ABSTRACT This study aimed to evaluate the effects of nitrogen (N) and phosphorus (P) associated with dry and rainy seasons on the photochemical activity of Opuntia ficus-indica (L.) Mill. cv. Gigante. Combinations of N (10.0, 70.0, 100.0, 130.0, and 190.0 kg ha−1 yr−1) and P2O5 (10.0, 70.0, 100.0, 130.0, and 190.0 kg ha−1 yr−1) were evaluated in the dry and rainy seasons in semi-arid regions. A completely randomized block design with split-plot arrangement was adopted with four replications. In Quixadá, the maximum potential quantum efficiency of photosystem II (Fv/Fm) was 0.82, observed in third-order cladodes (rainy season and N/P 75.6/10.0 kg ha−1 yr−1), while in Tejuçuoca, the maximum Fv/Fm was 0.81, found in 2nd/3rd order cladodes (rainy season and N/P 10.0/190.0 kg ha−1 yr−1). In Quixadá, the maximum electron transport rate (ETR) was 31.6 μmol m−2 s−1 in 2nd/3rd order cladodes (rainy season and N/P 10.0/190.0 kg ha−1 yr−1), and in Tejuçuoca, the maximum ETR was 24.1 μmol m−2 s−1, in second-order cladodes (rainy season and N/P 110.1/10.0 kg ha−1 yr−1). In Quixadá and Tejuçuoca, higher values of Fv/Fm and ETR were observed in the rainy season. In Quixadá, the maximum fluorescence decrease ratio (FDR) was 4.04 in third-order cladodes (rainy season and N/P 10.0/114.8 kg ha−1 yr−1), while in Tejuçuoca, the maximum FDR was 6.93, found in 2nd/3rd order cladodes (rainy season and N/P 190.0/10.0 kg ha−1 yr−1). In Quixadá and Tejuçuoca, there was predominance of higher FDR values in the rainy season. Nitrogen, phosphorus, and water status modulate the photochemical efficiency of cladodes of cactus pear cv. Gigante in semi-arid regions.

ABSTRACT Forage biomass production and water storage (WS) was evaluated in cactus pear cv. Gigante fertilized with combinations of nitrogen (10, 70, 100, 130, and 190 kg ha−1 yr−1 N) and phosphorus (10, 70, 100, 130, and 190 kg ha−1 yr−1 P2O5) in annual (AH) and biennial (BH) harvest frequencies, in Quixadá and Tejuçuoca, Brazil. A randomized complete block design was used in a split-plot arrangement with four replications. In Quixadá, the maximum total forage biomass (TFB) recorded in the AH was 3,522.9 kg ha−1 yr−1 for the N/P2O5 combination of 134.6/190.0 kg ha−1 yr−1, and in the BH, the maximum TFB of 1,583.2 kg ha−1 yr−1 was recorded for the N/P2O5 combination of 114.6/136.8 kg ha−1 yr−1. In Tejuçuoca, the maximum TFB recorded in the AH was 9,783.0 kg ha−1 yr−1 for the N/P2O5 combination of 137.7/190.0 kg ha−1 yr−1, and in the BH, the maximum TFB of 12,124.0 kg ha−1 yr−1 was recorded for the N/P2O5 combination of 190.0/56.8 kg ha−1 yr−1. In Quixadá, the maximum WS recorded in the AH was 39.1 kg ha−1 mm−1 for the N/P2O5 combination of 161.0/190.0 kg ha−1 yr−1, and in the BH, the maximum WS of 11.3 kg ha−1 mm−1 was recorded for the N/P2O5 combination of 113.5/158.7 kg ha−1 yr−1. In Tejuçuoca, the maximum WS recorded in the AH was 196.1 kg ha−1 mm−1 for the N/P2O5 combination of 190.0/190.0 kg ha−1 yr−1, and in the BH, the maximum WS of 265.5 kg ha−1 mm−1 was recorded for the N/P2O5 combination of 190.0/10.0 kg ha−1 yr−1. To achieve the persistence and longevity of the cactus pear cv. Gigante, the management with BH and fertilization with the N/P2O5 combination of 114.6/136.8 kg ha−1 yr−1 (in regions similar to Quixadá) and N/P2O5 combination of 190.0/56.8 kg ha−1 yr−1 (in regions similar to Tejuçuoca) is recommended.

