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1.
Aims
A pot study spanning four consecutive crop seasons was conducted to compare the effects of successive rice straw biochar/rice straw amendments on C sequestration and soil fertility in rice/wheat rotated paddy soil.Methods
We adopted 4.5 t ha?1, 9.0 t ha?1 biochar and 3.75 t ha?1 straw for each crop season with an identical dose of NPK fertilizers.Results
We found no major losses of biochar-C over the 2-year experimental period. Obvious reductions in CH4 emission were observed from rice seasons under the biochar application, despite the fact that the biochar brought more C into the soil than the straw. N2O emissions with biochar were similar to the controls without additives over the 2-year experimental period. Biochar application had positive effects on crop growth, along with positive effects on nutrient (N, P, K, Ca and Mg) uptake by crop plants and the availability of soil P, K, Ca and Mg. High levels of biochar application over the course of the crop rotation suppressed NH3 volatilization in the rice season, but stimulated it in the wheat season.Conclusions
Converting straw to biochar followed by successive application to soil is viable for soil C sequestration, CH4 mitigation, improvements of soil and crop productivity. Biochar soil amendment influences NH3 volatilization differently in the flooded rice and upland wheat seasons, respectively. 相似文献2.
Effect of biochar amendment on maize yield and greenhouse gas emissions from a soil organic carbon poor calcareous loamy soil from Central China Plain 总被引:30,自引:0,他引:30
Afeng Zhang Yuming Liu Genxing Pan Qaiser Hussain Lianqing Li Jinwei Zheng Xuhui Zhang 《Plant and Soil》2012,351(1-2):263-275
Aims
A field experiment was conducted to investigate the effect of biochar on maize yield and greenhouse gases (GHGs) in a calcareous loamy soil poor in organic carbon from Henan, central great plain, China.Methods
Biochar was applied at rates of 0, 20 and 40?t?ha?1 with or without N fertilization. With N fertilization, urea was applied at 300?kg?N ha?1, of which 60% was applied as basal fertilizer and 40% as supplementary fertilizer during crop growth. Soil emissions of CO2, CH4 and N2O were monitored using closed chambers at 7?days intervals throughout the whole maize growing season (WMGS).Results
Biochar amendments significantly increased maize production but decreased GHGs. Maize yield was increased by 15.8% and 7.3% without N fertilization, and by 8.8% and 12.1% with N fertilization under biochar amendment at 20?t?ha?1 and 40?t?ha?1, respectively. Total N2O emission was decreased by 10.7% and by 41.8% under biochar amendment at 20?t?ha?1 and 40?t?ha?1 compared to no biochar amendment with N fertilization. The high rate of biochar (40?t?ha?1) increased the total CO2 emission by 12% without N fertilization. Overall, biochar amendments of 20?t?ha?1 and 40?t?ha?1 decreased the total global warming potential (GWP) of CH4 and N2O by 9.8% and by 41.5% without N fertilization, and by 23.8% and 47.6% with N fertilization, respectively. Biochar amendments also decreased soil bulk density and increased soil total N contents but had no effect on soil mineral N.Conclusions
These results suggest that application of biochar to calcareous and infertile dry croplands poor in soil organic carbon will enhance crop productivity and reduce GHGs emissions. 相似文献3.
Biochar’s role as an alternative N-fertilizer: ammonia capture 总被引:17,自引:0,他引:17
Background
Biochar’s role as a carbon sequestration agent, while simultaneously providing soil fertility improvements when used as an amendment, has been receiving significant attention across all sectors of society, ranging from academia, industry, government, as well as the general public. This has lead to some exaggeration and possible confusion regarding biochar’s actual effectiveness as a soil amendment. One sparsely explored area where biochar appears to have real potential for significant impact is the soil nitrogen cycle.Scope
Taghizadeh-Toosi et al. (this issue) examined ammonia sorption on biochar as a means of providing a nitrogen-enriched soil amendment. The longevity of the trapped ammonia was particularly remarkable; it was sequestered in a stable form for at least 12?days under laboratory air flow. Furthermore, the authors observed increased 15N uptake by plants grown in soil amended with the 15N-enriched biochar, indicating that the 15N was not irreversibly bound, but, was plant-available.Conclusions
Their observations add credence to utilizing biochar as a carrier for nitrogen fertilization, while potentially reducing the undesired environmental consequences through gas emissions, overland flow, and leaching. 相似文献4.
