ABSTRACT Copper (Cu)-contaminated soils are becoming more common, and phytoremediation is an effective strategy for reducing the negative effects of Cu on soils. Tree species are commonly used for this technique because they act as a barrier to this type of contamination. It is necessary to evaluate Cu tolerance and toxicity thresholds together with the harm this metal causes to plants. The objective of the current study was to investigate the tolerance of Handroanthus heptaphyllus plants to Cu through morpho-physiological, biochemical, and tissue Cu concentration analyses. H. heptaphyllus seedlings were subjected to nutrient solutions with varying concentrations of copper: 0, 5, 32, 64, 96, and 128 µM Cu in a hydroponic system. We conducted a morpho-physiological trait analysis on shoot height, root length, dry weight, morphological variables of the root system, leaf area, and photosynthetic variables. In addition, we also looked into photosynthetic pigments, antioxidant enzymes, lipid peroxidation, hydrogen peroxide concentration, and Cu accumulation in tissues. The values obtained for variables such as dry weight and pigments did not show significant differences, regardless of Cu concentration. Moreover, photosynthetic and transpiration rates were negatively affected only at the highest Cu concentration (128 µM). Overall, excess Cu had no effect on Handroanthus heptaphyllus below 128 µM. Cu accumulated mainly in the roots without a decrease in biomass, which could indicate the tolerance of the species to this metal as well as its great potential in the phytostabilization of Cu in contaminated soils.

RESUMO Solos contaminados com cobre (Cu) são um problema crescente, e o uso da fitorremediação tem evidenciado resultados positivos na redução dos efeitos nocivos desse elemento nos solos. Espécies arbóreas têm sido amplamente utilizadas para esta técnica, pois funcionam como barreira a esse tipo de contaminação. Portanto, é necessário avaliar os limites de tolerância/toxicidade ao Cu, bem como os danos causados por este metal nas plantas. Assim, o presente estudo teve como objetivo investigar a tolerância de plantas de Handroanthus heptaphyllus ao Cu através de análises morfofisiológicas e bioquímicas, bem como a concentração de Cu nos tecidos. Mudas de H. heptaphyllus foram submetidas a diferentes concentrações de Cu adicionadas na solução nutritiva: 0,5, 32, 64, 96 e 128 μM Cu em sistema hidropônico. Foram analisados atributos morfofisiológicos, como altura da parte aérea e comprimento da raiz, massa seca, variáveis morfológicas do sistema radicular, área foliar e variáveis fotossintéticas. Além disso, foram investigados pigmentos fotossintéticos, enzimas antioxidantes, peroxidação lipídica, concentração de peróxido de hidrogênio e Cu acumulado nos tecidos. Os valores registrados para variáveis como massa seca e pigmentos não apresentaram diferença significativa, independentemente das concentrações de Cu. Além disso, as taxas fotossintéticas e transpiratórias foram afetadas negativamente apenas na maior concentração de Cu (128 μM). No geral, a espécie Handroanthus heptaphyllus foi afetada pelo excesso de Cu apenas em 128 μM. O Cu se acumulou principalmente nas raízes, sem registrar diminuição da biomassa, o que pode indicar a tolerância da espécie a esse metal, bem como seu grande potencial para ser utilizado na fitoestabilização de Cu em solos contaminados com este metal.

RESUMO: O estudo quantificou os parâmetros cinéticos de captação de K nas gramíneas Paspalum notatum, Paspalum urvillei e Axonopus affinis associados com o crescimento. Dez mililitros (10 ml) de solução nutritiva foram coletados em vasos de dois litros - com cinco repetições em 24 horas - para determinação das concentrações de K nas amostras. A matéria seca da parte aérea e raízes; comprimento, volume, diâmetro e área superficial radicular, bem como parâmetros cinéticos associados à absorção de nutrientes (Vmax, Km, Cmin e I) foram avaliados. A espécie P. notatum apresentou a maior produção de raiz, parte aérea e MS total, bem como o maior volume de raiz. P. urvillei apresentou o maior teor de K, que pode ser associado a raízes mais finas e resultando em maior área superficial. A. affinis registrou o maior valor de Vmax, o que levou a uma maior eficiência de absorção de K.