Resumen Los estudios multicéntricos sobre cáncer mamario requieren colaboración interinstitucional, recursos y personal especializado. En México, muchas instituciones prestan estos servicios, con información poco accesible; para mitigarlo, la Sociedad Mexicana de Oncología conformó el Grupo Cooperativo de Investigación de México en Oncología. Objetivo: Describir la infraestructura, personal y actividades de hospitales con atención de pacientes con cáncer mamario en México. Métodos: Se realizó una encuesta a 30 especialistas en cáncer mamario sobre recursos y servicios de sus instituciones. Resultados: Trece (43.3%) especialistas respondieron la encuesta, siendo el 38.5% de Instituciones con Seguro Popular, 23.1% del Instituto Mexicano del Seguro Social y el 38.4% de otras afiliaciones, con una mediana de 300 (50-950) casos nuevos por año. Todas cuentan con cirugía oncológica, radiología mamaria, cuidados paliativos, patología, nutrición y sesiones multidisciplinarias. Todas tienen ultrasonido con transductor para mama, el 92.3% mastografía digital y el 53.8% tomosíntesis y/o resonancia magnética. La detección de ganglio centinela se realiza en el 92.3% de los casos con colorante y el 61.5% con radionúclido. El 92.3% dispone de tamoxifeno, inhibidores de la aromatasa y trastuzumab, y < 40% otras terapias blanco. En el 21.3% existen firmas genéticas y en el 61.5% análisis de cáncer hereditario. Conclusiones: La capacidad institucional para participar en estudios multicéntricos es heterogénea; los pocos recursos en varias instituciones limitan su inclusión en estudios de cáncer mamario.

Abstract Multicenter studies on breast cancer require inter-institutional collaboration, resources and specialized personnel. In Mexico, many institutions provide these services, but their information is not accessible; to mitigate it, the Mexican Society of Oncology formed the Mexican Cooperative Research Groups in Oncology. Objective: To describe the infrastructure, personnel and activities of hospitals with care of patients with breast cancer in Mexico. Methods: A survey was conducted to 30 breast cancer specialists about resources and services of their institutions. Results: 13 (43.3%) specialists answered the survey, 38.5% of Seguro Popular, 23.1% of Instituto Mexicano del Seguro Social, and 38.4% of other institutions, with a median of 300 (50-950) new cases per year. All the institutions have oncological surgery, breast radiology, palliative care, pathology, nutrition and multidisciplinary sessions. All have ultrasound with breast transducer, 92.3% digital mammography, and 53.8% tomosynthesis and/or magnetic resonance. They do sentinel lymph node detection with dye (92.3%) or radionuclide (61.5%). Tamoxifen, aromatase inhibitors and trastuzumab are available in 92.3%, and other target therapies in < 40%. Genetic signatures are done in 21.3% and 61.5% analysis of hereditary cancer. Conclusions: The institutional capacity to participate in multicenter studies is heterogeneous; the few resources in several institutions limit their inclusion to studies of breast cancer.

Resumo Resíduos de bambu (Bambusa vulgaris) foram utilizados como matéria-prima para a produção de carvão ativado (CA). Os materiais foram coletados e transformados em CA mediante processos de carbonização (500°C, 1,67°C min-1, 60 min) e ativação (800°C, 10°C min-1, 60 min) com CO2 (100 mL min-1). O material obtido (CA CO2) foi caracterizado pelo seu rendimento, análise elementar, teor de cinzas, área superficial (SBET), método titulométrico de Boehm, microscopia eletrônica de varredura e utilizado como adsorvente para remoção dos contaminantes azul de metileno e fenol. Os modelos de isotermas de Langmuir e de Freundlich foram selecionados para entender o processo de adsorção. O CA CO2 produzido apresentou rendimento de 21,6%, teor de carbono de 82,13% e SBET de 856,78 m2 g-1, apresentando uma remoção rápida e elevada capacidade de adsorção para o azul de metileno (298,82 mg g-1) e fenol (558,29 mg g-1).

Abstract Bamboo (Bambusa vulgaris) wastes were used as raw material for producing activated carbon. The materials were collected and turned into activated carbons by carbonization (500 °C, 1.67 °C.min-1, 60 min) and activation (800 °C, 10 °C.min-1, 60 min) processes with CO2 (100 mL.min-1). The obtained material (CO2 AC) was characterized by its yield, elemental analysis, ash content, surface area (SBET), Boehm titration method, scanning electron microscopy and used as adsorbent for removing the methylene blue and phenol contaminants. The Langmuir and Freundlich isotherm models were selected for understanding the adsorption process. CO2 AC produced showed yield of 21.6%, carbon content of 82.13% and SBET of 856.78 m2.g-1, presenting rapid removal and high adsorption capacity for methylene blue (298.82 mg.g-1) and phenol (558.29 mg.g-1).