Nitrogen dynamics following field application of biochar in a temperate North American maize-based production system 总被引:5,自引:0,他引:5
David Güereña Johannes Lehmann Kelly Hanley Akio Enders Charles Hyland Susan Riha 《Plant and Soil》2013,365(1-2):239-254
Background and aims
Biochar additions to tropical soils have been shown to reduce N leaching and increase N use efficiency. No studies exist verifying reduced N leaching in field experiments on temperate agricultural soils or identifying the mechanism for N retention.Methods
Biochar derived from maize stover was applied to a maize cropping system in central New York State at rates of 0, 1, 3, 12, and 30 t?ha-1 in 2007. Secondary N fertilizer was added at 100, 90, 70, and 50 % of the recommended rate (108 kg N ha-1). Nitrogen fertilizer enriched with 15?N was applied in 2009 to the 0 and 12 t?ha-1 of biochar at 100 and 50 % secondary N application.Results
Maize yield and plant N uptake did not change with biochar additions (p?>?0.05; n?=?3). Less N (by 82 %; p?<?0.05) was lost after biochar application through leaching only at 100 %?N fertilization. The reason for an observed 140 % greater retention of applied 15?N in the topsoil may have been the incorporation of added 15?N into microbial biomass which increased approximately three-fold which warrants further research. The low leaching of applied fertilizer 15?N (0.42 % of applied N; p?<?0.05) and comparatively high recovery of applied 15?N in the soil (39 %) after biochar additions after one cropping season may also indicate greater overall N retention through lower gaseous or erosion N losses with biochar.Conclusions
Addition of biochar to fertile soil in a temperate climate did not improve crop growth or N use efficiency, but increased retention of fertilizer N in the topsoil. 相似文献5.
Arezoo Taghizadeh-Toosi Tim J. Clough Robert R. Sherlock Leo M. Condron 《Plant and Soil》2012,353(1-2):73-84
Aims
Ammonia (NH3) can be volatilised from the soil surface following the surface application of nitrogenous fertilisers or ruminant urine deposition. The volatilisation of NH3 is of agronomic and environmental concern, since NH3-N is a form of reactive nitrogen. Ammonia adsorption onto biochar has the potential to mitigate NH3 losses, but to date no studies have examined the potential for reducing NH3 losses when biochar is present in the soil matrix.Methods
We used 15N-enriched urine to examine the effect of incorporating a wood based low-temperature biochar into soil on NH3 volatilisation. Then, we extracted the urine-treated biochar and compared its potential to act as a plant N source with fresh biochar, while growing ryegrass (Lolium perenne).Results
The NH3 volatilisation from 15N-labelled ruminant urine, applied to soil, was reduced by 45% after incorporating either 15 or 30?t ha?1 of biochar. When the urine-treated biochar particles were transferred into fresh soil, subsequent plant growth was not affected but the uptake of 15N in plant tissues increased, indicating that the adsorbed-N was plant available.Conclusions
Our results show that incorporating biochar into the soil can significantly decrease NH3 volatilisation from ruminant urine and that the NH3-N adsorbed onto the biochar is bioavailable. Further studies are now required to assess the temporal dynamics of the N pools involved. 相似文献6.
