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The conversion of Pampa Biome soils into no-till system for grain production requires acidity correction, at least to fully neutralize exchangeable aluminum (Al). The aim of the study is to...

The use of copper (Cu)-based fungicides to control diseases in vineyards can cause excessive Cu accumulation in soils. Greater Cu availability is expected in acid sandy soils with low organic matter (OM), where the risk of toxicity to plants and environment contamination is high. This study aimed to study the evolution of Cu in acid, sandy soils planted with grapevines for a period of time between 2 and 32 years. Two studies were carried out in South Brazil: in the first study, soil samples, from 19 vineyards were collected and analyzed in the first 0.2 m depth-layer for the total and available Cu. In the second study, 3 soils were selected among the previous 19 according to the age of vineyard (5, 11, and 30 year-old), and their 0.60 m-depth profile was analyzed for 5 fractions of Cu (soluble, exchangeable, mineral, organic, and residual). All the soils were classified as Ultisols. The vineyards with more than 25 years under cultivation had a mean total Cu concentration of 90 mg kg−1 in the 0–0.10 m layer. Approximately 80% of it was potentially available to plants. The greatest total and available Cu were found in the soil surface layers (0.2 m depth), where up to 75% of the total Cu is adsorbed in clay minerals and only 20% is complexed in the OM.

The continuous use of copper-based fungicides in viticulture to contrast fungal diseases may result into an accumulation of Cu in the topsoil, reaching toxicity levels for plants and soil biota. A possible strategy to mitigate the negative effects of excess of Cu could involve the formation of insoluble molecules by the application of P to the soil. The aim of this study was to evaluate the effectiveness P soil application as a strategy to alleviate the toxic effect of excess of Cu on potted grapevines plants, with particular emphasis on the physiological response of plants. Micropropagated plants of 1103 Paulsen rootstock were grown according to a factorial experimental design with two factors: Cu (4 levels: 0, 100, 200, 300 mg kg−1 dw) and P (2 levels: 0 and 100 mg kg−1 dw) and three replicates. Net photosynthesis, efficiency of PSII photochemistry and linear electron transport rate decreased as soil Cu concentration increased. The addition of P increased net photosynthesis, improved the efficiency of PSII photochemistry and linear electron transport rate, but decreased stomatal conductance. As a consequence, shoot and root biomass declined with the increase of Cu concentration in soil, while the increment of P tackled this decline and improved nutritional status. CuEDTA extractable fraction in soil was increased by both the supply of Cu and P; this because the addition of P in combination with the highest Cu soil concentration determined a decrease of soil pH. In conclusion, the addition of P to the soil mitigated Cu excess toxicity symptoms in grape through a preservation of photosynthetic apparatus efficiency and an improvement of nutrient uptake.

Urea and organic compost are applied as a nitrogen (N) source in vineyards. The aim of this study was to evaluate the yield, total N content in the leaves and the must composition in grapevines with the application of organic compost and urea. ‘Cabernet Sauvignon’ grapevines, in the 2008/2009 and 2009/2010 crop seasons were subjected to the application of 40 kg N ha-1 in the form of organic compost and urea; but there were also unfertilized grapevines. In both crop seasons, leaves were collected at the stages of full flowering and at the change in color of the berries, and the total N content were analyzed; grape yield was evaluated and enological attributes were determined in the must. The application of organic compost and urea did not affect the N content in the leaf nor the grape yield in the second crop season evaluated. However, in the first crop season, grape yield was greater in the grapevines with application of organic compost to the soil. The addition of N sources did not affect the total nutrient content in the must but, in the second crop season, the grape must from the grapevines with the addition of organic compost had a lower soluble solids concentration and a higher total acidity value, as well as tartaric and malic acid values.

The aim of the present study was to evaluate the effectiveness of P soil addition to mitigate the toxic effect of excess of Cu on grapevine on sandy non-calcareous soil. Micro-propagated plants of 1103 Paulsen rootstock were grown according to a factorial experimental design with two factors: Cu addition (0, 100, 200 and 300 mg kg −1 dw) and P addition (0, 50 and 100 mg kg −1 soil dw). The experiment was conducted in the greenhouse and plants were grown on a sandy soil in rhizoboxes. At the end of the trial, plants were destructively harvested, the biomass and the nutrient concentration of organs were determined. Root growth was evaluated during the trial and the concentration of organic acid in root tissue and exudates was determined. Shoot length and plant biomass declined as Cu concentration in soil increased; the application of P enhanced plant growth and nutritional status. Root biomass decreased at Cu > 100 mg kg −1 and increased in P at 100 mg kg −1 . Phosphorous stimulated root length, diameter and the number of apexes. Root citric acid increased as a response of Cu at 300 mg kg −1 , root ascorbic acid decreased with the increase of Cu (200 and 300 mg kg −1 ) and P at 100 mg kg −1 . The concentration of citric acid from root exudations was higher in Cu at 300 mg kg −1 and Cu at 200 mg kg −1 (compared to control) and P at 100 mg kg −1 soils. The application of P fertilization seems to be a valuable strategy to overcome the toxicity of high concentration of Cu in soil.

