Seasonal evolution of soil organic matter, glomalin and enzymes and potential for C storage after land abandonment and renaturalization processes in soils of NE Spain

Recently abandoned V and OL soil had small OC contents (mean 2.51 ± 0.25 and 15.26 ± 1.39 g kg− 1) and GRSP (mean 1.04 ± 0.22 and 2.84 ± 0.53 g kg− 1) and large contents of aromatic compounds. By contrast, PR and MB soil had large OC (mean 36.24 ± 0.75 and 37.66 ± 2.38 g kg− 1) and GRSP (mean 4.85 ± 0.87 and 3.88 ± 0.76 g kg− 1) content and smaller contents of aromatic compounds. This suggested a renewal of active OC in older soil. In fact, EE-GRSP and GRSP of more organic soil were positively correlated with the mineralization indices N/O (Furfural/Pyrrole) and O/Y (Pyrrole/Phenol) from active organic compounds (P < 0.05 and P < 0.01 respectively), and negatively correlated (P < 0.05) with the humification index B/E3 (Benzene/Toluene) from recalcitrant organic compounds. Principal component analysis (PCA) identified those environments where soil renaturalization is better. Our findings might indicate the potential for carbon storage in different abandoned shallow soil environments under renaturalization in Mediterranean climate conditions.