Jiaojiao Zhang Yongfu Li Scott X. Chang Peikun Jiang Guomo Zhou Juan Liu Jiasen Wu Zhenming Shen 《Plant and Soil》2014,376(1-2):363-375
Background and aims
The impact of understory vegetation control or replacement with selected plant species, which are common forest plantation management practices, on soil C pool and greenhouse gas (GHG, including CO2, CH4 and N2O) emissions are poorly understood. The objective of this paper was to investigate the effects of understory vegetation management on the dynamics of soil GHG emissions and labile C pools in an intensively managed Chinese chestnut (Castanea mollissima Blume) plantation in subtropical China.Methods
A 12-month field experiment was conducted to study the dynamics of soil labile C pools and GHG emissions in a Chinese chestnut plantation under four different understory management practices: control (Control), understory removal (UR), replacement of understory vegetation with Medicago sativa L. (MS), and replacement with Lolium perenne L. (LP). Soil GHG emissions were determined using the static chamber/GC technique.Results
Understory management did not change the seasonal pattern of soil GHG emissions; however, as compared with the Control, the UR treatment increased soil CO2 and N2O emissions and CH4 uptake, and the MS and LP treatments increased CO2 and N2O emissions and reduced CH4 uptake (P?<?0.05 for all treatment effects, same below). The total global warming potential (GWP) of GHG emissions in the Control, UR, MS, and LP treatments were 36.56, 39.40, 42.36, and 42.99 Mg CO2 equivalent (CO2-e) ha?1 year?1, respectively, with CO2 emission accounting for more than 95 % of total GWP regardless of the understory management treatment. The MS and LP treatments increased soil organic C (SOC), total N (TN), soil water soluble organic C (WSOC) and microbial biomass C (MBC), while the UR treatment decreased SOC, TN and NO3 ?-N but had no effect on WSOC and MBC. Soil GHG emissions were correlated with soil temperature and WSOC across the treatments, but had no relationship with soil moisture content and MBC.Conclusions
Although replacing competitive understory vegetation with legume or less competitive non-legume species increased soil GHG emissions and total GWP, such treatments also increased soil C and N pools and are therefore beneficial for increasing soil C storage, maintaining soil fertility, and enhancing the productivity of Chinese chestnut plantations. 相似文献7.
Assessment of carbon sustainability under different tillage systems in a double rice cropping system in Southern China 总被引:1,自引:0,他引:1
Jian-Fu Xue Sheng-Li Liu Zhong-Du Chen Fu Chen Rattan Lal Hai-Ming Tang Hai-Lin Zhang 《The International Journal of Life Cycle Assessment》2014,19(9):1581-1592
Purpose
Adoption of the carbon (C)-friendly and cleaner technology is an effective solution to offset some of the anthropogenic emissions. Conservation tillage is widely considered as an important sustainable technology and for the development of conservation agriculture (CA). Thus, the objective of this study was to assess the C sustainability of different tillage systems in a double rice (Oryza sativa L.) cropping system in southern China.Methods
The experiment was established with no-till (NT), rotary tillage (RT), and conventional tillage (CT) treatments since 2005. Emission of greenhouse gasses (GHG), C footprint (CF), and ecosystem service through C sequestration in different tillage systems were compared.Result and discussion
Emission of GHG from agricultural inputs (Mg CO2-eq ha?1 year?1) ranged from 1.81 to 1.97 for the early rice, 1.82 to 1.98 for the late rice, and 3.63 to 3.95 for the whole growing season, respectively. The CF (kg CO2-eq kg?1 of rice year?1) in the whole growing seasons were 1.27, 1.85, and 1.40 [excluding soil organic carbon (SOC) storage] and 0.54, 1.20, and 0.72 (including SOC storage) for NT, RT, and CT, respectively. The value of ecosystem services on C sequestration for the whole growing seasons ranged from ¥3,353 to 4,948 ha?1 year?1 and followed the order of NT > CT > RT. The C sustainability under NT was better than that under RT for the late, but reversed for the early rice. However, NT system had better C sustainability for the whole cropping system compared with CT.Conclusions
Therefore, NT is a preferred technology to reduce GHG emissions, increase ecosystem service functions of C sequestration, and improve C sustainability in a double rice cropping region of Southern China. 相似文献8.
