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Silicon (Si) is a chemical element that is not yet considered essential for plants. However, over the past few decades, an increasing number of scientifi c studies have focused on the role of Si in soil-plant interactions. At the same time, many countries are leading the development and use of silicon-based fertilizers. Si can be taken up by plants predominantly in a mobile form (H4SiO4) in the soil through both passive and active uptake mechanisms. Therefore, Scopus data from 2012 to 2022 were used to understand the implementation and current status of research on the benefi cial effects of silicon fertilizers on soil and plants and the role of soil forms of silicon in improving soil quality. A bibliometric study of articles published in the database on the role of Si in soil and silicon fertilizers was carried out. Various tools, such as Microsoft Offi ce Excel 2021, VOS Viewer and Mapchart.net were used in this study. The fi nal literature includes 440 articles, 82% of which are scientifi c. Over the past decade, the number of published articles has increased signifi cantly. For example, in the years 2021–2022, a total of 91 articles were published, which is six times higher than the number of articles published in 2012–2013 (15 articles). This signifi cant increase in publications highlights the growing interest in the role Si and Si fertilizer research. It was found around 32.04% of China, 13.2% of the USA and 9.8% of Brazil the reviewed publications focused on the role of Si and Si fertilizers studies. Among the authors who published the most articles on this topic during the selected period are Wang X. (with 12 articles), Liang Yu., Rizwan M. and Ali S. (each with 8 articles). [ABSTRACT FROM AUTHOR]

Previous studies of the Doce River basin (Brazil) seem to be contradictory regarding the contamination of soils with potentially harmful elements (PHE). This research aimed to perform an integrated assessment of PHE in the soil–plant–tailing system from the area most affected by the iron waste after the Fundão Dam disaster in 2015. Different fractions of PHE (exchangeable, nonexchangeable, reducible, and pseudo‐total) were determined on deposited iron waste (DIW), soil waste mixture (SWM), and control soil (CS) samples. Total contents of PHE in Poaceae were also determined, and Allium cepa bioassays were performed to determine DIW and CS cytotoxicity and/or genotoxicity to plants. The Fe and Mn contaminations were the only ones related to the deposition of DIW on floodplains, and other harmful element content (such as As, Hg, Ni, Cd, Cr, and Pb) was not found above baseline values for soils. In addition, a significant part of the Fe and Mn in DIW is readily available or subject to acidification and prolonged flood reduction processes. The high available content of Fe favored its excessive accumulation by Brachiaria. The DIW chemical conditions reduced biological functions of A. cepa under a controlled environment. However, more drastic effects, such as genetic damage, were not seen. The postdisaster action of covering DIW with CS resulted in undesirable enrichment of Pb on the floodplain soils. The integrated results allow the conclusion that the iron waste is not a time bomb for PHE contamination of soils between the Fundão and Risoleta Neves Hydroelectric Dam (~100 km away from Fundão). Integr Environ Assess Manag 2024;20:117–132. © 2023 SETAC Key Points: There was no contamination of Al, Ag, As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Sb, Se, Sn, Pb, and Zn on deposited iron waste (DIW).Fe and Mn contamination in DIW was found, and Mn was readily bioavailable; high levels of Fe were detected in Brachiaria.Genetic damage assessed by a bioassay with Allium cepa seeds has not been observed.Covering DIW with control soil resulted in undesirable enrichment in Pb on the floodplains. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Production Engineering / Revista Brasileira de Engenharia de Produção is the property of Brazilian Journal of Production Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bacillus cereus is a Gram-positive bacterium commonly reported in soils and plants that occupy various ecological habitats, and the main source of contamination for cattle is silage. This report described a case of fetal loss associated with B. cereus infection in a cow. An 8-month-old, Nelore female bovine fetus from a beef farm was submitted for necropsy. A gross examination revealed fibrinous pleuropneumonia and fibrin exudation on the liver surface. The morphological diagnosis was restricted to the lungs and liver. In the lungs there was fibrinosuppurative pleuropneumonia associated with numerous aggregates of rod-shaped bacteria. In the liver there was moderate focally extensive fibrinous peri hepatitis.The lungs, liver, thoracic, and abomasal fluid cultures yielded pure cultures of B. cereus, indicating that these bacteria should be recognized as a cause of bovine abortion in fetuses that macroscopically present fibrin in the abdominal and thoracic cavity. [ABSTRACT FROM AUTHOR]

