scholarly journals Soil Phosphorus Exchange as Affected by Drying-Rewetting of Three Soils From a Hawaiian Climatic Gradient

2021 ◽  
Vol 1 ◽  
Author(s):  
Julian Helfenstein ◽  
Emmanuel Frossard ◽  
Chiara Pistocchi ◽  
Oliver Chadwick ◽  
Peter Vitousek ◽  
...  
Keyword(s):  
Soil Phosphorus ◽  
P Availability ◽  
Climatic Gradient ◽  
Soil Behavior ◽  
P Concentration ◽  
P Cycling ◽  
Inherent Feature ◽  
History Of ◽  
Climatic History ◽  
P Recovery

Current understanding of phosphorus (P) dynamics is mostly based on experiments carried out under steady-state conditions. However, drying-rewetting is an inherent feature of soil behavior, and as such also impacts P cycling. While several studies have looked at net changes in P pool sizes with drying-rewetting, few studies have dynamically tracked P exchange using isotopes, which would give insights on P mean residence times in a given pool, and thus P availability. Here, we subjected three soils from a climatic gradient on the Kohala peninsula from Hawaii to 5-month drying-rewetting treatments. The hypotheses were that physico-chemical and biotic processes would be differently affected by repeated drying-rewetting cycles, and that response would depend on climatic history of the soils. Soils were labeled with 33P and 18O enriched water. At select time intervals, we carried out a sequential extraction and measured P concentration, 33P recovery (only first 3 months), and incorporation of 18O from water into phosphate. This allowed tracing P dynamics in sequentially extracted pools as well as O dynamics in phosphate, which are driven by biological processes. Results showed that P concentration and 33P recovery were predominantly driven by soil type. However, across all soils we observed faster dilution of 33P from resin-P into less mobile inorganic pools under drying-rewetting. On the other hand, O dynamics in phosphate were mostly governed by drying-rewetting treatment. Under drying-rewetting, considerably less O was incorporated from water into phosphate of resin-P, microbial-P and HCl-P, suggesting that drying-rewetting reduced biological P cycling. Hence, our results suggest that repeated drying-rewetting increases inorganic P exchange while reducing biological P cycling due to reduced microbial activity, independent of climatic history of the soils. This needs to be considered in P management in ecosystems as well as model representations of the terrestrial P cycle.

Interpretation of a single-point P buffering index for adjusting critical levels of the Colwell soil P test

Soil Research ◽  
2007 ◽  
Vol 45 (1) ◽  
pp. 55 ◽  
Author(s):  
P. W. Moody
Keyword(s):  
Buffer Capacity ◽  
Soil Phosphorus ◽  
Single Point ◽  
Maximum Yield ◽  
P Value ◽  
P Availability ◽  
Soil P ◽  
P Concentration ◽  
Soil P Test ◽  
Rate Of Increase

Soil phosphorus (P) buffer capacity is the change in the quantity of sorbed P required per unit change in solution P concentration. Because P availability to crops is mainly determined by solution P concentration, as P buffer capacity increases, so does the quantity of P required to maintain a solution P concentration that is adequate for crop demand. Bicarbonate-extractable P using the Colwell method is the most common soil P test used in Australia, and Colwell-P can be considered to estimate P quantity. Therefore, as P buffer capacity increases, the Colwell-P concentration required for maximum yield also increases. Data from several published and unpublished studies are used to derive relationships between the ‘critical’ Colwell-P value (Colwell-P at 90% maximum yield) and the single-point P buffer index (PBI) for annual medics, soybean, potato, wheat, and temperate pasture. The rate of increase in critical Colwell-P with increasing PBI increases in the order: temperate pasture < medics < wheat < potato. Indicative critical Colwell-P values are given for the 5 crops at each of the PBI categories used to describe soil P buffer capacity as it increases from extremely low to very high.

scholarly journals Long-term nutrient inputs shift soil microbial functional profiles of phosphorus cycling in diverse agroecosystems