The purpose of this study was to evaluate Cu and Zn migration and fractions in sandy soil of vineyards. In Urussanga (SC), Brazil, soil samples were collected from a 4-year-old and 15-yearold vineyard, and from a forested area. In the soils, the chemical characteristics of Cu and Zn were analyzed by the EDTA method, which determines the fraction available in soil; 3050B method of the USEPA for total concentrations, which represents the pseudosoil contents in the soil; and chemical fractionation, which estimates soluble fraction, exchangeable fraction, fraction associated with clay minerals, fraction associated with organic matter and residual fraction. The results show that there is accumulation of Cu and Zn in sandy soils cultivated with grapevines and with frequent fungicide applications. These higher levels were found in soils with longer cultivation time (15 years old), but were restricted to the superficial layers of the soil. Most of the Cu was extracted by EDTA method, and it may be considered as available to plants. The EDTA also extracted a small part of Zn. Most of the Cu in the vineyard soils can be characterized by low geochemical mobility, but in the uppermost soil layers of the oldest vineyard, there was an increase in Cu content associated with soil organic matter. Most of the Zn in the vineyard soil was associated with minerals, which indicates low mobility and also low potential for toxicity to plants and microorganisms. Key words: availability, chemical fractionation, toxicity, environmental contamination, Vitisvinifera. Made available in DSpace on 2019-01-09T23:53:16Z (GMT). No. of bitstreams: 1 Copperandzincaccumulationfractionation.pdf: 618556 bytes, checksum: 35756820009ffff730b38562c1ef7af3 (MD5) Previous issue date: 2019-01-09

This study aimed to assess the effect of liming as an ameliorator of copper (Cu) toxicity in black oats (Avena strigosa Schreb.) grown in soil with a sandy texture. The treatments were soil supplementation with increasing doses of lime (0.0, 0.5 and 1.0 g kg−1) and two of Cu (0 and 50 mg kg−1). Pre-germinated black oat seeds were sown for 30 days in the soil, subsequently, the plant height, root and shoot dry mass and concentration of total chlorophyll, chlorophylls a and b, carotenoids and total soluble carbohydrates and starch were analyzed. The dose of 50 mg kg−1 soil Cu caused a toxic effect on black oat plant growth and development, affected the internal distribution of nutrients, decreased the leaf chlorophyll concentration and increased the leaf concentration of total soluble carbohydrates and starch. Increasing lime doses ameliorated the toxic effects of Cu.

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.

Little is known about the impact of N fertilization on fruit production and composition in orange groves grown in soils with low or medium organic matter content in Rio Grande do Sul (RS). This study aimed to evaluate how N fertilization of orange trees cv. 'Lane Late' in a sandy soil may interfere in fruit yield and composition of fruit and juice. The experiment was conducted with orange trees cv. 'Lane Late' growing in Sandy Typic Hapludalf soil, in Rosário do Sul (RS). The plants received applications of 0, 20, 40, 60, 80, 100, 120, 140 and 160kg N ha-1. Total N in leaves, number of fruits per plant, yield, fresh weight, fruit diameter, peel thickness, percentage of fruit juice, peel color, juice color, ascorbic acid content, total soluble solids (TSS) and total titratable acidity were evaluated in 2010/2011 and 2011/2012 crops. In the first crop, especially yield, number of fruits per plant, TSS content in fruit juice and ratio decreased with increasing N rate applied. However, in the second crop, the total titratable acidity of the fruit juice prominently increased with the dose of N applied. In both crops, results were highly influenced by rainfall distribution, which affect the plant physiology, soil N dynamics and, consequently, probability of response to N applied and the loss of mineral N in the soil.

Successive applications of copper-based (Cu) fungicides have increased Cu concentration in vineyard soils, inducing Cu toxicity in young vines and cover crops such as black oat, thus inhibiting growth and development. However, increasing soil phosphorus (P) content can reduce Cu toxicity symptoms. In this context, the aim of this study was to evaluate the effect of Cu toxicity and its alleviation by P fertilization in black oat cultivated in sandy soil. For the experiment, Typic Hapludalf soil samples were air-dried, prepared, and subjected to increasing doses of Cu (0, 30, and 60 mg kg−1) and P (0 and 100 mg kg−1). Subsequently, the soil was incubated and stored in pots, where black oat seedlings were grown for 30 days in a greenhouse. Plant roots subjected to Cu, especially with the highest Cu concentration and without P addition decreased the root cap size, showing early tissue differentiation and lateral root formation near the apical region. Decrease in dry matter (DM) production of roots (50 %) and shoots (67 %) was also observed in the highest Cu concentration. Plants without P addition, regardless of Cu concentration, also had lower root (33 %) and shoot (65 %) DM production. P addition in soil and its increased concentration reduced root anatomical changes and stimulated plant DM production. Therefore, we conclude that excessive Cu concentration alters black oat root anatomical structure, affecting plant growth, especially in sandy soils with low organic matter content. However, P supply can reduce root Cu toxicity symptoms, thus increasing plant dry matter production.