Despite the exceptional species richness and endemism, the environmental drivers of plant diversity along old tropical mountains remain under-explored. The respective importance of vegetation types, elevation, slope, and soil to drive diversity across life-forms is poorly addressed. Here, we tested whether environmental variables drove local and regional plant diversity along an old tropical mountain according to the three main life-forms: graminoids, herbaceous and woody species. We sampled all Angiosperm species on 180 plots across five elevations, at the tropical old-mountain region of Serra do Cipó, South-eastern Brazil. We assessed soil, slope, and vegetation types, and calculated richness and beta-diversity, applying generalized least square models, linear mixed-models and partial Mantel tests to test for relationships. Richness of graminoids and herbaceous species increased with greater elevation and more nutrient-impoverished soils, while woody richness showed the inverse pattern. Beta-diversity was primarily driven by species turnover, correlated with elevation and soil and higher in less dominant vegetation types, with unique species. Despite the limited elevational range in these old mountains, it still played an important role in filtering woody species, while fostering graminoid and herbaceous species. Conservation and restoration actions need to foster the high regional diversity supported by the old mountain heterogeneous landscape and the diversity of life-forms, especially the dominant and highly diverse grassy component. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the coronavirus (SARS-CoV-2) pandemic and the impossibility to carry out the extension projects Earth Science Workshop (Oficina da Ciência da Terra) and Truck with Science (Caminhão com Ciência), the Soil Tutorial Education Program (PET Soils) from State University of Santa Cruz (UESC, Brazil), resorted to production, divulgation, and availability of didactic materials to spread the Soil Science. Five graduation students in Agronomy (scholarship holders from PET Soils) and a university professor (tutor of the group), in weekly meetings, defined the topics, content, and the way of scientific language transposition used on the extension actions of the group. Were outlined two booklets ("O Universo abaixo dos nossos pés" - The Universe below our feet, and "O solo e as plantas: uma íntima relação" - The soil and the plants: an intimate relationship) and three education games ("Jogo da memória" - Memory game, "Passe e repasse" - Pass and repass, and "Que solo sou eu" - What soil am I). The visual production was developed on Canva -visual and audiovisual software development- and the illustrations on Paint Tool SAI software. The didactic material produced was spread on Instagram, Youtube (PET Solos UESC, Brazil) and available for download. Until the day 2021, October 20th, the divulgation registered 675 and 239 visualizations on Instagram and Youtube, respectively. The didactic materials were applied on workshops, monitories, and classes of Pedology on UESC, reaching 310 assisted students until the date above. In this sense, its coverage and reach have been promoting expanding the knowledge about soil and represent an effective contribution to soil education in a pandemic scene. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The beetroot is widely grown in Brazil, but little is known about its fertilization with sulfur (S). To evaluate the response of the beet culture to different doses of elementary S (0, 30, 60, 90, 120, and 150 kg ha-1), a randomized block experiment was carried out in Cambisol soil distributed in beds with 1,0 m wide x 5.34 m long. The soil pH was corrected to 6.0; and 100 kg ha-1 of N (in two doses), 380 kg ha-1 of P2O5, and 180 kg ha-1 of K2O were applied. The evaluations were carried out at 60 DAS (days after sowing), fresh and dry mass of leaves and roots are used. Subsequently, the tissues were ground and subjected to nitro-perchloric digestion. For the analysis of S in the soil, samples were collected up to 20 cm deep, dried, ground, and sieved in a 2 mm mesh, determining the available S-SO4-2 after nitroperchloric digestion. The S content in the tissue and in the soil was determined in the solution in a spectrophotometer (440nm), by turbidimetry. The beet plants grown in the soil with the addition of 60 kg ha-1 of S showed the highest production of the fresh and dry mass of beetroots. Adequate S levels in the soil were approximately 10 mg dm-3, higher than 5.0 mg dm-3 considered high by the culture recommendation. With the application of 30 kg ha-1 of S it was observed a greater fresh and dry leaf mass, and export of S in leaf and roots. [ABSTRACT FROM AUTHOR]

The Mehlich-1 extractor is the most used in Brazil, however it extracts low phosphorus (P) levels in soils with high clay levels and iron-bound (Fe) and aluminum (Al) fractions. Thus, we aimed to evaluate the P availability and fertility classes in Yellow Latosol (YL) and Gleysol Haplicum (GH) soils using Mehlich-1, Mehlich-3 and anion exchange resin extractors, as well as to estimate the critical P levels in the soil and in plants for establishing Urochloa humidicola cv. Common. All extractors were efficient in evaluating the availability of P in the soil, however the anion exchange resin showed a high correlation with the P accumulation in the shoot, which can be considered the most efficient method in P extraction. However, we recommend the Mehlich-3 extractor due to its high efficiency in extracting the P linked to the Fe and Al fractions, in addition to being a multi-element extractor. The critical level of P in the soil for establishing U. humidicola by Mehlich-3 in YL is 10.32 mg dm-3, while it is 7.46 mg dm-3 in GH. The critical P level in plants grown in YL is 1.20 mg dm-3, and it is 1.54 mg dm-3 in GH. The estimated phosphate doses can be recommended for cultivating U. humidicola and can serve as a reference for future research on correlating and calibrating P doses. [ABSTRACT FROM AUTHOR]

In semiarid region of Irecê, state of Bahia, Brazil, there are superficial elongated strips in form of lateritic crust derived from hydrothermal weathering of sulfide known as "gossans" with heavy metals anomalies. Thus, this study aimed to evaluate the presence and concentration of metals As, Cd, Pb, Cu, Cr, Fe, Mn, Ni, Ti, and Zn in different parts of cultivated and native plants in "gossan" area and relationship with soil content, in an area that has been used for decades by small family farmers for the crops production and raising small animals. The metals were analyzed by ICP-OES in plant and soil extracts obtained after acid digestion (USEPA SW-846 3050B). As, Cd, and Ni were not found in the evaluated plants. Pb, Fe and Ti concentrated in the roots of several plants, with emphasis on buffel grass (Pb and Fe) and corn and white pinion (both Fe and Ti). Zn and Mn were distributed in all parts of plants evaluated. Cu levels found were quite below of phytotoxic levels. Significant positive correlation between lead in root and soil and negative between lead in stem, leaf, and soil were observed, indicating a plant protection mechanism concentrating lead in the root without translocating it to the aerial part. Similar behavior has occurred in relation to Cu, concentrating it in the root and fruit. Fortunately for the farmers and consumers, the highest concentration of heavy metals was observed in the roots of both cultivated and native plants. [ABSTRACT FROM AUTHOR]

Copyright of Integrated Environmental Assessment & Management is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phytolith reference collections of plants and surface soils are a critical part of studies that use these microbotanical remains for archaeological and paleoecological reconstruction. In the archaeologically-rich region of the Upper Madeira river in Rondônia, Brazil, phytolith analysis is being applied in both on- and off-site contexts in order to shed light on human-environment interactions over a period that extends almost the entire Holocene. The present study brings together data on phytolith production patterns among 90 native species, representing 36 plant families, as well as 56 surface soil samples taken from underneath 11 monitored forest plots. Our discussion focuses on the comparison between the surface soil phytolith records and the above-ground floristic inventories, scrutinized considering the plant reference collection results. We found that the phytoliths of several species which produce diagnostic or potentially-diagnostic morphotypes were under-represented in the surface soils, including several understory herbs. While the phytolith assemblages from three forest types (palm, sororoca and dense forest) presented considerable overlap, in accordance with similarities in the floristic inventories, bamboo forest and different types of campinaranas were able to be distinguished based on their phytolith signatures. [ABSTRACT FROM AUTHOR]

Since arsenic (As) exposure is largely due to geochemical contamination, this study focused on the remediated area of Santana do Morro, a district of Santa Bárbara, Minas Gerais, Brazil, which was previously contaminated with As due to gold mining. Total As concentrations in sediment, soil and plants were determined, next to As species, anionic arsenic compounds As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), in plants samples. Total As concentrations in soil and sediments were slightly elevated (16-18 µg g-1) and most of the plants contained low levels of As (< 1 µg g-1). The exception was a native plant Eleocharis geniculata (L.) which contained elevated levels of As (4 µg g-1). The exposure of this plant to As under controlled conditions (hydroponics) indicated its possible tolerance to elevated As levels and suggesting its potential use in phytomonitoring of As-contaminated sites. This plant is able to metabolize arsenate to arsenite and contained MMA and DMA, both in its natural habitat and under controlled conditions. [ABSTRACT FROM AUTHOR]

