Dissertations and Theses

Summary

The southern region of Maranhão is the largest producer of grains mainly soybeans and corn, contributing significantly to the economy, with a production of 55.8%. The characterization and variability of the soil attributes of this region becomes important for a better understanding of soil pedogenic processes, and the use of better management practices, providing a higher productivity in a sustainable way. Through tools such as statistics and geostatistics, it is possible to understand the relationship between soil attributes and landscape forms, indicating the spatial variability of the attributes of the region. Thus, the present work had as objective the characterization and variability of the attributes of the soils of the semi - arid south of Maranhão, São Raimundo das Mangabeiras municipality. A total of 94 samples were collected at 0 - 0.20 m depth, at a spacing of 200 x 200 m, and six soil profiles were selected and classified. Granulometric analyzes were done (sand, silt, clay and sand fractionation); (quantities of bases, phosphorus, organic matter and pH); mineralogical (quantification of iron oxides, kaolinite and gibbsite); and magnetic and spectral analyzes. The data were submitted to descriptive statistics analyzes and geostatistical analyzes by simple kriging. The study of the profiles and samples were divided according to three compartments of the landscape: concave-linear, concave and convex-concave. The soils classified were Dystrophic Yellow Red Latosol (LVAd), Dystrophic Haplic Plinthsol (FXd), Dystrophic Yellow Latosol (LAd), Eutrophic Yellow Red Latosol (LVAe), Eutrophic Red Latosol (LVe) and Dystrophic Yellow Latosol (LAdp). Among the compartments analyzed, the one that presented the highest coefficient of variation was the compartment I, where the soil was found with emphasis on higher fertility, and the concave-linear pedoform provided greater spatial variability especially of the clay fraction, demonstrating that the shape of the relief conditions patterns variability. The granulometry presented low variation. However, the P and SB attributes varied in the range of 3.26 to 5.16 mg dm-3 and 10.42 to 33.51 mmolc dm-3 , respectively, and were expressed in spatial attribute maps.