The great solar radiation in the Brazilian semiarid region, combined with an adequate irrigation management, favors fruit production and quality of crops that were adapted to this region. The objective of this work was to evaluate the fruit quality of two apple cultivars grown in the Sub-Mid São Francisco River Valley under different irrigation water depths. A complete randomized block experimental design in a split -plot arrangement with five replications was used. The plots consisted of four irrigation water depths (ID) (60, 80, 100 and 120% of the reference evapotranspiration - ETo), the subplots consisted of two apple cultivars (C) (Julieta and Princesa) and the sub-subplots consisted of fruit positions in the tree canopies (FP) (east and west sides). The soluble solids content (SS), titratable acidity (TA), SS/TA ratio, pulp firmness (PF) and fresh weight (FW) of the fruits were evaluated. The factors evaluated showed no triple interaction between the evaluated factors, however, the SS and TA were significantly affected by them; the interaction between ID and C significantly affected the PF; the interaction between ID and FP significantly affected the PF, SS/TA ratio and FW; and the interaction between C and FP significantly affected the SS/TA ratio. The increase in water depth increased the fruit size of both cultivars, without compromising the post-harvest quality. The cultivar Princesa presented the best results regarding SS, TA, PF and FW, however, both cultivars had organoleptic characteristics within the recommended standards for commercialization. The fruits harvested on the west side presented better post-harvest quality.

Cassava wastewater is the liquid residue of the cassava flour processing and its application to the soil as fertilizer for agricultural crops is a good alternative to sources of nutrients for plants. In this context, the objective of this work was to evaluate the growth and seed yield of sunflower on soil fertilized with cassava wastewater. A randomized block experimental design with four replications was used, with six cassava wastewater rates (0, 8.5, 17, 34, 68 and 136 m3 ha-1) and six plant sampling times (15, 30, 45, 60, 75 and 90 days after sowing), using the sunflower cultivar Helio-250. The evaluated variables were total leaf area, leaf area index, leaf area ratio, specific leaf area, leaf weight ratio, shoot dry mass and sunflower seed yield. The use of cassava wastewater rate of 136 m3 ha-1 increases the seed yield, leaf area, leaf area index and shoot dry mass, and results in lower leaf area ratio, specific leaf area and leaf weight ratio of sunflower (cv. Helio-250) crops.

The objective of this work was to evaluated the precipitation characteristics (depth, I30 and erosivity) and their effects on sediment production in three watersheds under different managements of land use 35 - year regenerating Caatinga (RC), thinned Caatinga (TC), which underwent thinning of trees with diameter smaller than 10 cm; and deforested Caatinga (followed by burning and pasture) (DC). The experimente was conducted in the central, tropical semiarid region of the State of Ceará, Brazil. The precipitation events, surface runoff and sediment production were monitored from 2010 to 2015. The precipitation characteristics were subjected to Pearson's correlation at 1 and 5% of significance and the events that produced sediments in each watershed were hierarchically grouped by hierarchical cluster analysis technique. Two hundred precipitation events were recorded, with 23 (RC), 18 (TC) and 43 (DC) events producing sediments. The use of thinning (TC) decreased the sediment production by 53.5%, while the deforestation, burn and pasture cultivation (DC) increased soil losses by 14%, compared with the RC. The sediment production was greatly correlated with the I30 in the three watersheds, denoting the erosion process great dependence on the precipitation intensity.

Mangabeira fruits are collected from native populations under anthropic pressure. It is therefore essential to obtain morphogenetic information to genetically improve populations, thereby preventing genetic erosion. This research was carried out in the state Amapá and aimed to verify the morphological dissimilarity between two populations, one composed of 36 native progenies and one of eight progenies from Paraiba, outlined in lattices with two replications and six plants per part. The evaluated characteristics were: agronomic value (VA), treetop circumference (CCP), plant height (ALP), estimated number of fruits per plant (NEF), fruit color (COF), average weight of 10 fruits (PMF), fruit diameter (DF), average pulp weight of ten fruits (PMP), average length of 10 fruits (CMF), average number of seeds of 10 fruits (NMS). Our results indicate that the phenotype was mainly determined by responses to environmental changes; in the correlations, inherent fruit characteristics (weight, size, and color) did not affect the VA, while biometric characters influenced VA values. Higher plants presented larger fruits and a larger diameter, bigger quantities, there is also apparent contrast, with a larger amount of smaller size; the populations are dissimilar, indicating the possibility of obtaining of diverging superior segregating.

