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Biochar and zeolite are widely used in the remediation of soil contaminated with toxic heavy metals. However, the interaction of these amendments and their effects on grass productivity have not been comprehensively summarized. The aim of this study was to investigate the biological effects of zeolite and biochar used as soil amendments in the process of remediating soil contaminated with Cd, Pb and Zn. In a pot experiment, the following treatments were applied: zeolite, biochars produced at temperatures of 350 °C and 550 °C, mixtures of biochars and zeolite, and a control treatment without any amendments. The soil amendments were tested on two grass species: tall fescue (Festuca arundinacea Schreb.) and cocksfoot (Dactylis glomerata L.). The root morphometric parameters and aboveground production were determined in 2017 and 2018. Higher biomass production was observed in the tested grasses in the treatments with zeolite alone (0.229 kg DM m−2) or mixed with the biochars (0.239 kg DM m−2) than in control treatment (0.029 kg DM m−2). Zeolite used in contaminated soil significantly affected root biomass and root morphology parameters. Zeolite application resulted in significantly higher root biomass (2.30 mg cm−3) and root length (76.61 cm cm−3) than those in the treatments without zeolite (0.29 mg cm−3 and 6.90 cm cm−3). Biochar as a soil amendment did not affect most root morphometric parameters. The application of biochars only slightly reduced the root diameter of cocksfoot. The root diameter of tall fescue was similar in all treatments (0.075 mm) except the control (0.063 mm) and biochar 550 treatments (0.067 mm), in which slightly thinner roots were observed. [ABSTRACT FROM AUTHOR]

Organic and inorganic soil amendments are used to increase crop yields and fertilizer efficiency, as well as to improve the physical and biological properties of soil, increase carbon sequestration, and restore contaminated and saline soils. The present study aimed to evaluate the effect of various zeolite composites mixed with either lignite or leonardite on the biomass production of spring wheat and rapeseed and their root morphology. A pot experiment involved the application of the following treatments: zeolite-carbon, zeolite-vermiculite composites, both mixed with lignite or leonardite, and a control treatment with no amendments. Inorganic composites were applied in a dose of 3% and 6%. The study also included an analysis of the root morphometric parameters and aboveground biomass of spring wheat and rapeseed. The lowest productivity was observed when both crops were not enriched with fertilizers or other amendments, 24.92 g per pot and 29.83 g per pot for spring wheat and rapeseed, respectively. The application of mineral fertilizers in combination with zeolite-carbon composite gave the highest aboveground biomass of spring wheat, 110.11 g per pot. Both zeolite-carbon and zeolite-vermiculite composites modified the morphological parameters of roots, with the control treatment showing the lowest root length and dry matter. Although mineral fertilization was found to have a positive impact root development in relation to untreated control, the treatment amended with zeolite-carbon composite and leonardite exhibited the highest root length and biomass of spring wheat. No other soil amendments improved the properties of rapeseed roots. [Display omitted] • Organic/inorganic composites were applied in spring wheat and rapeseed. • The lowest yield were obtained for Control. • Highest productivity was for mineral fertilization with zeolite-carbon composite. • Zeolite-carbon and zeolite-vermiculite increased root length and biomass. • The highest root length was for zeolite-carbon with leonardite. [ABSTRACT FROM AUTHOR]

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 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. [ABSTRACT FROM AUTHOR]

