Effect of 26 Years of Intensively Managed Carya cathayensis Stands on Soil Organic Carbon and Fertility

Table 4

Distributions of different chemical shift ranges in total signal intensity (%) for ¹³C NMR in organic carbon of A horizon soil under a C. cathayensis forest stand sampled in 1982 and 2008.

Year	Alkyl C (%)	O-alkyl C (%)	Aromatic C (%)	Carbonyl C (%)	A/O-A	Aromaticity (%)
1982	29.93^a	46.41^a	12.82^a	10.83^b	0.64	14.38^b
2008	20.83^b	49.19^a	15.97^a	14.00^a	0.42	18.57^a

Note: the dissimilar letters in the same column indicate significant difference at 𝑃<0.05 level.