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1.
Neil A. Hipps Michael J. Davies Joel M. Dunn Howard Griffiths Christopher J. Atkinson 《Plant and Soil》2014,375(1-2):61-74
Aims
The objectives were to investigate (i) the forms and release pattern of P from an ash-rich biochar-amended sandy soil; (ii) the transformation of biochar P in a soil-plant system.Methods
Several methodologies (a bioassay test, soluble P extractions, a sequential P fractionation and successive P extractions via resin strips) were used to study the bioavailability and transformation of P in a sandy soil fertilised with either conventional P fertilisers [Ca(H2PO4)2 (CaP) and Sechura phosphate rock (SPR)] or biochars produced from cattle manure (MAe) and alum-treated biosolids (BSe) at four temperatures (250, 350, 450, and 550 °C).Results
Biochar P mainly contributed to increase soil resin-extractable P- and inorganic NaOH-extractable P-fractions, and thus to plant available P. The decrease in P concentrations of those fractions was caused by the uptake of P by plants rather than their transformations into more stable forms. P release rates diminished following the order: CaP > MAe > BSe > SPR, which indicates a decline in P availability from these P sources.Conclusions
Phosphorus-rich biochar can be used as a slow-release fertiliser. It is necessary to determine available P (either soil or fertiliser tests) in biochars prior to its application to soil, so that dose, frequency and timing of application are correctly established. 相似文献2.
Degradation kinetics of biochar from pyrolysis and hydrothermal carbonization in temperate soils 总被引:2,自引:0,他引:2
Mo Bai Burkhard Wilske Franz Buegger Jürgen Esperschütz Claudia Irene Kammann Christian Eckhardt Martin Koestler Philipp Kraft Martin Bach Hans-Georg Frede Lutz Breuer 《Plant and Soil》2013,372(1-2):375-387
Background and Aims
Estimates of biochar residence times in soils range over three orders of magnitude. We present the first direct comparison between the biodegradation of a char from hydrothermal carbonization (htcBC) and pyrolysis (pyrBC) with high temporal resolution.Methods
Mineralization of the biochars and their shared Miscanthus feedstock in three soils was determined directly by the 13CO2 efflux using a novel method incorporating wavelength scanned cavity ring-down spectroscopy. Biochar half-life (t1/2) was estimated with three empirical models.Results
(1) The htcBC was readily biodegradable, whereas pyrBC was more recalcitrant. (2) Cumulative degradation of both biochars increased with soil organic carbon and nitrogen content. (3) The corrected Akaike information criterion (AICC) showed an overall preference for the double exponential model (DEM) reflecting a labile and a recalcitrant C-pool, over the first-order degradation model (FODM) and a logarithmic model. (4) The DEM resulted in t1/2 ranging from 19.7–44.5, 0.7–2.1 and 0.8–1.3 years for pyrBC, htcBC and feedstock, respectively.Conclusion
The degradation was rather similar between feedstock and htcBC but one order of magnitude slower for pyrBC. The AICC preferred FODM in two cases, where the DEM parameters indicated no distinction between a labile and recalcitrant carbon pool. 相似文献3.
Marcia DeLonge Karen L. Vandecar Paolo D’Odorico Deborah Lawrence 《Plant and Soil》2013,365(1-2):201-209
Background and Aims
Bioavailable phosphorus (P) represents a primary constraint on productivity in many ecosystems on highly-weathered soils. Soil moisture can be important to determining P bioavailability and net primary productivity in these systems. However, hydrologic controls on P availability remain poorly understood.Methods
We used “resins” (anion-exchange membranes) to quantify the response of labile P, an estimate of bioavailable P, to soil moisture conditions in two highly-weathered soils (rendzina, ultisol). The resins were either incubated in soil or shaken with a soil-water slurry.Results
Resin incubations in aerobic soil effectively quantified labile P in soils under changing moisture conditions, extracting significant amounts of labile P while avoiding the disturbance imposed by slurries. Wetting field-moist soils resulted in pulsed labile P, with lagged peaks occurring days after the largest moisture additions. Re-wetting air-dried soils enhanced labile P immediately, with the largest amounts observed at the highest moisture levels; labile P steadily declined following the moisture addition.Conclusions
Soil moisture levels and history strongly impacted labile P, indicating the importance of both variables when interpreting labile P measurements. These results also suggest that P availability is linked to both the amount and timing of rainfall, with implications for plant productivity in regions exposed to changing moisture regimes. 相似文献4.
