bluuebunny/crossref_metadata_2025 huggingface dataset:
Cation exchange capacity of an oxisol amended with an effluent from domestic sewage treatment
Authors: Fonseca Adriel Ferreira da , Alleoni Luís Reynaldo Ferracciú , Melfi Adolpho José , Montes Célia Regina
Published: September 2007

The addition of Na-rich anthropogenic residues to tropical soils has stimulated the scientific community to study the role of sodium in both the soil solution and the exchange complex. In this study, several different methods were used to calculate the concentration of exchangeable and soluble cations and this data was then used to establish correlations between the level of these cations and both the accumulation of various elements and the dry weight of maize grown in a greenhouse under different conditions. In the closed environments of the pots, the most suitable method for calculating the effective cation exchange capacity (ECEC) was the cation exchange capacity calculated by cations removed with barium chloride solution (CEC S). Then again, the actual cation exchange capacity (CEC A) should be measured by using Mg adsorption to prevent ionic force from influencing electric charges. A strong positive correlation was obtained between the concentrations of Na in the 1:2 soil:water extracts and the accumulation of Na in the maize plants, indicating saline or double acid extractors are not needed when monitoring the Na concentration only.
Chemical attributes of a degraded soil after application of water treatment sludges
Authors: Silva Érica Tomé da , Melo Wanderley José de , Teixeira Sandra Tereza
Published: September 2007

Mining is an activity that tends to degrade the environment. The restoration of mining areas, aims to accelerate and improve the succession process according to its future use. The objective of this work was to rehabilitate a soil degraded by tin mining activities in the Amazon Basin (Jamari National Forest, State of Rondônia) with the application of water treatment sludge (WTS), and verify the effect of sludge on values of pH (CaCl2 0.01 mol L-1), organic matter, P, Ca, Mg, K, H+Al, and soil micronutrient contents when cultivated with native plants, legumes, and grass species. A factorial (3 X 5) experimental design was used to optimize the rehabilitation of these areas including three N rates (100, 200, and 300 mg N kg-1 soil supplied by WTS), five plant species (grasses, legumes, and native plants), and two controls (degraded soil with no fertilizer and degraded soil fertilized with mineral fertilizers), with four replications. WTS increased pH values. The chemical products used to treat the water contributed, in greater extension, to increase soil Ca and Fe contents. The use of WTS as fertilizer proved viable, since it contains nutrients for plants; however, nitrogen should not be used as a criterion to define the rate of sludge application, because it is present at small amounts in the WTS.
Routine soil testing to monitor heavy metals and boron
Authors: Abreu Cleide Aparecida de , van Raij Bernardo , Abreu Mônica Ferreira de , González Antonio Paz
Published: September 2007

Microelements are an important issue in agriculture, due to their need as micronutrients for plants and also to the possibility of the build-up of toxic levels for plants and animals. Five micronutrients (B, Cu, Fe, Mn, and Zn) are routinely determined in soil analysis for advisory purposes. Other four elements (Cd, Cr, Pb, and Ni) are considered environmentally important heavy metals in farmland soils. Thus high contents of these metals in cropland might go eventually unnoticed. In this paper we present an approach that can be used to monitor the contents of the nine elements in farmland soils using advisory soil testing. A total of 13,416 soil samples from 21 Brazilian states, 58% of them from the state of São Paulo, sent by farmers were analyzed. Boron was determined by hot water extraction and the other metals were determined by DTPA (pH 7.3) extraction. The ranges of content, given in mg dm-3 soil, were the following: B, 0.01-10.6; Cu, 0.1-56.2; Fe, 0.5-476; Mn, 1-325; Zn, 1-453; Cd, 0.00-3.43, Cr, 0.00-42.9; Ni, 0.00-65.1; Pb, 0.00-63.9. The respective average values for São Paulo were: B-0.32; Cu-2.5; Fe-36; Mn-16; Zn-4.8; Cd-0.02; Cr-0.03; Ni-0.18; Pb-0.85. For other states the results are in the same ranges. The higher values are indicative of anthropogenic inputs, either due to excess application of fertilizers or to industrial or mining activities. The conclusion is that massive chemical analysis of farmland soil samples could serve as a database for indicating potential micronutrient deficiency and excesses or heavy metal buil-up in croplands, allowing preventive actions to be taken.
Soil tillage, water erosion, and calcium, magnesium and organic carbon losses
Authors: Bertol Ildegardis , Guadagnin Jean Cláudio , González Antonio Paz , Amaral André Júlio do , Brignoni Leonardo Felipe
Published: September 2007

Soil tillage influences water erosion, and consequently, losses of calcium, magnesium and organic carbon in surface runoff. Nutrients and organic carbon are transported by surface runoff in particulate form, adsorbed to soil colloids or soluble in water, depending on the soil tillage system. This study was carried out on an Inceptisol, representative of the Santa Catarina highlands, southern Brazil, between November 1999 and October 2001, under natural rainfall. The soil tillage treatments (no replications) were: no-tillage (NT), minimum soil tillage with chiseling + disking (MT), and conventional soil tillage with plowing + two diskings (CT). The crop cycles sequence was soybean (Glycine max), oats (Avena sativa), beans (Phaseolus vulgaris) and vetch (Vicia sativa). Conventional soil tillage treatment with plowing + two disking in the absence of crops (BS) was also studied. Calcium and magnesium concentrations were determined in both water and sediments of the surface runoff, while organic carbon was measured only in sediments. Calcium and magnesium concentrations were greater in sediments than in surface runoff, while total losses of these elements were greater in surface runoff than in sediments. The greatest calcium and magnesium concentrations in surface runoff were obtained under CT, while in sediments the greatest concentration occurred under MT. Organic carbon concentration in sediments did not differ under the different soil tillage systems, and the greatest total loss was under CT system.
Estimating the total leaf area of the green dwarf coconut tree (Cocos nucifera L.)
Authors: Sousa Elias Fernandes de , Araújo Marilaine Campanati , Posse Robson Prucoli , Detmann Edenio , Bernardo Salassier , Berbert Pedro Amorim , Santos Paulo Albernaz dos
Published: September 2007

