Denitrification and Nitrate Consumption in an Herbaceous Riparian Area and Perennial Ryegrass Seed Cropping System

Abstract

Davis et al. (2006) found that <1.2% of applied 15 NO 3 − ended up in the microbial biomass of an herbaceous riparian zone, 2 mo after application. Yin et al. (2002), however,

Denitrification and Nitrous Oxide Emissions in Annual Croplands, Perennial Grass Buffers, and Restored Perennial Grasslands

“…These results are consistent with higher DEA in riparian buffers compared with crop fields (Groffman et al, 1993;Kim, 2008). Consistent with previous work (Davis et al, 2008), we also observed a positive correlation between TOC and DEA as well as NH 4 + -N and DEA. The positive relationship between NH 4 + -N and DEA could be due to (i) NH 4 + -N regulation of NO 3 − -N consumption and production (Davis et al, 2008) or (ii) it can be an indirect relationship resulting positive correlations among TOC, NH 4 + -N, potentially mineralizable C, and N mineralization (Schomberg et al, 2009;Haddad et al, 2013).…”

“…Consistent with previous work (Davis et al, 2008), we also observed a positive correlation between TOC and DEA as well as NH 4 + -N and DEA. The positive relationship between NH 4 + -N and DEA could be due to (i) NH 4 + -N regulation of NO 3 − -N consumption and production (Davis et al, 2008) or (ii) it can be an indirect relationship resulting positive correlations among TOC, NH 4 + -N, potentially mineralizable C, and N mineralization (Schomberg et al, 2009;Haddad et al, 2013). Opposite patterns of in situ N 2 O fluxes and DEA across the watershed treatments led us to pursue denitrification measurements.…”

Assessment of the importance of dissimilatory nitrate reduction to ammonium for the terrestrial nitrogen cycle

“…Under anaerobic conditions, sulphide stimulates DNRA, by serving as an electron donor, and depresses denitrification, by repressing NO and N 2 O reductase (Myers, 1972;Brunet and Garcia-Gill, 1996). In this line DeCatanzaro et al (1987) found in the above mentioned study a stimulation of DNRA when simultaneously adding glucose and sulphide, which contrasted the finding from only glucose addition.…”

“…Chen et al (1995) identified several possible explanations, including the high native soil C content compared to the amount of added glucose, unfavourable redox conditions for DNRA or effects of soil rewetting. DeCatanzaro et al (1987) also did not find an effect of glucose addition on DNRA, but revealed that DNRA was stimulated by alfalfa addition. This was apparently an effect of sulphur in alfalfa, which was released as -SH group during sulphur mineralisation of organic matter and served as reducing agent.…”

“…Other C sources, like straw, glycerol, methanol and succinate did not promote DNRA (Buresh and Patrick, 1978;deCatanzaro et al, 1987;Yin et al, 1998). The reasons for this are not fully understood and deserve further investigations.…”