Restos vegetais e aduba����o nitrogenada na micorriza����o e produtividade do arroz de terras altas em sistema plantio direto

The objective of this research was to verify the influence of plant residues and the nitrogen fertilization in covering on the mycorrhization (colonization and number of spores of the arbuscular mycorrhizal fungi), and grain yield of upland rice grown under a no tillage system. The experiment was conducted at the Experimental Farm Station of Unesp/Ilha Solteira Campus, at Selviria (Mato Grosso do Sul State). In the main plots, the leguminous were tested: sun hemp (Crotalaria juncea L.), pigeon pea (Cajanus cajan L.) and velvet bean (Stizolobium aterrimum Piper & Tracy) and the grass: corn (Zea mays L.), millet (Peenisetum americamum L.) and grain sorghum (Sorghum bicolor L.), plus no planted area during the winter, as plant cover. In the subplots, after the rice sowing, the nitrogen fertilization in covering (zero and 75 kg ha(-1) of N at the urea form) was used. The rice grain yield was influenced by the plant residues, but not for the N doses or the interaction. The sorghum grain showed negative influence on the rice productivity. The nitrogen fertilization influenced the number of spores, but not the mycorrhizal colonization or the grain yield, at the time of the crop. Correlation between the studied variable was riot found.

Aplica����o de sil��cio em arroz de terras altas irrigado por aspers��o

The use of chemical elements considered as beneficial to crops has become common among farmers. The silicon case is interesting, since despite not being essential physiologically for rice crop, it demonstrates that through its absorption it promotes benefits. Therefore, this experiment aimed to evaluate the effect of doses of SiO(2) (0, 150, 300, 450, 600, 750 and 900 kg ha(-1)) at seed sowing time, in two upland rice cultivars (IAC 201 and IAC 202), under sprinkler irrigation, during the agricultural years of 2002/03 and 2003/04 in Selviria, Mato Grosso do Sul State, Brazil. The cultivar IAC 202 can present higher yield than IAC 201, with similar industrial quality and lower laying index. Silicon applications were not sufficient to reduce laying index of IAC 201. In general, silicon application does not interfere in grain productivity and industrial yield of the cultivars used.

Altera����es microbiol��gicas, de fertilidade e de produtividade do arroz de terras altas em diferentes manejos de solo e ��gua

In Brazil, the upland rice Culture system is predominant, but its water supply depends of precipitation and its distribution. Sol-lie practices or disturbances on soil conditions may cause alterations that call be detected by microorganisms, which are quite sensitive. This experiment was developed to study microbiological alterations (microbial biomass carbon (MBC), released CO2 (C-CO2), metabolic quotient (qCO(2)) and mycorrhization), as well as alterations in soil fertility and productivity of upland rice, cultivated under different soil and water managements. Cultivar BRS Talento was used in the experiment. The experimental design was a completely randomized block design, with four replications, using three soil managements: no-tillage (NT), heavy disk + leveling disk harrowing (HL), and chisel plowing + leveling disk harrowing (CL), plus three water managements: no irrigation (WD0); water depth 1 (WD1), with irrigation at the reproductive and maturation periods; and water depth 2 (WD2), with irrigation throughout the rice cycle. Autochthones arbuscular mycorrhizal fungi proved to be sensitive to soil and water management. The NT presented the highest values for MO, Ca, SB and V% and the lowest for H+A1. This management, together with irrigation at the reproductive and maturation periods of BRS Talento cultivar, promoted goods results for crop yield and microbiology characteristics.

Strategy of specification of management areas: rice grain yield as related to soil fertility

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Correla����o linear entre componentes da produ����o e produtividade do arroz de terras altas em sistema plantio direto

The rice is one of the main sources of the humanity's feeding. During the agricultural year 2009/2010, in Selviria County, Mato Grosso do Sul State, in the Brazilian Savannah, an experiment was installed with rice upland in a Dystropherric Red Latosol (Typic Acrustox) under no-tillage, irrigated by central pivot, with the purpose of selecting the best components production to explain the variability the irrigated rice yield upland. The geostatistical grid was installed, to collect the data, with 120 sampling points, in an area of 3.0 ha and and homogeneous slope of 0.055 m m(-1). The medium rice yield was of the 5980 kg ha(-1). For the simple lineal regressions, the number of spikelets grenades for panicle presented the best direct potential correlation with the yield rice, given for: PGO = 115,5.NEG(0,770). However, for the multiple lineal regressions, the equation equacao PGO = 2754,30-411,55.NEG-461,07. NEC+436,59. NET it was the one that better she came to esteem the yield rice. However, spatial, it was not possible to establish correlation between the yield rice and the components production, once none of those it presented spatial dependence in their data.

