Lessandro De Conti

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

AimsThis study investigated Cu uptake and accumulation as well as physiological and biochemical changes in grapevines grown in soils containing excess Cu.MethodsThe grapevines were collected during two productive cycles from three vineyards with increasing concentrations of Cu in the soil and at various growth stages, before and after the application of Cu-based fungicides. The Cu concentrations in the grapevine organs and the macronutrients and biochemical parameters in the leaf blades were analyzed.ResultsAt close to the flowering stage of the grapevines, the concentration and content of Cu in the leaves were increased. However, the Cu concentrations in the roots, stem, shoots and bunches did not correlate with the metal concentrations in the soil. The application of Cu-based fungicides to the leaves increased the Cu concentrations in the shoots, leaves and rachis; however, the effect of the fungicides on the Cu concentration in the berries was not significant. The biochemical analyses of the leaf blades demonstrated symptoms of oxidative stress that correlated with the Cu concentrations in soil.ConclusionsThe increased availability of Cu in soil had a slight effect on the levels and accumulation of Cu in mature grapevines during the productive season and did not alter the nutritional status of the plant. However, increased Cu concentrations were observed in the leaves. The evidence of oxidative stress in the leaves correlated with the increased levels of Cu in soil.

Frações de fósforo no solo após sucessivas aplicações de dejetos de suínos em plantio direto

The objective of this work was to quantify the accumulation of phosphorus fractions in the soil subjected to successive pig slurry applications in a no-tillage system. At Santa Maria, Rio Grande do Sul state, Brazil, 0, 20, 40 and 80 m3 ha-1 doses of pig slurry were broadcasted for seven years on Argissolo Vermelho arenoso (Arenic Hapludult) before sowing each winter or summer crop, totalizing 0, 584, 1,168 and 2,336 kg ha-1 of P from pig slurry. Soil samples were collected in 0-2, 4-6, 8-10, 14-16 and 20-25 cm layers and submitted to P fractionation. Applications of pig slurry during seven years increased P contents to a depth of 25 cm, especially in the inorganic fractions extractable by anion exchange resin, NaHCO3 0.5 mol L-1 and NaOH 0.1 mol L-1. Pig slurry doses did not increase P content in organic fractions extracted by NaHCO3 0.5 mol L-1, but increased the content of organic fractions extracted by NaOH 0.5 e 0.1 mol L-1. Pig slurry applied to soil for large period has little effect on the P partition in inorganic and organic fractions. Successive pig slurry applications increase P contents in the soil predominantly in labile fractions, which can represent a potential risk for waterbeds contamination.

Nutrients in soil layers under no-tillage after successive pig slurry applications

Successive applications of pig slurry to soils under no-tillage can increase the nutrient levels in the uppermost soil layers and part of the nutrients may be transferred to deeper layers. The objective was to evaluate the distribution of nutrients in the profile of a soil after 19 pig slurry applications under no-tillage for 93 months. The experiment was conducted from May 2000 to January 2008 in an experimental area of the Federal University of Santa Maria, southern Brazil, on a Typic Hapludalf. The treatments consisted of pig slurry applications (0, 20, 40 and 80 m3 ha-1) and at the end of the experiment, soil samples were collected (layers 0-2, 2-4, 4-6, 6-8, 8-10, 10-12, 12-14, 14-16, 16-18, 18-20, 20-25, 25-30, 30-35, 35-40, 40-50 and 50-60 cm). The levels of mineral N, available P and K and total N, P and K were evaluated. The 19 pig slurry applications in 93 months promoted migration of total N and P down to 30 cm and available P and K to the deepest layer analyzed. At the end of the experiment, no increase was observed in mineral N content in the deeper layers, but increased levels of available P and K, showing a transfer of N, P and K to layers below the sampled. This evidences undesirable environmental and economic consequences of the use of pig slurry and reinforces the need for a more rational use, i.e., applications of lower manure doses, combined with mineral fertilizers.

Triggered antioxidant defense mechanism in maize grown in soil with accumulation of Cu and Zn due to intensive application of pig slurry

The present study investigated changes in both the growth parameters and the enzymatic and non-enzymatic antioxidant systems of maize (Zea may L.) plants grown in Typic Hapludalf soil containing an accumulation of Cu and Zn. This accumulation developed because the soil received nineteen applications of pig slurry in no-tillage system over seven years. In this study, the maize plants were grown for fifteen and 25 days after emergence (DAE) in pots containing undisturbed and disturbed soil samples collected from a field experiment that received the rates 0, 20, 40 and 80m(3)ha(-1) of pig slurry, which totalized the amount of 0, 380, 760 and 1520m(3)ha(-1) of pig slurry in seven years, respectively, and phosphorus (P)+potassium (K) treatment (in disturbed soil samples). The maize plants grown in the undisturbed soil samples with an accumulation of Cu and Zn did not indicate an apparent decrease in growth. However, when compared to the treatment with PK fertilization, the maize plants grown in the disturbed soil with pig slurry treatments indicated higher lipid peroxidation and a number of senescent leaves, as well as a significant decrease in plant height. Additionally, when compared to the PK treatment, the leaf superoxide dismutase and ascorbate peroxidase activities decreased and increased, respectively, with the addition of pig slurry treatments in the disturbed soil at 25 DAE. In general, when compared to the treatments with 20m(3)ha(-1) of pig slurry and PK at fifteen and 25 DAE, the leaf ascorbic acid and non-protein thiol groups concentrations decreased with the addition of 40 and 80m(3)ha(-1) of pig slurry. This result suggests that the excess of Cu and Zn in the pig slurry significantly changed the antioxidant system of the maize plants.

