ArticlePublisher preview available

Elevation of biochar application as regulator on denitrification/NH3 volatilization in saline soils

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract and Figures

Denitrification and NH3 volatilization are the main removal processes of nitrogen in coastal saline soils. In this incubation study, the effects of wheat straw biochar application at rates of 0, 2, 5, 10 and 15% by weight to saline soil with two salt gradients of 0 and 1‰ on denitrification and NH3 volatilization were investigated. The results showed that the denitrification rates with 2, 5 and 10% biochar amendments decreased by 25.26, 33.07 and 17.50%, respectively, under salt-free conditions, and the denitrification rates with 2 and 5% biochar amendments under 1‰ salt conditions decreased by 17.74 and 17.39%, respectively. However, the NH3 volatilization rates increased by 8.05–61.73% after biochar application. The path analysis revealed the interactions of overlying water-sediment system environmental factors in biochar-amended saline soils and their roles in denitrification and NH3 volatilization. Environmental factors in sediment exerted much greater control over denitrification than those in overlying water. In addition, environmental factors exhibited an indirect negative influence on denitrification by negatively influencing the abundance of the nosZ gene. The comprehensive effects of the environmental factors in overlying water on NH3 volatilization were greater than those in sediment. The NH4+-N content, pH of overlying water and sediment salinity were the main controlling factors for NH3 volatilization in saline soils. Biochar application effectively regulated the denitrification rate by changing the environmental factors and denitrifying functional gene abundance, but its application posed a risk of increased NH3 volatilization mainly by increasing NH4+-N, EC and pH in overlying water.
This content is subject to copyright. Terms and conditions apply.
RESEARCH ARTICLE
Elevation of biochar application as regulator on denitrification/NH
3
volatilization in saline soils
Yongchun Pan
1
&Dongli She
1
&Xinyi Chen
1
&Yongqiu Xia
2
&Luís Carlos Timm
3
Received: 2 December 2020 /Accepted: 16 March 2021
#The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021
Abstract
Denitrification and NH
3
volatilization are the main removal processes of nitrogen in coastal saline soils. In this incubation study,
the effects of wheat straw biochar application at rates of 0, 2, 5, 10 and 15% by weight to saline soil with two salt gradients of 0
and 1on denitrification and NH
3
volatilization were investigated. The results showed that the denitrification rates with 2, 5 and
10% biochar amendments decreased by 25.26, 33.07 and 17.50%, respectively, under salt-free conditions, and the denitrification
rates with 2 and 5% biochar amendments under 1salt conditions decreased by 17.74 and 17.39%, respectively. However, the
NH
3
volatilization rates increased by 8.0561.73% after biochar application. The path analysis revealed the interactions of
overlying water-sediment system environmental factors in biochar-amended saline soils and their roles in denitrification and
NH
3
volatilization. Environmental factors in sediment exerted much greater control over denitrification than those in overlying
water. In addition, environmental factors exhibited an indirect negative influence on denitrification by negatively influencing the
abundance of the nosZ gene. The comprehensive effects of the environmental factors in overlying water on NH
3
volatilization
were greater than those in sediment. The NH
4
+
-N content, pH of overlying water and sediment salinity were the main controlling
factors for NH
3
volatilization in saline soils. Biochar application effectively regulated the denitrification rate by changing the
environmental factors and denitrifying functional gene abundance, but its application posed a risk of increased NH
3
volatilization
mainly by increasing NH
4
+
-N, EC and pH in overlying water.
Keywords Coastal area .Denitrification .NH
3
volatilization .Path analysis .Biochar
Introduction
Nitrogen (N) is an essential nutrient required for high yields of
agricultural crops. The loss of N fertilizer from soil restricts the
efficient utilization of agricultural nutrients (Cui et al. 2014).
