Activité phosphatasique de quelques sols tropicaux à argile 1: 1. Répartition dans les fractions granulométriques

1994 ◽  
Vol 74 (2) ◽  
pp. 121-129 ◽  
Author(s):  
C. Feller ◽  
E. Frossard ◽  
M. Brassard
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Phosphatase Activity ◽  
Mineral Soil ◽  
Clay Fraction ◽  
Continuous Cultivation ◽  
Clay Soils ◽  
Size Fractionation ◽  
Particle Size Fractionation ◽  
Low Activity

The objectives of this work were: (i) to study the acid monophosphoesterase activity (pH 6.5) of the surface horizons of low-activity tropical clay soils (West Africa, West Indies, Brazil), cultivated or uncultivated, with widely different textures and organic matter (OM) contents, (ii) to measure the phosphatase activity (Pase) in the organic and organo-mineral soil fractions obtained by particle size fractionation. Pase was most significantly correlated to the soil OM content and to a lesser extent to the texture and total P content. Therefore, any modification in soil management resulting in important changes in soil OM contents, leads to important variations in phosphatase activity: Pase decreases after clearing of the native vegetation and continuous cultivation, Pase increase when grass-fallows or meadows succeed to annual cropping. The Pase of all the size fractions (20–2000 μm, 2–20 μm and 0–2 μm) was controled by their OM content. However, the "potential Pase" defined as the ratio Pase/C was higher in the 20- to 2000-μm and 0- to 2-μm fractions than in the 2–20 μm ones This is attributed to a higher Pase renewal by root restitutions in the plant debris fraction (20–2000 μm) and by microbial activity and microbial metabolites in the organo-clay fraction (0–2 μm). More than 50% of the soil total Pase was associated with fractions coarser than 2 μm. Most of the changes in Pase (75–100%) associated with the cultivation were ascribed to these fractions. This illustrate the probably important role of the fractions coarser than 2 μm in the phosphorus dynamics in these soils. Key words: Phosphomonoesterase, organic matter, particle size fractionation, low-activity tropical clay soils

Pouvoir fixateur vis-à-vis des ions phosphate de sols tropicaux à argile 1:1

1992 ◽  
Vol 72 (2) ◽  
pp. 135-143 ◽  
Author(s):  
E. Frossard ◽  
M. Brossard ◽  
C. Feller ◽  
J. Rouiller
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Mineralogical Composition ◽  
Clay Soils ◽  
Exchange Method ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Particle Size Fractionation ◽  
Low Activity

This study was aimed to clarify the influence of secondary mineral constituents (iron and aluminium oxides, kaolinite) and organic matter on the determination of the phosphate-fixing capacity (PFIX) of well-drained low-activity clay soils. This study was done on soil samples (0–2 mm) and on their particle size fractions. The phosphate-fixing capacity, estimated by an isotopic exchange method, was highly related to the total iron content of the soils. The phosphate-fixing capacity of the particle size fractions was related to their mineralogical composition, and to the organisation of their constituents. H2O2 strongly increased the phosphate-fixing capacity of the soils and of their particle size fractions. Two hypotheses were proposed to explain this. Either H2O2 caused the formation in vitro of amorphous constituents with a high phosphate fixing capacity; or the destruction of organic matter by H2O2 caused the apparition of new surfaces previously masked by organo-mineral aggregation and/or caused the apparition on surfaces of fixation sites previously occupied by organic compounds. Key words: Phosphate-fixing capacity, low-activity clay soils, particle size fractionation, mineralogy, organic matter, H2O2 effect

A routine method to study soil organic matter by particle‐size fractionation: Examples for tropical soils

1995 ◽  
Vol 26 (11-12) ◽  
pp. 1749-1760 ◽  
Author(s):  
E. Gavinelli ◽  
C. Feller ◽  
M.C. Larré‐Larrouy ◽  
B. Bacye ◽  
N. Djegui ◽  
...  
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Tropical Soils ◽  
Routine Method ◽  
Size Fractionation ◽  
Particle Size Fractionation

Using a sequential density and particle-size fractionation to evaluate carbon and nitrogen storage in the profile of tilled and no-till soils in eastern Canada

2009 ◽  
Vol 89 (3) ◽  
pp. 255-267 ◽  
Author(s):  
E G Gregorich ◽  
M R Carter ◽  
D A Angers ◽  
C F Drury
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Prince Edward Island ◽  
Sandy Loam ◽  
Soil Tillage ◽  
Size Fractionation ◽  
Eastern Canada ◽  
No Till ◽  
Particle Size Fractionation ◽  
C And N

Tillage influences the retention and storage of organic matter (OM) in soil. We used a sequential density and particle-size fractionation to evaluate the total quantity and distribution of organic carbon (C) and nitrogen (N) in the profile of soils under mouldboard ploughing and no-till. Cores (0-60 cm) from four long-term tillage studies (in Prince Edward Island, Quebec, and two sites in Ontario) on soils of different textures, from sandy loam to clay were collected and divided into six depth increments. Four soil OM fractions were isolated on the basis of size and density from each sample. At two sites the standing stocks of C and N were larger in tilled than in no-till soil profiles at depths slightly greater than plough depth; tillage effects were also evident at a third site, where the mass of C in a layer close to the depth of ploughing was greater in tilled soils. Ploughing also had a substantial and consistent positive effect in all four soils on the quantity of C (and in some cases N) protected within aggregates, particularly at or near the bottom of the plough layer, and sometimes in surface soil layers. We attribute differences observed in whole soil C and N due to tillage mostly to differences in mineral-associated OM, particularly in soils with heavier textures, but the other size and density fractions could, together, account for as much as 25% of the difference. Because the C capacity level was not reached in heavy-textured soils, these soils show greater potential for further accumulation of C in the soil profile than coarse-textured soils, especially near the bottom of the plough layer.Key words: Light fraction, soil organic matter, soil tillage, physically-protected organic matter, no-till, soil texture

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