Effects of different biochars and digestate on N2O fluxes under field conditions

Dicke, Christiane; Andert, Janet; Ammon, Christian; Kern, Jürgen; Meyer‐Aurich, Andreas; Kaupenjohann, Martin

doi:10.1016/j.scitotenv.2015.04.005

Cited by 35 publications

(18 citation statements)

References 46 publications

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“…Thus no significant changes in the abundance of the denitrifying microbial community were observed in response to soil biochar amendment. No significant effect of biochar on gene copy numbers of functional denitrification genes has also been reported in other studies7576. In contrast to our results on gene copy numbers, soil biochar amendment significantly increased nirK , typical nosZ , and atypical nosZ transcript copy numbers.…”

Section: Discussioncontrasting

confidence: 92%

Gas entrapment and microbial N2O reduction reduce N2O emissions from a biochar-amended sandy clay loam soil

Harter

Guzman-Bustamante

Kuehfuss

et al. 2016

Sci Rep

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Nitrous oxide (N2O) is a potent greenhouse gas that is produced during microbial nitrogen transformation processes such as nitrification and denitrification. Soils represent the largest sources of N2O emissions with nitrogen fertilizer application being the main driver of rising atmospheric N2O concentrations. Soil biochar amendment has been proposed as a promising tool to mitigate N2O emissions from soils. However, the underlying processes that cause N2O emission suppression in biochar-amended soils are still poorly understood. We set up microcosm experiments with fertilized, wet soil in which we used 15N tracing techniques and quantitative polymerase chain reaction (qPCR) to investigate the impact of biochar on mineral and gaseous nitrogen dynamics and denitrification-specific functional marker gene abundance and expression. In accordance with previous studies our results showed that biochar addition can lead to a significant decrease in N2O emissions. Furthermore, we determined significantly higher quantities of soil-entrapped N2O and N2 in biochar microcosms and a biochar-induced increase in typical and atypical nosZ transcript copy numbers. Our findings suggest that biochar-induced N2O emission mitigation is based on the entrapment of N2O in water-saturated pores of the soil matrix and concurrent stimulation of microbial N2O reduction resulting in an overall decrease of the N2O/(N2O + N2) ratio.

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Section: Discussioncontrasting

confidence: 92%

Gas entrapment and microbial N2O reduction reduce N2O emissions from a biochar-amended sandy clay loam soil

Harter

Guzman-Bustamante

Kuehfuss

et al. 2016

Sci Rep

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“…Throughout our study period (i.e., the rice growing season), biochar treatments caused notable decreases in cumulative N 2 O emissions compared with non-biochar treatment (Figure 4). This result corroborates previous studies that biochar application to agriculture soil can efficiently mitigate N 2 O emissions (Dicke et al, 2015;Hagemann et al, 2017;Sun et al, 2017). Interestingly, there were no spikes of N 2 O emissions after N fertilization events in our study, which might be related to the gas sampling at wide time intervals.…”

Section: Discussionsupporting

confidence: 93%

Peer Review #2 of "Biochar prepared at different pyrolysis temperatures affects urea-nitrogen immobilization and N2O emissions in paddy fields (v0.1)"

