Fluorescence Characteristics of Humic Acid in Chinese Black Soil under Long-Term Fertilization

Table 3

Contributions of characteristic fluorescence parameters to eigenvectors of the first two principal components.

Characteristic parameter	Eigenvector of the first; principal component	Eigenvector of the second; principal component
f450/500	-0.80	0.50
I436/I383	0.70	0.69
I454/I399	0.95	0.09
FLR	-0.98	0.05
HLR	0.98	-0.05
A4/A1	0.86	-0.25
(C2+C3)/C1	0.96	0.15