Contrasting effects of manure and green waste biochars on the properties of an acidic ferralsol and productivity of a subtropical pasture 总被引:1,自引:0,他引:1
P. G. Slavich K. Sinclair S. G. Morris S. W. L. Kimber A. Downie L. Van Zwieten 《Plant and Soil》2013,366(1-2):213-227
Background and Aim
We hypothesised that amending an acidic ferralsol with biochar would improve the productivity of a subtropical dairy pasture via reducing soil acidity related constraints and result in improved nitrogen use efficiency. We examined two contrasting biochars with different carbon, nutrient content and acid neutralising values.Methods
Field plots were amended with one of three biochar treatments (Nil, feedlot manure biochar [FM], green waste biochar [GW]) in combination with presence or absence of NPK fertiliser and presence or absence of liming. The FM and GW biochars had a carbon content of 44 and 76 %, available phosphorous of 5,960 and 93 mg kg?1, and liming values of 13 and 5.6 %, respectively. The pasture was managed to supply year round high quality feed for dairy production.Results
The FM biochar increased total pasture productivity by 11 % and improved the agronomic nitrogen use efficiency by 23 %. It also reduced soil acidity but did not significantly affect the pH dependent soil cation exchange capacity. The GW biochar did not improve pasture productivity. Both biochars resulted in an increase in the soil carbon density.Conclusions
The high available phosphorous content of FM biochar makes it an effective amendment for acidic ferralsols. Greenwaste biochar did not have sufficient acid neutralising capacity or phosphorous content to reduce soil acidity constraints. Both biochars enhance soil carbon storage in pasture systems on ferralsol. 相似文献5.
Pretreatment of microcrystalline cellulose in organic electrolyte solutions for enzymatic hydrolysis
Background
Biomass use for the production of bioethanol or platform chemicals requires efficient breakdown of biomass to fermentable monosaccharides. Lignocellulosic feedstocks often require physicochemical pretreatment before enzymatic hydrolysis can begin. The optimal pretreatment can be different for different feedstocks, and should not lead to biomass destruction or formation of toxic products.Methods
We examined the influence of six mild sulfuric acid or water pretreatments at different temperatures on the enzymatic degradability of sugar-beet pulp (SBP).Results
We found that optimal pretreatment at 140°C of 15 minutes in water was able to solubilize 60% w/w of the total carbohydrates present, mainly pectins. More severe treatments led to the destruction of the solubilized sugars, and the subsequent production of the sugar-degradation products furfural, hydroxymethylfurfural, acetic acid and formic acid. The pretreated samples were successfully degraded enzymatically with an experimental cellulase preparation.Conclusions
In this study, we found that pretreatment of SBP greatly facilitated the subsequent enzymatic degradation within economically feasible time ranges and enzyme levels. In addition, pretreatment of SBP can be useful to fractionate functional ingredients such as arabinans and pectins from cellulose. We found that the optimal combined severity factor to enhance the enzymatic degradation of SBP was between log R'0 = -2.0 and log R'0 = -1.5. The optimal pretreatment and enzyme treatment solubilized up to 80% of all sugars present in the SBP, including ≥90% of the cellulose. 相似文献6.
