The savanna woodlands of Piauí state has great economic importance since it is an area for agricultural expansion, being the fourth most important of Brazil and the first from Brazilian Northeastern. The area accounts for 5.9% of the Brazilian savanna woodlands and 36.9% of the Northeastern savanna, covering 46% of the Piauí state area, in a total of 11.5 million hectares . The goal of this research was to study pedoenvironments of Serra do Quilombo region, which is in Piauí state savanna, as well as identifying existing soil classes, according to the Brazilian System of Soil Classification - SiBCS. Soil identification consisted in characterizing soil profiles along a transect, assessing in - field conditions and collecting soil samples, in areas of native vegetation. The samples were gathered from three distinct points, being two at the edges and one at the center of the plateau. Soil analyses were carried out with samples collected from each horizon through trench digging up to a 2 - m depth. Morphological, physical, chemical and mineralogical characterizations were performed for each soil profile , along with an evaluation of the effect of pedogenic factors on their formation and development. All soils under study were formed with source materials of the same geological formation; however, each rock has a distinct contribution to the process, involving sandstones and shales. The characteristics observed in the soil from Serra do Quilombo have no difference from the pattern found in the Brazilian plateaus, and soil profiles were classified as dystrophic clayey Yellow Latosols (Oxisols), according to the SiBCS .

Lettuce is one of the most produced and consumed leafy vegetables in Brazil. It is harvested when the plant reaches full vegetative growth and the leaves are still tender and there are no signs of bolting. The plant is unsuitable for commercialization after this period, thus, a food that is rich in vitamins, minerals and bioactive compounds such as carotenoid is lost. Therefore, the objective of this work was to assess the purple lettuce quality based on physical-chemical characteristics, in three different ages. The experiment was conducted in an urban community garden in Sete Lagoas MG, Brazil. A completely randomized experimental design was used with three replications. The treatments consisted of three development stages (20, 30 and 40 days after transplanting - DAT). The treatment with 40 DAT presented total carotenoids concentration and soluble solids content significantly higher, lower pH, and darker lettuce, with lower values of the parameter b* (increase in yellow color), and higher values of the parameter a* (increase in red color), compared to the first two treatments. The titratable acidity was statistically equal for the three evaluation periods. Considering the high concentration of carotenoids found at 40 DAT, the harvest can take place at this age.

This study assessed the effect of different irrigation levels and plant densities on maize crops cultivated during the second season in the Western Border region of the State of Rio Grande do Sul. This work was conducted at the Federal Institute of Farroupilha – Alegrete Campus/RS – between January and June 2014. Treatments were arranged in a completely randomized 5 × 4 factorial design, with 3 replicates each. Irrigation of fixed amounts of water that were based on the evapotranspiration of the culture (Etc): 0, 50, 75, 100, and 125% of Etc were applied at 5-day intervals. Four densities of plants were defined (4, 7, 10, and 13 plants m-2). We assessed number of maize ears per plant, number of grains per ear, aboveground dry matter, mass of 100 grains, harvest index, and grain productivity. The number of grains per ear, mass of 100 grains, and grain yield were influenced by irrigation levels. Plant density and water depth influenced the number of grains per ear, the mass of 100 grains, and grain productivity. The highest yield of winter maize grain was achieved with a combination of 13 plants per m-2 and an irrigation level of 100% of Etc. Specific densities of plants maximized the yield of maize at each irrigation level, demonstrating that choice of plant density is a critical variable in the second crop of maize, and significantly influences the components of production.

