Copper uptake, accumulation and physiological changes in adult grapevines in response to excess copper in soil.

Publicada online em 24 de setembro

Long-term effect of different soil management systems and winter crops on soil acidity and vertical distribution of nutrients in a Brazilian Oxisol

“Strategies” to sustain crop productivity by reducing the fertilizer and lime demands must be developed. The use of plant species that use more efficiently the soil nutrients and tillage systems that provide nutrients accumulation in more labile forms are prerequisites for sustainable agroecosystems. This study aimed to evaluate the long period effect of cultivating different winter species under different soil management systems on vertical distribution of soil nutrients and the soil acidity distribution in soil profile. The experiment was established in 1986 with six winter treatments (blue lupine, hairy vetch, oat, radish, wheat and fallow) under conventional tillage (CT) and no-tillage (NT) in a very clayey Rhodic Hapludox in Southern Brazil. As a result of 19 years of no soil disturbance, soil chemical attributes related to soil acidity and the availability of P and K were more favorable to crops growth up to 10 cm in the soil under no-tillage than in the conventional tillage. On other hand, lime applications in low doses on the soil surface were not efficient in neutralizing the aluminum toxicity below 10 cm depth. It shows that repeated use of lime on the soil surface under NT system can be a viable alternative strategy only when soil acidity and aluminum toxicity in subsurface has been previously eliminated using the adequate amount of lime and incorporating it into the arable layer. Moreover, in the conventional tillage system P and K availability were higher below 10 cm depth compared to the no-tillage system. Even after 19 years of no soil disturbance in the NT system the available P content below 10 cm soil layer was lower than the optimal content of available P recommended to cash crops. The reduced surface K application over time was sufficient to gain adequate crop yields and to maintain the optimal content of soil available K in both soil management systems. The effects of soil management systems were predominant on the soil acidity attributes, and no effects of winter cover crops were observed on soil acidity attributes. Black oat and blue lupine were more efficient in P cycling, increasing the soil available P content especially in the surface soil under NT. The lower amount of biomass produced over time when no cover crops were used in the winter period resulted in lower P and K availability in the soil, showing the important role of growing winter species to maintain soil fertility

Phosphorus fractions in sandy soils of vineyards in Southern Brazil.

As aplicações de fósforo (P) em vinhedos podem causar o acúmulo desse nutriente no solo e maximizar seu potencial poluente. Este trabalho objetivou quantificar as frações de acumulação de P em solos arenosos cultivados com videiras na região Sul do Brasil. Para isso, amostras de solo foram coletadas nas camadas de 0-5, 6-10 e 11-20 cm em uma área de campo nativo e em dois vinhedos: um com 14 anos de cultivo (vinhedo 1) e outro com 30 anos (vinhedo 2), localizados no município de Santana do Livramento, Rio Grande do Sul (RS), Brasil. As amostras foram secas, moídas e submetidas ao fracionamento químico de P. Os resultados evidenciaram que os teores de P inorgânico aumentaram até 20 cm de profundidade, principalmente no vinhedo 2, em especial nas frações lábeis extraídas por resina de troca aniônica e por NaHCO3, na fração moderadamente lábil, extraída por NaOH 0,1 e 0,5 mol L-1, e na fração não lábil, extraída por HCl 1 mol L-1, representando potencial de eutroficação das águas. As aplicações de fertilizantes fosfatados na adubação de correção e de manutenção nos vinhedos com maior tempo de cultivo aumentaram os teores de P na fração orgânica extraída por NaHCO3 na camada de 0-5 cm, e na fração moderadamente lábil extraída por NaOH 0,1 mol L-1, até 20 cm de profundidade

Establishment of potassium reference values using Bayesian models in grapevines

Critical levels (CL) of available potassium (K) in soils and leaves and maximum technical efficiency (MTE) doses are relevant information to define the best K fertilization strategies. The aim of this study was to determine reference values of K in leaves and soil, using Bayesian analysis, in order to maximize grape yield and must quality of ‘Chardonnay’ and ‘Pinot Noir’ grown in a subtropical climate. The vines were subjected to applications of 0, 20, 40, 60 and 80 kg K2O ha−1 year−1. The CL and MTE doses of K, in leaves and soils, were determined using Bayesian hierarchical models. The range of probability of the occurrence of CL in leaves was 15.8 to 18.9 g K kg−1 in ‘Chardonnay’ and 16.8 to 19.1 g K kg−1 in ‘Pinot Noir’ at flowering. Moreover, the range was 15.3 to 18.1 g K kg−1 in ‘Chardonnay’ and 16.1 to 18.2 g K kg−1 in ‘Pinot Noir’ at veraison. In the soil, the CL of available K for ‘Chardonnay’ was 27.4 mg K kg−1 and for ‘Pinot Noir’ it was 23.2 mg K kg−1. The increase of K in leaves and soil increased the TSS, while the TTA decreased in both cultivars after sufficiency rate. The MTE was estimated in ‘Pinot Noir’. The proposition of CL and/or MTE doses of K can help increase the efficiency of K fertilization in vineyards

Acúmulo de cobre e zinco em solos cultivados com videira no meio Oeste de Santa Catarina.

