Calagem como forma de redução da toxidez por cobre em aveia preta

Soils which are cultivated with grapevines have high available copper (Cu) content, which can be toxic to cover crops cohabiting vineyards, such as black oats. This study aimed to assess the effect of liming in reducing Cu toxicity in black oats grown in sandy soils. Samples of a Typic Hapludalf were collected at 0-20cm, dried and subjected to the addition of Cu (0 to 50Mg kg-1) and limestone (0, 1.5, and 3.0Mg ha-1). The soil was placed in a rhizobox and black oats were grown for 30 days. We assessed root and shoot dry matter production, copper (Cu), calcium (Ca) and magnesium (Mg) contents in the tissues; Cu content in the root symplast and apoplast, as well as Cu, carbon and pH values in the rhizosphere and bulk soil. Liming reduced Cu toxicity in black oats. Cu was preferentially accumulated in the roots, mostly in the apoplast, which may be the result of a plant tolerance mechanism to prevent the transport of Cu to the shoots. Key words: heavy metal, phytotoxicity, limestone, rhizosphere.Solos cultivados com videiras possuem alto teor de cobre (Cu) disponível, que pode ser tóxico às plantas de cobertura do solo que coabitam vinhedos, como a aveia preta. O estudo objetivou avaliar o efeito da calagem na redução da toxidez por Cu em plantas de aveia preta cultivadas em solo arenoso. Amostras de um Argissolo Vermelho foram coletadas na camada de 0-20cm, secas e submetidas à adição de duas doses de Cu (0 e 50Mg kg-1) e três de calcário (0, 1,5 e 3,0Mg ha-1). O solo foi acondicionado em rhizobox e submetido ao cultivo de aveia preta durante 30 dias. Avaliaram-se a produção de matéria seca das raízes e da parte aérea, o teor de cobre (Cu), cálcio (Ca) e magnésio (Mg) nos tecidos; o teor de Cu no simplasto e apoplasto das raízes, e os teores de Cu, de carbono e valores de pH no solo rizosférico e não rizosférico. A aplicação de calcário reduziu a toxidez por Cu na aveia preta. O Cu foi preferencialmente acumulado nas raízes, especialmente no apoplasto, o que pode ser resultado de mecanismo de tolerância das plantas para evitar o transporte de parte do elemento para a parte aérea

Produtividade de uvas e composição do mosto de videiras ‘Cabernet Sauvignon’ fertilizadas com composto orgânico e ureia

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.A ureia e o composto orgânico são aplicados em vinhedos como fonte de nitrogênio (N). O estudo objetivou avaliar a produtividade, o teor de N total em folhas e a composição do mosto em videiras submetidas à aplicação de composto orgânico e ureia. Videiras ‘Cabernet Sauvignon’ nas safras de 2008/2009 e 2009/2010 foram submetidas à aplicação de 40 kg de N ha-1 na forma de composto orgânico e ureia, mas videiras também não foram adubadas. Nas duas safras foram coletadas folhas no florescimento e na mudança da cor das bagas, preparadas e submetidas à análise de N total. A produção de uva foi avaliada e atributos enológicos foram determinados no mosto. A aplicação de composto orgânico e ureia não afetou o teor de N total nas folhas e a produção de uva na segunda safra avaliada. Mas, na primeira safra, a produção de uva foi maior nas videiras submetidas à aplicação com composto orgânico no solo. A adição de fontes de N não afetou o conteúdo de nutrientes no mosto mas, na segunda safra, o mosto da uva derivado das plantas com a adição de composto orgânico apresentou baixo teor de sólidos solúveis totais, maior valor de acidez, ácido tartárico e ácido málico

Nitrogen supply method affects growth, yield and must composition of young grape vines (Vitis vinifera L. cv Alicante Bouschet) in southern Brazil.

The aim of this study was to evaluate yield and chemical composition of the must in grapevines subjected to Nitrogen (N) supply methods in sandy soils. The vineyard cultivar was ?Alicante Bouschet? (Vitis vinifera L.) grafted on 1103 Paulsen rootstock, in southern Brazil. The treatments consisted of the application of 20+20 kg N ha−1 without irrigation (NWI), 20+20 kg N ha−1 followed by irrigation (NFI), 20+20 kg N ha−1 via fertigation (NF), 20 kg N ha−1 via fertigation (½NF), and a control (C) without N application. The study was conducted during four crop seasons. Leaves were collected at flowering and veraison to determination N concentration. Stem diameter, grape yield and its components were determined. In the must were evaluated the total soluble solids (TSS), pH, total titratable acidity (TTA) and total anthocyanins (TA). The concentration of nitrate and ammonium in soil solution was determined. N application followed by irrigation or N supplied via fertigation provided to the vines larger stem diameters and leaf N concentrations, in most crop seasons. Grapevines submitted to N application via fertigation or followed by irrigation presented higher yields than conventional application without irrigation, and between two and three times higher than the control. N supply methods little affected total soluble solids contents. The application of N to the soil, regardless of the N supply method, decreased the anthocyanin concentration in the grape must, due to the dilution effect on the pulp/skin ratio, promoted by the yield increase