Changes in soils management systems, including the application of green manure, are able to increase crop productivity. The aim of this study was to propose a soil management system with the use of green manure to improve the nutritional status and melon productivity in the submedian of the São Francisco Valley. The experiment was installed in Typic Plinthustalf and conducted in split plot. There were two soil tillage systems, tillage (T) and no tillage (NT), and three types of green manure (two vegetal cocktails: VC1- 75% legumes (L) + 25% non-legumes (NL); VC2- 25% L+ 75% NL and spontaneous vegetation (SV)). The experimental design was a randomised block with four replications. Fourteen species of legumes, grasses and oilseeds were used for the composition of the plant cocktails. We evaluated production of the dry shoot and root biomass and carbon and nutrient accumulation by green manures and melon plant. Data were subjected to analysis of variance and the treatment means were compared by Tukey´s test (P<0.05). Shoot biomass production and carbon and nutrient accumulation were higher in plant mixtures compared to spontaneous vegetation. The root system of the plant cocktails added larger quantities of biomass and nutrients to the soil to a depth of 0.60 m when compared to the spontaneous vegetation. The cultivation of plant cocktails with soil tillage, regardless of their composition, is a viable alternative for adding biomass and nutrients to the soil in melon crops in semi-arid conditions, providing productivity increases.

The objective of this study was to characterize the floristic composition, vegetation structure and ecological group of tree species in a cerradão forest (Cerrado biome) of Palmas, Tocantins State, Brazil. A forest inventory was performed in an area of 10.15 hectares, using systematic sampling with plots of 400 m², in which all standing trees, alive and dead, that had diameter at breast height (DBH) ≥ 5 cm were sampled and identified. A linear plateau regression model (LPR) was used for sample sufficiency analysis. The Shannon index (H’) was used for assess the floristic diversity, and the Importance Value Index (IVI) for assess the horizontal structure. The forest was classified in three strata according to vertical structure analysis. The LPR showed that the sampling size was adequate. The predominate species in the area were Myrcia splendens, Emmotum nitens and Qualea parviflora, and species from the families Fabaceae and Chrysobalanaceae. The pioneer (613 individuals ha-1) and climax (530 individuals ha-1) species were the predominating groups. Regarding the richness index, the number of climax (57 species) and pioneer (25 species) species stood out. The alpha floristic diversity was 3.35 nats individuals-1 and the Pielou equability value J = 0.76. The diametric distribution showed a negative and balanced exponential pattern. Regarding the vertical stratification, the smallest amount of individuals was in the upper stratum (13%) and the highest in the mid stratum (63%) and in the lower stratum (24%). The use of floristic composition tools with horizontal and vertical structure analysis was effective for understand the tree community, which may be considered structured and diverse, thus able to restructure possible disturbances when preserved.

The objective of this work was to verify the presence of genotype - environment interactions (GEI) on the weight adjusted to 365 days of age (W365) for Tabapua cattle in the Northeast of Brazil, using reaction norm (RN) models. The reaction norm model with homogeneous residual variance and 1 - step provided the best fit to the data by the criteria information of deviance, deviance based on the conditional predictive ordinate and deviance based on the Bayes factors. Direct and maternal heritability estimates for the animal model were 0.17±0.04 and 0.07±0.03, respectively. The direct heritability for model reaction norm in the low and high management environment were 0.21±0.06 and 0,70±0.04, respectively. The correlations between the slope and intercept of the reaction norm were 0.68±0.10 and 0.96±0.06 for the direct and maternal effect, indicating that the animals with high genetic values respond positively to environment improvements, especially for the maternal effect. The Spearman correlations between the sire classifications ranged from 0.14 to 0.94 in the different environments and models. Genetic values of most animals were robust to environmental variation, however, considering the sires with the highest number of progeny, there is the presence of GEI.

Saflufenacil is absorbed by the plant leaves and roots, thus the residual permanence of this herbicide can cause losses to the crop plants. Therefore, the objective of this study was to evaluate the selectivity of the saflufenacil herbicide, applied singly and in combination with glyphosate, on coffee and citrus plants grown in a sandy soil. Two experiments were implemented and conducted in completely randomized design with four replications. The chemical treatments consisted of three sequential applications, with directed spraying of saflufenacil at rates of 0.035, 0.07 and 0.105 kg a.i. ha - 1 , glyphosate at rate of 2.160 kg a.e. ha - 1 , the two herbicides combined at the same rates, and a control without chemical treatment. The saflufenacil applied singly and in combination with glyphosate was selective for coffee and citrus plants, which presented no visual toxicity symptoms. The sequential application of saflufenacil, singly and in combination with glyphosate did not affect the growth of coffee and citrus plants. The saflufenacil has potential for use, in combination with glyphosate on controlling many weed species in coffee and citrus areas without any interference on the development of these species.

