Objetivou-se avaliar o índice vegetativo da diferença normalizada (NDVI) do dossel da Urochloa brizantha cv. Marandu em função das doses de nitrogênio, com o uso de câmera multiespectral e sensor óptico ativo. Além disso, realizou-se estudo de correlação entre o NDVI, obtido pela câmera e o sensor óptico, e a características produtivas do capim Marandu. Os tratamentos foram compostos por cinco doses de nitrogênio (N) correspondentes a 0; 62,50; 125; 187;40; e 250 mg dm-3. Antes da semeadura, aplicou-se 2250 mg dm-3 de calcário dolomítico. Foram aplicados 200 mg dm-3 de fósforo (P2O5) no plantio e 300 mg dm-3 de potássio (K2O). As predicações das equações de regressão indicam que as respostas espectrais do dossel da planta forrageira foram influenciadas pela aplicação de N. Em todas as situações os valores de NDVI adquiridos pelo sensor óptico ativo se ajustaram a modelos matemáticos de regressão de segundo grau, e os da câmera multiespectral, apenas aos 42 dias de crescimento após a adubação, ajustaram-se ao modelo linear. Assim, a câmera digital convertida e o sensor óptico ativo detectaram mudanças na reflectância espectral do dossel da cultivar Marandu em reposta à adubação nitrogenada.

Studies carried out with the use of gliricidia biomass found that green manure contributes to increasing the productivity of forest crops when compared to the incorporation of other legumes. This study aimed to evaluate the viability of vegetative propagation by cuttings in the development of rooting and budding of Glyicidium sepium in different concentrations of indolebutyric acid (IBA). The experiment was carried out in a greenhouse with an entirely randomized block design and increasing concentrations of IBA 0, 625, 1250, and 3000 mg.L-1 with six replicates. The cuttings were standardized in length and diameter, then treated with sodium hypochlorite and immersed in different concentrations of IBA. The parameters plant evaluated were the sprouts number, sprouts length, sprouts diameter, sprouts dry weight, and roots dry weight. The concentration of IBA was shown to be effective in increasing all parameters studied at the IBA concentration of 2100 mg.L-1, and the higher concentrations did not offer any cost-benefit advantages for the production of gliricidia by cutting.

Eucalyptus planting represents 72.7% of the total area of planted trees in Brazil, and is constantly growing in the Cerrado biome. Thus, the present study aimed to evaluate the physical qualities of soil under Eucalyptus sp. and a fragment of cerrado sensu stricto. The study was conducted at the experimental farm of the Federal University of Tocantins, campus Gurupi, TO, on the coordinates 11º 46’ 25’’ latitude S and 49º 02’ 54’’ longitude W, in soil classified as Plinthosol petric. The collections were performed in the layer with a depth of 0–20 cm, with eleven repetitions for each area. The attributes evaluated were: soil texture, density (DS), particle density (PD) and total porosity (TP). The soil granulometric composition in the two studied areas was predominant of the sandy fraction. The values of DS, PD and TP did not show significant differences by Tukey test (5%), which assumes that the change of cover from cerrado sensu stricto to forest planted with Eucalyptus sp. does not favor physical problems for the soil under study.

Pasture management studies seldom use remote sensing, especially for Andropogon gayanus cv. Planaltina. This work aimed to investigate whether a single-chip digital camera converted into multispectral equipment could measure and perceive differences in the normalized difference vegetation index (NDVI) in Andropogon gayanus cv. Planaltina grass subjected to different doses of nitrogen. In a greenhouse with a randomized block design, the research team subjected the cultivar to 5 different doses of nitrogen (treatments), with four replications. The group compared the NDVI measurements of canopies carried out with a GreenSeeker® HCS-100 active optical sensor and a Canon PowerShot A495 single-chip camera that was converted into a multispectral device by replacing the glass filter that blocks the passage of the infrared by a filter that allows the passage of the red and near infrared wavelengths. Both measurements were correlated with nitrogen doses, stem and leaf blades dry matter and dead material production, and cultivar height. The study concluded that the multispectral camera, as well as the active optical sensor, measured the NDVI and noticed differences in the production of stem, leaf blades and dead material dry matter, and Andropogon gayanus cv. Planaltina plant height when subjected to different doses of nitrogen.