Woody biochar's greenhouse gas mitigation potential across fertilized and unfertilized agricultural soils and soil moisture regimes 下载免费PDF全文
Biochar has been widely researched as an important technology for climate smart agriculture, yet work is still necessary to identify the magnitude of potential greenhouse gas (GHG) mitigation and mechanisms involved. This study measured slow‐pyrolysis wood‐derived biochar's impact on GHG efflux, mineral N dynamics, and soil organic C in a series of two incubations across fertilized and unfertilized agricultural soils and soil moisture regimes. This research explored the magnitude of biochar's full GHG mitigation potential and drivers of such impacts. Results of this incubation indicate slow‐pyrolysis wood‐derived biochar has potential to provide annual emission reductions of 0.58–1.72 Mg CO2‐eq ha?1 at a 25 Mg ha?1 biochar application rate. The greatest GHG mitigation potential was from C sequestration and nitrous oxide (N2O) reduction in mineral N fertilized soils, with minimal impacts on N2O emissions in unfertilized soils, carbon dioxide (CO2) emissions, and methane (CH4) uptake. Analysis of mineral N dynamics in the bulk soil and on biochar isolates indicated that neither biochar impacts on net mineralization and nitrification nor retention of ammonium () on biochar isolates could explain biochar's N2O reduction. Instead, biochar amendments exhibited consistent N2O emission reductions relative to the N2O emission in the control soil regardless of soil type and fertilization. Results across a soil moisture gradient suggest that woody biochar may aerate soils shifting redox conditions and subsequent N2O production. Understanding the magnitude of biochar's GHG reduction potential and the mechanisms driving these effects can help inform biochar modeling efforts, explain field results and identify agricultural applications that maximize biochar's full GHG mitigation potential. 相似文献
9.
Impacts of greenwaste biochar on ammonia volatilisation from bauxite processing residue sand 总被引:7,自引:0,他引:7
C. R. Chen I. R. Phillips L. M. Condron J. Goloran Z. H. Xu K. Y. Chan 《Plant and Soil》2013,367(1-2):301-312
Background and Aims
The objective of this study was to test the suitability of greenwaste biochar to aid nitrogen (N) retention in rehabilitated bauxite-processing residue sand (BRS).Methods
Bauxite residue sand was collected from the Alcoa of Australia Pinjarra refinery. The pH of BRS was adjusted to values of 5, 7, 8 and 9 and subsequently amended with different rates (1, 5, 10 and 20 %, w/w) of greenwaste biochar. The loss of N via NH3 volatilization following addition of di-ammonium phosphate (DAP) was determined using an acid trapping method.Results
At low pH (5), increasing pH rather than adsorption capacity, resulting from biochar addition, caused greater losses of N through volatilization from BRS. In BRS with medium pH (7, 8), increasing adsorption capacity, induced by biochar addition, played the more dominant role in enhancing adsorption of NH 4 + -N /NH3-N and lowering NH3 volatilization. In the BRS with high pH (9), the majority of NH 4 + -N /NH3-N pools was lost via NH3 volatilization due to the strong acid-base reaction at this pH.Conclusions
It is concluded that the interaction of changes in pH and adsorption capacity induced by greenwaste biochar addition affects the availability and dynamics of NH 4 + -N/ NH3-N in BRS amended with DAP. 相似文献10.
