scholarly journals A novel isotope pool dilution approach to quantify gross rates of key abiotic and biological processes in the soil phosphorus cycle

2019 ◽  
Author(s):  
Wolfgang Wanek ◽  
David Zezula ◽  
Daniel Wasner ◽  
Maria Mooshammer ◽  
Judith Prommer
Keyword(s):  
Soil Phosphorus ◽  
Quality Data ◽  
Organic P ◽  
Phosphorus Cycle ◽  
Soil P ◽  
Environmental Controls ◽  
Abiotic Controls ◽  
Malachite Green Assay ◽  
P Cycle ◽  
Isotope Pool Dilution

Abstract. Efforts to understand and model the current and future behavior of the global phosphorus (P) cycle are limited by the availability of global data on gross rates of soil P processes, as well as its environmental controls. We here present a novel isotope pool dilution approach using 33P labelling of live and sterile soils, which allows to obtain high quality data on gross fluxes of soil inorganic P (Pi) sorption and desorption, as well as of gross fluxes of organic P mineralization and microbial Pi uptake. At the same time, net immobilization of 33Pi by soil microbes and abiotic sorption can be easily derived and partitioned. Compared to other approaches, we used short incubation times (up to 48 h), avoiding tracer re-mineralization, which was confirmed by separation of organic P and Pi using isobutanol fractionation. This approach is also suitable for strongly weathered and P impoverished soils, as sensitivity is increased by extraction of exchangeable bio-available Pi (Olsen Pi; 0.5 M NaHCO3) followed by Pi measurement using the malachite green assay. Biotic processes were corrected for desorption/sorption processes by using adequate sterile abiotic controls that exhibited negligible microbial and extracellular phosphatase activities. Gross rates are calculated using analytical solutions of tracer kinetics, which also allows to study gross soil P dynamics under non-steady-state conditions. Finally, we present major environmental controls of gross and net P cycle processes that were measured for three P-poor tropical forest and three P-rich temperate grassland soils.

scholarly journals A novel isotope pool dilution approach to quantify gross rates of key abiotic and biological processes in the soil phosphorus cycle

2019 ◽  
Vol 16 (15) ◽  
pp. 3047-3068 ◽  
Author(s):  
Wolfgang Wanek ◽  
David Zezula ◽  
Daniel Wasner ◽  
Maria Mooshammer ◽  
Judith Prommer
Keyword(s):  
Soil Phosphorus ◽  
Quality Data ◽  
Organic P ◽  
Phosphorus Cycle ◽  
Soil P ◽  
Environmental Controls ◽  
Abiotic Controls ◽  
Malachite Green Assay ◽  
P Cycle ◽  
Isotope Pool Dilution

Abstract. Efforts to understand and model the current and future behavior of the global phosphorus (P) cycle are limited by the availability of global data on rates of soil P processes, as well as their environmental controls. Here, we present a novel isotope pool dilution approach using 33P labeling of live and sterile soils, which allows for high-quality data on gross fluxes of soil inorganic P (Pi) sorption and desorption, as well as of gross fluxes of organic P mineralization and microbial Pi uptake to be obtained. At the same time, net immobilization of 33Pi by soil microbes and abiotic sorption can be easily derived and partitioned. Compared with other approaches, we used short incubation times (up to 48 h), avoiding tracer remineralization, which was confirmed by the separation of organic P and Pi using isobutanol fractionation. This approach is also suitable for strongly weathered and P-impoverished soils, as the sensitivity is increased by the extraction of exchangeable bioavailable Pi (Olsen Pi; 0.5 M NaHCO3) followed by Pi measurement using the malachite green assay. Biotic processes were corrected for desorption/sorption processes using adequate sterile abiotic controls that exhibited negligible microbial and extracellular phosphatase activities. Gross rates were calculated using analytical solutions of tracer kinetics, which also allowed for the study of gross soil P dynamics under non-steady-state conditions. Finally, we present major environmental controls of gross P-cycle processes that were measured for three P-poor tropical forest and three P-rich temperate grassland soils.

scholarly journals Litter inputs and phosphatase activity affect the temporal variability of organic phosphorus in a tropical forest soil in the Central Amazon