The utilization efficiency of N fertilizer in the crop growing
season in China is only 3035%, according to an investigation
by the Chinese Ministry of Agriculture (Kong 2014;Ma
et al. 2014). High amounts of nitrogen entering the environment
have caused a series of severe ecological and environmental
problems, such as soil quality degradation, air pollution, acid
rain formation, water eutrophication, and biodiversity reduction
(Jäger et al. 2011;Quirin2013; Zhu and Chen 2002). Minimal
amounts of nitrogen are lost from paddy fields through rainwa-
ter leaching and surface runoff (Zhao et al. 2010), while deni-
trification and NH
3
volatilization are the main ways of nitrogen
loss on cropland (Almaraz et al. 2020; Li and Lang 2014;Pan
et al. 2016;Wangetal.2018a). The annual NH
3
emissions of
rice fields in China totals 0.3 Tg N, which is equivalent to 13.2
47% of the applied N (Cui et al. 2014;Paulotetal.2014), and
as much as 64% (mean of 17.6%) of applied N be lost as NH
3
worldwide (Pan et al. 2016); moreover, the amount of nitrogen
lost in denitrification can be more than 60% of the nitrogen
application amount (Möller and Stinner 2009).
Responsible Editor: Zhihong Xu
*Dongli She
shedongli@hhu.edu.cn
*Yongqiu Xia
yqxia@issac.ac.cn
1
College of Agricultural Sciences and Engineering, Hohai University,
Nanjing 210098, China
2
Key Laboratory of Soil and Sustainable Agriculture, Changshu
National Agro-Ecosystem Observation and Research Station,
Institute of Soil Science, Chinese Academy of Sciences,
Nanjing 210008, China
3
Department of Rural Engineering, Faculty of Agronomy, Federal
University of Pelotas, Campus Universitário s/n, CEP, Capão do
Leão, Rio Grande do Sul 96010-900, Brazil
https://doi.org/10.1007/s11356-021-13562-w
/ Published online: 31 March 2021
Environmental Science and Pollution Research (2021) 28:41712–41725
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Urea hydrolysis promotes NH 3 volatilization in flooded layer (Wang et al. 2012). The NH 3 volatilization was significantly correlated with the concentcing water (Pan et al. 2021) (Table 2, Fig. 6). The N loss of NH 3 volatilization is mainly concentrated in the tillering and jointing periods after applying fertilizer. ...
Article
Full-text available
Salt-affected soils have poor structure and physicochemical properties, which affect soil nitrogen cycling process closely related to the environment, such as denitrification and ammonia volatilization. Biochar and polyacrylamide (PAM) have been widely used as soil amendments to improve soil physicochemical properties. However, how they affect denitrification and ammonia volatilization in saline soils is unclear. In this study, the denitrification and ammonia volatilization rates were measured in a saline soil field ameliorated with three biochar application rates (0%, 2%, and 5%, w/w) and three PAM application rates (0‰, 0.4‰, and 1‰, w/w) over 3 years. The results showed that denitrification rates decreased by 23.63–39.60% with biochar application, whereas ammonia volatilization rates increased by 9.82–25.58%. The denitrification and ammonia volatilization rates decreased by 9.87–29.08% and 11.39–19.42%, respectively, following PAM addition. However, there was no significant synergistic effect of biochar and PAM amendments on the denitrification and ammonia volatilization rates. The addition of biochar mainly reduced the denitrification rate by regulating the dissolved oxygen and electrical conductivity of overlying water and absorbing soil nitrate nitrogen. Meanwhile, biochar application increased pH and stimulated the transfer of NH4+–N from soil to overlying water, thus increasing NH3 volatilization rates. Hence, there was a tradeoff between denitrification and NH3 volatilization in the saline soils induced by biochar application. PAM reduced the denitrification rate by increasing the infiltration inorganic nitrogen and slowing the conversion of ammonium to nitrate. Moreover, PAM reduced the concentration of NH4+–N in the overlying water through absorbing soil ammonium and inhibiting urea hydrolysis, thereby decreasing NH3 volatilization rate.