Lixiviação e volatilização de nitrogênio em um Argissolo cultivado com videira submetida à adubação nitrogenada

Nitrogen (N) applied in vineyards may be lost through volatilization or lixiviation. Two experiments were carried out to evaluate the N losses through volatilization or lixiviation in vineyard submitted the N fertilization, at Sandy Typic Hapludalf soil in Southern Brazil. In the experiment 1, the treatments were applications of 0, 40, 80 and 120kg N ha-1, as urea form, and analyze N concentration in soil solution. The soil solution was collected by lysimeters during the cycle of the grapevines. In the experiment 2, the treatments were 0, 20, 40, and 80kg N ha-1, as urea form, 40kg ha-1 N as composed organic form and 40kg N ha-1 as urea covered with polymer to evaluate ammonia volatilization until 80 hours after N fertilization. The largest concentration of mineral nitrogen were detected in the leach solution from treatments of higher doses of mineral fertilizer, along the budding and along the flowering of grapevines and this factors may decrease the nutrient efficiency. The largest flows and losses of ammonia to the atmosphere from a soil cultivated with grapevines happened at treatments with highest doses of mineral nitrogen. The highest lose happened 44 hours after fertilizer application on soil surface. The application of urea coated with polymers and organic compounds showed the smallest ammonia losses by volatilization, which may improve nitrogen efficiency by grapevines.

Accumulation and distribution of copper and zinc in soils following the application of pig slurry for three to thirty years in a microwatershed of southern Brazil

The application of pig slurry to soil can result in the accumulation of soil Cu and Zn, alter soil Cu and Zn fractions, and result in soil, surface water, and subsurface water contamination. This study evaluated the accumulation and distribution of Cu and Zn in soil profiles from 10 areas treated with pig slurry for 3–30 yr. A microwatershed within the municipality of Braço do Norte in the state of Santa Catarina and in the southern region of Brazil was studied. Hapludalf soil samples were collected at depths of 0.0–0.05, 0.05–0.10, 0.10–0.20, 0.20–0.30, and 0.30–0.40 m from 10 areas where pig slurry had been applied for 3–30 yr. The soil samples were dried, prepared, and analyzed to determine their chemical characteristics, particularly to quantify their Cu and Zn fractions. Although long-term pig slurry application resulted in greater available Cu and Zn concentrations in the surface soil layer, the migration of available Cu in the soil profile only occurred in areas that were subjected to more than 17 yr of slurry application. The application of pig slurry increased the available Cu and Zn contents in the surface soil layer; however, the available Cu in the soil profile increased in the areas with more than 17 yr of slurry application. Cu accumulation mainly occurred in the organic and mineral soil fractions, and Zn accumulation mainly occurred in the mineral fraction. Overall, Cu posed a greater risk for surface water contamination than Zn, especially in areas with more than 17 yr of pig slurry application.

Biochemical changes in black oat (avena strigosa schreb) cultivated in vineyard soils contaminated with copper

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 plants 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.

Phosphorus fractions in soil after sucessive pig slurry applications in no-tillage system

The objective of this work was to quantify the accumulation of phosphorus fractions in the soil subjected to successive pig slurry applications in a no-tillage system. At Santa Maria, Rio Grande do Sul state, Brazil, 0, 20, 40 and 80 m3 ha-1 doses of pig slurry were broadcasted for seven years on Argissolo Vermelho arenoso (Arenic Hapludult) before sowing each winter or summer crop, totalizing 0, 584, 1,168 and 2,336 kg ha-1 of P from pig slurry. Soil samples were collected in 0-2, 4-6, 8-10, 14-16 and 20-25 cm layers and submitted to P fractionation. Applications of pig slurry during seven years increased P contents to a depth of 25 cm, especially in the inorganic fractions extractable by anion exchange resin, NaHCO3 0.5 mol L-1 and NaOH 0.1 mol L-1. Pig slurry doses did not increase P content in organic fractions extracted by NaHCO3 0.5 mol L-1, but increased the content of organic fractions extracted by NaOH 0.5 e 0.1 mol L-1. Pig slurry applied to soil for large period has little effect on the P partition in inorganic and organic fractions. Successive pig slurry applications increase P contents in the soil predominantly in labile fractions, which can represent a potential risk for waterbeds contamination.

Disponibilidade de nitrogênio de fontes minerais e orgânicas aplicadas em um Argissolo cultivado com videira

Nitrogen availability of organic and mineral sources applied in Sandy Typic cultivated with vine

Crop response to organic fertilization with supplementary mineral nitrogen

Animal manure is applied to the soil as a nutrient source, especially of nitrogen, to plants. However, manure application rates can be reduced with the use of N fertilizer in topdressing. The aim of this study was to evaluate crop responses to different application rates of animal manure sources, used alone and supplemented with mineral N topdressing, in a no-tillage system. The study was carried out from 2005 to 2008 on a Hapludalf soil. The treatments consisted of rates of 10, 20 and 30 m3 ha-1 of pig slurry (PS), and of 1 and 2 t ha-1 of turkey manure (TM), applied alone and supplemented with topdressed N fertilizer (TNF), as well as two controls, mineral fertilization (NPK) and one control without fertilizer application. Grain yield in common bean and maize, and dry matter yield and nutrient accumulation in common bean, maize and black oat crops were evaluated. Nitrogen application in topdressing in maize and common bean, especially when PS was used at rates of 20 and 30 m3 ha-1, and TM, at 2 t ha-1, proved effective in increasing the crop grain yields, showing the viability of the combined use of organic and industrialized mineral sources. Nitrogen accumulation in maize and common bean tissues was the indicator most strongly related to grain yield, in contrast with the apparent nutrient recovery, which was not related to the N, P and K quantities applied in the organic sources. No clear residual effect of N topdressing of maize and common bean was observed on the dry matter yield of black oat grown in succession to the main crops with PS and TM applications.