Hai-kun Ma Ana Pineda Andre W. G. van der Wurff T. Martijn Bezemer 《Plant and Soil》2018,431(1-2):257-272
Aim
To investigate the effects of biochar on biological and chemical phosphorus (P) processes and identify potential interactive effects between P fertilizer and biochar on P bioavailability in the rhizosphere of maize.Methods
We conducted a pot-experiment with maize in a sandy loam soil with two fertilizer levels (0 and 100 mg P kg ?1) and three biochars produced from soft wood (SW), rice husk (RH) and oil seed rape (OSR). Sequential P fractionation was performed on biochar, bulk soil, and rhizosphere soil samples. Acid and alkaline phosphatase activity and root exudates of citrate, glucose, fructose, and sucrose in the rhizosphere were determined.Results
RH and OSR increased readily available soil P, whereas SW had no effect. However, over time available P from the biochars moved to less available P pools (Al-P and Fe-P). There were no interactive effects between P fertilizer and biochar on P bioavailability. Exudates of glucose and fructose were strongly affected by especially RH, whereas sucrose was mostly affected by P fertilizer. Alkaline phosphatase activity was positively correlated with pH, and citrate was positively correlated with readily available P.Conclusion
Biochar effects on biological and chemical P processes in the rhizosphere are driven by biochar properties.7.
Mojtaba Sankian Abdolreza Varasteh Nazanin Pazouki Mahmoud Mahmoudi 《Clinical and molecular allergy : CMA》2005,3(1):1-9
Background
The basophil activation test (BAT), in which translocation of markers to the surface of blood basophils is measured in response to allergen by flow cytometry, is a rapid assay that is gaining popularity. Two markers are currently being evaluated for the BAT; CD63 and the lineage-specific CD203c. In a recent report, detection of CD203c after lysis with Saponin was shown to be superior to detection of CD63 after lysis with formic acid. We wanted to compare a) lysis with formic acid and lysis with Saponin, b) the response through CD203c and CD63, and c) the definition 10% activated cells above background with the probability binning metric T(χ) > 4, on sets of data generated with blood basophils stimulated with varying concentrations of anti-FcεRI antibody.Methods
Blood from volunteers was incubated with serial logarithmic dilutions of anti-FcεRI and subsequently with antibodies to CD203c PE and CD63 FITC. Sets of samples set up in parallel were lysed with either Saponin based Whole Blood Lysing reagent or with formic acid based Immunoprep/Q-prep. Samples were acquired on a FACS Calibur, but were compensated and analysed offline. Responders were defined as persons who had 10% or more activated basophils above background, or a T(χ) > 4, for two consecutive dilutions of anti-FcεRI antibody.Results
More basophils (median 1164 vs. median 397) and better discrimination of upregulated CD203c and CD63 amongst responders were obtained after lysis with Saponin than after lysis with formic acid. We suggest that CD203c may be a more sensitive marker for the BAT than CD63, as 6/11 responders were found with CD203c, compared with 3/11 with CD63. Most responders (7/11) were identified with probability binning.Conclusion
A combination of lysis with Saponin and the markers CD203c and CD63 computed by probability binning may be the most sensitive method of detecting activation of basophils after stimulation through FcεRI. 相似文献8.
J. B. Goloran C. R. Chen I. R. Phillips Z. H. Xu L. M. Condron 《Plant and Soil》2014,374(1-2):565-578
Background and aims
Soil phosphorus (P) indices that have been originally developed and applied to agricultural soils for predicting P uptake by plants were examined in a pot experiment to determine the most suitable index for P availability in bauxite-processing residue sand (BRS).Methods
Pot trials with ryegrass were established using BRS that had been amended with various organic (greenwaste compost, biochar and biosolids) and inorganic (zeolite) materials and different levels of di-ammonium phosphate fertiliser. Soil P availability indices tested included anion-exchange membrane (AEM-P), 0.01 M calcium chloride (CaCl2-P), Colwell-P, and Mehlich 3-P.Results
AEM-P was found to most closely reflect the available P status in BRS across all treatments, and had the strongest associations with plant P uptake compared to Colwell-P, Mehlich 3-P and CaCl2-P. AEM-P was more closely correlated with P uptake by ryegrass than other P indices, while Colwell-P was closely related to leaf dry matter. Interestingly, a strong inverse relationship between plant indices and pH in BRS growth media was observed, and an adequate level of plant P uptake was found only in 15 year-old rehabilitated BRS with pH <?8.0.Conclusions
AEM-P was found to be the most suitable index for evaluating P availability in highly alkaline BRS and pH was an important parameter affecting uptake of P by ryegrass. Importantly, time is required (> 5 years) before improved uptake of P by plants can be observed in rehabilitated residue sand embankments. 相似文献9.