Leaf area has significant effect on tree transpiration, and its measurement is important to many study areas. This work aimed at developing a non-destructive, practical, and empirical method to estimate the total leaf area of green dwarf coconut palms (Cocos nucifera L.) in plantations located at the northern region of Rio de Janeiro state, Brazil. A mathematical model was developed to estimate total leaf area values (TLA) as function of the average lengths of the last three leaf raquis (LR3), and of the number of leaves in the canopy (NL). The model has satisfactory degree of accuracy for agricultural engineering purposes.
Molecular confirmation of Maize rayado fino virus as the Brazilian corn streak virus
Authors: Hammond Rosemarie Wahnbaeck , Bedendo Ivan Paulo
Published: September 2007

Maize rayado fino virus (MRFV), present in various countries in Latin America, has shown similarities to corn streak virus that occurs in Brazil, regarding pathogenic, serological and histological characteristics. In the current report both virus were molecularly compared to confirm the similarities between them. MRFV was identified by nucleic acid hybridization in samples of maize tissues exhibiting symptoms of "corn stunt" disease, collected from two Brazilian States - São Paulo and Minas Gerais. The coat protein gene and 3'non-translated region of MRFV were amplified from infected tissues by reverse transcription-polymerase chain reaction (RT-PCR) using MRFV-specific primers, and were characterized by nucleotide sequence and phylogenetic analysis of the cloned PCR products. Phylogenetic analysis of the relationships between the Brazilian isolates and isolates obtained from Latin America and the United States reveals a close relationship to isolates from Brazil, Peru and Bolivia. Results support the proposal that the Brazilian corn streak virus be regarded as an isolate of MRFV and provide evidence for the presence of MRFV in "corn stunt' disease in Brazil.
Learning soil classification with the Kayapó indians
Authors: Cooper Miguel , Teramoto Edson Roberto , Vidal-Torrado Pablo , Sparovek Gerd
Published: September 2007

The Kayapó Xicrin do Cateté (Xicrin) indigenous reserve is located within the Amazon forest in Pará (Brazil). The Xicrins have developed a soil classification system that is incorporated in their language and culture. The etymology of their classification system and its logical structure makes it similar and comparable with modern soil classification. The etymology of the Xicrin's language is based on the junction of radicals to form words for different soil names. The name of the soil is formed by the main noun radical "puka", to which adjectives referring to soil morphological attributes are added. Modern classification systems are also based on similar morphological variables, and analytical support for defining boundaries of chemical or physical soil attributes are important only in lower hierarchical levels. Soil scientists have developed a soil classification system that is sensitive for the restrictions and potentialities the soil will show for modern agriculture. The Xicrins classify soils for what is important for their life style, i.e. a harmonic and friendly life with the resources they gain from the forest.
Spatial distribution of Pseudaletia sequax Franclemlont in triticale under no-till management
Authors: Grego Célia Regina , Vieira Sidney Rosa , Lourenção André Luiz
Published: September 2007

The knowledge of the spatial distribution of insect populations in crops allows the estimation of the population density in space, the classification of damage impact on yield as well as decisions to be made about control measures. To evaluate the spatial distribution of the wheat armyworm Pseudaletia sequax Franclemont, in relation to the development and yield of triticale (Triticum secale Wittmack) under no-till management, samplings were taken at 302 points in a square grid measuring 10 x 10 m, in Campinas, SP, Brazil. The caterpillar population was evaluated by counting their number per meter at the base of triticale plants. Grain yield (kg ha-1), cover of the above-ground part (kg ha-1), mean plant height (m), and ground cover percentage were evaluated after the triticale crop was mechanically harvested, with the measurement of the mass of straw left on soil surface. Geostatistics was used to analyze spatial variability, by means of semivariogram analysis, and interpolation of data by both ordinary and indicator kriging, considering the injury threshold level of ten caterpillars per square meter to construct isoline maps. Spatial dependence occurred for all variables, demonstrating an aggregate spatial distribution pattern of the caterpillar in triticale. Random sampling in this area would fail to reveal that grain yield was affected at the location with the greatest occurrence of the caterpillar. At that location, the economic injury level was exceeded, which would justify the adoption of control measures against the pest.
Geostatistical analysis for soil moisture content under the no tillage cropping system
Authors: Grego Célia Regina , Vieira Sidney Rosa , Antonio Aline Maria , Della Rosa Simone Cristina
Published: September 2007

