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Diagnóstico de limitaciones físicas en inceptisoles de los llanos occidentales venezolanos

Bioagro, ISSN 1316-3361, Vol. 12, Nº. 1, 2000, pags. 15-24
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Available from: Deyanira Lobo, May 24, 2014
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    ABSTRACT: The combination of deforestation due to agricultural frontier expansion and the increased use of fertilizers due to agricultural intensification has lead to an increase in the load of sediments and pollutants that negatively affect water quality in rural areas. This problem is particularly serious in the Colombian Andean region. This study applies a hydrological simulation model to compare the effect of four vegetable coverage management scenarios on nutrient migration from agricultural practices in the Upper Magdalena river basin. The simulation of water movement over hillsides and channels, which was run using the MIKE SHE and MIKE 11 models, showed an acceptable performance (S/ σΔ =0.84, R=0.82, R2=0.67). However, pollutant migration showed a very low sensitivity to vegetable coverage in the configuration of the different model simulations (p > 0.05), with reductions in pollutant loads ranging only between 2 and 4%. Such reductions have to do with the intrinsic properties of vegetation (which act like a barrier to sediment flow,) with its ability to increase soil infiltration (therefore reducing runoff,) and with nutrient absorption by plants.
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    ABSTRACT: In order to evaluate soil susceptibility to physical degradation, four Alfisol soils from the Western and Central Plains were selected and identified as: Barinas, Chaguarama 1, Chaguarama 2, and Chaguarama 3. Research was conducted mainly in field and complementary evaluations were made at the laboratory, based on simple measurements, taking into account the dynamic nature of soil properties. Soil infiltration, bulk density, penetrometer resistance, moisture content, hydraulic conductivity, infiltration through seal, and field capacity were measured in field. Particles' size distribution, wet aggregate size distribution, sealing indices, consistency limits, total porosity, air porosity, cohesion in dry conditions and pore size distribution in each one of the identified soil layers were determined at the laboratory. The evaluation showed that soils have low structural stability and tendency to compactness, due to the particles' size distribution, which affects soil hydrological properties, their susceptibility to erosion and resistance to tillage and root penetration.
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    [Show abstract] [Hide abstract]
    ABSTRACT: The combination of deforestation due to agricultural frontier expansion and the increased use of fertilizers due to agricultural intensification has lead to an increase in the load of sediments and pollutants that negatively affect water quality in rural areas. This problem is particularly serious in the Colombian Andean region. This study applies a hydrological simulation model to compare the effect of four vegetable coverage management scenarios on nutrient migration from agricultural practices in the Upper Magdalena river basin. The simulation of water movement over hillsides and channels, which was run using the MIKE SHE and MIKE 11 models, showed an acceptable performance (S/σΔ=0.84, R=0.82, R2=0.67). However, pollutant migration showed a very low sensitivity to vegetable coverage in the configuration of the different model simulations (p ≥ 0.05), with reductions in pollutant loads ranging only between 2 and 4%. Such reductions have to do with the intrinsic properties of vegetation (which act like a barrier to sediment flow,) with its ability to increase soil infiltration (therefore reducing runoff,) and with nutrient absorption by plants.
    07/2009; 13(2):341-369.