Phosphorus sorption and desorption in oxide-rich Ferralsols of New Caledonia

Soil Research ◽  
2001 ◽  
Vol 39 (2) ◽  
pp. 403 ◽  
Author(s):  
I. G. Dubus ◽  
T. Becquer
Keyword(s):  
Organic Matter ◽  
Crop Production ◽  
Pacific Islands ◽  
New Caledonia ◽  
Clay Fraction ◽  
South Pacific ◽  
Limiting Factors ◽  
P Availability ◽  
P Sorption ◽  
South Pacific Islands

Phosphorus (P) availability in soils is one of the main limiting factors for crop production in Ferralsols that contain high amounts of aluminium and iron oxides. Highly weathered Geric Ferralsols cover large surface areas of south Pacific islands, some of which are required for agricultural development. Sorption and desorption of P in Geric Ferralsols of the island of Maré (New Caledonia) were investigated. The soils contain large quantities of oxides, especially of aluminium. The clay fraction consisted exclusively of fine, discrete oxide particles. Both Freundlich and Langmuir equations provided a good fit to the data for equilibrium P concentrations ranging from 0.05 to 850 mg P/L. The extremely high P sorption capacities of New Caledonian Geric Ferralsols were exemplified by the large Langmuir sorption maxima which ranged from 6400 to 9250 mg P/kg. A strong negative correlation between P sorption and organic matter was noted, resulting in a larger P availability in topsoils. This relationship can be used to provide a first assessment of P sorption capacities of Geric Ferralsols across the island. Management of organic matter is likely to be of major importance in the control of P availability in Geric Ferralsols of south Pacific islands.

A monograph of Entodon (Entodontaceae) in Australia, eastern Melanesia and southern Oceania

1990 ◽  
Vol 3 (4) ◽  
pp. 701 ◽  
Author(s):  
WR Buck
Keyword(s):  
Pacific Islands ◽  
New Caledonia ◽  
South Pacific ◽  
The Philippines ◽  
Pacific Basin ◽  
The South ◽  
South Pacific Islands

The moss genus Entodon C. Müll. (Entodontaceae) is revised for Australia, eastern Melanesia (New Caledonia and Fiji) and the South Pacific islands. The nine validly described species and 10 nomina nuda are reduced to two species, E. mackaviensis C. Müll. and E. plicatus C. Müll. Entodon mackaviensis, with terete branches and extensive alar development is confined to the region treated. Entodon plicatus, with complanate branches and significantly fewer alar cells, ranges from India to the far reaches of the South Pacific basin, and from Tasmania to the Philippines. Both species are described and illustrated. Some extra-limital synonymy is provided.

scholarly journals Decolonisation Processes in the South Pacific Islands: A Comparative Analysis between Metropolitan Powers

1996 ◽  
Vol 26 (2) ◽  
pp. 355
Author(s):  
Paul De Deckker
Keyword(s):  
New Zealand ◽  
Great Britain ◽  
Pacific Islands ◽  
New Caledonia ◽  
Free Association ◽  
South Pacific ◽  
French Polynesia ◽  
The South ◽  
The Pacific ◽  
South Pacific Islands

The South Pacific islands came late, by comparison with Asia and Africa, to undertake the decolonising process. France was the first colonial power in the region to start off this process in accordance with the decision taken in Paris to pave the way to independence for African colonies. The Loi-cadre Defferre in 1957, voted in Parliament, was applied to French Polynesia and New Caledonia as it was to French Africa. Territorial governments were elected in both these Pacific colonies in 1957. They were abolished in 1963 after the return to power of General de Gaulle who decided to use Moruroa for French atomic testing. The status quo ante was then to prevail in New Caledonia and French Polynesia up to today amidst statutory crises. The political evolution of the French Pacific, including Wallis and Futuna, is analysed in this article. Great Britain, New Zealand and Australia were to conform to the 1960 United Nations' recommendations to either decolonise, integrate or provide to Pacific colonies self-government in free association with the metropolitan power. Great Britain granted constitutional independence to all of its colonies in the Pacific except Pitcairn. The facts underlying this drastic move are analysed in the British context of the 1970's, culminating in the difficult independence of Vanuatu in July 1980. New Zealand and Australia followed the UN recommendations and granted independence or self-government to their colonial territories. In the meantime, they reinforced their potential to dominate the South Pacific in the difficult geopolitical context of the 1980s. American Micronesia undertook statutory evolution within a strategic framework. What is at stake today within the Pacific Islands is no longer of a political nature; it is financial.

scholarly journals Describing Phosphorus Sorption Processes on Volcanic Soil in the Presence of Copper or Silver Engineered Nanoparticles

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 373
Author(s):  
Jonathan Suazo-Hernández ◽  
Erwin Klumpp ◽  
Nicolás Arancibia-Miranda ◽  
Patricia Poblete-Grant ◽  
Alejandra Jara ◽  
...  
Keyword(s):  
Organic Matter ◽  
Crop Production ◽  
Agricultural Soils ◽  
Ph Value ◽  
Consumer Products ◽  
Soil Samples ◽  
Engineered Nanoparticles ◽  
P Availability ◽  
Agricultural Crop ◽  
Phosphorus Sorption

Engineered nanoparticles (ENPs) present in consumer products are being released into the agricultural systems. There is little information about the direct effect of ENPs on phosphorus (P) availability, which is an essential nutrient for crop growthnaturally occurring in agricultural soils. The present study examined the effect of 1, 3, and 5% doses of Cu0 or Ag0 ENPs stabilized with L-ascorbic acid (suspension pH 2–3) on P ad- and desorption in an agricultural Andisol with total organic matter (T-OM) and with partial removal of organic matter (R-OM) by performing batch experiments. Our results showed that the adsorption kinetics data of H2PO4− on T-OM and R-OM soil samples with and without ENPs were adequately described by the pseudo-second-order (PSO) and Elovich models. The adsorption isotherm data of H2PO4− from T-OM and R-OM soil samples following ENPs addition were better fitted by the Langmuir model than the Freundlich model. When the Cu0 or Ag0 ENPs doses were increased, the pH value decreased and H2PO4− adsorption increased on T-OM and R-OM. The H2PO4− desorption (%) was lower with Cu0 ENPs than Ag0 ENPs. Overall, the incorporation of ENPs into Andisols generated an increase in P retention, which may affect agricultural crop production.

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