Physical quality indexes for a Cambisol in management systems

• Autor(a) principal: Alcione GuimarÃes Freire
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFC
• Texto Completo: http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=8141
• topic: qualidade do solo; Chapada do Apodi; continuidade de poros; AGRONOMIA

The Apodi Tableland has emerged as a promising pole of irrigated fruit because of the agricultural potential of its soils. Soils of Apodi Tableland are subjected to different types of management, thus conditioning changes in their physical attributes. This work aims to evaluate physically a Cambisol cultivated with papaya (Carica papaya L.) under two tillage systems, compared to another under secondary forest. Soil samples with disturbed and undisturbed structure were collected for physical analysis, namely: texture, clay dispersed in water, bulk density, particle density, aggregate stability, organic carbon, soil water retention curve, soil air permeability and soil resistance to penetration. Clay flocculation degree, soil porosity and indices related to porous geometry and organic matter were calculated. A soil water infiltration test was performed at field. The factorial scheme was 3x3x5 (two soil management systems â papaya planted on furrow and ridge â and secondary forest; three soil layers â 0-0.1 m; 0.1-0.2 m, 0.2-0.3 m; five replications), conducted in a completely randomized design, except for the hydraulic conductivity, which adopted a factorial scheme 3x2x5 (two soil management systems and secondary forest; two tensions â 0 hPa and 5 hPa, five replications). The Kolmorogov-Smirnov Test was used to verify the data set normality, the F Test for variance analysis, the Tukey Test for means comparison (all using p-value = 0.05) and multivariate analysis techniques. It was concluded that: a) the hipothesis that the tillage systems physically worsen soil was refuted, indicating that the quality of the attributes of cultivated soil, in general, has been maintained or improved in relation to the status of the native soil; b) the decreases of the organic matter content, percentage of stable aggregates in the diameter class of 4.76 to 2.00 mm and the average diameter on the cultivated soil, although they are still far from critical limits, are indicative of the need for adoption of management practices that avoid triggering a soil degradation process; c) the quality indices were sensitive to changes caused by soil tillage systems and therefore can be used as a source for understanding the dynamics of soil physical processes in time; d) the proposed indicator for evaluating soil physical quality, Srelative, was sensitive to measure the soil response to the action on its structure.