2021 ◽  
Author(s):  
Karst J. Schaap ◽  
Lucia Fuchslueger ◽  
Marcel R. Hoosbeek ◽  
Florian Hofhansl ◽  
Nathielly Pires Martins ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Phosphatase Activity ◽  
Litter Decomposition ◽  
Soil Phosphorus ◽  
Litter Production ◽  
P Availability ◽  
Organic P ◽  
Phosphorus Cycle ◽  
P Fractions ◽  
Soil P

Abstract Purpose The tropical phosphorus cycle and its relation to soil phosphorus (P) availability are a major uncertainty in projections of forest productivity. In highly weathered soils with low P concentrations, plant and microbial communities depend on abiotic and biotic processes to acquire P. We explored the seasonality and relative importance of drivers controlling the fluctuation of common P pools via processes such as litter production and decomposition, and soil phosphatase activity. Methods We analyzed intra-annual variation of tropical soil phosphorus pools using a modified Hedley sequential fractionation scheme. In addition, we measured litterfall, the mobilization of P from litter and soil extracellular phosphatase enzyme activity and tested their relation to fluctuations in P- fractions. Results Our results showed clear patterns of seasonal variability of soil P fractions during the year. We found that modeled P released during litter decomposition was positively related to change in organic P fractions, while net change in organic P fractions was negatively related to phosphatase activities in the top 5 cm. Conclusion We conclude that input of P by litter decomposition and potential soil extracellular phosphatase activity are the two main factors related to seasonal soil P fluctuations, and therefore the P economy in P impoverished soils. Organic soil P followed a clear seasonal pattern, indicating tight cycling of the nutrient, while reinforcing the importance of studying soil P as an integrated dynamic system in a tropical forest context.

scholarly journals Roles of Phosphate Solubilizing Microorganisms from Managing Soil Phosphorus Deficiency to Mediating Biogeochemical P Cycle

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 158
Author(s):  
Jiang Tian ◽  
Fei Ge ◽  
Dayi Zhang ◽  
Songqiang Deng ◽  
Xingwang Liu
Keyword(s):  
Phosphorus Deficiency ◽  
Soil Phosphorus ◽  
Biological Molecules ◽  
P Deficiency ◽  
Soil P ◽  
Soil Systems ◽  
Intensively Managed ◽  
Phosphate Solubilizing ◽  
P Fertilizers ◽  
P Cycle

Phosphorus (P) is a vital element in biological molecules, and one of the main limiting elements for biomass production as plant-available P represents only a small fraction of total soil P. Increasing global food demand and modern agricultural consumption of P fertilizers could lead to excessive inputs of inorganic P in intensively managed croplands, consequently rising P losses and ongoing eutrophication of surface waters. Despite phosphate solubilizing microorganisms (PSMs) are widely accepted as eco-friendly P fertilizers for increasing agricultural productivity, a comprehensive and deeper understanding of the role of PSMs in P geochemical processes for managing P deficiency has received inadequate attention. In this review, we summarize the basic P forms and their geochemical and biological cycles in soil systems, how PSMs mediate soil P biogeochemical cycles, and the metabolic and enzymatic mechanisms behind these processes. We also highlight the important roles of PSMs in the biogeochemical P cycle and provide perspectives on several environmental issues to prioritize in future PSM applications.

Phosphorus cycling in wheat-pasture rotations. III. Organic phosphorus turnover and phosphorus cycling

Soil Research ◽  
1988 ◽  
Vol 26 (2) ◽  
pp. 343 ◽  
Author(s):  
MJ Mclaughlin ◽  
AM Alston ◽  
JK Martin
Keyword(s):  
Organic Phosphorus ◽  
Soil Surface ◽  
P Uptake ◽  
Phosphorus Cycling ◽  
Plant Residue ◽  
Organic P ◽  
Inorganic P ◽  
Soil P ◽  
Wheat Pasture ◽  
P Cycle

The incorporation of 32P and 33P from 33P-labelled fertilizer and 33P-labelled pasture residues into organic and inorganic fractions of soil P was studied in a solonized brown soil (Calcixerollic xerochrept) cropped to wheat (Triticum aestivum). Most of the plant residue 33P was present as inorganic P at the time it was added to the soil, but only 7 days later almost 40% had been incorporated into organic P fractions of the soil. As the fertilizer was banded near the soil surface at sowing, little of the 32P from the 32P-labelled fertilizer was incorporated into organic forms, even after 95 days. From a knowledge of the P uptake by the plants and microorganisms, an integrated P cycle for this soil under wheat-pasture rotations was developed. We propose that fertilization of the pasture phase of the rotation stimulates the build-up of residual inorganic and organic P, while fertilization of the wheat phase predominantly stimulates the accumulation of inorganic forms of P in the soil.

