Effects of different forms of plant-derived organic matter on nitrous oxide emissions

Abstract

To investigate the impact of different forms of plant-derived organic matter on nitrous oxide (N2O) emissions, an incubation experiment with the same rate of total nitrogen (N) application was carried out at 25 °C for 250 days. Soils were incorporated with maize-derived organic matter (i.e., maize residue-derived dissolved organic matter and maize residues with different C/N ratios) and an inorganic N fertilizer (urea). The pattern and magnitude of nitrous oxide (N2O) emissions were affected by the form of N applied. Single application of maize-derived organic matter resulted in a higher N2O emission than single application of the inorganic N fertilizer or combined application of the inorganic N fertilizer and maize-derived organic matter. The positive effect of maize residue-derived dissolved organic matter (DOM) addition on N2O emissions was relatively short-lived and mainly occurred at the early stage following DOM addition. In contrast, the positive effect induced by maize residue addition was more pronounced and lasted for a longer period. Single application of maize residues resulted in a substantial decrease in soil nitric nitrogen (NO3(-)-N), but it did not affect the production of N2O. No significant relationship between N2O emission and NO3(-)-N and ammonium nitrogen (NH4(+)-N) suggested that the availability of soil N was not limiting the production of N2O in our study. The key factors affecting soil N2O emission were the soil dissolved organic carbon (DOC) content and metabolism quotient (qCO2). Both of them could explain 87% of the variation in cumulative N2O emission. The C/N ratio of maize-derived organic matter was a poor predictor of N2O emission when the soil was not limited by easily available C and the available N content met the microbial N demands for nitrification and denitrification. The results suggested that the magnitude of N2O emission was determined by the impact of organic amendments on soil C availability and microbial activity rather than on soil N availability. In agricultural management practices, if the N inputs from organic and inorganic N fertilizers are equivalent, addition of organic N fertilizers that contain high amounts of available C will result in a higher N2O emission.

Potential Production of CH4 And N2O in Soil Profiles from Organic and Conventional Rice Fields

“…Available Online at SAINS TANAH Website : http://jurnal.uns.ac.id/tanah/index SAINS TANAH -Journal of Soil Science and Agroclimatology, 15(1), 2018, 54- Potential production of N2O correlated positively with total organic carbon (TOC) (r=0.87, P<0.001, n=8), humic acid (HA) (r=0.85, P<0.001, n=8), fulvic acid (FA) (r=0.82, P<0.001, n=8) and total nitrogen (TN) (r=0.94,P<0.001,n=8). This result was supported by finding of Qiu, Q., L. Wu, Z. Ouyang (2016) who stated that addition of N-organic fertilizer causes higher N2O emissions than the application of single N-inorganic fertilizer or together with Norganic fertilizers. According to Huang, et al (2004) application of organic matter produced higher N2O emissions than urea.…”

Can Incorporating Brassica Tissues into Soil Reduce Nitrification Rates and Nitrous Oxide Emissions?

“…In contrast, other studies have found relationships between CO 2 and N 2 O emissions (Millar and Baggs, 2004) or between N 2 O production and the C/N ratio of plant material being incorporated, with generally higher emissions from plants with low C/N ratios (Kaiser et al, 1998; Baggs et al, 2000). Qiu et al (2016), however, suggested that the C/N ratio was not a good predictor of N 2 O emissions if available soil N was not limited, as was the case in the current study with the addition of urea.…”

“…We were able to distinguish N 2 O emissions derived from urea N and those derived from added plant N by calculating the difference between emissions from the combined urea and plant treatment (ryegrass 600N, kale 600N, turnip leaf 600N, and turnip bulb 600N) and the plant‐only treatment (ryegrass 0N, kale 0N, turnip leaf 0N, and turnip bulb 0N). The addition of plants, without urea, also increased N 2 O emissions, presumably because increased labile C and N from plant cells provided substrate for nitrification and denitrification (Reddy et al, 1982; Baggs et al, 2000; Kuzyakov and Bol, 2006; Qiu et al, 2016). However, this addition of C alone does not explain the significant difference in emissions between the ryegrass treatment and other tissue treatments, as roughly similar C was added for all plant treatments.…”

Evaluation of antibacterial and antifungal compounds for selective inhibition of denitrification in soils

“…1,2 As denitrifying microbes are largely heterotrophs, N2O production is often limited by the availability of metabolizable organic carbon. 3 Both fungi and bacteria participate in N2O production in soils 18 , and therefore their relative contribution to the denitrification process can be affected by land-use and management. Among anthropogenic activities, agriculture has been identified as the largest contributor to global N2O emission, largely due to tillage operations and application of N fertilizers.…”