Resumo A adubação potássica pode modificar as formas de K no solo, influenciando a absorção pela planta e a produtividade, mas principalmente a composição da uva. O objetivo do presente estudo foi avaliar o impacto da fertilização com potássio (K) na uva, a produção e a composição do mosto de uva da cultivar ‘Cabernet Sauvignon’. As videiras foram tratadas com 0; 50; 100; 150 e 200 kg ha-1 ano-1 de K2O. Foram avaliados os teores de K na folha, a produção de uva por planta e por área, os sólidos solúveis totais (SST), o pH do mosto e a acidez titulável no mosto, e o K disponível no solo. Amostras de solo coletadas na camada superficial de 20 cm foram analisadas para medir a disponibilidade de K e o K não trocável, com base em estudos conduzidos ao longo de 3 safras. Os resultados mostraram, pela análise das três safras da videira, que a aplicação de K não afetou a produção e a composição do mosto, embora tenha aumentado o teor de K na folha. No entanto, o fracionamento anual de K do solo sugere que 100 kg ha-1 ano-1 de K2O é a dose de K capaz de manter a disponibilidade do nutriente para as plantas em teores mais adequados ao longo das estações de cultivo.

Abstract Potassium fertilization can change K forms available in the soil, as well as influence plant absorption of it and yield but, mainly, it can affect grape composition. The aim of the current study was to investigate the impact of potassium (K) fertilization on grape production and juice (must) composition of a Cabernet Sauvignon cultivar. Grapevines were treated with 0, 50, 100, 150 and 200 kg ha-1 year-1 K2O. Leaf K contents, grape yield per plant and area, total soluble solids (TSS), must pH and titratable acidity, and K available in the soil were assessed. Soil samples collected at the 20-cm layer were analyzed to measure K availability and nonexchangeable K in them, based on studies conducted over 3 growing seasons. Results have shown that K application did not have effect on grape production and must composition, although it increased K contents in leaf blade and petiole. However, annual K fractionation in the soil has suggested that 100 kg ha-1 year-1 K2O is the K dose capable of maintaining K availability to plants at more appropriate contents throughout the growing seasons.

ABSTRACT The aims of the current study are to (a) evaluate the growth and nutritional status of young Chardonnay and Pinot Noir vines grown in soil subjected to K application and (b) to determine the growth and nutritional status of young Chardonnay vines grown in soil subjected to K and to different limestone applications. The experiment was conducted in Red Argisol, in Santana do Livramento County (RS), in crop seasons from 2011/12 to 2013/14. Treatments adopted in experiment 1 comprised 0, 30 and 60 kg of ha-1. Variables K exchangeable content in the soil, K content in leaves, plant height, stem diameter and weight of the pruned material were evaluated. Treatments adopted in experiment 2 comprised 0, 60, 120, and 180 kg of K2O ha-1, as well as calcitic and dolomitic limestone applications. Variables exchangeable K, Ca and Mg contents in the soil, K, Ca and Mg contents in leaves, plant height, stem diameter and weight of the pruned material were evaluated. Potassium fertilization increased the K content in the 0-10 cm layer and influenced the K content in leaves collected in the first crop; however, it did not influence growth parameters in Chardonnay and Pinot Noir cultivars. Potassium, dolomitic and calcitic limestone application enabled nutrient absorption by plants, whose leaves presented increased K content; however, it did not influence growth parameters in cultivar Chardonnay.