Greenhouse gas emissions from forestry in East Norway 总被引:1,自引:0,他引:1
Volkmar Timmermann Janka Dibdiakova 《The International Journal of Life Cycle Assessment》2014,19(9):1593-1606
Purpose
So far no calculations have been made for greenhouse gas (GHG) emissions from forestry in East Norway. This region stands for 80 % of the Norwegian timber production. The aim of this study was to assess the annual GHG emissions of Norwegian forestry in the eastern parts of the country from seed production to final felling and transport of timber to sawmill and wood processing industry (cradle-to-gate inventory), based on specific Norwegian data.Methods
The life cycle inventory was conducted with SimaPro applying primary and secondary data from Norwegian forestry. GHG emissions of fossil-related inputs from the technosphere were calculated for the functional unit of 1 m3 timber extracted and delivered to industry gate in East Norway in 2010. The analysis includes seed and seedling production, silvicultural operations, forest road construction and upgrading, thinning, final felling, timber forwarding and timber transport on road and rail from the forest to the industry. Norwegian time studies of forestry machines and operations were used to calculate efficiency, fuel consumption and transport distances. Due to the lack of specific Norwegian data in Ecoinvent, we designed and constructed unit processes based on primary and secondary data from forestry in East Norway.Results and discussion
GHG emissions from forestry in East Norway amounted to 17.893 kg CO2-equivalents per m3 of timber delivered to industry gate in 2010. Road transport of timber accounted for almost half of the total GHG emissions, final felling and forwarding for nearly one third of the GHG emissions. Due to longer road transport distances, pulpwood had higher impact on the climate change category than saw timber. The construction of forest roads had the highest impact on the natural land transformation category. The net CO2 emissions of fossil CO2 corresponded to 2.3 % of the CO2 sequestered by 1 m3 of growing forest trees and were compared to a calculation of biogenic CO2 release from the forest floor as a direct consequence of harvesting.Conclusions
Shorter forwarding and road transport distances, increased logging truck size and higher proportion of railway transport may result in lower emissions per volume of transported timber. A life cycle assessment of forestry may also consider impacts on environmental categories other than climate change. Biogenic CO2 emissions from the soil may be up to 10 times higher than the fossil-related emissions, at least in a short-term perspective, and are highly dependent on stand rotation length. 相似文献11.
Background and aims
Biochar is produced from the pyrolysis of organic materials, and when buried in soil can act as a long term soil carbon (C) store. Evidence suggests that biochar can also increase crop yields, reduce nutrient leaching and increase biological nitrogen fixation in leguminous plants. However, the potential for increasing biological N2 fixation in agroecosystems is poorly understood, with inconsistent reports of root nodulation following biochar application. Therefore, the aim of this study was to determine the effect of biochar application rate and time since application on nodulation and nitrogenase activity in nodules of clover grown in a temperate agricultural soil.Methods
We used replicated field plots with three biochar application rates (0, 25 and 50 t ha?1). Three years after biochar amendment, the plots were further split and fresh biochar added at two different rates (25 and 50 t ha?1) resulting in double-loaded reapplications of 25?+?25 and 50?+?50 t ha?1.Results
Three years after biochar application, there was no significant difference in the total number of root nodules between biochar-amended and unamended soil, regardless of the application rate. However, despite clover root nodules being of a similar number and size the level of nitrogenase activity of individual nodules in biochar-amended soil was significantly higher than in unamended soil. Reapplication of biochar resulted in decreased nodulation, although the rate of nitrogenase activity per nodule remained unaffected.Conclusion
In the short term, biochar influences root nodule number and localised N2 fixation per nodule; however, total nitrogenase activity for the whole root system remained unaffected by the application rate of biochar or time since its application. These results emphasise the importance of long-term field studies, with a variety of applications rates for determining the influence of biochar applications on N2-fixing organisms and in providing data that can meaningfully inform agronomic management decisions and climate change mitigation strategies. 相似文献12.
Liebig’s law of the minimum applied to a greenhouse gas: alleviation of P-limitation reduces soil N2O emission 总被引:2,自引:0,他引:2
Background and aims
Emission of the greenhouse gas (GHG) nitrous oxide (N2O) are strongly affected by nitrogen (N) fertilizer application rates. However, the role of other nutrients through stoichiometric relations with N has hardly been studied. We tested whether phosphorus (P) availability affects N2O emission. We hypothesized that alleviation of plant P-limitation reduces N2O emission through lowering soil mineral N concentrations.Methods
We tested our hypothesis in a pot experiment with maize (Zea mays L.) growing on a P-limiting soil/sand mixture. Treatment factors included P and N fertilization and inoculation with Arbuscular Mycorrhizal Fungi (AMF; which can increase P uptake).Results
Both N and P fertilization, as well as their interaction significantly (P?<?0.01) affected N2O emission. Highest N2O emissions (2.38 kg N2O-N ha?1) were measured at highest N application rates without P fertilization or AMF. At the highest N application rate, N2O fluxes were lowest (0.71 kg N2O-N ha?1) with both P fertilization and AMF. The N2O emission factors decreased with 50 % when P fertilization was applied.Conclusions
Our results illustrate the importance of the judicious use of all nutrients to minimize N2O emission, and thereby further underline the intimate link between sound agronomic practice and prudent soil GHG management. 相似文献13.
