Nova Xavantina Research Articles

Development of tree species in an agroforest system in Nova Xavantina, Mato Grosso, Central Brazil

As the arrangement of the species is fundamentally important to guarantee the effectiveness of agroforestry systems, it is important to test different combinations of species with varying levels of economic potential. The study was based on the analysis of the initial development of an agroforestry system formed by native tree species and other plants of economic interest, intercropped with green manure species under the edaphoclimatic conditions of Nova Xavantina in Mato Grosso, central Brazil. The study was conducted in an experimental plot on the Nova Xavantina campus of Mato Grosso State University. The plot was arranged in randomized blocks, in a simple agroforestry system of the alley type, with the plants arranged in rows, in a 4x2 factorial design (four fruit species x two legumes). The fruiting species included five trees – Bixa orellana, Spondias lutea, Byrsonima crassifolia (L.) Rich, Pouteria ramiflora, and Theobroma grandiflorum, and the banana, Musa sp. (the “BRS Princesa” cultivar). Two combinations of legume species were tested – (i) Cajanus cajan and Vigna unguiculata,and (ii) Mucuna aterrima and Canavalia ensiformis. Tree growth was assessed based on four phytometric parameters – plant height, stem diameter, the number of leaves, and percentage survival, while for Musa, the parameters were height and pseudostem circumference, and the number of active leaves and shoots. Bixa orellana and S. lutea were the species best adapted to the edaphoclimatic conditions found in the experimental plot, with all (100%) of the Bixa plants surviving throughout the study, and a survival rate of over 70% in S. lutea.

Late Tonian explosive volcanism and hyaloclastites in northern Paraguay Belt, Central Brazil: A record of Rodinia break-up in western Gondwana

Explosive volcanism and oceanic crust generation are key aspects to understanding the break-up history of the Rodinia. Its impact on the extreme glaciations of the Cryogenian was marked by ocean chemistry fluctuations in these times, which are still poorly known and preserved in western Gondwana. Here we describe in detail and provide a series of U-Pb ages for the Nova Xavantina Metavolcanosedimentary Sequence, where extrusive rocks, such as hyaloclastite and metabasalts, as well as mafic and ultramafic intrusive rocks and ignimbrites, are associated with diamictites, limestones, and iron formations in the Paraguay belt, Central Brazil. Two styles of pyroclastic eruptions were identified in the studied area. Basic-ultrabasic Surtseyan eruption was enhanced by magma-water interaction and is represented by hyaloclastites and incorporated bombs of scoria. Felsic Plinian eruption, in its turn, was formed by violent explosions in a subaerial environment and is represented by widely exposed acidic tuffs and ignimbrites. Shallow subaqueous environments, such as lakes, salt lakes, and possibly proto-oceans, developed in this precursor basin concomitant with bimodal volcanism. High resolution U-Pb geochronology results indicate they were formed in at least three magmatic events, starting with the formation of ca. 745 Ma seafloor metabasalts and felsic volcanics dated at ca. 735 Ma, and intrusive gabbros at ca. 714 Ma. Alkaline ultramafic rocks of ca. 577 Ma intrude the region and may be associated with similar rocks that crop out regionally as the Planalto da Serra Alkaline Complex. Our results from Nova Xavantina volcanism explain the main Neoproterozoic source until now unrecognized and previous recorded in detrital zircons from the Paraguay belt sediment provenance.

Quality of family lives: perception of PNCF beneficiaries in Nova Xavantina, Mato Grosso, Brazil

This article is the result of a doctoral research that aims to investigate how the family farmers of the Pé da Serra and Beira Rio Settlement, located in the municipality of Nova Xavantina, Mato Grosso, Brazil, see changes / improvements in the quality of life of families, as a result of access to land by PNCF, and the direct repercussions of these on the social and economic reproduction of individuals. The methodology used includes bibliographic review, consultation of data from secondary sources, application of questionnaires to 43 farmers and interviews. The results showed that, in general, there were significant improvements in the quality of life of households after access to land through the PNCF, not only in relation to the acquisition of durable goods, but also in relation to aspects such as housing, purchasing power, leisure, security and future prospects, as well as the feeling of belonging to a place / territory. Other aspects that reflect on the quality of life of families are incipient, especially with regard to collective production infrastructures, forms of social organization (based on the Beira Rio Association) and the interaction of this organization with the settled community, restricted only to initial formation of these settlements.