RESUMO A adubação balanceada é fator de importância comprovada na otimização do crescimento e produtividade das culturas. Objetivou-se avaliar o fluxo de biomassa e a eficiência de uso da chuva na palma forrageira cv. Gigante, adubada com combinações de doses de nitrogênio (10; 70; 100; 130 e 190 kg ha-1 ano-1 de N) e fósforo (10; 70; 100; 130 e 190 kg ha-1 ano-1 de P2O5), nas frequências de colheita anual e bianual, nas regiões de Quixadá e Tejuçuoca, no Ceará. Utilizou-se delineamento em blocos casualizados, em arranjo de parcelas subdivididas, com quatro repetições. Em Quixadá e Tejuçuoca, as combinações de N e P e frequências de colheita influenciaram as taxas de produções de diferentes ordens de cladódios e a eficiência de uso da chuva na palma forrageira. Em Quixadá, na colheita anual, verificou-se taxa de produção de forragem (TPF) de 10,3 kg ha-1 dia-1 na combinação N/P2O5 de 190,0/190,0 kg ha-1 ano-1 e na colheita bianual, observou-se máxima TPF de 4,6 kg ha-1 dia-1 na combinação N/P2O5 de 114,6/136,8 kg ha-1 ano-1. Em Tejuçuoca, na colheita anual, constatou-se máxima TPF de 30,0 kg ha-1 dia-1 na combinação N/P2O5 de 137,5/190,0 kg ha-1 ano-1 e na colheita bianual, registrou-se maior TPF de 38,0 kg ha-1 dia-1 na combinação N/P2O5 de 190,0/33,4 kg ha-1 ano-1. As taxas de produções de biomassa e eficiência de uso da chuva são otimizadas com o balanço de doses combinadas de nitrogênio e fósforo.

ABSTRACT Balanced fertilization is an important factor in optimizing the growth and productivity of crops. This study aimed to evaluate biomass flow and rain use efficiency in cactus pear cv. Gigante fertilized with combinations of nitrogen (10; 70; 100; 130 and 190 kg ha-1 year-1 N) and phosphorus (10; 70; 100; 130 and 190 kg ha-1 year-1 P2O5), in two harvest frequencies (annual and biennal), in the regions of Quixadá and Tejuçuoca, in Ceará. This was a split-plot randomized block design, with four replicates. In Quixadá and Tejuçuoca, the N and P combinations and harvest frequencies influenced the productions rates of different cladode orders and rain use efficiency in cactus pear. In Quixadá, in the annual harvest, the forage production rate (FPR) was 10.3 kg ha-1 day-1 in the N/P2O5 combination at 190.0/190.0 kg ha-1 year-1 and in the biennal harvest, the maximum FPR was 4.6 kg ha-1 day-1 in the N/P2O5 combination at 114.6/136.8 kg ha-1 year-1. In relation to the annual harvest in the municipality of Tejuçuoca, the maximum FPR was 30.0 kg ha-1 day-1 in the N/P2O5 combination at 137.5/190.0 kg ha-1 year-1 and in the biennal harvest, the maximum FPR observed was 38.0 kg ha-1 day-1 with the N/P2O5 combination of 190.0/33.4 kg ha-1 year-1. The biomass productions rate and rain use efficiency are optimized with the balance of combined levels of nitrogen and phosphorus.

ABSTRACT The present study evaluated the accumulation and export of nutrients in cactus pear (Opuntia ficus-indica) cv. Gigante, fertilized with combinations of nitrogen (10, 70, 100, 130, and 190 kg ha−1 year−1 N) and phosphorus (10, 70, 100, 130, and 190 kg ha−1 year−1 P2O5) under annual and biennial harvests, in Quixadá and Tejuçuoca, using a split-plot randomized block design with four replications. In Quixadá, under annual and biennial harvests, the following orders of accumulation of macronutrients (in kg ha−1 year−1) were found, respectively: K (98.8) > Ca (87.2) > N (46.7) > Mg (26.8) > S (18.4) > P (2.04) and Ca (33.5) > K (31.1) > S (18.6) > N (12.9) > Mg (10.5) > P (0.81). In Tejuçuoca, under annual and biennial harvests, the orders of accumulation of macronutrients were, respectively: K (146.5) > Ca (204.6) > N (128.1) > Mg (75.8) > S (50.3) > P (3.7) and K (397.2) > N (191.3) > S (241.2) > Ca (167.8) > Mg (131.0) > P (14.1). The maintenance/production fertilization in cactus pear should be planned according to productive potential, fertilization and harvest managements, and cultivation region, based on nutritional requirement and considering the nutrient recovery efficiency.