Fishes of the Atlantic Rainforest of Boraceia: testimonies of the Quaternary fault reactivation within a Neoproterozoic tectonic province in Southeastern Brazil

The upper portion of the Rio Guaratuba, located in the Serra do Mar coastal range of Southeastern Brazil, shows biological and geological evidences of being captured and diverted away from its original course in the direction of the Parana River Basin to become a coastal river due to the Quaternary activity of NW-trending faults. Despite draining directly to the Atlantic Ocean, the upper portion of the Guaratuba still maintains an ichthyofauna that is typical of the adjoining Parana River Basin rather than the characteristic fish fauna of the Brazilian coastal drainages. The fish fauna of the upper Guaratuba is an evident testimony of the tectonic process that allowed the faunal interchange between the upland basins and the coastal drainages that probably has been taking place in Southeastern Brazil throughout the long geological history of the passive Brazilian continental margin.

Effects of flooding regime and woody bamboos on tree community dynamics in a section of tropical semideciduous forest in South-Eastern Brazil

The influence of a population of the understorey woody bamboo Merostachys riedeliana and different flooding regimes on tree community dynamics in a section of tropical semideciduous forest in South-Eastern Brazil was examined. A forest section with an area of 1.6 ha composed of 71 adjacent plots was located on a slope ending at the river margin. The section was divided into five topographical sectors according to the mean duration of river floods. In 1991 and 1998 all trees with a diameter at the base of the trunk greater than or equal to 5 cm were measured, identified and tagged, and all live bamboo culms were counted. Annualised estimates of the rates of tree mortality and recruitment, gain and loss of tree basal area, and change in bamboo density were calculated for each of the 71 plots and five topographical sectors as well as for diameter classes and tree species. To segregate patterns arising from spatially autocorrelated events, geostatistical analyses were used prior to statistical comparisons and correlations. In general, mortality rates were not compensated by recruitment rates but there was a net increase in basal area in all sectors, suggesting that the tree community as a whole was in a building phase. Tree community dynamics of the point bar forest (Depression and Levee sectors) differed from that of the upland forest (Ridgetop, Middle Slope and Lower Slope sectors) in the extremely high rates of gain in basal area. The predominant and specialised species, Inga vera and Salix humboldtiana, are probably favoured by relaxed competition in an environment stressed by long-lasting floods. In the upland forest, mortality rates were highest at the Middle Slope, particularly for smaller trees, while recruitment rates were lowest. As bamboo clumps were concentrated in this sector, the locally higher instability in the tree community probably resulted from the direct interference of bamboos. The density of bamboo culms in the upland forest was negatively correlated with the rates of tree recruitment and gain in basal area, and positively correlated with tree mortality rates. Bamboos therefore seemed to restrict the recruitment, growth and survival of trees.

Diet of the maned wolf (Chrysocyon brachyurus) and its role in seed dispersal on a cattle ranch in Brazil

The maned wolf Chrysocyon brachyurus is the largest canid inhabiting South America. Its geographic distribution includes the open fields of Brazil's central area, which is currently undergoing agricultural expansion. The diet of the maned wolf and its seasonal variation was determined on a dairy cattle ranch (Sao Luis farm, 566 ha) in the State of Minas Gerais, Brazil. From January to December faeces of the maned wolf were collected monthly (n = 150 scats; 397 food item occurrences). Twenty-nine taxa were identified from scats, 18 of animal origin (46% or 183 occurrences) and 11 of plants (54% or 214 occurrences). The fruits of Solanum lycocarpum were the dominant food item in our study (29%). Mammals contributed 13%, arthropods 12%, birds 11% and reptiles 2% of the food items. Arthropods and fruits were prevalent in the rainy season and mammals in the dry season. As expected for a heavily fanned region, frugivory results were at the lower end of the diversity scale (9-33 species) and included four old garden species. No previous study of the diet of maned wolf has registered as many species of Solanaceae as this one. Although dietary richness was lower, the main food items (wolf fruit, armadillos, rodents, birds) were the same as study sites in 'cerrado' and upland meadows. In this region, the open habitats occupied by the maned wolf were previously covered by Atlantic forest, suggesting that landscape modification such as cattle ranching has opened new frontiers for distribution expansion of the maned wolf. The impact of loss of dietary richness and the increase in Solanaceae on the survival of the maned wolf need to be evaluated.