Experiments in agriculture usually consider the topsoil properties to be uniform in space and, for this reason, often make inadequate use of the results. The objective of this study was to assess the variability for soil moisture content using geostatistical techniques. The experiment was carried out on a Rhodic Ferralsol (typic Haplorthox) in Campinas, SP, Brazil, in an area of 3.42 ha cultivated under the no tillage system, and the sampling was made in a grid of 102 points spaced 10 m x 20 m. Access tubes were inserted down to one meter at each evaluation point in order to measure soil moisture contents (cm³ cm-3) at depths of 30, 60 and 90 cm with a neutron moisture gauge. Samplings were made between the months of August and September of 2003 and in January 2004. The soil moisture content for each sampling date was analyzed using classical statistics in order to appropriately describe the central tendency and dispersion on the data and then using geostatistics to describe the spatial variability. The comparison between the spatial variability for different samplings was made examining scaled semivariograms. Water content was mapped using interpolated values with punctual kriging. The semivariograms showed that, at the 60 cm depth, soil water content had moderate spatial dependence with ranges between 90 and 110 m. However, no spatial dependence was found for 30 and 90 cm depths in 2003. Sampling density was insufficient for an adequate characterization of the spatial variability of soil moisture contents at the 30 and 90 cm depths.
Soybean yield and quality a function oflime and gypsum applications
Authors: Caires Eduardo Fávero , Churka Susana , Garbuio Fernando José , Ferrari Roseli Aparecida , Morgano Marcelo Antonio
Published: September 2007

Effects of lime and gypsum applications on the quality of soybeans grown under no-till (NT) are not well defined yet. A field trial established in 1998 on a dystrophic clayey Rhodic Hapludox, at Ponta Grossa, State of Paraná, Brazil, evaluated grain yield and soybean quality based on oil, protein and nutrient content, after lime and gypsum applications under NT, in a randomized complete block design (n = 3), split-plot experiment. In the main plots, the treatments with dolomitic lime were: control (no lime), split application of lime on the surface (three yearly applications of 1.5 Mg ha¹), surface lime (4.5 Mg ha¹), and incorporated lime (4.5 Mg ha¹). Subplots received four different rates of gypsum: 0, 3, 6, and 9 Mg ha-1. The soybean crop was evaluated in the agricultural years of 20022003 and 20032004. After 58 months, the correction of acidity through surface liming, with full or split rates, was more pronounced in the top layer (00.05 m) and there was greater reaction at the depths of 0.050.10 and 0.100.20 m when lime was incorporated. Surface or incorporated liming had no effect on grain yield, soybean oil and protein content. Gypsum improved chemical subsoil conditions, raising pH (0.01 mol L-1 CaCl2) as well as Ca2+ and S-SO4(2-) contents; it also caused exchangeable Mg2+ leaching in the soil profile. The application of gypsum did not affect grain yield, yet it improved soybean quality through an increase in protein and S contents, in 20032004, and in grain P, K and Ca, in the two cropping years. The use of gypsum in NT soybeans can be especially important for fields of seeds production.
Spore density and root colonization by arbuscular mycorrhizal fungi in preserved or disturbed Araucaria angustifolia (Bert.) O. Ktze. ecosystems
Authors: Moreira Milene , Baretta Dilmar , Tsai Siu Mui , Cardoso Elke Jurandy Bran Nogueira
Published: September 2007

Araucaria angustifolia (Bert.) O. Ktze., a native forest tree from Brazil, is under extinction risk. This tree depends on arbuscular mycorrhizal fungi for growth and development, especially in tropical low-P soils but, despite being a conifer, Araucaria does not form ectomycorrhiza, but only the arbuscular endomycorrhiza. This study aimed at surveying data on the spore density and root colonization (CR) by arbuscular mycorrhizal fungi (AMF) in Araucaria angustifolia forest ecosystems, in order to discriminate natural, implemented, and anthropic action-impacted ecosystems, by means of Canonical Discriminant Analysis (CDA). Three ecosystems representative of the Campos do Jordão (SP, Brazil) region were selected: 1. a native forest (FN); 2. a replanted Araucaria forest (R); and 3. a replanted Araucaria forest, submitted to accidental fire (RF). Rhizosphere soil and roots were sampled in May and October, 2002, for root colonization, AMF identification, and spores counts. Root percent colonization rates at first collection date were relatively low and did not differ amongst ecosystems. At the second period, FN presented higher colonization than the other two areas, with much higher figures than during the first period, for all areas. Spore density was lower in FN than in the other areas. A total of 26 AMF species were identified. The percent root colonization and spore numbers were inversely related to each other in all ecosystems. CDA indicated that there is spatial distinction among the three ecosystems in regard to the evaluated parameters.
Neural network and state-space models for studying relationships among soil properties
Authors: Timm Luís Carlos , Gomes Daniel Takata , Barbosa Emanuel Pimentel , Reichardt Klaus , Souza Manoel Dornelas de , Dynia José Flávio
Published: September 2007

The study of soil property relationships is of great importance in agronomy aiming for a rational management of environmental resources and an improvement of agricultural productivity. Studies of this kind are traditionally performed using static regression models, which do not take into account the involved spatial structure. This work has the objective of evaluating the relation between a time-consuming and "expensive" variable (like soil total nitrogen) and other simple, easier to measure variables (as for instance, soil organic carbon, pH, etc.). Two important classes of models (linear state-space and neural networks) are used for prediction and compared with standard uni- and multivariate regression models, used as reference. For an oat crop cultivated area, situated in Jaguariuna, SP, Brazil (22º41' S, 47º00' W) soil samples of a Typic Haplustox were collected from the plow layer at points spaced 2 m apart along a 194 m spatial transect. Recurrent neural networks and standard state-space models had a better predictive performance of soil total nitrogen as compared to the standard regression models. Among the standard regression models the Vector Auto-Regression model had a better predictive performance for soil total nitrogen.
Unraveling the signaling and signal transduction mechanisms controlling arbuscular mycorrhiza development
Authors: Lambais Marcio Rodrigues
Published: September 2007