Irrigation using produced water, which is generated during crude oil and gas recovery and treated by the exploration industry, could be an option for irrigated agriculture in semiarid regions. To determine the viability of this option, the effects of this treated water on the nutritional status of plants should be assessed. For this purpose, we examined the nutritional changes in sunflowers after they were irrigated with oil - produced water and the effects of this water on plant biomass and seed production. The sunflower cultivar BRS 321 was grown for three crop cycles in areas irrigated with filtered produced water (FPW), reverse osmosis - treated produced water (OPW), or ground water (GW). At the end of each cycle, roots, shoots, and seeds were collected to examine their nutrient concentrations. Produced water irrigation affected nutrient accumulation in the sunflower plants. OPW irrigation promoted the accumulation of Ca, Na, N, P, and Mg. FPW irrigation favored the accumulation of Na in both roots and shoots, and biomass and seed production were negatively affected. The Na in the shoots of plants irrigated with FPW increased throughout the three crop cycles. Under controlled conditions, it is possible to reuse reverse osmosis - treated produced water in agriculture. However, more long - term research is needed to understand its cumulative effects on the chemical and biological properties of the soil and crop production.

The feeding frequencies on pacamã Lophiosilurus alexandri larviculture were evaluated. In the first phase, 10 days of active feeding, larvae with nine days post hatching (13.5 ± 0.7 mm) were stocked at density of 10 larvae L-1 in 5-L tanks each. The experimental treatments were: F2T (feeding 8h00 and 17h00); F2M (feeding 8h00 and 12h30); F3 (feeding 8h00, 12h30 and 17h00); and F4 (feeding 8h00, 11h00, 14h00 and 17h00). During this phase Artemia nauplii were used as food. In the second phase, during 15 days, juveniles were restocked in 20-L tanks at density of 2.2 juveniles L-1, and kept the same feeding frequencies of the first phase. Commercial dry diet containing 40% crude protein was used as food. No effect of feeding frequency on growth and survival, during both phases, was observed. However, survival decreases from the first to the second phase, showing the importance of the type of food. During the L. alexandri larviculture should be recommended twice a day feeding frequency.

Pigeon pea is an important protein source grown in several tropical and sub - tropical countries, and is considered a multi - purpose plant that is resistant to the conditions of the Brazilian Cerrado. Among the possible uses for cowpea, its use as a green manure, increasing soil nitrogen content through the association with diazotrophic bacteria, generically known as rhizobia, is noteworthy. The present work aimed to evaluate the efficiency of Rhizobium strains isolated from cowpea plants in the development of pigeon peas cultured in Red Latosol. The experiment was conducted in a greenhouse, using a completely randomized design with seven treatments and four replications. Treatments consisted of inoculation with four Rhizobium strains (MT8, MT15, MT16, and MT23) and one commercial inoculant comprising Bradyrhizobium spp. strains BR 2801 and BR 2003. There were two controls, one absolute (without inoculation or nitrogen fertilization) and the other with nitrogen fertilization. Each experimental plot consisted of an 8 - dm 3 vase containing three plants. Analyzed variables included plant height, SPAD index, number and dry weight of nodules, and shoot and root dry masses. Pigeon peas responded significantly to inoculation treatment, since all the plants inoculated with Rhizobium strains isolated from cowpea strains showed results similar to plants in the nitrogen control and commercial inoculant treatments. This demonstrates a favorable plant – bacteria interaction, which can be utilized as an alternative nitrogen source for pigeon peas.