The objective of this research was to determine the effect of straw and biochar amendment on the root system morphology and aboveground biomass of a red clover/grass mixture (Lolium. perenne L., Phleum pratense L., Festuca pratensis Huds., F. arundinacea Schreb., L. multiflorum L., L. westerwoldicum Breakw., Trifolium pratense L.). A grassland experiment was conducted from 2014 to 2018. Straw was collected from miscanthus (Miscanthus × giganteus), winter wheat (Triticum aestivum L.), and biochar was produced from the biomass of those species. The following treatments were applied: wheat straw at a rate of 5 t ha−1 (WS), miscanthus straw at a rate of 5 t ha−1 (MS), wheat biochar at a rate of 5 t ha−1 (WBH), wheat biochar at a rate of 2.25 t ha−1 (WBL), miscanthus biochar at a rate of 5 t ha−1 (MBH), and miscanthus biochar at a rate of 2.25 t ha−1 (MBL). A treatment with mineral fertilizer but without organic amendments (MCTR) was used, and a control treatment (CTR) without mineral fertilizer and without any amendments was also tested. The botanical composition and the aboveground yields were determined. The roots were sampled in 2018, and the root morphology parameters were determined using an image analysis system. The applied soil amendments resulted in increased root lengths, surface areas, volumes, and mean root diameters. There were no differences between the treatments with different feedstock types (miscanthus vs. wheat), materials (straw vs. biochar), or amendment rates (5 vs. 2.25 t ha−1). The resulting root system characteristics were reflected in the aboveground biomass productivity. The soil amendments, i.e., the straw and biochar, significantly increased the productivity in comparison to that of the control treatment. However, these differences were noticed only during the first and second cuts. Recommended practice in grassland management is to improve soil with straw. The conversion of straw into biochar does not provide a better effect on grassland productivity. [ABSTRACT FROM AUTHOR]

The use of straw as a soil amendment is a well-known and recommended agronomy practice, but it can lead to negative effects on the soil and crop yield. It has been hypothesized that many problems related to the burying of straw can be overcome by pyrolyzing it. The objective of this study was to determine the effect of straw and its biochar on the biomass production of perennial ryegrass. A pot-based experiment was conducted with three factors: (i) the crop species used as feedstock, (ii) raw or pyrolyzed organic material, and (iii) the rate of organic amendments. The soil in the pots was amended with straw and biochar produced from Miscanthus (Miscanthus × giganteus) or winter wheat (Triticum aestivum L.). After soil amendment application, perennial ryegrass (Lolium perenne L.) seeds were sown. During two years of the experiment, the perennial ryegrass above-ground biomass production and root biomass and morphology parameters were determined. Straw and biochar resulted in higher perennial ryegrass above-ground biomass compared with that of the non-fertilized control. However, straw amendment resulted in lower plant yields of above-ground biomass than those of the biochar treatments or the mineral fertilizer control treatment. The feedstock type (Miscanthus or wheat) significantly affected the perennial ryegrass yield. No difference was observed among wheat and Miscanthus biochar, while among straws, Miscanthus resulted in lower perennial ryegrass productivity (the higher rate of straw and biochar as soil amendments resulted in relatively high perennial ryegrass productivity). The organic amendments resulted in relatively high root biomass and length. The root:shoot ratio was lower in the treatments in which biochar was used, whereas feedstock species and amendment rate were not statistically significant for any of the root biomass and morphometric parameters. The results suggest that the use of pyrolyzed straw can be a reliable strategy instead of straw, increasing ryegrass growth and productivity. [ABSTRACT FROM AUTHOR]

Biochar is a valuable soil amendment and is recognized to have a positive effect on the crop yield, soil quality, nutrient cycling, and carbon sequestration. However, the effect depends on biochar characteristics, doses, and soil properties. This paper reports the study on determination of the effect of different rates of biochar based on their size fractions on water retention characteristic of sand-based rootzone mixture characteristic for natural turfgrass rootzone. The pot experiment was established using a soil with the texture of loamy sand. Mixtures of biochar and soil were prepared in March 2014. Biochar was produced using the straw of two species, namely miscanthus and winter wheat, by pyrolysis process at a temperature of 300 °C for 15 min with limited air access. Then, biochar particles were separated into three size fractions as follows: 0–500 μm, 500–1000 μm, and 1000–2000 μm. The following four biochar rates were used in this experiment: 0.5%, 1%, 2%, and 4%. The results indicated that biochar application significantly improved the physical properties of the tested sandy soil. The basic soil physical parameters, such as bulk density and total porosity, were not only dependent on the rate but also on the size of the biochar. Small particles of biochar reduced the volume of soil pores in diameter below 0.5 μm but increased the volume of larger pores with a diameter 0.5–500 μm. Biochar application increased the available water content (AWC), especially when the finest fraction was used (0.064 cm 3 cm − 3 ). Biochar made of miscanthus was characterized by higher AWC (0.056 cm 3 cm − 3 ) than that made of winter wheat (0.050 cm 3 cm − 3 ). In the present study, the soil water repellency was increased by biochar application, but it was still classified as non-repellent. [ABSTRACT FROM AUTHOR]