Diet of the maned wolf, Chrysocyon brachyurus (Mammalia : Canidae), during wet and dry seasons at Ibitipoca State Park, Brazil

Analysis of 141 seats of maned wolf Chrysocyon brachyurus collected in a region of upland forest and meadows of south-eastern Brazil yielded 351 food items in the wet season (60 seats) and 407 in the dry season (81 seats). Scarabaeidae and rodents were the most frequent animal food in both seasons, complemented by birds in the wet season and unidentified mammals in the dry season. Seeds revealed Solanum lycocarpum to be the most frequent plant food in the dry season and an Annonaceae and a Cactaceae the most frequent in the wet season. A total of 33 seed morphospecies were retrieved. Although our results reveal some shared and some divergent trends from dietary studies undertaken in savanna ('cerrado') areas, we found a very high frequency of potentially harmful tourists' garbage. This highlights the necessity for better environmental education and confirms that the maned wolf is a generalist and opportunist omnivore.

Unpalatability of Hyla semilineata tadpoles (Anura) to captive and free-ranging vertebrate predators

This study examines the unpalatability of Hyla semilineata tadpoles, relating this possible defence mechanism to their black, presumably aposematic, colouration. Bullfrog tadpoles (Rana catesbeiana), similar in size to the H. semilineata larvae, were used as controls in the experiments. The palatability of H. semilineata tadpoles was tested by offering the tadpoles to Fish (Hoplias malabaricus), free-ranging passerine birds (Pitangus sulphuratus) and hawks (Buteo magnirostris), and domestic chickens (Gallus domesticus). All predators showed a significant preference towards the control R. catesbeiana tadpoles. However, in experiments with fish, this preference was not significant for tadpole capture, only for their ingestion, suggesting that the fish could not distinguish between the two species before tasting them. Although great kiskadees (P. sulphuratus) preferred the control R. catesbeiana tadpoles, they promptly ingested more than half of the test H. semilineata tadpoles when these were offered alone. The chickens, used as naive predators, clearly learned to avoid the black H. semilineata tadpoles after a few trials. The conspicuous colouration and unpalatability of H. semilineata tadpoles may benefit the individual as well as the group, depending on the predator involved.

Aproveitamento de um fosfato natural parcialmente solubilizado pelas culturas do arroz, milho e soja: I. Resultados preliminares

Em solos pouco ��cidos, pobres em P dispon��vel, dois dos quais anteriormente com vegeta����o de cerrado, foram conduzidos ensaios destinados a comparar a efici��ncia de um fosfato natural parcialmente acidulado com ��cido sulf��rico (FAPS) com a do super simples (SS) e a do fosfato de Arax�� original. Usaram-se as culturas de arroz de sequeiro, milho e soja. Verificou-se que: (1) o FAPS deu produ����es que n��o diferiram estat��sticamente das obtidas com o SS sendo maiores que as conseguidas com o FA; (2) os resultados das an��lises de solos e da diagnose foliar indicam que o FAPS funcionou como fonte de P, Ca e S.