Polyhalite, a source of potassium (K) and other nutrients, has been suggested as an alternative to fertilizer in Brazil. Two greenhouse pot experiments were carried out to evaluate the agronomic efficiency of polyhalite as a K and multinutrient source. Soil samples were collected from the Brazilian Cerrado. Pots were filled with 2 kg of soil. Treatments were composed of muriate of potash (MOP) and polyhalite was applied at rates of 20, 40, 80, 120, 160, and 200 mg K kg−1 soil in experiment I. A mix of soluble sources of K, sulfur (S), calcium (Ca), and magnesium (Mg) was compared to polyhalite at the same rates of 0.33, 0.66, 1.33, 2.00, 2.66, and 3.33 g pot−1 in experiment II. After 45 days of vegetative corn growth, plants and soil were collected. In experiment I, rates of K influenced yield of corn dry matter, but not the source of K. Corn dry matter yield in experiment II was higher with polyhalite. Polyhalite was similar or superior to conventional sources and was highly efficient at supplying K, Ca, Mg, and S to plants. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The central-north of Brazil is a region with strong presence of concrectionary soil, whose supposed disadvantages from the agronomic point of view, do not prevent their use in agriculture. However, more in-depth information about the behavior of crops of agricultural interest cultivated in this type of soil is few. Due to the observation of agricultural stands in this type of soil, it was hypothesized that plinthite ironstones concretions negatively interfere in the development of crops of agro-economic interest. The objective was to verify the growth and development of soybean cultivated in soil with the presence and absence of plinthite ironstones. Concretionary Petric Plinthosol were collected in the 0-0,20 m layer and part of the soil was sieved so that concretions larger than 3.10 mm in diameter were removed, thus leaving two treatments, soil with and without plinthite ironstones. Morphological evaluations were performed during their phenological phase. Soybean grown in soil without ironstones showed higher growth at 32 and 48 DAE and more leaflets when compared to soy crop grown in soil with ironstones. As for dry matter, soybean grown in soil without ironstones showed more values for aerial, root and total mass as well for aerial root rate when compared to soybean grown in soil with ironstones. Plinthite ironstones interfere with the growth and/or vegetative development of soybeans. Soybean has less vegetative development when grown in soil with plinthite ironstone concretions. [ABSTRACT FROM AUTHOR]

BACKGROUND Several factors may degrade pastures, in particular, inadequate nutrient application and spittlebug attacks. Mahanarva spectabilis (Distant, 1909) (Hemiptera: Cercopidae), one of the species that occur in Brazil, is a limiting pest in forage production. This study analyzes the influence of fertilization with the macronutrients nitrogen, phosphorus and potassium (NPK) on the survival of M. spectabilis nymphs, and the effects of damage by nymphs and adults on the production, quality and regrowth capacity of the forages Brachiaria ruziziensis, Pennisetum purpureum and Digitaria sp. RESULTS: Fertilization of the forages differentially affected damage due to spittlebug herbivory. Attacks by nymphs and adults decreased chlorophyll content, plant regrowth and forage quality, and increased injury, regardless of fertilization. The availability of nutrients in the soil not only decreased fiber content, but also increased crude protein, chlorophyll content and regrowth, even when pest infested. Soil fertilization increased the capacity of forage plants to lessen, albeit not eliminate, the effects of injury by M. spectabilis. CONCLUSION: Forages in fertilized soil are more tolerant to attacks by M. spectabilis nymphs and adults. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, a principal component analysis was performed to evaluate the possibility of discarding obsolete soil and plant variables in a coffee field to eliminate redundant and difficult-to-measure information in precision coffee farming. This work was conducted at Brejão Farm in Três Pontas, Minas Gerais, Brazil, in a coffee field planted with 22 ha of Topázio cultivar. The evaluated variables were the yield, plant height, crown diameter, fruit maturation index, degree of fruit maturation, leafing, soil pH, available phosphorus (P), remaining phosphorus (Prem), available potassium (K), exchangeable calcium (Ca2+), exchangeable magnesium (Mg2+), exchangeable acidity (Al3+), potential acidity (H + Al), aluminium saturation (N(Al)), potential CEC (CECp), actual CEC (CECa), sum of bases (SB), base saturation (BS) and organic matter (OM). The data were evaluated by a principal component analysis, which generated 20 components. Of these, 7 representing 88.98% of the data variation were chosen. The variables were discarded based on the preservation of the variables with the greatest coefficients in absolute values corresponding to the first component, followed by the variable with the second highest absolute value corresponding to the second principal component. Based on the results, the variables V, OM, fruit maturity index, plant height, yield, leafing and P were selected. The other variables were discarded. [ABSTRACT FROM AUTHOR]