Phosphorus availability in chicken manure is lower with increased stockpiling period, despite a larger orthophosphate content 总被引:2,自引:0,他引:2
Background and aims
The relative proportions of phosphorus (P) forms present in manure will determine the overall availability of manure P to plants; however, the link between the forms of P in manures and manure P availability is unclear. This study compares the bioavailability and P speciation of three manures of different stockpiling duration: less than 1 month, 6 months and 12 months; manures were collected concurrently from a single poultry farm.Methods
Bioavailability to wheat in a glasshouse trial was measured using an isotopic dilution method with manure added at an application rate equivalent to 20 kg P ha?1. Phosphorus speciation was measured by 31P nuclear magnetic resonance (NMR) spectroscopic analysis of NaOH-EDTA extracts of the manures.Results
The addition of all manures significantly increased shoot biomass and P concentration, with the fresh manure having the greatest effect. Addition of the fresh manure resulted in the largest labile P pool, highest manure P uptake and manure P recovery, while the manure stockpiled for 12 months resulted in the lowest manure P uptake and manure P recovery. NMR analysis indicated that there was more monoester organic P, especially phytate, in manure stockpiled for shorter periods, while the proportion of manure P that was orthophosphate increased with stockpiling time.Conclusions
Together, these results imply that although the proportion of total P in the manures detected as orthophosphate was higher with longer stockpiling, only a fraction of this orthophosphate was plant-available. This suggests the availability of P from orthophosphate in manures decreases with longer stockpiling time in much the same way that P from orthophosphate in mineral fertilizer becomes less available in soil over time. 相似文献10.
Root-induced processes controlling phosphate availability in soils with contrasted P-fertilized treatments 总被引:1,自引:0,他引:1
Nicolas Devau Philippe Hinsinger Edith Le Cadre Fr��d��ric G��rard 《Plant and Soil》2011,348(1-2):203-218
Aims
In this study we identified the nature of the root-induced chemical processes controlling changes in phosphate (P) availability in a soil with two P loadings resulting from long-term fertilization treatments.Methods
We used a set of mechanistic adsorption models (surface complexation and ion exchange) within the framework of the component additive approach to simulate the effect of durum wheat roots on P availability. We had to consider the influence of adsorption of other ions to ensure the goodness-of-fit of the simulations.Results
We found that Ca2+ uptake, in addition to P uptake and root-induced alkalization, controlled P availability in the rhizosphere regardless of the fertilization level. The relative influence of these three processes depends primarily on the extractant used to estimate P availability. Calcium uptake was the most significant process in water extracts, whereas P uptake was the dominant root-induced chemical process in CaCl2 extracts. Under low Ca concentrations, Ca2+ uptake decreased the promoting influence of Ca2+ adsorption on P adsorption.Conclusions
In addition to confirming the validity of our approach to model P availability, the present investigation indicated that root-induced processes markedly affect P availability irrespective of the fertilization level. 相似文献11.
Background
The production of fuel-grade ethanol from lignocellulosic biomass resources has the potential to increase biofuel production capacity whilst minimising the negative environmental impacts. These benefits will only be realised if lignocellulosic ethanol production can compete on price with conventional fossil fuels and if it can be produced commercially at scale. This paper focuses on lignocellulosic ethanol production in Europe. The hypothesis is that the eventual cost of production will be determined not only by the performance of the conversion process but by the performance of the entire supply-chain from feedstock production to consumption. To test this, a model for supply-chain cost comparison is developed, the components of representative ethanol supply-chains are described, the factors that are most important in determining the cost and profitability of ethanol production are identified, and a detailed sensitivity analysis is conducted.Results
The most important cost determinants are the cost of feedstocks, primarily determined by location and existing markets, and the value obtained for ethanol, primarily determined by the oil price and policy incentives. Both of these factors are highly uncertain. The best performing chains (ethanol produced from softwood and sold as a low percentage blend with gasoline) could ultimately be cost competitive with gasoline without requiring subsidy, but production from straw would generally be less competitive.Conclusion
Supply-chain design will play a critical role in determining commercial viability. The importance of feedstock supply highlights the need for location-specific assessments of feedstock availability and price. Similarly, the role of subsidies and policy incentives in creating and sustaining the ethanol market highlights the importance of political engagement and the need to include political risks in investment appraisal. For the supply-chains described here, and with the cost and market parameters selected, selling ethanol as a low percentage blend with gasoline will maximise ethanol revenues and minimise the need for subsidies. It follows, therefore, that the market for low percentage blends should be saturated before markets for high percentage blends. 相似文献12.