The common bean requires high levels of nitrogen (N) to achieve high productivity, which can be supplied, at least partially, by the biological nitrogen fixation (BFN). Two field experiments were carried out in the winter season of 2015 aiming to evaluate the effects of different cover crops, desiccation times and the agronomic performance of the common bean inoculated with rhizobia. The experiments were assembled in a randomized block design with four replications, in a factorial split-plot arrangement with two additional treatments (5x4x2+2). The factors were composed of five cover crops, four desiccation times, two seed inoculation treatments and two additional controls (TN = 90 Kg N ha-1 and T0 = without N and without inoculation). The variables analyzed in the cover crops were dry mass (DM) and total nitrogen (Total-N). With the common bean, the chlorophyll content (CC), the number of nodules (NN), the nodule dry weight (NDW), the shoot dry weight (SDW), the root dry weight (RDW) and the grain yield (GY) were evaluated. The results showed that the agronomic performance of the common bean was not affected by the desiccation times of the cover crops, although the amount of Total-N accumulated by cover crops was influenced by sowing times. Inoculation of the common bean promoted an increase in the NN, NDW, CC and SDW. Higher GY of the common bean was achieved with its cropping after Brachiaria brizantha, Brachiaria ruziziensis, millet and fallow.

Wood, in general, is a material with excellent properties; however, some features may limit its use. In this sense, various thermal treatments are emerging as alternatives to improve the technological properties of wood. In this context, this study aims at analyzing the effects of time and temperature (hydrothermal treatment and freezing) on the physical and mechanical properties of Eucalyptus grandis W. Hill ex Maiden. Three trees were selected, and only the heartwood was used to obtain the test body dimensions of 30 × 8 × 3 cm (length × width × thickness). The treatments were carried out at three temperatures of -20, 60, and 100°C, each at three exposure times (5, 10, and 15 h). Temperature treatment at -20°C was conducted in a domestic freezer, while the treatments at 60 and 100°C were administered in a Parr reactor, where the timber was submerged in water. Regardless of the exposure time, the timbers heat-treated at 100°C showed more efficiency, since this treatment unclogged the pores, reduced hygroscopicity, and promoted further darkening and uniformity of color, without changing the density and mechanical strength of the wood.

The soybean-corn succession in no-tillage system (DSS) is the most common cultivation practice in the state of Mato Grosso. Soils submitted to this type of system are prone to the formation of fertility gradients and surface compaction, restricting crop productivity. The objective of this work was to evaluate the physical-chemical attributes of an Oxisol after 11 years of continuous succession of soybean and corn in direct seeding, using geostatistical analysis techniques and main components. The experiment was conducted at the Chão Nativo farm located in the municipality of Sinop, Mato Grosso, Cerrado-Amazonian ecotone. For this, a rectangular mesh was installed with 103 sampling points distributed in an area of 7.02 ha, in which the grain yield of the soybean was determined as well as the physical and chemical attributes of the soil in the layers 0-10 and 0.10 - 0.20 m. Soybean showed a grain yield between 2.83 and 3.70 Mg ha-1, which was positively correlated with the spatial distribution of pH, phosphorus and potassium. The soil presented low physical quality due to high soil resistance to penetration and macroporosity less than 10%; however, no spatial correlation of physical attributes with soybean yield was observed.

The objective of this work was to evaluate the physicochemical and microbiological characteristics, antioxidant capacity and phenolic compounds of organic cherry tomatoes grown under fertigation with organic dairy cattle wastewater (DCW) with different nitrogen rates. Tomato plants, grown in an agroecological farm in Seropédica, State of Rio de Janeiro, Brazil, were subjected to four different nitrogen rates (T1=0, T2=50, T3=100 and T4=150% of N). The moisture, lipids, ashes, protein and total fiber contents, soluble solids (ºBrix), reducing and total sugars (%), pH and total titratable acidity (mg NaOH per 100 g) were evaluated. The total phenolic content (TPC) and the antioxidant capacity was determined by the DPPH and FRAP methods. The different nitrogen rates (%N) affected the pH, protein and soluble solids contents. The increase in %N increased the antioxidant capacities, according to the DPPH assay, and TPC. On the other hand, the tomatoes under fertigation with the highest %N presented lower antioxidant capacities according to the FRAP assay. The fertigation did not affect the microbiological characteristics of the tomatoes, which presented fecal coliforms count <3 NMP g-1 and absence of Salmonella in 25 g.