Article
Full-text available
Biochar amended soils reduce fertilizer N losses and suppress greenhouse gas emissions. However, biochar can increase NH3 volatilization. H2SO4-modified biochar has been studied as a means to achieve the advantages of biochar while reducing volatilization, especially under alternate wetting and drying irrigation (IAWD). In contrast to continuously flooded irrigation (ICF), IAWD is a water-saving technology that repeatedly dries and re-floods fields. A 3-year field experiment was conducted with two irrigation regimes (ICF and IAWD) as main plots and 0 (control), 20 t ha-1 biochar, and 20 t ha-1 H2SO4-modified biochar as subplots. IAWD produced 7.6-14.8% more reactive gaseous N losses (NH3 and N2O) and emitted 2.02 times N-related global warming potential (GWPN) of ICF. Biochar increased NH3 volatilization by 35.6% in the first year and decreased it by 22.4% and 24.8% in the second and third years, respectively, while H2SO4-modified biochar decreased NH3 volatilization each year. The increased NH3 volatilization was caused by the higher NH4 + concentration and pH in the floodwater and surface soil due to increasing N inputs and alkalinity from biochar. The decrease in the following two years was attributed to pH returning to the pre-treatment level and continued biochar absorption of NH4 + from the floodwater. Both biochar and H2SO4-modified biochar significantly reduced seasonal N2O emissions. H2SO4-modified biochar coupled with IAWD mitigated the initial increases in NH3 volatilization and reactive gaseous N losses in the first year, and increased grain yield, decreased reactive gaseous N losses, and GWPN compared with the IAWD without biochar throughout the three years. The use of acid-modified biochar could produce higher grain yield with lower reactive gaseous N losses and GWPN for application in the IAWD paddy systems, which benefits sustainable agricultural production. J o u r n a l P r e-p r o o f 2
Preprint
Full-text available
NH 3 from farmland has serious impacts on human health and ecosystems. To reduce NH 3 volatilization and increase yield, biochar is applied. A field experiment was carried out to study NH 3 volatilization loss, and summer maize yield was analysed under different irrigation schemes with different amounts of biochar. Two irrigation schemes, I1 (67.5 mm) and I2 (121.5 mm), were set up according to the irrigation habits of local producers. Three biochar application rates were selected: C1 (0 t ha ⁻¹ ), C2 (20 t ha ⁻¹ ) and C3 (40 t ha ⁻¹ ). The relationship between NH 3 volatilization and influencing factors, including NH 4 ⁺ -N concentration, NO 3 ⁻ -N concentration, pH in the 0~20 cm soil layer and temperature, was investigated. The results showed that the yield significantly ( p <0.05) increased by 17.27%~46.67% after applying biochar. Compared with C1, NH 3 volatilization significantly ( p <0.05) decreased by 28.98%~31.63% in C2, while that in C3 significantly ( p <0.05) increased by 22.64%~73.87%. The effects of biochar on NH 3 volatilization were consistent under different irrigation conditions. Compared to I1, I2 not only increased the yield of summer corn but also increased the risk of NH 3 volatilization and leaching. NH 3 volatilization was positively correlated with NH 4 ⁺ -N concentration, pH and temperature, but it was negatively correlated with NO 3 ⁻ -N concentration. These results suggest that the optimal application amount of biochar for summer maize ranges from 14.59 t ha ⁻¹ to 17.19 t ha ⁻¹ in the study area.