O objetivo do trabalho foi apresentar uma proposta de diferenciação das Regiões de Saúde no Brasil, baseada no desenvolvimento humano, contribuindo para a identificação de espaços geográficos comparáveis para observação, análise e acompanhamento do desempenho dos sistemas regionalizados de saúde. Os valores das dimensões do Índice de Desenvolvimento Humano Municipal foram calculados para as Regiões de Saúde pela agregação dos dados dos municípios, ponderados pelo seu tamanho populacional. O agrupamento das Regiões de Saúde em 5 grupos, segundo combinações de longevidade, riqueza e escolaridade, foi determinado pelo método K-Médias. Metade das Regiões de Saúde brasileiras foi classificada em grupos do tipo 1 e 2 e a outra metade em grupos dos tipos 3 a 5. A tipologia apresentada oferece um modelo de agrupamento de Regiões de Saúde homogêneas, coerente com os pressupostos teóricos do PROADESS. A opção por indicadores e métodos de agregação bem estabelecidos tende a favorecer a sua compreensão e utilização pelos atores ligados à gestão do Sistema Único de Saúde (SUS).

This article aimed to present a proposal for characterizing health regions in Brazil based on human development, contributing to the identification of comparable geographic areas for observation, analysis, and monitoring of performance in regionalized health systems. The dimensions of the Municipal Human Development Index were calculated for the health regions by aggregating data from municipalities, weighted by population size. The grouping of health regions in 5 groups, based on combinations of life expectancy, income, and schooling, was determined by the K-Means method. Approximately half of Brazil’s health regions were classified as type 1 and the other half as types 3 to 5. The typology provides a clustering model for homogeneous health regions, consistent with the theoretical assumptions of PROADESS. The choice of well-established indicators and aggregation methods tends to facilitate their comprehension and use by the actors involved in the administration of the Brazilian Unified National Health System (SUS).

Este trabajo presenta una propuesta para la diferenciación de las Regiones de Salud en Brasil, basado en el desarrollo humano, lo que contribuye a la identificación de áreas geográficas comparables para la observación, el análisis y el seguimiento del desempeño de los sistemas sanitarios regionalizados. Se calcularon los valores de las dimensiones del Índice de Desarrollo Humano Municipal para las Regiones de Salud, a partir de los datos municipales, ponderados por su tamaño poblacional. La clasificación de las Regiones de Salud en 5 grupos, de acuerdo a las combinaciones de longevidad, riqueza y educación, se determinó por el método K-medias. La mitad de las Regiones de Salud de Brasil fueron clasificadas como tipo 1 y grupo 2, y la otra mitad en grupos de dos tipos 3-5. La tipología presentada proporciona un modelo de agrupación de regiones sanitarias homogéneas, en consonancia con los supuestos teóricos de PROADESS. La elección de los indicadores y los métodos de agregación bien establecidos tienden a facilitar su comprensión y su utilización por los gestores del Sistema Único de Salud brasileño (SUS).

O objetivo do trabalho foi apresentar uma proposta de diferenciação das Regiões de Saúde no Brasil, baseada no desenvolvimento humano, contribuindo para a identificação de espaços geográficos comparáveis para observação, análise e acompanhamento do desempenho dos sistemas regionalizados de saúde. Os valores das dimensões do Índice de Desenvolvimento Humano Municipal foram calculados para as Regiões de Saúde pela agregação dos dados dos municípios, ponderados pelo seu tamanho populacional. O agrupamento das Regiões de Saúde em 5 grupos, segundo combinações de longevidade, riqueza e escolaridade, foi determinado pelo método K-Médias. Metade das Regiões de Saúde brasileiras foi classificada em grupos do tipo 1 e 2 e a outra metade em grupos dos tipos 3 a 5. A tipologia apresentada oferece um modelo de agrupamento de Regiões de Saúde homogêneas, coerente com os pressupostos teóricos do PROADESS. A opção por indicadores e métodos de agregação bem estabelecidos tende a favorecer a sua compreensão e utilização pelos atores ligados à gestão do Sistema Único de Saúde (SUS).

