A physicochemical evaluation of ossein-hydroxyapatite within the bovine bone matrix revealed demineralization and making type I collagen available as a result of processing and solubilization by acids.

Bovine bone is an animal-origin matrix rich in type I collagen (COL I) and it necessitates prior demineralization and makes COL I available. This study investigated the ossein-hydroxyapatite physicochemical properties evaluation as a result of processing and solubilization by acids and revealed the bone matrix demineralization and making COL I available. The tibia residue from bovine sources was processed, ground, and transformed into bone matrix powder. The bone matrix was solubilized in acetic acid followed by lactic acid. The bone matrix was evaluated as a result of processing and solubilization by acids: ossein and hydroxyapatite percentages by nitrogen and ash content, mineral content, particle size distribution, Fourier-transformation infrared spectroscopy, x-ray diffraction, and scanning electron microscope. For the obtained residual extracts, pH and mineral content were evaluated. The solubilization by acids affected the ossein-hydroxyapatite physicochemical properties, and the bone matrix solubilized by acetic and lactic acid showed the preservation of the ossein alongside the loss of hydroxyapatite. The processing and the solubilization by acids were revealed to be a  alternative to bone matrix demineralization and enabling the accessibility of bone COL I. PRACTICAL APPLICATION: Bovine bone is an abundant type I collagen source, but processing maneuvers and demineralization effect present limitations due to the rigidity of the structural components. Exploring methodologies to process and demineralize will allow type I collagen to be obtained from the bone source, and direct and amplify the potentialities in the chemical and food industries. The research focused on bone sources and collagen availability holds paramount significance, and promotes repurposing agribusiness residues and development of protein-base products.

Combining biosolid and mineral sources of phosphorus and potassium in organomineral fertilizers influences the dynamics and efficiency of nutrient release.

Using urban residues to produce organomineral fertilizers (OMF) is an environmentally friendly strategy that can enhance soil fertility by adding organic matter and mineral nutrients. Herein we investigated the availability of N, P, and K, under organomineral fertilization in sandy soils. An incubation study was conducted using OMF formulated with biosolids as organic matrix and N source, rock phosphate, and potassium sulfate as P and K sources, respectively. Two forms of isolated N, P, and K sources (granulated and non-granulated), five N:P:K granulation proportions (1-2-0, 1-4-0, 1-0-2, 1-2-2, 1-2-4), and a control (unfertilized) were mixed with soil and assessed over a 112 days incubation period. Soil samples were collected at 0, 7, 14, 28, 56, and 112 days to quantify available soil concentrations of ammonium (N-NH4+), nitrate + nitrite (N-NO2- + N-NO3-), P, and K. The results showed that OMF formulated with NPK had better nitrogen efficiency indexes (NEI) than other formulations and did not induce N immobilization throughout the experiment. Regarding P and K efficiency, OMFs containing phosphorus and potassium increased the indexes compared to the single fertilizer sources. When comparing non-granulated potassium sulfate with granulated, the latter showed a steadier release due to the granulation process. In comparison with rock phosphate at the end of the experiment, the OMFs 1-2-0 and 1-4-2 had higher P available by 116 and 41%, respectively. Based on these results, OMFs have the potential to alter the dynamics of nutrient availability serving as a strategy for nutrient management in agriculture.

Oil well drill cuttings and sunflower cake: effects on sunflower crop and soil chemical attributes.

