INFLUENCE OF Urochloa brizantha ON THE GROWTH AND NUTRITIONAL ABSORPTION OF TREE SPECIES

Influence of Urochloa brizantha on the growth and nutritional absorption of tree species. The objective of this study was to evaluate the influence of Urochloa brizantha var. Marandu on the growth and accumulation of macronutrients in the leaves of Cordia trichotoma and Guarea guidonia. Seedlings of tree species were transplanted to 18-liter pots and kept free of U. brizantha for three months. After that period, three treatments were adopted that consisted of the control (T0), two plants of U. brizantha per pot (T2) and four plants of U. brizantha per pot (T4). Growth and nutrient accumulation of tree species were evaluated after 84 days of coexistence with U. brizantha. The increment in diameter, of both tree species, leaf area and shoot dry matter of G. guidonia were significantly affected by the presence of U. brizantha, compared to the control. Significant differences were observed for the accumulation of potassium and magnesium in the leaves of C. trichotoma.

Weed interference factors that affect the growth of an atlantic forest tree species

The objective of this study was to assess the possible existence of allelopathy and competition for water and nutrients of the grass Urochloa brizantha (Hochst. ex A. Rich.) Stapf cv. Marandu grown together with Schinus terebinthifolius Raddi in a greenhouse. The experimental design was completely randomized in a factorial scheme with 3 factors and the following levels: (1) one individual of the forest species with and without the presence of U. brizantha at a density of 4 individuals per pot; (2) supply of nutrients in limiting or non-limiting dose; and (3) supply of a limiting or non-limiting amount of water. We measured the height and root collar diameter of the tree seedlings, as well as the shoot and root dry weights of both species. There was competition by the grass with the tree species. The coexistence reduced the height by 30.5 cm, the root collar diameter by 1.58 mm and the shoot and root dry weights by 22.7 g and 9.5 g, respectively, of S. terebinthifolius. The greater supply of water in the pots increased the height by 18.9 cm of the S. terebinthifolius seedlings compared to the plants grown with limited water supply. Evidence was also observed of competition for nutrients, principally at the largest nutrient addition level, where the presence of the grass caused an additional decrease in the root collar diameter and shoot dry weight of the tree species, while the shoot and root dry weights of the grass increased. The results did not allow evaluating the existence of allelopathy of U. brizantha on S. terebinthifolius. terebinthifolius

CORRELATION BETWEEN THE CARDIORESPIRATORY FITNESS LEVEL AND HABITUAL PHYSICAL ACTIVITY IN BRAZILIAN AIR FORCE RECRUITS

Cardiorespiratory fitness is the ability to maintain moderate or high-intensity efforts for long periods of time and is highly related to physical activity habits and fitness levels. Analyzing habitual physical activity in military personnel and its relationship with cardiorespiratory fitness is consequently fundamental. Thus, the objective of this study was to verify the correlation between the cardiorespiratory fitness level and habitual physical activity in Brazilian Air Force recruits. The sample consisted of 86 recruits in the final phase of the soldier training course. Data was collected using the 12-minute cardiorespiratory fitness test and the Baecke questionnaire validated for the Portuguese language to assess the practice of habitual physical activity. Descriptive statistics were used for sample characterization and exploratory analysis. The distribution of data normality was analyzed using the Shapiro-Wilk test, followed by Pearson’s correlation test and the Mann-Whitney U test to compare the groups with lower and higher cardiorespiratory fitness. The significance level of p ≤ 0.05 was adopted. According to the results, 63.9% of the sample had satisfactory cardiorespiratory fitness levels (good and excellent). No significant correlations were observed between cardiorespiratory fitness and habitual physical activity indices, except for the physical exercise/sports index (p= 0.05). It was found that only the Body Mass Index showed a difference (p= 0.017, Effect Size= 0.637) between the cardiorespiratory fitness groups. It is concluded that most military recruits have adequate cardiorespiratory fitness levels, but these are not influenced by the habitual practice of physical activity.  Article visualizations

O uso de sistemas agroflorestais diversificados na restauração florestal na Mata Atlântica