The guava tree is the fruit of the guava tree of the species Psidium guajava L. belonging to the family of Myrtaceae a rustic fruit and adapts to the most varied types of soils. It is a fleshy fruit, thin-skinned, green, or when mature yellowish and very rich in soluble fibers. Seed germination is influenced by factors such as substrate, which can improve germination, resulting in the acquisition of more vigorous seedlings. The experiment was conducted in a greenhouse at the Federal Institute of Education, Science and Technology of Tocantins, Gurupi/TO, in 2017. The seeds of guava Kumagai and Paluma (Psidium guajava L.) used in the experiment were taken directly from the fruit, which was collected in the urban region of Gurupi in March 2017. For the two varieties evaluated, both for the first emergence count and seedling emergence, the substrates stood out: organic compound + black earth + commercial substrate (55% and 37%) (67% and 49%), washed sand + rice straw + black earth (52% and 36%) (52% and 36 %) lower substrates: washed sand (46% and 10%) (66% and 35%) and rice straw + sawdust + black ground (47% and 7%) (59% and 31%), respectively. The substrates: organic compound + black earth + commercial substrate and washed sand + rice straw + black earth provided the highest values of viability and vigour in white and red pulp guava seeds.

Through sustainable agriculture it is possible to explore the coffee culture in consortium with native forests in more rugged reliefs, as coffee is a permanent crop in addition to the climatic conditions offered by the swamps that favor its development. Given the above, the present work proposes, based on the acidity results, to quantify  the need for correctives in the soil to obtain a better nutritional use offered by agroforestry cultivation of organic coffee in the shade with favorable results to increase productivity and, consequently, the farmer's profit. The research was carried out at the Várzea da Onça farm, in the Yaguara Ecological Complex, located in the municipality of Taquaritinga do Norte, Borborema plateau, in the Agreste Pernambuco mesoregion. Altitude, it is necessary to adopt appropriate management techniques that guarantee production, soil conservation and biodiversity, proposing soil correction to guarantee the ideal nutritional conditions for coffee growth. For this purpose, soil samples were collected in the Top (T), Hillside (E) and Pedimento (P) ranges at depths of 0-20, 20-40 and 40-60 cm when planting shaded coffee and soil samples from Native Forest (MN) preserved and legally protected from the Brejo de Taquaritinga. Active, exchangeable and potential acidity were analyzed, as well as the sum of bases, the potential and effective cation exchange capacity, base saturation and aluminum saturation. The results obtained were subjected to analysis of variance and the means were tested at 5% by the Tukey test. A potential of the system was found with low to very low natural fertility, with a strongly acidic reaction. Thus, adequate soil management and correction techniques are necessary for the crop to absorb all the nutrients made available by the organic matter present on the surface, concluding that all slopes require liming, the slope of Hillside and Mata Nativa they also need plastering for the culture to develop properly.

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Atividades antrópicas têm causado a elevação da concentração dos gases de efeito estufa na atmosfera, principalmente devido mudanças causadas no uso da terra, que alteram a capacidade dos solos em armazenar o CO2. O presente estudo busca revisar publicações atuais sobre mudanças no estoque de carbono do solo sob diferentes coberturas vegetais publicados nos últimos anos e realizar uma avaliação crítica e sistêmica do assunto, considerando as metodologias utilizadas em cada trabalho e os diferentes tipos de manejo e uso dos solos em várias regiões do Brasil. Para a coleta de dados foram selecionados 35 artigos publicados nos últimos dez anos que se correlacionavam com o tema. Feito o levantamento dos artigos buscou-se caracterizar os ecossistemas brasileiros e resumir os principais dados publicados sobre os estoques de carbono nos ecossistemas e posteriormente os as estimativas dos estoques em ambientes sob mudança uso do solo. Os resultados apontaram que as diferentes coberturas vegetais apresentam distintas, entretanto positiva capacidade em estocar carbono no solo no Brasil e que variáveis como o manejo, a textura, atributos físicos, químicos e biológicos são fatores significativos e podem e influenciam diretamente nos resultados.