Zhigang Liu Fei Gao Xiaoru Cheng Kai Yang 《Chemical Speciation and Bioavailability》2016,28(1-4):26-32
Biochars converted from agricultural residuals can effectively remove ammonium from water. This work further improved the sorption ability of biochars to aqueous ammonium through alkali modification. Three modified biochars were prepared from agricultural residuals pre-treated with NaOH solution through low-temperature (300 °C) slow pyrolysis. The modified biochars effectively removed ammonium ions from water under various conditions with relatively fast adsorption kinetics (reached equilibrium within 10 h) and extremely high adsorption capacity (>200 mg/g). The Langmuir maximum capacity of the three modified biochars were between 313.9 and 518.9 mg/g, higher than many other ammonium adsorbents. Although the sorption of ammonium onto the modified biochar was affected by pH and temperature, it was high under all of the tested conditions. Findings from this work indicated that alkali-modified biochars can be used as an alternative adsorbent for the removal of ammonium from wastewater. 相似文献
13.
Nanoscale organo-mineral reactions of biochars in ferrosol: an investigation using microscopy 总被引:3,自引:0,他引:3
Yun Lin Paul Munroe Stephen Joseph Stephen Kimber Lukas Van Zwieten 《Plant and Soil》2012,357(1-2):369-380
Aims
In this study, a chicken manure biochar (CM biochar) and a paper sludge biochar (PS biochar), prepared under similar treatment conditions, were amended into ferrosol as part of an agronomic field trial. The aim of this study is to investigate interactions between these biochars and the soil after a 3 month trial.Methods
Soil samples following field trials were taken and biochar was separated from the soil, and studied for both surface oxidation and the degree of interaction with surrounding soil by X-ray photoelectron spectroscopy (XPS), SEM and TEM equipped with EDS for elemental analysis.Results
Following incubation in field soil, both biochars showed that soil mineral incorporation on to their surfaces occurred within the first year, although the attachment was localized at specific sites on the surface. A relatively high concentration of Al was found at the interface between the biochar and mineral phases in both aged biochars, indicating a binding role of Al. For the CM biochar, a soil-iron redox reaction may be associated with the formation of biochar-mineral complexes due to the relatively higher labile carbon content and higher pH value of this biochar.Conclusions
Soil mineral attachment may occur directly on to the biochar surface because of the formation of carboxylic and phenolic functional groups on the aged CM biochar surface by an oxidation reaction. For the PS biochar, adsorption of organic matter from the soil facilitated interactions between the biochar and mineral phases in the soil. Calcium is believed to be important in this process. 相似文献14.
Nutrient availability and pH jointly constrain microbial extracellular enzyme activities in nutrient-poor tundra soils 总被引:1,自引:0,他引:1
Background and aims
Tundra soils, which usually contain low concentrations of soil nutrients and have a low pH, store a large proportion of the global soil carbon (C) pool. The importance of soil nitrogen (N) availability for microbial activity in the tundra has received a great deal of attention; however, although soil pH is known to exert a considerable impact on microbial activities across ecosystems, the importance of soil pH in the tundra has not been experimentally investigated.Methods
We tested a hypothesis that low nutrient availability and pH may limit microbial biomass and microbial capacity for organic matter degradation in acidic tundra heaths by analyzing potential extracellular enzyme activities and microbial biomass after 6 years of factorial treatments of fertilization and liming.Results
Increasing nutrients enhanced the potential activity of β-glucosidase (synthesized for cellulose degradation). Increasing soil pH, in contrast, reduced the potential activity of β-glucosidase. The soil phospholipid fatty acid concentrations (PLFAs; indicative of the amount of microbial biomass) increased in response to fertilization but were not influenced by liming.Conclusions
Our results show that soil nutrient availability and pH together control extracellular enzyme activities but with largely differing or even opposing effects. When nutrient limitation was alleviated by fertilization, microbial biomass and enzymatic capacity for cellulose decomposition increased, which likely facilitates greater decomposition of soil organic matter. Increased soil pH, in contrast, reduced enzymatic capacity for cellulose decomposition, which could be related with the bioavailability of organic substrates. 相似文献15.
