Enzymatic activity and mineralization of carbon and nitrogen in soil cultivated with coffee and green manures

There are great concerns about degradation of agricultural soils. It has been suggested that cultivating different plant species intercropped with coffee plants can increase microbial diversity and enhance soil sustainability. The objective of this study was to evaluate enzyme activity (urease, arylsulfatase and phosphatase) and alterations in C and N mineralization rates as related to different legume cover crops planted between rows of coffee plants. Soil samples were collected in a field experiment conducted for 10 years in a sandy soil in the North of Paraná State, Brazil. Samples were collected from the 0-10 cm layer, both from under the tree canopy and in-between rows in the following treatments: control, Leucaena leucocephala, Crotalaria spectabilis, Crotalaria breviflora, Mucuna pruriens, Mucuna deeringiana, Arachis hypogaea and Vigna unguiculata. The soil was sampled in four stages of legume cover crops: pre-planting (September), after planting (November), flowering stage (February) and after plant residue incorporation (April), from 1997 to 1999. The green manure species influenced soil enzyme activity (urease, arylsulfatase and phosphatase) and C and N mineralization rates, both under the tree canopy and in-between rows. Cultivation of Leucaena leucocephala increased acid phosphatase and arilsulfatase activity and C and N mineralization both under the tree canopy and in-between rows. Intercropped L. leucocephala increased urease activity under the tree canopy while C. breviflora increased urease activity in-between rows.

Ammonia volatilization in no-till system in the south-central region of the State of Paraná, Brazil

Ammonia (NH3) volatilization can reduce the efficiency of urea applied to the surface of no-till (NT) soils. Thus, the objectives of this study were to evaluate the magnitude of NH3 losses from surface-applied urea and to determine if this loss justifies the urea incorporation in soil or its substitution for other N sources under the subtropical climatic conditions of South-Central region of Paraná State, Brazil. The experiment, performed over four harvesting seasons in a clayey Hapludox followed a randomized block design with four replicates. A single dose of N (150 kg ha-1) to V5 growth stage of corn cultivated under NT system was applied and seven treatments were evaluated, including surface-applied urea, ammonium sulfate, ammonium nitrate, urea with urease inhibitor, controlled-release N source, a liquid N source, incorporated urea, and a control treatment with no N application. Ammonia volatilization was evaluated for 20 days after N application using a semi-open static system. The average cumulative NH3 loss due to the superficial application of urea was low (12.5 % of the applied N) compared to the losses observed in warmer regions of Southeastern Brazil (greater than 50 %). The greatest NH3 losses were observed in dry years (up to 25.4 % of the applied N), and losses decreased exponentially as the amount of rainfall after N application increased. Incorporated urea and alternative N sources, with the exception of controlled-release N source, decreased NH3 volatilization in comparison with surface-applied urea. Urea incorporation is advantageous for the reduction of NH3 volatilization; however, other aspects as its low operating efficiency should be considered before this practice is adopted. In the South-Central region of Paraná, the low NH3 losses from the surface-applied urea in NT system due to wet springs and mild temperatures do not justify its replacement for other N sources.

Assessment of micronutrient extractants from soils of Paraná, Brazil

In Brazil, plant-available micronutrients in the soil can be determined by several chemical extractants, the most common of which are dilute acid and chelating solutions. The purpose of this study was to assess the extractants 0.1 mol L-1 HCl, Mehlich-1, Mehlich-3 and DTPA for analysis of the micronutrients Cu, Zn, Fe, and Mn in soils from the state of Paraná. In samples from 12 soils (0-20 cm layer), wheat was planted (Triticum aestivum), grown for 42 days after emergence, and then bean (Phaseolus vulgaris) for 38 days. At the end of each planting period, the soil was sampled again. All extractants tested to assess the availability of Cu, Zn, Fe, and Mn correlated with each other. The efficiency of the extractants HCl, Mehlich-3 and DTPA in assessing plant-available Cu was similar, unlike Mehlich-1, which proved less efficient. The extractants HCl, Mehlich-1 and Mehlich-3 were less efficient in estimating plant-available Zn and Fe, and the most indicated extractant is DTPA. The efficiency of the extractants HCl, Mehlich-1, Mehlich-3 and DTPA in assessing plant-available Mn in soils from Paraná was similar.