2019 ◽  
Vol 14 (3) ◽  
pp. 757-770 ◽  
Author(s):  
Zhongmin Dai ◽  
Guofei Liu ◽  
Huaihai Chen ◽  
Chengrong Chen ◽  
Jingkuan Wang ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Soil Phosphorus ◽  
P Availability ◽  
Nutrient Inputs ◽  
P Cycling ◽  
P Transformation ◽  
Microbial P ◽  
P Immobilization ◽  
Functional Profiles

AbstractMicroorganisms play an important role in soil phosphorus (P) cycling and regulation of P availability in agroecosystems. However, the responses of the functional and ecological traits of P-transformation microorganisms to long-term nutrient inputs are largely unknown. This study used metagenomics to investigate changes in the relative abundance of microbial P-transformation genes at four long-term experimental sites that received various inputs of N and P nutrients (up to 39 years). Long-term P input increased microbial P immobilization by decreasing the relative abundance of the P-starvation response gene (phoR) and increasing that of the low-affinity inorganic phosphate transporter gene (pit). This contrasts with previous findings that low-P conditions facilitate P immobilization in culturable microorganisms in short-term studies. In comparison, long-term nitrogen (N) input significantly decreased soil pH, and consequently decreased the relative abundances of total microbial P-solubilizing genes and the abundances of Actinobacteria, Gammaproteobacteria, and Alphaproteobacteria containing genes coding for alkaline phosphatase, and weakened the connection of relevant key genes. This challenges the concept that microbial P-solubilization capacity is mainly regulated by N:P stoichiometry. It is concluded that long-term N inputs decreased microbial P-solubilizing and mineralizing capacity while P inputs favored microbial immobilization via altering the microbial functional profiles, providing a novel insight into the regulation of P cycling in sustainable agroecosystems from a microbial perspective.

Improved Plant Diversity as a Strategy to Increase Available Soil Phosphorus

2019 ◽  
Vol 103 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Carlos Crusciol ◽  
João Rigon ◽  
Juliano Calonego ◽  
Rogério Soratto
Keyword(s):  
Crop Yields ◽  
Soil Phosphorus ◽  
Cropping System ◽  
P Availability ◽  
P Fractions ◽  
Crop Species ◽  
Soil P ◽  
Residue Decomposition ◽  
Available Soil Phosphorus ◽  
Crop Residue Decomposition

Some crop species could be used inside a cropping system as part of a strategy to increase soil P availability due to their capacity to recycle P and shift the equilibrium between soil P fractions to benefit the main crop. The release of P by crop residue decomposition, and mobilization and uptake of otherwise recalcitrant P are important mechanisms capable of increasing P availability and crop yields.

Paleontology and stratigraphy of Middle Eocene rock units in the southern Green River and Uinta Basins, Wyoming and Utah

2017 ◽  
Vol 4 ◽  
pp. 1-53 ◽  
Author(s):  
Paul Murphey ◽  
K.E. Townsend ◽  
Anthony Friscia ◽  
James Westgate ◽  
Emmett Evanoff ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Middle Eocene ◽  
Green River Basin ◽  
Green River ◽  
Scientific Exploration ◽  
History Of ◽  
Climatic History ◽  
Field Excursion ◽  
Land Mammal ◽  
Bridger Formation

The Bridger Formation is restricted to the Green River Basin in southwest Wyoming, and the Uinta and Duchesne River Formations are located in the Uinta Basin in Utah. These three rock units and their diverse fossil assemblages are of great scientific importance and historic interest to vertebrate paleontologists. Notably, they are also the stratotypes from oldest to youngest for the three middle Eocene North American Land Mammal Ages—the Bridgerian, Uintan, and Duchesnean. The fossils and sediments of these formations provide a critically important record of biotic, environmental, and climatic history spanning approximately 10 million years (49 to 39 Ma). This article provides a detailed field excursion through portions of the Green River and Uinta Basins that focuses on locations of geologic, paleontologic, and historical interest. In support of the field excursion, we also provide a review of current knowledge of these formations with emphasis on lithostratigraphy, biochronology, depositional, and paleoenvironmental history, and the history of scientific exploration.

