Abstract An incubation study with four contrasting soils (Vertosol, Ferrosol, Calcarosol and Tenosol) and three biochars (oil mallee [OM-], wheat chaff [W-]) and poultry litter [PL-] all produced at 550 °C) applied at 1% w/w to each of the soils was conducted (n = 4). The soils were packed in cylindrical chambers and were subjected to five cycles of four weeks of wetting and four weeks of drying. The soils received 10 atom % 15N-KNO3− in the 1st and 5th wetting cycles. Two of the four soils (Ferrosol and Tenosol) were applied with labile carbon (C) between the 2nd and 5th wetting cycle, while the other two soils (Vertosol and Calcarosol) were amended with labile C in the 5th wetting cycle only. Peak nitrous oxide (N2O) emissions in the Tenosol, Ferrosol and Calcarosol occurred within the 1st wetting cycle, whereas the Vertosol without labile C did not emit N2O. However, the co-application of labile C with 15N-NO3− to the Vertosol in the 5th wetting supported N2O emissions. The greatest reduction in N2O emissions following biochar amendment occurred due to the use of OM-biochar in the Tenosol; which decreased the emissions from 1.95 kg N2O-N ha−1 to 0.58 kg N2O-N ha−1 across the first 4 wetting/drying cycles. The majority of N2O emissions occurred during the first wetting cycle (85% water filled porosity). In contrast, application of PL-biochar did not result in a statistically significant reduction in emission of N2O. Assessing the source of emissions, the initial N2O from the Ferrosol and the Calcarosol was principally from native N-sources, while in the Tenosol between 31–57% of N2O originated from the added NO3−. While biochars reduced the overall emissions of N2O in the Tenosol, they also reduced the proportion of the N2O originating from the supplied NO3− during the first wetting cycle, possibly by limiting NO3− availability to denitrifers. Towards the end of the incubation period bacterial nitrifier gene abundance (amoA) in the unamended Tenosol was lower (p
More than two thirds of global nitrous oxide (N2O) emissions originate from soil, mainly associated with the extensive use of nitrogen (N) fertilizers in agriculture. Although the interaction of black carbon with the N cycle has been long recognized, the impact of biochar on N2O emissions has only recently been studied. Herein we reflect on proposed hypotheses to explain N2O decrease with biochar, linking them to specific mechanisms for N2O formation and consumption in soil. Moreover, to assist ...
#3Bhupinderpal Singh(New South Wales Department of Primary Industries)H-Index: 4
Summary There is a limited understanding of the effects of soil properties on biochar carbon (C) stability. This knowledge is essential to evaluate the capacity of biochar for long-term soil C sequestration fully. In this study two biochars, produced by slow pyrolysis at 450 or 550 ◦ C from a δ 13 C-depleted (−36.4‰) Eucalyptus saligna Sm. woody material, were incubated in four soils (Inceptisol, Entisol, Oxisol and Vertisol) of contrasting chemical and mineralogical properties. The total biocha...
Application of poultry litter (PL) to soil can lead to substantial nitrous oxide (N2O) emissions due to the co-application of labile carbon (C) and nitrogen (N). Slow pyrolysis of PL to produce biochar may mitigate N2O emissions from this source, whilst still providing agronomic benefits. In a corn crop on ferrosol with similarly matched available N inputs of ca. 116 kg N/ha, PL-biochar plus urea emitted significantly less N2O (1.5 kg N2O-N/ha) compared to raw PL at 4.9 kg N2O-N/ha. Urea amendme...
Last. Elke Stehfest(Netherlands Environmental Assessment Agency)H-Index: 56
view all 10 authors...
Soil nitrogen (N) budgets are used in a global, distributed flow-path model with 0.5° × 0.5° resolution, representing denitrification and N2O emissions from soils, groundwater and riparian zones for the period 1900–2000 and scenarios for the period 2000–2050 based on the Millennium Ecosystem Assessment. Total agricultural and natural N inputs from N fertilizers, animal manure, biological N2 fixation and atmospheric N deposition increased from 155 to 345 Tg N yr−1 (Tg = teragram; 1 Tg = 1012 g) b...
Last. Daniel Murphy(UWA: University of Western Australia)H-Index: 62
view all 5 authors...
Abstract Nitrous oxide (N 2 O) emissions in semi-arid regions are often greater following summer rainfall events when the soil is fallow, than in response to N fertiliser applications during crop growth. Nitrogen fertiliser management strategies are therefore likely to be ineffective at mitigating N 2 O emissions from these cropped agricultural soils. Here we examined the influence of raising soil pH on N 2 O emissions, nitrification rates, and both nitrifier and denitrifier populations followin...
Agricultural soils represent the main source of anthropogenic N2O emissions. Recently, interactions of black carbon with the nitrogen cycle have been recognized and the use of biochar is being investigated as a means to reduce N2O emissions. However, the mechanisms of reduction remain unclear. Here we demonstrate the significant impact of biochar on denitrification, with a consistent decrease in N2O emissions by 10–90% in 14 different agricultural soils. Using the 15N gas-flux method we observed...
Last. Christoph Müller(Lincoln University (New Zealand))H-Index: 88
view all 4 authors...
Interest in biochar stems from its potential agronomic benefits and carbon sequestration ability. Biochar application alters soil nitrogen (N) dynamics. This review establishes emerging trends and gaps in biochar-N research. Biochar adsorption of NO3 − , up to 0.6 mg g −1 biochar, occurs at pyrolysis temperatures >600 °C with amounts adsorbed dependent on feedstock and NO3 − concentration. Biochar NH4 + adsorption depends on feedstock, but no pyrolysis temperature trend is apparent. Long-term pr...
