Abstract

NOVOA-MUNOZ, Juan Carlos et al. Prediction of the bulk density of organic horizons in forest soils dominated by Quercus robur in Galicia. Rev. de Ciências Agrárias [online]. 2022, vol.45, n.4, pp.1241-1250.  Epub Dec 01, 2022. ISSN 0871-018X.  https://doi.org/10.19084/rca.28680.

This study searchs for a predictive model for bulk density (ρb) of organic horizons (O) of forest soils dominated by Quercus robur, the main deciduous native specie in the NW of the Iberian Peninsula. Samples of the O horizons (OL and OF+OH; n=96) of 16 stands located in Ordes (Galicia) were collected. In addition to ρb, pH, total contents of organic C and N as well as exchangeable base cations (CBI) were analysed in the samples. Organic horizons were acid (water pH <5,0), with an average organic C >360 g kg-1 and a C/N ratio in the range 21 to 26. The concentration of CBI follows the sequence Ca>Mg>>K>Na. The stepwise multiple linear regression resulted in a model that explains 54% of the ρb variance, being the sum of EBC and total organic C the predictor variables. The Root Mean Squared Error (RMSE) was 0,036 g cm-3 and the coefficient of regresión (R2) between observed and predicted values was 0.65. This predictive model suggests that organic matter quality, rather than its quantity, was more determinant in the estimation of the ρb of organic horizons of forest soils dominated by Q. robur.

Keywords : organic carbon; C/N relationship; pedotransference; nutrients; humification.

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