Abstract
Soil carbon sequestration is strongly affected by soil properties, climate, and anthropogenic activities. Assessing these drivers is key to understanding the effect of land use on soil organic matter stabilization. We evaluated land use and soil depth influencing patterns of soil organic matter stabilization in three types of soil profiles located under the same pedogenetic matrix and alpine conditions but with different vegetation cover. The stock in soil organic carbon in the mean 0–20 cm layer increased from prairie (31.9 t ha−1) to prairie in natural reforestation (42 t ha−1) to forest (120 t ha−1), corresponding to increments of 1.3-fold prairie, for prairie in natural reforestation, and of 3.8-fold prairie for forest. The forest showed the highest humic carbon (21.7 g kg−1), which was 2.8 times greater than the prairie in natural reforestation and 4 times higher than the prairie. 13C-NMR spectroscopic measurements suggested a different C pattern. The prairie in natural reforestation and the prairie were characterized by a higher content in O,N-alkyl C with respect to the forest. Alkyl C and aromatic C in the prairie in natural reforestation and prairie did not show relevant differences while they decreased with respect to the forest. Carboxyl and phenolic C groups were markedly higher in forest and prairie than prairie in natural reforestation. Alkyl C, carboxyl C, and phenolic C prevailed in the Ah horizons whereas aromatic C and O,N-alkyl C were dominant in the B horizons. Overall, the marked distribution of O,N-alkyl C and alkyl C in humic substances (HS) indicates a low degree of humification. Nevertheless, in forest, the relatively high presence of aromatic C designated HS endowed with a relatively high humification degree. Thus, our results might suggest that in the alpine environment of NE Italy differences in soil organic matter (SOM) stocks and characteristics are affected by land use and anthropic activities.
Highlights
Forests play an important role in the global carbon (C) cycle by capturing CO2 from the atmosphere, converting it into biomass, and emitting it back into the atmosphere or fixing it into stable soil organic matter pools [1]
What appeared appeared related related to to the the nature nature of of the the parent parent layer layer is isthe thethixotropy, thixotropy, aa property property layer that was was developed in quasi in that developed in quasi all all horizons horizons showing showing aa sub-angular sub‐angular blocky blocky structure
Stand age and site physical and topographic variables are known to affect soil carbon content and characteristics [6,9], but this study showed that the alpine forest carries a large amount of organic carbon and humic carbon, which is respected both at reforestation and prairie
Summary
Forests play an important role in the global carbon (C) cycle by capturing CO2 from the atmosphere, converting it into biomass, and emitting it back into the atmosphere or fixing it into stable soil organic matter pools [1]. C storage in soil ecosystems can be affected by stand management practices and land use [12,13]. Land management plays an important role as source and/or sink of C [15]. Soil organic C (SOC) stock can be modified by land use because of different inputs of organic matter, different canopy structures, as well as different physical and chemical properties of soil. There is a considerable amount of evidence showing that forests converted to cultivated cropland decreased their organic layer, soil C content, and cation exchange capacities [16]. In a study by Li et al, [17] over 30 years, the SOC storage did not decrease significantly after a land use change from primary rain forest to fallow land, it did increase significantly (49.3%) due to conversions to natural secondary forest and rubber plantations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
