Efficacy of the Nitrification Inhibitor 3,4 Dimethylpyrazol Succinic Acid (DMPSA) when Combined with Calcium Ammonium Nitrate and Ammonium Sulphate—A Soil Incubation Experiment

• Main Authors: Niharika Rahman, Catarina Henke, Patrick J. Forrestal
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Agronomy
• Subjects: nitrogen fertiliser; ammonium; nitrate; nitrification inhibitor; incubation; soil texture
• Online Access: https://www.mdpi.com/2073-4395/11/7/1334
• ISSN: 2073-4395

The efficacy of the new nitrification inhibitor 3,4 dimethylpyrazol succinic acid (DMPSA) was tested with calcium ammonium nitrate (CAN) and ammonium sulphate (AS) fertilisers in an incubation experiment using a sandy loam soil and a sandy textured soil. The experiment was conducted over 80 days. For AS fertiliser, inclusion of DMPSA resulted in significantly less NO₃⁻-N present after 19 days in both soils. In the case of CAN, inclusion of DMPSA resulted in significantly less NO₃⁻-N present after 45 days in the sandy loam soil and after 30 days in the sandy soil. DMPSA is effective nitrification inhibitor when combined with CAN and AS, with a mean reduction of 61% and 58%, respectively, in the average daily nitrification rate over the study period. Over the 80-day incubation period in the sandy loam soil, only 35% NH₄⁺-N was converted to NO₃⁻-N for AS + DMPSA compared to 88% for AS. In the sandy soil, 92% NH₄⁺-N was converted to NO₃⁻-N for AS compared with only 9% for AS + DMPSA by day 80. The results demonstrate that DMPSA is an effective nitrification inhibitor when combined with CAN and AS.