Onshore oil well drill cuttings and sunflower cake from biodiesel production require an appropriate destination to reduce the risks of environmental contamination. The aim of this study was to evaluate the potential use of the combination of different doses of these wastes on the growth of sunflower plants (Helianthus annus L.) and on soil chemical attributes after cultivation, making it possible to recommend safe application doses. Sunflower plants, cultivar Neon, were cultivated in a greenhouse for 80 days in Planossolo Háplico (Ultisol) as the main substrate. The design used was completely randomized, in a 6 × 6 factorial arrangement, composed of five doses of sunflower cake (2, 4, 8, 16 and 32 Mg ha-1) and five doses of drill cuttings (5, 15, 30, 45 and 60 Mg ha-1) and an experimental control using only Ultisol After cultivation, soil chemical attributes and the parameters height (H), stem diameter (D), and dry mass (DMAP) and nutrient contents in the aerial part of the plants were analyzed. Sunflower cake dose of 32 Mg ha-1 limited the germination of sunflower plants. In sunflower plants, the highest contents of calcium (Ca), magnesium (Mg), phosphorus (P) and potassium (K) were verified when the sunflower cake doses were associated with drill cuttings doses >45 Mg ha-1. The mixture between sunflower cake and drill cuttings in the proportion of 16:45 Mg ha-1, respectively, promoted higher H, D and DMAP of sunflower plants, as well as a considerable improvement in soil fertility, without causing significant increments in sodium content in the soil after cultivation.HighlightsInadequate disposal of agro-industrial wastes represents loss of raw material and energy.Drill cuttings and sunflower cake wastes enable improvements in soil fertility attributes.The combination of sunflower cake and drill cuttings contributed to sunflower growth and nutrient contents.The mixture of drill cuttings and sunflower cake has potential for use as agricultural input.

Effect of the application of vermicompost and millicompost humic acids about the soybean microbiome under water restriction conditions.

Humic substances (HSs) are constituent fractions of organic matter and are highly complex and biologically active. These substances include humic acids (HA), fulvic acids (FA), and humin. HS are known to stimulate the root system and plant growth and to mitigate stress damage, including hydric stress. Humic acids have already been reported to increase microbial growth, affecting their beneficial effect on plants. However, there is scarce information on whether HA from vermicompost and millicompost, along with Bradyrhizobium, improves the tolerance of soybean to water restriction. This study aimed to evaluate the responses of soybean plants to the application of vermicompost HA (HA-V) and millicompost (HA-M) along with Bradyrhizobium sp. under water restriction. The experiment was carried out in a greenhouse, and the treatments received Bradyrhizobium sp. inoculation with or without the application of HA from vermicompost and millicompost with or without water restriction. The results showed that HA provided greater soybean growth and nodulation than the control. The application of HA-M stimulated an increase in the richness of bacterial species in roots compared to the other treatments. After the application of water stress, the difference between the treatments disappeared. Microbial taxa were differentially abundant in plants, with the fungal fraction most affected by HA application in stressed roots. HA-V appears to be more prominent in inducing taxa under stress conditions. Although the results showed slight differences between HA from vermicompost and millicompost regarding plant growth, both humic acids promoted an increase in plant development compared to the control.

Influence of spatial variability of soil chemical attributes on the nutritional status and growth of the rubber tree

The productive potential of the rubber tree (Hevea brasiliensis) is dependent on its genetic composition, in addition to edaphoclimatic factors and management practices. However, as soil properties are not homogenous, knowing the spatial variability of soil attributes would be important to increase productivity and reduce production costs. In this context, the objective of this study was to determine the spatial variability of chemical attributes of the soil and its influence on the nutritional status and growth of rubber tree clones. Clones FX 3864, FDR 5788, CDC 312, and RRIM 600 were planted at Jaturnaíba Farm, in the municipality of Silva Jardim, Rio de Janeiro State, Brazil. The sampling sites were distributed at a spacing of 20 × 20 m on the northern and southern sides of the relief. The chemical attributes of the soil (pH, Ca2+, Mg2+, K+, P, Al3+, H+Al, sum of bases, cation exchange capacity, and base saturation) were evaluated at a depth of 0­20 cm in the different clone plantations. Additionally, the N, P, K, Ca, and Mg content as well as trunk circumference and total plant height, were also evaluated. Geostatistics was used to determine the spatial variability of the soil and clone attributes, while Ordinary Kriging was used to draw variability maps of the variables. A difference in the distribution of the variables, which was dependent on the slope of the relief, was detected through the maps. The southern side presented better conditions as some degradation was observed on the northern side. Certain soil characteristics influenced the distribution of the attributes of the planted clones; for example, the low concentration of Ca2+ in the soil caused Ca deficiency in the FX clone on the southern slope, indicating that liming did not supply enough nutrients for this clone. Our results showed that the variability in soil attributes influenced the nutritional status and growth of the rubber tree clones, indicating that variability maps can guide the planting and management of the rubber tree, providing more efficient management.

