Changes in Soluble-N in Forest and Pasture Soils after Repeated Applications of Tannins and Related Phenolic Compounds

Table 2

Details about treatment compounds [34].

Treatment			Compound characteristics					Solution characteristics^¶
	Class	Source	MW^†	C^‡; (%)	N^‡; (%)	C; (g mol^−1)	Kow^§	Soluble-C; (mg kg^−1 soil)	Soluble-N; (mg kg^−1 soil)	Phenolics^#; (mmol GA equiv kg^−1 soil)	pH; (1mg/mL)
Methyl 3,4,5-trihydroxybenzoate, 98% (methyl gallate)(MG)	Phenolic organic ester	Indofine Chemical Co., Hillsborough, NJ	184	51.7	0.084	96	6.3	5141	0.1	37.2	4.4
Gallic acid, certified (GA)	Phenolic organic acid	Fisher Scientific,Pittsburgh, PA	170	47.7	0.106	85	0.3	4739	0	52.6	3.3
Tannic acid, certified (TA)	Mixture of gallotannins	Fisher Scientific, Pittsburgh, PA	902	49.4	0.142	474	ND	5042	2.5	30.7	3.5
β-1,2,3,4,6 penta-O-galloyl-D-glucose (PGG)	Gallotannin	Purified fromTannic Acid (Fisher)	941	49.7	0.099	492	129	5037	0.7	26.1	5.1
(+)-Catechin hydrate, >98% (CAT)	Flavonoid	Sigma, St Louis, MO	290	61.6	0	180	2.4	6067	1.0	32.1	5.6
[(4β- >8)-epicatechin15-(4β- >8)-catechin] (Sorghum procyanidin) (SOR)	Polymeric flavonoid	[Sorghum bicolor (L.) Moench]	4624	48.6	0.094	2880	0.002	5189	8.2	13.7	6.0

^†Number average molecular weight for TA estimated by RP-HPLC by Hagerman (Personal Communication) and used to calculate weighed average g C mol⁻¹.
^‡Total C and N were determined in triplicate with a FlashEA 1112 NC Analyzer (CE Elantech, Lakewood, NJ).
^§Octanol-water partition coefficients (K_ow) for PGG CAT and SOR from [45] GA and MG from Lu et al. [46]. Low values correspond to hydrophilic compounds while higher values are indicative of hydrophobic ones.
^¶Supplied g⁻¹ soil application⁻¹.
^#Determined by the Modified Prussian Blue assay.