Knowledge of the interactions between soil physical properties and yield performance in agricultural crops is very important for the adoption of appropriate management practices. This study aimed to evaluate the linear and spatial correlations between some soil physical attributes, straw production in the palisade grass (Urochloa brizantha), and grain yield of winter common bean in succession to the grass under an irrigated no-till system in an Oxisol Haplorthox in the Cerrado lowlands region of Brazil. The plant attributes determined were dry matter yield of U. brizantha (DMY), and grain yield (GY) and final plant population (PP) of winter common bean. The soil physical attributes, evaluated at 0.0-0.10 m and 0.10-0.20 m, were soil bulk density (BD), macroporosity (MA), microporosity (MI), total porosity (TP), penetration resistance (PR), gravimetric water content (GW), and volumetric water content (VW). A geostatistical grid with 124 sampling points was installed to collect the soil and plant data in an area of 4000 m2. The remaining straw amount of palisade grass exhibited an inverse linear correlation with bean yield and bean plant population when the bean was cultivated in succession. However, no spatial correlations were observed among the attributes. The common bean yield had a direct linear correlation with gravimetric water content in the 0.10-0.20 m soil layer. From a spatial point of view, winter bean yield showed a strong dependence on the distribution of the volumetric water content in the 0-0.10 m soil layer.

ABSTRAT: Psidium guineense Sw, popularly known as araçá, is a fruit tree there is widely distributed in Brazil and belongs to the Myrtaceae family. In northeastern Brazil, araçá occurs along coast and in the Zona da Mata; its fruit looks like guava but is more acidic and has a stronger smell. There is a little information about this species, which increases the difficulty of conserving its genetic resources and exploiting araçá as an economic resource. The objective of this research was the evaluation of the genetic diversity and genetic structure of P. guineense from Pernambuco's Zona da Mata. One hundred and fourteen individuals and 18 isozyme loci were evaluated, showing 28 alleles. The percentage of polymorphic loci () and the average number of alleles per locus () were 0.5 and 1.5, respectively, in this population. The expected heterozygosity, which corresponds to the genetic diversity, ranged from 0.22 to 0.23, a high value when considering that isozymes mark access from the functional genome. The differentiation index among the population was () = 0.015; therefore, the populations were not different among the sampled places. The inbreeding values () ranged from -0.549 to -0.794, indicating an absence of inbreeding and a greater-than-expected heterozygosity in all the studied populations. The estimated gene flow (Nm) for a pair of this population ranged from 3.23 to 20.77, sufficient to avoid genetic differentiation among the population and in accordance with the values of genetic divergence found in this study. | RESUMO: Psidium guineense Sw., conhecida popularmente como araçá, é uma fruteira pertencente à família Myrtaceae que tem ampla distribuição geográfica. Nos Estados do Nordeste Brasileiro ela ocorre principalmente na faixa litorânea e Zona da Mata. O fruto do araçazeiro tem sabor que lembra o da goiaba, ligeiramente mais ácido e de perfume mais acentuado, e sua exploração é feita de modo extrativista. As informações sobre esta espécie são escassas, o que dificulta a conservação dos recursos genéticos e sua exploração econômica. Neste trabalho foram estudadas a diversidade e estrutura genética de quatro populações de araçá, tendo sido avaliados um total de 114 indivíduos por meio de 18 loci isoenzimáticos que revelaram 28 alelos. A porcentagem de locipolimórficos () e o número médio de alelos por loco () nas populações foram 0,5 e 1,5, respectivamente. A heterozigosidade esperada (), que corresponde à diversidade gênica, variou entre 0,22 e 0,23, valores altos, principalmenteconsiderando-se que isoenzimas acessam a porção funcional do genoma. O índice médio de diferenciação () entre as populações foi de 0,015, portanto, as populações basicamente não diferem entre os locais amostrados. O índice de fixação () variou de -0,549 a -0,794 indicando ausência de endogamia e excesso de heterozigosidade nas populações. O fluxo gênico (Nm) estimado para os pares de populações variou de 3,23 a 20,77, valores que corroboram com a ausência de diferenciação observada entre estas.