Effect of cattle manure on sunflower production and water use in two types of soil

The aim of the present study was to evaluate water consumption, use efficiency and yield components of sunflower variety Embrapa 122 V/2000 cultivated in two types of soil (Fluvissol and Haplic Luvisol) subjected to increasing doses of cattle manure. The experiment was carried out in a greenhouse at Universidade Estadual da Paraíba. The experimental design was completely randomized in a factorial scheme. The irrigation was performed every other day, replacing the water absorbed by the plants. The water consumption and the use efficiency were evaluated, being the use efficiency determined by the ratio of the total dry mass of sunflower and the amount of water used to produce it in each treatment. Plants were harvested at 95 days after sowing when the following parameters were evaluated: number of seeds per plant, weight of seeds per plant, weight of 1000 seeds and the outer diameter of the capitulum (head). The results showed that the sunflower was positively affected by cattle manure application, increasing the production components and the water use efficiency, regardless of the type of soil. Excepting for the 1000 seeds weight and the water use efficiency, the type of soil affected significantly the water use, the number and weight of seeds per plant. The plants cultivated in Haplic Luvisol had a better performance.

Efficiency of water use in sunflower grown in hydroponic system under saline stress

In order to identify alternatives for the use of saline water in agricultural production, the effects of the use of brackish water in the preparation of the nutrient solution for the cultivation of sunflower (cv. EMBRAPA 122-V2000) were studied in hydroponic system on consumption and efficiency of water use for the production of achenes and biomass. A completely randomized design was used, analyzed in a 5x2 factorial scheme with three replications. The factors studied were five levels of salinity of nutrient solution (1.7 - control; 4.3; 6.0; 9.0; and 11.5dS m-1) and two plant densities - one or two plants per vessel. It was concluded that the water consumption of sunflower is a variable sensitive to the salinity of the nutrient solution, especially after the fourth week of crop, and that the efficiency of water use in the production of achenes and biomass of sunflower is greater when the plant density increases from one to two plants per vessel, even under saline stress.

Morphological, physical and pedogenetic attributes related to water yield in small watersheds in Guarapari/ES, Brazil

Soil characteristics related to the genesis, land use and management are important factors in water dynamics in watersheds. This study evaluated physical, morphological and pedogenetic attributes related to water yield potential in small watersheds in Guarapari, ES, Brazil. The following representative profiles were selected, morphologically described and sampled in area of Atlantic Forest domain: Lithic Udifolists, Oxyaquic Udifluventes, Typic Paleudults, Typic Hapludults, Typic Hapludox, Oxic Dystrudepts and Typic Endoaquents. Samples were collected in the soil profiles for physical analysis. Measurements of field-saturated hydraulic conductivity and soil penetration resistance were perfomed in some profiles, which were under different uses. The Endoaquents of Limão Creek can be considered efficient as temporary water reservoirs. However, the use of artificial drainage tends to reduce this effect. Differential erosion was detected by the sand texture on the surface of the Typic Paleudults due to the low degree of clay flocculation, slope, high resistance to the penetration and low hydraulic conductivity of the Bt horizon, making it necessary to adopt soil management practices to increase the water infiltration. Under pasture, mainly in the cattle trails where the trampling is more intense, there was high resistance to penetration in the superficial layers of the Typic Hapludults. The Typic Hapludox have the greatest potential for water yield in the small watersheds because of its greater extent in the headwaters and their morphological and physical characteristics, which can result in increased aquifer recharge.

