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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]