Silicate fertilizer and irrigation depth in corn production

Calcium-magnesium silicates improve the soil physicochemical properties and provide benefits to plant nutrition, since they are sources of silica, calcium and magnesium. The objective of this study was to evaluate the grain yield of irrigated corn fertilized with calcium-magnesium silicate. The experiment was carried out in a greenhouse in Campina Grande - PB, Brazil, using plastic pots containing 80 kg of soil. The treatments consisted of the combination of four irrigation depths, related to water replacement of 50, 75, 100 and 125% of the crop evapotranspiration, with fertilizer levels of 0, 82, 164 and 246 g of calcium-magnesium silicate, with three replications. The experimental design was in randomized blocks, with the irrigation depths distributed in bands while the silicon levels constituted the subplots. Corn yield was influenced by calcium-magnesium silicate and by irrigation depth, obtaining the greatest grain yield with the dose of 164 g pot-1 irrigated at the highest water level. The water-use efficiency of in corn production tended to decrease when the irrigation depth was increased. The best water-use efficiency was observed when the irrigation level was between 87 and 174 mm, and the dose of silicate was 164 g pot-1.

Vegetation near Santa Teresinha, NE Mato Grosso.

The Santa Tenesinha region in northeaster Mato Grosso has a varied vegetation which is principally hammock pantanal. The flat clayey alluvial ground between the hummocks is coveted with a continuous non-cerrado ground cover dominated by grasses but which harbors sedges and a lange herb flora. No woody plants grow in it. The tops of the 10-20m wide, slightly elliptical hummocks, 1.5-2 m high, 10-40 per hectare, are covered with cerrado plants: herbs, semlshrubs, thin- and thick-stemmed shrubs and low trees. For 4-5 months during the latter part of the rainy season, the regional water table rises to the surface and the ground between the hummocks becomes saturated or floods up to 1.5-2 m deep. The tops of the hummocks almost always remain above high water level. In the dry season the surface soil dries out completely. This alternation of saturation or shallow flooding and dryness, prevents woody plant, growth between the hummocks, and except for a few tolerant species, also prevents woody plant. growth on the lower part of the hummochs. The gallery forests in the pantanal are seasonally flooded more deeply but their soil does not dry out so thonoughly in the dry season so woody plant growth is not prevented.

Respiratory characteristics of Hoplostenum littorale (Siluriformes, Callichthyidae)

Hematological parameters, intraerythrocytic phosphates, hemoglobin, and whole blood Bohr effect of the South American armored catfish Hoplostenum littorale were studied during different seasons of the year. In addition, the degree of dependence on air breathing was determined for this species. The hematological parameters presented seasonal variations, which were not correlated to oxygen, temperature, and water level oscillations. Five anodic hemoglobin fractions were detected in starch gel electrophoresis. In addition to ATP, GTP and Fe-GTP being detected, 2,3-DPG was also detected in red blood cells of H. littorale. The latter is an intraerythrocytic phosphate characteristic to red blood cells of mammalians. The increased production of 2,3-DPG could be associated with decreasing Hb-O2 affinity and both features could be related to environmental temperature increase. Whole blood Bohr effect was influenced by water temperature. This study confirms H. littorale to be continuous and not obligate air breather, under all dissolved oxygen level conditions.

Geological control of Podocnemis expansa and Podocnemis unifilis nesting areas in Rio Javaés, Bananal Island, Brazil

The distribution of the nests of Podocnemis expansa (Amazon turtle) and Podocnemis unifilis (yellow-spotted side neck turtle) along the point bars of the Javaés River in Bananal Island, demonstrates a clear preference of these chelonians for differentiated geological environments, in respect to the morphology, grain size or height of the nests in relation to the level of the river. The topographical distribution and the differences in the grain size of the sediments that compose the point bars of the river, originated from the multiple sedimentary processes, and make possible the creation and separation of different nesting environments. Each turtle species takes advantage of the place that presents physiographic characteristics appropriate to the hatching success of their eggs. The superposition of the P. expansa and P. unifilis nest placement areas is rare. The P. expansa nests are concentrated on the central portion of the beaches where successive depositional sedimentary events produced sandy banks more than 3.3 m above the river water level. The P. unifilis nests are distributed preferentially in the upstream and downstream portions along the point bars where the sandy deposits rarely surpass 1.5 m at the moment of laying. P. expansa nests located on the beaches of fine to medium sized sand hatch in a mean of 68 days, while those incubated on beaches of medium to coarse sand size take a mean of 54 days to hatch.