Last. Rodrick D. Lentz(ARS: Agricultural Research Service)H-Index: 25
view all 5 authors...
It has been demonstrated that soil amended with biochar, designed specifically for use as a soil conditioner, results in changes to the microbial populations that reside therein. These changes have been reflected in studies measuring variations in microbial activity, biomass, and community structure. Despite these studies, very few experiments have been performed examining microbial genes involved in nutrient cycling processes. Given the paucity of research in this area, we designed a six-month ...
This study investigated the effect of municipal solid waste (MSW) compost (0, 50, and 100 t/ha) on N cycling and the microorganisms involved in it, in a clay-loam soil. After a release of nitrates (NO3 −-N) in the first 6 days after compost incorporation, soil NO3 −-N content remained constant in all the treatments until day 62, suggesting N immobilization induced by the soil used in this study. Then, soil NO3 −-N content increased in all treatments and especially in the highest compost dose, pr...
Last. Jizhong Zhou(OU: University of Oklahoma)H-Index: 124
view all 8 authors...
Various agriculture management practices may have distinct influences on soil microbial communities and their ecological functions. In this study, we utilized GeoChip, a high-throughput microarray-based technique containing approximately 28,000 probes for genes involved in nitrogen (N)/carbon (C)/sulfur (S)/phosphorus (P) cycles and other processes, to evaluate the potential functions of soil microbial communities under conventional (CT), low-input (LI), and organic (ORG) management systems at a...
#2Muhammad Riaz(SCAU: South China Agricultural University)H-Index: 62
Last. Cuncang Jiang(Xinjiang Production and Construction Corps)
view all 7 authors...
Abstract null null The situation of imbalance application of nitrogenous fertilizers in maize production is a serious issue in China, and excessive nitrogen (N) application is hazardous to sustainable agricultural production and environment. In this experiment, two biochar levels (C0: 0, C1: 2 %), three different N rates (N1: 50, N2: 100, and N3: 200 mg kg−1), and two fertilization methods (T: traditional N fertilizer application mode and D: deep N fertilizer placement mode) were set up to study...
Abstract null null Addition of biochar and straw has constituted an effective way to improve soil fertility in tobacco fields. However, little is known about the effects of these amendments on CH4 and N2O emissions and their potential microbial mechanisms. Here, we conducted an experiment in tobacco-planted soil using four treatments: mineral fertilizers only (F), biochar with mineral fertilizers (BF), wheat straw with mineral fertilizers (SF), and biochar + wheat straw with mineral fertilizers ...
Abstract null null Extensive reports on research into the effects of biochar additions on soil-plant systems show many inconsistencies in the response of various parameters including nitrogen (N) transformations. This review focusses on the use of the stable isotope 15N to provide unique information about the N dynamics in biochar-amended systems. The properties of biochars and their impacts on N cycling depends on the feedstock and pyrolysis parameters, as well as the soil type, plant species a...
This study aimed to explore the effects of biochar on pulse CO2 and N2O emissions and N cycling microbial functional genes after a short-term drought through a soil incubation experiment. Soil samples were collected in a macadamia orchard where biochar was applied 5 years prior to the incubation. Samples were wetted after being subjected to short-term (2-month) drought conditions. Samples were analysed for gas emissions (N2O and CO2), available NH4+-N, and NO3−-N, water soluble organic carbon (W...
Last. Noura Ziadi(AAFC: Agriculture and Agri-Food Canada)H-Index: 39
view all 3 authors...
Biochar, a carbon-rich material produced by the pyrolysis of organic residues, is frequently used as a soil amendment to enhance soil fertility and improve soil properties in tropical climates. How...
Continuous increase in the population of the world along with multiple nutrient deficiencies and poor water use efficiency offers a challenging scenario for agriculture sector to meet the increasing demand of food. Use of organic amendments like biochar and compost has been suggested as a novel approach for restoration of degraded soil further improving crop productivity and water productivity. Thus here, we have reviewed the publications on individual and combined application of biochar and com...
Abstract While there is a sound understanding of the range of mechanisms by which biochar can contribute to the mitigation of soil N2O emissions, a paucity of information remains on the efficacy and mechanisms associated with biochar-based fertilizer (BF). The present 12-month field trial aimed to: (1) investigate the responses of the seasonal variations in soil N2O emissions and environmental factors, including soil temperature and moisture content, concentrations of NH4+-N, NO3−-N, water-solub...
Abstract null null Nitrous oxide (N2O) is a potent atmospheric greenhouse gas that is largely emitted from soils due to the enhanced use of reactive nitrogen in agriculture and plantations. In this study, we evaluated the N2O mitigation ability of biochar after 7 years of application in a poplar plantation. The field experiment was based on combinations of three biochar (0, 80, and 120 t ha−1) and four biogas slurry (0, 125, 250, and 375 m3 ha−1) rates following a factorial design. N2O flux rate...
Abstract null null Despite improving soil quality and reducing nitrogen (N) loss in paddy soil, replacing chemical fertilizer with organic fertilizer would significantly accelerate greenhouse gas emission in terms of methane (CH4). The application of slow-release fertilizer has been proposed an effective approach to control CH4 emissions, in addition to reducing N loss. Yet, the understanding of CH4 emissions from paddy fields with the additions of different fertilizers is still less known. Ther...
Last. Wenfu Chen(Shenyang Agricultural University)H-Index: 13
view all 8 authors...
N2O emission from paddy soil is a potential environmental risk, especially when the soil moisture content of paddy soil changes and excessive nitrogen retention occurs. Biochar is known to have a positive effect on reducing N2O emissions. However, the influence of different types of biochar on N2O emission with varying soil moisture contents is unclear. The objective of this study was to investigate the effects of biochar made from different feedstocks and at different pyrolysis temperatures on ...