Highlights • SMAF is sanative to soil quality (SQ) assessment under sugarcane straw removal in the short-term. • Oxisol responds faster to sugarcane straw removal than Ultisol. • Indiscriminate straw removal for bioenergy production leads to Oxisol physical quality degradation even in the short term. • Straw and stalk yields are correlated to soil-physical attribute and SQ. • Actions should be taken to enhance soil-physical attribute and overall SQ. Abstract There is a growing interest by the Brazilian sugarcane (Saccharum sp.) industry in removing sugarcane straw from the field to use as raw material for increasing bioenergy production (e.g. , second generation and co-generation). In contrast, straw has an essential role in sustaining critical soil functions, so indiscriminate straw removal can jeopardize soil quality and consequently reduce crop yield. The objectives of this study were: (i) to apply the Soil Management Assessment Framework (SMAF) tool to investigate the short-term effects of sugarcane straw removal on a sandy clay loam Oxisol and on a sandy loam Ultisol, and (ii) to correlate soil quality attributes (i.e., chemical, physical and biological) and the overall Soil Quality Index (SQI) with plant yield (straw and stalk) in areas managed with straw removal. A 2-year experiment was conducted in a randomized block design replicated four times with three rates of straw removal: 0, 50 and 100% (i.e., no removal, moderate removal, and total removal, respectively). Soil samples were collected at the 0–5, 5–10, 10–20 and 20–30 cm layers and following indicators were analyzed: physical [bulk density (BD)], chemical [soil-pH, phosphorus (P) and potassium (K) content] and biological [soil organic carbon (C) and microbial biomass carbon (MBC)]. For the Oxisol, 100% straw removal decreased soil physical attribute scores (i.e. bulk density) in 5–10 and 10–20 cm depths and decreased SQI in the 0–20 cm depth, while the 0% and 50% straw removal rates enhanced SQIs in all depth increments. Furthermore, 50% straw removal sustained soil quality and increased feedstock availability for bioenergy production. Straw and stalk yields were correlated to soil physical attribute score and SQI for 0–10 cm soil depth in the Oxisol. For the Ultisol, straw removal did not influence SQI and there was no relationship between soil quality scores and phytomass. Our results highlight soil-specific responses to sugarcane straw removal and total straw removal in the Oxisol site leads to physical quality degradation even in the short term. Despite no short-term effect of straw management on Ultisol soil quality, the long-term benefits of the straw on the soil-plant system may be reduced with total removal, thus indiscriminate straw removal is not advocated. Based on our findings, partial straw removal can be a win-win scenario in Brazil, where a considerable volume of biomass can be used for bioenergy production with minimal impacts on soil quality. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and aims: While the role of deep roots in major ecosystem services has been shown for tropical forests, there have been few direct measurements of fine root dynamics at depths of more than 2 m. The factors influencing root phenology remain poorly understood, creating a gap in the knowledge required for predicting the effects of climate change. We set out to gain an insight into the fine root phenology of fast-growing trees in deep tropical soils. Methods: Fine root growth and mortality of Eucalyptus grandis trees were observed fortnightly using minirhizotrons down to a soil depth of 6 m, from 2 to 4 years after planting. Results: In the topsoil, the highest live root length production was during the rainy summer (20 cm m d) whereas, below 2 m deep, it was at the end of the dry winter (51 cm m d). The maximum root elongation rates increased with soil depth to 3.6 cm d in the 5-6 m soil layer. Conclusions: Our study shows that the effect of the soil depth on the seasonal variations in fine root growth should be taken into account when modelling the carbon, water and nutrient cycles in forests growing on deep tropical soils. [ABSTRACT FROM AUTHOR]

Vegetable oils are widely used for food production at different levels: domestic, commercial or industrial. The estimated production of vegetable oil, in Brazil, is three billion liters per year. Only 2.5% of cooking oil waste (WCO) are recycled. The environmental impacts caused by WCO arrangement in soils still need to be better studied. The interaction of soils and organic pollutants makes it difficult to evaluate its behavior in the environment. This paper presents to evaluate the environmental impact of OVR in two Brazilian soils (sandy and loamy) and to estimate the terrestrial toxicity level (leakage test) and phytotoxicity (germination tests using lettuce seeds - Lactuca sativa L. - as well as in lettuce cultivation under greenhouse conditions). After leaching, the sandy soil had a slight lower WCO adsorption capacity than the clayey soil. The introduction of WCO caused clayey soil compaction. The WCO presence was toxic to earthworms, regardless of soil type. WCO negatively influenced germination and radicle growth in the eco toxicity assays. The different tested doses of WCO in lettuce (Lactuca sativa L.) cultivation caused changes in plant morphology for all physical parameters analyzed for both soils. We concluded that the WCO is a potential contaminant residue when improperly disposed over the soil, compromising the soil-plant system. [ABSTRACT FROM AUTHOR]

The Brazilian cerrado occurs interspersed with the semi-deciduous seasonal forest, and soil fertility is considered as the main determinant of the abrupt transitions between both vegetation types. We aimed to study patterns across chemical traits of green leaves in 121 cerrado and seasonal forest woody species from southeastern Brazil, their response to soil nutrient status, and their effects on decomposition rates. We compared leaf traits of both cerrado and forest species and constructed multilevel models to account for partitioning of variance in each trait. We calculated the community-weighted mean of each trait to assess their response to soil nutrient status and their effects on decomposition rates of standard plant material. Most of the traits were significantly correlated among themselves, with cerrado species having lower nutrient concentrations than the seasonal forest. Taxonomy accounted for 52 % of the total variance in leaf traits, whereas vegetation type accounted for 19 %. All leaf traits but leaf manganese and aluminium concentrations were significantly related to soil properties. Decomposition rates were affected indirectly by soil features through its effects on leaf traits. Contrary to the expected, the higher the leaf nitrogen concentration in the surrounding litter, the lower the decomposition rate. Even with a large effect of taxonomy on leaf nutrient-related traits, soil exerted an important role on the chemical traits. Strategies of both cerrado and seasonal forest species were carried out through multi-element control of soil on leaf nutrient composition. The effect of such different strategies on functioning was, however, less prominent. [ABSTRACT FROM AUTHOR]

Aims: We investigated how outcrops of different geological origins enhance the plant megadiversity of the Atlantic rainforest hotspot. Methods: We collected vegetation, topographic, and soil fertility data from 50 2 m plots in each of nine rock outcrops (three ironstones -or cangas, three quartzites and three granitoids) in the Iron Quadrangle, SE Brazil. We examined the response of community diversity and structure patterns to edaphic and topographic gradients by means of diversity profiles, clustering and ordination analyses. Species were organized into nine functional groups. Results: We inventoried 17,690 individuals belonging to 352 species. Functional groups with largest cover were sclerophytic shrubs (in cangas), graminoid and poikilohydric herbs (in both granitoids and quartzites). Granitoid plant communities were the least diverse, on account of fewer substrate types leading to more xeric conditions. The multivariate analyses sorted the outcrops by geological origin, although within-lithotype similarity was low. There was stronger similarity between cangas and quartzites, separated from granitoids. Soil was nutrient-poor, and variables most influencing this pattern were number of substrates, topographic heterogeneity, soil depth, and aluminum saturation. Conclusions: Saxicolous plant communities responded more strongly to microtopographic than soil fertility parameters. Each lithotype contributes differently to the high alpha- and especially beta-diversity within the Atlantic Rainforest matrix. [ABSTRACT FROM AUTHOR]

