Effect of biochar application as a component improving the retention properties of peat moss substrate

Physical and chemical properties of biochar from wood biomass indicate that it can be a valuable supplement to nursery substrates, mainly to improve sorption capacity as well as nutrient and water retention. The paper presents the results of a pilot experiment on the impact of biochar on the moisture content of peat moss substrate and its retention properties. The experiment was carried out in the autumn of 2017 at the Soil Water and Environmental Science laboratory at the University of Arizona, Tucson (USA). 15 cubic decimeter of peat substrate with grain size 2 mm and 0.70 kg biochar, with the same grain size, obtained as a result of pyrolysis (450−500°C) from Pinus ponderosa Dougl. Ex C.Lawson branches. The experimental series consisted of 25 black PP containers with a volume of 265 cm3 (5 replicates) filled with peat moss (control sample PM) and a mixture of peat and biochar in 10% (PMB10), 20% (PMB20), 30% (PMB30) and 50% (PMB50) share. After soaking of mixture, most of the water was retained by 50% and 30% peat samples with biochar, followed by samples in which the proportion of biochar was 20% and 10% respectively. The least water was retained by the sample with the pure peat moss substrate (PM) – on average 76.5 g which is 255.3% of the initial weight After 96 hours the water losses were the highest in the pure peat moss samples (44.2%), while the smallest were noted in PMB30 and PMB50 samples (fig. 2b). The favourable properties of the peat and biochar mixture in the range of moisture parameters were observed. In the PWB10 series, the average moisture was 5.2% higher than the peat sample, in the PWB20 the average humidity was 7.9% higher than the PM sample, in the PWB30 and PWB50 series the differences were larger: 15.0% and 14.2% respectively (fig. 4). The significant variation in physical parameters between the individual series was confirmed as well as the assumption of variance uniformity (tab. 3, fig. 4)