Effect of Biochar Type on Macronutrient Retention and Release from Soilless Substrate

Abstract

<jats:p>A series of column studies were conducted to determine the influence of three different biochar types on nitrate, phosphate, and potassium retention and leaching in a typical greenhouse soilless substrate. A commercial substrate composed of 85 sphagnum peatmoss : 15 perlite (v:v) was amended with 10% by volume of three different biochar types including: gasified rice hull biochar (GRHB), sawdust biochar (SDB), and a bark and wood biochar (BWB). The non-amended control substrate, along with substrates amended with one of three biochar materials, were each packed into three columns. Columns were drenched with nutrient solution and leached to determine the impact of biochar on nutrient retention and leaching. Nitrate release curves were exponential and peaked lower, at later leaching events, and had higher residual nitrate release over time with each biochar amendment. The impact of biochar amendment on phosphate retention and release was more variable within and across the two experiments. In both experiments, the GRHB was a net source of phosphate, providing more phosphate to the system than the fertilizer application and hence obscuring any retention and release effect it might have. Potassium release varied by amendment type within each experiment, but within each amendment type was relatively consistent across the two experiments. All biochar types were a source of potassium, with GRHB providing more than SDB, but both providing far more potassium than the fertilizer event. The BWB amendment resulted in more leached potassium than the control substrate, but relatively little compared with GRHB and SDB amendments.</jats:p>

Microwave vacuum pyrolysis conversion of waste mushroom substrate into biochar for use as growth medium in mushroom cultivation

“…In contrast, BC1:1 had the lowest ash content (15 wt%) because the heat energy generated within the SMS was too low to fully pyrolyze the SMS. Biochar derived from SMS consisted of ash content formed by magnesium (Mg), calcium (Ca), phosphorus (P) and potassium (K) . The high ash content observed in the biochar obtained in this study indicates that the biochar could contain relatively high amount of macro and micronutrient as has been reported by Atland et al ,.…”

“…Biochar derived from SMS consisted of ash content formed by magnesium (Mg), calcium (Ca), phosphorus (P) and potassium (K) . The high ash content observed in the biochar obtained in this study indicates that the biochar could contain relatively high amount of macro and micronutrient as has been reported by Atland et al ,. suggesting that the biochar could be suitable for use in mushroom cultivation because the nutrient contents are important in stimulating the development and formation of mushroom …”

Biochar Type and Ratio as a Peat Additive/Partial Peat Replacement in Growing Media for Cabbage Seedling Production

“…A successful case was mentioned in pot ornamental production growing in paper-waste as a substrate, supported by a hydroponic nutrient solution [29]. Previously, we had addressed the possible explanation for the decreased/low levels in nitrate and in P [30], whereas Altland and Locke [59] reported P release from biochar made from rice husks, with additional studies to be needed to explain the mechanism involved.…”

Organic Growing Media: Constituents and Properties

“…As a consequence of all the above, research into locally available organic and indeed inorganic materials continues apace. Innovative approaches include the use of alternative biomass such as whole pine trees derived from plantation thinning and waste or “slash” from forest residues in the United States (Bilderback et al, 2013; Fields et al, 2014), the manufacture of wood fiber from the oversize fraction of green waste composting in the United Kingdom (Carlile and Waller, 2013), solid digestate from biogas plants (Do and Scherer, 2012; Crippa et al, 2013), and the use of biochar (Altland and Locke, 2013; Zaccheo et al, 2014). Worldwide, much research is focused on the transformation of agricultural, industrial, and municipal wastes (Evans et al, 2011; Raviv, 2013; Moral et al, 2013) into resources that can be used in growing media, with the benefit of diverting wastes from landfills and land spreading, and this approach seems likely in the future to provide large quantities of organic growing media, particularly in arid and semiarid regions of the globe.…”