Spatial and temporal evolution of family-farming land use in the Tapajós region of the Brazilian Amazon

Pressures on the Brazilian Amazon forest have been accentuated by agricultural activities practiced by families encouraged to settle in this region in the 1970s by the colonization program of the government. The aims of this study were to analyze the temporal and spatial evolution of land cover and land use (LCLU) in the lower Tapajós region, in the state of Pará. We contrast 11 watersheds that are generally representative of the colonization dynamics in the region. For this purpose, Landsat satellite images from three different years, 1986, 2001, and 2009, were analyzed with Geographic Information Systems. Individual images were subject to an unsupervised classification using the Maximum Likelihood Classification algorithm available on GRASS. The classes retained for the representation of LCLU in this study were: (1) slightly altered old-growth forest, (2) succession forest, (3) crop land and pasture, and (4) bare soil. The analysis and observation of general trends in eleven watersheds shows that LCLU is changing very rapidly. The average deforestation of old-growth forest in all the watersheds was estimated at more than 30% for the period of 1986 to 2009. The local-scale analysis of watersheds reveals the complexity of LCLU, notably in relation to large changes in the temporal and spatial evolution of watersheds. Proximity to the sprawling city of Itaituba is related to the highest rate of deforestation in two watersheds. The opening of roads such as the Transamazonian highway is associated to the second highest rate of deforestation in three watersheds.

Coffee water use in agroforestry system with rubber trees

Water uptake and use by plants are essentially energy processes that can be largely modified by percentage of soil cover, plant type; foliage area and its distribution; phenological stage and several environmental factors. Coffee trees (Coffea arabica - cv. Obatã IAC 1669-20) in Agrforestry System (AFS) spaced 3.4x0.9m apart, were planted inside and along rows of 12- year-old rubber trees (Hevea spp.) in Piracicaba-SP, Brazil (22 42'30" S, 47 38'00" W - altitude: 546m). Sap flow of one-year-old coffee plants exposed to 35; 45; 80; 95 and 100% of total solar radiation was estimated by the heat balance technique (Dynamax Inc.). Coffee plants under shade showed greater water loss per unit of incident irradiance. On the other hand, plants in monocrop (full sun) had the least water loss per unit of incident irradiance. For the evaluated positions average water use was (gH2O.m-2Leaf area.MJ-1): 64.71; 67.75; 25.89; 33.54; 27.11 in Dec./2002 and 97.14; 72.50; 40.70; 32.78; 26.13 in Feb./2003. This fact may be attributed to the higher stomata sensitivity of the coffee plants under more illuminated conditions, thus plants under full sun presented the highest water use efficiency. Express transpiration by leaf mass can be a means to access plant adaptation to the various environments, which is inaccessible when the approach is made by leaf area.

SELECTION OF HERBICIDES TARGETING THE USE IN CROP SYSTEMS CULTIVATED WITH SHOWY CROTALARIA

ABSTRACT The increase in the area planted with Crotalaria spectabilishas occurred by several factors, highlighting the potential to reduce the nematodes, nitrogen fixation and the high production of biomass. By becoming a species sown as a crop, it is necessary to control the weeds that coexist with showy crotalaria. This change in the use of this crop creates the possibility of this specie becoming a weed. The aim of this study was to assess the potential use of herbicides applied in preemergence and postemergence of C.spectabilisfor different purposes (control of volunteer and selectivity plants). Three experiments were installed in a greenhouse (two with herbicides applied in preemergence - in soils with distinct textural categories; and one experiment with herbicides applied in postemergence). The results of the experiments with herbicides applied in preemergence showed that: amicarbazone, atrazine, diuron, metribuzin, prometryn, fomesafen and sulfentrazone showed effectiveness for control of C.spectabilis in clayey soil. Besides these, flumioxazin and isoxaflutole also showed potential to be used in the control of showy crotalaria in soils with loam texture. In relation to the postemergence herbicides, atrazine, diuron, prometryn, flumioxazin, fomesafen, lactofen, saflufenacil, amonio-glufosinate and glyphosate can be used aiming the chemical control of C.spectabilis. Herbicides chlorimuron-ethyl, diclosulan, imazethapyr, pyrithiobac-sodium, trifloxysulfuron-sodium, clomazone, pendimethalin, S-metolachlor and trifluralin applied in preemergence, and imazethapyr, pyrithiobac-sodium, flumiclorac, bentazon and clethodim applied in postemergence caused low levels of injury to C.spectabilis plants, making necessary the development of new searches to ensure the selectivity of these products.