Ana Lázaro-Nogal Silvia Matesanz Teresa E. Gimeno Adrián Escudero Fernando Valladares 《Plant and Soil》2012,358(1-2):213-223
Background and aims
Plant-soil interactions are a crucial component of ecosystem functioning. However, most global change studies focus on plant communities, with information on soil properties and performance being scarce. Our goal was to assess the individual and joint effect of habitat heterogeneity and three global change drivers (fragmentation, loss of habitat quality and climate change) on nutrient availability and soil microbial activity in Mediterranean gypsum soils.Methods
We collected soil samples from an experimental field site from large/small fragments, with high/low habitat quality, subjected to two levels of water availability (dry/mesic) and from two microhabitats (under the canopy of shrubs and in the open). We analyzed nutrient concentrations (C, N and P) and enzymatic activities (?-glucosidase, urease and acid phosphatase).Results
C, N, P content, ?-glucosidase, urease and acid phosphatase activities were higher under the canopy than in the open and in high- than in poor- habitat quality sites. These differences were exacerbated in small fragments.Conclusions
The strong interdependence between plant and soil was modulated by fragmentation in the Mediterranean gypsum soils studied. Drought did not exert a direct negative effect on soil properties, although the effect might arise under more intense drought or under drought taking place at times of the year different from those explored here. Results highlight the importance of considering several drivers simultaneously to forecast realistic ecosystem responses to global change. 相似文献16.
Characterization of North American Lignocellulosic Biomass and Biochars in Terms of their Candidacy for Alternate Renewable Fuels 总被引:2,自引:0,他引:2
Sonil Nanda Pravakar Mohanty Kamal K. Pant Satyanarayan Naik Janusz A. Kozinski Ajay K. Dalai 《Bioenergy Research》2013,6(2):663-677
The use of lignocellulosic biomass as a renewable energy source is becoming progressively essential. Much attention is focused on identifying suitable biomass species that can provide high energy outputs to replace conventional fossil fuels. The current study emphasizes on some commonly available biomasses in North America such as pinewood, timothy grass, and wheat straw for their usage towards next generation biofuels. Fast pyrolysis of the feedstocks was performed at 450 °C to generate biochars that were further characterized to advocate their energy and agronomic relevance. The biomasses were examined physiochemically to understand their compositional and structural characteristics through analytical approaches such as CHNS (carbon–hydrogen–nitrogen–sulfur), ICP-MS (inductively coupled plasma-mass spectrometry), particle size, FTIR (Fourier transform infrared) and Raman spectroscopy, thermogravimetric and differential thermogravimetric, XRD (X-ray diffraction), and high-pressure liquid chromatography. The chemical composition of feedstocks significantly differed from that of biochars and the variations among feedstock composition were also found to be greater than for biochars. The presence of cellulose, hemicellulose, and lignin along with other organic components were identified in the spectroscopic and chromatographic analysis. The FTIR spectra of biochars showed removal of oxygen- and hydrogen-containing functionalities from feedstocks due to pyrolysis at higher temperature, although retaining certain significant cellulose-derived functionalities. A number of crystallographic phases in the XRD of biomass, ash, and biochars were due to minerals commonly Na, Mg, Al, Ca, Fe, and Mn. ICP-MS of biochars demonstrated substantial amount of alkali elements indicating their compatibility towards soil amendment for restoring degraded soils. 相似文献
17.