(Oomycota from 'Parque Estadual da Ilha do Cardoso' (PEIC): first records for São Paulo State and Brazil). We studied the oomycetes diversity from soil and freshwater samples collected quarterly from August 2012 to June 2013 at 'Parque Estadual da Ilha do Cardoso' (PEIC), São Paulo State, Brazil. Among the species identified by morphological and/or molecular (complete ITS rDNA region) analysis, four are recorded for the first time for Brazil: Araiospora streptandra var. streptandra Kevorkian, Achlya primoachlya (Coker & Couch) TW Johnson and RL Seym., Aplanopsis terrestris Höhnk and Saprolegnia aenigmatica Sandoval-Sierra & Diéguez-Uribeondo and three for São Paulo State: Achlya crenulata Ziegler, Brevilegnia longicaulis TW Johnson and Saprolegnia truncata RL Seym. All species are described, commented and illustrated herein. The specimens were deposited in the culture collection of the 'Instituto de Botânica (CCIBt)' and/or in the Herbarium SP. The ITS rDNA sequences obtained were deposited in the GenBank. [ABSTRACT FROM AUTHOR]

Interactions between soil characteristics and soil microbiota influence soil ecosystem processes such as nitrification however, their complexity makes interpretation difficult. Furthermore, the impact of soil management systems on abundance and activity of soil microbial community is poorly understood, especially in the Neotropics. To investigate these interactions, the effects of tillage, inorganic fertilization, and plant cover on the abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were assessed by quantification of the marker gene ( amoA) during different stages of soybean cultivation in a site under restoration from gravel extraction in the Central Brazilian Savanna (Cerrado). Results of molecular analysis and classic and isotope techniques showed that levels of organic C and NH-N were higher in the soybean field during fallow than in an adjacent undisturbed field (Campo sujo). Ammonia oxidizer abundance and nitrification rates were also higher in the agricultural soil than in the undisturbed site, with the lowest ammonium/nitrate ratio in tilled soil. Soil δ15N was lower in the undisturbed soil than the agricultural soil. Both AOA and AOB were more abundant during soybean crop transitional stages, and this increase positively correlated with soil pH, particularly for AOB abundance, in tilled soil and within the soybean rhizosphere. The results suggest that AOB have more copiotrophic characteristics than AOA and are better able to change available ammonium in the soil. The combination of standard soil ecological methods and modern molecular analysis show the short-term modification of ammonia oxidizer abundance and soil N dynamics in a managed system within the Cerrado biome. [ABSTRACT FROM AUTHOR]

The Cerrado biome covers a large area of central Brazil, containing a mosaic of physiognomies determined by soil fertility, seasonal rainfall, and fire. The ground layer vegetation presents a high eudicot diversity and a high proportion of belowground phytomass, represented mainly by a diversity of underground organs storing carbohydrates. Fructans and other soluble carbohydrates are claimed to be more than reserves, conferring protection against abiotic stresses due to osmoregulation properties and rapid turnover. Inulin- and levan-type fructans are prominent and found respectively in the underground organs of Asteraceae and Amaranthaceae, abundant families in the herbaceous Cerrado flora. Poaceae, mainly Panicoideae, is also abundant and accumulates glucose, sucrose, and malto-oligosaccharides, but not fructans, in contrast with temperate grasses. Here, we review evidence that fructans in the herbaceous flora of the Cerrado play a significant role in tolerance to drought and fire, promoting the rapid recovery of the ground-layer vegetation after environmental disturbances. [ABSTRACT FROM AUTHOR]

Nutrient limitation in Brazilian savanna (known as cerrado) presumably causes trees to maximize nutrient resorption from senesced leaves to reduce their dependence on nutrient availability. To assess patterns between nutrient resorption and soil fertility, we measured community-level nitrogen (N), phosphorus (P), and potassium (K) concentrations in mature and senesced leaves and soil fertility in the upper 50 cm soil layer in structurally diverse cerrado ecosystems in the Cuiaba Basin (CB) and Pantanal (PAN) of Mato Grosso, Brazil. Foliar nutrient concentration data were used to estimate resorption efficiency and proficiency, and correlation was used to determine whether resorption efficiency and proficiency varied across soil fertility gradients. We found that N and P resorption proficiency (NRP and PRP, respectively) and P resorption efficiency (PRE) increased significantly as total soil N (NRP) and extractable P (PRP and PRE) declined. In contrast, K resorption efficiency (KRE) declined as soil sand content and bulk density increased, which was likely due to a reduction in soil water-holding capacity. Leaf N/P ratios indicate potential N limitation and/or N + P co-limitation for ecosystems in the PAN and P limitation and/or N + P co-limitation for ecosystems in the CB, while trends in leaf N/K ratios indicate possible K or K + P co-limitation for the CB only. Our results illustrate that cerrado forests and woodlands have highly variable nutrient resorption capacities that vary predictably across soil fertility or textural gradients and indicate that cerrado communities have flexible nutrient resorption that can reduce their dependence on soil nutrient availability. [ABSTRACT FROM AUTHOR]

Solar radiation is a meteorological component of great importance to soil-plant-atmosphere processes, and the majority of weather stations do not register this component since they do not have the equipment for its quantification. The objective of this study was to evaluate the efficiency of models to estimate solar radiation for the annual, rainy and dry periods in Aquidauana "Alto Pantanal" region of Mato Grosso do Sul, Brazil. This study was conducted using meteorological data obtained from January 2008 to December 2011. The automatic meteorological station was located in Aquidauana, and belongs to the network of the Instituto Nacional de Meteorologia (INMET). The data collected included maximum and minimum temperatures, and solar radiation. The Annandale, Bristow-Campbell, Hargreaves-Samani and Weiss empirical models were evaluated, and all were compared with the solar radiation value measured by the meteorological station. In Aquidauana, the Alto Pantanal region of Mato Grosso do Sul, regardless of the time of year, the Bristow-Campbell model is recommended to estimate solar radiation. [ABSTRACT FROM AUTHOR]

