RESUMO
BACKGROUND: The combination of near-infrared (NIR) spectroscopy and chemometrics can be used to group or discriminate soils based on spectral response. In this study, we conducted discrimination and classification analyses on soils managed with different sources of fertilization and plant species grown in organic and conventional farming systems. RESULTS: Principal component analysis explained 96% (PC1) and 3% (PC2) of the data variability and separated the soil samples of organic and conventional management systems. The wavenumbers that contributed most to the separation of the management systems were in the range of 3600 and 7300 cm-1 , especially the absorption peaks of 3700 and 4600 cm-1 (characteristic of CH and NH combinations), and 5200 and 7000 cm-1 (typical of OH combinations). Machine learning analysis using k-nearest neighbor and random forest algorithms was efficient in classifying soil samples according to management system with an accuracy of 97.8% and can therefore be used for future classification studies. CONCLUSION: Based on the results, we strongly recommend the use of NIR spectroscopy associated with chemometrics for discriminating soils grown with Malus domestica, Musa spp., Oryza sativa and Solanum tuberosum L. under organic and conventional management systems through spectral response. © 2021 Society of Chemical Industry.
Assuntos
Fertilizantes/análise , Solo/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Agricultura , Algoritmos , Produtos Agrícolas/crescimento & desenvolvimento , Análise Discriminante , Análise de Componente PrincipalRESUMO
Soil contamination with copper (Cu)-based agrochemicals used in vineyards for pest control is a growing problem. In this context, the application of soil amendment to limit Cu toxicity, especially for young plants after the replanting of vineyards, has been a concern for winemakers. Therefore, the aim of this study was to evaluate how different amendments can contribute to the decrease in Cu availability in areas vocated to viticulture. Furthermore, the aim was to evaluate to the effect of Cu on the biochemical and physiological changes in the development of the young vine plants, both at the shoot and the root level. Vine plants were grown in a greenhouse using a Typic Hapludalf soil characterized by 87.5â¯mg of Cu kg-1 (control). Three different amendments were applied to the soil: limestone (3â¯Mgâ¯ha-1), calcium silicate (3â¯Mgâ¯ha-1) and vermicompost (30â¯g of C kg-1). The amendment with vermicompost and calcium silicate caused a significant alkalization of the soil solution. Moreover, specifically for the treatment with vermicompost, the levels of Cu2+ in the soil solution were consistently diminished with a clear benefit for plants (+89% biomass accumulation at the shoot level). In addition, this soil amendment led to a higher photosynthetic rate, lower superoxide dismutase (SOD, EC 1.15.1.1) and guaiacol peroxidase (POD, EC 1.11.1.7) activity and a higher percentage of fine roots with diameter between 0 < L ≥ 0.2 mm (particularly active in water and nutrient acquisition). In conclusion, results showed that vermicompost effectively reduced Cu phytotoxicityin young vines grown in soils with high Cu contents. Furthermore, this amendment might be an asset in enhancing the availability of other important micronutrients such as iron.
Assuntos
Compostos de Cálcio/farmacologia , Cobre , Fazendas , Silicatos/farmacologia , Solo , Vitis/crescimento & desenvolvimentoRESUMO
The occurrence of high levels of Cu in vineyard soils is often the result of intensive use of fungicides for the preventive control of foliar diseases and can cause toxicity to plants. Nowadays many grape growers in Southern Brazil have replaced Cu-based with Zn-based products. The aim of the study was to evaluate whether the increase in Zn concentration in a soil with high Cu contents can interfere with the dynamics of these elements, and if this increase in Zn may cause toxicity to maize (Zea mays L.). Soil samples were collected in two areas, one in a vineyard with more than 30 years of cultivation and high concentration of Cu and the other on a natural grassland area adjacent to the vineyard. Different doses of Cu and Zn were added to the soil, and the adsorption isotherms were built following the Langmuir's model. In a second experiment, the vineyard soil was spiked with different Zn concentrations (0, 30, 60, 90, 180, and 270mg Zn kg(-1)) in 3kg pots where maize was grown in a greenhouse for 35 days. When Cu and Zn were added together, there was a reduction in the quantities adsorbed, especially for Zn. Zn addition decreased the total plant dry matter and specific leaf mass. Furthermore, with the increase in the activity of catalase, an activation of the antioxidant system was observed. However, the system was not sufficiently effective to reverse the stress levels imposed on soil, especially in plants grown in the highest doses of Zn. At doses higher than 90Znmgkg(-1) in the Cu-contaminated vineyard soil, maize plants were no longer able to activate the protection mechanism and suffered from metal stress, resulting in suppressed dry matter yields due to impaired functioning of the photosynthetic apparatus and changes in the enzymatic activity of plants. Replacement of Cu- by Zn-based fungicides to avoid Cu toxicity has resulted in soil vineyards contaminated with these metals and damaging of plant photosynthetic apparatus and enzyme activity.