Evaluation of the sweet potato cultivars, in Nova Xavantina - Mato Grosso, Brazil / Avaliação de cultivares de batata-doce em Nova Xavantina - Mato Grosso, Brasil

Sweet potato is one of the world’s most important crops, given its high productivity and short growing cycle, being ready for harvest in 150–180 days. It is also considered to be a viable alternative to sugarcane for the production of ethanol. The present study investigated the productivity of five sweet potato cultivars, their potential for the production of ethanol, and their resistance to insects pests. The study was conducted in an experimental plot in the municipality of Nova Xavantina, in the state of Mato Grosso, central Brazil. The experimental design was based on randomized blocks with four repetitions, 40 plants per plot, and five treatments, which were the different sweet potato cultivars (Vilma, Carolina Vitória, Nataly, Amanda, and Duda) earmarked for the production of ethanol. Under the conditions of the experiment, the Nataly cultivar presented the best results in terms of the biomass produced, resistance to ground-dwelling insect pests, and productivity, and was thus the sweet potato cultivar considered to be most appropriate for the production of ethanol in the study region.

Identification of regions of constitutive heterochromatin and sites of ribosomal DNA (rDNA) in Rhogeessa hussoni (Genoways & Baker, 1996) (Chiroptera; Mammalia; Vespertilionidae)

There is scarce information about the geographical distribution, biological and cytogenetic data from the Rhogeessa hussoni. This study aims to characterize its chromosome composition through chromosome bandings to visualize regions of constitutive heterochromatin (CGB bands) and sites of ribosomal DNA (rDNA) in R. hussoni’s karyotype. A female specimen of R. hussoni was collected in the “Parque Municipal Mário Viana” Conservation Unit, Nova Xavantina, Mato Grosso, Central-West region of Brazil. The karyotype constitution was 2n=52 and NF=54. The CBG bands evidenced a sex X chromosome nearly completely constituted by heterochromatin. The Rhogeessa hussoni has two sites of rDNA located in a single pair (pair 25) of autosomal chromosomes. We carried out the first cytogenetic characterization of R. hussoni, supplementing knowledge about regions of heterochromatin and ribosomal DNA in this species, thus contributing to future elucidations about the genetic diversification in the genus Rogheessa.

Bioclimatic diagnosis for poultry in municipalities of Mato Grosso, Brazil

This study aimed to determine the enthalpy index in three municipalities of Mato Grosso, to characterize the bioclimatic profile for the poultry industry. In the research, the compensated daily dry bulb temperature and the daily average relative humidity were used. The data corresponding to a historical series of 35 years, between 01/01/1985 and 12/31/2020, recorded in conventional meteorological stations in the municipalities of Canarana, Nova Xavantina, and Santo Antônio de Leverger, available in the Meteorological Database for Teaching and Research of the National Institute of Meteorology (INMET). Then, monthly descriptive statistics of the historical series were determined and bar plot graphs with enthalpy values were developed. These graphs included the lower and upper enthalpy limits, suitable for laying hens and broilers, to qualify the thermal conditions of environmental comfort in the three municipalities of Mato Grosso. It was concluded that the enthalpy index made it possible to characterize the bioclimatic profile of the mentioned municipalities for poultry farming, according to the months of the year. The natural thermal conditions in these municipalities were not favorable to poultry farming, requiring extra investments in the air conditioning of the sheds. The increase in thermal discomfort for broilers was accentuated from the fourth week of the production cycle. The applied methodology presented itself as an adequate tool to assist in the elaboration of projects related to environmental changes in aviaries.

