Forests, Free Full-Text

Por um escritor misterioso

Last updated 27 dezembro 2024

Experiments using 15N–labeled urea were conducted for three years to assess the effect of N-deposition on soil C and N dynamics under oak (Qa) and pine (Pk) forest stands in natural field conditions. Throughout the experiment, an increase in total C, mineral N, and total N due to N deposition was greater in coniferous forest soils than in deciduous forest soils, while decreasing the pH of both soils as a result of nitrification. Natural 13C abundance of soil samples was interpreted to reveal the physical mixing of new C substrates from leaf-litter with old C substrates. The δ13C of the upper soil layers became more negative, with greater decreases in the Pk soil. However, with time, the lowering of δ13C was better maintained in the Pk soil than in the Qa soil, indicating greater incorporation of new C substrates from leaf-litter decomposition into old SOC pools in the Pk soil compared to the Qa soil. We revealed that an increase in total C and N contents due to N deposition was greater under coniferous forest stands than under deciduous forest stands as a result of greater mixing of new C substrates into the soil profile in this temperate forest.