Arbuscular mycorrhiza (AM) are the most widespread symbiotic associations between plant roots and soil fungi. AM can contribute to increasing the survival and fitness of plants to limiting environments mostly due to their ability in improving nutrient uptake from the soil solution. Despite their ecological significance, the mechanisms controlling AM development and functioning are largely unknown. The obligate mutualistic nature of the arbuscular mycorrhizal fungi (AMF) has hampered the advances on the understanding and application of the symbiosis. Significant alterations in the genetic programs of both symbionts are required for the successful establishment of an AM, and complex signaling and signal transduction mechanisms are likely involved. The analyses of legume mutants affected in the development of nitrogen fixing nodules and AM suggest that part of the signal transduction pathways involved in the regulation of both symbioses are conserved. Even though the use of genomics of model plants has helped to advance our understanding of the regulatory mechanisms in AM, identifying the signal molecules involved in plant-AMF communication and determining their transduction pathways is still essential for its biotechnological application in agriculture.
Estimating forage intake of lactating dual-purpose cows using chromium oxide and n-alkanes as external markers
Authors: Oliveira Dimas Estrasulas de , Medeiros Sérgio Raposo de , Tedeschi Luis Orlindo , Aroeira Luís Januário Magalhães , Silva Sila Carneiro da
Published: September 2007

The n-alkanes have been used to estimate forage dry matter intake, digestibility and the diet composition in grazing animals. The objective this study was to compare chromium oxide and n-alkanes techniques used to estimate forage intake. Twenty lactating dual-purpose cows receiving two sources of fat (treatments: conjugated linoleic acid (CLA) or Megalac (control)) plus 4 kg of concentrate were dosed with n-alkanes and chromium oxide to estimate the intake of stargrass (Cynodon nlemfüensis Vanderyst var. nlemfüensis). The in vitro dry matter (DM) digestibility of the stargrass and concentrate were used to estimate the nutritive value of the digesta. The n-alkanes between C23 and C36 were quantified in the digesta and feces. The regression between metabolizable energy requirement (MEr, Mcal d-1) and supply derived from forage DM intake estimated using chromium oxide was ME IntakeCr = 19.1 + 0.62 MEr (R² = 0.27) and the same relationship estimated using C35:C36 n-alkane ratio was ME IntakeC35:C36 = 9.3 + 0.77 MEr (R² = 0.52). There was a treatment effect on fecal concentration of chromium oxide with daily and period variations. For the n-alkane technique, treatment and period effects and a linear effect of day of collection on the fecal concentrations of C35 were found. For C36 fecal concentrations, there was a treatment effect and a quadratic effect of collection day. There was no treatment effect on the fecal concentration of the C35:C36 ratio, but a period effect and a linear effect of day of collection were found. Estimates of daily intake using the two markers were different, but those obtained using the C35:C36 pair of n-alkanes were more precise than those obtained using chromium oxide and in vitro digestibility. Management of experimental animals could have influenced the concentration of markers in the feces, determining variations and inconsistencies that partially explain the inaccuracy of the estimates.
Electrical conductivity as an indicator of pea seed aging of stored at different temperatures
Authors: Panobianco Maristela , Vieira Roberval Daiton , Perecin Dilermando
Published: September 2007

Research on soybean seed has revealed that conductivity test results may be influenced by storage temperature and that an apparent direct relationship between deterioration at low temperatures and loss of cellular membrane integrity is not evident. The objective of this study was to verify the influence of low storage temperatures on electrical conductivity results in other species, such as seeds of two pea cultivars studied temperatures were: 10, 20, 25, 20/10 and 25/10ºC. The physiological potential of the seeds was evaluated every three months during an 18 month storage period using germination, accelerated aging and electrical conductivity tests. The electrical conductivity test was not a good indicator for the degree of seed deterioration stored at low temperatures. Seed deterioration at 10ºC did not seem to be directly related to the loss of membrane integrity, possibly due to membrane repair or reorganization during storage at this temperature.
Seasonal growth variation of peach palms cultivated in containers under subtropical conditions
Authors: Tucci Maria Luiza Sant'Anna , Bovi Marilene Leão Alves , Machado Eduardo Caruso , Spiering Sandra Heiden
Published: September 2007

