Cruz das Almas, Brazil
Cruz das Almas, Brazil

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dos Santos N.M.,Federal Rural University of Pernambuco | Accioly A.M.A.,Rua Embrapa | do Nascimento C.W.A.,Federal Rural University of Pernambuco | Santos J.A.G.,Federal University of Recôncavo da Bahia | Silva I.R.,Federal University of Viçosa
Revista Brasileira de Ciencia do Solo | Year: 2014

Soil contamination by Pb poses a significant risk to human health. The municipality of Santo Amaro da Purificação, Bahia, Brazil, has one of the most severe cases of contamination of this metal in the world. The objective of this study was to evaluate the effect of humic acids and activated charcoal as soil amendments for reducing the toxicity of Pb to corn plants grown in contaminated soil collected near the area of the company responsible for the contamination. Application rates were based on the C content of the materials (humic acid from composting - AHv, commercial humic acid - AHc, and charcoal - CV) and corresponded to 0, 0.75, 1.5, 3 and 7.5 g kg-1 of C in the soil. At 43 days of growth, the plants were cut at ground level, separated into shoots and roots, and Pb contents were determined by nitro-perchloric digestion. The concentrations of chlorophyll a and b were also evaluated to evaluate the effect of the metal on the photosynthetic apparatus. The soil amendments applied to contaminated soil were effective in reducing the stress of Pb in corn plants. The highest efficiency was obtained from AHv, followed by CV and AHc. All the soil amendments tested decreased translocation of Pb to the shoots. This implies a greater fixation of the metal in the soil and, consequently, a reduction in the risk of transfer to the food chain. For this reason, these materials can be recommended as soil amendments for Pb phytostabilization in soils.


do Sacramento J.A.A.S.,Federal University of Recôncavo da Bahia | Araujo A.C.M.,Federal University of Ceará | Escobar M.E.O.,Federal University of Ceará | Xavier F.A.S.,Rua Embrapa | And 2 more authors.
Revista Brasileira de Ciencia do Solo | Year: 2013

In the semiarid region of Brazil, inadequate management of cropping systems and low plant biomass production can contribute to reduce soil carbon (C) and nitrogen (N) stocks; therefore, management systems that preserve C and N must be adopted. This study aimed to evaluate the changes in soil C and N stocks that were promoted by agroforestry (agrosilvopastoral and silvopastoral) and traditional agricultural systems (slash-and-burn clearing and cultivation for two and three years) and to compare these systems with the natural Caatinga vegetation after 13 years of cultivation. The experiment was carried out on a typical Ortic Chromic Luvisol in the municipality of Sobral, Ceará, Brazil. Soil samples were collected (layers 0-6, 6-12, 12-20, 20-40 and 40-60 cm) with four replications. The plain, convex and concave landforms in each study situation were analyzed, and the total organic C, total N and densities of the soil samples were assessed. The silvopastoral system promoted the greatest long-term reductions in C and N stocks, while the agrosilvopastoral system promoted the smallest losses and therefore represents a sustainable alternative for soil C and N sequestration in these semiarid conditions. The traditional agricultural system produced reductions of 58.87 and 9.57 Mg ha-1 in the organic C and total N stocks, respectively, which suggests that this system is inadequate for these semiarid conditions. The organic C stocks were largest in the concave landform in the agrosilvopastoral system and in the plain landform in the silvopastoral system, while the total N values were highest in the concave landform in the native, agrosilvopastoral and silvopastoral systems.


Oliveira A.M.G.,Rua Embrapa | Natale W.,Laval University | Rosa R.C.C.,Rua Embrapa | Junghans D.T.,Rua Embrapa
Revista Brasileira de Fruticultura | Year: 2015

The ‘BRS Imperial’ pineapple is a resistant cultivar to Fusarium and it presents tasty fruit, but it is still little known by farmers. This study aimed to evaluate the influence of N and K fertilization on chemical soil characteristics, leaves nutrient contents and yield of ‘BRS Imperial’ plants. The experiment was installed at a 0.90 × 0.40 × 0.40 m spacing and four doses of N (0, 160, 320, 550 kg ha-1) and K2O (0, 240, 480 and 600 kg ha-1) were tested in a completely randomized blocks design with five replicates, in a 4 × 4 complete factorial scheme. Chemical analyzes were made of leaves and soil and measured the production variables. The cultivation of pineapple in a complete absence of N and K fertilization resulted in lower pH, K+, Ca2+ and Mg2+ levels of soil in relation to the initial content. Even at the highest dose of K2O, the K level in the soil was low after the pineapple cultivation. The maximum N and K foliar content, estimated on the higher doses, were 13 g kg-1 and 32 g kg-1, respectively. Crop variables showed significance for N levels in all evaluations, while the rates of K2O influenced only the length/diameter fruit relation. In a quadratic regression, N doses showed 1,086 g on fruit weight with crown at 365 kg ha-1 of N and a yield of 42 t ha-1. © 2015, Sociedade Brasileira de Fruticultura. All rights reserved.


Oliveira A.M.G.,Rua Embrapa | Natale W.,Laval University | Rosa R.C.C.,Rua Embrapa | Junghans D.T.,Rua Embrapa
Revista Brasileira de Fruticultura | Year: 2015

The ‘BRS Imperial’ pineapple is a resistant cultivar to Fusarium, with leaves without thorns, but it requires a specific technical information for its management. This study aimed to evaluate the effect of different levels of N and K2O on vegetative growth, flowering and in the attributes of ‘D’ leaf development of ‘BRS Imperial’ pineapple, in order to determinate the plant parameters to induce artificial flowering. In a complete randomized block design with five replications, we tested four N (0, 160, 320, 550 kg ha-1) and four K2O (0, 240, 480 and 600 kg ha-1) levels, in a complete factorial 4 × 4. Potassium fertilization positively influenced in fresh mass and plant length, as well as the number of slip per plant; while the nitrogen fertilization influenced the leaf emergence and fresh mass of slip. Nitrogen fertilization decreased the artificially induced flowering, while potassium increased the flowering rate. The maximum mass of the ‘D’ leaf was estimated at 56 g, in the dose of 364 kg N ha-1 and higher dose of potassium fertilizer (600 kg ha-1 K2O). The mass of ‘D’ leaf showed the best correlation with fruit mass and estimated the minimum mass of 44 g to obtain 900 g of fruit, the minimum mass required by the market for sale. © 2015, Sociedade Brasileira de Fruticultura. All rights reserved.

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