INVESTIGADORES
BUSCHIAZZO Daniel Eduardo
artículos
Título:
Organic matter accumulation in size fractions of soils of the semiarid Argentina. Effects of climate, soil texture and management
Autor/es:
HEVIA, G.; BUSCHIAZZO, D.E.; HEPPER, E.; URIOSTE, A.; ANTON, L.
Revista:
GEODERMA
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2003 vol. 116 p. 265 - 277
ISSN:
0016-7061
Resumen:
Soil organic matter contents (SOM) of soils of the Semiarid Pampas of Argentina (SAP), mostly
Entic Haplustolls, increase with the amount of silt + clay, but it is still not known how soil texture
affects its qualitative composition in interaction with climatic and management conditions. Because
of that the organic matter content of the following aggregate size fractions were determined: < 2000
Am (SOM), 1002000 Am (YOM), < 100 Am (HOM), water floatable organic matter (FOM), and
the E4/E6 quotient. These fractions were studied in the 20-cm topsoils of seven REFERENCE
(virgin Caldenal savanna-like soils), and 10 CULTIVATED soils (under continuous conventional
tillage since more than 50 years). Results showed that SOM of both REFERENCE and
CULTIVATED soils was mainly composed by YOM (57%), and to a lesser extent by HOM
(37%) and FOM (5%). Silt + clay conditioned positively the contents of SOM, YOM and HOM of
both REFERENCE (R2 = 0.18, R2 = 0.21, R2 = 0.21, respectively, n = 21, p < 0.05) and CULTIVATED
soils (R2= 0.62, R2= 0.44, R2 = 0.52, respectively, n= 30, p < 0.001). The positive
fulvic acids exist in the well humified organic fraction of the studied soils. Contents of FOM and E4/
E6 values did not correlated with the climatic conditions nor with soil texture or management.
Potential SOM losses can be larger in fine-textured soils (up to 54.3 Mg C ha 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid inrelationship existing between silt + clay and both SOM and YOM seems to be not longer valid in
sites with mean annual temperatures (MAT) higher than 17 jC. YOM and HOM accumulation were
positively affected by precipitation and negatively by temperature in combination with silt + clay.
This effect was more pronounced for HOM. The slopes of the regressions between SOM, HOM and
YOM with silt + clay were more pronounced for REFERENCE soils than for CULTIVATED soils,
indicating the largest absolute losses of these organic matter fractions in fine- rather than in coarsetextured
soils. E4/E6 quotients were lower than 5 in all studied soils indicating that humic rather thanm (SOM), 1002000 Am (YOM), < 100 Am (HOM), water floatable organic matter (FOM), and
the E4/E6 quotient. These fractions were studied in the 20-cm topsoils of seven REFERENCE
(virgin Caldenal savanna-like soils), and 10 CULTIVATED soils (under continuous conventional
tillage since more than 50 years). Results showed that SOM of both REFERENCE and
CULTIVATED soils was mainly composed by YOM (57%), and to a lesser extent by HOM
(37%) and FOM (5%). Silt + clay conditioned positively the contents of SOM, YOM and HOM of
both REFERENCE (R2 = 0.18, R2 = 0.21, R2 = 0.21, respectively, n = 21, p < 0.05) and CULTIVATED
soils (R2= 0.62, R2= 0.44, R2 = 0.52, respectively, n= 30, p < 0.001). The positive
fulvic acids exist in the well humified organic fraction of the studied soils. Contents of FOM and E4/
E6 values did not correlated with the climatic conditions nor with soil texture or management.
Potential SOM losses can be larger in fine-textured soils (up to 54.3 Mg C ha 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid inrelationship existing between silt + clay and both SOM and YOM seems to be not longer valid in
sites with mean annual temperatures (MAT) higher than 17 jC. YOM and HOM accumulation were
positively affected by precipitation and negatively by temperature in combination with silt + clay.
