Direct and Indirect Effects of Urease and Nitrification Inhibitors on N2O-N Losses from Urea Fertilization to Winter Wheat in Southern Germany

Abstract

Urea (U) is the most important nitrogen (N) fertilizer in agriculture worldwide, and as N fertilizer can result in large gaseous losses of NH3 and N2O. Thus, urease inhibitors (UIs) and nitrification inhibitors (NIs) have been coupled with U fertilizers to mitigate NH3 and N2O emissions. However, it is still unclear whether adding NIs and/or UIs to U stimulates other pollutants, while reducing one pollutant. Furthermore, part of the NH3 deposition to earth is converted to N2O, leading to indirect N2O emission. To estimate direct and indirect effect of UIs and NIs on the N2O-N and NH3-N losses from U; therefore, we analyzed multi-year field experiments from the same site during 2004 to 2005 and 2011 to 2013. The field experiments with U fertilization with or without UI (IPAT, N-isopropoxycarbonyl phosphoric acid triamide) and NI (DCD/TZ, Dicyandiamide/1H-1, 2, 4-Triazol) in winter wheat and with calcium ammonium nitrate (CAN) were conducted in southern Germany. Fluxes of NH3 or N2O emissions were determined following each split N fertilization in separate experiments on the same site. Our results showed that U with NIs considerably reduced N2O emissions, and adding UIs decreased NH3 emissions. However, the effect on N2O emissions exerted by (U + UIs) or (U + UIs + NIs) was inconsistent. In contrast to the treatment of (U + UIs + NIs), the addition of NIs alone to U stimulated NH3 emission compared to treatment with U. When 1% indirect N2O emission from NH3 (IPCC emission factor (EF4)) was considered to estimate the indirect N2O emission, total N2O emissions from (U + NIs) were approximately 29% compared to that from U alone and 36% compared to that from (U + UI), indicating that indirect N2O emission from NH3 induced by NIs may be negligible.

Neem oil and pomegranate leaf extract coating on urea to reduced nitrous oxide emission; improved nitrogen use efficiency and crop yield: A step towards sustainable N use and green production

“…Cumulative flux of N2O from wheat and rice was less than 1 kg N2O-N ha -1 during 60 days of sowing/transplanting (Table 3), out of 160 kg N ha -1 applied as urea. Many of the previous studies (Gupta et al, 2012;Aulakh et al, 2001;Hu et al, 2020) reported about similar N2O flux from wheat and rice crops. Optimum soil temperature for nitrification during wheat season (Fig 1) might be the reason for little higher N2O emission in wheat than in rice, as N2O emission is affected by many edaphic factors like soil and air temperature, moisture, N content and organic matter (Ni et al, 2014).…”

“…As expected, and in agreement to many other reports, the use of synthetic and natural nitrification inhibitors (DCD, neem oil and pomegranate leaf extract) improved rice and wheat yields and N related traits such as percent N recovery (PNR), partial factor productivity (PFP) and N uptake in grains compared to uncoated urea (Table 4). The improved growth may be attributed to increased N availability in the form of NH4 because of slowed nitrification process (Arora and Srivastava, 2013;Hu et al, 2020;Bordoloi et al, 2020). These NH4 + cations are strongly bound to the negatively charged clay particles electrostatically and the functional groups of soil organic matter (SOM) (Zaman et al, 2013).…”

“…De Klein and Eckard, (2008) and Ning et al (2018) stated that DCD proved effective in reducing N2O emissions from nitrogen fertilizers, urine (up to 90%), or livestock slurry, retaining N in the soil in the less mobile ammonium (NH4 + ) form. Many reports are available claiming the nitrification inhibition by DCD ranging from 10 to 53 % compared with conventional urea (Aita et al, 2018;Pathak et al, 2001;Hu et al, 2020;Raza et al, 2019).…”

Effect of Natural Liquid Hydroabsorbents on Ammonia Emission from Liquid Nitrogen Fertilizers and Plant Growth of Maize (Zea Mays L.) under Drought Conditions

“…However, the urea fertilizers are characteristic by high risk of nitrogen loss via volatilization, which can reach 20–30% under the normal conditions [ 8 ]. Urea applied to the dry soil surface without incorporation undergoes rapid hydrolysis to ammonia form [ 9 ], and the nitrogen loss can reach more than 50%, especially during warm weather [ 10 ]. Ammonia volatilization presents a significant reduction in nitrogen fertilization efficiency, resulting in economic loss.…”

Ammonia volatilization from fertilizer sources on a loam soil in Idaho

“…Urea fertilizer is the most widely used source of N for agricultural production globally (Cantarella et al., 2018; Hu et al., 2020; Pan et al., 2016), as well as in the United States (Woodley et al., 2020). Urea usage is widespread due to its low cost, high N content (46% N), and ease of transport as a stable dry‐granular substance.…”