RESUMEN Los objetivos de este estudio fueron: (a) evaluar el crecimiento y el estado nutricional de las vides jóvenes cv. Chardonnay y Pinot Noir cultivadas en suelos donde se incorporó K; y (b) determinar el crecimiento y el estado nutricional de plantas juveniles de vid cv. Chardonnay cultivadas en suelos donde se incorporó K y diferentes dosis de cal. El experimento se realizó en Red Argisol, en el condado de Santana do Livramento (RS), en las temporadas de cultivo del 2011/12 al 2013/14. El tratamiento del Experimento 1 fue la incorporación de 0, 30 y 60 kg de K 2 O ha -1 . Se evaluó el contenido de K intercambiable en el suelo, contenido de K en las hojas, altura de la planta, diámetro del tallo y peso del material podado. El tratamiento del Experimento 2 fue la incorporación de 0, 60, 120 y 180 kg de K2O ha -1 , con aplicaciones de calcita y dolomita. Se evaluaron los contenidos de K, Ca y Mg intercambiables en el suelo, los contenidos de K, Ca y Mg en las hojas, la altura de la planta, el diámetro del tallo y el peso del material podado. Los resultados del Experimento 1 sugieren que la fertilización con potasio aumentó el contenido de K en la capa de 0-10 cm e influyó en el contenido de K en las hojas recolectadas en el primer cultivo. Sin embargo, no afectó los parámetros de crecimiento en los cultivares Chardonnay y Pinot Noir. Los resultados del Experimento 2 muestran que la aplicación de potasio, calcita y dolomita permitió la absorción de nutrientes de las plantas jóvenes, cuyas hojas presentaron un mayor contenido de K. Sin embargo, no influyó en los otros parámetros de crecimiento en el cultivar Chardonnay, ni en el contenido de Ca y Mg en las variables estudiadas.

ABSTRACT Soils with a long-term history of animal manure application exhibit higher residual effects of nitrogen (N) in soil and can affect the efficiency with which N will be used. This study aimed to evaluate how the immediate and residual effect of 16 applications of animal manure reflects on yields of black oat and corn rotation system, as well as N use efficiency. The study was carried out in no-tillage from 2004 to 2016 in Brazil. The treatments were pig slurry (PS), dairy slurry (DS), pig deep-litter (PL), mineral fertilizer (MF), and control (C). Prior to the sowing of black oat, in which 16 animal manure applications had already been made, an area of the soil was delimited where the treatments were not applied. This area was referred to as unfertilized (U) soil. Applications were carried out in the remaining area and were referred to as fertilized (F) soil. The highest dry matter yield and N accumulation in black oat and corn were found in F soils treated with DS and PL, respectively. In corn, the highest grain yield and N accumulation in grains were found with DS and PS. In U soil, the 16 applications (of DS especially) resulted in yields and N accumulation greater than the control and MF, but lower than those in F. The highest N use efficiency was found with DS. The history of animal manure applications was not enough to rule out additional applications in the following years.

ABSTRACT Fruit and vegetable waste can be used for the production of organic compost, which when mineralized can increase the availability of nitrogen. The objectives of this study were: (a) to produce compost from different ratios of fruit and vegetable waste, rice husk and poultry manure that meets the legislation on organic fertilizers and (b) to assess the mineralization of N in substrates prepared with different ratios of compost. In experiment 1, the following treatments were prepared using (fruit and vegetable residue: rice husk: poultry waste) (v:v): Treatment 1 (2:1:0), T2 (1:1:1), T3 (1.5:1:0) and T4 (1.2:1:0). All the treatments were subjected to composting for 95 days, were subjected to analysis of nutrients, organic carbon, C/N, CEC/C, pH and moisture content. The composts were compared in regards to the parameters required by legislation. In experiment 2, the treatments consisted of eight blends of agricultural peat, carbonized rice husk and organic compost pre-selected from experiment 1. The NO3 --N and NH+ 4-N contents were analyzed in the substrate at time zero and at 7, 14, 28, 56, 112 days after incubation. Compost (C2) met the parameters required by legislation and the use of 40% in the substrate composition promoted the mineralization of N.

RESUMO: A acidez potencial do solo pode ser medida por dois métodos nos estados do Rio Grande do Sul (RS) e Santa Catarina (SC): índice SMP ou solução TSM (Tampão Santa Maria). A calibração destes métodos é feita pela incubação de solos por longos períodos (180 dias) com quantidades crescentes de CaCO3. A hipótese deste estudo é que é possível reduzir o período de incubação em solos usando uma base solúvel como o hidróxido de cálcio. O trabalho objetivou estimar a acidez potencial em um grupo de solos por meio de incubação úmida com Ca(OH)2 (curta) como alternativa ao método típico com CaCO3 (longa) e relacionar com os valores estimados pela equação utilizada pela CQFS-RS/SC (2016). Dez solos com textura arenosa e baixo conteúdo de matéria orgânica foram coletados a 0-20cm na região da Campanha Gaúcha e incubados por 180 dias com doses de CaCO3 equivalentes a 0, 25, 50, 75, 100, 125 e 150% da exigência de calcário estimada pela solução TSM para elevar o pH a 6,0 (longa). Os solos foram também incubados por 4 dias em estufa a 35ºC com 0,22mol L-1 de Ca(OH)2 em doses equivalentes ao CaCO3 (curta). A incubação curta do solo com Ca(OH)2 pode substituir a incubação longa com CaCO3. Além disso, a estimativa da acidez potencial utilizando a equação do CQFS-RS/SC (2016) superestimou a acidez potencial de solos com valores de pH em solução TSM inferiores a 6,0 neste estudo.