ABSTRACT: This study quantified K uptake kinetic parameters in grass species Paspalum notatum, Paspalum urvillei and Axonopus affinis to associate them with growth. Ten milliliters (10 ml) of nutrient solution were collected in two-liter pots - with five repetitions in 24 hours - in order to determine K concentrations in the samples. Shoot and root dry matter, root length, volume, diameter and surface area, as well as kinetic parameters associated with nutrient uptake (Vmax, Km, Cmin and I) were determined. Species P. notatum was the one presenting the highest root, shoot and total dry matter production, as well as the highest root volume. P. urvillei recorded the highest K content, which may be associated with thinner roots and greater root surface area. A. affinis recorded the highest Vmax value, which led to greater K uptake efficiency.

ABSTRACT The aim of this study was to evaluate the effect of new Ca sources sprayed on ‘Fuji Suprema’ and ‘Maxi Gala’ apple trees on nutrient levels in leaves and fruit, as well as on fruit ripening features and quality at harvest time and after cold storage. Experiments were carried out in a commercial orchard planted with ‘Fuji Suprema’ and ‘Maxi Gala’ apple trees in Caçador, Santa Catarina state, Brazil. Application of different Ca sources and untreated trees were evaluated in each experiment. Fruit were harvested at two different ripening stages and analyzed based on the following variables: fruit ripening at harvest time, as well as fruit quality and incidence of physiological disorders after 210-day storage at 1 °C. Calcium applications did not change Ca levels in the leaves and of the whole fruit. Calcium levels in fruit peel increased in cultivars Maxi Gala and Fuji Suprema due to leaf Ca applications. ‘Maxi Gala’ apples recorded higher postharvest incidence of physiological disorders, such as greater loss of fruit firmness than ‘Fuji Suprema’ apples (Due to 1-methylcyclopropene [1-MCP] application on ‘Fuji Suprema’ apples). Calcium applications did not change fruit maturation (starch index and pulp firmness) or apple pulp firmness preservation in both cultivars, although they reduced the incidence of bitter pit disorder in ‘Maxi Gala’ apples. The new sources of Ca tested did not increase Ca contents, nor did they reduced the risk for physiological disorder compared to the standard CaCl2 treatment that has been commercially used for decades as the main Ca fertilizer.

ABSTRACT Soils with low potassium (K) availability require corrective fertilization for grain crops. The recommended rate to increase K availability up to the critical level depends on the soil K buffering capacity (KBC). This study aimed to quantify the KBC and recalculate the rates necessary to reach the K critical level in 23 soils from Southern Brazil. Soil samples were incubated with six K rates, that were thus grouped according to CECpH7.0: below 7.5 cmolc dm-3 (0, 30, 60, 90, 120 and 180 kg K2O ha-1); from 7.6 to 15 cmolc dm-3 (0, 30, 60, 120, 180 and 240 kg K2O ha-1) and from 15.1 to 30 cmolc dm-3 (0, 30, 60, 120, 240 and 360 kg K2O ha-1). The soil test K (STK) was extracted by Mehlich-1 and the fertilizer rates necessary to increase the STK by 1 mg dm-3 were quantified. The KBC values were correlated with a suite of soil testing metrics. The relationship between the cation exchange capacity (CECpH7.0) and KBC was modeled, and a linear-plateau equation presented the best fit. The K rates were calculated using the following equation: K rate = ( Critical Level − S T K ) × K B C and were compared with the current rate indicated by the Local Soil Fertility Committee. The K fertilizer rates by KBC were about 2.5 times higher than the values currently indicated, and the largest differences were observed in soils with low STK and high CECpH7.0.

ABSTRACT Bases are chemical species that donate electrons, accept protons, or release hydroxyls (OH–) in aqueous solution. In Soil Science, “base saturation”, “exchangeable bases” or “basic cations” has been widely used to distinguish Ca2+, Mg2+, Na+, and K+ from H+ and Al3+ cations. This terminology is confusing since none of these cations are truly a base in chemistry sense. However, in the absence of the proposition of a correct term, the term “base saturation” remains in use nowadays, causing confusion among students, professionals, and even among professors and researchers in Soil Science, as it leads to the erroneous interpretation that the soil acidity can be corrected by adding these cations to the soil. Here, we present the historical background of this nomenclature and a theoretical foundation that justifies the abolition of the use of these terms in Soil Science. We consider that the most correct is to call it “Ca-Mg-K-Na saturation”, which, despite being long, would refer directly and without any misinterpretation of the terminology. In Soil Fertility, the “base saturation” is often calculated only as a function of the sum of Ca, Mg, and K, since the Na content is negligible in most tropical and subtropical soils. Thus, one could use the term “Ca-Mg-K saturation”. Likewise, it is also suggested to abolish the use of the term “sum of bases” and use the term “sum of Ca-Mg-K” or “sum of Ca-Mg-K-Na” instead when necessary.