2019

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Background. Food safety has become a major issue, with serious environmental pollution resulting from losses of nitrogen (N) fertilizers. N is a key element for plant growth and is often one of the most important yield-limiting nutrients in paddy soil. Urea-N immobilization is an important process for restoring the levels of soil nutrient depleted by rice production and sustaining productivity. The benefits of biochar application include improved soil fertility, altered N dynamics, and reduced nutrient leaching. However, due to high variability in the quality of biochar, the responses of N loss and rice productivity to biochar amendments, especially those prepared at different pyrolysis temperatures, are still unclear. The main objectives of the present study were to examine the effects of biochar prepared at different pyrolysis temperatures on fertilizer N immobilization in paddy soil and explore the underlying mechanisms. Methods. Two biochar samples were prepared by pyrolysis of maize straw at 400°C (B400) and 700°C (B700), respectively. The biochar was applied to paddy soil at three rates (0, 0.7, and 2.1%, w/w), with or without N fertilization (0, 168, and 210 kg N ha-1). Pot experiments were performed to determine nitrous oxide (N 2 O) emissions and 15 N recovery from paddy soil using a 15 N tracer across the rice growing season. Results. Compared with the non-biochar control, biochar significantly decreased soil bulk density while increasing soil porosity, irrespective of pyrolysis temperature and N fertilizer level. Under B400 and B700, a high biochar rate decreased N loss rate to 66.42 and 68.90%, whereas a high N level increased it to 77.21 and 76.99%, respectively. Biochar also markedly decreased N 2 O emissions to 1.06 (B400) and 0.75 kg ha −1 (B700); low-N treatment caused a decrease in N 2 O emissions under B400, but this decrease was not observed under B700. An application rate of biochar of 2.1% plus 210 kg ha −1 N fertilizer substantially decreased the N fertilizer-induced N 2 O emission factor under B400, whereas under B700 no significant difference was observed. Biochar combined with N fertilizer treatment decreased rice biomass and grain yield by an average of 51.55 and 23.90 g pot-1 , respectively, but the yield reduction under B700 was lower than under B400. Conclusion. Irrespective of pyrolysis temperature, biochar had a positive effect on residual soil 15 N content, while it negatively affected the 15 N recovery of rice, N 2 O emissions from soil, rice biomass, and grain yield in the first year. Generally, a high application rate of biochar prepared at high or low pyrolysis temperature reduced the N fertilizer-induced N 2 O emission factor considerably. These biochar effects were dependent on N fertilizer level, biochar application rate, and their interactions.

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“…An additional environmental benefit of nutrient sorption by biochar is the potential to mitigate the microbial production of N 2 O following digestate application. Dicke et al (2015) studied the effect of biochar material and digestate on N 2 O fluxes under field conditions and showed that the addition of biochar reduced N 2 O emissions, although the emission of N 2 O was mostly influenced by temperature and precipitation. It could be argued that the higher specific surface area of the activated carbon is better than the biochar material thus making it a more reliable resource for microbial cell immobilization and the sorption of contaminants (Wang & Han, 2012).…”

Section: Nutrient Retentionmentioning

confidence: 99%

“…A better approach may be to focus on increasing the nutrient retention capacity of the digestate material. There is a growing interest in the use of biochar in AD to both increase the recovery rate of the process during SII and decrease the nutrient loss before and after land application (Mumme et al, 2014;Dicke et al, 2015;Cai et al, 2016;Lü et al, 2016;Sunyoto et al, 2016). This will potentially increase the operation of mono-substrate AD, which is often used by single substrate onsite AD operators, increase nutrient availability during digestate application to land and reduce the environmental implications of diffuse pollution and nutrient leaching.…”

Section: Introductionmentioning

confidence: 99%

The challenges of anaerobic digestion and the role of biochar in optimizing anaerobic digestion

et al. 2017

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Biochar, like most other adsorbents, is a carbonaceous material, which is formed from the combustion of plant materials, in low-zero oxygen conditions and results in a material, which has the capacity to sorb chemicals onto its surfaces. Currently, research is being carried out to investigate the relevance of biochar in improving the soil ecosystem, digestate quality and most recently the anaerobic digestion process. Anaerobic digestion (AD) of organic substrates provides both a sustainable source of energy and a digestate with the potential to enhance plant growth and soil health. In order to ensure that these benefits are realised, the anaerobic digestion system must be optimized for process stability and high nutrient retention capacity in the digestate produced. Substrate-induced inhibition is a major issue, which can disrupt the stable functioning of the AD system reducing microbial breakdown of the organic waste and formation of methane, which in turn reduces energy output. Likewise, the spreading of digestate on land can often result in nutrient loss, surface runoff and leaching. This review will examine substrate inhibition and their impact on anaerobic digestion, nutrient leaching and their environmental implications, the properties and functionality of biochar material in counteracting these challenges.

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Effects of different biochars and digestate on N2O fluxes under field conditions

Cited by 35 publications

References 46 publications

Gas entrapment and microbial N2O reduction reduce N2O emissions from a biochar-amended sandy clay loam soil

Gas entrapment and microbial N2O reduction reduce N2O emissions from a biochar-amended sandy clay loam soil

Peer Review #2 of "Biochar prepared at different pyrolysis temperatures affects urea-nitrogen immobilization and N2O emissions in paddy fields (v0.1)"

The challenges of anaerobic digestion and the role of biochar in optimizing anaerobic digestion

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