THE ROLE OF MINERAL NUTRITION ON YIELDS AND FRUIT QUALITY IN GRAPEVINE, PEAR AND APPLE

ABSTRACT Fertilization of temperate fruit trees, such as grapevine ( Vitis spp.), apple ( Malus domestica), and pear ( Pyrus communis) is an important tool to achive maximum yield and fruit quality. Fertilizers are provided when soil fertility does not allow trees to express their genetic potential, and time and rate of application should be scheduled to promote fruit quality. Grapevine berries, must and wine quality are affected principally by N, that regulate the synthesis of some important compounds, such as anthocyanins, which are responsible for coloring of the must and the wine. Fermenation of the must may stop in grapes with low concentration of N because N is requested in high amount by yeasts. An N excess may increase the pulp to peel ratio, diluting the concentration of anthocyanins and promoting the migration of anthocyanins from berries to the growing plant organs; a decrease of grape juice soluble solid concentration is also expected because of an increase in vegetative growth. Potassium is also important for wine quality contributing to adequate berry maturation, concentration of sugars, synthesis of phenols and the regulation of pH and acidity. In apple and pear, Ca and K are important for fruit quality and storage. Potassium is the most important component of fruit, however, any excess should be avoided and an adequate K:Ca balance should be achieved. Adequate concentration of Ca in the fruit prevents pre- and post-harvest fruit disorders and, at the same time, increases tolerance to pathogens. Although N promotes adequate growth soil N availability should be monitored to avoid excessive N uptake that may decrease fruit skin color and storability

Flowering induction time of 'pérola' pineapple cultivated in rain forest area of Roraima, Brazil

Com o objetivo de obter subsídios para ampliação das épocas de produção do abacaxizeiro (Ananas comosus (L.) Merrill), cv. 'Pérola', cultivado em área de mata de terra firme de Roraima, conduziu-se experimento em solo Podzólico Vermelho-Amarelo (PV), em delineamento experimental de blocos ao acaso, com cinco tratamentos, quatro subamostragens e quatro repetições. Os tratamentos constaram de indução da diferenciação floral, com acetileno, aos 6, 8, 10, 11 e 12 meses de idade. O número de filhotes/planta e o peso do fruto com e sem coroa tenderam a aumentar com a idade da planta e os tratamentos não influíram no teor de sólidos solúveis totais (brix).The objective of this research was to obtain subsidies to increase the production period of pineapple (Ananas comosus (L.) Merrill) cv. 'Pérola' cultivated in rain forest area of Roraima, Brazil. The experiment was conducted in red-yellow podzolic soil, in completely randomized blocks with five treatments, four subsamples and four repetitions. The treatments studied were flowering induction, with acetylene, at 6, 8, 10, 11 and 12 months after planting. By the results obtained, the number of suckers/plant and the fruit weight tended to increase when the plants were induced later and the treatments did not have effect on the brix contents

Potassium-bearing minerals in two oxisols of Rio Grande do Sul State, Brazil

Este estudo teve como objetivo identificar os minerais fonte de K em dois solos originários de basalto: um Latossolo Vermelho distroférrico típico e um Nitossolo Vermelho distroférrico típico. A análise mineralógica por difratometria de raios-X mostrou a provável presença de um mineral micáceo nas frações silte fino e argila grossa do Latossolo e nas frações silte grosso, silte fino e argila grossa do Nitossolo. Em ambos os solos, também se observou a presença de feldspatos na areia e silte, bem como de esmectita com material hidróxi nas entrecamadas (2:1 EHE) nas frações argila grossa e fina, acompanhando a caulinita dominante. A fração argila grossa dos solos apresentou maiores evidências da presença de minerais potássicos, constituindo a fração com maior potencial para suprir K às plantas.The objective of this study was to identify the K-bearing minerals as well as the granulometric fraction of the soil with potential to supply K to the plants from two basaltic Oxisols (Hapludox and Kandiudox). The mineralogical analyses of the granulometric fractions of the Hapludox soil revealed the probable occurrence of a mica mineral in the fine silt and coarse clay fractions, while feldspar minerals occurred in the sand, coarse silt, and fine silt fractions. In the Kandiudox soil, a probable mica mineral was observed in the coarse silt, fine silt, and coarse clay fractions, whereas feldspar minerals were observed in the sand and silt fractions. In both soils, the presence of a 2:1 clay mineral with hydroxy interlayer material (2:1 EHI) was also observed. This clay mineral has the basic structure of a smectite mineral. The coarse clay fraction of both soils presented the strongest evidences of the presence of K-bearing minerals, representing the most promising fraction for K supply to plants

Potassium-bearing minerals in two oxisols of Rio Grande do Sul State, Brazil

Este estudo teve como objetivo identificar os minerais fonte de K em dois solos originários de basalto: um Latossolo Vermelho distroférrico típico e um Nitossolo Vermelho distroférrico típico. A análise mineralógica por difratometria de raios-X mostrou a provável presença de um mineral micáceo nas frações silte fino e argila grossa do Latossolo e nas frações silte grosso, silte fino e argila grossa do Nitossolo. Em ambos os solos, também se observou a presença de feldspatos na areia e silte, bem como de esmectita com material hidróxi nas entrecamadas (2:1 EHE) nas frações argila grossa e fina, acompanhando a caulinita dominante. A fração argila grossa dos solos apresentou maiores evidências da presença de minerais potássicos, constituindo a fração com maior potencial para suprir K às plantas.The objective of this study was to identify the K-bearing minerals as well as the granulometric fraction of the soil with potential to supply K to the plants from two basaltic Oxisols (Hapludox and Kandiudox). The mineralogical analyses of the granulometric fractions of the Hapludox soil revealed the probable occurrence of a mica mineral in the fine silt and coarse clay fractions, while feldspar minerals occurred in the sand, coarse silt, and fine silt fractions. In the Kandiudox soil, a probable mica mineral was observed in the coarse silt, fine silt, and coarse clay fractions, whereas feldspar minerals were observed in the sand and silt fractions. In both soils, the presence of a 2:1 clay mineral with hydroxy interlayer material (2:1 EHI) was also observed. This clay mineral has the basic structure of a smectite mineral. The coarse clay fraction of both soils presented the strongest evidences of the presence of K-bearing minerals, representing the most promising fraction for K supply to plants