Although the high diversity of plant species in the rupestrian fields has been primarily attributed to the existence of a set of distinct habitats, few studies support this assertion. The present study aimed to further investigate the relationship between physical and chemical attributes of soils with the diversity of plant species in this unique ecosystem. The rupestrian field is a unique vegetation formation that covers some of the southeastern Brazilian mountains in the transition of the Atlantic rain forest and the Cerrado (savanna). Different habitats occur according to soil characteristics (e.g., presence of rocks, sand, fertility, hydrology, etc.). These attributes ultimately influence the vegetation that is highly adapted to the harsh edaphic and climatic mountain conditions. Five distinct habitats were studied by us: rocky outcrops, peat bogs, sandy bogs, quartz gravel fields, and 'cerrado' (savanna). A floristic survey indicated that four families are found at greater frequency: Poaceae, Asteraceae, Cyperaceae, and Leguminosae. The greatest diversity of plant species was found in the rocky outcrops habitat, followed by cerrado, peat bog, quartz gravel grassland, and sandy bogs, respectively. The main difference in the floristic composition among these habitats was related to the dominant species. Trachypogon spicatus (Poaceae) was the most dominant species in the rocky outcrops, Axonopus siccus (Poaceae) in the peat bogs, Lagenocarpus rigidus (Cyperaceae) in the sandy bogs, Schizachyrium tenerum (Poaceae) in the cerrado, while Vellozia sp. 8 (Velloziaceae) dominated the vegetation in the quartz gravel grassland. This study demonstrated that physical and chemical soil properties strongly related the diversity of plant species occurring in the different habitats of rupestrian fields. [ABSTRACT FROM AUTHOR]

Campo rupestre is a kind of Brazilian rocky outcrop with high biodiversity and many endemic and threatened species. It occurs mainly in the Espinhaço Range in a contact region between Cerrado and/or Caatinga and Atlantic Forest. The Espinhaço Range is recognized as a region with the highest floristic diversity in South America and with many endemic species, most of which are associated with rocky outcrop environments. These, among other peculiarities, recently granted the Espinhaço Range the status of Biosphere Reserve. The relationship between soil and vegetation was studied in campo rupestre areas with quartzite and itabirite rocks. Three habitats in both lithologies were defined by geomorphology as: 1. Slopes with grasslands; 2. Plateaus with grasslands and 3. Valleys with woody savannas. In each lithology, 30 plots (10 × 10 m), 10 in each habitat, were defined. The species and their respective coverage were recorded and soil was sampled to perform chemical and physical analyses. The analyzed soils were similar in being sandy, acidic and with low fertility. Nevertheless, they exhibited differences in chemical and physical properties. Altogether there were 272 species, belonging to 70 families. The canonical correspondence analysis of soil variables and species coverage showed a clear segregation of lithological sites due mainly to the exchangeable content of Ca, Cu, Mg, Mn and S; soil particle size - central tendency and sorting; and the percentage of silt, fine soil and bare rocks. A strong correlation between plant species coverage and soil properties was also found. [ABSTRACT FROM AUTHOR]

Abstract: The use of cover crops affects the support capacity of soil and least limiting water range to crop growth. The objective of this study was to quantify preconsolidation pressure (σ p), compression index (CI) and least limiting water range (LLWR) of a reclaimed coal mining soil under different cover crops, in Candiota, RS, Brazil. In the experiment, with randomized blocks design and four replicates, the following cover crops (treatments) were evaluated: Hemarthria altissima (Poir.) Stapf & C.E. Hubbard, treatment 1 (T1), Paspalum notatum Flüggé, treatment 4 (T4), Cynodon dactilon (L.) Pers., treatment 5 (T5), control Brachiaria brizantha (Hochst.) Stapf, treatment 7 (T7) and without cover crop treatment 8 (reference treatment, T8). Soil compression and least limiting water range were evaluated with undisturbed samples at a depth of 0.00–0.05m. In order to evaluate parameters of soil compressibility, the soil samples were saturated with water and subjected to −10kPa matric potential and then submitted to a uniaxial compression test under the following pressures: 25, 50, 100, 200, 400, 800 and 1600kPa. Cover crops decreased the preconsolidation pressure of constructed soils after coal mining and the greatest soil reclamation was obtained with the H. altissima cover crop, where the lowest degree of soil compactness and soil load capacity were observed. Soils cultivated under H. altissima or B. brizantha presented the highest least limiting water range and these two cover crops generated similar soil critical bulk density obtained by least limiting water range and soil load support capacity. [Copyright &y& Elsevier]

The purpose of this work was to study the percentage of healthy trees, living trees and healthy branches and the renewal (natural propagation) of Caryocar brasiliense associated with the properties of soil, the floristic diversity and the canopy size of this plant. Lower proportions of live C. brasiliense trees and of healthy branches were found in the Savanna of Ibiracatu, where only 30% of the trees were healthy and without visible signs of attack by wood borers and by Phomopsis sp. We observed that C. brasiliense trees in areas where the soils contained higher levels of summed chemical bases and total sand (fine + gross) were less healthy. Moreover, the areas whose soils contained higher levels of aluminum and clay had a higher percentage of healthy C. brasiliense trees and branches. Smaller percentages of live and healthy trees and healthy branches were noted in areas with higher floristic diversity. Overall, the higher mortality of C. brasiliense trees may be associated with a higher pH and a lower content of aluminum, silt and clay, with competition with other tree species for nutrients, water and light, with the attack of Cossidae and particularly with the attack of fungi, Phomopsis sp. [ABSTRACT FROM AUTHOR]

Distribution ranges of plant species are related to physical variables of ecosystems that limit plant growth. Therefore, each plant species response to physical factors builds up the functional diversity of an ecosystem. The higher the species richness of an ecosystem, the larger the probability of maintaining functions and the higher the potential number of plant functional groups (FGs). Thus, the richness potentially increases the number of functions of the highly diverse Atlantic Rainforest domain in Brazil. Severe plant growth limitations caused by stress, however, decrease species richness. In the Spodosols of the Mussununga, an associated ecosystem of Atlantic Rainforest, the percentage of fine sand is directly related to water retention. Moreover, the depth of the cementation layer in the Mussununga's sandy soil is a physical factor that can affect the plants' stress gradients. When a shallow cementation layer depth is combined with low water retention in soils and with low fine sand percentage, the double stresses of flooding in the rainy season and water scarcity in the dry season result. This study aimed to identify FGs among Mussununga plant species responding to water stress gradients of soil and to verify the effects of the gradients on plant species richness of the Mussununga. A canonical correspondence analysis (CCA) of species abundance and soil texture variables was performed on 18 plots in six physiognomies of the Mussununga. Species richness rarefactions were calculated for each vegetation form to compare diversity. The two main axes of the CCA showed two FGs responding to soil texture and cementation layer depth: stress tolerator species and mesic species. Physical variables affect plant diversity, with species richness rising as the fine sand proportion also rises in the Mussununga. The effect of the cementation layer is not significantly related to species richness variation. [ABSTRACT FROM AUTHOR]

