CAS Nanjing Institute of Soil Science
CAS Nanjing Institute of Soil Science
Akiyama H.,Japan National Institute for Agro - Environmental Sciences |
Yan X.,CAS Nanjing Institute of Soil Science |
Yagi K.,Japan National Institute for Agro - Environmental Sciences
Global Change Biology | Year: 2010
Agricultural fields are an important anthropogenic source of atmospheric nitrous oxide (N2O) and nitric oxide (NO). Although many field studies have tested the effectiveness of possible mitigation options on N2O and NO emissions, the effectiveness of each option varies across sites due to environmental factors and field management. To combine these results and evaluate the overall effectiveness of enhanced-efficiency fertilizers [i.e., nitrification inhibitors (NIs), polymer-coated fertilizers (PCFs), and urease inhibitors (UIs)] on N2O and NO emissions, we performed a meta-analysis using field experiment data (113 datasets from 35 studies) published in peer-reviewed journals through 2008. The results indicated that NIs significantly reduced N2O emissions (mean: -38%, 95% confidential interval: -44% to -31%) compared with those of conventional fertilizers. PCFs also significantly reduced N2O emissions (-35%, -58% to -14%), whereas UIs were not effective in reducing N2O. NIs and PCFs also significantly reduced NO (-46%, -65% to -35%; -40%, -76% to -10%, respectively). The effectiveness of NIs was relatively consistent across the various types of inhibitors and land uses. However, the effect of PCFs showed contrasting results across soil and land-use type: they were significantly effective for imperfectly drained Gleysol grassland (-77%, -88% to -58%), but were ineffective for well-drained Andosol upland fields. Because available data for PCFs were dominated by certain regions and soil types, additional data are needed to evaluate their effectiveness more reliably. NIs were effective in reducing N2O emission from both chemical and organic fertilizers. Moreover, the consistent effect of NIs indicates that they are potent mitigation options for N2O and NO emissions. © 2009 Blackwell Publishing Ltd.
Kinraide T.B.,Appalachian Farming Systems Research Center |
Wang P.,CAS Nanjing Institute of Soil Science
Journal of Experimental Botany | Year: 2010
The electrical potentials at membrane surfaces (ψ0) strongly influence the physiological responses to ions. Ion activities at membrane surfaces may be computed from ψ0, and physiological responses to ions are better interpreted with surface activities than with bulk-phase activities. ψ0 influences the gating of ion channels and the driving force for ion fluxes across membranes. ψ0 may be computed with electrostatic models incorporating the intrinsic surface charge density of the membrane (σ0), the ion composition of the bathing medium, and ion binding to the membrane. Some of the parameter values needed for the models are well established: the equilibrium constants for ion binding were confirmed for several ions using multiple approaches, and a method is proposed for the computation of other binding constants. σ0 is less well established, although it has been estimated by several methods, including computation from the near-surface electrical potentials [zeta (ζ) potentials] measured by electrophoreses. Computation from ζ potentials yields values in the range-2mC m-2 to-8mC m-2, but other methods yield values in the range-15mC m-2 to-40mC m-2. A systematic discrepancy between measured and computed ζ potentials was noted. The preponderance of evidence supports the suitability of σ0=-30mC m-2. A proposed, fully paramatized Gouy-Chapman-Stern model appears to be suitable for the interpretation of many plant responses to the ionic environment. © 2010 The Author(s).
Jiang J.,CAS Nanjing Institute of Soil Science |
Xu R.-K.,CAS Nanjing Institute of Soil Science
Bioresource Technology | Year: 2013
When Cu(II) contaminated Ultisol was mixed with biochar derived from straw and incubated for 120. d, acid-soluble Cu(II) decreased by 0.08-0.33. mmol/kg due to the liming effect of biochar; 1.00-1.93. mmol/kg due to organic functional groups of biochar when it was added to the soil at 30. g/kg, and by 1.40-2.43. mmol/kg at 50. g/kg. The total functional groups and volatile matter (VM) were significantly related to Cu(II) immobilization (P<. 0.01), suggesting that it is functional groups in VM that are essential to Cu(II) immobilization in soil. The percentage of acid soluble Cu(II) decreased from 43.07% for the control, to 18.83-27.45% and 11.03-20.97% for the treatments with 30 and 50. g/kg of crop straw biochars added, respectively. The immobilized Cu(II) was primarily transformed to reducible and oxidizable forms. Biochar could retain Cu(II) for at least 120. d, indicating the long-term stability of biochar in Cu(II) immobilization. © 2013 Elsevier Ltd.
