Effects of olive mill wastewater and two natural extracts as inhibitors of nitrifying bacteria activity and Nitrate Leaching Loss. tests on pot culture of celery (Apium graveolens L.). (L'Accademia per il post Covid-19.)

ABSTRACT

Effects of Olive Mill Wastewater and Two Natural Extracts as Nitrification Inhibitors on Activity of Nitrifying Bacteria, Soil Nitrate Leaching Loss, and Nitrogen Metabolism of Celery (Apium graveolens L.). Minimizing nitrification of fertilizer ammonium (NH4 +) can reduce nitrate (NO3 -) contamination of groundwater and increase nitrogen (N) use efficiency (NUE). Olive mill wastewater (OMW), hydroalcoholic extracts of Mentha piperita L.(Mp) and Artemisia annua L.(Aa), and the synthetic nitrification inhibitor (NI) dicyandiamide (DCD) were investigated. The three natural products and DCD reduced activity of nitrifying bacteria and decreased NO3 - leached, compared to the untreated control. OMW proved to be an almost equally effective natural alternative to DCD as a NI.