Chemical and Biological Technologies in Agriculture

Table 1 Calculations from optical measurements of each sample

From: Characterization of terrestrial dissolved organic matter fractionated by pH and polarity and their biological effects on plant growth

Sample	SUVA254	FI	EEMs Peak Areas
Sample	(L mg ⁻¹ m ⁻¹ )	FI	% A	% C	% T
Whole	8.35	1.34	61%	37%	2%
Acid insoluble	8.00	1.13	62%	35%	3%
Acid soluble	6.50	1.40	59%	39%	2%
C18 filtrate	5.16	1.44	56%	41%	2%
C18 retentate	6.53	1.29	61%	36%	3%

SUVA254: specific ultraviolet absorbance at 254 nm.
FI: fluorescence index, emission ratio of 420:520 nm at excitation 370 nm.
Peak A: 240–300 nm Ex; 400–500 nm Em.
Peak C: 300–360 nm Ex; 400–500 nm Em.
Peak T: 240–300 nm Ex; 250–350 nm Em.
Absorbance and EEMs fluorescence spectra are shown in Figure 2.

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