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Revista Ciencia del Suelo

 2007 / Diciembre / Volumen 25 N.2

 

Transformaciones de fósforo en un Molisol bajo sistemas de labranza contrastantes.


(Phosphorus transformations in a mollisol under contrasting tillage practices)
Picone L, I Capozzi, E Zamuner, H Echeverria & H Sainz Rozas.
Pág. 99-107
Resumen | Texto en pdf


Conservation tillage may affect soil phosphorus (P) fractions through the application of P fertilizer and the deposition of residue on the soil surface. The objectives were to 1) evaluate the effect of tillage systems on soil P fractions, as well as the interaction with P fertilization, and 2) relate changes in P fractions with P balance. No tillage and conventional tillage were assigned as main plots and the two P rates (0 y 30 kg P ha-1) the subplots, with three replicates. Inorganic (Pi) and organic (Po) P were measure with the anion exchange membrane (AEM), NaHCO3, NaOH, HCl and residual fractions, extracted sequentially. When the amount of P applied exceeded that removed by grain, the P excess was converted to different fractions, but with no increases in Bray-P compared to initial value. In the short time, there was no interaction neither significant effect of tillage systems on Pi forms; however, the AEM-Pi and NaHCO3-Pi fractions were significantly (p< 0,05) higher with P application. Without consideration of residual-P and among the inorganic forms, the HCl-Pi showed high values, in absolute (50 mg P kg-1) and relative (9% of total P) terms, according to geochemical characteristics of these soils. There was no interaction of fertilizer application with tillage neither main effects on Po fractions. Among all P fractions, NaOH-Po was the most abundant (186,7 mg P kg-1 and 34% of total P), followed by residual-P. In agreement with the positive P balance, total P tended to be higher with P application and the sum of fractions extracted by AEM, NaHCO3, NaOH y HCl accounted, on average, for 81% of the increment in total P.

 

Movimiento del agua en Argiudoles de la Pampa Ondulada con diferente mineralogía de arcillas.


(Water movement in some argiudolls of the rolling Pampa differing in their clay mineralogy)
Castiglioni MG, HJM Morrás, OJ Santanatoglia, MV Altinier & D Tessier.
Pág. 109-121
Resumen | Texto en pdf


Typic and Vertic Argiudolls, which differ in the composition of their clay fraction, are the zonal soils in the Rolling Pampa of Argentina. The aim of this work has been to analize the relationship between water movement and diverse soil properties in some representative soils of the Rolling Pampa, differing in their clay mineralogy. The A, BA/ BE, Bt and BC horizons of two Typic and one Vertic Argiudolls were sampled and a number of properties related with clay content and clay type were measured. Soil porosity and soil water movement were also evaluated through different techniques. In the Bt horizons, those parameters integrating clay type together with clay content, as COLE and CEC, have shown a better relationship with soil water movement than considering clay quantity alone. Clods from Bt horizons of studied soils have shown to differ in their internal structural porosity and this led to different diffusivity and unsaturated (at 50% water holding capacity) hydraulic conductivity results. In upper soil horizons, characterized by a lower clay content and a greater biological activity, water movement was not related to clay mineralogy.

 

Modelos de infiltración y funciones de pedotransferencia aplicados a suelos con distinta textura.

(nfiltration models and pedotransfer functions applied to soils with different texture)
Landini AM, D Martinez, H Días, E Soza, D Agnes & C Sainato.
Pág. 123-131.

Resumen | Texto en pdf


The knowledge of the process of water infiltration in soil is important in the design of irrigation systems and in the prediction of the vulnerability to the contamination of soil and groundwater. Moreover, it is important to evaluate the efficiency of the hydrological models that predict the movement of water in soil. The objective of this study was to evaluate and to compare the goodness of fitting of Kostiakov-Lewis (K-L) and Philip (Ph) infiltration models to experimental data obtained from three soils: two of them at the Province of Buenos Aires, and the third one at the School of Agronomy’s campus of the Buenos Aires University, (Argentina). Efficiency of Saxton and Rawls (SyR) pedotransfer functions (FPT) on the determination of the Green and Ampt (GA) model input hydraulic parameters and the prediction of the soil-moisture release curve were analyzed too. K-L and Ph models fitted data with R2 coefficient greater than 0.6. Then it was concluded that these models accurately describe the infiltration process of the studied soils. The highest basic infiltration rate (fo) was 0.42 cm min-1 and corresponded to a silty clay soil with organic amendment, and for the other two soils (silt loam and clay loam) were 0.03 and 0.07 cm min-1 respectively. For two of the studied soils, GA model obtained from input parameters determined with the FPT, predicted the infiltration process with an efficiency coefficient (CE) greater than 0.8. However, at some cases, the fitting was not so good for dephts greater than 20 cm. For the silt loam soil, the FPT predicted the soil-moisture release curve with an CE close to 0.9. It might be suggested to carry out a preliminary few number of infiltration tests on any soil under study, and analyze the FPT and the GA model goodness of fit. In this way, the convenience of using these models could be evaluated.

