| Name of article: | Odběr vzorků lesních půd podle fixních hloubek – odchylky hodnot chemických vlastností při přepočtu z různých půdních vrstev |
|---|---|
| Number: | 2 |
| Year: | 2022 |
| Author: | Vít Šrámek, Věra Fadrhonsová |
Forest soils can be sampled according to the genetic soil horizons, but in many soil surveys and inventories sampling according the fixed depth intervals is used, which simplifies sampling harmonization as well as statistical evaluation of soil properties. Within the ICP Forests programme the mandatory layers for mineral soil sampling are 0–10 cm, 10–20 cm, 20–40 cm, and 40–80 cm. On the other hand, in some cases – e.g. soil C reporting, the layer of 0–30 cm and 30–100 cm depths are suggested. On the base of more than 100 soil pits sampled by 10 cm depth we try to compare calculated (from 10 cm layer sampling) and estimated (from mandatory ICP Forests layer sampling) soil parameters for the soil depths of 0–30 cm (M03), 30–80 cm (M38) and 30–100 cm (M310). According to the result of Wilcoxon pair test, estimated and calculated values differ for all studied layers except for few individual elements. For practical use, however, calculated and estimated pH values are commutable for M03 and M38 layer as both the relative and absolute differences are negligible. For most soil parameters in these layers the estimated values can be used for evaluation of larger soil survey because the differences in median value are rather small. Caution, however, should be taken when using the estimated values for individual soil pit, where the difference can be substantial. For M310 layers we do not recommend use of estimated soil parameter values because the original data (20–40 cm and 40–80 cm) do not cover the whole soil depth evaluated. This procedure can be tricky especially in cases when the information about the presence of mineral soil below 80 cm depth and its properties (as stoniness) is missing.
