Effect of lime-nitrogen application on N₂O emission from an Andosol vegetable field

Abstract

Lime-nitrogen (calcium cyanamide, CaCN 2 ) is used as a nitrogenous fertilizer, pesticide, and herbicide. During the process of decomposition of lime-nitrogen in the soil, dicyandiamide (DCD), a nitrification inhibitor, is formed. Therefore, lime-nitrogen application may mitigate nitrous oxide (N 2 O) emission from the soil. We conducted a field experiment to investigate the effect of lime-nitrogen on nitrification and N 2 O emission in fertilized soils, and a soil incubation experiment for further analysis of the effect of the limenitrogen. In a field experiment we compared four nitrogen (N) fertilizer treatments: CF (chemical fertilizer), LN100 (application of all N fertilizer as lime-nitrogen), LN50 (application of 50% of N as lime nitrogen and the remainder as chemical fertilizer), and CFD (chemical fertilizer with DCD). In a soil incubation experiment, we also studied two nitrogen treatments: CF and lime-nitrogen. Soil nitrification activity was lower in the LN100, LN50, and CFD plots than in the CF plot. The duration of this reduction in soil nitrification activity was longer in the LN100 plot than in the other plots. We found an apparent decrease in the N 2 O emission rate between 7 and 14 days after fertilization in the LN100, LN50, and CFD plots compared with that in the CF plot. This period of decreased N 2 O emission paralleled that when DCD was detected in the topsoil layers of the former three plots. Moreover, in the soil incubation experiment, cumulative N 2 O emission was significantly lower in the lime-nitrogen treatment than in the CF treatment, although the difference in cumulative N 2 O emission among the plots was not significant in the field experiment. Correlation analysis suggested that application of lime-nitrogen affects N 2 O emission by controlling both the first (ammonium to nitrite) and the second (nitrite to nitrate) soil nitrification reactions, whereas DCD blocks only the first nitrification reaction.

Diurnal pattern of nitrous oxide emissions from soils under different vertical moisture distribution conditions

“…These were much lower than the peak fluxes on 17 June. The high N2O peak emission on 17 June can be attributed to the higher temperature and the faster soil moisture depletion rate, which can increase C and N availability and promote the soil nitrification and denitrification reaction (Kallenbach et al, 2010;Pfab et al, 2012;Yamamoto et al, 2012;Hou et al, 2012). Overall, mean N2O fluxes from the SUW12, SUW15, and SUW18 treatments were 37.4%, 32.7%, and 43.3% lower than those from the SW treatments after two waterings.…”

“…However, a single daily peak in N2O flux variation was observed for all treatments after the second watering. These results suggested that the problem of the diurnal variation curve in N2O emissions was rather complicated, and results were simultaneously affected by multiple factors, such as meteorological factors, soil microorganisms, and soil moisture (Kallenbach et al, 2010;Yamamoto et al, 2012;Trost et al, 2015). For the SW treatment, peaks appeared at 16:00 and 18:00 h on 17 June and 1 July, and at 14:00 h on 22 July (Figures 1d, 1e, and 1f).…”

Lime-nitrogen application reduces N2O emission from a vegetable field with imperfectly-drained sandy clay-loam soil

“…Tokuda (2005) reported that lime-nitrogen application decreased N 2 O emission by 31% to 61% compared with conventional fertilizers in fields with Red-Yellow soils. In addition, we found that lime-nitrogen affected both the first (ammonium to nitrite) and second (nitrite to nitrate) steps of the nitrification process, and lime-nitrogen application decreased N 2 O emission by 1.3% to 13.8% compared to that of conventional fertilizer application in an Andosol field (Yamamoto et al 2012). However, there have been no studies of the effect of lime-nitrogen on N 2 O emission in other soil types.…”

“…Brown et al (2012) reported that nitrification indirectly influenced the process of N 2 O emission by providing a substrate (nitrate, NO 3 − ) for denitrification. We previously reported that lime-nitrogen application inhibited the production of nitrate by controlling nitrification (Yamamoto et al 2012). Therefore, the inhibition of nitrification associated with lime-nitrogen application may indirectly affect N 2 O production derived from denitrification by regulating the supply of a substrate for denitrification.…”

Nitrous Oxide Emissions from Soils with Different Vertical Soil Moisture Distribution Patterns

“…those from SW soil after the first and second waterings, respectively. That is probably because the wetting body and the soil water depleted rate in SUW soils was smaller than in SW soil, which might not easily affect the surface soil microorganisms, soil gas permeability, and other external environmental factors, and slow down the soil microbial activities responsible for GHG emissions [17,23] Generally, N 2 O fluxes from silty clay were in the order of SW>SUW12>SUW15>SUW18 with the fluxes from SW and SUW12 soils being significantly higher than those from SUW15 and SUW18 soils (Table 1), among which the average N 2 O fluxes from SUW15 and SUW18 soils were significantly lower than that from SW and SUW12 soils during the period of 0 to 1,104 h after the first watering, and the average N 2 O flux from SUW12 treatment was significantly lower than those from other treatments 1,506 to 2,370 h after the first watering. However, no significant difference was observed in N 2 O fluxes from the different treatments during the pulse emission period (1,362-1,506 h) after the initial watering.…”