Qualidade do solo influenciada pela aplicação de biocarvão e calcário.

Abstract

The application of conditioners in cultivated lands can contribute, through the improvement of the quality of the physical and chemical attributes, so that the soil performs more efficiently, the functions that promote the development of plants. The general objective of this thesis was to evaluate whether the application of eucalyptus biochar and dolomitic limestone effectively act as conditioners for the quality of soils cultivated with eucalyptus and grains. In order to achieve the objectives, two field experiments were carried out: i) in RED YELLOW OXISOL cultivated with eucalyptus, in São Jerônimo da Serra, northern Paraná; and, ii) in HÁPLIC DYSTRUDEPT used for the production of grains, in Irati, Center-South of Paraná. In the Oxisol, the treatments evaluated were two textural classes (clay and sandy clay loam) and two doses of eucalyptus biochar (0 Mg ha-1 and 3.21 Mg ha-1 ). The treatments evaluated in Dystrudept were: without lime application – 0 Mg ha-1 limestone and; with application of limestone; and, three forms of incorporation of the corrective: without incorporation of limestone (WI), incorporation of limestone with a plow and leveling harrow (IPLH) and incorporation of limestone with a scarifier and leveling harrow (ISLH). The treatment with limestone application represents the dose of limestone needed to raise the base saturation to approximately 70%. Several soil attributes were evaluated in the two studies: soil bulk density (BD), total porosity (TP), macroporosity (Macro), microporosity (Micro), field capacity (FC), permanent wilting point (PWP), available water contente (AWC), soil water storage capacity (SWSC), soil aeration capacity (SAC), soil resistance at potentials of – 6 and – 10 kPa (PR6 and PR10, respectively). In Dystrudept were also evaluated pH, Al3+, Ca2+, Mg2+ and organic carbon (OC). In the Oxisol, the results obtained demonstrate that, for the two textural classes evaluated, the biochar altered the distribution of soil pores, reduced BD, FC, SWSC, increased TP and SAC. In the clay Oxisol, biochar was found to significantly reduce PR6 and PR10. In Dystrudept, limestone promoted an increase in BD, PR6 and PWP. In the WI treatment, there was an increase in BD, PWP and PR10 and, in the ISLH, an increase in pH. There were effects of the interaction between limestone and the forms of incorporation only for TP and K+ . In IPLH, the application of lime reduced TP. In the WI treatment, the application of lime contributed to the increase of K+ contents, while in IPLH there was a reduction. Limestone application increased K+ levels in ISLH. It was concluded that biochar was effective as a physical conditioner of the studied Red-Yellow Oxisol, improving its quality for plant development. In Dystrudept, the application of lime contributed significantly to the improvement of chemical attributes, but negatively affected the physical quality of the soil.