Interseeding of ruzigrass into soybean: Strategies to improve forage cultivation in no-till systems

No-till (NT) farming is a major soil conservation strategy. In the Brazilian Cerrado, soybean is the main grain crop, and strategies that improve the cultivation of cover crops in the off-season in succession to soybean could facilitate NT for large cultivated areas. In the municipality of Nova Xavantina, MT, Brazil, three experiments were carried out in a randomized block design with four replications. This work aimed to evaluate the establishment of Urochloa ruziziensis (ruzigrass) in succession to soybean as a function of ruzigrass seed treatment, sowing density and phenological stage, and soybean cultivar allelopathic potential. In the first experiment, treatment of ruzigrass seeds with six doses (0, 150, 300, 450, 600 and 750 mL of commercial product 100 kg−1 of seeds) of fipronil + thiophanate-methyl + pyraclostrobin was evaluated. In the second experiment, two ruzigrass interseeding periods (soybean phenological stages R5.5 and R7) and five ruzigrass seed densities (4.3, 6.4, 8.6, 10.7 and 12.9 kg ha−1 VPS) were tested. In the third experiment, the interference of soybean cultivars in the establishment of ruzigrass and the potential allelopathic effect of the cultivars on forage germination were evaluated, six soybean cultivars RR (Roundup Ready®) were used: P98Y70; TMG 115; TMG 132; M 8527; P98Y11; TMG 123. Our results showed that seed treatment facilitated forage establishment in the interseeding system, and the use of high sowing rates at phenological stage R5.5 of soybean promoted greater ruzigrass plant development. The effects of the soybean cultivars on ruzigrass germination varied, suggesting allelopathic effects of the deposition of petioles and soybean leaves on ruzigrass seeds. Thus, an appropriate interseeding strategy can improve forage production in the off-season and favor NT through correct management of forage establishment in succession to soybean.

Entre as conexões e as desconexões: experiências acadêmicas em tempos de distanciamento social físico

A presente pesquisa objetiva conhecer formas de comunicação utilizadas pelos estudantes do câmpus UNEMAT Nova Xavantina a fim de “vencer” o distanciamento físico e como estas podem impactar no engajamento com o processo de ensino-aprendizagem adotado pela IES. A pesquisa apresenta caráter exploratório quanto aos seus objetivos, quanti-quali quanto à abordagem do problema e como delineamento optou-se pelo estudo de caso. A técnica escolhida para a geração de dados foi o questionário. Os resultados indicam que há um movimento intenso em termos de tentativas de adaptação. Os alunos, apesar da desenvoltura no que se refere às tecnologias, sentem-se confusos, inseguros quanto à sua capacidade de processar tantas informações ao mesmo tempo, sejam elas conteúdos que devem ser estudados, quanto habilidades que precisam ser desenvolvidas e/ou aprofundadas para terem acesso ao ensino remoto emergencial adotado pela IES. Ao mesmo tempo, visualizam oportunidades de aprender de forma mais dinâmica e flexível.

Professional perspective of the labor Market by trained stdents and motivational factors ins the evasion of graduates from the agronomy course in Nova Xavantina

The University causes changes in the lifestyles of academics, during graduation and after graduation. Many do not work in the area that was graduated and some even do not finish college, today it is a reality observed in all higher education courses and some cases intensified due to the size of the hours and other peculiarities. In view of this premise, we sought to identify the influence of the dynamics of the Agronomic Engineering Course at the State University of Mato Grosso, New Xavantina campus on why students drop out of college, and feedback from those who have already graduated. Evaluate the professional perspective of the labor market by trained students. To observe the motivational factors in the avoidance of graduates in the course of agronomy. Analyze the trajectories of professional development throughout the university experience that lead to different expectations and ways of preparing for the job market. A questionnaire was applied through innovative teaching approaches using Web 2.0 tools, in particular Google Docs, "forms". The questionnaire link was provided by email, SMS, Facebook, Instagran and WhatsApp to the target audience. It is concluded that the evasion in the University of Mato Grosso State Nova Xavantina campus occurred for three reasons: the agronomy course was the second choice of the academic, and the lack of knowledge of the course and support of family members. Based on the perspectives of post-graduates, one can conclude that: (1) the greatest difficulty was to obtain employment, (2) about 81% are working in their training area, (3) the agronomy course was the first option of the trained students, that is, they began the course aware of the difficulties, and yet they persevered and concluded the course.

