https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_5/b_fdi_18-19/25866.pdf

Some podzols on Bateke sands and their origins, People's Republic of Congo

Zinc adsorption-desorption on short-range ordered iron oxide as influenced by citric acid during its formation

Silcreteexposed at Landslip Hill forms part of the Early Miocene Gore Lignite Measures. The silcrete, well known for its diverse fossil megaflora of leaves and cones, is up to 8 m thick and consists of silica-cemented alluvial channel and channel-margin deposits. Five sedimentary facies are differentiated: quartz pebble conglomerate; trough cross-stratified coarse grained sandstone; planar laminated fine and medium grained sandstone; mottled sandstone pervaded by root structures; and mud-clast conglomerate. Measurements of 113 horizontal log moulds show a preferred north-south alignment, parallel with the north-southpaleocurrent direction indicated by three trough cross-stratification axes. Field and petrological observations indicate cementation started soon after deposition. Secondary silica consists of spherulitic and granular chalcedony, microcrystalline quartz, and syntaxial quartz overgrowths. Although sandstone in places shows intergranular “pressure solution” textures, the plant fossils a...

https://www.tandfonline.com/doi/pdf/10.1080/00288306.1990.10427579

Deposition and diagenesis of Landslip Hill silcrete, Gore Lignite Measures (Miocene), New Zealand

Plants can change the soil that they grow on, for example by producing litter. If litter characteristics are such that their effect on the soil increases a plant's fitness, a positive feedback can develop between the plant and the soil. Several studies indicate that New Zealand kauri trees (Agathis australis) lower the availability of nutrients in the soil beneath their crown. Low nutrient availability would be positive for the survival of kauri seedlings as they are known to use nutrients more efficiently than angiosperm species. We tested the hypotheses that nutrient availability is lower and light availability is higher beneath kauri trees than beneath the surrounding angiosperm vegetation. We determined the availability of nutrients (using leaf nutrient concentrations as a proxy), soil moisture, and light in both situations. As a reference we did the same measurements in tea tree vegetation (Leptospermum scoparium and Kunzea ericoides) where kauri seedlings were abundant. The availability of nitrogen, phosphorus and calcium was lower under kauri than in the surrounding vegetation. Further, in a dry period the availability of water in the organic layer surrounding the kauri trunk was lower than in the mineral soil further away from the kauri trunk. We suggest that periodic drought explains why the density of kauri seedlings under mature kauri trees is less than in tea tree vegetation. Kauri seedlings are more tolerant of drought and low nutrient availability than other tree seedlings and we conclude that the conditions under mature kauri give kauri seedlings an advantage over seedlings of other tree species. The low nutrient availability under mature kauri trees supports the idea of a positive soil?plant feedback driven by poor decomposability of kauri litter.

/pdf/kauri-trees-agathis-australis-affect-nutrient-water-and-4je90zq7lg.pdf

Kauri trees (Agathis australis) affect nutrient, water and light availability for their seedlings

Les podzols sont des sols acides de milieux forestiers caracterises par l'accumulation de fer (Fe) et d'aluminium (Al) dans l'horizon B (horizon B podzolique). Ils couvrent de vastes etendues des zones boreales et temperees humides et sont associes a des substrats a texture grossiere. La connaissance des mecanismes responsables de la formation des podzols est essentielle a la comprehension, la modelisation et la gestion des ecosystemes forestiers, agricoles et aquatiques et a la prevision de leurs reactions face a des changements des conditions environnementales. Quatre theories majeures, ou modeles conceptuels, ont ete proposees afin de representer la genese des podzols : la theorie des fulvates (Stobbe et Wright, 1959; McKeague et al., 1978), la theorie de la proto-imogolite (Farmer et al., 1980; Anderson et al., 1982), la theorie des compartiments chimiques (Ugolini et Dahlgren, 1987) et la theorie des polymeres d'AI (Browne, 1995). Celles-ci ont mis en relief le role de certains processus tels que la creation et le transport de complexes organo-metalliques, la synthese de la proto-imogolite et la neoformation d'imogolite, l'alteration des mineraux par l'acide carbonique (H2CO3) ainsi que la formation de complexes polymeriques dissouts de type Al-silice (Si). L'importance accordee a chacun de ces processus varie toutefois en fonction de la nature des milieux prospectes lors de la definition d'une theorie particuliere. L'absence d'une theorie globale et integree de la genese des podzols est aussi liee a la comprehension incomplete de la dynamique des podzols, a l'omission de certains processus importants et a l'apparente opposition entre les theories.

/pdf/la-genese-des-podzols-2mnkdjsd8c.pdf

La genèse des podzols

Strengths of a densipan, humus-pan and clay-pan in a Spodosol developed under kauri (Agathis australis) and the implications for soil classification

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

N. Wells

Author Tools

Chat about Author

Papers

Strengths of a densipan, humus-pan and clay-pan in a Spodosol developed under kauri (Agathis australis) and the implications for soil classification