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.

Resumo O objetivo deste trabalho foi avaliar alterações nas propriedades químicas do solo e o limite crítico ambiental para o fósforo (LCA-P), em vinhedos da região sul do estado de Santa Catarina, Brasil. Amostras de solo foram coletadas às profundidades do solo 0-5, 5-10, 10-20 e 20-40 cm, em vinhedos com 22, 36 e 60 anos de idade, e em uma área de mata nativa adjacente utilizada como referência. Os seguintes parâmetros foram analisados: granulometria, pH em água, e teores trocáveis de Al, para cálculo de acidez potencial e saturação por Al; e teores disponíveis de P e K e teores trocáveis de Ca e Mg, para determinação de saturação por bases, capacidade de troca de cátions e matéria orgânica do solo (MOS). Em comparação ao solo da mata, os solos dos vinhedos apresentaram aumento nos valores de pH, nos níveis de P, K, Ca, Mg, Cu, Zn e MOS, e na saturação por bases, além de redução na saturação de Al, com efeitos mais acentuados nas áreas com maior tempo de cultivo. Os vinhedos da região sul de Santa Catarina apresentam alterações nas propriedades químicas do solo, com o tempo, e teores de P acima do LCA-P, pelo menos em uma das camadas do solo.

Abstract The objective of this work was to evaluate changes in the soil chemical properties and the critical environmental limit for phosphorus (CEL-P) in vineyards, in the southern region of the state of Santa Catarina, Brazil. Soil samples were collected at 0-5, 5-10, 10-20, and 20-40 cm soil depths, in vineyards aged 22, 36, and 60 years, and in the area of an adjacent native forest. The following parameters were analyzed: granulometry, pH in water, and exchangeable Al levels, to obtain potential acidity and Al saturation; and available levels of P and K, and exchangeable levels of Ca and Mg, to determine base saturation, cation exchange capacity; and soil organic matter (SOM). In comparison with the forest soil, the vineyard soils showed increased pH values, P, K, Ca, Mg, Cu, Zn, and SOM levels, and base saturation, as well reduced Al saturation, with more accentuated effects in areas with the longest cultivation time. The vineyards show changes in soil chemical properties with time and P levels above the CEL-P, at least in one of the soil layers.

Resumo A seleção de porta-enxertos com características de interesse, como resistência a pragas e doenças, e compatibilidade com copa capaz de produzir frutos atrativos ao mercado, revolucionou as frutíferas em todo o mundo. No entanto, o enorme potencial das plantas de serem selecionadas com base em sua eficiência de absorção de nutrientes ainda não foi devidamente explorado; isso pode ser feito com base no conhecimento dos parâmetros cinéticos, como influxo, velocidade máxima de absorção, constante de afinidade do íon com o transportador e concentração mínima. A adaptação de uma metodologia elaborada para safras anuais, para definição de parâmetros cinéticos, bem como o desenvolvimento brasileiro do software Influx possibilitaram não só selecionar porta-enxertos de pessegueiro com diferentes capacidades de absorção de nutrientes, mas também observar a influência da enxertia de uma determinada cultivar copa na capacidade do porta-enxerto de absorver determinado nutriente do solo. Assim, porta-enxertos e cultivares de árvores frutíferas sempre podem ser selecionados com base em características desejadas pelos fruticultores e consumidores, com ênfase na produtividade e na qualidade dos frutos. Eles também podem ser mais eficientes na absorção de nutrientes de solos de baixa fertilidade natural que requerem maiores quantidades de nutrientes, fato que pode aumentar a racionalização do uso de fertilizantes e reduzir os processos de contaminação ambiental resultantes de aplicações excessivas de nutrientes.