This article aimed to present a proposal for characterizing health regions in Brazil based on human development, contributing to the identification of comparable geographic areas for observation, analysis, and monitoring of performance in regionalized health systems. The dimensions of the Municipal Human Development Index were calculated for the health regions by aggregating data from municipalities, weighted by population size. The grouping of health regions in 5 groups, based on combinations of life expectancy, income, and schooling, was determined by the K-Means method. Approximately half of Brazil’s health regions were classified as type 1 and the other half as types 3 to 5. The typology provides a clustering model for homogeneous health regions, consistent with the theoretical assumptions of PROADESS. The choice of well-established indicators and aggregation methods tends to facilitate their comprehension and use by the actors involved in the administration of the Brazilian Unified National Health System (SUS).

Este trabajo presenta una propuesta para la diferenciación de las Regiones de Salud en Brasil, basado en el desarrollo humano, lo que contribuye a la identificación de áreas geográficas comparables para la observación, el análisis y el seguimiento del desempeño de los sistemas sanitarios regionalizados. Se calcularon los valores de las dimensiones del Índice de Desarrollo Humano Municipal para las Regiones de Salud, a partir de los datos municipales, ponderados por su tamaño poblacional. La clasificación de las Regiones de Salud en 5 grupos, de acuerdo a las combinaciones de longevidad, riqueza y educación, se determinó por el método K-medias. La mitad de las Regiones de Salud de Brasil fueron clasificadas como tipo 1 y grupo 2, y la otra mitad en grupos de dos tipos 3-5. La tipología presentada proporciona un modelo de agrupación de regiones sanitarias homogéneas, en consonancia con los supuestos teóricos de PROADESS. La elección de los indicadores y los métodos de agregación bien establecidos tienden a facilitar su comprensión y su utilización por los gestores del Sistema Único de Salud brasileño (SUS).

A produção de biomassa em uma pastagem pode ser incrementada com o uso de fertilizantes, principalmente os nitrogenados. Diante disso, objetivou-se, com este trabalho, avaliar o fluxo de biomassa do capim-massai, durante o estabelecimento e a rebrotação, em casa de vegetação, sob cinco doses de nitrogênio (0; 150; 300; 450 e 600 mg de N dm-3 de solo), em delineamento inteiramente casualizado, com medidas repetidas no tempo, e cinco repetições. A taxa de alongamento foliar foi incrementada pelas doses de nitrogênio (N) e o crescimento de estabelecimento apresentou maior valor, em relação ao das rebrotações. A taxa de alongamento das hastes não foi influenciada pelas doses de N. O crescimento de estabelecimento apresentou maior valor para esta variável, em relação ao das rebrotações. A taxa de senescência foliar anterior não sofreu influência das doses de N, porém, foi alterada entre os ciclos de crescimento. O número de folhas vivas por perfilho foi superior, para as maiores doses e no estabelecimento, o inverso ocorrendo para o filocrono. A dose aplicada de 600 mg dm-3 de N proporcionou um incremento de 448%, na taxa de produção de forragem, e de 455%, na taxa de acúmulo de forragem, em relação àquelas do manejo sem N. A adubação nitrogenada proporciona respostas positivas nas variáveis do fluxo de biomassa do capim-massai.

The use of fertilizers, especially nitrogen, can increase significantly the biomass production of a pasture. The objective of this study was to evaluate the biomass flow of Massai grass produced in greenhouse during the establishment and regrowth under five nitrogen fertilization levels. The experiment was arranged in a completely randomized split-plot design with five nitrogen levels (0; 150; 300; 450 e 600 mg de N dm-3 of soil) and five replications (plots) .The leaf elongation rate was increased with the nitrogen fertilization levels and the establishment growth presented higher values in relation to the regrowth. The culm elongation rate was not influenced by N levels. The establishment growth presented higher values than regrowth. The leaf senescence rate before the cut was not influenced by the nitrogen fertilization, however it was altered by the growth cycles. The number of living leaves per tiller was superior on plants fertilized with highest N levels and at establishment growth, however an opposite effect was observed to the phylochron. The fertilization level 600 mg de N dm-3 of soil lead to an increase of 448% on herbage growth, and of 455% on herbage accumulation rates in relation to the 0 mg de N dm-3 of soil. The nitrogen fertilization provides positive responses to the biomass flow of Massai grass.