We characterized and compared the use of nitrate (N-NO3-), in three recognized pioneer and secondary tropical species, analyzing their relationships with the availability of inorganic nitrogen in the soil of a riparian forest. We tested the hypothesis that pioneer species of the ecological succession (Cecropia glaziovi - Cgl) would be more responsive to N-NO3- available and would have high nitrate reductase activity (NRA) in leaves while secondary species (Inga marginata - Ima and Hymenaea courbaril - Hco) would have less responsiveness and would have lower levels of this enzyme on its leaves. We evaluated, tested and compared the NRA and N-NO3- content in leaves and xylem sap of each species. We measured N-NO3- and N-NH4+ content in the soil. The results for Cgl showed an N-NO3- content of xylem sap that met the demand of NRA and were correlated with inorganic soil nitrogen, showing the responsiveness of species to N-NO3-. Hco was verified as less responsive to assimilation and high N-NO3- content in leaves. The species Ima showed an intermediate behaviour, which suggests the possibility of use of other nitrogen forms. The ecophysiological behaviours of the plants were related to the seasonal variation and indicate that these plants use strategies with different responsiveness to the use of soil N-NO3-. In this sense and considering that these species are typically used in ecological restoration projects in Brazil, the knowledge of a strategy for nitrogen use specific to each of them can assist in choosing the species appropriate to the edaphic conditions of the environment. [ABSTRACT FROM AUTHOR]

Abstract: Soil, drought, and fire are abiotic factors that may act as environmental filters in the cerrado, the Brazilian savanna. We used a framework to analyze environmental filtering in geographic and phylogenetic context, sampling woody species in one of the largest cerrado reserves. In 100 quadrats, we measured 10 functional traits on each woody individual. We also measured several soil variables, altitude and slope as a rough surrogate of water availability, interval between fires, and time since last fire. Almost all environmental variables were spatially auto-correlated. We found an overall trait clustering, but not an overall phylogenetic clustering. Nevertheless, we found a phylogenetic signal for some traits. Linking phylogeny, traits, environment, and space, we were able to detect a major dichotomy between two geomorphological units. The flat tableland was positively related with altitude, fire frequency, and nutrient-richer soil. Environmental filtering caused by water availability and fire lead to trait clustering, with smaller shrubs and trees that presented thicker barks, denser woods, sclerophyllous leaves, highlighted by the prevalance of Myrtaceae. The other geomorphological unit, hilly terrain, was positively related with slope, low fire frequency, and nutrient-poorer soil. Environmental filtering was caused especially by nutrient-poor soil that lead to trait clustering, assembling taller trees, with thinner barks, lighter woods, and compound, large, tender, nutrient-richer leaves, distributed across many lineages, including Fabaceae. Hence, the high environmental variability in space with different environmental filters assembled different combination of plant traits and lineages, increasing the overall diversity in cerrado. [Copyright &y& Elsevier]

This study aimed to measure the variation of soil and leaf water potential in the Sugraone (Superior Seedless) grape, as well as the berry growth, under different irrigation conditions in the Fazenda Agrobrás Tropical do Brazil S/A, in Casa Nova, BA, in October, 2007 during maturation stage. The Superior Seedless cultivar was irrigated at 21, 13 e 5 days before harvest with water depths of 100, 50 e 0% of crop evapotranspiration (ETc) and an additional treatment consisting of the farmer management. The results of leaf water potential using a pressure chamber and the respective soil matric potential from tensiometric readings are shown. Measurements of leaf water potential reached values from -0,95 to -1,80 MPa, at noon and from -0,10 to -0,27 MPa, at pre-dawn. Soil water matric potential varied from -5 to -79,5 kPa, for the least water deficient treatments. Results from leaf water potential show that in some days the plants were under moderate stress and in others under severe stress, independently of water deficit treatments. Although pre-dawn leaf water potential indicated that the vines were under mild stress or under adequate water management practices, even under low soil matric potentials, there was no significant reduction in berry growth. [ABSTRACT FROM AUTHOR]

The main cadmium exposure pathway for humans is through diet. A database on Cd concentration in soils and accumulation in edible vegetables from tropical and temperate regions was organized, soil-plant relationships were derived, and then critical soil Cd concentrations were calculated based on human exposure parameters for the State of Sao Paulo, Brazil. Cadmium accumulation in leafy and root vegetables could be predicted by multiple regression analysis and most of the variance was explained when total Cd concentration and pH in soil were included as predictors. The calculated Cd bioconcentration factors (BCFs) for the tropical dataset were higher as compared to the temperate dataset. Consequently, critical soil Cd concentrations were from 1.7- to 3.2-fold lower for tropical conditions. Higher humidity and temperature at the tropics, as well as more weathered soils with lower retention capacity of Cd, may explain the higher Cd uptake and accumulation in tropical than in temperate regions. To protect human health, exclusive data regarding Cd in soils and edible vegetables from tropical regions should be used for the State of Sao Paulo to derive critical soil Cd concentrations, instead of (additional) data from temperate regions. [ABSTRACT FROM AUTHOR]

