Protocol for the use of legacy data and magnetic signature on soil mapping of São Paulo Central West, Brazil.

The demand for information on the soil resource to support the establishment of public policies for land use and management has grown exponentially in the last years. However, there are still difficulties to the proper use of already existing information for soil mapping. Here we aimed to establish a protocol for soil mapping using legacy data, magnetic signature and soil attributes evaluation. A total of 493 soil samples were collected at 0-0.20 m in the geological domain of Western Plateau of São Paulo State. This work has three parts: First, we performed a classification analysis using soil mapping units (SMU) extracted from conventional soil map and Support Vector Machines algorithm (SVM). As covariates, we used categorical information, such as geology, dissection and landform maps. Second, we used soil attributes to perform a cluster analysis using k-means as partitioning method. To choose the optimal number of clusters, the same number of SMU showed in the conventional soil map (e.g. 34 clusters) were used. The last step was to compare soil and clusters maps predicted by SVM with the conventional soil map. Results showed good performance of SVM for both classifications (clusters and SMU), with overall accuracy of 0.60 and 0.90 respectively. In addition, the distribution of soil attributes within each cluster was more homogeneous and well distributed than within SMU, showing that is very possible to use numerical classification for soil mapping. Future soil surveys could use cluster analysis as a preliminary evaluation for better understanding of tropical soil variations.

Cadmium background concentrations to establish reference quality values for soils of São Paulo State, Brazil.

Proper assessment of soil cadmium (Cd) concentrations is essential to establish legislative limits. The present study aimed to assess background Cd concentrations in soils from the state of São Paulo, Brazil, and to correlate such concentrations with several soil attributes. The topsoil samples (n = 191) were assessed for total Cd contents and for other metals using the USEPA 3051A method. The background concentration was determined according to the third quartile (75th). Principal component analysis, Spearman correlation, and multiple regressions between Cd contents and other soil attributes (pH, cation exchange capacity (CEC), clay content, sum of bases, organic matter, and total Fe, Al, Zn, and Pb levels) were performed. The mean Cd concentration of all 191 samples was 0.4 mg kg(-1), and the background concentration was 0.5 mg kg(-1). After the samples were grouped by parent material (rock origin) and soil type, the background Cd content varied, i.e., soils from igneous, metamorphic, and sedimentary rocks harbored 1.5, 0.4, and 0.2 mg kg(-1) of Cd, respectively. The background Cd content in Oxisols (0.8 mg kg(-1)) was higher than in Ultisols (0.3 mg kg(-1)). Multiple regression demonstrated that Fe was primarily attributed to the natural Cd contents in the soils (R (2) = 0.79). Instead of a single Cd background concentration value representing all São Paulo soils, we propose that the concentrations should be specific for at least Oxisols and Ultisols, which are the primary soil types.

Floristic and phytosociology in a physiognomic gradient of riverine forest in Cerrado, Campinas, SP / Floristica e fitossociologia em um gradiente fisionomico de floresta ribeirinha em Cerrado, Campinas, SP

Knowledge on floristic composition and vegetation structure is essential to preserve plant biodiversity and environmental conditions. A floristic and structural survey of woody vegetation was carried out in a physiognomic gradient of riparian forest of Cerrado vegetation, Campinas - SP. We sampled 25 plots, distributed along five transects, located perpendicularly to a stream. We found 971 individuals (65 standing dead trees) distributed among 35 families and 80 species. We recorded one single individual of exotic species (Citrus limon – rangpur) and a large number of individuals of endangered species (Luetzelburgia guaissara, Myroxylon peruiferum and Trichilia hirta) indicating that the Santa Elisa study area retains much of the original characteristics of its native vegetation. The small number of exclusive Cerrado species in the study area indicates that riverine environments represent a very different condition in relation to that of the Cerrado. Except for swampy areas, which are more homogeneous and floristically similar to each other due to adaptations to greater environmental constraints, the riverine forest physiognomies showed greater internal floristic heterogeneity, even considering only those located in Cerrado areas. This emphasizes the importance of studying riverine forests flora for each particular region, especially when restoration or management actions are needed. At the Santa Elisa riverine-cerrado transition fragment, riparian species were found throughout gradient up to the limit of the study area showing that a distance of at least 50 m far from the stream should be preserved in order to keep the riparian environment.