Family Farming and Commercialization: the case of the covered fair in Nova Xavantina-MT

This study aimed to evaluate the experiences of family agriculturists who sell their products in the Covered Fair of Nova Xavantina - MT, from the different strategies used by them, their problems and prospects in relation to income generation and maintenance of families . We surveyed 14 familiar producers and 14 consumers. These numbers have not been defined by statistical criteria, which is characterized by a search combining a quantitative and qualitative approach. The instruments used for data collection consisted of questionnaires, direct observation and interviews. By this research it could be seen that the Covered Fair is an important space of conviviality, trade and consumption, however, this place is still little appreciated by the population and producers. The lack of infrastructure and the stiffness of supervision does not bring attractive to many farmers in the municipality and this is directly reflected in the marketing and purchase of products from family farms, important sector in terms of economic and social development. Thus, public policies for production, consumption and trade are essential for greater inclusion of family farmers in the municipality of Nova Xavantina and region.

Shortening history of the Neoproterozoic oroclinal bending in Paraguay belt, Central Brazil, based on structural interpretation of field work and high resolution aerogeophysical data

Different phases of the orogen's evolutionary history can be geometrically restored by identifying associated tectonic features in the thrust-and-fold belts in the foreland basin. The geometry and fold styles allow understanding the rate of crustal shortening of the Paraguay Belt Neoproterozoic oroclinal. We suggest that high resolution airborne geophysical data provides critical information to understand the tectonic history of Brasiliano fold belts. Geophysical studies integrated to structural analysis in field mapping may unveil the crustal architecture as well as the sequence of events of rocks exposed in two structural windows of the basement in the region of Planalto da Serra and Nova Xavantina, in the state of Mato Grosso, northern segment of the Paraguay Belt, Central Brazil.The evolutive history of rocks exposed southwards of the Amazonian craton margin represents extensional tectonics followed by the development of a passive margin. It is estimated that the original width of the depositional space was ~350 km during the formation of the hyperextended platform and, after the intense shortening during the Brasiliano orogenesis, the oroclinal was restricted to ~130 km wide, in the post-deformation phase. Planalto da Serra region is characterized by asymmetrical, harmonic folds with thickened hinge zones. They show variable styles between tight and isoclinal and form pairs of EW and NE anticlines and synclines. In Nova Xavantina structural window, the magnetic lineaments mark important lithospheric discontinuities represented by the Campinápolis (CAL) and General Carneiro (GCL) lineaments, which seem to be the deep basement faults that controlled the extension and where the rift axial zone developed. The Transbrasiliano Lineament (TBL) is a major shear zone that controls the secondary lineaments propagation, forming a network of folds and drag faults, with lateral escapes and vertical movement. Between the two main lineaments occurred the deposition of sediments and volcanic successions related to Nova Xavantina Metavolcanosedimentary Sequence representing a marginal ocean basin. The transition from EW trending features of the Paraguay Belt to NE trend Araguaia Belt lies within Nova Xavantina region and is marked by the direct influence of TBL. TBL is evident in the magnetic images, forming a mosaic of different crustal blocks and corresponding to various curvilinear shear zones with unidirectional trend N30-45E. It is composed of mega-sigmoids interlaced with mainly dextral kinematics, within shallow and deep levels.During the Neoproterozoic orogeny, a foreland basin system was formed in response to the flexural subsidence due to the tectonic inversion of the basin. Several depocenters were formed and served as accumulation sites for the deposition of sediments of the Alto Paraguay Group (Raizama, Sepotuba and Diamantino formations). Gravimetric data allowed individualization of the foreland basin system, which is characterized by four discrete depozones (back-bulge, forebulge, foredeep and wedge-top), between the Amazonian Craton and the inner structural zone.