Aims
Decomposition of leaf litterfall plays a major role for nitrogen (N) dynamics in soils. However, little is known as to which extent beech leaf litter contributes to N turnover and nitrous oxide (N2O) emissions within one decade after litterfall.Methods
In 1997, we exchanged recently fallen leaf litter by 15N-labelled litter in a beech stand (Fagus sylvatica) at the Solling, Germany. Measurements were conducted 2–3 and 10–11 years after litter exchange.Results
Two years after litter exchange, 92 % of added 15N was recovered in the surface 10 cm of the soil. The labelled N was primarily found in the upper part of the F layer of the moder type humus. Eleven years after litter exchange, 73 % of the added 15N was lost and the remaining 27 % was mainly recovered in the lower part of the F layer indicating N sequestration. The remaining leaf litter N was subject to measurable N mineralisation (2–3 % of litter N) and N2O production (0.02 %). Between 0.3 % (eleventh year) and 0.6 % (second year) of total annual N2O emissions were attributed to beech leaf litter of a single year.Conclusions
Most of the annual N2O emissions (1.33–1.54 kg N ha?1 yr?1) were probably derived from older soil N pools. 相似文献14.
Background and aims
Combination of rewetting and wetland crop cultivation (paludiculture) is pursued as a wider carbon dioxide (CO2) mitigation option in drained peatland. However, information on the overall greenhouse gas (GHG) balance for paludiculture is lacking. We investigated the GHG balance of peatlands grown with reed canary grass (RCG) and rewetted to various extents.Methods
Gas fluxes of CO2, methane (CH4) and nitrous oxide (N2O) were measured with a static chamber technique for 10 months from mesocosms sown with RCG and manipulated to ground water levels (GWL) of 0, ?10, ?20, ?30 and ?40 cm below the soil surface. Gross primary production (GPP) was estimated from the above ground biomass yield.Results
The mean dry biomass yield across all water table treatments was 6 Mg ha?1 with no significant differences between the treatments. Raising the GWL to the surface decreased both the net ecosystem exchange (NEE) of CO2 and N2O emissions whereas CH4 emissions increased. Total cumulative GHG emissions (for 10 months) corresponded to 0.08, 0.13, 0.61, 0.68 and 0.98 kg CO2 equivalents m?2 from the GWL treatments at 0, ?10, ?20, ?30 and ?40 cm below the soil surface, respectively.Conclusions
The results showed that a reduction in total GHG emission can be achieved without losing the productivity of newly established RCG when GWL is maintained close to the surface. Further studies should address the practical constrains and long-term productivity of RCG cultivation in rewetted peatlands. 相似文献15.
