The mechanisms of increase in NH3 emission with NI have been explained as follows:
First, NH4+ retains longer in soil owing to NI and may increase NH3 emission (e.g., Asing et al., 2008; Zaman et al., 2009).
Second, the DCD-induced reduction in nitrification would reduce soil acidification resulting in a prolongation of the elevated pH and a consequent increase in NH3 emission losses (Fox and Bandel, 1989).
Third, by maintaining the NH4+ in the soils, it caused a priming effect with a subsequent increase in the rate of soil organic matter mineralization and an extra release of soil organic N (Gioacchini et al., 2002).
The concern of increased NH3 emission by NI treatments appeared in literature from late 1960 (Hauck and Bremner, 1969) and it was argued that NI use may trade-off for mitigating N2O to increasing NH3 emissions (Mkhabela et al., 2006) that are indirect source of N2O (e.g., Martikainen, 1985) and cause soil acidification (e.g., Van der Eerden et al., 1998; Rennenberg and Gessler, 1999) and eutrophication (e.g., Bobbink et al., 1992).
In contrast, a few studies showed no significant increase in NH3 emission after NI treatments in field experiments (Clay et al., 1990) and lab incubation experiments (e.g., Clay et al., 1990; Dendooven et al., 1998; Mkhabela et al., 2006).
In contrast, a few studies showed no significant increase in NH3 emission after NI treatments in field experiments (Clay et al., 1990) and lab incubation experiments (e.g., Clay et al., 1990; Dendooven et al., 1998; Mkhabela et al., 2006).
Nice work, Dong-Gill Kim! There are lots of things to learn about nitrification. The definition and the basic process are not enough. Everyone should know the effects and the other "back-end" stuff about it. Source: http://nitrification.org
ReplyDeleteMenendez, S., Merino, P., Pinto, M., Gonzalez-Murua, C., Estavillo, J.M., 2006. 3,4-dimethylpyrazol Phosphate Effect On Nitrous Oxide, Nitric Oxide, Ammonia, And Carbon Dioxide Emissions From Grasslands. J. Environ. Qual. 35, 973-981
ReplyDeleteIntensively managed grasslands are potentially a large source of NH3, N2O, and NO emissions because of the large input of nitrogen (N) in fertilizers. Addition of nitrification inhibitors (NI) to fertilizers maintains soil N in ammonium form. Consequently, N2O and NO losses are less likely to occur and the potential for N utilization is increased, and NH3 volatilization may be increased. In the present study, we evaluated the effectiveness of the nitrification inhibitor 3,4-dimethylpyrazol phosphate (DMPP) on NH3, N2O, NO, and CO2 emissions following the application of 97 kg N ha−1 as ammonium sulfate nitrate (ASN) and 97 kg NH4 +–N ha−1 as cattle slurry to a mixed clover–ryegrass sward in the Basque Country (northern Spain). After slurry application, 16.0 and 0.7% of the NH4 +–N applied was lost in the form of N2O and NO, respectively. The application of DMPP induced a decrease of 29 and 25% in N2O and NO emissions, respectively. After ASN application 4.6 and 2.8% of the N applied was lost as N2O and NO, respectively. The application of DMPP with ASN (as ENTEC 26; COMPO, Münster, Germany) unexpectedly did not significantly reduce N2O emissions, but induced a decrease of 44% in NO emissions. The amount of NH4 +–N lost in the form of NH3 following slurry and slurry + DMPP applications was 7.8 and 11.0%, respectively, the increase induced by DMPP not being statistically significant. Levels of CO2 emissions were unaffected in all cases by the use of DMPP. We conclude that DMPP is an efficient nitrification inhibitor to be used to reduce N2O and NO emissions from grasslands.
