Aggregation and structural vulnerability coefficient of an Oxisol under no-tillage and nitrogen and potassium fertilization

Abstract

The tropical Oxisold are generally well aggregated, however, in recent years there has been an agricultural intensification of these soils due to the global demand for fibers and proteins. The objective of this work was to evaluate the aggregation and structural vulnerability coefficient of a Latosol under no-tillage system submitted to nitrogen and potassium fertilization. The treatments were arranged in a factorial scheme according to the Plan Puebla III matrix, resulting from the combination of five doses of Nitrogen (N) in the form of Urea (5; 30; 50; 70 e 95 kg ha^-1) and five doses of potassium (K), as KCl (4; 24; 40; 56 e 76 kg ha^-1), plus the control (without fertilization). Soil samples were collected in layers 0-10 and 10-20 cm deep. Soil aggregation was determined by sorting and sorting through the weighted average diameter of dry and wet aggregates. The experimental units were granulometry, soil density and porosity. The highest values f dry macroaggregates in the 0-10 cm layer were 90.8 and 92.5%, for line and interlining, respectively. For a 10-20 cm layer, the highest value in the line of 92.1% and 92.6% in the interline. It is concluded that the system of no-till use and the combination of nitrogen and potassium fertilization do not alter the stability of the aggregates.