Propriedades químicas de um Argissolo Amarelo sob sistema convencional e plantio direto na Amazônia Ocidental

Abstract

The development of sustainable agricultural systems in the Western Amazon in areas resulting from the suppression of native forest is a key factor for maintaining and improving the physical, chemical and biological quality of its soils and environmental quality. In this context, the objective of this study was to evaluate the chemical quality of a Yellow Acrisol in a conventional (PC) and no-tillage (PD) system. The experiment was implemented in a split plot design in randomized blocks, with three blocks, in the main plots are the PC and the PD and in the subplots are the 5 treatments: ACQ-conventional land use mode in the region; LG with cover plant; LGP-with cover plant and with phosphate fertilization; LGC-with cover plant, with limestone and without fertilization and LGPC-with cover plant, with limestone and with phosphorus fertilization. The pH in H2O and KCl were evaluated; the basic cations Ca2+, Mg2+, K+ ; the Al3+; the P, the micronutrients Zn and Mn and the contents of organic carbon and organic nitrogen in the depths from 0 to 5; 5 to 10; 10 to 15; 15 to 20; 20 to 40 and 40 to 60 cm, respectively. There was no effect of PD in relation to PC on active acidity (pH); in the K+ contents; Mn; Zn; CO and NO, however, PD increased the levels of Ca2+ and Mg2+ and reduced the levels of Al3+ in the LGPC treatment, mainly up to a depth of 17.5 cm. In addition, the LGPC treatment improved the chemical quality of the Argisol, increasing the pH values, base saturation, electronegativity and reducing Al3+ contents in relation to ACQ. These results indicate that conservation management improves soil chemical quality in relation to conventional land use cultivation in this region, being an important tool in increasing crop productivity and environmental conservation. KEYWORDS: ground cover; soil conservation; crop rotation; management system