Peach palm (Bactris gasipaes Kunth) is grown in the São Paulo State, Brazil, under climate seasonal variation conditions, mainly temperature and rainfal with possible effects on plant physiology. Recently, due to a higher interest in carrying out physiological experiments on the species, there has been a requirement for more controlled experimental conditions. Therefore, with the aim of studying the seasonal variation of peach palm growth for heart-of-palm production, as well as the possibility of growing them until harvest in pots, for future utilization in physiological experiments, this work was carried out in Campinas, SP, Brazil, with 40 spineless peach palms. One year after seed germination, seedlings were transplanted to 80 L plastic pots, spaced 2 x 1 m, arranged in four rows of ten plants. All plants had vegetative growth evaluated monthly by measurements of main stem height, number of functional leaves, number of offshoots and length of leaf raquis. Seasonal variations were observed in terms of height and diameter growth as well as raquis length of the youngest leaf and in the evolution of the number of leaves. After two years, plants had an average height of 230 cm, six functional leaves and 11.7 offshoots. Positive correlations (P < 0.001) were observed between growth variables and the average temperatures, rainfall as well as insolation of the 30, 60, 90 or 120 days previous to the measurements. Peach palms could be grown in containers until first harvest, without restrictions to growth.
Bacillus cereus in Brazilian Ultra High Temperature milk
Authors: Pacheco-Sanchez Cristiana de Paula , Massaguer Pilar Rodriguez de
Published: September 2007

Brazilian Ultra High Temperature (UHT) milk consumption has increased during the last decade from 187 to 4,200 million liters. In the continuous UHT process, milk is submitted for 2-4 s to 130-150ºC, in a continuous flow system with immediate refrigeration and aseptical packing in hermetic packages. This research had the purpose to verify the incidence of B. cereus species from the B. cereus group, in UHT milk. In 1998 high indexes of these organisms were reported, reaching 34.14% of the analyzed samples. Beyond this fact, there was the need to establish methods and processes adjusted for correct identification of B. cereus. Thus, commercial sterility tests of 6,500 UHT milk packages were investigated in two assays, after ten days incubation at 37ºC and 7ºC to germinate all possible spores and/or to recuperate injured vegetative cells followed by pH measurement. Samples (1,300 packages each) from five Brazilian UHT plants of whole UHT milk processed by direct steam injection, packaged in carton were investigated for the presence of Bacillus cereus through phenotypic and genetic (PCR) tests. Values of pH were different for the samples, ranging between 6.57 and 6.73. After storage of the samples, only four packages with pH measurement below the lower limit of 6.5 were found and analyzed for the presence of B. cereus. This organism was not detected in any of the samples indicating that the five Brazilian UHT milk processors control pathogenic microorganisms and it can be said that the consumption of UHT milk does not present safety problems to consumers. Fourier Transform Infrared Spectroscopy (FTIR) and PCR tests were efficient and must be adopted to confirm the biochemical series for B. cereus.
Genetic variability and vegetative compatibility of Erythricium salmonicolor isolates
Authors: Sebastianes Fernanda Luiza de Souza , Maki Cristina Sayuri , Andreote Fernando Dini , Araújo Welington Luiz , Pizzirani-Kleiner Aline Aparecida
Published: September 2007

The Pink Disease is caused by Erythricium salmonicolor, which attacks broad hosts, such as citrus, coffee, rubber, Eucalyptus spp. and Acacia spp., infecting mainly branches. This disease became a serious problem in Brazil, reducing the citrus production up to 10%. However the genetic diversity and compatibility of the fungus E. salmonicolor from Brazilian citrus plants is not yet evaluated. Therefore, the aims of this study were to evaluate: i) the genetic variability of E. salmonicolor in the São Paulo and Minas Gerais States by the RAPD technique, and ii) the vegetative compatibility between these isolates. After RAPD analysis, six distinct groups were observed without correlation between the isolation site or host species. In the vegetative compatibility test, the contact of fungal hyphae between all evaluated crosses was observed, of which 84% presented hyphal fusion. Although the compatibility between strains was observed, no correlation between RAPD haplotypes and hyphal anastomosis was verified. These results show the importance of future studies on the sexual cycle of E. salmonicolor, since hyphal fusion, which precedes the formation of heterokaryons (sexual and parasexual reproduction) that could be responsible for the genetic variability in this species.
Carbon and nitrogen stocks of an Arenosol under irrigated fruit orchards in semiarid Brazil
Authors: Bernardi Alberto Carlos de Campos , Machado Pedro Luiz Oliveira de Almeida , Madari Beata Emoke , Tavares Sílvio Roberto de Lucena , Campos David Vilas Boas de , Crisóstomo Lindbergue de Araújo
Published: September 2007

Soil organic matter accumulation provides benefits to soil productivity and reduces atmospheric carbon concentration. However, little is known about the accumulation of C and N by sandy soils under perennial irrigated crops in semiarid regions. The objective of this study was to evaluate the effect of irrigated fruit orchard cultivation on the stocks of soil organic carbon (SOC) and total nitrogen (N) of an Arenosol/Quartzpsament from Paraipaba-CE, Semiarid Brazil. Soil samples were taken from irrigated orchards of banana (Musa ssp.), cashew (Anacardium ocidentale), guava (Psidium guajava), bullock's heart (Annona reticulata), mango (Mangifera indica), and sapote (Manilkara zapota) in the wetted-bulb and non-irrigated area between the plant rows. Additional samples were collected from adjacent areas under secondary Caatinga forest, and under a 2-year-old deforested area. Sampling depths were: 0-0.1, 0.1-0.2, and 0.2-0.4 m. The highest contents of SOC and N were found in the surface layer. The soil bulk density did not change in depth. The stocks of SOC and total N under secondary forest at 0-0.40 m layer were 27.6 and 2.4 Mg ha-1, respectively. Caatinga Forest conversion into fruit orchard cultivation led to a decrease of 5 to 23% and 4 to 21% on SOC and N stocks, respectively. Compared to other soil uses, sapote and bullock's heart contributed for a lower decrease of SOC and N stocks after deforestation. Guava, bullock's heart, mango and sapote contributed for improving the SOC stratification index.
Suitability of peanut residue as a nitrogen source for a rye cover crop
Authors: Balkcom Kipling Shane , Wood Charles Wesley , Adams James Fredrick , Meso Bernard
Published: September 2007