Matointerfer��ncia em arroz de sequeiro. I: efeitos do espa��amento e da aduba����o nitrogenada nas concentra����es de nutrientes no arroz e nas plantas daninhas

O trabalho insere-se num estudo global sobre os efeitos do espa��amento entre sulcos de semeadura e da dose de aduba����o nitrogenada sobre as rela����es competitivas entre a cultura do arroz de sequeiro (Oryza sativa L.) e uma comunidade de plantas daninhas. Para tanto, os tratamentos foram dispostos num esquema fatorial 2x2x3, onde constituiram vari��veis: duas condi����es de manejo da comunidade infestante - sem controle e com controle do mato durante todo o ciclo do arroz - dois espa��amentos entre sulcos de semeadura - 0,40 e 0,60 m - e tr��s doses de nitrog��nio - 2,4, e 7,2 de N/m de sulco. O experimento foi montado sobre solo Latossolo Vermelho Escuro fase arenosa e obedeceu o delineamento experimental de blocos ao acaso com 4repeti����es. Foram realizadas duas avalia����es: por ocasi��o do perfilhamento e por ocasi��o do florescimento da cultura. em compara����o com as plantas daninhas, os teores de N, P, Fe, Mn e Zn foram mais elevados no arroz; os de Ca e Mg foram menos elevados e os teores de K e Cu foram inferiores aos de D. horizontalis e superiores aos de 7. hirsuta. Por ocasi��o do florescimento, o arroz apresentou teores mais elevados de P, Cu, Mn e Zn, enquanto que a comunidade infestante apresentou maiores teores de N, K, Ca, Mg e Fe. Os efeitos do espa��amento e da fertiliza����o nitrogenada apresentaram aspectos distintos de acordo com o nutriente, a esp��cie envolvida e a ��poca da avalia����o. de um modo geral, os efeitos das plantas daninhas foram mais acentuados no espa��amento de 0,60 m.

Tectonic history and the biogeography of the freshwater fishes from the coastal drainages of eastern Brazil: an example of faunal evolution associated with a divergent continental margin

As drenagens costeiras do leste do Brasil correspondem a ��reas de grande significado biogeogr��fico, apresentando um alto grau de endemismo em sua fauna de peixes. Padr��es filogen��ticos sugerem uma rela����o pr��xima entre os rios que correm para o Atl��ntico a os adjacentes das terras altas do escudo cristalino. Entretanto, pouco tem sido dito sobre a din��mica dos processos geol��gicos relacionados aos eventos cladogen��ticos entre estas ��reas. Padr��es de distribui����o e filogen��ticos sugerem uma ��ntima associa����o com a hist��ria geol��gica da margem continental passiva da Am��rica do Sul, desde o Cret��ceo aos dias atuais. Soerguimentos macrod��micos, rifteamento, movimentos verticais entre blocos falhados e o recuo erosivo da margem leste sul-americana s��o considerados como as principais for��as geol��gicas atuando sobre a distribui����o da ictiofauna de ��gua doce nestas ��reas. A atividade tect��nica associada �� ruptura do Gondwana e separa����o da Am��rica do Sul e ��frica criou seis megadomos que s��o respons��veis por configurar a maior parte do atual curso das principais bacias hidrogr��ficas do escudo cristalino. Com exce����o das bacias localizadas ��s margens de tais megadomos, estes rios desenvolveram longos e sinuosos circuitos sobre o antigo escudo cristalino brasileiro antes de desaguarem no ent��o recentemente aberto Oceano Atl��ntico. Eventos cladogen��ticos iniciais entre drenagens de terras altas do escudo cristalino e tribut��rios do Atl��ntico podem estar associados com processos vicariantes desta fase inicial, e alguns t��xons antigos, basais, grupos-irm��o de t��xons muito inclusivos e de ampla distribui����o s��o encontrados nestas bacias hidrogr��ficas. Mais tarde, a denuda����o erosiva generalizada resultou em um ajuste isost��tico da margem leste da plataforma. Tal ajuste, concomitantemente a reativa����es de antigas zonas de falha, resultou em movimentos verticais entre blocos falhados, dando origem, no sudeste do Brasil, a bacias tafrog��nicas. Tais bacias, como a de Taubat��, S��o Paulo, Curitiba e Volta Redonda, entre outras, capturaram drenagens e fauna de terras altas adjacentes. Os peixes f��sseis da Forma����o Trememb�� (Eoceno-Oligoceno da Bacia de Taubat��) exemplificam este processo. Outros sistemas tafrog��nicos de idade Terci��ria foram tamb��m identificados em outros segmentos da margem continental Atl��ntica, como na Prov��ncia Borborema, no NE do Brasil, com marcada influ��ncia sobre o padr��o de drenagem. Ao mesmo tempo, o recuo erosivo da margem leste da plataforma capturou sucessivamente rios de planalto, os quais se tornaram tribut��rios atl��nticos, evoluindo associados aos principais sistemas de falha. A natureza continuada destes processos explica os padr��es filogen��ticos e de distribui����o miscigenados entre os tribut��rios atl��nticos e as terras altas do escudo cristalino adjacente, especialmente na margem sudeste do continente, representados por sucessivos, cada vez menos inclusivos, grupos irm��os, associados a eventos cladogen��ticos desde o final do Cret��ceo ao presente.