Age-specific Prevalence of Antibodies to Hepatitis A in Children and Adolescents from Rio de Janeiro, Brazil, 1978 and 1995: Relationship of Prevalence to Environmental Factors

The age-specific prevalence of antibodies to hepatitis A virus (anti-HAV) was determined in two different population groups with low socio-economic status from Rio de Janeiro city, Brazil, whose serum samples were collected 17 years apart (Population 1, 1978; Population 2, 1995). In Population 2, analysis of the anti-HAV prevalence was also carried out with respect to environmental factors. Population 1 was composed of 520 stored sera collected from the umbilical cord of term neonates and children aged 1 month to 6 years. In population 2, 720 serum samples were collected from children and adolescents with ages ranging from 1 to 23 years. The overall prevalence rate of anti-HAV in Population 1 and Population 2 was 65.6% and 32.1%, respectively. In Population 1, the anti-HAV prevalence reached 88% at the age of 3, while in Population 2, it increased from 4.5% in children under the age of 3 to 66% in the group of adolescents over the age of 14. The low exposure to HAV infection in younger children from Population 2 could be a result of improved environmental hygiene and sanitation, as demonstrated by the presence of piped water, waste and sewage disposal systems in most houses from this population group. These findings indicate a possible change in the prevalence of hepatitis A in Rio de Janeiro

Contribution of macroporosity to water flux of a soil under different tillage systems

In view of the importance of the macroporosity for the water transport properties of soils, its quantitative assessment is a challenging task. Measurements of hydraulic conductivity (K) at different soil water tensions and the quantification of water-conducting macropores (θM) of a soil under different tillage systems could help understand the effects on the soil porous system and related hydraulic properties. The purpose of this study was to assess the effects of Conventional Tillage (CT), Chisel Plow (CP) and No Tillage (NT) on θM and on K; and to quantify the contribution of macroporosity to total water flux in a loam soil. A tension disc infiltrometer was used at two soil water pressure heads (-5 cm, and 0) to infer θM and K, during fallow. Macroporosity was determined based on the flow contribution between 0 and -5 cm water potentials (K0, K5, respectively), according to the Hagen-Poiseuille equation. The K0 values were statistically higher for CT than for NT and CP. The K5 values did not differ statistically among treatments. The mean K values varied between 0.20 and 3.70 cm/h. For CT, θM was significantly greater than for CP and NT, following the same trend as K0. No differences in θM were detected between CP and NT. With CT, the formation of water-conducting macropores with persistence until post-harvest was possible, while under CP preparation, the water-conducting macropores were not persistent. These results support the idea that tillage affects the soil water movement mainly by the resulting water-conducting macropores. Future studies on tillage effects on water movement should focus on macroporosity.

Molecular biology of baculovirus and its use in biological control in Brazil

Baculoviruses are insect viruses found mainly in Lepidoptera. The family Baculoviridae is taxonomically divided in two genera, Nucleopolyhedrovirus and Granulovirus, which differ by occlusion body morphology. NPVs (Nucleopolyhedroviruses) have polyhedrical inclusion bodies (PIBs) containing multiple viral particles, while GVs (Granuloviruses) appear to be generally single particles occluded in oval shaped occlusion bodies. During the life cycle, two different viral progenies are produced: BV (Budded Virus) and PDV (Polyhedra Derived Virus), which are essential for the infectious process and virus propagation in host cells. Baculoviruses are being used for pest control and they are especially safe due to their specificity and invertebrate-restricted host range. Baculoviruses have been used as vectors for high level protein expression ofheterologous genes from prokaryotic and eukaryotic organisms. Also, recombinant DNA techniques have allowed the production of genetically modified viral insecticides. This study is a review on the taxonomy, structure, replication and molecular biology of baculoviruses, as well as their use as bioinsecticides in Brazil.