Article
Full-text available
In a 338-d microcosm incubation experiment, greenhouse gas emissions (GHG) and bacterial diversity were studied in a clayey soil amended with 5% (w/w) biochar in the presence or absence of 4% (w/w) peat- and shrimp-based compost used as an additional C source. Two maple biochars produced at 400 °C (M400) or 700 °C (M700) and pine chips produced at 700 °C (P700) were tested. In comparison with soil supplemented or not with compost, the addition of any biochar resulted in lower total cumulative N2O emission (90% to 97%). The low porosity of M400 and M700 increased soil anaerobic conditions and resulted in higher total cumulative CH4 emission compared to the other soil treatments. In addition, the lowest total cumulative CO2 emission was observed with M700, probably due to its low-priming effect on native soil C decomposition. In all treatments, compost addition had the highest impact on both soil bacterial richness and community composition, particularly on bacteria of the class Anaerolineae. At day 338, results showed that modification of soil properties by maple biochars reduced bacterial diversity and induced shifts in the taxonomic composition of their community. In fact, heterotrophic bacteria involved in denitrification, such as genera Haliangium, Hyphomicrobium, Opititus, and Pedomicrobium, increased in abundance in response to the amendment with maple biochars. We conclude that the nature of biochar feedstock can impact soil bacterial diversity by changing soil physicochemical properties, thus influencing C dynamics, porosity, and pH, and by mitigating total cumulative GHG emissions.
Article
Full-text available
The influence of soil pH changes by liming on denitrification and denitrifier gene abundance under different biogeochemical conditions by amending two contrasting soils with water, cattle urine (600 mg N kg−1 soil) and urine + dicyandiamide (DCD) (10 mg kg−1 soil) and incubating at 10 °C and 15 °C was evaluated. Liming increased N2O emission, denitrification rate and denitrifier gene abundance in both soils. The increase in N2O and denitrification with liming was higher in fluvial soil (24% increase in N2O and 22% increase in denitrification) than in allophanic soil (16% in N2O and 19% increase in denitrification). There was more N2O coming from urine applied to limed soil than that from urine to un-limed soil. Addition of DCD with urine reduced both N2O emission and denitrification; the reduction was greater in limed soil than in un-limed soil. Results of quantitative polymerase chain reaction (qPCR) of bacterial denitrifier genes (nirS, nirK and nosZ genes) indicate that liming-induced soil pH changes increased denitrifier gene abundance and caused more complete bacterial denitrification in urine-amended soils. These results suggest that liming grazed pasture soils induces complete denitrification, which may mitigate N2O emissions
Article
Full-text available
Denitrification plays a critical role in regulating ecosystem nutrient availability and anthropogenic reactive nitrogen (N) production. Its importance has inspired an increasing number of studies, yet it remains the most poorly constrained term in terrestrial ecosystem N budgets. We censused the peer‐reviewed soil denitrification literature (1975 to 2015) to identify opportunities for future studies to advance our understanding despite the inherent challenges in studying the process. We found that only one‐third of studies reported estimates of both nitrous oxide (N2O) and dinitrogen (N2) production fluxes, often the dominant end products of denitrification, while the majority of studies reported only net N2O fluxes or denitrification potential. Of the 236 studies that measured complete denitrification to N2, 49% used the acetylene inhibition method; 84% were conducted in the laboratory; 81% were performed on surface soils (0‐20 cm depth); 75% were located in North America and Europe; and 78% performed treatment manipulations, mostly of N, carbon, or water. To improve understanding of soil denitrification, we recommend broadening access to technologies for new methodologies to measure soil N2 production rates, conducting more studies in the tropics and on subsoils, performing standardized experiments on unmanipulated soils, and using more precise terminology to refer to measured process rates (e.g., net N2O flux or denitrification potential). To overcome the greater challenges in studying soil denitrification, we envision coordinated research efforts based on standard reporting of metadata for all soil denitrification studies, standard protocols for studies contributing to a Global Denitrification Research Network, and a global consortium of denitrification researchers to facilitate sharing ideas, resources, and to provide mentorship for researchers new to the field.
