Chemical attributes in biogenic and physicogenic aggregates of soil submitted to swine manure application

Abstract

Successive applications of swine manure in soil can promote increases of contents of soil chemical attributes, with emphasis on those present in the biogenic aggregates. The objective of this study was to quantify total organic carbon (TOC), total nitrogen (TN), pH, Al, Ca, Mg, P and K, in the biogenic and physicogenic aggregates of the soil under areas with pig slurry (PS)) and deep litter (DL). After 10 years of use of swine manure in no-tillage system with black oat/maize succession, undisturbed soil samples were collected in the 0-5 and 5-10 cm layers, in the treatments without wastes (control), with application of PS and DL in doses equivalent to one and two times the recommended N for corn and oats (PS1X, PS2X, DL1X and DL2X, respectively). The aggregates were separated according to the biogenic and physicogenic formation pathway, and the chemical analyzes were performed. The application of DL increased the TOC and TN contents in relation to the control and the areas with PS, which did not differentiate between them. The use of PS increased the Ca (0-10 cm), K (PS1X to 0-10 cm) and P (5-10 cm) contents, and did not alter the Mg and TN contents, relative to the control; while the use of DL increased the Mg (0-5 cm), Ca, N, P and K (0-10 cm) when compared to the PS and the control. The biogenic aggregates favor the increase of N, P, K, Mg and TOC in relation to the physicogenic aggregates.