Produção de lipases de Aspergillus niger e Aspergillus fumigatus através de fermentação em estado sólido, avaliação da especificidade do substrato e seu uso em reações de esterificação e alcoólise: evaluation of substrate specificity and use in esterification and alcoholysis reactions

Filamentous fungi were cultured under solid state fermentation of soybean residues to produce lipases. Enzymes produced by Aspergillus niger esterified oleic and butyric acids in the presence of ethanol, while enzymes produced by Aspergillus fumigatus demonstrated no esterification activity toward lauric acid. In case of A. niger, direct lyophilization of fermented bran led to higher esterification activity. The esterification of oleic acid by enzymes of A. fumigatus was neither influenced by pH adjustment nor by the extraction process. Conversions to ethyl esters were higher after pH adjustment with lyophilized liquid extract of A. niger.

Potential of adjuvants to reduce drift in agricultural spraying

The reduction of pesticide spraying drift is still one of the major challenges in Brazilian agriculture. The aim of this study was to evaluate the potential of different adjuvant products, such as surfactants, drift retardants, mineral oil and vegetable oil for reducing drift in agricultural spraying. The experiment consisted of quantifying drift of sprayings of 18 adjuvants dissolved in water under controlled conditions in a wind tunnel. Tests were performed in triplicates with spraying nozzles type Teejet XR8003 VK, pressure of 200kPa and medium drops. Solutions sprayed were marked with Brilliant Blue dye at 0.6% (m v-1). The drift was collected using polyethylene strips transversally fixed along the tunnel at different distances from the nozzle and different heights from the bottom part of the tunnel. Drift deposits were evaluated by spectrophotometry in order to quantify deposits. The adjuvants from chemical groups of mineral oil and drift retardant resulted in lower values of drift in comparison with surfactants and water. The results obtained in laboratory show that the selection of appropriate class and concentration of adjuvants can significantly decrease the risk of drift in agricultural spraying. However, the best results obtained in laboratory should be validated with pesticide under field conditions in the future.

Risk factors and presence of antibodies to Toxoplasma gondii in dogs from the coast of São Paulo State, Brazil

Toxoplasmosis is caused by the obligate intracellular protozoan parasite Toxoplasma gondii and affects warm-blooded vertebrates, including pets and man. Dogs are epidemio-logically important since they act as sentinels for the infection in humans. The present study aimed to determine the presence of antibodies to T. gondii in 205 serum samples from dogs in Ubatuba, Sao Paulo state, Brazil, through indirect immunofluorescence reaction (IFAT), as well as the risk factors related to toxoplasmosis in the animals such as breed, age, sex, access to outdoors, homemade food ingestion, access to untreated water, and contact with rodents. Toxoplasmosis-positive samples accounted for 52/205 (25.4%), with titers ranging from 16 to 256. The serological results presented significant association (P<0.05) with homemade food ingestion (45/118; 38.1%; CI95% 29.9%-47.2%) (OR=7.0; CI95% 3.0-16.6), and with access to outdoors where those that do not have access to the street were prevalent (37/121; 30.6%; CI95% 23.1%-39.3%) (OR=0.5; CI95% 0.2-1.0). These results show that toxoplasmosis in this region is related to problems of sanitary education, mainly concerning the appropriate cooking of foods, since most positive animals did not show significant association with the presence of rodents or untreated water consumption but showed, instead association with ingestion of homemade food. Thus, toxoplasmosis is a public health problem in the studied region, and sanitary measures are needed to control the infection due to the strict relationship between man and dog and the presented risk factors

Rapid diagnosis of resistance to imidazolinone herbicides in barnyardgrass (Echinochloa crus-galli) and control of resistant biotypes with alternative herbicides