 

Forty years of soil degradation in vertic Argiudols in Entre Ríos Province, Argentina.

(Cuarenta años de degradación de argiudoles vérticos en la provincia de Entre Ríos)
Cosentino DJ, ME Conti & L Giuffré. 2007. 25 (2) 133-138.

Resumen | Texto en pdf

 


In the last decade the land use in Entre Ríos Province (Argentina) has suffered a very important increase characterized by an intensive and continuous agriculture in a region with high water erosion susceptibility. Forty percent of province surface suffers water erosion in different degrees. This study was undertaken to assess the extent and nature of degradation in some physical and chemical properties of vertic Argiudolls through the comparison of a pristine situation and three situations with increasing years of land use after deforestation. Organic carbon (OC), light carbon (LC), pH, electrical conductivity (EC), labile organic phosphorus (Plo), structural stability (ΔMWD), size aggregate distribution in the A horizon were determined. After 40 years from deforestation the OC, LC, Plo, decreased 26, 72 and 17% respectively meanwhile EC and pH had minor variations. The structural stability declined with time and there was a significant correlation between organic carbon and ΔMWD (r = - 0.985; P < 0.02; n = 4). Sixty two percent of the A-horizon was lost and as a consequence, 75.5% in carbon sequestration. A mean annual erosion rate of 60 Mg ha-1 yr-1 after 40 years was estimated.

 

Atenuación natural y remediación inducida en suelos contaminados con hidrocarburos.

(Natural attenuation and induced remediation in hydrocarbon polluted soils)
Romaniuk R, JF Brandt, PR Ríos & L Giuffré.
Pág. 139-149

Resumen | Texto en pdf

 


The petroleum derived hydrocarbons represent the main energy source for the humanity and they are in turn, an important environmental polluting source. In this experience it was estimated and compared the rate of decomposition of two hydrocarbons (diesel and crankcase oil), by natural attenuation, and with the incorporation of a specific commercial product in a Typic Argiudoll. The effect of these practices was also evaluated on some soil variables. The treatments were: [control soil without pollution], [soil + gasoil], [soil + crankcase oil], [soil + gasoil + product], [soil + crankcase oil + product], [soil + product]. The soil sampling was carried out in the following series of time [0; 15; 30; 60 and 180 days]. The degradation rate of diesel and crankcase oil hydrocarbons by natural attenuation was slower and less effective than that obtained when adding the commercial product, the latter presented final lower values of Total Petroleum Hydrocarbons. Among the soil variables, the oxidable carbon and the biomass soil respiration registered higher mean values for the polluted soils. The commercial product incorporation produced a significant decrease in these values, an increase in the electric conductivity, but no influence on the pH and the soil extractable phosphorous.

 

Potential universal applicability of soil bioindicators: Evaluation in three temperate ecosystems

(Aplicación potencial universal de bioindicadores del suelo: su evaluación en tres ecosistemas templados)
Gonzalez MG, JF Gallardo, E Gómez, G Masciandaro, B Ceccanti & S Pajares.
Pág. 151-158.

Resumen | Texto en pdf

 


Three selected soils from three countries with temperate climates have been analyzed. Two of the soils are silty loams (Buenos Aires, Argentina, and Salamanca, Spain) and the third one is a sandy loam (Peccioli, Italy). Soil samples representing three agricultural managements were obtained from the top layer (0-10 cm), i.e. intensively cultivated, cultivated and undisturbed native soils. Soil organic carbon (SOC), total nitrogen (Nt), ATP, urease, protease, phosphatase, β-glucosidase, dehydrogenase (DHA), and arginine ammonification (ARA) were determined and compared. SOC and Nt were significantly higher (P < 0.01) in native than in cultivated and intensively cultivated soils. A good correlation (P < 0.05) was found between ATP, hydrolase activities, ARA, and SOC and Nt, indicating that all these parameters were related to the biological properties and biochemical activity. Then, these biological parameters can be used as bioindicators of agriculture-induced changes in soils. DHA did not correlate with the SOC and Nt contents, or protease activities, indicating that the soil ecosystems had low concentrations of exogenous substrates to metabolize and that micro-organisms were in a reduced state of activity.