Proof of concept: nitrogen use efficiency of contrasting spring wheat varieties grown in greenhouse and field 总被引:1,自引:0,他引:1
Aims
Major aims were to test and evaluate a new concept for assessment of nitrogen use efficiency (NUE) of crops by growing six spring wheat varieties in greenhouse and field environments. NUE was calculated with a plant based concept integrating the entire crop life history and separating plant characteristics from environmental factors affecting NUE. Specific hypotheses were tested related to the varieties’ drought and nutrient fertilisation responses for NUE components, and coherence of those responses in field and greenhouse.Methods
The wheat (Triticum aestivum L.) cultivated varieties ‘Diskett’, ‘Granary’, ‘Quarna’, ‘Stilett’, ‘Vinjett’, and a Swedish landrace (‘Dala’) were grown in field and greenhouse environments in Central Sweden. Two fertilisation treatments were included in a field and greenhouse experiment, and in the greenhouse also drought. The NUE components N uptake efficiency (UN), grain-specific N efficiency (EN,g) and grain N concentration (CN,g) were assessed.Results
Drought reduced yield and NUE through EN,g, and more so when drought occurred prior to anthesis than after anthesis. Effect of fertilisation treatment on NUE components was similar in the two set-ups, but there were fewer variety × fertilisation interactions in the field. UN was higher in the field and EN,g was higher in the greenhouse, while CN,g and overall NUE were similar in the two environments. Ranking of varieties regarding NUE and UN was similar in the greenhouse and field, but different regarding EN,g and CN,g.Conclusions
The NUE concept is a useful tool to describe and integrate important NUE components for crops grown in different treatments (nutrient fertilisation, drought) and experimental set-ups, i.e. greenhouse and field. Similar variety ranking in overall NUE across experimental set-ups indicates stable results in different environments. 相似文献16.
Arbuscular mycorrhizas and their role in plant growth, nitrogen interception and soil gas efflux in an organic production system 总被引:2,自引:0,他引:2
Background and aims
Roots and mycorrhizas play an important role in not only plant nutrient acquisition, but also ecosystem nutrient cycling.Methods
A field experiment was undertaken in which the role of arbuscular mycorrhizas (AM) in the growth and nutrient acquisition of tomato plants was investigated. A mycorrhiza defective mutant of tomato (Solanum lycopersicum L.) (named rmc) and its mycorrhizal wild type progenitor (named 76R) were used to control for the formation of AM. The role of roots and AM in soil N cycling was studied by injecting a 15N-labelled nitrate solution into surface soil at different distances from the 76R and rmc genotypes of tomato, or in plant free soil. The impacts of mycorrhizal and non-mycorrhizal root systems on soil greenhouse gas (CO2 and 14+15N2O and 15N2O) emissions, relative to root free soils, were also studied.Results
The formation of AM significantly enhanced plant growth and nutrient acquisition, including interception of recently applied NO 3 ? . Whereas roots caused a small but significant decrease in 15N2O emissions from soils at 23?h after labeling, compared to the root-free treatment, arbuscular mycorrhizal fungi (AMF) had little effect on N2O emissions. In contrast soil CO2 emissions were higher in plots containing mycorrhizal root systems, where root biomass was also greater.Conclusions
Taken together, these data indicate that roots and AMF have an important role to play in plant nutrient acquisition and ecosystem N cycling. 相似文献17.
Biochar may affect the root morphology and nitrogen (N) use efficiency
(NUE) of rice at seedling stage, which has not been clearly verified until now. To
clarify it, we conducted a pot experiment regarding to two soil types (Hydragric
Anthrosol and Haplic Acrisol), two biochar application rates (0.5 wt% and 1.5 wt
%) and two rice varieties (common rice var. Xiushui134 and hybrid super rice var.
Zhongkejiayou12-6) meanwhile. Seedling NUE of common rice Xiuhui134 was
significantly increased (p < 0.05) by 78.2% in Hydragric Anthrosol and by
91.4% in Haplic Acrisol following biochar addition with 1.5 wt%. However, biochar addition exerted no influence on seedling NUE of super rice Zhongkejiayou12-6 in both soils. Overall, 0.09–0.10 units higher soil pH and 105–
116% higher soil NH4+
-N were observed in Xiushui134 growing two soils with
1.5 wt% biochar. In addition, improved root morphology (including longer root
length, larger root surface area, bigger root volume, and more root tips) contributed to the higher seedling NUE of Xiushui134 in two soils. The soil pH and
NH4+
-N content, also the root morphology were influenced by biochar, which
though could not thoroughly explained the NUE of Zhongkejiayou12-6. In conclusion, biochar application to paddy soil changed soil pH and NH4+
-N content,
root growth, and the consequent seedling NUE of rice, which effects are relative
with rice cultivar, biochar addition rate, and soil type. 相似文献
18.