Perfil dos óbitos por coronaví­rus (COVID-19) em Mato Grosso: Reflexos da flexibilização no estado

Objetivo: Analisar o perfil epidemiológico os óbitos por COVID-19 em Mato Grosso, de abril a junho de 2020, segundo variáveis demográficas e decretos de abertura as atividades comerciais. Métodos: Trata-se de um estudo transversal e ecológico com dados dos Boletins Informativos da Secretária do Estado de Saúde de Mato Grosso. Consideraram-se os óbitos, número, sexo, faixa etária. para a construção de mapas temáticos utilizou-se os municí­pios de residência dos óbitos. Resultados: Dos casos confirmados, 3,8% foram a óbitos (661 óbitos), destes, 61,0% eram homens, 46,8% tinha entre 61 a 80 anos. A maior taxa de mortalidade ocorreu no municí­pio de Ponte Branca (63,5/100 mil hab.), e em Nova Xavantina (57,1%). Conclusão: Foi observada maior frequência dos óbitos por COVID-19 nos homens, idosos, nas regiões Centro-Sul e Sudoeste do estado, com aumento de óbitos 500%.

Perfil epidemiológico dos óbitos por Coronaví­rus (COVID -19) em Mato Grosso

Objetivo: Analisar o perfil epidemiológico os óbitos por COVID-19 em Mato Grosso, de abril a junho de 2020, segundo variáveis demográficas e de doenças pré-existentes (DPE). Métodos: Trata-se de um estudo transversal e ecológico com dados dos Boletins Informativos da Secretária do Estado de Saúde de Mato Grosso. Consideraram-se os óbitos, número e tipo de doença pré-existente, taxa de mortalidade e letalidade para a construção de mapas temáticos. Resultados: Dos casos confirmados, 3,8% (661 óbitos) morreram, destes, 61,0% eram homens, 63,3% tinha 61 anos ou mais, e 72,9% apresentavam doença pré-existente, sendo 39,3% hipertensão, 27,9% diabetes e 12,1% patologias do aparelho circulatório. A maior taxa de mortalidade ocorreu no municí­pio de Ponte Branca (63,5/100 mil hab.), e em Nova Xavantina (57,1%) a maior letalidade. Conclusão: Foi observada maior frequência dos óbitos por COVID-19 nos homens, idosos e com doença pré-existente, nas regiões Centro-Sul e Sudoeste do estado.

SUBSTRATES AND CONTAINER VOLUMES IN THE PRODUCTION OF MANGABEIRA SEEDLINGS (Hancornia speciosa Gomes)

Mangabeira (Hancornia speciosa Gomes), a fruit tree native to the Brazilian Cerrado, has great potential for commercial cultivation due to the quality of fruits, which can be consumed fresh or processed. However, it is necessary to expand research in the area of propagation of this fruit tree. The aim of this study was to evaluate different substrates and container volumes in the production of mangabeira seedlings, H. speciose, in Nova Xavantina-MT. The experiment was carried out at the nursery of the Mato Grosso State University (UNEMAT), Campus of Nova Xavantina in a randomized block design, in a 2 x 4 factorial scheme, with two container volumes (0.9 e 1.8 dm3) and four substrates (soil; soil + sand; soil + sand + bovine manure; and commercial substrate), totalizing eight treatments with four replicates and plots composed of 10 plants each. The greatest growth of mangabeira seedlings was observed using soil or soil + sand + bovine manure and 1.8 dm3 container.

A new myxozoan species Henneguya unitaeniata sp. nov. (Cnidaria: Myxosporea) on gills of Hoplerythrinus unitaeniatus from Mato Grosso State, Brazil.