Produtividade do arroz de terras altas em fun����o do manejo do solo e da ��poca de aplica����o de nitrog��nio

O manejo adequado do solo e a identifica����o da ��poca de aplica����o de N podem aumentar, significativamente, a produtividade do arroz de terras altas. Neste contexto, objetivou-se, com este trabalho, avaliar a intera����o do manejo do solo com a ��poca de aplica����o de nitrog��nio, no desenvolvimento e produtividade da cultura. O delineamento experimental utilizado foi o de blocos ao acaso, em esquema fatorial 5x2, sendo 5 tipos de manejo do solo (arado de aiveca e grade niveladora; grade aradora e grade niveladora; escarificador tipo matabroto; SPD; e Aeromix - equipamento de escarifica����o superficial) e duas ��pocas de aplica����o de nitrog��nio (todo N na base, sendo 45 kg ha-1 de nitrog��nio aplicados com adubadora de tra����o mec��nica, 1 dia antes da semeadura do arroz, + 45 kg ha-1 de nitrog��nio aplicados no ato da semeadura; e 45 kg ha-1 de nitrog��nio aplicados no ato da semeadura + 45 kg ha-1 aplicados no in��cio do perfilhamento das plantas), com 4 repeti����es. N��o houve intera����o dos fatores, para a vari��vel estande final de plantas. Nos tratamentos onde houve revolvimento de solo com arado de aiveca e grade, observou-se maior produtividade quando o nitrog��nio foi parcelado. Quando o nitrog��nio foi aplicado todo no plantio, o tratamento com escarificador tipo matabroto apresentou a maior produtividade, diferindo de todos os outros tratamentos. O plantio convencional (aiveca ou grade) apresentou produtividade semelhante ao SPD, quando se aplicou o N todo no plantio.

Desenvolvimento e produtividade de cultivares de arroz de terras altas em fun����o do manejo do solo

A identifica����o de cultivares, para cada tipo de manejo do solo, pode favorecer o aumento da produtividade da cultura do arroz de terras altas. Neste contexto, objetivou-se, com este trabalho, estudar o desempenho de gen��tipos de arroz de terras altas, em dois sistemas de manejo do solo: preparo convencional (PC) e sistema plantio direto (SPD). O estudo foi desenvolvido no munic��pio de Ipameri, GO, em 2008/2009. O delineamento experimental foi em blocos ao acaso, no esquema fatorial 2x8, com dezesseis tratamentos e quatro repeti����es. O primeiro fator foi o sistema de manejo do solo (PC e SPD) e o segundo cultivares (BRS Curinga, BRS Primavera, BRS Monarca, BRS Pepita, BRS Sertaneja, Caraj��s, Caiap�� e Bonan��a). As plantas apresentaram-se mais altas no PC do que no SPD. Quanto ao n��mero de perfilhos por planta, verificou-se, tamb��m, variabilidade nas cultivares, quanto ao tipo de manejo de solo. Constatou-se que o preparo convencional propiciou maiores produtividades (m��dia de 4.349 kg ha-1 que o sistema plantio direto (m��dia de 3.521 kg ha-1, sendo o n��mero de pan��culas por mI;e n��mero de gr��os por pan��cula os componentes de produ����o que mais contribu��ram para esta diferen��a. Todas as cultivares apresentaram diferen��as estat��sticas entre os dois sistemas de manejo do solo, com exce����o da cultivar Caiap��. Nos dois sistemas, Caraj��s foi a mais produtiva e diferiu, estatisticamente, das cultivares BRS Sertaneja e BRS Primavera.