The objective of this study was to identify the pattern of deposition of feces by supplemented crossbred dairy cows after the lactation peak on cultivated areas under levels of intensification of the system and its effects on nitrogen cycling, with the aid of geostatistics, in the rainy period. Treatments were composed of two levels of nitrogen fertilization (equivalent to 400 and 800 kg N/ha/year) and two types of animals, according to the daily milk production. Geostatistical and descriptive analyses of the data were conducted. The data presented positive coefficients of skewness and platykurtic kurtosis. For the coefficient of variation, there was elevated alteration, with rest areas showing higher values and paddocks with a higher level of fertilization showing lower values.The climate factors radiation, temperature and relative humidity significantly influenced the dispersion and location of feces. As to the degree of spatial dependence, the classification varied from moderated to strong. The range was from 14.0 to 12.7 m for the rest areas and paddocks, respectively. Fertilization and concentrate supply affected the deposition and loss of nitrogen via feces, elevating its values as the nutritional uptake is elevated. Fecal deposition showed heterogeneity, with areas of greater concentration such as shades, entrance of the paddocks and threshing floor, showing deposition peaks that reach 1,051.2 kg N/ha/year.

This study evaluated the biomass flow of massai grass in regrowth subjected to different nitrogen levels (control - no fertilization; 400; 800; and 1200 N kg ha-1year-1) and under rotational stocking with sheep, in a completely randomized design with repeated measures over time. The leaf elongation rate increased with increasing nitrogen levels (N) and the fourth grazing cycle presented a lower value compared with the others. The stem elongation rate responded linearly with increasing levels of N, but it was not influenced by grazing cycles. The senescence rate of leaves remaining before grazing and after grazing were not influenced by the nitrogen fertilization or amended with successive grazing cycles. The phyllochron was influenced only by the nitrogen fertilization, with a decreasing linear response with nitrogen levels. Quadratic response was observed for the average length of leaves with increasing N levels and the grazing cycle 4 presented the lowest value for this variable. For each kilogram N ha-1 year-1, increases of 0.161 and 0.1604 kg ha-1 day-1 were verified in the herbage growth and accumulation rates, respectively. Nitrogen fertilization favors the biomass flow of massai grass, promoting an expressive increase in the production and accumulation of forage.

This study aimed to evaluate the growth index of massai grass during two regrowth cycles in a greenhouse under five levels of nitrogen (0, 150, 300, 450 and 600 mg N/dm³ of soil) and eight growth ages (5, 8, 11, 14, 17, 20, 23 and 26 days) in a split-plot design with five replications. The following variables were evaluated: net assimilation rate, herbage growth rate, relative growth rate, leaf area ratio, leaf weight ratio and specific leaf area. The effect of nitrogen was detected on the variables net assimilation rate (regrowths 1 and 2), leaf area ratio (regrowth 1), leaf weight ratio (regrowths 1 and 2), specific leaf area (regrowths 1 and 2) and herbage growth rate (regrowths 1 and 2). The growth ages influenced the relative growth rate (regrowth 2) and the net assimilation rate (regrowth 2). The net assimilation rate presented linear effect, estimated in 0.70 and 2.86 g/m² leaf.day-1 for the 0 and 600 mg N/dm³ soil, respectively (regrowth 1). For each milligram of N/dm³ added, the leaf area ratio was reduced in 0.0000258 m² leaf/g plant (regrowth 1). The herbage growth rate was estimated in 1.38 and 37.02 g/m².day-1 (regrowth 1), and 4.37 and 32.20 g/m².day-1 (regrowth 2) for the 0 and 600 mg N/dm³ soil, respectively. The massai grass' growth is favored by nitrogen fertilization, and little do the growth ages affect the growth index of the plants.