Prospects for wastewater irrigation in Brazil look promising, in light of the fact that agriculture plays an essential role in the country's economy and, furthermore, freshwater for irrigation is scarce in some parts of the country. However, irrigation with effluents still represents a new practice, and most available data related to the benefits and risks of effluent irrigation are based on short-term experiments. The present paper provides an overview of the potential of water reuse in Brazil; it describes the main results concerning effects of effluent irrigation on soil/plant interactions in Brazil, and discusses some important issues that require further investigation. So far, research in Brazil has been mainly focused on soil chemical changes that follow effluent application, while investigations concerning the occurrence and fate of trace contaminants, and the potential risks they present, remain to be carried out. Such contaminants include heavy metals and pharmaceutically active products. Effluent irrigation of agricultural crops intended for biofuel production represents a strategic issue, of increasing importance for the national and international market. For a consistent evaluation of long-term benefits and risks of effluent irrigation in this country, major needs are: improvement of the sewage collection and treatment infrastructure; establishment of legal regulations to control water reuse in agriculture; and permanent monitoring of areas already under wastewater irrigation. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Silvopastoral systems (SPS) have been suggested as an approach to reduce pasture degradation and, consequently, reduce the deforestation of new areas in the Brazilian cerrado (savanna). This study assessed the contribution of trees to soil fertility in a silvopastoral system in Lagoa Santa, Minas Gerais State, Brazil, 19° 35′ 36″ S, 43° 51′ 56″ W; altitude 747 m. The SPS has developed since 1984, through the use of natural regeneration of the native species Zeyheria tuberculosa Vell. Bur., with a density of 160 trees ha−1. The forage component of the system was Brachiaria brizantha cv. Marandu. The control treatment was a pasture adjacent to SPS with the same forage but without the influence of trees. In 2005, the litterfall of trees (leaves, fruits, and stems) was collected monthly, and the dry matter yield and nutrient content were measured. Soil profile samples were collected in February 2006. The litterfall of trees represented considerable inputs of nitrogen (N), potassium (K), and calcium (Ca2+). In the soil, organic matter (OM) and K reduced with depth. At this planting density, this tree species contributed mainly to amelioration of soil acidity, in the 0–2 cm layer and/or in the profile as a whole. In contrast, there were no significant differences in N, P, and K content of the control and SPS soil. This can be related to the high C/N and lignin/N ratios of the litter inputs. Agroforestry systems are complex and the site specific interactions among the components (tree, forage, and animal) must be understood to develop locally adapted systems and optimize productive efficiency. Consequently simple prescriptions for the implementation of SPS by land managers are unlikely. [ABSTRACT FROM AUTHOR]

The variability and the spatial dependence attributes of the following plant and soil: a) the soybean yield (SY) in no-tillage and irrigated, b) the macroporosity (MA), c) microporosity (MI), d) total porosity (TP), e) and bulk density (BD), in depths of 1 (0-0.10m), 2 (0.10-0.20m) and 3 (0.20-0.30 m), in a Red Latosol of the Engineering college of the São Paulo State University (FE/UNESP) in the Ilha Solteira campus, located in Selv&#x;ria County, Mato Grosso do Sul state, Brazil, were analyzed in the agricultural year of 2004/05. The main goal was to study the variability and the linear and spatial correlations among the attributes (plant and soil), aiming to select an index of soil physical quality with good capacity to represent the soybean yield. A geostatistical grid to collect soil and plant data was installed, with one hundred and twenty four sample points, in an area of 4000m². The linear relationship between soybean yield and physical attributes of soil studied was low. So, there was a direct spatial relationship between SY and MA1 (0-0.10m), as well as between SY and MA2 (0.10-0.20m). The MA1 showed its best index of the soil physical quality, when it was destined to estimate the soybean yield on no-tillage. [ABSTRACT FROM AUTHOR]

Abstract: Relief may be considered an integrating factor that expresses the interaction of various soil and plant attributes. This work aimed to analyze the potential use of landforms to predict the variability of soil and orange attributes. The study area is located in the state of São Paulo, Brazil. The following soil attributes were analyzed: clay content, organic matter content, water content, aggregate stability, macropores, micropores, total pore volume, saturated soil hydraulic conductivity, soil density, and soil resistance to penetration at 0.00–0.20-m depth. The orange attributes analyzed are total soluble solids, total titratable acidity, ratio, production, concentrated juice yield, and fruit size, which were performed in three periods (July, August and September). The soil and fruit data were submitted to descriptive statistical, geostatistical, and canonical correlation (CCA) analyses. The mean soil and fruit attributes were significantly different for the landforms by Tukey''s test at 5% probability. The analysis of the geostatistical results showed that the spatial variability of the soil and fruit attributes is influenced by landforms. We point out that the temporal variability of fruit attributes is also influenced by landforms, resulting in different ripening gradients for each of the relief compartments. The first canonical pair explained 77.00% of the attribute variance. The landforms were shown to be efficient in mapping the variability of the soil and orange attributes and contributed to the understanding of the soil–plant system. [Copyright &y& Elsevier]

The mango in the Brazilian semi-arid region stands out in the national scenario due to high yields and fruit quality, as well as to the possibility of all-year production due to climatic conditions and technologies which allow the management of plant growth and flowering through irrigation, pruning and use of plant growth regulators. Paclobutrazol applied to the soil is used for the production management of mangoes in most of the orchards. However, it is necessary to identify plant growth regulators which might be applied to the leaves, so as to minimize the risk of residues in the soil and to avoid inadequate application levels over several years. The present paper aimed at evaluating the effect of plant growth regulators applied to the leaves, regarding their efficiency for flowering management of mango 'Tommy Atkins'. Prohexadione-Ca, trinexapac-ethyl and chlormequat chloride at the dosage of 1.0 g a.i. plant-1 acts on the regulation of vegetative growth; the period of efficiency of the products applied to the leaves lasted 20 days for prohexadione-Ca, 30 days for chlormequat cloride, and 45 days for trinexapacethyl. [ABSTRACT FROM AUTHOR]

Sugar cane harvester performs five simple operations involving cutting of the stems in the base and in the top, feeding of the stems into the interior of the harvester, removing the leaves and cutting the stem in billets, which is optional. However, nowadays, there is a lack of processes to make these operations in an efficient way. The base cutter used in the conventional harvesters is made of double discs positioned in the inter row, however it is not adapted for the furrow planting system used in Brazil, and since it does not present capability of independent flotation for each disk, it causes the movement of a great amount of soil. This research project aimed to design, simulate, construct and evaluate in soil bin a four bar linkage suspension for a sugar cane base cutter to be used in a semimechanized harvesting system. The simulations allowed determining the suspension spring stiffness and its initial deformation in order to guarantee the flotation of the mechanism on the soil profile. The mechanism designed was built and mounted on a soil bin carriage for evaluation of the tracking performance of the base cutter when moving on a soil sine wave profile with amplitude of 25 and 50mm and 1.5m length. The results show that the mechanism accomplishes its objectives satisfactory with errors between 8 and 9mm for forward speeds of 0.14m s-1 and 0.42m s-1 respectively. [ABSTRACT FROM AUTHOR]