Leguminous winter cover crops have been utilized in conservation systems to partially meet nitrogen (N) requirements of succeeding summer cash crops, but the potential of summer legumes to reduce N requirements of a winter annual grass, used as a cover crop, has not been extensively examined. This study assessed the N contribution of peanut (Arachis hypogaea L.) residues to a subsequent rye (Secale cereale L.) cover crop grown in a conservation system on a Dothan sandy loam (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) at Headland, AL USA during the 2003-2005 growing seasons. Treatments were arranged in a split plot design, with main plots of peanut residue retained or removed from the soil surface, and subplots as N application rates (0, 34, 67 and 101 kg ha-1) applied in the fall. Peanut residue had minimal to no effect on rye biomass yields, N content, carbon (C) /N ratio, or N, P, K, Ca and Zn uptake. Additional N increased rye biomass yield, and N, P, K, Ca, and Zn uptakes. Peanut residue does not contribute significant amounts of N to a rye cover crop grown as part of a conservation system, but retaining peanut residue on the soil surface could protect the soil from erosion early in the fall and winter before a rye cover crop grows sufficiently to protect the typically degraded southeastern USA soils.
Agricultural use of treated sewage effluents: agronomic and environmental implications and perspectives for Brazil
Authors: Fonseca Adriel Ferreira da , Herpin Uwe , Paula Alessandra Monteiro de , Victória Reynaldo Luiz , Melfi Adolpho José
Published: September 2007

In many studies worldwide the use of treated sewage effluents (TSE) as water and nutrient sources in agricultural irrigation have been introduced as a viable alternative for wastewater destination in the environment. Considering agronomic and environmental aspects the objectives of this review were: (i) to present an overview of TSE irrigation on different agro-systems (annual crops, orchards, forests and forages); and (ii) to show the principal changes on chemical, physical and microbiological soil characteristics after TSE application. Various studies have revealed that the nutrient supply only by TSE irrigation was not sufficient to meet plant nutrient requirements resulting in yield decreases. The problem could be solved by an adapted effluent/fertilizer management. Moreover, TSE could generally substitute efficiently freshwater for irrigation. Regarding soil quality conditions, TSE irrigation affected mainly: (i) total soil carbon and nitrogen, and mineral nitrogen in soil solution; (ii) microbial activity, composition of microbial communities and their function; (iii) exchangeable calcium and magnesium; (iv) salinity, sodicity, clay dispersion and hydraulic conductivity. Other soil parameters considered in this review (e.g. heavy metals) did not present significant changes over short and medium terms. Due to the often observed accumulation of sodium and nitrogen losses (leaching, volatilization and denitrification) after TSE irrigation, the monitoring of these components is of crucial importance for a sustainable use. Finally, further studies on the technical-economical-environmental viability of TSE irrigation are required to establish reliable recommendations for TSE use particularly in Brazilian agro-systems.
Performance of new Hevea clones from IAC 400 series
Authors: Gonçalves Paulo de Souza , Silva Marcelo de Almeida , Aguiar Adriano Tosoni da Eira , Martins Maria Alice , Scaloppi Junior Erivaldo José , Gouvêa Lígia Regina Lima
Published: September 2007

The Hevea breeding program of Instituto Agronômico de Campinas (IAC) has completed clonal evaluation on the following series: IAC 100, IAC 200 and IAC 300. The performance of 22 clones of Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg., evolved at IAC, over a period of eleven years was evaluated in the Western Central part of the São Paulo State, Brazil. Among these 22 new clones, six were intraspecific hybrid clones (IAC 400, IAC 404, IAC 405, IAC 406, IAC 410, IAC 412) and the remaining are primary those resulted from selected ortets within half-sib progenies. An old popular clone RRIM 600, of Malaysian origin, was used as the control. The trial was laid out in a randomized block design with three replications. Yield performance over a period of four years, mean girth at the 11th year, girth increment before tapping and on tapping, thermal property of natural rubber produced, bark thickness, number of latex vessel rows in seven year virgin bark, percentage incidence of tapping panel dryness, wind damage and diseases like leaf and panel anthracnose have been observed. Sixty one percent of the clones were superior in relation to the control for yield. The clone IAC 400 recorded the highest yield (97.40 g tree-1 tap-1) over four years of tapping, followed by IAC 411 (78.87 tree-1 tap-1), whereas the control clone RRIM 600 recorded 50.86 g tree-1 tap-1. All selected clones were vigorous in growth. Girth increment of these clones was average to above average. Except for IAC 423, other clones had thick virgin bark at opening ranging from 4.84 mm for IAC 401 to 6.38 mm for IAC 416. The natural rubbers from IAC clones have shown good thermal stability up to 300ºC and no differences in the thermal behavior among rubber from clones of the IAC series and the clone RRIM 600 were found in inert atmosphere.
Thermal treatment of aluminous phosphates of the crandallite group and its effect on phosphorus solubility
Authors: Francisco Eros Artur Bohac , Prochnow Luís Ignácio , Toledo Maria Cristina Motta de , Ferrari Viviane Carillo , Jesus Sérgio Luís de
Published: September 2007

