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717 results on '"Curi, Nilton"'

163. Soils of the Brazilian Coastal Plains biome: prediction of chemical attributes via portable X-ray fluorescence (pXRF) spectrometry and robust prediction models

Author

Faria, Álvaro José Gomes de, primary, Silva, Sérgio Henrique Godinho, additional, Melo, Leônidas Carrijo Azevedo, additional, Andrade, Renata, additional, Mancini, Marcelo, additional, Mesquita, Luiz Felipe, additional, Teixeira, Anita Fernanda dos Santos, additional, Guilherme, Luiz Roberto Guimarães, additional, and Curi, Nilton, additional

Published
2020
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168. Sustainable productive intensification for family farming in developing tropical countries

Author

Taveira, Luís Renato Silva, Carvalho, Teotonio Soares de, Teixeira, Anita Fernanda dos Santos, and Curi, Nilton

Subjects
Farming system, Sistemas agrícolas, agricultor familiar, family farmer, capitalismo, capitalism, food production, sustainability, sustentabilidade, produção de alimentos
Abstract

In the past, agriculture was directed to satisfying human needs. Nowadays, it is directed to meeting the markets, forcing the peasantries to adapt to this condition. As a result, family farmers are multifaceted, incorporating both subsistence and market-oriented production. Traditional farming systems have been challenged since there is a pressure for the intensification of these systems. Then, it is important that scientific research about them goes on to recognize that many family farmers use limited resource bases. However, innovation and intensification are permanent needs of agriculture, although they must be adjusted to different contexts, respecting the cultural legacy of family farmers as a prerequisite for achieving the development. RESUMO No passado, a agricultura era direcionada para satisfazer as necessidades humanas. Hoje em dia, é direcionada para atender os mercados, forçando o campesinato a se adaptar a essa condição. Como resultado, os agricultores familiares se tornaram multifacetados, incorporando tanto a produção de subsistência quanto aquela orientada para o mercado. Os sistemas agrícolas tradicionais foram desafiados, uma vez que existe uma pressão para a intensificação desses sistemas. Então, é importante que a pesquisa científica sobre eles continue para reconhecer que muitos agricultores familiares usam bases de recursos limitadas. Contudo, inovação e intensificação são necessidades permanentes da agricultura, embora elas devam ser ajustadas a diferentes contextos, respeitando o legado cultural dos agricultores familiares como pré-requisito para alcançar o desenvolvimento.

Published
2019

171. Adsorption and availability of phosphorus in response to humic acid rates in soils limed with CaCO3 or MgCO3

Author

Maluf, Henrique José Guimarães Moreira, Silva, Carlos Alberto, Curi, Nilton, Norton, Lloyd Darrell, and Rosa, Sara Dantas

Subjects
Organic ligands, Ligantes orgânicos, calagem, fator capacidade de P máximo, phosphate maximum buffering capacity, isoterma de Langmuir, liming, humic acid-metal-P complexes, Langmuir isotherm, complexos ácido húmico-metal-P
Abstract

Humic acid (HA) may reduce adsorption and increase soil P availability, however, the magnitude of this effect is different when Ca2+ prevails over Mg2+ in limed soils. The objective of this study was to evaluate the effects of HA rates and carbonate sources on the adsorption, phosphate maximum buffering capacity (PMBC), and P availability in two contrasting soils. Oxisol and Entisol samples were firstly incubated with the following HA rates: 0, 20, 50, 100, 200 and 400 mg kg-1, combined with CaCO3 or MgCO3, to evaluate P adsorption. In sequence, soil samples were newly incubated with P (400 mg kg-1) to evaluate P availability. The least P adsorption was found when 296 mg kg-1 of HA was added to Oxisol. Applying HA rates decreased maximum adsorption capacity, increased P binding energy to soil colloids and did not alter PMBC of Entisol. Available P contents in Oxisol increased with HA rates, but it did not change in Entisol. Choosing the right HA rate can decrease PMBC up to 40% and increase the Oxisol P availability by 17%. Application of MgCO3 instead of CaCO3 decreased P adsorption in both soils. Thus, a positive correlation between Ca2+ content and PMBC was verified. Optimum rate of HA and the preponderance of Mg2+ instead of Ca2+ in soil volume fertilized with P are effective practices to reduce adsorption and increase P availability, especially in clayey Oxisol. RESUMO O ácido húmico (AH) pode reduzir a adsorção e aumentar a disponibilidade de P nos solos, entretanto, a magnitude desse efeito é diferente quando o Ca2+ prevalece sobre Mg2+ em solos com acidez corrigida. Objetivou-se avaliar os efeitos de doses de AH e fontes de carbonato na adsorção, fator capacidade de P máximo (FCPm) e disponibilidade de P em solos contrastantes. Amostras de Latossolo e Gleissolo foram primeiramente incubadas com as seguintes doses de AH: 0, 20, 50, 100, 200 e 400 mg kg-1, combinadas com CaCO3 ou MgCO3, para avaliar a adsorção de P. Em sequência, as amostras de solo foram novamente incubadas com P (400 mg kg-1), para determinar a disponibilidade de P. A aplicação de doses de AH reduziu a capacidade máxima de adsorção, aumentou a energia de ligação do P e não alterou a FCPm do Gleissolo. O teor de P disponível aumentou com o acréscimo das doses de AH no Latossolo, contudo, não foram alterados no Gleissolo. A escolha correta da dose de AH reduziu a FCPm em até 40% e aumentou a disponibilidade de P no Latossolo em 17%. A aplicação de MgCO3 em vez do CaCO3 reduziu a adsorção de P em ambos os solos. Assim, houve correlação positiva entre o teor de Ca2+ e a FCPm. A dose ótima de AH e a predominância de Mg2+ sobre Ca2+ no volume de solo adubado com P são práticas efetivas para reduzir a adsorção e aumentar a disponibilidade de P, especialmente, no Latossolo argiloso.