 

Indicadores de calidad física en suelos de la región Pampeana Norte de Argentina bajo siembra directa.


(Physical quality indicators in soils from the northern Pampa region of Argentina under no till management)
Ferreras L, G Magra, P Besson, E Kovalevski & F García.
Pág. 159-172

Resumen | Texto en pdf



Sustainable land use implies the conservation of soil properties associated both to fertility and tillage. Soil alterations induced by management may affect crop production since management practices influence organic matter distribution and nutrient dynamics, and also soil aggregation and porosity. The Argentinean Northern Pampa is one of the region of the world where soils have been subjected to an intensive agricultural use during the last decades, and where direct drilling has been increasingly adopted. The aim of the present work was to evaluate soil physical quality parameters from agricultural systems under no tillage, in soils representative of the Northern Pampa Region, and to compare them with the same soil type but under pristine condition. A soil physical characterization of plots under cropping was carried out on eleven fields included in the Nutrition Network of CREA Southern Santa Fe, with trials located in Santa Fe, Córdoba and Buenos Aires Provinces. Also, a sampling in an adjacent undisturbed sector with the same soil type was carried out. Soil composite samples were collected at two depths (0-0.08 m and 0.08 m to the lower limit of the Ap horizon). Water and ethanol stable aggregate percentage (Ea and Ee, respectively), total organic carbon (COT), bulk density (DA) and maximum soil density were determined (DMAX). Mechanical resistance (RM) was measured at 0.05 m increments from the soil surface to 0.35 m depth. Soils were clustered in two groups according to their texture: Group I (surface clay content between 215 and 265 g kg-1) and Group II (surface clay content between 98 and 170 g kg-1). Higher values of Ea, Ee and COT were found in both surface and deep layers in the undisturbed soil with respect to cropped soil (p < 0.05). Soils from Group I showed higher Ea, Ee and COT with respect to those from the Group II. Total organic carbon decrease because of management was between 10 and 44%. Direct relationships were found between Ea and COT, and Ee-COT, respectively. Soils from the Group I showed higher levels of Ea than soils from Group II at similar COT contents. Bulk density and DMAX were higher in soils from cropped plots than in the reference undisturbed soils. Soils from the Group I showed, in general, lower DA and DMAX values, at both sampling depths, than those from the Group II. An inverse relationship was found between DMAX and COT. The loss of COT and the structural instability increase soil susceptibility to compaction. The RM from the cropped plots was higher to that from the undisturbed soils, and reached values greater than the limit of 2.0 MPa, at which root growth and fluids supply are affected. Soil indicators of physical fertility that were more sensitive or more informative in this study were Ea and Ee. The analysis of soil structure contributes to understand the effect of external factors on the soil, particularly the anthropogenic ones.

 

Evaluación de la calidad de suelos mediante el uso de indicadores e índices.


(Soil quality evaluation using indicators and indices)
Cantú MP, A Becker, JC Bedano & HF Schiavo.
Pág. 173-178.

Resumen | Texto en pdf

 


The expansion of agriculture in areas with a certain degree of fragility, make it necessary to evaluate the state of soil system by means of indicators. The aim of this paper was to develop and apply a minimum set of indicators of the state of the resource to assess soil quality in agroecosystems with low to moderate development Mollisols. The methodology was tested in a homogeneous environmental unit (with Typic Hapludolls) under different uses and management systems in a piedmont basin in SW Córdoba province. Quality ranges were established for the measured properties (organic carbon, pH, base saturation, water stable aggregates, infiltration rate, bulk density, A horizon depth) to normalize the indicators. Selected indicators constitute a minimum number of variables with a high aggregation degree, easy to measure and repeatable, representing the local conditions. These soil resource state indicators are not universal since they were selected in function of the environment and soil type in the studied region.

 

Comparación de métodos analíticos para la determinación de materia orgánica en suelos de la región Andino-Patagónica: Efectos de la vegetación y tipo de suelo.


