Sistemas de preparo de solo e acúmulo de metais pesados no solo e na cultura do pimentão (Capsicum Annum L.) Systems preparation of soil and accumulation of heavy metals in the soil and in the culture of pepper (Capsicum Annum L.)

Este trabalho teve por objetivos determinar a influência de diferentes métodos de preparo do solo sobre as perdas por erosão de metais pesados e na contaminação do solo e de frutos de pimentão (Capsicum annuum L.) com esses elementos. A avaliação foi realizada durante os meses de dezembro de 1999 a março de 2000, no ciclo de cultivo do Pimentão (Capsicum annuum L.). Foram utilizadas parcelas do tipo Wischmeier, de tamanho de 22,0 x 4,0m. Os tratamentos utilizados foram os seguintes: (i) aração com trator morro abaixo e queima dos resíduos vegetais (MAQ); (ii) aração com trator morro abaixo e não queima dos resíduos vegetais (MANQ); (iii) aração com tração animal em nível, faixas de capim colonião a cada 7,0m (AA) e (iv) cultivo mínimo, com preparo de covas em nível (CM). As perdas mais elevadas de metais pesados por erosão foram verificadas no tratamento MAQ, típico da região. A concentração de Pb no fruto in natura, nos quatros sistemas de preparo do solo, e de Cd no CM estiveram acima dos limites permitidos para alimentos in natura, estando impróprios para o consumo humano Os resultados obtidos neste trabalho permitem concluir que o uso intensivo de agroquímicos associados às elevadas perdas de solo por erosão pode determinar sérios riscos de contaminação do solo, água e alimentos produzidos.<br>The objectives of this study were to determine the influence of different soil tillage methods on the loss of heavy metals by erosion, and to evaluate the level of contamination of soil and food in Paty do Alferes County, State of Rio de Janeiro, Brazil. The experiment was conducted from December of 1999 to March of 2000, and pepper (Capsicum annuum L.) was the cultivated crop. Four Wichmeier plots were installed, with an area of 22 x 4m. The treatments utilized were the following: (i) tillage with machinery and operation down hill and burning of the grassland (MAQ); (ii) tillage with machinery and operation down and without burning of grassland between lines of crop (MANQ); (iii) tillage with animal traction and following the natural contour of the hill, strip cropping grass each 7m (AA); and minimum tillage, (CM). The highest losses of heavy metals by erosion were in the MAQ treatment. The minimum tillage showed greater accumulation of heavy metals than others soil tillage methods, due to lower erosion losses in this trial. The concentration of Pb in fruits in natura, in the four soil tillage methods, was above the levels allowed to food consumption. The results obtained in this work allow to conclude that the intensive use of agrochemistrys associated the high soil losses by erosion can determine serious risks of contamination of soil, water and foods

Assessment of heavy metals in soils of a vineyard region with the use of principal component analysis Avaliação de metais pesados em solos de região de vinhedos com o uso da análise dos componentes principais

Agricultural management with chemicals may contaminate the soil with heavy metals. The objective of this study was to apply Principal Component Analysis and geoprocessing techniques to identify the origin of the metals Cu, Fe, Mn, Zn, Ni, Pb, Cr and Cd as potential contaminants of agricultural soils. The study was developed in an area of vineyard cultivation in the State of São Paulo, Brazil. Soil samples were collected and GPS located under different uses and coverings. The metal concentrations in the soils were determined using the DTPA method. The Cu and Zn content was considered high in most of the samples, and was larger in the areas cultivated with vineyards that had been under the application of fungicides for several decades. The concentrations of Cu and Zn were correlated. The geoprocessing techniques and the Principal Component Analysis confirmed the enrichment of the soil with Cu and Zn because of the use and management of the vineyards with chemicals in the preceding decades.<br>O manejo agrícola com agroquímicos pode levar a contaminação dos solos por metais pesados. O objetivo deste trabalho foi aplicar a Análise dos Componentes Principais e técnicas de geoprocessamento para identificar a origem dos metais pesados Cu, Fe, Mn, Zn, Ni, Pb, Cr e Cd como contaminantes potenciais em solos agrícolas. O estudo foi desenvolvido em uma área cultivada com vinhedos no Estado de São Paulo, Brazil. Amostras de solos foram coletadas e georeferenciadas por GPS sob diferentes usos e coberturas. As concentrações dos metais nos solos foram obtidas pelo método de extração com DTPA. As concentrações de Cu e Zn foram consideradas altas na maioria das amostras pesquisadas, sendo maiores nas áreas cultivadas com vinhedos sob aplicações de fungicidas por décadas. As concentrações de Cu e Zn apresentaram correlação. As técnicas de geoprocessamento e a Análise dos Componentes Principais indicaram enriquecimento do solo com Cu e Zn devido ao uso e manejo dos vinhedos com agroquímicos nas décadas anteriores

HEAVY METALS IN VINEYARDS AND ORCHARD SOILS

The application of foliar fungicides in vineyards and orchards can increase soil concentration of heavy metals such as copper (Cu) and zinc (Zn), up to the toxicity threshold for fruit trees and cover crops. However, some agronomic practices, such as liming, addition of organic fertilizers, cultivation of soil cover crops and inoculation of young plants with arbuscular mycorrhizal fungi can decrease the availability and the potential of heavy metal toxicity to fruit trees. This review aims to compile and present information about the effects of increasing concentrations of heavy metals, especially Cu and Zn, on soils cultivated with fruit trees and provides some agronomic practices of remediation. Information about the sources of heavy metals found in soils cultivated with fruit trees are presented; mechanisms of absorption, transport, accumulation and potential toxicity to plants are described