Cai Z.C.,CAS Nanjing Institute of Soil Science
Science China Earth Sciences | Year: 2012
Terrestrial ecosystems may act as a source or a sink for the atmospheric greenhouse gases, carbon dioxide (CO 2), methane (CH 4), and nitrous oxide (N 2O), depending on land use and management. This paper reviews the literature on carbon, CH 4, and N 2O fluxes from terrestrial ecosystems in China, and analyzes its national greenhouse gas budget. Carbon storage in biomass and soils in Chinese terrestrial ecosystems decreased in the past 300 years, due to deforestation and expansion of cultivated land, and reached a minimum in the late 1970s. Since then, carbon storage has increased at an estimated rate of 0.19 to 0.26 Pg C yr -1, mainly owing to reforestation and afforestation. CH 4 emission from natural wetlands decreased from 6.65 Tg CH 4 yr -1 in 1990 to 5.71 Tg CH 4 yr -1 in 2000 owing to the decrease in wetland area. CH 4 emission from flooded rice fields was 7. 41 Tg CH 4 yr -1. At the same time, aerobic soils took up atmospheric CH 4 at a rate of 2.56 Tg CH 4 yr -1. Nitrous oxide emission from forestlands, grasslands, and farmlands was positively correlated with precipitation at a national scale, and the emission rate was positively correlated with the CH 4 uptake rate of forestlands and grasslands (P<0. 01). Natural N 2O sources were estimated to be 419 Gg N yr -1 and anthropogenic sources (from farmlands) to be 292 to 476.3 Gg N yr -1, with a mean of 372. 6 Gg N yr -1. The integrated budget of greenhouse gasses indicates that Chinese terrestrial ecosystems act as a small net sink for global warming potential (GWP), ranging from 0.04 to 0.32 Pg CO 2-eq yr -1, in a striking contrast to terrestrial ecosystems globally, which are a source of 2.75 to 6.78 Pg CO 2-eq yr -1. The ratios of anthropogenic to natural sources of CH 4 and N 2O are much larger in Chinese terrestrial ecosystems than they are in global averages, reflecting greater human disturbance of terrestrial ecosystems in China. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.
Wu Y.,CAS Nanjing Institute of Soil Science |
Li T.,CAS Nanjing Institute of Soil Science |
Yang L.,CAS Nanjing Institute of Soil Science
Bioresource Technology | Year: 2012
With the public's enhanced awareness of eco-safety, environmentally benign measures based on microorganisms and microbial aggregates have become more accepted as methods of removing pollutants from aquatic systems. In this review, the application of microorganisms and microbial aggregates for removing pollutants from aqueous solutions is introduced and described based on mechanisms such as assimilation, adsorption, and biodegradation. The advantages of and future studies regarding the use of microorganisms and microbial aggregates to remove pollutants are discussed. Due to the limitation of a single microorganism species in adapting to heterogeneous conditions, this review demonstrates that the application of microbial aggregates consisting of multiple photoautotrophic and heterotrophic microorganisms, is a promising method of removing multiple pollutants from complex wastewaters and warrants further research. © 2011 Elsevier Ltd.
Peng X.,CAS Nanjing Institute of Soil Science |
Horn R.,Institute of Plant Nutrition and Soil Science
Soil Science Society of America Journal | Year: 2013
A typical soil shrinkage curve is S-shaped and composed of four phases termed structural, proportional, residual, and zero shrinkage. However, many studies have not found all four soil shrinkage phases despite investigating the full spectrum of soil moisture content. The objectives of this paper were to determine different soil shrinkage types based on the presence of shrinkage phases and to define relationships between the parameters of different shrinkage types and soil properties. A total of 270 sets of shrinkage data were collected from published (N = 245) and our unpublished work (N = 25), covering a wide range of soil types, sample sizes, and measurement methods. According to the presence of different shrinkage phases, six types of soil shrinkage curves were classified using the shrinkage model proposed by Peng and Horn (2005). Soil shrinkage types generally depended on soil structure, but not on the measurement method. The coefficient of linear extensibility (COLE) had a positive relation with saturated soil bulk density (r = 0.50, P < 0.001), clay content (r = 0.20, P < 0.05), and soil organic carbon (SOC) content (r = 0.46, P < 0.001). This paper is the first to propose six soil shrinkage types that will improve our understanding of the relationship between soil structure and soil water content. Copyright © 2013 by the Soil Science Society of America, Inc.
Lu L.,CAS Nanjing Institute of Soil Science |
Lu L.,University of Chinese Academy of Sciences |
Jia Z.,CAS Nanjing Institute of Soil Science
Environmental Microbiology | Year: 2013
The metabolic traits of ammonia-oxidizing archaea (AOA) and bacteria (AOB) interacting with their environment determine the nitrogen cycle at the global scale. Ureolytic metabolism has long been proposed as a mechanism for AOB to cope with substrate paucity in acid soil, but it remains unclear whether urea hydrolysis could afford AOA greater ecological advantages. By combining DNA-based stable isotope probing (SIP) and high-throughput pyrosequencing, here we show that autotrophic ammonia oxidation in two acid soils was predominately driven by AOA that contain ureC genes encoding the alpha subunit of a putative archaeal urease. In urea-amended SIP microcosms of forest soil (pH5.40) and tea orchard soil (pH3.75), nitrification activity was stimulated significantly by urea fertilization when compared with water-amended soils in which nitrification resulted solely from the oxidation of ammonia generated through mineralization of soil organic nitrogen. The stimulated activity was paralleled by changes in abundance and composition of archaeal amoA genes. Time-course incubations indicated that archaeal amoA genes were increasingly labelled by 13CO2 in both microcosms amended with water and urea. Pyrosequencing revealed that archaeal populations were labelled to a much greater extent in soils amended with urea than water. Furthermore, archaeal ureC genes were successfully amplified in the 13C-DNA, and acetylene inhibition suggests that autotrophic growth of urease-containing AOA depended on energy generation through ammonia oxidation. The sequences of AOB were not detected, and active AOA were affiliated with the marine Group 1.1a-associated lineage. The results suggest that ureolytic N metabolism could afford AOA greater advantages for autotrophic ammonia oxidation in acid soil, but the mechanism of how urea activates AOA cells remains unclear. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.