(Comparison of analytical methods for determining soil organic matter in Patagonian Andean region: effects of vegetation and soil types)
La Manna L, C Buduba, V Alonso, M Davel, C Puentes & J Irisarri.
Pág. 179-188.

Resumen | Texto en pdf

 


The determination of organic matter (OM) content is key for the knowledge of agricultural and forestry soil productivity. This study evaluated the relationship between OM content determined by weight loss-on ignition (OMWLOI) and Walkley-Black wet oxidation method (OMWO) in soils of the Patagonian Andean Region. The relation was evaluated for volcanic soils with and without amorphous components and with different vegetation types: Pinus ponderosa plantations, herbaceous steppe, shrubly steppe, shrubs and Austrocedrus chilensis forests. One hundred sampling sites were selected and composed samples were obtained from horizon A. Data were analyzed by means of analysis of variance and simple regressions. OMWO was always lower than OMWLOI. This is expectable since OMWLOI includes the total OM, whereas MOWO discriminates the strongly condensed carbon forms. Although differences in the relationship between the analytical methods for soils with and without amorphous components were not detected, a great relationship between these components and organic matter content was found. The relationship between the analytical methods varied according to the vegetation type. Soils with herbaceous steppe and pine plantations presented the greatest differences between the analytical methods. OMWO was in average 37% lower than OMWLOI for these types of vegetation, being significantly greater than soils with srhubs (26%). Soils with Austrocedrus chilensis forests and shrubly steppe presented intermediate values (30% and 35% respectively). Pinus ponderosa plantations (first rotation, average age 21 years) were located in areas with herbaceous steppe. The similarities found between both soils could be associated to the characteristics of OM in the herbaceous steppe environment and soil type, which did not change because of the little time passed since the implantation. Two linear regression models were generated that show the relationship between OMWO and OMWLOI for different vegetation types: Pinus ponderosa plantation and herbaceous steppe OMWLOI (%) = 1.37 x OMWO (%) + 0.81 (R2 = 0.86; n = 40) Shrubs, shrubly steppe and Austrocedrus chilensis forest OMWLOI (%) = 1.19 x OMWO (%) + 1.58 (R2 = 0.93; n = 60) These equations allow the comparison of MO content data generated by different analytical methods.

 

Distribución de nitrógeno, fósforo y azufre en un cultivo de colza: Efectos sobre el ciclado de nutrientes.


(Distribution of nitrogen, phosphorus and sulfur in oilseed rape: effects on nutrient cycling)
Rubio G, JD Scheiner, MA Taboada & RS Lavado.
Pág. 189-194

Resumen | Texto en pdf

 


Oilseed rape poses a higher sulfur (S) demand, compared to other crops. This may indicate that the inclusion of this crop in the crop rotation could accelerate soil S depletion. In this work, we compared the allocation of biomass, nitrogen (N), phosphorus (P) and S in oilseed rape mature plants. Two factors were analyzed in a field experiment: nitrogen and sulphur (two levels for each factor). At harvest, we measured the accumulation of biomass, N, P and S in three compartments: roots, straw and grains. Yield was little affected by the addition of single nutrients but the simultaneous addition of N and S caused a 56% increase in this parameter. Nitrogen and P showed a rather similar allocation pattern. Sulfur, conversely, showed a lower allocation to grains and a higher allocation to straw than the other two studied nutrients. The lower allocation to the harvested organ would attenuate the effect of the high demand of S of this crop on the nutrient balance and would also allow a re-utilization of the S fertilizer by the following crop.

 

Efecto de la severidad del quemado sobre la concentración de carbono orgánico en montículos e intermontículos en el monte Austral.


(Effect of burn severity on the soil organic carbon concentration mounds and intermounds in the monte austral)
Gaitán JJ, DE Bran & F Murray.
Pág. 195-199.

Resumen | Texto en pdf

 


The effect of burn severity on soil organic carbon concentration (COS) in vegetated mounds and in bare soil intermounds was evaluated 4 years after the occurrence of a natural fire in an area of the Monte Austral (Río Negro province). The mounds act as “fertility islands” since COS concentration was higher than in the intermounds. The COS concentration in the intermounds was not affected by fire. On the other hand, in the mounds a decrease in the COS concentration was found when the burn severity increased. The COS loss could induce rangelands degradation, therefore fire management practices should tend to the realization of low severity burns.

 

 


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