Abstract The selection of rootstocks presenting traits of interest, such as resistance to pests and diseases, and compatibility with scion capable of producing fruits attractive to the market, has revolutionized fruit crops worldwide. However, the enormous potential of plants to be selected based on their nutrient uptake efficiency is yet to be properly explored; it can be done based on knowledge about kinetic parameters such as Influx, Maximum uptake velocity, Constant ion affinity with the carrier, and Minimum concentration. The adaptation of a methodology elaborated for annual crops to set kinetic parameters, as well as the Brazilian development of the Influx software, enabled selecting not only peach rootstocks with different nutrient uptake capacities, but also observing the influence the grafting of a particular cultivar crown has on rootstock’s ability to uptake a given nutrient from the soil. Thus, fruit tree rootstocks and cultivars can always be selected based on traits desired by fruit growers and consumers, with emphasis on yield and quality of fruits. They can also be more efficient in taking up nutrients from low natural-fertility soils that require lower nutrient amounts, a fact that increases fertilizer use rationalization and reduces environmental contamination processes resulting from excessive nutrient applications.

ABSTRACT: This study evaluated P pools after nine years of successive application of either pig slurry (PS) or deep pig litter (DL) in a no-till Ultisol from southern Brazil. The experiment was established in Dec 2002 with the treatments control, application of 90 and 180 kg N ha−1 N as PS and as DL. In Mar 2010, soil samples were taken at six layers up to 30 cm deep. Total organic and inorganic P were assessed by the ignition method, and P compounds classes were evaluated by 31P-NMR spectroscopy. Total soil P increased proportionally with the P amount applied via DL and PS. Only DL application increased soil organic P, mainly at the highest dose and in the uppermost soil layers. The application of high doses of manure to these soils under no-till to meet crop N demands significantly increased P accumulation at the soil surface, especially with DL. This, in turn, increases the risk of contamination of water bodies due to P transfer from soil to rivers via runoff. The ignition method overestimates organic P compared to P-NMR. The highest proportion of organic P estimated by the ignition and P-NMR methods, at surface layers in the control suggests that inorganic P is added to the plots treated, increasing inorganic P and decreasing organic P. Moreover, with no P additions to the control, inorganic soil P is removed by plants, causing an apparent increase in the organic P proportion.

Objetivou-se avaliar os teores de carbono orgânico total (COT) e carbono das frações oxidáveis em agregados biogênicos e fisiogênicos em áreas com aplicação de dejeto líquido de suínos (DLS) e cama sobreposta de suínos (CSS). Após 10 anos do uso de dejetos suínos (DS) na sucessão aveia/milho, coletaram-se amostras indeformadas de solo nas camadas de 0-5 e 5-10 cm, nos tratamentos sem aplicação de DS (testemunha), com aplicação de DLS e CSS em dose equivalente a uma e duas vezes a recomendação de N para o milho e aveia, respectivamente. Os agregados foram separados conforme a via de formação em biogênicos e fisiogênicos. Em seguida, estes agregados foram separados em macro, meso e microagregados. Nestes agregados determinaram-se o COT e apenas nos macroagregados para o C das frações oxidáveis (F1, F2, F3 e F4). A aplicação de DLS aumenta os teores de COT nos microagregados enquanto que o uso da CSS aumenta o conteúdo de COT nos macroagregados. O uso de CSS por longo tempo aumenta o carbono lábil (F1) e recalcitrante (F4) em comparação aos DLS e a testemunha. As frações de carbono oxidáveis permitiram evidenciar diferenças entre os agregados biogênicos e fisiogênicos, sendo maiores nos agregados biogênicos.

The objective of this study was to evaluate the total organic carbon (TOC) and carbon contents of the oxidizable fractions in biogenic and physicogenic aggregates in areas with pig slurry (PS) and deep litter (DL). After 10 years of use of pig manure (PM) in a crop succession with black oat/maize, undisturbed soil samples were collected in the 0-5 and 5-10 cm layers, in the treatments without PM (control) application, with application of PS and DL at a dose equivalent to one and two times the N recommended for maize and black oat, respectively. The aggregates were separated according to the biogenic and physicogenic formation pathway. Then, these aggregates were separated into macro, meso and microaggregates. In these aggregates the TOC was determined in the macro, meso and microaggregates and only in the macroaggregates for the C of the oxidizable fractions (fractions F1, F2, F3 and F4). Application of PS increases the TOC contents in the microaggregates while the DL increases TOC in macroaggregates. The use of DL for a long time increases the labile carbon (F1) and recalcitrant carbon (F4) in comparison to PS and control. Oxidizable carbon fractions showed differences between biogenic and physicogenic aggregates, being greater in the biogenic aggregates.

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.

