Micromorphometric analysis of aggregates of Rhodic Hapludox under different management systems

The aim of this work is to characterize, using a micromorphometric analysis, the aggregates of a Hapludox submitted to different management systems. This work was carried Out in a Rhodic Hapludox in Dourados-MS. The experimental design was in randomized blocks with four replications and treatments arranged hi sub- subdivided plots. Treatments were established in two management systems (conventional and no-tillage), two doses Of gypsum (zero and 2 t ha(-1)) and the use of two summer crops (soybean and corn). Aggregates were collected, in depths of 0 to 10 and 10 to 20 cm, using, in experimental proceedings, those held in diameter intervals of 9.52 and 4.76 mm, after sieving in a standard sieve set. For collecting aggregates, 40 x 40 cm trenches were opened and sieving was done in the field. Aggregate analyses were done by digital images obtained by scanner (300 dpi) of 60 aggregates arranged in a tray with untidy holes in order to preserve the principle of randomization. Images were later analyzed using the QUANTPORO program, and the analyzed characteristics of the aggregates were the area and its inter-relation with chemical attributes of the soil. The results demonstrated that no-tillage promoted the formation of larger aggregates; soybean as summer culture contributed to that structural effect in the soil; and the application of gypsum increased the aggregation in larger depths.