Mineralization of organic phosphorus in soil size fractions under different vegetation covers in the north of Rio de Janeiro

In unfertilized, highly weathered tropical soils, phosphorus (P) availability to plants is dependent on the mineralization of organic P (Po) compounds. The objective of this study was to estimate the mineralization of total and labile Po in soil size fractions of > 2.0, 2.0-0.25 and < 0.25 mm under leguminous forest tree species, pasture and "capoeira" (secondary forest) in the 0-10 cm layer of a Red-Yellow Latosol after 90 d of incubation. The type of vegetation cover, soil incubation time and soil size fractions had a significant effect on total P and labile P (Pi and Po) fraction contents. The total average Po content decreased in soil macroaggregates by 25 and 15 % in the > 2.0 and 2.0-0.25 mm fractions, respectively. In contrast, there was an average increase of 90 % of total Po in microaggregates of < 0.25 mm. Labile Po was significantly reduced by incubation in the > 2.0 (-50 %) and < 0.25 mm (-76 %) fractions, but labile Po increased by 35 % in the 2.0-0.25 mm fraction. The Po fraction relative to total extracted P and total labile P within the soil size fractions varied with the vegetation cover and incubation time. Therefore, the distribution of P fractions (Pi and Po) in the soil size fraction revealed the distinctive ability of the cover species to recycle soil P. Consequently, the potential of Po mineralization varied with the size fraction and vegetation cover. Because Po accounted for most of the total labile P, the P availability to plants was closely related to the mineralization of this P fraction.

The earthworm fauna of regenerating forests and anthropogenic habitats in the coastal region of Paraná

The aim of this study was to evaluate abundance, biomass and diversity of earthworms in the southern coast region of the Mata Atlântica biodiversity hotspot. A total of 51 study sites in pastures, banana monocultures, mixed agroforestry systems, secondary forests in succession and old-growth forests near the coast of Paraná, Brazil, were evaluated. Each site was sampled once. Species richness of the earthworms was generally low and varied little between sites. At all sites except for one, the peregrine species Pontoscolex corethrurus (Glossoscolecidae) strongly dominated. Three other peregrine species, Amynthas corticis, Amynthas gracilis (Megascolecidae) and Ocnerodrilus occidentalis (Ocnerodrilidae), were frequent in moist sites. No autochthonous species were found. Abundance and biomass of earthworms varied strongly within and between sites (0-338 individuals m-2, 0-96 g m-2 fresh weight). Pastures had significantly lower abundance than all other sites. The forest sites had similar earthworm abundance and biomass, with a tendency to be higher in younger succession stages. The coastal plain region has been strongly altered by human activities. Reasons for the lack of any autochthonous species and the dominance of one peregrine species require further investigation.

Stability of Citrus tristeza virus protective isolates in field conditions

The objective of this work was to monitor the maintenance of Citrus tristeza virus (CTV) protective isolates stability in selected clones of 'Pêra' sweet orange (Citrus sinensis), preimmunized or naturally infected by the virus, after successive clonal propagations. The work was carried out in field conditions in the north of Paraná State, Brazil. Coat protein gene (CPG) analysis of 33 isolates collected from 16 clones of 'Pêra' sweet orange was performed using single strand conformational polymorphism (SSCP). Initially, the isolates were characterized by symptoms of stem pitting observed in clones. Then viral genome was extracted and used as template for the amplification of CPG by reverse transcription polimerase chain reaction (RTPCR). RTPCR products electrophoretic profiles were analyzed using the Jaccard coefficient and the UPGMA method. The majority of the clones had weak to moderate stem pitting symptoms and its CTV isolates showed alterations in the SSCP profiles. However, the stability of the protective complex has been maintained, except for isolates from two analised clones. Low genetic variability was observed within the isolates during the studied years.