Conhecer a composição florística e a estrutura da vegetação é imprescindível quando se trata da conservação da biodiversidade e das condições ambientais. Foi realizado um levantamento florístico e estrutural da vegetação arbórea em um gradiente fisionômico de mata ribeirinha em área de Cerrado, Campinas - SP, em 25 parcelas, distribuídas em cinco transectos, localizados perpendicularmente a um córrego. Foram encontrados 971 indivíduos (65 mortos em pé), pertencentes a 35 famílias e 80 espécies, sendo um único indivíduo de espécie exótica (Citrus limon – limão-vinagre) e um número muito maior de indivíduos de espécies ameaçadas (Luetzelburgia guaissara, Myroxylon peruiferum e Trichilia hirta) indicando que a área de estudo na Fazenda Santa Elisa mantém muito das características originais de sua vegetação nativa. O pequeno número de espécies exclusivas do Cerrado na área de estudo indica que ambientes ribeirinhos representam uma condição muito diferente em relação àquelas do Cerrado. Com exceção de áreas paludícolas, que são mais homogêneas e floristicamente semelhantes devido à adaptação a maiores restrições ambientais, as fisionomias florestais ribeirinhas comparadas mostraram grande heterogeneidade florística, mesmo considerando-se apenas aquelas localizadas em áreas de Cerrado. Isso enfatiza a importância de se estudar a flora das florestas ribeirinhas de cada região em particular, especialmente quando as ações de restauração ou de gestão são necessárias. No fragmento de transição floresta ribeirinha-cerrado da Fazenda Santa Elisa, as espécies exclusivas de florestas ribeirinhas, embora com diferentes densidades, foram encontradas em todo o gradiente até o limite da área de estudo, mostrando que a vegetação deve ser preservada até uma distância de pelo menos 50 m a partir do rio, a fim de manter o ambiente ribeirinho.

The genetic structure and mating system of Acrocomia aculeata (Arecaceae).

Acrocomia aculeata is a perennial, fruit-producing palm tree, native to tropical forests. Its fruits have spurred interest because of their significant potential for use in the cosmetic industry and as feedstock for biofuel. In the present study, the genetic structure and mating system in Acrocomia aculeata were analyzed, using eight nuclear micro-satellite loci and samples from São Paulo and Minas Gerais states, Brazil. By means of Bayesian analysis, these populations were clustered into two or three groups. A high multilocus outcrossing rate suggests that outcrosses were predominant, although a certain degree of biparental inbreeding also occurred. Thus, although monoecious and self-compatible, there is every indication that A. aculeata bears a mixed reproductive system, with a predominance of outcrossing. Given the genetic structure revealed hereby, future conservation strategies and germplasm collecting should be focussed on sampling and preserving individuals from different clusters.

The genetic structure and mating system of Acrocomia aculeata (Arecaceae)

Acrocomia aculeata is a perennial, fruit-producing palm tree, native to tropical forests. Its fruits have spurred interest because of their significant potential for use in the cosmetic industry and as feedstock for biofuel. In the present study, the genetic structure and mating system in Acrocomia aculeata were analyzed, using eight nuclear microsatellite loci and samples from São Paulo and Minas Gerais states, Brazil. By means of Bayesian analysis, these populations were clustered into two or three groups. A high multilocus outcrossing rate suggests that outcrosses were predominant, although a certain degree of biparental inbreeding also occurred. Thus, although monoecious and self-compatible, there is every indication that A. aculeata bears a mixed reproductive system, with a predominance of outcrossing. Given the genetic structure revealed hereby, future conservation strategies and germplasm collecting should be focussed on sampling and preserving individuals from different clusters.

Classification of Brazilian soils by using LIBS and variable selection in the wavelet domain.

This paper proposes a novel analytical methodology for soil classification based on the use of laser-induced breakdown spectroscopy (LIBS) and chemometric techniques. In the proposed methodology, linear discriminant analysis (LDA) is employed to build a classification model on the basis of a reduced subset of spectral variables. For the purpose of variable selection, three techniques are considered, namely the successive projection algorithm (SPA), the genetic algorithm (GA), and a stepwise formulation (SW). The use of a data compression procedure in the wavelet domain is also proposed to reduce the computational workload involved in the variable selection process. The methodology is validated in a case study involving the classification of 149 Brazilian soil samples into three different orders (Argissolo, Latossolo and Nitossolo). For means of comparison, soft independent modelling of class analogy (SIMCA) models are also employed. The best discrimination of soil types was attained by SPA-LDA, which achieved an average classification rate of 90% in the validation set and 72% in cross-validation. Moreover, the proposed wavelet compression procedure was found to be of value by providing a 100-fold reduction in computational workload without significantly compromising the classification accuracy of the resulting models.