ABSTRACT:The purpose of this study was to evaluate Cu and Zn migration and fractions in sandy soil of vineyards. In Urussanga (SC), Brazil, soil samples were collected from a 4-year-old and 15-yearold vineyard, and from a forested area. In the soils, the chemical characteristics of Cu and Zn were analyzed by the EDTA method, which determines the fraction available in soil; 3050B method of the USEPA for total concentrations, which represents the pseudo-

The reforestation with eucalyptus has increased significantly in the Brazilian Savanah and it can promote changes on soil biological properties, mainly soil fauna. Thus, the aim of this study was to evaluate the composition of soil fauna in areas with Eucalyptus plantations of different ages compared with native savanna. The study was conducted in Eucalytptus plantations aged one, two, three and four years and area with native forest was taken as reference. Soil fauna was collected in the dry and rainy season to evaluate the number of individuals from different taxonomic groups, richness, uniformity and diversity. The highest number of soil fauna was found in eucalyptus plantations with one year old at both seasons. However, the richness did not differ between seasons. In areas where with eucalyptus plantations with one and two years old showed 90% of individuals represented by Coleoptera and Formicidae, which contributed for decreasing in fauna uniformity. The implantation of Eucalyptus early reduced the diversity and uniformity of soil fauna; however, there was a recovery of this biological attribute after two years of reforestation.Additional keywords: native forest; seasonality; species diversity. ResumoO plantio de eucalipto tem aumentado significativamente em áreas anteriormente ocupadas por vegetação de Cerrados, e isto pode promover mudanças nos atributos biológicos do solo, principalmente sobre a fauna edáfica. Desta forma, o objetivo do trabalho foi avaliar a composição da fauna do solo em povoamentos de eucalipto do solo com diferentes idades, em comparação com remanescentes de vegetação de Cerrados. O estudo foi realizado em quatro povoamentos de eucalipto, com 1; 2; 3 e 4 anos, e uma mata nativa de Cerrado como referência. Foram feitas avaliações do número de indivíduos de grupos taxonômicos da fauna do solo, e de características ecológicas dos grupos dessa fauna, como riqueza, riqueza média, índice de diversidade e de uniformidade. As coletas da fauna do solo foram realizadas nas estações úmida e seca. O maior número de indivíduos da fauna edáfica foi encontrado no povoamento de indivíduos com 1 ano de idade. A riqueza de espécies não diferiu entre as estações de coleta nas áreas avaliadas. Nos povoamentos com 1 e 2 anos de idade, aproximadamente 90% do total de indivíduos foram representados por Coleoptera e Formicidae, o que contribuiu para diminuir a uniformidade. Eucaliptos com menor tempo de implantação mostraram menor diversidade e uniformidade da fauna edáfica, entretanto houve recuperação destes atributos após dois anos de implantação.Palavras-chave adicionais: diversidade de espécie; mata nativa; sazonalidade.

BACKGROUND The natural abundance of stable isotope 15N (δ15N) in production systems has emerged as an alternative to distinguish organic products from conventional ones. This study evaluated the use of δ15N values recorded for nitrogen fertilizers, soil and plant tissue in order to set the differences between organic and conventional agricultural production systems applied to rice, potatoes, apple and banana crops. RESULTS Values of δ15N recorded for N sources ranged from +5.58‰ to +18.27‰ and from −3.55‰ to +3.19‰ in organic and synthetic fertilizers, respectively. Values recorded for δ15N in food from organic rice, potatoes and banana farms were higher than values recorded for δ15N in conventional farms; the same was observed for values recorded for δ15N in leaves from the four crops. CONCLUSION Results have allowed for differentiation between production systems due to values of δ15N recorded in leaves of all crops and food, for rice, potatoes and banana trees. © 2021 Society of Chemical Industry.

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Establishing Cu and Zn transport limits to soil solution, may be a parameter to regulate maximum allowable concentrations of these heavy metals in soils. The study aimed to estimate Cu and Zn contents in soil mixtures with varying clay and soil organic matter (SOM) contents, from which the two heavy metals are transported to the soil solution. Samples of the Bw horizon of a Oxisol and of the A horizon of a Inceptisol were used to make soil mixtures with clay contents ranging from 170 to 700 g kg− 1 and SOM ranging from 18 to 95 g kg− 1. Cu and Zn adsorption curves were obtained to determine the maximum adsorption capacities (MAC) using the Langmuir model. Cu transport limits ranged from 118 to 187 mg kg− 1 the lowest values were found in soil mixtures containing lower clay contents in combination with higher SOM contents. Zn transport limits ranged from 61 to 116 mg kg− 1 the highest values were found in soil mixtures containing lower clay contents combined with higher SOM contents. Cu and Zn transport limits can be used as safe limits for supervisory bodies, technical assistance institutions and farmers to monitor the potential for environmental contamination.