Assuntos
Cobre , Poluentes do Solo , Zea mays/efeitos dos fármacos , Zinco , Adsorção , Brasil , Cobre/química , Cobre/toxicidade , Fazendas , Fungicidas Industriais , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Solo/química , Poluentes do Solo/química , Poluentes do Solo/toxicidade , Vitis , Zea mays/crescimento & desenvolvimento , Zinco/química , Zinco/toxicidadeRESUMO
Soils used for the cultivation of grapes generally have a long history of copper (Cu) based fungicide applications. As a result, these soils can accumulate Cu at levels that are capable of causing toxicity in plants that co-inhabit the vineyards. The aim of the present study was to evaluate growth parameters and oxidative stress in black oat plants grown in vineyard soils contaminated with high levels of Cu. Soil samples were collected from the Serra Gaúcha and Campanha Gaúcha regions, which are the main wine producing regions in the state of Rio Grande do Sul, in southern Brazil. Experiments were conducted in a greenhouse in 2009, with soils containing Cu concentrations from 2.2 to 328.7 mg kg(-1). Evaluated parameters included plant root and shoot dry matter, Cu concentration in the plant's tissues, and enzymatic and non-enzymatic biochemical parameters related to oxidative stress in the shoots of plants harvested 15 and 40 days after emergence. The Cu absorbed by plants predominantly accumulated in the roots, with little to no translocation to the shoots. Even so, oat plants showed symptoms of toxicity when grown in soils containing high Cu concentrations. The enzymatic and non-enzymatic antioxidant systems of oat plants were unable to reverse the imposed oxidative stress conditions.
Assuntos
Avena/efeitos dos fármacos , Cobre/farmacologia , Fungicidas Industriais/farmacologia , Poluentes do Solo/farmacologia , Antioxidantes/metabolismo , Avena/química , Avena/fisiologia , Brasil , Cobre/metabolismo , Fungicidas Industriais/metabolismo , Especificidade de Órgãos , Estresse Oxidativo , Raízes de Plantas/química , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/fisiologia , Solo/química , Poluentes do Solo/metabolismo , VitisRESUMO
Grapevines grown on acid soils with low fertility in southern Brazil are treated with intense foliar applications of copper (Cu) fungicides, resulting in an increased level of Cu in the soil and increased toxicity. The present study evaluated the accumulation and bioavailability of Cu, and soils with varying levels of Cu from the main producing regions of southern Brazil were collected. The forms of Cu present in the soil were assessed using chemical extractants; additionally, oat cultivation was performed, reflecting the use of the plant as an indicator of Cu bioavailability. Cu accumulated in the topsoil, mainly in bioavailable forms, and there was also an increase of Cu up to a depth of 0.4 m. Cu was primarily found in the mineral fraction, with apparent saturation of the soil organic matter functional groups. Inceptisol and Alfisol soils with a long history of cupric fungicide application were found to have levels of Cu toxic to oat plants. Furthermore, accumulated copper in Alfisol soil from the Campanha Gaúcha region of the state of Rio Grande do Sul had higher bioavailability compared to Cu accumulated in Inceptisol soil from the Serra Gaúcha region. In addition, the copper concentration in roots was found to serve as an indicator of Cu bioavailability in soil, but not of copper phytotoxicity in plants.