Relationship between tillage management and DMPSA nitrification inhibitor efficiency

摘要

Agricultural sustainability is compromised by nitrogen (N) losses caused by soil microbial activity. Nitrous oxide (N_2O) is a potent greenhouse gas (GHG) produced as consequence of nitrification and den-itrification processes in soils. Nitrification inhibitors (NI) as 3,4-dimethylpyrazole-succinicacid (DMPSA) are useful tools to reduce these N losses from fertilization. The objective of this work was to test the efficiency of DMPSA in two different tillage management systems, conventional tillage (CT) and no-tillage (NT), in a winter wheat crop under Humid Mediterranean conditions. N fertilizer was applied as ammonium sulphate (AS) with or without DMPSA in a single or split application, including an unfertilized treatment. GHG fluxes (N_2O, CO_2 and CH_4) were measured by the closed chamber method. amoA and nosZl genes were quantified by qPCR as indicators of nitrifying and denitrifying populations. Nitrification was inhibited by DMPSA in both CT and NT, while the higher water filled pore space (WFPS) in NT promoted a better efficiency of DMPSA in this system. This higher efficiency might be due to a greater N_2O reduction to N_2 as result of the nosZl gene induction. Consequently, DMPSA was able to reduce N_2O emissions down to the unfertilized levels in NT. Provided that NT reduced CO_2 emissions and maintained crop yield compared to CT, the application DMPSA under NT management is a promising strategy to increase agro-systems sustainability under Humid Mediterranean conditions.