ABSTRACT: Potential soil acidity can be measured by two methods in the states of Rio Grande do Sul (RS) and Santa Catarina (SC): solution SMP or solution TSM (Buffer Santa Maria). Calibration of these methods is done by incubating soils for long periods (180 days) of CaCO3. The hypothesis of this study is that it is possible to reduce the incubation period in soils by using a soluble base such as calcium hydroxide. The study aimed to estimate potential acidity in a group of soils by moist incubation with Ca(OH)2 (short) as an alternative to the typical method with CaCO3 (long) and relate to the values estimated by the equation used by the Soil Chemistry and Fertility Commission of Rio Grande do Sul and Santa Catarina (CQFS-RS/SC; 2016). Ten soils with sandy texture and low organic matter content were collected at 0-20cm in the Campanha Gaúcha region of the state of RS and incubated for 180 days with doses of CaCO3 equivalent to 0, 25, 50, 75, 100, 125 and 150% of the lime requirement estimated by the solution TSM to raise to pH 6.0. Soils were also incubated for 4 days in an oven at 35ºC with 0.22mol L-1 Ca(OH)2 at doses equivalent to CaCO3. Short incubation of the soil with Ca(OH)2 may substitute long incubation with CaCO3. Also, estimating potential acidity using the equation of the CQFS-RS/SC (2016) overestimated potential acidity in soils with solution TSM pH values lower than 6.0 in this study.

ABSTRACT Sandy soils of the Campanha Gaúcha region have naturally low levels of available phosphorus (P), which is why special attention to pre-planting fertilization is important. However, there are no studies that enable a proper calibration method to determine P content available in soil for young grapevines. The study aimed to evaluate phosphorus fertilization for young grapevines of Chardonnay and Pinot Noir in order to provide support for the recommendation of P in sandy soils. In October, 2011 we applied six doses of P (0, 10, 20, 40, 60 and 100 kg P2O5 ha-1 yr-1) in soil and transplanted cultivars of Chardonnay (experiment 1) and Pinot Noir (ex-periment 2). The design of each experiment was randomized blocks with ten plants and three replications. We evaluated P content in the soil and leaves. We determined plant height, stem diameter and dry matter of the pruned material from crop seasons 2011/12 to 2014/15. The addition of increasing P doses elevated P content available in soil three years after implementing the experiments, but exclusively in doses above 40 and 60 kg P2O5 ha-1 in Pinot Noir and Chardonnay, respectively. However, P content in soil for every applied P dose remained below sufficiency level, and therefore growth parameters and leaf P content were virtually unaffected.

RESUMEN Los suelos arenosos de la región Campanha Gaúcha son naturalmente bajos en contenidos de fósforo (P) disponible, por lo que requiere una atención especial con la fertilización previo a la siembra. Sin embargo, aún no existen trabajos de investigación que permitan una calibración adecuada para determinar el contenido de P disponible en suelos para el cultivo de vides viníferas jóvenes. El objetivo de esta investigación fue evaluar la fertilización fosfatada en las variedades jóvenes de vid Chardonnay y Pinot Noir a fin de sugerir dosis a la recomendación de P, en suelos arenosos. En Octubre de 2011 fueron aplicadas seis dosis de P (0, 10, 20, 40, 60 y 100 kg P2O5 ha-1 año-1) en suelo y transplantadas las variedades Chardonnay (experimento 1) y Pinot Noir (experimento 2). El diseño experimental fue de bloques completos al azar, con tres repeticiones, y diez plantas. Fueron evaluados los contenidos de P en el suelo, en hojas, altura de plantas, diámetro del tallo y materia seca del material podado durante las cosechas del 2011/12 a 2014/15. La adición de dosis crecientes de P incrementó el contenido de P disponible en el suelo después de los tres años del establecimiento de los experimentos cuando las dosis fueron superiores de 40 y 60 de P2O5 ha-1 en las variedades Pinot Noir y Chardonnay, respectivamente. En todos los estados los contenidos en P en suelo, fueron suficientes, por lo tanto, el crecimiento y contenido de P en las Hojas, no fueron afectadas.