Article
Full-text available
Biochar application to croplands has been proposed as a potential strategy to decrease losses of soil‐reactive nitrogen (N) to the air and water. However, the extent and spatial variability of biochar function at the global level are still unclear. Using Random Forest regression modelling of machine learning based on data compiled from the literature, we mapped the impacts of different biochar types (derived from wood, straw, or manure), and their interactions with biochar application rates, soil properties and environmental factors, on soil N losses (NH3 volatilization, N2O emissions, and N leaching) and crop productivity. The results show that a suitable distribution of biochar across global croplands (i.e., one application of <40 t ha⁻¹ wood biochar for poorly buffered soils, such as those characterized by soil pH<5, organic carbon<1%, or clay>30%; and one application of <80 t ha⁻¹ wood biochar, <40 t ha⁻¹ straw biochar, or <10 t ha⁻¹ manure biochar for other soils) could achieve an increase of global crop yields by 222~766 Tg yr⁻¹ (4~16% increase), a mitigation of cropland N2O emissions by 0.19~0.88 Tg N yr⁻¹ (6~30% decrease), a decline of cropland N leaching by 3.9~9.2 Tg N yr⁻¹ (12~29% decrease), but also a fluctuation of cropland NH3 volatilization by ‐1.9~4.7 Tg N yr⁻¹ (‐12~31% change). The decreased sum of the three major reactive N losses amount to 1.7~9.4 Tg N yr⁻¹, which corresponds to 3~14% of the global cropland total N loss. Biochar generally has a larger potential for decreasing soil N losses but with less benefits to crop production in temperate regions than in tropical regions. This article is protected by copyright. All rights reserved.
Article
Salinization stands among the most prominent environmental hazards of the largest delta on Earth, the Bengal delta. It has significant impacts on the local societies and the economy. Using an unprecedented collection of in situ river salinity records over the Bengal delta, extending from the Hooghly estuary in the west to the Meghna estuary in the east, we report a sudden salinization of the central part of the delta that occurred in 2006–2007. This results in a sudden landward shift of the seasonal march of the salinity front by about 20 km, taking place in the pre-monsoon season. Such a regime shift was never reported before. We investigate the various drivers of this sudden change and identify three possible forcing factors: the decrease in Ganges freshwater discharge, the rise of sea level and the depletion of the groundwater level. These factors may act independently, or in concert. Given the threat of the ongoing climate change and its cohort of adverse effects expected in the course of the 21st century in the Bengal delta, our study contributes to set the observational basis for the development of the next generation of salinization modeling platforms.
Article
Nitrogen contamination remains a severe environmental problem and a major threat to sustainable development worldwide. A systematic analysis of the literature indicates that the partial nitritation-anammox (PN/AMX) process is still actively studied as a viable option for energy-efficient and feasible technology for the sustainable treatment of N- rich wastewaters, since its initial discovery in 1990. Notably, the mainstream PN/AMX process application remains the most challenging bottleneck in AMX technology and fascinates the world's attention in AMX studies. This paper discusses the recent trends and developments of PN/AMX research and analyzes the results of recent years of research on the PN/AMX from lab-to full-scale applications. The findings would deeply improve our understanding of the major challenges under mainstream conditions and next-stage research on the PN/AMX process. A great deal of efforts has been made in the process engineering, PN/AMX bacteria populations, predictive modeling, and the full-scale implementations during the past 22 years. A series of new and excellent experimental findings at lab, pilot and full-scale levels including good nitrogen removal performance even under low temperature (15-10 °C) around the world were achieved. To date, pilot- and full-scale PN/AMX have been successfully used to treat different types of industrial sewage, including black wastewater, sludge digester liquids, landfill leachate, monosodium glutamate wastewater, etc. Supplementing the qualitative analysis, this review also provides a quantitative bibliometrics study and evaluates global perspectives on PN/AMX research published during the past 22 years. Finally, general trends in the development of PN/AMX research are summarized with the aim of conveying potential future trajectories. The current review offers a valuable orientation and global overview for scientists, engineers, readers and decision makers presently focusing on PN/AMX processes.