As aplicações sucessivas de fungicidas e caldas via foliar em videiras para o controle preventivo de doenças fúngicas, aumenta o teor de cobre (Cu) e zinco (Zn) nas camadas mais superficiais do solo. O trabalho objetivou avaliar os teores de Cu e Zn no perfil de solos com textura argilosa e com histórico de aplicação de fungicidas cúpricos na região Meio Oeste de SC. Em outubro de 2010, foram selecionados três vinhedos com idades de 4, 6 e 10 anos de idade, no município de Água Doce (SC). Em novembro de 2010 foram coletadas amostras de solo nas camadas de 0-5, 5-10, 10-15, 15-20 e 20-40 cm. Também foi coletado solo em uma área de mata nativa, adjacente aos vinhedos. Os solos foram secos, moídos, passados em peneira e submetidos as análises de Cu e Zn extraídos pelos métodos de EDTA (Na2-EDTA 0,01 mol L-1+acetato de amônio 1,0 mol L-1) com pH ajustado para 7,0. Os teores de Cu e Zn extraídos por HCl 0,1 mol L-1 e EDTA foram maiores nas camadas superficiais do solo, especialmente, no vinhedo mais antigo, onde o Cu migrou até 20 cm e o Zn até 15 cm.Resumo expandido

Use of phosphorus fertilization and mycorrhization as strategies for reducingcopper toxicity in young grapevines.

Established vineyard soils may have high copper (Cu) contents due to the ongoing foliar applications of copper-based fungicides. In viticulture, the replacement of old vineyards with new vines is common practice, however,limited by Cu excess in soil and its toxicity to young grapevines. The application of phosphorus (P) and ar-buscular mycorrhizal fungi (AMF) inoculation are potential strategies to reduce Cu toxicity to young grapevines.This study aimed to assess the effects of phosphorus fertilization and AMF (Rhizophagus clarus) inoculation ongrowth and physiological parameters of young grapevines grown in soil with high Cu content. The experimentwas conducted in a greenhouse, where natural grassland soil was artificially contaminated by the addition of60 mg kg−1Cu. The soils were treated with and without AMF inoculation, combined with additions of 0, 40 and100 mg P kg−1. After 90 days of cultivation, grapevine plants were assessed for chlorophyllafluorescence,photosynthetic pigment contents, superoxide dismutase (SOD) activity, plant height, plant biomass, and con-centrations of Cu and P in roots and shoots. Phosphorus fertilization promoted increases in seedling growth(related to the increase of total P concentration in roots and shoots), soluble Pi concentration in leaves, and thequantum yield of the PSII (YII) (associated with a reduction in shoot Cu concentration). The AMF inoculationincreased the concentration of P in roots and shoots, soluble Pi in leaves and electron transport rate (ETR).Phosphorus fertilization and inoculation of grapevines with AMF are strategies capable of reducing Cu toxicity inyoung grapevines

Perspectivas futuras sobre a contaminação em solos de vinhedos, pomares e toxidez em plantas.

A fruticultura é uma atividade agrícola de grande importância econômica e social no Brasil. As frutíferas, como a videira, quando cultivadas em solos que n~]ao possuem capacidade de disponibilizar a quantidade suficiente de nutrientes Às plantas são submetidas a aplicações de fertilizantes

Uso do SPAD no diagnóstico do teor total de nitrogênio na folha em videiras submetidas à adubação nitrogenada na Serra Gaúcha do Rio Grande do Sul.

A leitura do SPAD pode ser um eficiente método de estimativa do teor total de nitrogênio (N) em folhas completas de videiras. Com isso, se pode inferir sobre o estado nutricional da planta e a necessidade da adubação nitrogenada. O presente trabalho teve como objetivo estabelecer a relação entre o teor total de N na folha completa, coletada em duas épocas e a leitura do SPAD. O experimento foi conduzido na safra de 2008/09, em vinhedo de viníferas Cabernet Sauvignon, na área experimental da Embrapa Uva e Vinho, em Bento Gonçalves (RS), sobre um Neossolo Litólico. Foram aplicadas as doses 0, 10, 20, 40 e 80kg ha-1 de N. No florescimento e na mudança da cor das bagas foram realizadas leituras com o SPAD e, em seguida, as folhas completas foram secas, moídas e preparadas para a análise do total de N. Os resultados mostraram que as leituras de SPAD (equipamento Minolta-SPAD- 502), podem ser usadas para estimar o teor total de N em folhas completas de videiras no florescimento e na mudança da cor das bagas, permitindo o estabelecimento da necessidade de aplicação do nutriente