ABSTRACT Crotalaria juncea is used as plant cover in grape vineyards in Brazil, which usually present soils with high copper (Cu) levels due to the application of Cu-based phyto-sanitary products. Under this condition an increase growth and cover of C. juncea is needed to improve the phytoremediation processes in those soils. Some alternatives to achieve this condition is the inoculation with arbuscular mycorrhizal fungi (AMF), which has demonstrated an important increase of plant growth in Cu-contaminated soils at different soil P levels. The aims of this study were to evaluate the effect of AMF inoculation in soils with high Cu contents on the growth of C. juncea, the acid phosphatase (APase) enzyme activity in plants and soil, and the presence of glomalin under different P supply conditions, as a basis to identify if there is a synergistic interaction between AMF inoculation and P supply on soils with high Cu levels. The experiment was carried under greenhouse conditions in a factorial 3 × 2 design (natural P content, addition of 40 and 100 mg kg-1 P, with and without the inoculation of the AMF Rhizophagus clarus with three replicates) in a soil with high Cu content (60 mg kg-1). The addition of 40 and 100 mg kg-1 P favored plant growth both in the presence and in the absence of AMF. However, when plants were grown in soil with a natural P level, the inoculation with AMF increased by 116 % the shoot biomass, compared to the non-inoculated treatment. Our results showed that the combination of P supply and R. clarus inoculation could be an adequate strategy to reduce Cu phytotoxicity in C. juncea, as it increases plant biomass and modify the APase enzyme activity in the soil and plant. Additionally, glomalin produced by the AMF and accumulated in the soil can decrease the availability of Cu to the plants by means of sequestration beyond the root surface, with a consequent plant protective effect.

Resumo: O objetivo deste trabalho foi avaliar o efeito das aplicações de dejetos líquidos de suínos no teor de Al trocável, na atividade e na distribuição das espécies químicas de Al na solução do solo. Amostras de um Argissolo foram obtidas de um experimento conduzido durante oito anos, com 19 aplicações de 0, 20, 40 e 80 m3 ha-1 de dejetos líquidos de suínos. As amostras de solo foram coletadas em camadas, para determinação do Al trocável e extração da solução do solo pelo método da pasta de saturação. Na solução, foram determinados as concentrações dos principais cátions e ânions, o carbono orgânico dissolvido e o pH. A distribuição das espécies químicas de Al e a atividade da espécie Al3+ foram obtidas pelo programa Visual Minteq. A aplicação de dejetos líquidos de suínos não altera o teor de Al trocável no solo e a atividade de Al3+ na solução do solo. A baixa atividade de Al3+ nas camadas superficiais não apresenta risco de toxidez para a maioria das culturas. A adição de dejetos líquidos de suínos aumenta a proporção das espécies AlHPO4 + e AlSO4 + na solução do solo, por incrementar a concentração de ligantes inorgânicos solúveis.

Abstract: The objective of this work was to evaluate the effect of pig slurry applications on the exchangeable Al content, activity, and distribution of Al chemical species in the soil solution. Soil samples of a Typic Hapludalf were obtained from an experiment conducted during eight years, with 19 applications of 0, 20, 40, and 80 m3 ha-1 pig slurry. The soil samples were collected in stratified layers to determine exchangeable Al content and to extract the soil solution by the saturated soil paste method. The concentrations of the main cations and anions, dissolved organic carbon, and pH in the soil solution were determined. The distribution of the chemical species of Al and the activity of the Al3+ species were obtained through the Visual Minteq software. The application of pig slurry does not change the exchangeable Al content in the soil and the Al3+ activity in the soil solution. The low Al3+ activity in the topsoil layers does not present risk of toxicity for most crops. Pig slurry applications increase the proportion of the AlHPO4 + and AlSO4 + species in the soil solution, by increasing the concentration of soluble inorganic ligands.