Treetop shelter of a neotropical river otter cub (Lontra longicaudis - Carnivora: Mustelidae) in an Amazonian flooded forest

The finding of a Neotropical river otter (Lontra longicaudis) cub occupying a shelter in a hollowed treetop is reported. The observation was made in a seasonally flooded forest in Central Amazonia, during the high water peak of the annual inundation cycle. A literature review indicates that this is the first description of a shelter of the species, both in a hollowed tree and in Amazonia. This observation can indicate a strong relationship between the species' breeding cycle with the annual dynamics of Amazonian rivers. We discuss potential advantages and disadvantages of breeding when water level is high.

Quantitative fidelity of recent freshwater mollusk assemblages from the Touro Passo River, Rio Grande do Sul, Brazil

This study represents one of the first contributions to the knowledge on the quantitative fidelity of the recent freshwater molluscan assemblages in subtropical rivers. Thanatocoenoses and biocoenoses were studied in straight and meandering to braided sectors, in the middle course of the Touro Passo River, a fourth-order tributary of the Uruguay River, located in the westernmost part of the State of Rio Grande do Sul. Samplings were carried out through quadrats of 5 m², five in each sector. A total area of 50 m² was sampled. Samplings were also made in a lentic environment (abandoned meander), with intermittent communication with the Touro Passo River, aiming to record out-of-habitat shell transportation from the lentic communities to the main river channel. The results show that, despite the frequent oscillation of the water level, the biocoenosis of the Touro Passo River shows high ecological fidelity and undergoes little influence from the lentic vicinal environments. The taxonomic composition and some features of the structure of communities, especially the dominant species, also reflect some ecological differences between the two main sectors sampled, such as the complexity of habitats in the meandering-sector. Regarding the quantitative fidelity, 60% of the species found alive were also found dead and 47.3% of the species found dead were also found alive, at river-scale. However, 72% of the dead individuals belong to species also found alive. This value might be related with the good rank order correlation obtained for live/dead assemblages. Consequently, the dominant species of the thanatocoenoses could be used to infer the ecological attributes of the biocoenoses. The values of all the indexes analyzed were very variable in small-scale samplings (quadrat), but were more similar to others registered in previous studies, when they were analyzed in a station and river scale.

Trophic ecology and the use of shelters and latrines by the Neotropical otter (Lontra longicaudis) in the Taquari Valley, Southern Brazil

This manuscript presents information about the ecology of Lontra longicaudis (Olfers, 1818) in the Taquari Valley, State of Rio Grande do Sul, southern Brazil. The study was carried out in two areas located in the Forquetinha Creek and in the Forqueta River from January to December 2003. The otters are specialist feeders (Bsta = 0.24), with a diet based mostly on fish, especially those of the families Loricariidae and Cichlidae. Most shelters used by the species were excavated burrows underneath tree roots, while shelters within rocks were used less frequently. The burrows showed great variation in size, being found on average 3.5 m (sd = 3.6 m) away from the margin and 2.5 m (sd = 1.2 m) above the water level. Scent marks were made preferentially on rocks and fallen tree trunks at the edge of the water. There was a tendency to increase the reutilization of latrines in detriment of using new sites throughout the sample period.

First records of Freshwater Bivalves of Ilha Grande National Park, Paraná, Brazil

The Ilha Grande National Park, Paraná, Brazil, is located in the Upper Paraná River and has characteristics typical of a floodplains. This protected area includes lagoons connected and disconnected to the Paraná River, although the latter also connect during periods of high water level, thus composing a heterogeneous group of lacustrine environments. The enormous potential the flora and fauna diversities are still little known to the region, as can be seen through benthic invertebrates, inclunding bivalves mollusks. The granulometric composition of these floodplain lagoons was formed mainly by mud and very fine sand. Furthermore, organic matter composition was predominantly of fine particulate. The other abiotic factors differed from lagoons located within the island of the park to those located in the left margin of Paraná River. The results demonstrated the importance of abiotic factors such as the physical composition of granulometric texture, organic matter and macrophyte banks, to the establishment of bivalves in these floodplain lagoons. We recorded bivalves of Pisidium (native), Diplodon (native), and Corbicula (invasive). The highest values of Diplodon sp. density were observed at São João/C lake, for Pisidium sterkianum (Pilsbry, 1897) at São João/M lake, and to Jatobá/C lagoon with high density of invasive species Corbicula fluminea (Müller, 1774). This study to obtain conduct the first records of freshwater bivalves in floodplains lagoon in the Ilha Grande National Park, and provides contributions to better understanding the ecology of these mollusks. The recording of native species in the region of Upper Paraná River floodplain after a lomg period without new records, demonstrated the importance of protecting the lagoons of the Ilha Grande National Park as they can be a possible refuge to some species of native freshwater bivalves.