Menendez, S., Estavillo, J., Gonzalez-Murua, C., Pinto, M., Merino, P., 2009. Effect of N-(-butyl) Thiophosphoric Triamide and 3, 4 Dimethylpyrazole Phosphate on Gaseous Emissions from Grasslands under Different Soil Water Contents. Journal of Environmental Quality 38, 27-35
ReplyDeleteThe intensification of grassland systems is leading to serious environmental risks due to the large input of nitrogen (N) in fertilizers and the subsequent gaseous losses. Addition of nitrification inhibitors (NI) or urease activity inhibitors to fertilizers could reduce these losses to the atmosphere. In the present study, the effects of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) and the urease activity inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) were evaluated on NH3, N2O, NO, and CO2 emissions. Ammonium sulphate nitrate (ASN), urea and cattle slurry were applied at a rate of 70 kg N ha−1 to a mixed clover-ryegrass sward in the Basque Country (northern Spain) under different soil water contents. NH3 and NO emissions were determined by photoacoustic and chemiluminescence respectively using an open chamber technique while N2O and CO2 emissions were measured by photoacoustic using a closed chamber technique. When the water filled pore space (WFPS) was under 60%, the application of NBPT reduced NO emissions a 34% on urea and an 18% on slurry, and the application of DMPP reduced them a 2% on ASN and a 4% on slurry. No significant effect was observed on NH3 losses. When WFPS was over 60%, no effect could be observed on NO and N2O emissions after the application of both inhibitors, but NH3 losses were reduced a 31% by NBPT when applied with the slurry. Carbon dioxide emissions were unaffected by the use of DMPP or NBPT at any soil water content. Neither grassland yield nor herbage N concentration were influenced by the application of both inhibitors.
Soares, J.R., Cantarella, H., Menegale, M.L.d.C., 2012. Ammonia volatilization losses from surface-applied urea with urease and nitrification inhibitors. Soil Biology and Biochemistry 52, 82-89
ReplyDeleteUrease inhibitor (UI) and nitrificationinhibitor (NI) have the potential to improve N-use efficiency of applied urea and minimize N losses via gaseous emissions of ammonia (NH3) to the atmosphere and nitrate View the MathML source leaching into surface and ground water bodies. There is a growing interest in the formulations of coating chemical fertilizers with both UI and NI. However, limited information is available on the combined use of UI and NI applied with urea fertilizer. Therefore the aim of this study was to investigate the effects of treating urea with both UI and NI to minimize NH3 volatilization. Two experiments were set up in volatilization chambers under controlled conditions to examine this process. In the first experiment, UR was treated with the urease inhibitor NBPT [N-(n-butyl) thiophosphoric acid triamide] at a rate of 1060 mg kg−1 urea and/or with the nitrificationinhibitor DCD (dicyandiamide) at rates equivalent to 5 or 10% of the urea N. A randomized experimental design with five treatments and five replicates was used: 1) UR, 2) UR + NBPT, 3) UR + DCD 10%, 4) UR + NBPT + DCD 5%, and 5) UR + NBPT + DCD 10%. The fertilizer treatments were applied to the surface of an acidic Red Latosol soil moistened to 60% of the maximum water retention and placed inside volatilization chambers. Controls chambers were added to allow for NH3 volatilized from unfertilized soil or contained in the air that swept over the soil surface. The second experiment had an additional treatment with surface-applied DCD. The chambers were glass vessels (1.5 L) fit with air inlet and outlet tubings to allow air to pass over the soil. Ammonia volatilized was swept and carried to a flask containing a boric acid solution to trap the gas and then measured daily by titration with a standardized H2SO4 solution. Continuous measurements were recorded for 19 and 23 days for the first and second experiment, respectively. The soil samples were then analyzed for UR–, View the MathML source, and View the MathML source. Losses of NH3 by volatilization with unamended UR ranged from 28 to 37% of the applied N, with peak of losses observed the third day after fertilization. NBPT delayed the peak of NH3 losses due to urease inhibition and reduced NH3 volatilization between 54 and 78% when compared with untreated UR. Up to 10 days after the fertilizer application, NH3 losses had not been affected by DCD in the UR or the UR + NBPT treatments; thereafter, NH3 volatilization tended to decrease, but not when DCD was present. As a consequence, the addition of DCD caused a 5–16% increase in NH3 volatilization losses of the fertilizer N applied as UR from both the UR and the UR + NBPT treatments. Because the effectiveness of NBPT to inhibit soil urease activity was strong only in the first week, it could be concluded that DCD did not affect the action of NBPT but rather, enhanced volatilization losses by maintaining higher soil View the MathML source concentration and pH for a longer time. Depending on the combination of factors influencing NH3 volatilization, DCD could even offset the beneficial effect of NBPT in reducing NH3 volatilization losses.
