A utilização adequada da adubação nitrogenada e o aumento da densidade populacional incrementam a produtividade do abacaxizeiro e podem aumentar o retorno econômico. Objetivou-se avaliar a rentabilidade econômica e as características de qualidade pós-colheita do abacaxizeiro Vitória irrigado, sob diferentes fontes e doses de nitrogênio (N), bem como o aumento da densidade populacional. Utilizou-se o delineamento em blocos casualizados, com três repetições, em esquema fatorial 2 x 5 x 4, correspondendo a duas fontes de N (ureia e esterco bovino), cinco doses de N (0 g planta-1, 5 g planta-1, 10 g planta-1, 15 g planta-1 e 20 g planta-1) e quatro densidades (51.282 plantas ha-1, 76.923 plantas ha-1, 90.909 plantas ha-1 e 126.984 plantas ha-1). As fontes de N não interferiram no pH, acidez total titulável e relação sólidos solúveis totais/acidez total titulável (SST/ATT). Entretanto, o teor de SST foi superior nas plantas adubadas com esterco bovino. A densidade de plantas não interferiu na qualidade de pós-colheita dos frutos. O aumento das doses de N fornecidas via ureia e esterco bovino influenciou somente a acidez total titulável dos frutos. Com a adição de 20 g planta-1 de N-esterco e população de 126.984 plantas ha-1obteve-se o máximo rendimento líquido parcial de R$ 132.096,48. No entanto, a dose de 19,75 g planta-1 de N-ureia, na população de 119.686,00 plantas ha-1, resultou em rendimento líquido parcial de R$ 154.997,15.

Cowpea plants produce protein-rich grains and present high yield potential when grown under irrigation and organic fertilization, enabling to substitute part of the mineral fertilizer with sewage sludge, reducing costs and generating environmental benefits. Thus, a field study about residual effect of sewage sludge fertilization on cowpea was developed to evaluate this substitution. The experiment was conducted using a randomized block design with four replications, in a 2×5 factorial arrangement consisted of two fertilization types (residual effect of sewage sludge fertilization, and mineral fertilizers) and five cowpea cultivars (BRS-Pajeu, BRS-Xiquexique, BRS-Marataoa, BRS-Pujante, and BRS-Cauame). The residual fertilizations were from applications of sewage sludge and NPK mineral fertilizers for pineapple crops grown in the area before the cowpea crop. The experiment was conducted using 80,000 plants ha-1 and micro-sprinkler irrigation. Vegetative and yield components, grain yield, and microbiological quality were analyzed. BRS-Pujante had the highest cowpea grain yield (4,124 kg ha-1) and the highest means for vegetative and yield components. The soil with residual sewage sludge fertilization improved the cowpea root growth and grain yield (3,854 kg ha-1); the latter was 19% higher than that of treatments with mineral fertilization. These results were related to the great soil organic matter content provided by the sludge fertilization, which promotes nutrient mineralization, increasing grain yield. Fresh and dry grains of cowpea plants grown under residual effect of sewage sludge fertilization have similar microbiological quality to those of plants grown under mineral fertilization.