Optimization in the use of phosphate rocks is important and the residues of fertilizer production in the form of crandallite may be suitable for agronomic use after calcination. With the objective of evaluating the effect of thermal treatment of the aluminous phosphates of the crandallite group as related to solubility, crystalline structure and morphology, samples from the mine residues of three Brazilian phosphate deposits (Tapira-MG, Catalão-GO, and Juquiá-SP) were collected, air-dried, and screened to 100 mesh. Sub samples were thermally treated at 300, 500, 700, and 900°C for 2 hours. Treated and untreated materials were analyzed by X-ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectrometry, and for the total and soluble P contents. The treatment of samples: (i) raised P solubility in neutral ammonium citrate solution, (ii) caused the disorganization of the crystalline structure of crandallite at 500°C and above, and (iii) altered their morphology (cracking and rounding). The increase in P solubility of samples after calcination indicates that the agronomic utilization of these marginal P sources may be of interest since plant growth may be favored due to higher P availability. New studies to evaluate these materials in order to determine their agronomic effectiveness must be carried out to establish adequate conditions that favor their use by plants.
DRIS norms for evaluating the nutritional state of apple tree
Authors: Nachtigall Gilmar Ribeiro , Dechen Antonio Roque
Published: September 2007

For Brazilian conditions there are still no studies on the use of the diagnosis and recommendation of the integrated system (DRIS) for nutritional diagnosis of the apple tree. The nutritional diagnosis of the apple tree is made using the criterion of sufficiency range. The aim of this report is to establish DRIS norms to interpret the results of apple tree leaf analysis in South Brazil. The study covered the apple producing areas of the states of Rio Grande do Sul and Santa Catarina, in 70 orchards selected for their high productivity and employment of excellent management techniques. The concentrations of nitrogen, phosphorus, potassium, calcium, magnesium, boron, copper, iron, manganese, and zinc were determined in leaf samples. DRIS indices were calculated using two criteria for the choice of the ratio order of nutrients (F value - ratio of the variance of the relationships among nutrients between the reference group and the low productivity group, and R value - correlation coefficients between the productivity values and the relationship between pairs of nutrients) and three forms to calculate the nutrient functions (methods of Beaufils, Jones and Elwali & Gascho). The two criteria for the choice of the ratio order of the nutrients selected different ratios. The concentrations of nutrients presented positive correlations (P < 0.01) with the respective indices DRIS, except for N. The defined DRIS norms are applicable for the nutritional diagnosis of apple trees.
Phosphorus availability changes the internal and external endomycorrhizal colonization and affects symbiotic effectivenes
Authors: Nogueira Marco Antonio , Cardoso Elke Jurandy Bran Nogueira
Published: September 2007

Despite the awareness that high phosphorus (P) availability decreases the mycorrhizal root colonization in higher plants, the effects on the external mycelium are contradicting. The aim of this work was to assess the external mycelium of the arbuscular mycorrhizal fungi (AMF) Glomus intraradices and Gigaspora rosea, associated to soybean under increasing P levels (0, 25, 50, 100 and 200 mg kg-1). The tested hypotheses were: a) the amount of external mycelium depends on the fungal species; b) the P levels affect diferentially each mycorrhizal species; c) the mycorrhizal effectiveness depends on the amount of external mycelium. Mycorrhizal stimulus on plant biomass occurred at P levels of 0, 25 and 200 mg kg-1. Mycorrhizal root colonization and total external mycelium (TEM) decreased with increasing P levels. At zero P level, G. rosea produced less TEM than G. intraradices, which may be related to the lower mycorrhizal effectiveness for G. rosea. Both AMF increased the active external mycelium along P levels, but this increase was not related with symbiotic effectiveness. TEM was found to be closely related to root colonization and mycorrhizal effectiveness. The root colonization and TEM are mutually afected by P availability. Althoug G. intraradices produced more TEM than G. rosea along the P levels, they seemed to affect similarly the TEM for both AMF. More AMF species should be assessed in order to attest whether P levels affect the external mycelium differentially among them.
Occurrence of diazotrophic bacteria in Araucaria angustifolia
Authors: Neroni Rafaela de Fátima , Cardoso Elke Jurandy Bran Nogueira
Published: September 2007

Araucaria angustifolia is an environmentally threatened tree and the whole biota of the Araucaria Forest should be investigated with the aim of its preservation. Diazotrophic bacteria are extremely important for the maintenance of ecosystems, but they have never been studied in Araucaria Forests. In this study, diazotrophic bacteria were isolated from Araucaria roots and soil, when grown in semi-specific, semi-solid media. The diazotrophic character of some recovered isolates could be confirmed using the acetylene reduction assay. According to their 16S rRNA sequences, most of these isolates belong to the genus Burkholderia.
Scarification with sulphuric acid of Schizolobium amazonicum Huber ex Ducke seeds - FABACEAE
Authors: Cruz Eniel David , Carvalho José Edmar Urano de , Queiroz Rafaela Josemara Barbosa
Published: September 2007

