Dosagem de macronutrientes selecionados em solos de terra firme de Caxiuanã

Abstract

The soils of the Caxiuanã region are differentiated by their outstanding physical and chemical properties related to the ecosystem of the region. The aim of this work was to assist in the generation and analysis of data concerning the chemical and physical-chemical components of the soils of the LBA/Caxiuanã-PA project. The soil samples were collected at three points in the Caxiuanã area: sites A and B (plots of the ESECAFLOR-LBA experiment) and T (LBA project tower), which are classified as yellow Latosol and present a sequence of A, AB, BA and B horizons. The soils at sites A and B are sandy in texture and well drained. The soil from site T is clayey and moderately drained. The analyses were collected in two seasonal periods: the first at the beginning of the dry season and the second at the beginning of the rainy season. In the first seasonal period (dry period), the pH values, both in water and in KCl, in sites A and B were higher than in the second period. The pH values in both water and KCl were higher in sites A and B than in the second period, thus characterizing a lower acidity compared to the soils analyzed during the rainy season. In site T, there was a decrease in acidity from the dry period to the rainy period. Regarding the macronutrients, the contents remained stable, in both periods, in all sites, with the exception of the AI content, which decreased in the second seasonal period. A comparison between the seasonal periods allows us to conclude that the higher the soil moisture, the lower the acidity and the lower the available exchangeable AI3+ content in the soil.