José Henrique da Silva
Abstract:
In the Chapadões region, Goiás state, the microrelevels in marshy fields, or murundus fields, also called covais, cocorutos, morrotes and monchões, constitute extensive areas where the Haplic Plintosols predominate. Many of these areas have been incorporated into agricultural production systems without impacts on physical and water characteristics being assessed. Thus, the aim of this work was to evaluate the impact of chronosequence of agricultural use on soil water movement in the murundus field through the following parameters: hydraulic conductivity, infiltration velocity and soil penetration resistance. Also evaluate the performance between the infiltration values obtained in the field and the values calculated through the Kostiakov, Horton and Kostiakov-Lewis empirical models for the infiltration tests. For this, four areas were selected, of which three are under the chronological sequence of agricultural use and one fully preserved area. For the determination of the infiltration velocity, an infiltrometer cylinder was used, for the hydraulic conductivity the constant load permeameter and for the penetration resistance of the soil the penetrograph was used. In the preserved areas, basic infiltration velocity values of 242 and 170 mmh-1 were obtained for the low and high parts of the murundus, respectively, and values of 2 mmh-1 for the areas with agricultural use. Hydraulic conductivity values were 42.33 cmh-¹, 12.97 cmh-¹, 13.95 cmh-¹, 13.38 cmh-¹ and 5.79 cmh-¹ respectively for the upper and lower parts of the murundus, five, ten and fifteen years of agricultural use. The soil penetration resistance tests (RSP) showed that in the preserved area the lowest values of RSP occurred; 0.73 Mpa in the upper part and 0.80 Mpa in the lower part of murundus, the highest values were found in the areas with fifteen, ten and five years of agricultural use, respectively 6.62, 5.78 and 3.95 Mpa. It was observed a reduction of the structural quality evaluated by the hydraulic conductivity, basic infiltration speed and soil penetration resistance to the area with anthropic interference in no-tillage system.