Seed coat impermeability to water occurs in many species, including Schizolobium amazonicum Huber ex Ducke. To promote germination in seeds with coat impermeability the use of sulphuric acid (H2SO4) is recommended. The objective of this study was to identify a better time for the scarification with sulphuric acid for S. amazonicum seeds. The effect of scarification with sulphuric acid for 20, 40 and 60 min on germination and speed germination was studied for seeds that were either sowed immediately after scarification or after a 24-hour period of immersion in water. Seeds were sown on a mix of sand and sawdust (1:1). The experimental design was completely randomized with four replications of 50 seeds. The statistical analysis of germination was carried out at six, nine, 12, 15, 18, 21 and 24 days after sowing, in a factorial scheme. For speed germination the means were compared by the Tukey test. There was an interaction between treatments to overcome dormancy and immersion time after scarification in most evaluations. Immersion in water accelerated the beginning of germination. All treatments to overcome dormancy promoted seed germination. However, scarification for 60 min, showed better germination, 92% when immediately sown and 86.5% when sown after 24 hours. Speed germination index was highest for scarified seeds for 60 min followed by immersion in water. Scarification for 60 min was the most efficient treatment to promote germination in S. amazonicum seeds.
Historical land-cover/use in different slope and riparian buffer zones in watersheds of the state of São Paulo, Brazil
Authors: Silva Alexandre Marco da , Nalon Marco Aurélio , Kronka Francisco José do Nascimento , Alvares Clayton Alcarde , Camargo Plinio Barbosa de , Martinelli Luiz Antonio
Published: September 2007

Information about the land cover of a region it is a key information for several purposes. This paper aimed to elaborate land-cover maps using digital satellite images obtained in 1997 from seven watersheds (Piracicaba, Moji-Guaçu, Alto Paranapanema, Turvo Aguapeí, Peixe, and São José dos Dourados) located in the State of São Paulo, southeastern Brazil. Additionaly, this study evaluated the relationship between land-cover and slopes of the terrain of the seven watersheds. A third objective was to estimate the percentage of riparian vegetation currently remaining along the streams in a 30-meter width buffer zone. Three research questions were posed: i) What is the dominant land-cover of these watersheds? ii) Is the riparian vegetation well preserved in the 30m width buffer zone? If not, iii) what is the dominant land-cover in these areas and what would be the cost of recovering such areas? Pasture was the predominant land-cover, occurring in approximately 50% of the entire study area, while sugar cane (Saccharum officinarum) (14%) constituted the second most frequent land-cover. Approximately 50% of the area of the seven basins is considered flat (40%) or smoothly rolling (10%). The terrain only becomes hillier in the Piracicaba and Alto Paranapanema basins, where a little less than 50% have slopes higher than 8%. The total riparian buffer strip zone occupied an area equivalent to approximately 6,200 km². From this total, only 25% is preserved. Pasture is the main land-cover of the riparian buffer strip zone.
Soil loss risk and habitat quality in streams of a meso-scale river basin
Authors: Silva Alexandre Marco da , Casatti Lilian , Alvares Clayton Alcarde , Leite Aline Maria , Martinelli Luiz Antonio , Durrant Steven F.
Published: September 2007

Soil loss expectation and possible relationships among soil erosion, riparian vegetation and water quality were studied in the São José dos Dourados River basin, State of São Paulo, Brazil. Through Geographic Information System (GIS) resources and technology, Soil Loss Expectation (SLE) data obtained using the Universal Soil Loss Equation (USLE) model were analyzed. For the whole catchment area and for the 30 m buffer strips of the streams of 22 randomly selected catchments, the predominant land use and habitat quality were studied. Owing mainly to the high soil erodibility, the river basin is highly susceptible to erosive processes. Habitat quality analyses revealed that the superficial water from the catchments is not chemically impacted but suffers physical damage. A high chemical purity is observed since there are no urban areas along the catchments. The water is physically poor because of high rates of sediment delivery and the almost nonexistence of riparian vegetation.
Biodiversity and distribution of arbuscular mycorrhizal fungi in Araucaria angustifolia forest
Authors: Moreira Milene , Baretta Dilmar , Tsai Siu Mui , Gomes-da-Costa Sandra Maria , Cardoso Elke Jurandy Bran Nogueira
Published: September 2007

Araucaria angustifolia (Bert.) O. Ktze. is an endangered Brazilian coniferous tree that has been almost exterminated in the native areas because of uncontrolled wood exploitation. This tree has been shown to be highly dependent on arbuscular mycorrhizal fungi (AMF) and, therefore, AMF may be essential for forest sustainability and biological diversity. Root colonization, density and diversity of AMF spores were assessed in two Araucaria forest stands at the State Park of Alto Ribeira (PETAR), at two sampling dates: May and October. A comparison was made between a mature native stand composed of Araucaria trees mixed into a variety of tropical trees and shrubs, without any sign of anthropogenic interference (FN) and an Araucaria stand planted in 1987 (R), which has been used as a pasture. Assessments included percent root colonization, AMF spore numbers and species richness, Simpson's dominance index (Is), and Shannon's diversity index (H). Mycorrhizal root colonization did not differ between ecosystems in May. In October, however, the native stand (FN) presented a higher colonization than the planted forest (R), and the root colonization was more intense than in May. When considering both sampling periods and forests, 27 species of AM fungi, with higher numbers of spores in FN than in R were found. Canonical discriminant analysis (CDA) indicated Shannon's diversity index as the ecological attribute that contributed the most to distinguish between forest ecosystems, with higher value of H in FN in relation to R. CDA showed to be a useful tool for the study of ecological attributes.