Diverse population dynamics of three Anopheles species belonging to the Triannulatus Complex (Diptera: Culicidae)

The Triannulatus Complex of Anopheles (Nyssorhynchus) consists of at least three sibling species, namely Anopheles triannulatus s.s., Anopheles halophylus and a third undescribed member herein referred to as An. triannulatus "C". Sympatric anophelines belonging to species complexes, even though closely related, may exploit different environments such as larval habitats. In this paper we hypothesize that rainfall and seasonal flooding would distinctly influence the availability of larval habitats and consequently the seasonal population dynamics of sympatric members of the Triannulatus Complex. A reflection of this is distinct seasonal biting frequencies exhibited by three members of the Triannulatus Complex at a site in Central Brazil. Population dynamics seem to be influenced by the water level in the local rivers, although biting frequency of all three species was negatively influenced by rainfall. An. triannulatus s.s. was more abundant following the end of the rainy season, but notably 30 to 60 days after flooding. On the other hand, An. halophylus and An. triannulatus C peaked during the middle of the dry season, when water impoundments have no inflow, are somewhat reduced in size and the water becomes brackish. Differences in population dynamics were greater between An. triannulatus s.s. and An. halophylus and An. triannulatus C than between An. halophylus and An. triannulatus C. This might reflect differences in larval habitat exploitation and therefore spatial segregation among these members of the complex.

Orthoptera assemblages associated with macrophytes of floodplain lakes of the Paraná River

Orthoptera assemblages associated with macrophytes of floodplain lakes of the Paraná River. The Orthoptera assemblage composition varies considerably, depending on habitat type. This study examines the spatiotemporal relationship between plant diversity, hydrometric level, environmental variables and the Orthoptera richness and abundance in floodplain lakes connected permanently or temporarily with the main channel of the Paraná River. The grasshoppers were collected fortnightly (April 2006May 2007). A total of 17 species were recorded and classified according to their frequency of occurrence in constant (7), accessory (4), or accidental (6) species. In the two lakes, the greater species richness and abundance was recorded in summer, thereby coinciding with the highest water level of the Paraná River. The most significant correlation between the orthopteran richness and abundance was with the water level. The aquatic plant richness was significantly different between the lakes, but the vegetation was dominated by Eichhornia crassipes (Mart.) Solms. (Liliales, Pontederiaceae). The lake, which was connected permanently, presented the highest values of diversity and abundance, proving to be a more diverse assemblage. The beta diversity was higher in the temporary connected lake than in the permanently connected one. The orthopterans assemblages were different between the lakes, Cornops aquaticum and Tucayaca gracilis were the species that contributed more to the level of dissimilarity. C. aquaticum was more representative in the lake temporarily connected, while T. gracilis in the permanent connected one. The water level of the Paraná River and the connectivity of the floodplain lakes play an important role to explain the abundance and richness of their orthopteran assemblages.

Pequisas físicas e químicas do sistema hidrográfico da região lagunar de Cananéia: I - Cursos de águas

The present elaboration is a "previous note" about two watercourses, Maria Rodrigues and Baguaçú, belonging to Hydrografic System of the Cananeas Lagoon Region in the Southern Part of it he Coast of the Estado de São Paulo, Brazil, which is the objete of our physical and chemical researches. It is based on the first results obtained from our contact with that region, ttfie studies of which are being continued and will still have to confirm or not the previous conclusions, which we are presenting in this "provisional paper". We studied the Maria Rodrigues and the Baguacu under the discussion whether they are to be clasified as a river in the poper sense ot the word or waUer-courses of any other origin. For this purpose we established observatory-stations along their whole course where we collected quantities of water to be analised. The data included in the table nº 1 and 2 refer to the physical and chemical properties of these portions of water. These physical and chemical properties were discussed and compared one with the other according to the observatory-stations, at the same moment and the tide predominating on that occasion. The physical and chemical datas were obtained according to the norms recommended by the Conseil International permanent pour l'Exploration de la Mer, Copenhague. We also presented a sketch of both; we described their relations with regard to the Mar de Cananéia; we inserted comprehensible histograms of the distribution of the observatory-stations, each of them with the respective indices, and at last we tried to correlate the occurrence of the "plancton" with the physical and chemical properties of water as well in the Maria Rodrigues as in the Baguacú. From these researches result the following previous conclusions: 1 - By the data obtained up to now nothing could be formulated as to a cyclical or "seasonal" aspect. 2 - By the comparison of the phenomena which present the rivers in the proper sense of the word and those observed in the Maria Rodrigues and the Baguacú, we are convinced that both are water-courses of the classical type "marigot,". 3 - Their channels are maintained open by the effect of the tide and, more perphaps, by the infiltration-water deriving from the underground-water level owing to the type of the soil of that region, which in mean shows an elevation of 2-4 meters over sea-level. 4 - From tables 1 and 2 and histograms 2 and 3 we stated that the water, not only of the Maria Rodrigues but also of the Baguacú, conserve more or less the same physical and chemical properties, provided that: 1) the localities to be compared are the mouths or equidistant points from them in the lower course, and 2) the moment and tide must be the same. Tables 3a and 3b show sufficiently this supposition.