Responses of herbage yield and soil phosphorus fractions to phosphorus fertilisation on a degraded arid steppe

2018 ◽  
Vol 69 (8) ◽  
pp. 846 ◽  
Author(s):  
Dangjun Wang ◽  
Zhibin He ◽  
Zhen Zhang ◽  
Qingfeng Du ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Soil Phosphorus ◽  
Pot Experiment ◽  
Available Phosphorus ◽  
P Availability ◽  
Organic P ◽  
Soil P ◽  
Sheep Manure ◽  
Arid Steppe ◽  
Plant Yields ◽  
Phosphorus Fertilisation

Low plant-available phosphorus (P) in degraded arid steppes greatly limits plant yields. However, whether exterior P addition will improve the soil P availability and thus increase plant yield in these degraded arid steppes is still not certain. In the current study, a severely degraded arid steppe in Inner Mongolia, China, with soil-available P <5 mg/kg, was fertilised annually with chemical or manure P for two years (2014, dry year; 2015, wet year). There were six fertilisation treatments: 0, 30 kg P/ha, 60 kg P/ha, 90 kg P/ha, 4000 kg sheep manure/ha (equalling 16.4 kg P/ha) and 8000 kg sheep manure/ha (32.8 kg P/ha). A pot experiment with Stipa krylovii (the dominant plant species in the tested steppe) and five P application rates (0, 30, 60, 90 and 120 kg P/ha) was also conducted, under well-watered and nitrogen-fertilised conditions, using surface soils from unfertilised plots in the field. Results indicated that the tested soils had strong P adsorption capacity and weaker desorption capacity, and that the labile P fractions were quickly transformed into less labile fractions, reducing P availabilities. Overall, chemical P fertiliser resulted in the accumulation of Ca10-P and occluded P, whereas sheep manure resulted in the accumulation of moderately resistant organic P and highly resistant organic P. Phosphorus fertilisation was associated with an increase in plant P concentrations in both 2014 and 2015, and a low P rate (30 kg P/ha in the current study) was able to improve the aboveground biomass in both the field experiment in the wet year and the pot experiment under well-watered conditions. Thus, in degraded arid steppes, P fertilisation may be unnecessary in dry years. A low rate of P fertilisation is recommended in wet years to improve soil P status and steppe plant productivity.

scholarly journals Implications of long-term superphosphate applications on the accumulation and plant availability of soil phosphorus under irrigated pastures

1990 ◽  
pp. 191-193
Author(s):  
L.M. Condron ◽  
K.M. Goh
Keyword(s):  
Dynamic Balance ◽  
Soil Phosphorus ◽  
Organic P ◽  
P Fractionation ◽  
Inorganic P ◽  
Soil P ◽  
Grazed Pasture ◽  
P Addition ◽  
Apparent Stability

Changes in soil phosphorus (P) associated with the establishment and maintenance of improved ryegrass-clover pasture under different superphosphate fertiliser treatments were examined over a 20-year period (1957-77). Results showed that soil organic P increased with increasing applications of P fertiliser. This represents a dynamic balance between rates of organic P addition and breakdown in the soil. This balance is reached slowly and may be significantly altered only by drastic changes in land use. In annually fertilised soils, amounts of inorganic P increased with time. However, the potential utilisation of this residual inorganic P is limited by its apparent stability in the soil. Keywords grazed pasture, irrigation, fertiliser P, soil inorganic P, soil organic P, soil P fractionation

scholarly journals Reviews and Syntheses: Ironing Out Wrinkles in the Soil Phosphorus Cycling Paradigm

2020 ◽  
Author(s):  
Curt A. McConnell ◽  
Jason P. Kaye ◽  
Armen R. Kemanian
Keyword(s):  
Soil Phosphorus ◽  
Phosphorus Cycling ◽  
Organic P ◽  
New Techniques ◽  
Inorganic P ◽  
Soil P ◽  
Plant System ◽  
P Sorption ◽  
P Cycling ◽  
Critical Challenge

