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Genus Eucalyptus can be grown in different soils worldwide, although it is not always ready to fulfill plants' nutrient demands. Whenever such nutrient shortage happens, it is necessary applying the nutrients missing, which can be established based on the critical levels and sufficiency ranges (SRs) of nutrients in leaves or by multivariate mathematical models, such as the composition nutrient diagnosis (CND). This study aimed to investigate the nutritional status of Eucalyptus plantations in Brazil, based on the CND method. A total of 119 12-month-old Eucalyptus saligna (E. saligna) plantations were sampled in the Rio Grande do Sul State (RS), Southern Brazil. Nutrient concentration in leaves and the diameter at breast height (DBH) was measured. The E. saligna nutritional status was calculated through the CND method. High- and low-yield populations were set based on DBH of 4.2 cm. The SRs proposed by the CND method were narrower than the ones proposed by official recommendations for Eucalyptus, especially for magnesium (Mg), boron (B), and iron (Fe). The [CND- r.sup.2] index recorded for each nutrient generated a limitation order for nutrients. The greater accuracy of the recommendations proposed by the CND method, compared with univariate and bivariate methods, contribute to reducing the use of fertilizers. Key words: leaf analysis, diameter at breast height, composition nutritional diagnosis, planted forest, nutrient diagnosis, 1. Introduction Genus Eucalyptus stands out for economic relevance worldwide since its culture accounts for multiple goods from raw material production to transformation, such as paper, charcoal, cellulose, laminates, and [...]

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This study aimed to evaluate the absorption, partitioning, and redistribution of nutrients by phenological stage of the maize crop, under the edaphoclimatic conditions of the municipality of Brejo, Maranh~ao, Brazil. The experiment was carried out in a Yellow Argisol, under a randomized block design, with seven treatments corresponding to the phenological stages V5, V8, VT, R1, R3, R5, and R6, and four replicates. The plant was partitioned into leaves, stalk, reproductive organs (tassel, straw, cob), and grains to determine the concentrations of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn. The accumulation of nutrients in each organ in the different phenological stages was estimated based on the values of dry weight and nutrient concentrations. A slow accumulation of dry weight was observed in the maize plant until the flowering stage (VT), a pattern also observed for the nutrients P, Mg, S, and Cu. Nutrients N, K, Ca, B, Fe, Mn, and Zn showed values close or superior to 50% of the maximum accumulated up to VT. The decreasing order of nutrient accumulation was N>K>P>Mg> S>Ca>Fe>Zn>Mn>Cu>B. The nutrients with the highest harvest rates were P>N>Mg>S>Zn (0.84, 0.74, 0.72, 0.69, and 0.51, respectively). N, K, Ca, B, Zn, Fe, and Mn are the most absorbed nutrients in the initial stage of crop development. The nutrients that are absorbed in greater quantity after flowering are P, S, Mg, and Cu. The degrees day sum showed no effects on the maize crop cycle under the edafoclimatic conditions of this study. [ABSTRACT FROM AUTHOR]

The pressing of green coconut shell, aiming at the production of powder or fiber, used as raw material by the industry, generates large amounts of the green coconut shell liquid (GCSL), whose incorrect disposal results in environmental impacts. This study evaluated the potential use of GCSL as a source of potassium for young dwarf coconut plants. The experiment was carried out in pots, in a completely randomized design, applying seven treatments, comprising five doses of GCSL, which corresponded to 0% (G0), 50% (G50), 100% (G100), 150% (G150) and 200% (G200) of the need for K2O of the plants, a treatment with mineral fertilizer, corresponding to 100% of K2O supplied as KCl (K100), and another containing 50% of K2O as KCl and 50% as GCSL (G50 + K50), with five replicates. One hundred and twenty days after transplanting the seedlings, soil chemical attributes as well as growth and nutritional status of dwarf coconut plants were evaluated. Increase in GCSL doses altered soil fertility and reduced the percentage of live leaves of dwarf coconut. The G50 + K50 treatment did not differ from K100 for all variables of growth, except for % of live leaves, indicating the possibility of replacing 50% of the K2O dose recommended for the first year of dwarf coconut cultivation with GCSL. [ABSTRACT FROM AUTHOR]

Cashew plants have shown, a few days after planting in the field, interveinal chlorosis in young leaves and, as the symptoms become worse, the leaves are completely chlorotic, a nutritional disorder that is related to iron (Fe) deficiency. Thus, the objective was to evaluate the growth and physiological responses of grafted seedlings of dwarf cashew as a function of Fe doses. The experiment was conducted in a greenhouse, in a completely randomized design, with four replicates. Treatments consisted of five doses of Fe (0; 2.5; 5; 7.5 and 10 mg L−1), using iron sulfate (20% Fe) as source. The following parameters were evaluated: growth variables – height, number of leaves, leaf area, stem diameter and dry matter (roots, shoots and total); and physiological variables – photosynthesis (A), stomatal conductance (gs), transpiration (E), water use efficiency (WUE), instantaneous carboxylation efficiency (A/Ci), photosynthetic pigments and relative chlorophyll index. Fe deficiency affected the photosynthetic process, causing significant reductions in the evaluated characteristics, indicating the need for its adequate supply for the growth of dwarf cashew plants. [ABSTRACT FROM AUTHOR]