Article
The Yangtze River, which is the largest in Euro-Asian, receives tremendous anthropogenic nitrogen input and is typically characterized by severe eutrophication and hypoxia. Two major processes, denitrification and anaerobic ammonium oxidation (anammox), play vital roles for removing nitrogen global in nitrogen cycling. In the current study, sediment samples were collected from both latitudinal and longitudinal transects along the coastal Yangtze River and the East China Sea (ECS). We investigated community composition and distributions of nosZ gene-encoded denitrifiers by high throughput sequencing, and also quantified the relative abundances of both denitrifying and anammox bacteria by q-PCR analysis. Denitrifying communities showed distinct spatial distribution patterns that were impacted by physical (water current and river runoffs) and chemical (nutrient availability and organic content) processes. Both denitrifying and anammox bacteria contributed to the nitrogen removal in Yangtze Estuary and the adjacent ECS, and these two processes shifted from coastal to open ocean with reverse trends: the abundance of nosZ gene decreased from coastal to open ocean while anammox exhibited an increasing trend based on quantifications of hzsB and 16S rRNA genes. Further correspondence correlation analysis revealed that salinity and nutrients were the main factors in structuring composition and distribution of denitrifying and anammox bacteria. This study improved our understanding of dynamic processes in nitrogen removal from estuarine to open ocean. We hypothesize that denitrification is the major nitrogen removal pathway in estuaries, but in open oceans, low nutrient and organic matter concentrations restrict denitrification, thus increasing the importance of anammox as a nitrogen removal process.
Article
There has been increasing interest in and use of biochar as a soil amendment. However, the effects of biochar addition on ammonia volatilization (AV) appeared contradictory from the many reported studies and the main influencing factors remain unclear. Here, we conducted a comprehensive meta-analysis of 41 published articles with 144 observations to reveal the effects of biochar addition on AV and used a boosted regression tree modelling approach to further interpret the contribution of biochar characteristics, soil properties and experimental conditions to this process. On average, biochar addition did not impact on AV, but this varied greatly under different soil, biochar and experimental conditions. The pH of soil and biochar were important factors impacting AV. Biochar application to acidic soil could stimulate AV, and addition of biochar with a high pH and at a low application rate also showed the same trend. In contrast, combining biochar with urea or organic fertilizer, or using wood-based or acidified biochar at appropriate rates had benefits in reducing AV. These findings have major implications for biochar management strategies in agricultural systems, where an important consideration is the mitigation of potentially detrimental environmental consequences.
Article
Elevated salinity is expected to drive changes in biogeochemical cycling and microbial communities in estuarine and intertidal wetlands. However, limited information regarding the role of salinity in shaping biogeochemical controls and mediating greenhouse gas emissions is currently available. In this study, we used incubation experiment across salinity gradients of the estuarine and intertidal sediments to reveal the underlying interconnections of CH4 and N2O emissions, biogeochemical controls and salinity gradients. Our results indicated that sediment biogeochemical properties were significantly affected by the increasing salinity, which were attributed to the accelerated sediment enzyme activities. The increasing salinity promoted CH4 and N2O emission rates by stimulating organic carbon decomposition and nitrogen transformation rates. In addition, the copy number of mcrA, nirS and nirK genes increased along with the salinity gradients, which strongly mediated the CH4 and N2O emission rates. Stepwise regression analysis suggested that labile organic carbon and denitrification were the most crucial determinants of CH4 and N2O emission rates, respectively. Overall, salinity could enhance CH4 and N2O emission mainly by altering sediment geochemical variables, microbial activity and functional gene abundance in estuarine and intertidal environments. Furthermore, increasing salinity could enhance the carbon and nitrogen export, which may pose a threat to the ecological function of estuarine and intertidal ecosystems. This study may contribute to the knowledge about the importance of biogeochemical controls induced by salinity in mediating greenhouse gas emissions.