Abstract. Soil phosphorus (P) management remains a critical challenge for agriculture worldwide, and yet we are still unable to predict soil P dynamics as confidently as that of carbon (C) or nitrogen (N). This is due to both the complexity of inorganic P (Pi) and organic P (Po) cycling and the methodological constraints that have limited our ability to trace P dynamics in the soil-plant system. In this review we describe the challenges to building parsimonious, accurate, and useful P models and to explore the potential of some new techniques to advance modeling efforts. To advance our understanding and modeling of P biogeochemistry, research efforts should focus on the following: 1) update the McGill and Cole (1981) model of Po mineralization by clarifying the role and prevalence of “biochemical” and “biological” Po mineralization which we hypothesize are not mutually exclusive and may co-occur along a continuum of Po substrate stoichiometry; 2) further understand the dynamics of phytate, a 6-C compound that can regulate the poorly understood stoichiometry of soil P; 3) explore the effects of C and Po saturation on P sorption and Po mineralization; and 4) resolve discrepancies between hypotheses about P cycling and the methods used to test these hypotheses.

THE INFLUENCE OF TOPOGRAPHY ON THE DISTRIBUTION OF ORGANIC AND INORGANIC SOIL PHOSPHORUS ACROSS A NARROW ENVIRONMENTAL GRADIENT

1985 ◽  
Vol 65 (4) ◽  
pp. 651-665 ◽  
Author(s):  
T. L. ROBERTS ◽  
J. W. B. STEWART ◽  
J. R. BETTANY
Keyword(s):  
Environmental Gradient ◽  
Soil Phosphorus ◽  
Regional Distribution ◽  
Extraction Procedure ◽  
Distribution Patterns ◽  
Organic P ◽  
Inorganic P ◽  
Soil P ◽  
Lower Slope ◽  
Total P

A sequential extraction procedure was used to determine phosphorus fractions (resin, bicarbonate, hydroxide, sonicated hydroxide, acid and acid-peroxide digest with separate organic and inorganic P determinations) in surface and subsurface horizons taken from the upper, mid- and lower slope positions of four catenas (representing Brown, Dark Brown and Black Chernozemic soils, and a Luvisolic soil) which encompass a narrow environmental gradient of climate (annual precipitation: 300–475 mm) and vegetation. Trends in the local distribution of organic and inorganic soil P between upper and lower slope positions in any one catena were similar to the regional distribution patterns across all soil zones. Concentration of organic P, in both the surface and subsurface horizons, increased from the upper to the lower slope positions and from the Brown to the Black soils, while inorganic P decreased. The largest single organic fraction (hydroxide extractable) accounted for up to 22 and 17% of the total P (surface and subsurface horizons, respectively). Acid extractable P dominated the inorganic fractions, accounting for 40–63% of the total P (surface and subsurface horizons, respectively). The distribution of organic P along the catenas and among the soil zones was related to the transformations of inorganic P caused by differences in weathering intensity between slope positions and across the Province. Key words: Catena, climo-toposequence, sequential P extraction

scholarly journals Reviews and syntheses: Ironing out wrinkles in the soil phosphorus cycling paradigm

2020 ◽  
Vol 17 (21) ◽  
pp. 5309-5333
Author(s):  
Curt A. McConnell ◽  
Jason P. Kaye ◽  
Armen R. Kemanian
Keyword(s):  
Soil Phosphorus ◽  
Phosphorus Cycling ◽  
Organic P ◽  
New Techniques ◽  
Inorganic P ◽  
Soil P ◽  
Plant System ◽  
P Sorption ◽  
Biogeochemical Models ◽  
Critical Challenge

Abstract. Soil phosphorus (P) management remains a critical challenge for agriculture worldwide, and yet we are still unable to predict soil P dynamics as confidently as that of carbon (C) or nitrogen (N). This is due to both the complexity of inorganic P (Pi) and organic P (Po) cycling and the methodological constraints that have limited our ability to trace P dynamics in the soil–plant system. In this review, we describe the challenges for building parsimonious, accurate, and useful biogeochemical models that represent P dynamics and explore the potential of new techniques to usher P biogeochemistry research and modeling forward. We conclude that research efforts should focus on the following: (1) updating the McGill and Cole (1981) model of Po mineralization by clarifying the role and prevalence of biochemical and biological Po mineralization, which we suggest are not mutually exclusive and may co-occur along a continuum of Po substrate stoichiometry; (2) further understanding the dynamics of phytate, a six C compound that can regulate the poorly understood stoichiometry of soil P; (3) exploring the effects of C and Po saturation on P sorption and Po mineralization; and (4) resolving discrepancies between hypotheses about P cycling and the methods used to test these hypotheses.

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