On the basis of morphological and molecular analyses, a new myxozoan parasite is described from the gills of the fish Hoplerythrinus unitaeniatus, collected in the municipality of Nova Xavantina, Mato Grosso State, Brazil. Plasmodia of Henneguya unitaeniata sp. nov. were oval and whitish and were found surrounded by collagen fibers forming plasmodia wall between gill filaments on the gill arch. The spores were ellipsoidal with two similar polar capsules. Morphometric analysis showed a total spore mean length of 23.8 ± 1.5 μm, spore body mean length of 14.5 ± 0.7 μm, caudal appendage mean length of 10.3 ± 1.4 μm, thickness mean length of 4.3 ± 0.3 μm, polar capsule mean length of 4.2 ± 0.5 μm, polar capsule mean width of 1.8 ± 0.3 μm, spore mean width of 4.8 ± 0.4 μm, and 4-5 polar filament coils. Phylogenetic analysis showed Henneguya unitaeniata sp. nov. as a basal species in a subclade formed by myxozoans that parasitize bryconid fishes.

Leaf structural traits of three species of <i>Qualea</i> Mart. (Vochysiaceae) in a cerradão area in the Cerrado-Amazonian Forest transition

Qualea genus is commonly found in different phytophysiognomies of the Brazilian Cerrado, growing in open ecosystems to closed forest areas, under high irradiances, fires, low availability of nutrients and seasonal water deficit. We compared the leaf structural traits of Qualea grandiflora Mart., Qualea multiflora Mart., and Qualea parviflora Mart., in a cerradão area in the Cerrado-Amazonian forest transition. Leaf samples were collected at Mário Viana Municipal Biological Reserve, in Nova Xavantina, Mato Grosso state, Brasil, and processed according to the usual techniques for optical microscopy. Thick cuticle, stomatal ridges, stomata distributed between the stomatal crypts, density and distribution of tector trichomes, hypodermis, isobilateral mesophyll with few intercellular spaces, abundance of sclerenchyma associated to vascular bundles and the presence of vascular bundle sheath extensions are typical anatomic traits of xerophytic environments. We found qualitative structural differences among the species, with Qualea grandiflora having stomata with ridges distributed among stomatal crypts, and the presence of a hypodermis in Qualea multiflora, and Qualea parviflora. The results suggest that the species are xeromorphic in the region of Cerrado-Amazonian transition having leaf adaptive traits to deal with the environmental variations of their habitat.

Uso de substratos alternativos na produção de mudas de pimenta e pimentão

The seedlings production with adequate quality standards requires substrates that provide chemical and physical characteristics suitable for this purpose. Therefore, the aim of this work was to evaluate different substrates in the production of seedlings of peppers and sweet peppers. The experiment was carried out in the nursery of the State University of Mato Grosso, Campus of Nova Xavantina. For this purpose, the following compounds were compared: commercial substrate (Carolina Soil®), washed sand + carbonized rice straw + bovine manure (1:1:1 v/v/v), washed sand + carbonized rice straw + earthworm humus (1:1:1 v/v /v), Carolina Soil® + carbonized rice straw + bovine manure (1:1:1 v/v/v) and Carolina Soil® + carbonized rice straw + earthworm humus (1:1:1 v/v/v). Two experiments were carried out simultaneously, both performed in a randomized block design. The first one was carried out in factorial scheme 5 (substrates) x 2 (pepper cultivars), with four replications. The second experiment was carried out in a factorial scheme 5 (substrates) x 3 (sweet pepper cultivars), with four replications. The emergence speed index, emergency percentage, shoot height, stem diameter, number of leaves, and fresh and dry masses of shoot, root and total were evaluated. The commercial substrate Carolina Soil® was the most suitable for the production of pepper and sweet pepper seedlings, as it provided better seedling performance. As an alternative substrate, the substrate composed of commercial substrate + carbonized rice straw + bovine manure is recommended.