Published
2018

188. Land use capability classification adaptation in low and intermediate technology farming systems: A soil erosion indicator.

Author

Taveira, Luís R. S., Weindorf, David C., De Menezes, Michele D., de Carvalho, Teotonio Soares, Da Motta, Paulo Emílio F., Teixeira, Anita Fernanda dos Santos, Curi, Nilton, and Aitkenhead, Matt

Subjects
ZONING, APPROPRIATE technology, SOIL erosion, LAND management, LAND use mapping, AGROFORESTRY
Abstract

Land classification assists in identifying optimal crop selection for a given field, and land use capability gives an indication of potential agronomic productivity. However, these approaches are most germane to farming systems managed with high technology. This study sought to adapt land use capability to farming systems managed with low and intermediate levels of technology. Assessment of the classification criteria was conducted using erosion data as a primary indicator. The adapted (and currently in effect) criteria were compared in three regions in Minas Gerais, Brazil, each one representing one of the management levels. Erosion often results from inappropriate practices in land use or management. Therefore, maps of adequacy of land use and management were used to measure how well each one corresponded to the erosion map. The adapted criteria changed the spatial distribution of the classes of land use capability in different ways. Correspondence between the land use/management map and the erosion map increased from 71% to 88.5% when the criteria adapted to an intermediate level of management were used. It also increased from 62.9% to 66.7% when the criteria adapted to a low level of management were considered, better reflecting current erosion. Therefore, adopting adapted classification criteria is recommended for planning land use in locations where farming systems with low and intermediate levels of management are common, requiring re‐adaptation and reassessment depending on socio‐environmental factors. [ABSTRACT FROM AUTHOR]

Published
2021
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189. Silicon-phosphorus interactions in soils cultivated with bean plants - doi: 10.4025/actasciagron.v36i1.17240

Author

Alovisi, Alessandra Mayumi Tokura, Furtini Neto, Antonio Eduardo, Carneiro, Leandro Flávio, Curi, Nilton, and Alovisi, Alves Alexandre

Subjects
dry matter of the aerial part, productivity, Phaseolus vulgaris L, Fertilidade do solo e Adubação, lcsh:Agriculture (General), lcsh:S1-972, phosphated fertilization, silicon fertilization
Abstract

Aiming to evaluate the effects of doses silicon and phosphorus on the phosphate nutrition and production in bean plants, two experiments were conducted in a greenhouse using two soils, Orthic Quartzarenic Neosol (RQo) and Dystroferric Red Latosol (LVdf). Each soil was subjected to three incubation sequences: the first with lime to raise the base saturation to 50%, the second with silicic acid, Si with three doses (0, 240 and 410 and 0, 330 and 560 mg dm-3, respectively, for RQo and LVdf) and the third with basic fertilisation, including phosphorus at four different doses (0, 80, 240 and 410 and 0, 110, 330 and 560 mg dm-3 for RQo and LVdf, respectively). The experiment was performed using a completely randomised 3 x 4 factorial, with four replications. The application of Si did not influence the dry matter production of the aerial part (APDM) or the grain dry matter (DGM) and P accumulation in the aerial part of the bean plants, yet the higher doses of Si increased the accumulation of Si in the APDM. The application of P increased the yield of the APDM and DGM and phosphorus accumulation in the APDM of the bean plants.

Published
2014

190. Assessing soil contamination in automobile scrap yards by portable X-ray fluorescence spectrometry and magnetic susceptibility.

Author

Barbosa, Julierme Zimmer, Poggere, Giovana Clarice, Teixeira, Wilson Wagner Ribeiro, Motta, Antonio Carlos Vargas, Prior, Stephen A., and Curi, Nilton

Subjects
SOIL pollution, X-ray fluorescence, FLUORESCENCE spectroscopy, MAGNETIC susceptibility, AUTOMOBILE parts, TOPSOIL
Abstract

A by-product of industrialization and population growth, automobile scrap yards are a potential source of metal contamination in soil. This study evaluated the use of portable X-ray fluorescence (pXRF) spectrometry and magnetic susceptibility (χ) analysis in assessing metal soil contamination in scrap yards located in Brazil. Five automobile scrap yards were selected in Curitiba, Paraná State (CB1, CB2, and CB3) and Lavras, Minas Gerais State (LV1 and LV2). By evaluating metal concentrations and geoaccumulation index values, we verified moderate Cu, Pb, and Zr contamination and moderate to high Zn contamination, primarily in the topsoil (0–10 cm). Soil Zn concentrations in automobile scrap yards were on average four times higher than in reference soils, suggesting that galvanized automobile parts may be the primary source of this soil contaminant. Although other elements (i.e., As, Cr, Fe, Nb, Ni, and Y) were slightly increased compared to reference values in one or more soils, concentrations did not constitute contamination. Automobile scrap yard topsoil had higher χ values (5.8 to 52.9 × 10−7 m3 kg−1) at low frequency (χlf) compared to reference soil (3.6 to 7.5 × 10−7 m3 kg−1). The highest values of χlf occurred in LV soils, which also represented the highest Zn contamination. Magnetic multidomain characteristics (percent frequency–dependent susceptibility between 2 and 10) indicated magnetic particle contributions of anthropogenic origin. The use of pXRF and χlf as non-destructive techniques displays potential for identifying soil contamination in automobile scrap yards. [ABSTRACT FROM AUTHOR]

Published
2020
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