Atributos físicos e químicos após incubação com ácidos húmicos e esteárico em neossolos flúvicos

• Autor(a) principal: Miranda, Márcio Fléquisson Alves
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5426
• topic: Solos salino-sódicos; Matério orgânica; Agregados no solo; Saline-sodic soil; Organic matter; Soil aggregates; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO

This study aimed to evaluate the effect of addition of compounds of varying hydrophobicity on physycal and chemical quality of soils of the brazilian Northeast, particularly as regards distribution and aggregate stability and chemical composition and soil-water extract 1:5. For this, two experiments were conducted on samples collected from two Neossoils Fluvic ( RY1 = normal soil, RY2 = saline-sodic soil) at depths of 0 to 20 cm and 20 to 40 cm in irrigated waterfall II, located in Serra Talhada (PE). At firs, we evaluated the response of soils to increase the incubation time (40, 80 e 150 days) after the application of humic acid and stearic acid in a single dose of 5,0 g Kg-1. The second experiment evaluated the response of soil after the addition of increasing doses (0; 2,5; 5,0; 7,5 e 10,0 g Kg-1) of organic compounds, after an incubation period of 150 days. All tests were conducted for samples from two depths and three repetitions. We evaluated the average diameter and geometric weighted, after separation of aggregates by dry and wet, clay dispersed in water, equivalent moisture, cations ( Ca, Mg, Na and K) in soil and extract soil-water (1:5), in addition to electrical conductivity (EC), pH and RAS in the extract and PST on the soil. In the first experiment, the results indicated positive effect of increasing the incubation period of the genesis and growth of the average diameter of the aggregates. In the comparation between organic compounds, the effects were more significant with the stearic acid. Comparing soil, the same effects were more pronounced in saline-sodic soil. The increase of incubation time favored a small increase in dispersion of clay, which was related to the increase of negative charges provided by the organic matter added. The results of the extract soil: water were influenced by the presence of salts in the humic acid used, which promoted the increase of electrical conductivity and some soluble cations, especially Na. There were no differences between incubation times evaluated on the chemical characteristics of soils. The increasing levels of organic compounds also favored the formation positively and the average diameter of aggregates, mainly in the 0 to 20 cm depth. The stearic acid was again more effective in this aspect. The increasing levels of humic acid affect some of the chemical variables measured in the soil RY1, being more closely related to the prior salts in organic material. The addition of stearic acid had little influence on the chemical found in two soils. The results indicated that the application of stearic acid (more hydrophobic) promotes soil aggregation, with the potential that deserves to be evaluated under field conditions for salt affected soils; the effect of adding organic compounds was more pronounced on the physical characteristics than on the chemical characteristics of soil and extract; and that once again highlights the important role of organic matter in ensuring the quality of the soil physical structure, with the potential still unexplored in terms of their effects on soils affected by salts.