The objective of this study was to evaluate gas exchange in the massai grass during establishment and regrowth cycles in a greenhouse, using five nitrogen (N) fertilization levels. A completely randomized split-plot design of five nitrogen levels (0; 150; 300; 450 and 600 mg N•dm-3 of soil) was employed with the N levels as plots, and the cycles (establishment, regrowth 1 and 2) as subplots, evaluated with five replicates. We evaluated leaf transpiration (E), leaf temperature (TFOL), leaf photosynthesis rate (A), leaf carbon dioxide concentration (Ci), stomatal conductance (gs), photosynthesis/transpiration ratio (A/E), photosynthesis/conductance ratio (A/gs), chlorophyll relative index (CRI), and nitrogen sufficiency index (NSI). Growth cycles influenced all physiological characteristics, except for NSI. N fertilization levels affected TFOL, A, CRI and NSI variables, whereas for gs, E, Ci, A/E and A/gs it did not occur. A increased from 6.38 to 10.33 µmol•m-2.s-1, at levels 0 and 600 mg N•dm-3 of soil, respectively. Gas exchange in the massai grass was favored by nitrogen fertilization, since the cycles amended these characteristics of the grass.

To evaluate biomass components of Massai grass under five doses of N (0, 150, 300, 450 and 600 mg N/dm³ soil) during three cycles of growth (establishment, regrowth 1 and regrowth 2) this study was carried out. The experiment was carried out in a greenhouse, in a completely randomized design with measures repeted over time and five replications. In the three cycles, nitrogen doses had increasing linear effect on green herbage dry matter (GHDM), green leaf dry matter (GLDM), on the tiller population density (TPD) and on forage density. Canopy height and foliage height were the highest ones in establishment of regrowth 2, respectively, and they decreased at the highest doses of nitrogen. Irrigation depth was the greatest at the highest doses and in regrowth 1. Water use efficiency responded positively to the doses, being the regrowth 2 the highest values were obtained at the highest doses of nitrogen. Nitrogen use efficiency by Massai grass is influenced by fertilizantion as well as by the cycles. Nitrogen fertilization has positive effects on the components of Massai grass biomass.

Objetivou-se avaliar os componentes da biomassa do resíduo pós-corte em capim-massai submetido a cinco doses de nitrogênio (0; 150; 300; 450 e 600 mg N dm-3 de solo) num delineamento inteiramente casualizado, com cinco repetições (vasos) em casa de vegetação. Avaliaram-se a altura residual, a densidade populacional de perfilhos (DPP), a massa seca de forragem total residual (MSFTr), de forragem verde residual (MSFVr), de forragem morta residual (MSFMr), de lâmina foliar verde residual (MSLVr), de colmo verde residual (MSCVr), relação lâmina foliar/haste (LF/C), a massa seca radicular (MS radicular) e a relação parte aérea/raiz. Observou-se efeito quadrático dos níveis de adubação nitrogenada sobre a altura residual. As variáveis MSFTr, MSFVr e MSCVr responderam positivamente, enquanto a MSLVr revelou comportamento quadrático com os níveis de N. Constatou-se valores estimados de 13,35 e 39,73 g MS/vaso para MSFTr, de 9,71 e 24,69 g MS/vaso para MSFVr e de 3,65 e 15,07 g MS/vaso para MSFMr nas doses de 0 a 600 mg N dm-3 de solo, respectivamente. A MS radicular respondeu positivamente às doses de N. A adubação nitrogenada proporciona resultados positivos sobre as características estruturais do resíduo pós-corte do capim-massai.

After cut residue of Massai grass under five nitrogen fertilized levels were evaluated. A completely randomized design with five nitrogen levels (0; 150; 300; 450 and 600 mg N dm-3 of soil) and five replicates (plots) in greenhouse was used. It was evaluated the residual canopy height (RCH), the tiller population density (TPD), the total residual forage dry mass (TFDM), the residual green forage dry mass (GFDM), the senescent forage dry mass (SFDM), the residual green leaf dry mass (GLDM), the residual green culm dry mass (GCDM), leaf/culm ratio (L/C), root dry mass (RDM) and above ground/root ratio (A/R). There was square effect of nitrogen fertilization on RCH. There were crescent and linear effect of nitrogen fertilization on TFDM, GFDM and GCDM. There was square effect of nitrogen fertilization on GLDM. The values were estimated in 13.35 and 39.73 g DM/plot to TFDM; 9.71 and 24.69 g DM/plot to GFDM and 3.65 and 15.07 g DM/plot to SFDM on 0 and 600 mg N dm-3 of soil, respectively. The RDM presented positively response to the N levels. It was concluded that the nitrogen fertilizing brought benefits for all structural characteristics after cut of Massai grass.