Dissertations and Theses

PROTOCOL FOR USING SOIL DATA LEGACY FOR THE SOIL MAPPING IN THE SÃO PAULO WEST PLATEAU

Author: Nélida Elizabet Quiñonez Silvero

Keywords: spatial variability, pedometry, soil classification, pedodiversity, soillandscape relationship.

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Summary

Information about the soil resource is scarce in an adequate scale. This information would support the establishment of public policies of its use and management and as well the improvement of the soil maps. This work aim to establish a protocol for the design of soil bodies from soil data legacy and average information of diagnostic and non-diagnostic soil attributes. It was collected 553 soil samples from 0-0.20 depth along the highways of São Paulo State, within the geological province of the Western Plateau of São Paulo. Data from geology, geomorphology, pedology and landform maps were used. Clay content, magnetic susceptibility, oxalate and dithionite iron, hematite and goethite, kaolinite and gibbsite were assessed for each auxiliary information and for the union of these data. The variability of the attributes was analyzed through their amplitude (maximum and minimum values) and the means were used for the establishment of the protocol. Samples that presented the same geology, dissection, pedology and landform were concatenated, leading to 96 groups. The means of these groups were submitted to cluster analysis to evaluate the data structure and reduce the final number of groups. The groups obtained from cluster analysis were submitted to geostatistical analysis for the creation of isoline maps. The results indicated remarkable difference between the attributes mainly for the geological and pedological data. Cluster analysis revealed the influence of each information on group separation. For the whole area, 11 groups or soil bodies were designed, considering the Euclidian distance of (08) eight. These soil bodies, considered similar by the cluster analysis might help on the determination of the best places to open trenches and consequently for soil data collection. This design of soil bodies, in addition to consider auxiliary information and variability of soil attributes, might help to decrease the subjectivity associated to the traditional soil mapping.