Organic carbon, organic matter and bulk density relationships in boreal forest soils

Abstract

Pe´rie´, C. and Ouimet, R. 2008. Organic carbon, organic matter and bulk density relationships in boreal forest soils. Can. J. Soil Sci. 88: 315Á325. Relationships between soil organic carbon (SOC), organic matter (SOM), and bulk density (BD) were established in acidic loamy to sandy loam fine fractions of forest soils in Quebec (Canada). The interest of such relationships rests with the possibility of using simple and rapid techniques to estimate SOC and BD. It is also a crucial step in establishing the correspondence among several data bases when SOC data are obtained using different measurement techniques. In this study, SOC was measured by dry combustion (SOC DC ) and wet digestion (SOC WD ) methods, and organic matter by loss-on-ignition (LOI). Our results suggest that, in these soils: (1) LOI can be used for estimating SOC (r 2 00.95, RMSEP 016%) and SOC DC /SOM significantly decreased with increasing depth from 0.49 to 0.27; (2) SOC DC and SOC WD were highly correlated. Even if SOC WD provided near complete recovery of SOC DC , dry combustion remains the preferred method for SOC analysis since SOC WD recovery decreased with increasing depth from 100 to 83%. (3) BD was also strongly related to SOM (r 2 00.81). We recommend using the organic density approach to estimate BD from SOM because it allows BD to be predicted without significant bias and with a degree of accuracy of 14%.Key words: Forest soils, soil organic carbon, soil organic matter, soil bulk density Pe´rie´, C. et Ouimet, R. 2008. Liens entre le carbone organique, la matie`re organique et la masse volumique apparente dans le sol des foreˆts bore´ales. Can. J. Soil Sci. 88: 315Á325. Les auteurs ont pre´cise´les liens entre le carbone organique (COS), la matie`re organique (MOS) et la masse volumique apparente (MVA) du sol dans les fractions fines de loam et de loam sablonneux des sols forestiers acides du Que´bec. De tels liens pre´sentent un certain inte´reˆt, car on pourrait y recourir comme technique simple et rapide pour e´valuer la concentration de COS et la MVA. Il s'agit aussi d'une e´tape cruciale quand on souhaite e´tablir une correspondance entre des bases de donne´es ou`la concentration de COS e´mane de diverses techniques. Dans le cadre de la pre´sente e´tude, la quantite´de COS a e´te´de´termine´e par combustion se`che (COS CS ) et digestion par voie humide (COS DH ) tandis qu'on a mesure´la concentration de matie`re organique au moyen des pertes par calcination (PPC). Les auteurs ont obtenu les re´sultats que voici pour les sols concerne´s. (1) La me´thode PPC permet d'estimer le COS (r 2 0 0,95, RMSEP 0 16 %) et le ratio COS CS /MOS diminue de manie`re significative, de 0,49 a`0,27, avec la profondeur. (2) Il existe une importante corre´lation entre le COS CD et le COS DH . Bien que la technique COS DH permette de re´cupe´rer la quasi totalite´du COS CS , la combustion se`che demeure la me´thode privile´gie´e pour analyser le COS, la quantite´de carbone re´cupe´re´e par COS DH passant de 100 a`83 % a`mesure qu'augmente la profond...

Seasonality of soil water exchange in the soybean growing season in southern Brazil

“…The total porosity was greater under NT at the surface layer, attributable to its high microporosity. The ρb on the surface (0.05 m) was equal under both systems, possibly influenced by soil biological activity, activities of roots, and greater presence of organic matter (Périé and Ouimet, 2008;Boddey et al, 2010).…”

Disturbance Legacy on Soil Carbon Stocks and Stability within a Coastal Temperate Forest of Southwestern British Columbia, Canada

“…Périé and Ouimet (2008) recommended using the organic density approach to estimate BD from SOM because it allows BD to be predicted without significant bias and with a degree of accuracy of 14%. The values for D bm and D bo were also chosen by Grand and Lavkulich (2011) for Humo-Ferric Podzol evaluations on glacial till on the Sunshine Coast of southwestern British Columbia and are in good agreement with other studies conducted in medium to coarse-textured acid forest soils (Federer et al, 1993).…”

“…Thus, values for BD were also estimated using pedotransfer functions as suggested by Grand and Lavkulich (2011). The pedotransfer functions are based on the correlation between BD and SOC (or SOM) concentration in soil horizons (Heuscher et al, 2005;Périé & Ouimet, 2008). For BD of mineral soil horizons, we used the empirical regression (Equation (1)) developed by Heuscher et al (2005) for the Orthod Spodosol great group (Humo-Ferric Podzols).…”

“…We used the empirically determined D bm = 1.77 ± 0.07 and D bo = 0.11 ± 0.01 by the nonlinear model (r 2 = 0.81) of Périé and Ouimet (2008), who have established the relationship between SOM concentration and BD in acidic loamy to sandy loam fine fractions of forest soils in Quebec (Canada). SOC content of each soil horizon was calculated based on estimated BD values (g•cm −3 ) (Equation (1) for < 2 mm mineral soil or Equation (2) for organic layer), the relative contribution of fine fraction to total soil mass (FE content in g•g −1 ), horizon thickness (cm), SOC concentration (g•kg −1 ) and a unit-conversion factor (100) (Equa-…”

Effects of Restoration Techniques on Soil Carbon and Nitrogen Dynamics in Florida Longleaf Pine (Pinus palustris) Sandhill Forests

“…A factor of conversion is often used to compensate for the incomplete oxidation of organic C, but the use of this factor has the potential for serious error when estimating the C content of soils. Indeed, this factor of conversion, which is quite variable (1.35 to 14.1; [54]), has been shown to vary with soil type, mineralogy and soil depth [55,56]. Similarly, dry combustion processes have also resulted in greater N values than the Kjeldahl method [57,58].…”