Bioavailability of zinc and phosphorus in calcareous soils as affected by citrate exudation 总被引:2,自引:0,他引:2
Aims
Zinc (Zn) and phosphorus (P) deficiency often occurs at the same time and limits crop production in many soils. It has been suggested that citrate root exudation is a response of plants to both deficiencies. We used white lupin (Lupinus albus L.) as a model plant to clarify if citrate exuded by roots could increase the bioavailability of Zn and P in calcareous soils.Methods
White lupin was grown in nutrient solution and in two calcareous soils in a rhizobox. Rhizosphere soil solution was sampled to determine citrate, metals and P. Based on the measured citrate concentrations, a soil extraction experiment with citrate as extractant was done.Results
Absence of Zn triggered neither cluster root formation nor citrate exudation of white lupin grown in nutrient solution, whereas low P supply did. The maximum citrate concentration (~1.5?mM) found in the cluster rhizosphere soil solution of one soil mobilized P, but not Zn. In the other soil the highest citrate concentration (~0.5?mM) mobilized both elements.Conclusions
White lupin does not respond to low Zn bioavailability by increasing citrate exudation. Such a response was observed at low P supply only. Whether Zn and P can be mobilized by citrate is soil-dependent and the possible controlling mechanisms are discussed. 相似文献18.
Background
Phosphorus (P) deficiency is wide-spread in agricultural soils. In light of increasing P fertilizer costs, it is of interest to assess the capacity of soil microbes to mobilise native soil P and added P. There is currently no method to assess P mobilisation in situ.Methods
The soil P mobilisation potential was assessed by incubating low P soil for up to 30?days with poorly available P sources; C and N were added to increase microbial activity and ensure that only P was limiting microbial growth.Results
The increase in microbial P from day 0 to day 15 showed that microbes were able to mobilise P from FePO4 and phytate. The P mobilisation potential (sum of microbial and resin P) of the rhizosphere soil decreased in the following order: faba bean > chickpea and white lupin > wheat. After 10?days, up to 80% of the mobilised P was microbial P, whereas after 30?days, almost all P mobilised was resin P.Conclusions
The method developed in this study is useful assessing not only potential of a soil to mobilise P but also, by using different poorly available P sources, the mechanisms of P mobilisation. 相似文献19.
Marie J. Zwetsloot Johannes Lehmann Taryn Bauerle Steven Vanek Rachel Hestrin Abebe Nigussie 《Plant and Soil》2016,408(1-2):95-105
Aims
The objectives of this study were to evaluate (1) the fertilizer potential of bone char, (2) the effects of wood biochar on plant-available phosphorus (P), and (3) the role of root-mycorrhizae-biochar interactions in plant P acquisition from a P-fixing soil.Methods
Incubation and pot experiments were conducted with a P-fixing soil and maize with or without root hairs and arbuscular mycorrhizae (AM) inoculation. Olsen-, resin-P and plant P accumulation were used to estimate P availability from bone char, co-pyrolyzed bone char-wood biochar, and separate bone char and wood biochar additions produced at 60, 350 and 750 °C, and Triple Superphosphate (TSP).Results
Maize inoculated with AM showed similar P accumulation when fertilized with either 750 °C bone char or TSP. Pyrolyzing bone did not increase extractable P in soil in comparison to unpyrolyzed bone, apart from a 67 % increase in resin-extractable P after additions of bone char pyrolyzed at 350 °C. Despite greater Olsen-P extractability, co-pyrolysis of bone with wood reduced maize P uptake. Wood biochars reduced resin-P from bone char by 14–26 %, whereas oven-dried wood increased resin-P by 23 %.Conclusions
Bone char is an effective P fertilizer, especially if root-AM interactions are simultaneously considered. Biochar influences plant access to soil P and requires careful management to improve P availability.20.
Yasunori Kikuchi Masahiko Hirao Hirokazu Sugiyama Stavros Papadokonstantakis Konrad Hungerbühler Takashi Ookubo Akinobu Sasaki 《The International Journal of Life Cycle Assessment》2014,19(2):307-319