Josinaldo Lopes Araujo

Crescimento e teores de boro em plantas de eucalipto (Eucalyptus citriodora) cultivadas em dois latossolos sob influência de doses de boro e disponibilidade de água

3de solo. Utilizou-se o delineamento experimental inteiramente casualizado, em esquema fatorial 5 x 2 x 2, sendo cinco doses de B (0,00; 0,25; 0,75; 2,25; e 6,25 mg kg -1 ); e dois tipos de Latossolo: Latossolo Vermelho-Escuro (LE) e Latossolo Vermelho-Amarelo (LV) e duas tensoes hidricas (-0,033 e -0,010 MPa), com quatro repeticoes. Os resultados indicaram que tanto o LV quanto o LE, nas suas condicoes naturais, nao supriram as exigencias de B em Eucalyptus citriodora. Contudo, os maiores incrementos na producao de materia seca das plantas foram observados em baixas doses de B aplicadas. A umidade do solo e um fator importante no aproveitamento de B do solo pelo Eucalyptus citriodora.

Crescimento inicial de arbóreas nativas em solo salino-sódico do nordeste brasileiro tratado com corretivos

Initial growth of native trees on saline-sodic soil from northeastern Brazil using amendments Salts and sodium in excess on soil is one of the main factors that contribute to chemical degradation of soils from arid and semiarid irrigated areas. The objective of this work was to evaluate the soil amendments effect on the recovery of a soil degraded by salts and sodium in excess and on the initial growth of five native trees of Caatinga biome on saline-sodic soil. Two experiments were carried out in a greenhouse at CCTA/UFCG, using samples of a saline-sodic soil. The first experiment consisted of five soil amendment treatments: without correction, agricultural gypsum at the rate of 100% of the gypsum need (NG), agricultural gypsum at the rate of 50% NG + organic matter (OM), elementary sulfur (S) at the rate of 100% NG and elementary sulfur at the rate of 50% NG + OM, with 15 replicates. In the second experiment, the treatments were conducted in a factorial scheme 5 x 5, with five native trees species [tamboril (Enterolobium contortisiliquum), sabia (Mimosa caelsalpiniifolia), jurema-preta (Mimosa tenuiflora), craibeira (Tabebuia aurea) e pereiro (Aspidosperma pyrifolium) and with the five soil amendment treatments from the first

Interação fosfito e fosfato no crescimento e na nutrição fosfatada do feijoeiro em solução nutritiva

The use of phosphite as a fungicide or supplementary source of phosphorus (P) has been intensified in recent years, however, little is known about its effects on important crops such as common bean. This work aimed to evaluate the effect of phosphite on growth and phosphate nutrition of bean plants. Two experiments in an completely randomized design were conducted in nutrient solution in a green house, from January to March 2008. In the first experiment, the treatments consisted of a 5 x 2 factorial design, with five P concentrations in the nutrient solution (0.5; 10; 20; 30 and 60 mg L-1) and two P forms: phosphite (Phi) and phosphate (Pi), with four replications. In the second experiment, the treatments consisted of five proportions of Pi: Phi in nutrient solution (100:0, 25:75, 50:50, 75:25 e 100:0), with five replications. The results showed that the shoot and root dry matter of plants grown with phosphite as the only form of P or with high proportions of Phi in relation to Pi, was drastically reduced, resulting in low P accumulation in these tissues. In conclusion, phosphate cannot be replaced by phosphite in phosphate nutrition of common bean, and has no effect on common bean under adequate phosphate supply. At no or low phosphate supply, severe phosphite toxicity symptoms were observed in the common bean plants, which are very sensitive to this anion.

Silício como amenizador da fitotoxicidade de zinco em plantas jovens de Eucalyptus urophylla cultivadas em solução nutritiva

Zn is an essential micronutrient for the growth and metabolism of plants, but when present in toxic levels in the environment, it can affect the the development of plants. Among the several beneficial effects of silicon (Si), it presents an effect in the decrease or elimination of the adverse effects of heavy metals in the environment. The objective of this work was to evaluate the effect of Si in the alleviation of Zn toxicity on the growth and mineral nutrition of Eucalyptus urophylla seedlings cultivated in nutrient solution. Seedlings of Eucalyptus urophylla were grown in pots containing 3L of Clark nutrient solution, in a 6 x 2 factorial design, using six Zn concentrations (0, 2, 50, 150, 300 and 450 µmol L-1 as ZnSO4 7H2O) and two of Si (0 and 1.78 mmol L-1 of Si as potassium silicate). After eight weeks, plant morphologic traits, dry matter production and content and nutrient utilization were evaluated. The increase of Zn concentrations in the nutrient solution provided higher toxicity in the roots than in the shoots. The addition of the Si alleviated the negative effect of the excess Zn on plant growth, but presented little effect on the nutrient content in these tissues. The silicon addition in the nutrient solution provided a more efficient use of P, Ca, Mg and S for the Eucalyptus urophylla plants.

Crescimento e respostas fisiológicas de espécies arbóreas em solo salinizado tratado com corretivos

The study aimed to evaluate the effect of amendments on the reclamation of a saline-sodic soil and on growth and physiological responses of native species of trees from Caatinga ecosystem. Two experiments were carried out in a greenhouse, in a completely randomized design. In first experiment, five treatments of soil reclamation were evaluated with four replications. In the second experiment the treatments were arranged in a factorial scheme 5 x 4, related to the native species of trees from Caatinga ecosystem and five treatments of reclamation evaluated in the first experiment with three replications. The application of amendments, especially elemental sulfur, decreased salinity and sodicity of salinized soil, favoring the growth and dry matter production of plants. The Caesalpinia ferrea specie was the one that was more tolerant to excess of salts and sodium. Excess of salts and sodium in the soil increased the concentration of sodium and sodium/potassium ratio in the shoots and decreased stomatal conductance and intercellular CO2 concentration in the leaves.