The leaf reference values for pineapple available in the literature were obtained using bivariate methods that aim to reach maximum yield; however, plant nutrition also influences the fruit quality. This study aimed to generate reference values for the 'Pérola' pineapple grown in the Paraíba State using compositional nutrient diagnosis (CND) in order to maximize fruit yield and quality. The study used data of fruit weight, soluble solids (SS), titratable acidity (TA), SS/TA ratio, and leaf concentrations of N, P, K, S, Ca, Mg, Cu, Fe, Zn, Mn, and B of the pineapple cultivar 'Pérola' originated from fertilization trials. The treatments consisted of the combination of two matrices: the modified Pan Puebla III matrix and the Baconian matrix, which assessed the variation in the levels of N, P, K, and S and the variation in the levels of liming and micronutrients, respectively, totaling 30 treatments in a randomized block design with 90 plots and three replications per experiment. The CND method was used to obtain reference values. There were differences in the mean nutrient concentrations between the high and low-quality populations; however, there was no difference between the nutrient concentrations that promoted the highest fruit weight and those that promoted the highest quality index. The sufficiency ranges for 'Pérola' pineapple obtained by CND methodology aiming at the quality index and yield were: N:10.9–14.2; P:1.2–1.6; K: 35.6–42.8; S: 1.0–1.5; Ca: 2.3–3.7; Mg: 1.5–2.2 g kg−1; Cu: 1.1–3.1; Fe: 30.4–52.6; Zn: 4.0–8.5; Mn: 129.2–175.9; and B: 18.8–27.4 mg kg−1. [ABSTRACT FROM AUTHOR]

O presente trabalho objetivou avaliar o desenvolvimento de mudas de goiabeira em resposta a doses e modos de aplicação de fertilizante fosfatado. As mudas de goiabeira foram transplantadas em conjuntos de vasos (sacos plásticos, 18 x 28 cm) geminados, contendo em cada lado 2,8 dm³ do subsolo de um Argissolo (P resina = 1 mg dm-3), de modo que a metade do sistema radicular ficasse em cada vaso. Usou-se um fatorial 2 x 3 x 2 + 1 (testemunha, sem fósforo), em 5 blocos casualizados. As doses de 70; 140 e 280 mg de P dm-3 de solo, na forma de superfosfato triplo, foram aplicadas de dois modos diferentes com relação ao solo (distribuído em todo o volume do solo ou localizado a 1/3 de profundidade) e dois modos diferentes com relação às raízes (dividindo-se a dose igualmente entre os dois vasos do conjunto ou aplicando-se a dose total em um único vaso). Cem dias após o transplante, verificou-se maior acúmulo de P e maior produção de matéria seca nas plantas que receberam adubação fosfatada. As mudas de goiabeira responderam positivamente à adubação fosfatada, sendo a dose próxima de 100 mg de P dm-3 de solo suficiente para o bom desenvolvimento das plantas. Doses acima de 200 mg de P dm-3 promoveram redução do crescimento das mudas de goiabeira. A disponibilização de fósforo à metade ou a todo o sistema radicular da goiabeira não afetou o suprimento desse nutriente às mudas e tampouco o seu desenvolvimento. A aplicação do adubo fosfatado distribuído em todo o volume de solo no vaso proporcionou maior desenvolvimento do sistema radicular e menor desenvolvimento da parte aérea das mudas de goiabeira, comparado à aplicação localizada do adubo a 1/3 de profundidade.

O subsolo, normalmente utilizado para produção de mudas de frutíferas, apresenta baixa concentração de zinco e, assim, existe grande probabilidade de resposta à aplicação deste micronutriente. Considerando a falta de informações sobre o assunto, procurou-se avaliar o efeito da aplicação de zinco ao substrato de produção das mudas de goiabeira e acompanhar os efeitos no desenvolvimento, na produção de matéria seca e no estado nutricional das plantas. O delineamento experimental foi em blocos ao acaso, com cinco tratamentos e cinco repetições. As doses de zinco, na forma de sulfato de zinco, foram: 0; 2; 4; 6 e 8 mg dm-3 de Zn. No plantio, as mudas receberam doses de N, P, K e B de 300; 100; 150 e 0,5 mg dm-3, respectivamente. O experimento foi conduzido em viveiro telado, em vasos com 2,8 dm³ de substrato de um Argissolo Vermelho-Amarelo. Após 135 dias do plantio, avaliaram-se: a altura, a área foliar e a matéria seca da parte aérea e das raízes, bem como os teores de macronutrientes e de Zn. As mudas de goiabeira responderam positivamente à aplicação de zinco. O maior desenvolvimento das mudas esteve associado à dose de 2 mg dm-3 de Zn. Doses iguais ou superiores a 4 mg dm-3 causaram redução significativa no desenvolvimento e no acúmulo de macronutrientes nas mudas de goiabeira.