Estimation of alluvial recharge in the semiarid

In areas where there is irrigated agriculture, the recuperation of water reserves in alluvial aquifers may occur preferentially due to precipitation. Recharging can be evaluated from variation information of water depth measured in piezometers or observation wells. Thus, the aim of this research is to study the recharge in the alluvial aquifer formed by the Mimoso temporary stream in the semiarid region of Pernambuco (PE), Brazil, using the method of the fluctuation of the water level. This system is typical on the Brazilian Northeast semiarid region, using groundwater for domestic supply and for irrigation on small scale agriculture. Monthly potentiometric levels and rainfall data were used. The selected period for the study, from January 2002 to October 2009, involved extreme events of flooding and droughts as well as regular years, providing a better understanding of the behavior of the alluvial recharge. It was found that the system responds significantly to precipitation events. It was also observed that even with different soil textures in the study area, recharge factors were not significantly different. The study provided a better understanding of the behavior of aquifer recharge and its relationship with the soil and the rainfall events in the region.

The coastal restinga vegetation of Pará, Brazilian Amazon: a synthesis

The present article reviews studies (some unpublished) of the vegetation of coastal sandy soils (restinga) along the coast of Pará State, northern Brazil. A total of 411 higher plant species are reported; Fabaceae, Poaceae, Cyperaceae, Rubiaceae and Myrtaceae are the most species-rich families. Nearly half of the restinga species (48%) are terrestrial herbs; palms, trees and shrubs account for 39% of the species, the remainder being lianas and epiphytes. Species are frequently wide-spread and occur in coastal areas of Southeastern Brazil as well as at inland sites in the Amazon region. Only two species appear to be exclusively coastal; whereas other species appear to exhibit a preference for sandy soils. Plant assemblages are commonly classified by means of "formations" associated with certain habitats but current data do not allow the description of well-defined plant associations. The species composition at different sites along the Pará coast does not show any clear regional grouping pattern. Seasonal changes in the composition of restinga vegetation are most probably linked to variation in ground water level. Restinga forest is mostly low and open; among the dominant tree species are Humiria balsamifera Aubl., Pouteria ramiflora (Mart.) Radlk., Anacardium occidentale L., Byrsonima crassifolia (L.) Kunth, and Tapirira guianensis Aubl.

Subgeneric diversity of Brasilonema (Cyanobacteria, Scytonemataceae)

The recently described scytonematoid cyanobacterial genus Brasilonema is known mainly from tropical and subtropical rain forests (Mata Atlântica) of southeastern Brazil, where it occurs in aerophytic wooden, stony and iron substrates. This genus was defined according to both molecular and morphological criteria. The type species B. bromeliae was described from the specialized habitat: it grows in phytothelmes, epiphytic on both living and died leaves within the rosettes of large bromeliad plants slightly above or in the zone of the water level. The genus Brasilonema is evidently widely distributed in coastal forests of São Paulo State, where it occurs also in remarkable diversity. According to our results, this genus currently comprises seven taxa, which are distinct by different morphology and ecological characteristics.

A municipal level approach to the management of schistosomiasis control in Peri-Peri, MG, Brazil

A schistosomiasis control program was implemented between 1974/87 in Peri-Peri,. MG (622 inhabitants). Molluscicide (niclosamide) was applied at three monthly intervals in water sources with Biomphalaria glabrata, and individuals eliminating Schistosoma mansoni eggs in the feces were treated annually with oxamniquine. From 1974 to 1983 the control measures were undertaken by staff of the "René Rachou" Research Center FIOCRUZ (CPqRR), and from 1984 to 1987 these measures were included in the Capim Branco basic health network activities. During both periods, the prevalence, incidence, intensity of infection and hepatosplenic form as well as the number of infected snails decreased significantly. The prevalence decreased from 43.5 to 4.4%, the incidence from 19.0 to 2.9%, the overall intensity of S. mansoni from 281 to 87 and of the hepatosplenic form from 5.9 to 0.0%. The results obtained suggest that the municipal management of control measures was as effective as the vertical program conducted by CPqRR staff.