Zaman, M., Nguyen, M.L., 2012. How application timings of urease and nitrification inhibitors affect N losses from urine patches in pastoral system. Agriculture, Ecosystems & Environment 156, 37-48
ReplyDeleteIn intensively dairy-grazed pastoral systems, urine patches are the major source of nitrogen (N) losses via gaseous emissions of ammonia (NH3) and nitrous oxide (N2O) and nitrate (NO3−) leaching. Minimizing these N losses can therefore enable substantial economic and environmental gains. However, the current practice like the blanket application of nitrification inhibitor (NI) such as dicyandiamide (DCD) in suspension form after grazing is not effective at reducing these N losses. The objective of this study was to identify the best time to apply a combination of urease (UI) and NI inhibitors to reduce these N losses from urine patches. A field experiment on Typic Haplustepts silt loam soil, near Lincoln, Canterbury, New Zealand was conducted. The treatments included: a control (no urine or inhibitor), urine alone at 600 kg N ha−1, and urine with either double inhibitor (DI) in solid form which consists of a mixture (1:7 ratio w/w) of UI (N-(n-butyl) thiophosphoric triamide (nBTPT-trade name Agrotain®) and DCD or DCD alone at 10 kg ha−1 in suspension form. The DI or DCD was applied to undisturbed lysimeters/field plots 10 and 5 days prior to, the same day, and 5 days after urine application in autumn (May 2008) and again to new lysimeters and field plots in spring (September 2008). Overall there were 10 treatments: control, urine alone and urine with DI or DCD applied at the time of urine application, 5 days before or after urine application and 10 days before urine application. After these treatment applications in 2 seasons, soil ammonium (NH4+) and NO3− concentrations, soil pH, gaseous emissions of NH3 and N2O, and NO3− leaching were monitored for different period of time and pasture growth and N uptake were measured over a year. The DI applied 5 days prior to urine application was more effective in reducing the 3 N losses of NH3 volatilization, N2O emissions and NO3− leaching than its corresponding or DCD treatment applied 5 days after urine application. The DI applied 5 days prior to urine application significantly reduced soil NH4+ and NO3− production from applied urine and thus exhibited a minimal increase in soil pH compared with urine alone or with DCD treatments for 4–6 weeks during the two seasons. DCD consistently increased NH3 volatilization when applied 5 or 10 days prior to or concurrently with urine, however it decreased N2O emissions compared to urine alone in both seasons. Applying DI 5 days prior to urine application not only decreased N2O emissions as much as DCD did, it also significantly decreased NH3 volatilization by 38% in autumn and 28% in spring compared to urine alone. Applying DCD or DI in autumn was more effective than spring applications probably because of the lower soil temperature (<10 °C) in autumn. Compared to urine alone, DI and DCD applied 5 days prior to urine application in autumn significantly reduced NO3− leaching by 58% and 43%, respectively since the leaching events occurred during the time when these inhibitors were effective (1–2 weeks for nBTPT and 4–6 weeks for DCD). Neither the DI nor DCD had any such significant effect on NO3− leaching losses after their spring application because the leaching events occurred 3–5 months after inhibitor application, which was beyond the time that these inhibitors could be effective. Pasture productivity was only significantly increased by the DI after autumn application, but no significant trend was observed after spring application. These results suggest that DI applied in solid form prior to grazing has the most potential to reduce the 3 key N losses in grazed pastoral system; and it therefore warrants further research to improve its longevity to control N losses for a longer period.
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