Daeseung Kyung Dongwook Kim Sora Yi Wonyong Choi Woojin Lee 《The International Journal of Life Cycle Assessment》2017,22(12):1901-1911
Purpose
The aim of this study was to estimate the total greenhouse gas (GHG) emissions generated from whole life cycle stages of a sewer pipeline system and suggest the strategies to mitigate GHG emissions from the system.Methods
The process-based life cycle assessment (LCA) with a city-scale inventory database of a sewer pipeline system was conducted. The GHG emissions (direct, indirect, and embodied) generated from a sewer pipeline system in Daejeon Metropolitan City (DMC), South Korea, were estimated for a case study. The potential improvement actions which can mitigate GHG emissions were evaluated through a scenario analysis based on a sensitivity analysis.Results and discussion
The amount of GHG emissions varied with the size (150, 300, 450, 700, and 900 mm) and materials (polyvinyl chloride (PVC), polyethylene (PE), concrete, and cast iron) of the pipeline. Pipes with smaller diameter emitted less GHG, and the concrete pipe generated lower amount of GHG than pipes made from other materials. The case study demonstrated that the operation (OP) stage (3.67 × 104 t CO2eq year?1, 64.9%) is the most significant for total GHG emissions (5.65 × 104 t CO2eq year?1) because a huge amount of CH4 (3.51 × 104 t CO2eq year?1) can be generated at the stage due to biofilm reaction in the inner surface of pipeline. Mitigation of CH4 emissions by reducing hydraulic retention time (HRT), optimizing surface area-to-volume (A/V) ratio of pipes, and lowering biofilm reaction during the OP stage could be effective ways to reduce total GHG emissions from the sewer pipeline system. For the rehabilitation of sewer pipeline system in DMC, the use of small diameter pipe, combination of pipe materials, and periodic maintenance activities are suggested as suitable strategies that could mitigate GHG emissions.Conclusions
This study demonstrated the usability and appropriateness of the process-based LCA providing effective GHG mitigation strategies at a city-scale sewer pipeline system. The results obtained from this study could be applied to the development of comprehensive models which can precisely estimate all GHG emissions generated from sewer pipeline and other urban environmental systems.19.
Satoshi Ogawa Michael Gomez Selvaraj Angela Joseph Fernando Mathias Lorieux Manabu Ishitani Susan McCouch Juan David Arbelaez 《Plant and Soil》2014,375(1-2):303-315
Aims
In rice, seminal root elongation plays an important role in acquisition of nutrients such as N and P, but the extent to which different N forms and P concentrations affect root growth is poorly understood. This study aimed to examine N- and P-mediated seminal root elongation response and to identify putative QTLs associated with seminal root elongation.Methods
Seminal root elongation was evaluated in 15 diverse wild and cultivated accessions of rice, along with 48 chromosome segment substitution lines (CSSLs) derived from a cross between the rice variety ‘Curinga’ and Oryza rufipogon (IRGC 105491). Root elongation in response to different forms of N (NH4 +, NO3 ? and NH4NO3) and concentrations of P was evaluated under hydroponic conditions, and associated putative QTL regions were identified.Results
The CSSL parents had contrasting root responses to N and P. Root elongation in O. rufipogon was insensitive to N source and concentration, whereas Curinga was responsive. In contrast to N, seminal root elongation and P concentration was positively correlated. Three putative QTLs for seminal root elongation in response to N were detected on chromosome 1, and one QTL on chromosome 3 was associated with low P concentration.Conclusions
Genetic variation in seminal root elongation and plasticity of nutrient response may be appropriate targets for marker-assisted selection to improve rice nutrient acquisition efficiency. 相似文献20.
Effects of biochar amendment on root traits and contaminant availability of maize plants in a copper and arsenic impacted soil 总被引:1,自引:0,他引:1
Aoife Brennan Eduardo Moreno Jiménez Markus Puschenreiter José Antonio Alburquerque Christine Switzer 《Plant and Soil》2014,379(1-2):351-360