/4, A4/6. After applying 1% and 2% additions of biochar to the soil, the Corg soil content significantly increased compared to the same doses of thermally unconverted straw. After 254 days of incubation, the addition of biochar to soil at higher doses, decreased the share of humic acid carbon (CHA, CFA) in the Corg content compared to treatments without organic additions and WS treatment. The nonhydrolysing carbon soil content was significantly increased by treatments with 1% and 2% additions of WSB, which indicates greater stabilisation of humus compounds and, at the same time, lower CO2 emission. Soil humic acids amended by treatment with biochar, especially at 1% and 2% doses, were characterised by lower A2/6 and A2/4 ratios. Recognition of changes that may occur in the quantitative and qualitative composition of soil humus after the application of biochar may in the future be helpful information for determining appropriate biochar dose.

The aim of this research was to determine the effect of thermal conversion temperature and plant material addition to sewage sludge on the PAHs content and the activity of selected γ-radionuclides in biochars, and to conduct an ecotoxicological assessment. The pyrolysis of the mixtures of sewage sludge and plant materials at 300°C and such temperature caused an increase in the contents of 2- and 3-ring hydrocarbons. During the pyrolysis of organic materials at 600°C, the amount of the following compounds was reduced in biochars: benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3c,d]pyrene, dibenzo[a,h]anthracene, and benzo[g,h,i]perylene. Among γ-radioisotopes of the elements, natural radiogenic isotopes were dominant. 137Cs was the only artificial radioactive isotope. The pyrolysis of the mixtures of municipal sewage sludge and plant materials revealed that isotope 40K had the highest radioactive activity. In the case of other analysed nuclides, activities of 212Pb, 214Pb, 214Bi, and 137Cs were determined after the sample pyrolysis. The extracts from the mixtures of sewage sludge and plant materials were non-toxic to Vibrio fischeri.

The impact of lignite and leonardite combined with a NaX-C composite on the abundance of selected groups of culturable micro-organisms in soil contaminated with Pb, Cd and Zn was tested. For this purpose, a 7-month incubation experiment and two-year pot experiments were conducted. The pattern of both experiments was analogous and included: soil without fertilization (C); soil fertilized with NPK mineral fertilizers (MF); soil with NPK + 3 or 6% lignite (MF+CW3%, MF+CW6%) and 3% zeolite-carbon composite (NaX-C); soil with NPK + 3 or 6% leonardite (MF+CL3%, MF+CL6%) and 3% zeolite-carbon composite (NaX-C). The test plant in the pot experiment was the Kosynier variety of maize. The soil material was used to estimate the abundance of general bacteria, mold fungi, actinomycetes (actinomycetales), ammonification bacteria and bacteria from the Azotobacter genus. The study found that the application of lignite and leonardite combined with a NaXC composite had generally contributed to a significant increase in the total nitrogen content and a decrease in the total carbon content in soil in the pot experiment. In general, the mineral-organic mixtures had a stimulating effect on the analyzed groups of soil microorganisms in both experiments, but the dominant groups in the pot experiment were total bacteria and ammonifying bacteria, while in the incubation experiment, fungi and actinomycetes were the prevalent groups. An RDA analysis indicated that mold fungi, bacteria, actinomycetes and amminofers were positively correlated with the EC, total nitrogen and carbon. [ABSTRACT FROM AUTHOR]