-Balanced uptake of micronutrients by the passion fruit plant is essential for increased production and fruit quality. However, similar fertilizer management in varieties with different productive capacities and high levels of nitrogen and potassium can cause nutritional disorders in plants. The objective of this study was to evaluate leaf micronutrient concentrations and contents in passion fruit as affected by two different sampling methods, different N-K fertilization proportions, and different cultivars. The study was conducted in a randomized block design, with three replications, following a 4 × 6 factorial arrangement consisting of four cultivars of yellow passion fruit (BRS Gigante Amarelo, IAC 275, BRS Ouro Vermelho, and BRS Sol do Cerrado) and six application rates ofN-K 2 O fertilizer (0-0, 50-125, 100-250, 150-375, 200-500, and 250-625 kg ha -1 year -1 ). Two leaf sampling methods (leaf located at a position adjacent to the fruit, and leaf located at the end of the fruit-bearing branch) were adopted for nutritional assessment. At 240 days after planting passion fruit seedlings in the experimental area, 20 leaves per plot were sampled. Higher accumulated micronutrient contents were obtained in the adjacent leaves, possibly because of greater leaf weight (more fully developed leaf) compared to the standard leaf. The cultivar IAC 275 had lower concentration and content of Cu, Fe, e Mn in the adjacent leaf, indicating variations in the levels of micronutrients among the cultivars and different micronutrient demands by the cultivars studied. N and K fertilization had less effect on leaf micronutrient concentration and content, but the Zn concentration and content decreased in the standard leaf of the BRS Gigante Amarelo cultivar, and Cu decreased in the standard leaf of the BRS Ouro Vermelho cultivar. Index terms: Passiflora edulis Sims; Cultivars, Leaf content. TEOR E ACÚMULO DE MICRONUTRIENTES EM FOLHAS DE MARACUJAZEIRO SOB MÉTODOS DE AMOSTRAGEM E ADUBAÇÕES N-KRESUMO -A absorção equilibrada dos micronutrientes pelo maracujazeiro é essencial para o aumento da produção e qualidade de seus frutos. No entanto, a utilização de cultivares com distintas capacidades produtivas e doses elevadas de nitrogênio e potássio podem levar a desordens nutricionais nas plantas. Objetivou-se avaliar os teores e acúmulos foliares de micronutrientes em maracujazeiros, sob dois métodos de amostragem foliar e adubação com N e K. O delineamento utilizado foi o em blocos casualizados, com três repetições, no esquema fatorial 4 × 6, consistindo em quatro cultivares de maracujazeiro-azedo (BRS Gigante Amarelo, IAC 275, BRS Ouro Vermelho e BRS Sol do Cerrado) e seis doses de N-K 2 O (0-0; 50-125; 100-250; 150-375; 200-500 e 250-625 kg ha -1 ano -1 ). Foram adotados dois métodos de amostragem foliar (folha localizada na posição adjacente ao fruto e folha localizada no final do ramo frutífero) para a avaliação nutricional. Aos 240 dias após plantio das mudas de maracujazeiro na área experimental, foram amostradas 20 folhas ...

-Nitrogen and potassium fertilization and assessment of adequate nutritional status are essential for increasing fruit production of passion fruit. However, studies related to characterization of the leaf nutrient concentration and content in passion fruit with different production capacities are scarce in the literature in Brazil. The objective of this study was to evaluate macronutrient leaf concentration and content in different parts of the reproductive shoot of yellow passion fruit subjected to different ratios of N and K fertilization. The study was conducted in a randomized block design, with three replications, following a 4 x 6 factorial arrangement consisting of four cultivars of yellow passion fruit (BRS Gigante Amarelo, IAC 275, BRS Ouro Vermelho, and BRS Sol do Cerrado) and six application rates of N-K 2 O fertilizer (0-0, 50-125, 100-250, 150-375, 200-500, and 250-625 kg ha -1 year -1 ). Two leaf sampling methods were adopted (leaf located at a position adjacent to the fruit, and leaf located at the end of the reproductive branch) for nutritional assessment. The leaf located at the adjacent position had lower N, P, K, Mg, and S concentration and higher Ca concentration than the concentrations observed in the standard leaf. However, the higher leaf dry matter in adjacent leaves resulted in increased macronutrient concentration/content. The increase in N-K fertilizations inhibited Ca and Mg content in the leaves adjacent to the fruit of the Gigante Amarelo, IAC, and Ouro Vermelho passion fruit cultivars, but did not affect Ca and Mg content in the standard leaf. The passion fruit cultivars showed different leaf nutrient contents after N-K fertilization, indicating variable nutritional demands and the need for specific diagnostic methods for each cultivar.