Adaptation of anthurium cultivars as cut flowers in a subtropical area

The objective of this work was to evaluate the adaptation of anthurium (Anthurium andraeanum) cultivars as cut flowers in a subtropical area, located in north of Paraná State, Brazil. The Apalai, Ianomami, Kinã, nK 102, Parakanã, Rubi, and Terena cultivars were cultivated in a nursery under 80% shade. The number of leaves and inflorescences, floral stem length, length and width of inflorescences, and spadix length were evaluated. The experimental design was in completely randomized blocks, with six replicates and five plants per plot. During the 18 months evaluated, 'Parakanã' produced 11 inflorescences per plant, whereas the other cultivars produced seven to nine inflorescences per plant. The number of leaves produced per plant was: 'Ianomami', 25; 'Parakanã', 20; 'Apalai' and 'Terena', 15; 'Kinã' and 'Rubi', 11; and 'nK 102', 9. The Apalai, nK 102, Parakanã, and Rubi cultivars are the most recommended as cut flowers; the Ianomami cultivar is not recommended as a cut flower in this region.

Variation of essential oil composition of Tapirira guianensis Aubl. (Anacardiaceae) from two sandbank forests, north of Brazil

Tapirira guianensis (Anacardiaceae) is used in traditional medicine and is important for the recovery of degraded areas and riparian forests because the T. guianensis fruits are highly consumed by wildlife. Volatile components from dried leaves and branches of five individual plants of T. guianensis were collected in two sandbank forests of the State of Pará (Extractive Reserve Maracanã and Area of Environmental Protection Algodoal/Maiandeua), extracted by hydrodistillation using a Clevenger-type apparatus, and analyzed by GC/MS. The ten oils obtained are comprised mostly of sesquiterpene hydrocarbons (58.49 to 100%), with (E)-caryophyllene, β-selinene, α-selinene, β-sesquiphellandrene, and α-zingiberene being the most prominent. The results of the oil compositions were processed by Hierarchical Component Analysis (HCA) allowing the establishment of three groups of essential oils for T. guianensis differentiated by the content of β-selinene/α-selinene (Type I), (E)-caryophyllene (Type II), and β-sesquiphellandrene/α-zingiberene (Type III).

Thermoanalytical study and characterization of native starches of Paraná pine seeds (Araucaria angustiofolia, Bert O. Ktze) and European chestnut seeds (Castanea sativa, Mill)

Starch is the most important carbohydrate storage in plants. It is a raw material with diverse botanical origins, and is used by the food, paper, chemical, pharmaceutical, textile and other industries. In this work, native starches of Paraná pine seeds (pinhão) (Araucária angustiofolia, Bert O. Ktze) and european chestnut seeds (Castanea sativa, Mill) were studied by thermoanalytical techniques: thermo-gravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC), as well as X-ray powder patterns diffractometry. Apparent and total amylose content was also determined.

Landscape structure in the northern coast of Paraná state, a hotspot for the brazilian Atlantic Forest conservation

The "Serra do Mar" region comprises the largest remnant of the Brazilian Atlantic Forest. The coast of the Paraná State is part of the core area of the "Serra do Mar" corridor and where actions for biodiversity conservation must be planned. In this study we aimed at characterizing the landscape structure in the APA-Guaraqueçaba, the largest protected area in this region, in order to assist environmental policies of this region. Based on a supervised classification of a mosaic of LANDSAT-5-TM satellite images (from March 2009), we developed a map (1:75,000 scale) with seven classes of land use and land cover and analyzed the relative quantities of forests and modified areas in slopes and lowlands. The APA-Guaraqueçaba is comprised mainly by the Dense Ombrophilous Forest (68.6% of total area) and secondary forests (9.1%), indicating a forested landscape matrix; anthropogenic and bare soil areas (0.8%) and the Pasture/Grasslands class (4.2%) were less representative. Slopes were less fragmented and more preserved (96.3% of Dense Ombrophilous Forest and secondary forest) than lowlands (71.3%), suggesting that restoration initiatives in the lowlands must be stimulated in this region. We concluded that most of the region sustains well-conserved ecosystems, highlighting the importance of Paraná northern coast for the biodiversity maintenance of the Atlantic Forest.

