Physical, chemical and botanical characteristics of peats used in the horticultural industry.

摘要

The characteristics of peat can be explained by its degree of decomposition (H), dry bulk density (D_BD), air (A_V) and water (W_V) volumes, total pore space (P_S), ash and organic carbon contents, C/N ratio, elemental as well as the botanical composition. This study includes results of 20 horticultural peats obtained from different areas of Estonia, Finland, Germany, Ireland, Latvia, Lithuania and Sweden. The tested peats had a decomposition degree of H3 to H7 and Sphagnum (peat moss) was identified as the major peat forming plant genus (35-90%) followed by Carex (5-50%) and mixture of Eriophorum and woody plant remains (5-20%). The mean D_BD and P_S varied widely from 40 to 141 g L-1 and 87.4 to 96.6% v/v, respectively. Although the tested peats had substantial amounts of W_V (43.3 to 82.1% v/v), their mean water buffering capacities were low (<8% of W_V) to suggest that these peats cannot deliver enough water to the cultivated plant once the easily available water (water held between -1 and -5 kPa; 17.2 to 42.3% v/v) is gone. Mineral contents (NH₄-N, NO₃-N, P, Mg, K, Ca, Mn and Fe) in most peats were considerably low but the computed resource availability indices (C/N, C/P, N/P and N/K) were quite high. The variability of nearly 30 parameters, describing the properties of peat, was examined using a Principal Component Analysis and factors relevant to the first two principal components are discussed in details.