Effect of Composting on Dissolved Organic Matter in Animal Manure and Its Binding with Cu

Table 1

Fitting parameters of Ryan-Weber model.

DOM samples^a	Ex/Em (nm)^b	𝐼Cu𝐿 (AU)^b	CCCu (mmol/g)^b	log𝐾^bCu	DC^b
A1	276/306	260.98	50.60	5.24	0.992**
A71	315/412	79.04	1.99	5.14	0.998**
B1	276/306	296.51	55.00	5.17	0.987**
B71	315/412	91.00	0.41	5.02	0.996**
C1	305/412	39.90	6.52	4.90	0.997**
C46	310/408	46.48	0.53	5.08	0.998**
D1	310/414	81.69	7.78	4.93	0.996**
D46	310/420	53.71	1.62	5.00	0.998**

^aDOM from treatment A (pig manure + sawdust) on days 1 and 71 (A1, A71), treatment B (pig manure + corn stalk) on days 1 and 71 (B1, B71), treatment C (cattle manure + sawdust) on days 1 and 46 (C1, C46), and treatment D (cattle manure + corn stalk) on days 1 and 46 (D1, D46).
^bEx/Em: selected wavelengths for the fluorescence titration; 𝐼_Cu𝐿: fluorescence intensity of Cu ion-saturated complex (arbitrary units: AU); CC_Cu: complexing capacity (mmol/g); log 𝐾_Cu: the conditional stability constant; DC: determinative coefficiency.
**Statistical significance value 𝑃<0.001.