The presence of cover crops in vineyards may decrease the availability of nitrogen (N) derived from fertilizer to grapevines. The present study aimed to evaluate the recovery of urea-15N and growth of young grapevines with and without natural vegetation in plant rows. The study was conducted in southern Brazil on one-year-old Chardonnay grapevines grown in soils with and without cover crops. The grapevines were subjected to the application of 40 kg N ha-1 in the form of urea-15N at 3% 15N atom excess. Dry matter yield, total N and fertilizer N were assessed in grapevines and soil layers. A small amount of N that is applied during the growing season of the grapevines is readily assimilated by the plants. The maintenance of cover crops in young vineyards may favor the maintenance of higher levels of N in the subsurface layers of the soil, contributing to the nutrition of the grapevines in the following growth cycles. The presence of cover crops reduced the importance of nitrogen fertilization in the growth cycle of grapevines because a large part of N absorbed by grapevines was derived from other sources. Nitrogen derived from the fertilizer applied to the soil in the presence or absence of cover crops was mainly concentrated in the newly-formed vegetative grapevine organs (leaves and shoots).

RESUMO Adubação nitrogenada em videiras em crescimento é um tema ainda muito carente de informações, especialmente em cultivos em solos arenosos do Bioma Pampa, no Rio Grande do Sul, onde a viticultura expandiu-se consideravelmente na última década. Este estudo objetivou avaliar o impacto de doses de N no crescimento de plantas jovens de videiras ‘Chardonnay’ e ‘Pinot Noir’ e nas formas de N presentes em solo arenoso do Bioma Pampa. O experimento foi realizado de outubro de 2011 a dezembro de 2012, em vinhedo de Santana do Livramento, no extremo Sul do RS, em solo com teor de argila de 82 g kg-1, na camada de 0-20 cm. Videiras das variedades ‘Chardonnay’ e ‘Pinot Noir’ foram submetidas à aplicação de 0, 10, 20, 40, 60 e 80 kg de N ha-1 ano-1. Durante dois ciclos de crescimento e em três épocas, foram avaliados teores de N de folhas, leituras SPAD, diâmetro de caule, altura de plantas e matéria seca do material podado. Foram coletadas amostras nas camadas de 0-10 e 10-20 cm, em quatro épocas, durante os cultivos, nas quais foram determinados os teores de N-NH4 +, N-NO3 -, N total e calculado o N mineral. As doses de N aplicadas em videiras jovens, embora não tenham proporcionado alterações relevantes dos teores de N-NH4 +, N-NO3 - e N mineral no solo, foram capazes de incrementar o teor de N das folhas, aumentando o vigor das plantas. Isso porque houve incremento de diâmetro de caules, de altura das plantas e de matéria seca do material da poda, na maioria das épocas de avaliação. Estes parâmetros sugerem melhores padrões de crescimento e de uniformidade de plantas de videiras jovens, com possíveis efeitos positivos na antecipação da produção, mostrando a importância de estratégias de adubação nitrogenada para as videiras em crescimento, nas condições de solo arenoso do Bioma Pampa.

ABSTRACT Information on nitrogen fertilization in growing vines is still a very limited subject, especially for crops on sandy soils in the Pampa Biome in Rio Grande do Sul, where viticulture has expanded considerably in the last decade. This study aimed to assess the impact of N doses on growth of young plants of Chardonnay and Pinot Noir vines and N forms present in sandy soil in the Pampa Biome. The experiment was conducted from October 2011 to December 2012 in a vineyard in Santana do Livramento, in Southern Rio Grande do Sul State, in soil with 82 g kg-1 clay in the 0-20 cm layer. Vines of Chardonnay and Pinot Noir varieties were subjected to applications of 0, 10, 20, 40, 60, and 80 kg N ha-1 year-1. Total N in leaves, SPAD readings, stem diameter, plant height, and dry matter of the pruned material were evaluated in two growth cycles and three times. Soil samples were collected at 0-10 and 10-20 cm depths at four crop growth stages, in which N-NH4 +, N-NO3 -, and total N were analyzed and the mineral N was calculated. The N levels applied to young vines, although they did not provide relevant changes in the N-NH4 +, N-NO3 -, and mineral N contents in the soil, were able to increase the N content in the leaves, increasing plant vigor. because the reason is that there was an increase in stem diameter, plant height, and dry matter of pruned material in most evaluation periods. These parameters suggest better growth patterns and uniformity of young grapevines with possible positive effects in anticipation of production, demonstrating the importance of nitrogen fertilization strategies to the growing vines in the sandy soil conditions of the Pampa Biome.