The resistance of barnyardgrass (Echinochloa crus-galli) to imidazolinone herbicides is a worldwide problem in paddy fields. A rapid diagnosis is required for the selection of adequate prevention and control practices. The objectives of this study were to develop expedite bioassays to identify the resistance to imidazolinone herbicides in barnyardgrass and to evaluate the efficacy of alternative herbicides for the post-emergence control of resistant biotypes. Three experiments were conducted to develop methods for diagnosis of resistance to imazethapyr and imazapyr + imazapic in barnyardgrass at the seed, seedling and tiller stages, and to carry out a pot experiment to determine the efficacy of six herbicides applied at post-emergence in 13 biotypes of barnyardgrass resistant to imidazolinones. The seed soaking bioassay was not able to differentiate the resistant and susceptible biotypes. The resistance of barnyardgrass to imidazolinones was effectively discriminated in the seedlings and tiller bioassays seven days after incubation at the concentrations of 0.001 and 0.0001 mM, respectively, for both imazethapyr and imazapyr + imazapic. The biotypes identified as resistant to imidazolinones showed different patterns of susceptibility to penoxsulam, bispyribac-sodium and pyrazosulfuron-ethyl, and were all controlled with profoxydim and cyhalofop-butyl. The seedling and tiller bioassays are effective in the diagnosis of barnyardgrass resistance to imidazolinone herbicides, providing an on-season opportunity to identify the need to use alternative herbicides to be applied at post-emergence for the control of the resistant biotypes.

A priori estimation of accuracy and of the number of wells to be employed in limiting dilution assays

The use of limiting dilution assay (LDA) for assessing the frequency of responders in a cell population is a method extensively used by immunologists. A series of studies addressing the statistical method of choice in an LDA have been published. However, none of these studies has addressed the point of how many wells should be employed in a given assay. The objective of this study was to demonstrate how a researcher can predict the number of wells that should be employed in order to obtain results with a given accuracy, and, therefore, to help in choosing a better experimental design to fulfill one's expectations. We present the rationale underlying the expected relative error computation based on simple binomial distributions. A series of simulated in machina experiments were performed to test the validity of the a priori computation of expected errors, thus confirming the predictions. The step-by-step procedure of the relative error estimation is given. We also discuss the constraints under which an LDA must be performed.

HIV rapid testing as a key strategy for prevention of mother-to-child transmission in Brazil

OBJECTIVE: To assess the feasibility of HIV rapid testing for pregnant women at maternity hospital admission and of subsequent interventions to reduce perinatal HIV transmission. METHODS: Study based on a convenience sample of women unaware of their HIV serostatus when they were admitted to delivery in public maternity hospitals in Rio de Janeiro and Porto Alegre, Brazil, between March 2000 and April 2002. Women were counseled and tested using the Determine HIV1/2 Rapid Test. HIV infection was confirmed using the Brazilian algorithm for HIV infection diagnosis. In utero transmission of HIV was determined using HIV-DNA-PCR. There were performed descriptive analyses of sociodemographic data, number of previous pregnancies and abortions, number of prenatal care visits, timing of HIV testing, HIV rapid test result, neonatal and mother-to-child transmission interventions, by city studied. RESULTS: HIV prevalence in women was 6.5% (N=1,439) in Porto Alegre and 1.3% (N=3.778) in Rio de Janeiro. In Porto Alegre most of women were tested during labor (88.7%), while in Rio de Janeiro most were tested in the postpartum (67.5%). One hundred and forty-four infants were born to 143 HIV-infected women. All newborns but one in each city received at least prophylaxis with oral zidovudine. It was possible to completely avoid newborn exposure to breast milk in 96.8% and 51.1% of the cases in Porto Alegre and Rio de Janeiro, respectively. Injectable intravenous zidovudine was administered during labor to 68.8% and 27.7% newborns in Porto Alegre and Rio de Janeiro, respectively. Among those from whom blood samples were collected within 48 hours of birth, in utero transmission of HIV was confirmed in 4 cases in Rio de Janeiro (4/47) and 6 cases in Porto Alegre (6/79). CONCLUSIONS: The strategy proved feasible in maternity hospitals in Rio de Janeiro and Porto Alegre. Efforts must be taken to maximize HIV testing during labor. There is a need of strong social support to provide this population access to health care services after hospital discharge.