The Brazilian new environmental law permits the use of agroforestry systems to restore degraded areas protected by legislation, especially in small farms. One question that arises is if it is possible to reduce costs of the restoration process with these agroforestry systems and, at the same time, to offer ecological services, similar to afforestation with the exclusive use of native species of the Atlantic Forest biome. Seeking results to proof the effectivity, an agroforestry system established in 2005, at Seropédica, RJ state, with the objective of connecting two forest fragments, went through a series of evaluations realized on the ecological effectiveness on the connection of these fragments. The results indicated that the quantity and quality of soil fauna and mycorrhizal fungi obtained benefits by the agroforestry system in comparison to the pasture matrix, but are still at lower levels than the forest fragments. Pasture near the agroforestry system has benefited from the environmental improvement there, originated from a “positive edge effect”, a situation quite different from the pasture that was farther from the area of influence of the agroforestry corridor. For the indicators used, the agroforestry system was eficient.Com a nova legislação ambiental brasileira vislumbra-se a possibilidade do uso de sistemas agroflorestais diversificados para recompor áreas de preservação permanente e reserva legal, principalmente em pequenas propriedades rurais. Uma pergunta que surge, diz respeito a capacidade desses sistemas em reduzir custos na restauração florestal e ao mesmo tempo apresentar eficiência ecológica similar aos plantios em que se faz uso exclusivo de espécies nativas do bioma em questão. Buscando a resposta avaliou-se nesse estudo um sistema agroflorestal implantado em 2005, em Seropédica, RJ, que tinha o objetivo de interligar dois fragmentos florestais ali existentes. Desde então foram feitas uma série de avaliações sobre a eficácia ecológica desse “corredor agroflorestal” na interligação desses fragmentos. Os resultados indicaram que a quantidade e a qualidade da fauna do solo e fungos micorrízicos foram favorecidos pelo sistema agroflorestal em comparação à matriz de pastagem, mas ainda se encontram em níveis inferiores aos fragmentos florestais interligados. A pastagem próxima ao sistema agroflorestal vem se beneficiando da melhoria ambiental ali existente, criando um “efeito de borda positivo”, situação bem distinta da pastagem que se encontrava mais distante da área de influência do corredor agroflorestal. Para os indicadores utilizados, o sistema agroflorestal foi eficiente.

Estratégias de controle de braquiárias Urochloa spp. na formação de povoamento para restauração florestal

Forest restoration in pastures dominated by Urochloa spp. (brachiaria) shows relatively high cost, mainly by the difficulty of controlling this weed. The objective of this work was to determine the most efficient brachyria control for forest restoration formation. Four different strategies for brachiaria control in the forest restoration area were compared in the city of Bom Jardim, Rio de Janeiro state: T1 weeding in strips in the planting lines and mowed between the lines; T2 weeding in strips in the planting lines and applications of glyphosate (1.44 kg i.a. ha-1) between the lines; T3 - weeding in total area and consortium with herbaceous legumes nitrogen-fixing; T4 - weeding in strips in the planting lines, mowing and consortium with eucalyptus between the lines. The growth in height, the diameter at ground level and the diameter of the top of ten forest species at different ages were evaluated, as well as all costs involved in the application and maintenance of each treatment, up to 30 months after planting. In every age of valuation, forest plants showed significantly higher average growth in height and diameter at the ground level in the treatment of consortium with herbaceous legumes and application of glyphosate. At 24 months after planting, the top of the trees that were introduced had already covered 80% to 90% of the area of   experimental unit that received the T3 (legumes) and T2 (Glyphosate) treatments, respectively. However, the maintenance cost of the T3 was almost double the T1 units and the cost of the latter was almost three times higher than the units analyzed for T2. As a general rule, eucalyptus consortium between the lines of planting did not harm, but also did not benefit the growth of the native species planted up to 30 months after planting. Chemical control and consortium with herbaceous legumes can be pointed as effective alternatives to control the brachiaria of this area, anticipating the formation of stands and resulting in resource savings.A restauração florestal em áreas de pastagens, dominadas por Urochloa spp. (braquiárias), apresenta custo relativamente elevado, principalmente pela dificuldade de controle dessa planta infestante. O objetivo deste trabalho foi determinar a forma de controle de braquiárias mais eficiente para a formação de povoamento para restauração florestal. Foram comparadas quatro estratégias para controle de braquiária em área de restauração florestal no município de Bom Jardim - RJ: T1 - capina em faixas nas linhas de plantio e roçadas nas entrelinhas; T2 - capina em faixas nas linhas de plantio e aplicações do herbicida glyphosate (1,44 kg i.a. ha-1) nas entrelinhas; T3 - capina em área total e consórcio com leguminosas herbáceas fixadoras de nitrogênio; T4 - capina em faixas nas linhas de plantio, roçadas e consórcio com eucalipto nas entrelinhas. Avaliou-se o crescimento em altura, diâmetro no nível do solo e diâmetro de copa de dez espécies arbóreas em diferentes idades, bem como todos os custos envolvidos na aplicação e manutenção de cada tratamento, até 30 meses após o plantio. Em todas as épocas de avaliação, as plantas florestais apresentaram média de crescimento significativamente superior em altura e em diâmetro nos tratamentos de consórcio com leguminosas e aplicação de glyphosate (T3 e T2). Aos 24 meses após o plantio, a copa das árvores implantadas já recobria 80% a 90% da área da unidade experimental nesses tratamentos. Entretanto, o custo de manutenção do T3 foi quase o dobro das unidades de T1 e o custo deste último foi quase três vezes superior das unidades submetidas a T2. O consórcio de eucalipto nas entrelinhas de plantio não prejudicou, mas não beneficiou o crescimento das espécies nativas. O controle químico e o consórcio com leguminosas herbáceas podem ser apontados como alternativas eficazes para controle da braquiária dessa área, antecipando a formação dos povoamentos e resultando em economia de recursos