ABSTRACT Applications for long periods of organic animal waste as a source of nutrients to crops can contaminate the soil and the surface and subsurface waters. This study aimed to evaluate how the utilization of organic waste, after successive applications, affects P fractions in the soil and consequently environmental contamination. In an experiment conducted for 8 years, totaling 12 applications with pig slurry manure (PSM), liquid cattle manure (LCM), swine deep bedding (SDB), and mineral fertilizer (NPK), 460; 505; 1.111; and 535 kg P∙ha−1 were added to the soil through PSM, LCM, SDB, and NPK, respectively. In September 2012, soil samples were collected in the layers 0.0 – 0.04; 0.04 – 0.08; 0.08 – 0.12; 0.12 – 0.16; 0.16 – 0.20 m, prepared and subjected to a sequential chemical fractionation of P. The 12 applications of pig slurry, liquid cattle manure, swine deep bedding and NPK fertilizer for eight years (urea + triple superphosphate + potassium chloride) provided accumulations of P fractions in the soil that were above the necessary for a proper nutrition to plants considering the available P fractions (AER + organic NaHCO3 + inorganic NaHCO3) in the soil. In addition, they showed that the use of swine deep bedding, followed by pig slurry, means higher levels of available P fractions in the soil. In this sense, the establishment of a dosage of organic waste to meet the nitrogen need of crops is not an environmentally appropriate parameter. It may cause P accumulation in the soil, increased absorption ability of plants and soil support, contributing to environmental contamination.

RESUMO: O impacto da adubação nitrogenada na produção e composição de frutos em pomares de laranjeiras cultivados em solos com baixo ou médio teor de matéria orgânica do RS é pouco conhecido. Este trabalho objetivou avaliar como a adubação nitrogenada, em solo de textura arenosa, pode interferir na produção, composição de frutos e do suco em laranjeiras cv. 'Lane Late'. O experimento foi conduzido em um pomar de laranjeiras cv. 'Lane Late' instalado sobre um Argissolo Vermelho, em Rosário do Sul (RS). As plantas foram submetidas à aplicação de 0, 20, 40, 60, 80, 100, 120, 140 e 160 kg ha-1 de N. Nas safras de 2010/2011 e 2011/2012 foi avaliado o teor total de N em folhas, o número de frutos por planta, a produção, o peso fresco e diâmetro de frutos, espessura da casca, porcentagem de suco nos frutos, cor da epiderme e do suco, os valores de vitamina C, sólidos solúveis totais (SST) e acidez total titulável. Na primeira safra, especialmente a produção, o número de frutos por planta, o teor de SST no suco e o ratio diminuíram com o aumento da dose de N aplicada. Mas, na segunda safra, de forma destacada, o teor de acidez total titulável no suco aumentou com a dose de N aplicada. Nas duas safras, os resultados foram muito influenciados pela distribuição das precipitações pluviométricas, que afetam a fisiologia da planta, a dinâmica do N no solo e, por consequência, a probabilidade de resposta ao N aplicado, bem como as perdas de N mineral no solo.

ABSTRACT: 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.

RESUMO A aplicação de fungicidas foliares em vinhedos e pomares pode incrementar os teores de metais pesados, como o cobre (Cu) e o zinco (Zn), em solos e, quando em excesso, podem causar toxidez às frutíferas ou plantas de cobertura. Porém, algumas práticas agronômicas, como a calagem, adição de resíduos orgânicos, cultivo de plantas de cobertura do solo e inoculação de plantas jovens com fungos micorrízicos arbusculares (FMA) podem diminuir a disponibilidade e o potencial de toxidez de metais pesados às frutíferas. A presente revisão objetivou compilar e apresentar informações sobre os efeitos do aumento dos teores de metais pesados, especialmente, Cu e Zn, em solos cultivados com frutíferas e algumas práticas agronômicas de remediação. Ao longo do texto são apresentadas informações sobre as fontes de metais pesados, com enfase no Cu e Zn, em solos cultivados com frutíferas; mecanismos de absorção, transporte, acúmulo e potencial de toxidez às plantas. Além disso, são relatadas algumas práticas agronômicas viáveis para remediar o potencial de toxidez de metais pesados em solos cultivados com frutíferas. Com a adoção destas práticas se espera menor disponibilidade de metais pesados no solo, o que reduziria o potencial de toxidez às plantas, especialmente, em frutíferas jovens transplantadas em solos com alto teor de metais pesados, como o Cu e Zn, permitindo satisfatório crescimento, produção e composição de frutos.

ABSTRACT The application of foliar fungicides in vineyards and orchards can increase soil concentration of heavy metals such as copper (Cu) and zinc (Zn), up to the toxicity threshold for fruit trees and cover crops. However, some agronomic practices, such as liming, addition of organic fertilizers, cultivation of soil cover crops and inoculation of young plants with arbuscular mycorrhizal fungi can decrease the availability and the potential of heavy metal toxicity to fruit trees. This review aims to compile and present information about the effects of increasing concentrations of heavy metals, especially Cu and Zn, on soils cultivated with fruit trees and provides some agronomic practices of remediation. Information about the sources of heavy metals found in soils cultivated with fruit trees are presented; mechanisms of absorption, transport, accumulation and potential toxicity to plants are described.

ABSTRACT In Southern Brazil, agricultural soils are often treated over long periods with annual pig slurry (PS) applications, and their influence on soil nutrient dynamics should be monitored. This study aimed to evaluate the P forms accumulated in the soil and some biological and biochemical parameters of the P cycle after 19 successive PS applications over eight years, in a no-tillage (NT) system. Pig slurry was applied at rates of 0, 20, 40, and 80 m3 ha-1 per crop. Several P forms (available P, microbial P, phosphatase enzyme, total organic and inorganic P) in the 0.00-0.05 and 0.05-0.10 m soil layers were analyzed. Increases up to 5,523 % in available P, 308 % in microbial P, 104 % in phosphatase enzyme activity, 91 % in organic P, 251 % in inorganic P, and 19 % in Total-P were observed in the 0.00-0.05 m soil layer in response to the highest PS rate compared to the treatment with no PS. Results also indicated that P added via PS was preferentially accumulated in the inorganic fractions (83-98 %). The increase in organic P was limited by the increase in soil organic carbon. The increase in soil microbial biomass-P was more influenced by available P, while the increase in phosphatase enzyme activity was more related to the increase in organic P and C. Therefore, PS applied to the soil affected the chemical, biological, and biochemical components of the soil P cycle. Results indicate that even half of the PS rate normally used by farmers (20 m3 ha-1) poses a high risk of pollution of water bodies by runoff from these soils.

RESUMO: O potássio (K) é um dos macronutrientes exigidos em maior quantidade pela videira, porém o seu incremento no solo pode não aumentar a produção de uva, mas pode modificar a sua composição. O trabalho objetivou avaliar a interferência do teor de K trocável no solo sobre o seu teor na folha, produção e composição do mosto da cv. 'Cabernet Sauvignon'. Em setembro de 2011, em Santana do Livramento (RS), foram selecionados cinco vinhedos com níveis crescentes de K trocável no solo. Nas safras 2012/13 e 2013/14, foi avaliada a produção de uva, os componentes de produção, o teor total de K nas folhas no pleno florescimento e na mudança da cor das bagas. No mosto, foram avaliados os valores de sólidos solúveis totais (SST), pH, a acidez total titulável (ATT) e os totais de polifenóis e antocianinas. O incremento do teor de K trocável no solo aumentou o K total nas folhas no pleno florescimento, nas bagas e a composição do mosto, mas não afetou a produção de uva da cv. 'Cabernet Sauvignon'.

ABSTRACT: Content of exchangeable potassium (K) in t soil may influence on its content in grapevines leaves, grape yield, as well as, in must composition. The study aimed to assess the interference of exchangeable K content in the soil on its leaf content, production and must composition of 'Cabernet Sauvignon' cultivar. In September 2011, in Santana do Livramento (RS) five vineyards with increasing levels of exchangeable K in the soil were selected. In the 2012/13 and 2013/14 harvests, the grape yield, yield components, total K content in the leaves in full bloom and berries veraison were evaluated. Values of total soluble sugar (TSS), pH, total titratable acidity (TTA), total polyphenols and anthocyanins were evaluated in the must. Exchangeable K content increase in soil with sandy surface texture increased its content in leaves collected during full flowering and in berries and must pH; however, it did not affect production of the 'Cabernet Sauvignon'.