Conversion of ammonium to nitrate and abundance of ammonium-oxidizing-microorganism in Tropical soils with nitrification inhibitor

Autor(es)

Barth, Gabriel ; Otto, Rafael ; Almeida, Risely Ferraz ; Bran Nogueira Cardoso, Elke Jurandy ; Cantarella, Heitor ; Vitti, Godofredo Cesar

• Tipo de documento: Artigo Científico
• Fonte: CIENTIA AGRICOL; v. 77, n. 4, p. 5-pg., 2020-01-01.

Resumo

The use of nitrification inhibitors (NIs; dicyandiamide - DCD) is an alternative to reduce oxidation of ammonium (NH4+-N) to nitrate (NO3--N) in the soil, reducing NO3--N losses from fertilization practices. Based on the hypothesis that DCD reduces conversion of NH4+-N to NO3--N in tropical soils and inhibits ammonia oxidizing microorganisms (AOM) abundance, soils from the Piracicaba region, Sao Paulo, with different textures (sand, loam and clay) were incubated with ammonium sulphate (AS) and DCD. Contents of NH4+-N, NO3--N, soil pH, and AOM abundance were quantified periodically. Ammonium sulphate increased AOM abundance in all soils, but AS+DCD presented AOM abundances similar to the control. During 90 days of incubation, the effectiveness of DCD in reducing NO3--N production was 1.8, 86.4, and 145.6 mg kg(-1), while the effectiveness of DCD in reducing AOM abundance was 1.2, 3.0 and 2.3 x 10(-3) g soil(-1) for sandy, loamy, and clayey soils, respectively. DCD effectiveness was greater in loamy and clayey soils due to the naturally low nitrification in sandy soils. Application of AS treated with DCD showed potential not only to reduce NO3--N production in loamy and clayey soils, but also to decrease the soil nitrification rate. Overall, DCD was effective in reducing AOM abundance and conversion of NH4+-N to NO3--N in loamy and clay soils evaluated here. The increase in clay content directly influences DCD effectiveness in reducing conversion of NH4+-N to NO3--N. (AU)

• Processo FAPESP: 05/60694-0 - Adubos nitrogenados com inibidores de urease e de nitrificacao na cultura da cana-de-acucar em sistema de colheita sem despalha a fogo.
• Beneficiário: Gabriel Barth
• Modalidade de apoio: Bolsas no Brasil - Doutorado