Diurnal ingestion behavior of crossbred heifers in a sylvanpastoral system in a tropical region

Knowledge of the ingestive habits of animals enables better adjustment of their management, resulting in enhanced production. The objective of this research was to compare the effects of two pastoral systems (sylvanpastoral and monocultural) in Brachiaria brizantha cv. Marandu forage, two seasons of the year (rainy summer and dry winter), and two diurnal periods (morning and afternoon). Five parameters of diurnal behavior were observed (grazing, standing rumination, decumbent rumination, standing at rest, and decumbent rest) in ¾ Holstein-Zebu heifers. The results showed that grazing and rumination and rest while standing were more frequent during the dry season; grazing of the Marandu grass was more frequently observed under the sylvanpastoral system compared to the monoculture pasture without shade, whereas the opposite was true of rumination and rest while standing; finally standing and decumbent rumination were more frequent in the afternoon than in the morning. The sylvanpastoral system and the dry season promoted more frequent grazing and also better quality of the grass forage, while improving the thermal comfort of the animals, which are positive effects from the standpoint of livestock production and pasture sustainability

Evaluation of thermal comfort in a silvipastoral system in a tropical environment

The use of trees in silvipastoral systems can improve quality of the microclimate and thermal comfort of animals. The object of this research was to compare differences in microclimatic conditions in three environments (under the canopy of trees of the species Acacia holosericea, in the space between rows of trees and in full sunlight in monoculture grass) of a sylvopastoral system, at three hours of the day (9:00, 12:00, and 15:00), in two seasons of the year (dry = winter and wet = summer), in the municipality of Seropédica, RJ. The statistical design was randomized complete blocks in which environment represented the main plots and hour of day and season of year were split plots, with four replications. The nine microclimatic variables studied were: black globe temperature (bgt), dry bulb temperature (dbt), humid bulb temperature (hbt), maximum daily temperature (MaxT), minimum temperature (MinT), air velocity (av), temperature humidity index (THI), black globe humidity index (BGHI), and radiant thermal load (RTL). Results showed that the values of bgt, hbt, THI, and BGHI were lower in the dry than the wet season. BGHI was lower in the morning and afternoon than at noon, correlated with THI (r = 0.85) and was shown to be more precise than the latter as an indicator of thermal comfort. The tree canopy reduced the heat load that the animal would feel by 26% compared with the full sunlight environment

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio