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Abstract

In agricultural soils, the carbon stocks are affected by changes in land-use systems or management practices. When silvopastoral systems are converted to arable lands, an effective decrease in soil carbon stocks, mainly in upper soil layers is expected. The aim of this work was to evaluate total C and N stocks in soil after conversion of silvopastoral systems to different land-use systems. The study areas are located in northeast Germany and refer to different land-use systems comprising: 2 areas after 4 years of conversion from silvopasture to arable land (SP-AR) and grassland (SP424 GL); and 2 areas cultivated for more than 30 years under continuous arable land (C-AR) and silvopasture with apple trees and grass (C-SP). Carbon and nitrogen stocks were evaluated at 2 different depths (0 10 and 10 20 cm). Total carbon stocks ranged from 8.6 16.1 Mg ha-1 at 0 10 cm and from 7.7 13.4 Mg ha-1 at 10 20 cm depth. Soils under continuous arable land presented the lowest C stocks in the upper layer. After 4 years of conversion from silvopastoral system into arable land and grassland, total stocks of C and N had values similar to silvopasture when the 0 20 cm depth was considered. Carbon stocks declined by 47% from the 0 10 to the 10 20 cm layer in treatments where soil was not revolved (C-SP and SP-GL). Total nitrogen followed the same trend as carbon, with the lowest value at C-AR study site (0.87 Mg ha-1 at 0 10 cm). Except for C-AR, the C/N ratio was similar (around 12.5±0.2) for all land-use systems at 0 10 cm depth. Land-use conversion from silvopastoral systems in arable land led to a decline in the stocks of C and N in the upper layer.