RESUMO O objetivo do estudo foi avaliara dinâmica de decomposição de resíduos de culturas num pomar de pereiras no Brasil. Resíduos de aveia, nabo forrageiro, azevém e vegetação espontânea foram adicionados em sacos de decomposição depositados à superfície do solo nas linhas de cultivo das pereiras. Após 0, 21, 36, 56 e 136 dias, a matéria seca e os teores de carbono, lignina, celulose, componentes não estruturais e nitrogênio (N), fósforo (P), potássio (K), cálcio (Ca) e magnésio (Mg) foram determinados. Os resíduos de vegetação espontânea apresentaram o maior tempo de semi-vida em comparação com as culturas de cobertura cultivadas, enquanto os resíduos de aveia apresentaram as taxas de decomposição da matéria seca mais rápidas (2-3 vezes maior). O nabo forrageiro e o azevém apresentaram os maiores teores de matéria seca remanescente (26-36%) e a maior liberação de nutrientes. Os resíduos de nabo forrageiro e azevém liberaram 85 kg N ha-1, 67 kg P ha-1, 48 kg K ha-1, 16 kg Ca ha-1 e 9 kg Mg ha-1. O nabo forrageiro poderá beneficiar a nutrição mineral de fruteiras, enquanto a vegetação espontânea poderá contribuir para proteger o solo da erosão e para aumentar o teor de carbono orgânico acumulado no solo num longo prazo.

ABSTRACT Our objective was to evaluate the dynamics of decomposition of crop residues in a pear orchard in Brazil. Residues of oat, oilseed radish, ryegrass and spontaneous vegetation were placed in litter bags and deposited at surface soil in the inter-row spacing of pear trees. After 0, 21, 36, 56 and 136 days, the dry matter, carbon, lignin, cellulose, non-structural components, and nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) concentrations were determined. Spontaneous vegetation residues had the longest half residence time compared to the introduced cover crops, while oat residues presented faster dry matter decomposition rates (2-3 fold higher). Oilseed radish and ryegrass showed the highest final remaining dry matter (26-36%), and the largest nutrients release. Oilseed radish and ryegrass residues released 85 kg N ha-1, 67 kg P ha-1, 48 kg K ha-1, 16 kg Ca ha-1, and 9 kg Mg ha-1. Oilseed radish can potentially benefit mineral nutrition of fruit trees, whereas the spontaneous vegetation is recommended to protect the soil agains the erosion and to contribute to the soil organic carbon stock in the long term.

ABSTRACT South American natural grasslands are composed of several species with different growth strategies, with variations in specific leaf area (SLA), leaf dry matter content (LDMC), specific root length (SRL) and specific root area (SRA). The objective of this study was characterizing in grasses cultivated with different levels of phosphorus (P) in the soil if species with higher leaf and root area production per unit of dry matter have higher tissue P concentration, P use efficiency and higher dry matter yield. The plant species were grown in a greenhouse in pots with 5 kg of soil in a completely randomized design with four replicates and two conditions of P availability: addition of 60 mg kg-1 soil and without addition of P. The species with the highest SRA had a higher leaf and root P concentration. The higher production of leaf or root surface area per unit of dry matter did not represent higher tissue P use efficiency. The group formed by species of genre Paspalum had a higher leaf and root P use efficiency, therefore, areas composed of this genre are preferred for P fertilization.

Resumo: O objetivo deste trabalho foi avaliar a produtividade e a composição do mosto de videiras 'Cabernet Sauvignon' e 'Chardonnay' submetidas a aplicações de fósforo em solo de região de altitude no Sul do Brasil, durante três safras. Os experimentos 1 e 2 foram realizados em vinhedos comerciais de 'Cabernet Sauvignon' e de 'Chardonnay', respectivamente, no município de Água Doce, na região Meio-Oeste do estado de Santa Catarina. O solo dos dois vinhedos foi classificado como Cambissolo Húmico. A fonte de P utilizada foi o superfosfato triplo (45% de P2O5). De 2011 a 2013, no florescimento, foram aplicados 0, 10, 20, 40 e 80 kg ha-1 de P2O5 na projeção da copa, na superfície do solo, sem incorporação, em ambos os vinhedos. Avaliaram-se concentração de P no solo e na folha, variáveis de produção e qualidade do mosto. O incremento na disponibilidade de P diminuiu os valores de acidez total titulável e de ácido tartárico no mosto da videira 'Cabernet Sauvignon' na safra de 2013/2014 e aumentou os valores de pH e sólidos solúveis totais no mosto da videira 'Chardonnay' na safra de 2011/2012. A aplicação de fósforo no solo aumenta os níveis de fósforo disponível, mas não resulta em maiores produtividades das videiras 'Cabernet Sauvignon' e 'Chardonnay'.

