Navegando por Autor "Silva, Davi J."
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Artigo Changes in soil fertility and mineral nutrition of mango orchards in São Francisco Valley, Brazil(UFRPE, 2014-03) Cunha, Karina Patrícia Vieira da; Silva, João P. S. da; Nascimento, Clístenes W. A. do; Silva, Davi J.; Biondi, Caroline M.This research aimed to analyse the soil fertility changes and macronutrient concentration in mango plantations in Petrolina, Pernambuco, Brazil. Samples of soil were collected at depths of 0-20 and 20-40 cm, and leaves of mango trees during vegetative growth were collected from 11 areas with different cultivation time spans (6, 7, 8, 9, 10, 11, 14, 16, 17, 19, and 26 years). Nearby areas under natural vegetation were sampled for reference. The chemical characteristics of soil evaluated were: pH; P, K, Ca, Mg; exchangeable Na and Al; H + Al; organic matter; sum of bases; base saturation; and total cation exchange capacity. The mango leaves were analysed for N, P, K, Ca, and Mg. The agricultural management practices adopted by the mango-producing companies promoted changes in soil fertility when compared with the reference areas. The concentrations of organic matter tended to increase in the crop areas. The organic matter caused increases in CEC and nutrient retention. High P values were observed in soils and plants owing to the excessive use of fertilizers. This may cause nutritional imbalance and contamination of water sources. The contents of N, P, K in the leaves of mango trees were nutritionally adequateArtigo Soil contamination by heavy metals in vineyard of a semiarid region: an approach using multivariate analysis(Elsevier BV, 2016-11-22) Cunha, Karina Patrícia Vieira da; Preston, Welka; Silva, Yuri J. A. B. da; Nascimento, Clístenes W. A.; Silva, Davi J.; Ferreira, Hailson A.Contamination of vineyard soils by the continuous use of cupric fungicides and fertilizers has been a worldwide concern. The objective of this study was to determine the total concentration of Cu, Zn, Fe, Mn, Ni and Pb from vineyard soils of a semiarid region in Brazil. Soil samples at 0–20 and 20–40 cm depth were collected in areas under 5, 6, 8, 10, 12, 15, 16 and 30 years of cultivation, and compared with native vegetation areas. Samples were digested and total metal concentrations were determined by atomic absorption spectrophotometer. In general, concentrations of Mn, Ni, Fe and Pb were similar to those values found in the reference area, being regarded as background concentrations. On the other hand, Zn and Cu were mainly derived from the widespread use of fertilizers (e.g., phosphate application) and cupric fungicides, respectively. Discriminant analysis clearly demonstrated higher metal accumulation in surface soil samples, chiefly Zn and Cu owing to Zn and Cu-containing chemicals and accumulation of organic matter. This tool was also useful to differentiate between natural and anthropogenic inputs of metals into soils. The high enrichment factor values for Cu and Zn showed that both were mainly derived from anthropogenic sources