Growth of churches submitted to different doses of hydrogel and containers

The cultivation of rubber trees in Brazil has been established as a sustainable and profitable activity, despite all the challenges, the production of rubber trees grows considerably each year. In order to optimize this production, it is necessary to develop techniques for the production of seedlings that present vigor and quality. Therefore, the objective of this work was to evaluate the growth of rubber tree seedlings submitted to different doses of hydrogel and containers. The work was carried out in the seedling nursery of the State University of Mato Grosso, Campus Nova Xavantina. The dosages used were 0, 1, 2, 3 and 4g and the containers were polyethylene bags in dimensions 20x30 and 25x35 cm. To evaluate the effect of the treatments on the growth of the rubber tree seedlings the following variables were measured at 90 days after sowing: Height (cm), stem diameter (mm), H / D ratio, number of triphophils, root length), Dry matter of the leaves (g), dry matter of the stem (g), dry matter root (g). The experimental design was a randomized complete block (DBC) in a 2x5 factorial scheme, two containers and five hydrogel doses, with six replicates for each treatment. From the results obtained in the present work it can be concluded that the dosage of 1g.L -1 of hydrogel and the container 25x35 cm were the most suitable treatments for the initial development of the rubber tree seedlings.

Phosphate and nitrogen fertilization in the production of Barueiro (Dipteryx alata Vog.) seedlings

Abstract Barueiro (Dipteryx alata Vog.), a fruit tree native to the Brazilian cerrado, has aroused the interest of producers and consumers due to its almond highly appraised and valued by local markets. To obtain quality barueiro seedlings, balanced fertilization is required, with special attention to the supply of phosphorus and nitrogen, essential for seedling growth and establishment in the field. The aim of this study was to evaluate the growth of barueiro seedlings produced with different phosphate and nitrogen concentrations in Nova Xavantina – MT. The experiment was conducted at the seedling nursery of the Mato Grosso State University (UNEMAT), Campus of Nova Xavantina - MT, from December 2017 to April 2018. The experimental design was randomized blocks (DBC), in a 5 × 2 factorial scheme, corresponding to 5 phosphorus concentrations and 2 nitrogen concentrations, with 10 treatments, 4 blocks and 10 plants per plot, totalizing 400 seedlings. The applied concentrations were 0, 150, 300, 450 and 600 mg kg-1 P2O5 and 0 and 250 mg kg-1 N. The following variables were evaluated: plant height, plant stem diameter, number of leaves, number of leaflets, fresh and shoot and root dry mass and Dickson’s Quality Index. Significant interaction between phosphorus and nitrogen concentrations for all traits evaluated was observed, except for root dry mass. The greatest growth of barueiro seedlings was obtained when the highest phosphorus concentration (600 mg kg-1de P2O5) was used, associated to nitrogen fertilization of 250 mg kg-1. There was no isolated effect of phosphate fertilization on the growth of barueiro seedlings without nitrogen application.

Idades de Resfriamento 40Ar/39Ar da Faixa Móvel Paraguai na Região de Nova Xavantina (MT): Implicações Tectônicas para a Colagem do Gondwana Ocidental

40Ar/39Ar analysis were carried out on biotite crystals from the Paraguay Belt rocks in Nova Xavantina region (Mato Grosso State, Brazil) with the purpose to constrain the age from the regional metamorphic event. The samples are metavolcanic mafic rocks deformed during Brasiliano-Panafrican events. The 40Ar/30Ar plateau ages range from 541.6 ± 0.4 Ma to 531 ± 0.6 Ma and define the cooling period of regional metamorphic event related to the collision between the Amazonian craton and Paranapanema block, the final stages of the western Gondwana assembly. The Paraguay Belt association cropping out in this region comprise metamorphosed sedimentary (chemical and siliciclastic) and volcanic (basic and intermediary) rocks related to an ocean floor geological setting (Xavantina Ocean). This work presents two new ages for two biotite grains and compares with literature data suggesting that the 40Ar/39Ar data here reported and geological evidence indicates that the metabasic rocks present metamorphic ages in the range from 541 Ma to 531 Ma and their protolith about 700-648 Ma or older.