Crescimento e nutrição mineral de cebolinha verde cultivada hidroponicamente sob diferentes concentrações de N, P e K

Em cultivos hidroponicos de hortalicas folhosas destacam-se, dentre os fatores que influenciam a producao e qualidade do produto, as exigencias nutricionais da cultura. Objetivou-se, com este trabalho, avaliar o efeito de concentracoes de N, P e K sobre a producao de materia seca e a nutricao mineral em cebolinha ‘T odo ano’ (Allium fistulosum L.), cultivada em condicoes hidroponicas. Foram conduzidos tres experimentos, um com cada nutriente em tres niveis: deficiente, adequado e excessivo. Empregou-se o delineamento inteiramente casualizado, em esquema de parcelas subdivididas no tempo, com quatro repeticoes e dez plantas por parcela. Aos 15, 30, 45 e 60 dias apos o transplante (DAT), foi avaliada a producao de materia seca da parte aerea e de raizes. Aos 45 e 60 DAT, avaliaram-se os teores e os acumulos totais de N, P e K e os teores de Ca e Mg da parte aerea da planta. Em cultivos hidroponicos, as deficiencias de N e P sao mais limitantes que a de K ao crescimento da cebolinha cultivar ‘T odo Ano’, sendo que niveis baixos de P afetam principalmente o crescimento do sistema radicular da planta. A deficiencia de N afeta a absorcao de P, K, Ca e Mg. O excesso de N em cebolinha manifesta-se pelo crescimento excessivo da parte aerea e pelo aumento da flacidez das folhas. Os excessos de P e de K na solucao nutritiva nao provocam sintomas visuais de toxicidade de P ou de K, mas niveis excessivos de K diminuem os teores de Ca e de Mg da parte aerea da planta. Palavras-chave: Allium fistulosum L., cultivo hidroponico, toxicidade, deficiencia nutricional, diagnose nutricional.

Produção, aspectos nutricionais e fisiológicos de alface sob adubação foliar com Spirulina platensis

Objetivou-se avaliar a influencia de concentracoes do fertilizante orgânico a base de Spirulina platensis sobre a producao, crescimento, teores de N, P, K e sodio e sobre as trocas gasosas de alface cv. Elba em condicoes de campo. Utilizou-se o delineamento de blocos ao acaso, com seis tratamentos, constituidos das concentracoes do fertilizante (0; 1,5; 3,0; 4,5; 6,0 e 7,5%) com seis repeticoes. No ponto de colheita da cultura foram avaliadas variaveis de producao e crescimento, os teores de nitrogenio, fosforo, potassio e sodio, bem como, as trocas gasosas das plantas com o medidor de gas infravermelho (IRGA). Os resultados obtidos mostraram que as concentracoes do fertilizante, nao afetaram a producao, o crescimento, os teores de nutrientes avaliados, assim como nao influenciaram as trocas gasosas das plantas. Production, mineral nutrition and physiological aspects of lettuce under foliar fertilization with Spirulina platensis Abstract : The objective of this study was to evaluate the influence of concentrations of organic fertilizer based on Spirulina platensis on yield, growth, in N, P, K and sodium contents and on gaseous changes of lettuce cv. Elba in field conditions. Use the design of randomized blocks, with six treatments consisting of different concentrations of fertilizer (0; 1.5; 3.0; 4.5; 6.0 and 7.5%) with six replications. At the harvest point were evaluated the growth and production, nitrogen, phosphorus, potassium and sodium, as well as gas exchange plant with infrared gas meter (IRGA). The results showed that the fertilizer concentrations did not affect production, growth, levels of nutrients evaluated, and did not influence the gas exchange of plants.

Phosphite and phosphate in the accumulation and translocation of nutrients in common bean1

et al. 2006, Moor et al. 2009, Gómez-Merino & Trejo-Téllez 2015). Many beneficial effects of phosphites on crops have been reported in some studies. Tambascio et al. (2014) observed that phosphite provided an increase in the emergence of tubers, leaf area and mycorrhizal colonization in potatoes. Estrada-Ortiz et al. (2013) reported that the use of phosphite in the nutrient solution increased the concentration of free amino

Biomass production, B accumulation and Ca/B ratio in Eucalyptus under various conditions of water availability and B doses

Soils destined for forest crops are often limiting with respect to boron (B) and in several eucalyptus crops boron deficiency has been found to be a common occurrence. The objective of this study is to evaluate biomass production, B accumulation and Ca/B ratio in eucalyptus cultivated under different conditions of soil, water availability and doses of B. To that end, an experiment was conducted using a completely randomized design with a 5 x 2 x 2 factorial arrangement consisting of five doses of B (0.00, 0.25, 0.75, 2.25 and 6.25 mg kg-1), two types of soil, namely a Dark Red Latosol (LE) and a Red-Yellow Latosol (LV), and two water tension levels (-0.033 and -0.010 MPa), with four replicates. After plants were grown, determinations were made of Ca and B contents as well as Ca/B ratios in different portions of the plants. Accumulation of B was obtained from the ratio of its contents to dry biomass in each plant portion. It was found that, under natural conditions, both Dark Red Latosol and Red-Yellow Latosol fail to meet the nutritional requirements for B in eucalyptus, potentially being limiting to that species. Overall, soil moisture influenced dry biomass production and accumulation of B only in the case of the more sandy texture soil (Red-Yellow Latosol), denoting that this factor is conditional on soil texture. Ca/B ratio results showed that application of B to the soil without a suitable supply of Ca can lead to an imbalance between these nutrients, with possible implications for plant growth and nutrition.