This effect was more pronounced for HOM. The slopes of the regressions between SOM, HOM and
YOM with silt + clay were more pronounced for REFERENCE soils than for CULTIVATED soils,
indicating the largest absolute losses of these organic matter fractions in fine- rather than in coarsetextured
soils. E4/E6 quotients were lower than 5 in all studied soils indicating that humic rather thanCaldenal savanna-like soils), and 10 CULTIVATED soils (under continuous conventional
tillage since more than 50 years). Results showed that SOM of both REFERENCE and
CULTIVATED soils was mainly composed by YOM (57%), and to a lesser extent by HOM
(37%) and FOM (5%). Silt + clay conditioned positively the contents of SOM, YOM and HOM of
both REFERENCE (R2 = 0.18, R2 = 0.21, R2 = 0.21, respectively, n = 21, p < 0.05) and CULTIVATED
soils (R2= 0.62, R2= 0.44, R2 = 0.52, respectively, n= 30, p < 0.001). The positive
fulvic acids exist in the well humified organic fraction of the studied soils. Contents of FOM and E4/
E6 values did not correlated with the climatic conditions nor with soil texture or management.
Potential SOM losses can be larger in fine-textured soils (up to 54.3 Mg C ha 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid inrelationship existing between silt + clay and both SOM and YOM seems to be not longer valid in
sites with mean annual temperatures (MAT) higher than 17 jC. YOM and HOM accumulation were
positively affected by precipitation and negatively by temperature in combination with silt + clay.
This effect was more pronounced for HOM. The slopes of the regressions between SOM, HOM and
YOM with silt + clay were more pronounced for REFERENCE soils than for CULTIVATED soils,
indicating the largest absolute losses of these organic matter fractions in fine- rather than in coarsetextured
soils. E4/E6 quotients were lower than 5 in all studied soils indicating that humic rather thanR2 = 0.18, R2 = 0.21, R2 = 0.21, respectively, n = 21, p < 0.05) and CULTIVATED
soils (R2= 0.62, R2= 0.44, R2 = 0.52, respectively, n= 30, p < 0.001). The positive
fulvic acids exist in the well humified organic fraction of the studied soils. Contents of FOM and E4/
E6 values did not correlated with the climatic conditions nor with soil texture or management.
Potential SOM losses can be larger in fine-textured soils (up to 54.3 Mg C ha 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid inrelationship existing between silt + clay and both SOM and YOM seems to be not longer valid in
sites with mean annual temperatures (MAT) higher than 17 jC. YOM and HOM accumulation were
positively affected by precipitation and negatively by temperature in combination with silt + clay.
This effect was more pronounced for HOM. The slopes of the regressions between SOM, HOM and
YOM with silt + clay were more pronounced for REFERENCE soils than for CULTIVATED soils,
indicating the largest absolute losses of these organic matter fractions in fine- rather than in coarsetextured
soils. E4/E6 quotients were lower than 5 in all studied soils indicating that humic rather thanR2= 0.62, R2= 0.44, R2 = 0.52, respectively, n= 30, p < 0.001). The positive
fulvic acids exist in the well humified organic fraction of the studied soils. Contents of FOM and E4/
E6 values did not correlated with the climatic conditions nor with soil texture or management.
Potential SOM losses can be larger in fine-textured soils (up to 54.3 Mg C ha 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1) than in coarsetextured
(up to 35.7 Mg C ha 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid in 1). Probable changes of soil texture by wind erosion will modify
absolute contents of SOM, YOM and HOM, while modifications of temperature or rains regimes will
affect HOM more. relationship existing between silt + clay and both SOM and YOM seems to be not longer valid inrelationship existing between silt + clay and both SOM and YOM seems to be not longer valid in
sites with mean annual temperatures (MAT) higher than 17 jC. YOM and HOM accumulation were
positively affected by precipitation and negatively by temperature in combination with silt + clay.
This effect was more pronounced for HOM. The slopes of the regressions between SOM, HOM and
YOM with silt + clay were more pronounced for REFERENCE soils than for CULTIVATED soils,
indicating the largest absolute losses of these organic matter fractions in fine- rather than in coarsetextured
soils. E4/E6 quotients were lower than 5 in all studied soils indicating that humic rather thanjC. YOM and HOM accumulation were
positively affected by precipitation and negatively by temperature in combination with silt + clay.
This effect was more pronounced for HOM. The slopes of the regressions between SOM, HOM and
YOM with silt + clay were more pronounced for REFERENCE soils than for CULTIVATED soils,
indicating the largest absolute losses of these organic matter fractions in fine- rather than in coarsetextured
soils. E4/E6 quotients were lower than 5 in all studied soils indicating that humic rather than