Potassium Azide as a Nitrification Inhibitor¹

Abstract

The effect of 0, 2, 4, 8, 16, and 32 ppm KN3 on nitrification in soil was studied at 30 and 10 C. At both temperatures, KN3 was an effective nitrification inhibitor. At 30 C, 75 ppm of added NH4 + disappeared in 2 weeks where no KN3 had been added as compared to 4 weeks at the 32 ppm KN3 rate. At 10 C, 4 weeks were required for the NH4+ to disappear at 0 ppm KN3, whereas more NH4+ was present after 18 weeks than initially where 32 ppm KN3 was applied. Concentrations of (NO2‐ + NO3‐)‐ N were found to be similar at all KN3 rates once the NH4+ had disappeared. This indicates that KN3 had no effect on mineralization‐immobilization relationships. The soil pH for both incubation temperatures was 6.8. The effect of 4 ppm KN3 in soil incubated at 30 C was studied at soil pH levels of 4.5, 6.0, and 7.5. The NH4‐N and (NO2‐ + NO3‐)‐N concentrations during 4 weeks incubation indicated that KN3 did not inhibit nitrification at soil pH levels of 4.5 and 6.0 but that nitrification was inhibited at pH 7.5. At 30 C, KN3 does not appear to be an effective nitrification inhibitor for soils of pH less than 6.0.

Organic matter fractions and N mineralization in vegetable‐cropped sandy soils

“…Nitrification inhibitors are compounds that delay bacterial oxidation of NH 4 + by depressing activities of soil nitrifying bacteria. In theory, reducing nitrification under conditions where there is a high risk of N loss from NO 3 -leaching or denitrification, should improve N-use efficiency (NUE) (Hughes and Welch, 1970). But several limitations or constraints have affected the widespread adoption of chemical nitrification inhibitors.…”

A quantitative evaluation of the comparative value of six fertilizer–nitrogen sources for potatoes

“…Ammoniacal sources are per se liable to losses through mechanisms (ii-v), whereas nitrate sources are acted upon by the first two processes only. Under the semi-tropical Indian soil conditions, it is unlikely that NH 4 +-N could persist in the soil in an available form even through a single potato crop season, unless nitrification inhibitors, such as 'N-serve' (Goring, 1962) or potassium azide (Hughes & Welch, 1970) are used simultaneously with the ammoniacal fertilizers. The NO 3~ formed is easily leached down well below the root zone through the irrigation applied to the normally welldrained potato soils.…”

Effects of urease inhibitors, nitrification inhibitors and pesticides on denitrification in soil

“…Source^ Reference ^ 1, Bundy and Bremner (1973b); 2, Goring (1962a); 3, Goring (1962b); 4, Hauck (1972); 5, Hughes and Welch (1970);6, Parr et al (1971); 7, Malzer (1979); 8, Rodgers et al (1983); 9, Sommer (1972); 10, Varsa and Ruber (1983);11, Ashworth et al (1980); 12, Hooper and Terry (1973); 13, Lees (1952); 14, Frankenberger and Tabatabai (1982);15, Heytler et al (1984); 16, Lodhi (1982); 17, Rice and Pancholy (1974); 18, Rice and Pancholy (1973);19, Ashworth et al (1977); 20, Henninger and Bollag, (1976); 21, Reddy (1964).…”