Abstract: The objective of this work was to evaluate the yield and must composition of 'Cabernet Sauvignon' and 'Chardonnay' grapevines subjected to phosphorus applications to a soil from a high-altitude region of Southern Brazil, during three crop seasons. Experiments 1 and 2 were carried out in 'Cabernet Sauvignon' and 'Chardonnay' commercial vineyards, respectively, in the municipality of Água Doce, located in the Midwestern region of the state of Santa Catarina. The soil from the two vineyards was classified as a Typic Humicryept. The used source of P was triple superphosphate (45% P2O5). From 2011 to 2013, at flowering, a total of 0, 10, 20, 40, and 80 kg ha-1 P2O5 were applied in the crown projection area, to the soil surface, without incorporation, in both vineyards. Soil and leaf P concentration, yield parameters, and must quality were evaluated. The increase in P availability decreased total titratable acidity and tartaric acid in the must of the 'Cabernet Sauvignon' grapevine in the 2013/2014 crop season and increased pH and total soluble solids in the must of the 'Chardonnay' grapevine in the 2011/2012 crop season. Phosphorus application to the soil increases the levels of available phosphorus, but does not result in higher yields for 'Cabernet Sauvignon' and 'Chardonnay' grapevines.

RESUMO A aplicação de doses de fósforo (P) no solo pode aumentar o crescimento de espécies arbóreas nativas de interesse econômico e ambiental, como a Cordia trichotoma. Assim, esta pesquisa tem por objetivo avaliar parâmetros morfológicos e fisiológicos em mudas de C. trichotoma cultivadas em solo com aumento do teor de P. O experimento foi conduzido em casa de vegetação, em vasos com 2,5 dm-3 de solo, com quatro doses de P (0, 150, 300 e 450 mg dm-3) e seis repetições. O teor de P no solo, as concentrações de P nas folhas, os atributos morfológicos (altura, diâmetro do coleto, matéria seca aérea, matéria seca radicular e área foliar) e os atributos fisiológicos (teor de pigmentos fotossintéticos e fluorescência da clorofila a) foram determinados aos 180 dias após o transplante. O incremento no teor de P disponível no solo permitiu maior absorção desse elemento pelas raízes das plantas, elevando a concentração nas folhas. Isso favoreceu o metabolismo energético das plantas, proporcionando maior crescimento. Além disso, o maior influxo e acúmulo de P na planta quando utilizado 450 mg dm-3, incrementou a concentração dos pigmentos fotossintéticos e elevou a capacidade fotossintética das mudas de C. trichotoma. O maior aproveitamento da energia luminosa pelo fotossistema II (Fv/Fm = 0,76) foi observado nas mudas cultivadas com 450 mg dm-3 de P, com aumento de 95% quando comparadas às mudas sem adição de P. Assim, percebemos que essa espécie arbórea, é exigente e responsiva em relação ao maior teor de P disponível no solo.

ABSTRACT The application of phosphorus (P) doses in the soil can increase the growth of native tree species of economic and environmental interest, such as Cordia trichotoma. Thus, this research aims to evaluate the morphological and the physiological parameters in C. trichotoma seedlings, cultivated in soil with increased P content. The experiment was conducted under greenhouse conditions in pots with 2.5 dm-3 of soil, four doses of P (0, 150, 300 and 450 mg dm-3), and six replicates. P content in the soil, P concentrations in the leaves, morphological attributes (height, stem diameter, aerial dry matter, root dry matter, and leaf area) and physiological attributes (photosynthetic pigment content and chlorophyll α fluorescence) were determined 180 days after transplantation. The increase in the available P content in the soil allowed greater absorption of this element by the plant’s roots, increasing the concentration in the leaves, and therefore favoring the energetic metabolism of the plants. In addition, the higher influx and accumulation of P in the plant when 450 mg dm-3 was used, increased the concentration of the photosynthetic pigments and increased the photosynthetic capacity of the C. trichotoma seedlings. The highest use of the light energy by photosystem II (Fv/Fm = 0.76) was observed in the seedlings cultivated with 450 mg dm-3 of P, with a 95% increase when compared to seedlings without P. Thus, we observed that this tree species is demanding and responsive to the higher P content available in the soil.