Shan J.,CAS Nanjing Institute of Soil Science |
Yan X.,CAS Nanjing Institute of Soil Science
Atmospheric Environment | Year: 2013
Crop residue returning is a common practice in agricultural system that consequently influences nitrous oxide (N2O) emissions. Much attention has been focused on the effects of crop residue on N2O release. However, no systematic result has yet been drawn because environmental factors among different studies vary. A meta-analysis was described to integrate 112 scientific assessments of crop residue returning on N2O emissions in this study. Results showed that crop residue returning, when averaged across all studies, had no statistically significant effect on N2O release compared with control treatments. However, the range of effects of crop residue returning on N2O emission was significantly affected by synthetic nitrogen (N) fertilizer application, type of crop residue, specific manner in which crop residue has returned, and type of land-use. N2O release was significantly inhibited by 11.7% and 27.1% (P < 0.05) when crop residue was with synthetic N fertilizer and when type of land-use was paddy, respectively. While N2O emissions were significantly enhanced by 42.1% and 23.5% (P < 0.05) when crop residue was applied alone and when type of land-use was upland, respectively. N2O emissions were likewise increased when crop residue with lower C/N ratio was used, mulching of crop residue was performed, and type of land-use was fallow. Our study provides the first quantitative analysis of crop residue returning on N2O emissions, indicating that crop residue returning has no statistically significant effect on N2O release at regional scale, and underlining that the Intergovernmental Panel on Climate Change guidelines should take the opposite effects of crop residue returning on upland and paddy into account when estimating the N2O emission factor of crop residue for different land-use types. Given that most of data are dominated by certain types of crop residue and specific application methods, more field data are required to reduce uncertainty. © 2013 Elsevier Ltd.
Liang Y.,CAS Nanjing Institute of Soil Science
ISME Journal | Year: 2015
To understand soil microbial community stability and temporal turnover in response to climate change, a long-term soil transplant experiment was conducted in three agricultural experiment stations over large transects from a warm temperate zone (Fengqiu station in central China) to a subtropical zone (Yingtan station in southern China) and a cold temperate zone (Hailun station in northern China). Annual soil samples were collected from these three stations from 2005 to 2011, and microbial communities were analyzed by sequencing microbial 16S ribosomal RNA gene amplicons using Illumina MiSeq technology. Our results revealed a distinctly differential pattern of microbial communities in both northward and southward transplantations, along with an increase in microbial richness with climate cooling and a corresponding decrease with climate warming. The microbial succession rate was estimated by the slope (w value) of linear regression of a log-transformed microbial community similarity with time (time–decay relationship). Compared with the low turnover rate of microbial communities in situ (w=0.046, P<0.001), the succession rate at the community level was significantly higher in the northward transplant (w=0.058, P<0.001) and highest in the southward transplant (w=0.094, P<0.001). Climate warming lead to a faster succession rate of microbial communities as well as lower species richness and compositional changes compared with in situ and climate cooling, which may be related to the high metabolic rates and intense competition under higher temperature. This study provides new insights into the impacts of climate change on the fundamental temporal scaling of soil microbial communities and microbial phylogenetic biodiversity.The ISME Journal advance online publication, 19 May 2015; doi:10.1038/ismej.2015.78. © 2015 International Society for Microbial Ecology
CAS Nanjing Institute of Soil Science | Date: 2012-04-23
Disclosed is a method for making a controlled release fertilizer with water-based coating using a closed large numerically controlled fluidized bed and a device therefor: collecting a granular fertilizer with a suitable granule size into a barrel; sucking the same into a coating cavity by negative pressure and making the same fluid; directing a water-based coating liquid into a spray gun, then spraying the liquid onto the surface of the fertilizer granules after nebulization; collecting the impurities in the air discharged from the coating cavity by means of a cyclone separator; dehumidifying the air discharged from the cyclone separator by means of a fluidized drying tower; and then the coating is completed. The closed large numerically controlled fluidized bed coating machine has a fluidized bed coating machine main tower, a cyclone separator, a fluidized drying tower, a blower, a heater, an air compressor, a coating liquid inlet system and a control system, and is characterized in that it has a closed air circulation system, and is provided with a dehumidifying mechanism and a water condensing mechanism for the fluidized drying tower. The present invention can reduce energy consumption, increase heating efficiency and has moisture-absorbing function; it can prevent the spray gun from blocking; it has the function of automatic feeding, which improves the efficiency of coating; therefore it is important for the achievement of a water-based coating process.