Late Pleistocene–Holocene environmental and climatic history of a freshwater paramo ecosystem in the northern Andes

2020 ◽  
Vol 35 (8) ◽  
pp. 1046-1056
Author(s):  
Luisa Patiño ◽  
Maria Isabel Velez ◽  
Marion Weber ◽  
César A. Velásquez‐r ◽  
Santiago David ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Northern Andes ◽  
History Of ◽  
Climatic History

Soil phosphorus (P) mining in agriculture – Impacts on P availability, crop yields and soil organic carbon stocks

2021 ◽  
Vol 322 ◽  
pp. 107660
Author(s):  
Stany Vandermoere ◽  
Tomas Van De Sande ◽  
Greet Tavernier ◽  
Lore Lauwers ◽  
Ellen Goovaerts ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Crop Yields ◽  
Soil Phosphorus ◽  
Carbon Stocks ◽  
P Availability ◽  
Soil Organic Carbon Stocks ◽  
P Mining

scholarly journals Atmospheric speciation of rocky planets from magma ocean outgassing

2020 ◽  
Author(s):  
Tim Lichtenberg ◽  
Dan J. Bower ◽  
Mark Hammond ◽  
Ryan Boukrouche ◽  
Shang-Min Tsai ◽  
...  
Keyword(s):  
Coupled Model ◽  
Initial Distribution ◽  
Occurrence Rate ◽  
Magma Ocean ◽  
Mantle Dynamics ◽  
Mantle Geochemistry ◽  
Prebiotic Chemical ◽  
History Of ◽  
Climatic History ◽  
Rocky Planets

&lt;p&gt;The earliest atmospheres of rocky planets originate from extensive volatile release during one or more magma ocean epochs that occur during primary and late-stage assembly of the planet (1). These epochs represent the most extreme cycling of volatiles between the interior and atmosphere in the history of a planet, and establish the initial distribution of the major volatile elements (C, H, N, O, S) between different chemical reservoirs that subsequently evolve via geological cycles. Crucially, the erosion or recycling of primary atmospheres bear upon the nature of the long-lived secondary atmospheres that will be probed with current and future observing facilities (2). Furthermore, the chemical speciation of the atmosphere arising from magma ocean processes can potentially be probed with present-day observations of tidally-locked rocky super-Earths (3). The speciation in turn strongly influences the climatic history of rocky planets, for instance the occurrence rate of planets that are locked in long-term runaway greenhouse states (4). We will present an integrated framework to model the build-up of the earliest atmospheres from magma ocean outgassing using a coupled model of mantle dynamics and atmospheric evolution. We consider the diversity of atmospheres that can arise for a range of initial planetary bulk compositions, and show how even small variations in volatile abundances can result in dramatically different atmospheric compositions and affect earliest mantle geochemistry and atmospheric speciation relevant for surficial prebiotic chemical environments (5). Only through the lense of coupled evolutionary models of terrestrial interiors and atmospheres can we begin to deconvolve the imprint of formation from that of evolution, with consequences for how we interpret the diversity revealed by astrophysical observables, and their relation to the earliest planetary conditions of our home world.&lt;/p&gt; &lt;div class=&quot;&quot;&gt;&lt;em&gt;References&lt;/em&gt;&lt;/div&gt; &lt;ol&gt; &lt;li&gt;Bower, D. J., Kitzmann, D., Wolf, A. S., et al. (2019). Astron. Astrophys. 631, A103.&lt;/li&gt; &lt;li&gt;Bonati, I., Lichtenberg, T., Bower, D. J., et al. (2019). Astron. Astrophys. 621, A125.&lt;/li&gt; &lt;li&gt;Kreidberg, L., Koll, D. D., Morley, C., et al. (2019). Nature 573, 87-90.&lt;/li&gt; &lt;li&gt;Hamano, K., Abe, Y., Genda, H. (2013). Nature 497, 607-610.&lt;/li&gt; &lt;li&gt;Sasselov, D. D., Grotzinger, J. P., Sutherland, J. D. (2020). Sci. Adv. 6, eaax3419.&lt;/li&gt; &lt;/ol&gt;

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