TABLE 1.

LIC₅₀s and AIC₅₀s^a of several nitrification inhibitors

Inhibitor	LIC50 (μM) with an incubation time of:		AIC50 (μM)b
	1 min	5 min
Allylsulfide	1.8	1.3	9.2
Allylthiourea	0.54	0.15	0.06
Dicyandiamide	9,790	3,840	4,530
2,4-Dinitrophenol	71.2	62.6	539
Formaldehyde	1,680	1,110	1,750
HgCl2	2.7	2.1	1.7
Methanol	4,440	3,230	32,600
NaN3	2,330	460	562
Na2Sc	47.5	10.3	67.1
Nitrapyrin	4.1	0.74	0.76
Pentachlorophenol	13.7	10.6	45.5
Phenol	19.8	18.0	10.4
Picolinic acid	199	91	11.9
8-Quinolinol	2.0	1.7	2.1
Thioacetamide	0.41	0.04	0.09
Thiosemicarbazided	3.6	0.9	0.4

^aLIC₅₀s and AIC₅₀s were calculated from graphed data of dose-response experiments as shown in Fig. 4. 

^bDetermined after 30 min of incubation. 

^cNa₂S · 9H₂O was used. 

^dThiosemicarbazide hydrochloride was used.