Mapping of summer crops in the State of Paraná, Brazil, through the 10-day spot vegetation NDVI composites

The search for low subjectivity area estimates has increased the use of remote sensing for agricultural monitoring and crop yield prediction, leading to more flexibility in data acquisition and lower costs comparing to traditional methods such as census and surveys. Low spatial resolution satellite images with higher frequency in image acquisition have shown to be adequate for cropland mapping and monitoring in large areas. The main goal of this study was to map the Summer crops in the State of Paraná, Brazil, using 10-day composition of NDVI SPOT Vegetation data for 2005/2006, 2006/2007 and 2007/2008 cropping seasons. For this, a supervised digital classification method with Parallelepiped algorithm in multitemporal RGB image composites was used, in order to generate masks of Summer cultures for each 10-day composition. Accuracy assessment was performed using Kappa index, overall accuracy and Willmott's concordance index, resulting in good levels of accuracy. This methodology allowed the accomplishment, with free and low resolution data, of the mapping of Summer cultures at State level.

Spatial autocorrelation of ndvi and gvi indices derived from landsat/tm images for soybean crops in the western of the state of Paraná in 2004/2005 crop season

This research aims at studying spatial autocorrelation of Landsat/TM based on normalized difference vegetation index (NDVI) and green vegetation index (GVI) of soybean of the western region of the State of Paraná. The images were collected during the 2004/2005 crop season. The data were grouped into five vegetation index classes of equal amplitude, to create a temporal map of soybean within the crop cycle. Moran I and Local Indicators of Spatial Autocorrelation (LISA) indices were applied to study the spatial correlation at the global and local levels, respectively. According to these indices, it was possible to understand the municipality-based profiles of tillage as well as to identify different sowing periods, providing important information to producers who use soybean yield data in their planning.

Rational use of water in a poultry slaughterhouse in the state of Paraná, Brazil: a case study

Agroindustries are major consumers of water. However, to adapt to environmental trends and be competitive in the market, they have sought rational use of water through water management in their activities. Cleaner Production can result in economic, environmental and social benefits, and in actions that promote reduction in water consumption. This case study was conducted in a slaughterhouse and poultry cold storage processing plant and aimed to identify points of excessive water consumption, and to propose alternatives for managing water resources by reducing consumption. Consumption data are presented in relation to the processing stages with alternatives proposed for the rational use of water, such as closure of mains water during shift changes. Following the implementation of recommendations, a reduction in water consumption of approximately 11,137 m³ per month was obtained, which equates to a savings of US$ 99,672 per year. From this study, it was concluded that the company under review could develop various improvement actions and make an important contribution to the preservation of water resources in the region where it operates.

Screening of antigenemia and isolation of Cryptococcus neoformans and C. gattii from cloaca and crop of birds in the state of Paraná, Brazil

Cryptococcus neoformans and C. gattii are associated with dry bird excreta but rarely recovered from birds' digestive tract. The objective of the present study was (1) to verify the existence of C. neoformans and C. gattii in crop and cloaca of wildlife and captivity birds hypothesizing about a possible primary source of this yeast in the excreta, and (2) to determine the fungi's invasive capability in avian species through latex agglutination. For that purpose, 172 cloacal and 77 crop samples of domestic pigeon, Passerine, and Psittacine birds were collected. None of these samples was positive, suggesting that the yeast is not saprobiotic in the digestive tract of these birds. Only one out of 82 serum samples collected from pigeons and Psittacine birds was positive (title 1:2) showing that Cryptococcus sp. probably has a low invasive capability in birds, and is thus considered only a dry excreta colonizer.

A seroepidemiological survey of Mycobacterium avium subsp. paratuberculosis in sheep from North of Portugal

The aim of this study was evaluate the risk factors for Mycobacterium avium subsp. paratuberculosis (Map) seroprevalence in sheep in the North of Portugal. The effects on seroprevalence of several variables such as individual characteristics, management practices, farm characteristics, animal health, and available veterinary services were evaluated. This information was then used in a multivariable logistic regression model in order to identify risk factors for Map seropositivity. Univariable analysis was used to screen the variables used in the logistic regression model. Variables that showed p values of <0.15 were retained for the multivariable analysis. Fifteen variables were associated with paratuberculosis in univariable analysis. The multivariable logistic regression model identified a number of variables as risk factors for seropositivity like sheep pure local and/or a cross of a local breed (OR=2.02), herd size with 31-60 head (OR=2.14), culling during the Spring-Summer season (OR=1.69) and the use of an anti-parasitic treatment such as Ivermectin as the only anti-parasitic medication (OR=5.60). Potential risk factors identified in this study support current recommendations for the control of paratuberculosis.