Epigeal fauna and soil attributes in a cover-cropped organic vegetable system / Fauna epígea e atributos do solo sob manejo com plantas de cobertura em cultivo orgânico

ABSTRACT: This study assessed the effect of cover crop biomass on the epigeal fauna of an organic eggplant (Solanum melongena L.) cropping system. A randomized block design was used, with four cover crop treatments: brachiaria, crotalaria, millet, and cocktail (brachiaria, crotalaria and millet). The epigeal faunal indices were determined at each plot. The epigeal fauna of a secondary forest site was also assessed for comparison. Epigeal individuals were collected using pitfall traps at two sampling periods (110 and 180 days after mowing cover crops). Soil samples were collected for determination of physical and chemic properties. 2032 individuals were captured in the first sampling and 3806 individuals in the second. The highest values of wealth in the first collection were observed in the millet and cocktail areas. Cluster analysis showed similarity of epigeal faunal groups between millet and brachiaria plots at the first sampling and between cocktail and crotalaria sites at the second sampling. Co-inertia analysis showed a significant covariance between epigeal fauna at the second sampling and soil properties. The cover crops management had a beneficial influence on the activity, wealth and ecological indexes, in both sampling periods. The positive association observed between epigeal faunal groups and soil physical and chemical properties demonstrates the efficiency of cover crops in improving soil quality in organic cropping systems.

RESUMO: O objetivo deste estudo foi avaliar o efeito da fitomassa de diferentes plantas de cobertura no desenvolvimento da comunidade da fauna epígea em área de cultivo orgânico de berinjela (Solanum melongena, L.). Foi adotado delineamento em blocos ao acaso, com quatro tratamentos de plantas de cobertura: braquiária, crotalária, milheto e coquetel (crotalária, braquiária e milheto), além de uma área de floresta secundária (FR). A fauna epígea avaliada por meio de armadilhas do tipo "pitfall traps" em dois períodos de coletas, aos 110 dias e aos 180 dias, após o corte das plantas de coberturas. Foram coletadas amostras de solo para análise de atributos físicos e químicos. Foram capturados 2032 indivíduos na primeira coleta e 3806 indivíduos na segunda coleta. Os maiores valores de riqueza na primeira coleta foram observados nas áreas milheto e coquetel. A análise de agrupamento mostrou similaridade dos grupos da fauna epígea entre o milheto e braquiária na primeira amostragem e entre o coquetel e crotalária na segunda amostragem. A co-inércia evidenciou covariância significativa entre a fauna epígea da segunda coleta e os atributos do solo. O manejo com plantas de coberturas influenciou de forma benéfica a atividade, riqueza e índices ecológicos, em ambos os períodos de amostragens. A associação positiva entre grupos da fauna e os atributos físicos e químicos mostram a eficiência das plantas de coberturas em cultivo orgânico na promoção de melhorias da qualidade do solo.

Fluoroquinolones and trace elements in poultry litter: estimation of environmental load based on nitrogen requirement for crops.

Poultry litter soil application contributes to sustainability of agricultural systems and is in accordance with the United Nations Sustainable Development Goals (UN-SDG). Poultry litter recommended rates are based on crop nitrogen (N) needs, however, their application can be a potential source of antibiotics and trace elements overload. The aim of the study was to estimate the role of poultry litter application on soil contamination by fluoroquinolones [enrofloxacin (ENR) and ciprofloxacin (CIP)] and trace elements, based on N requirements for crops. Analytical and sampling techniques were used to estimate the loads from poultry litter application. Only CIP was found in poultry litter samples (283 ± 124 µg kg-1) and its load was estimated to be of 9.89 ± 4.33 g ha-1, for the poultry litter application (35 t ha-1). The estimated loads (g ha-1) of trace elements were: Cr 9.19 ± 3.26, Ni 12.3 ± 4.93, Pb 22.0 ± 8.26, Cu 229 ± 85.6, Mn 691 ± 259 and Zn 1,011 ± 378. These estimates were 900% higher than those recommended by the technical guidance, while N exceeded 600% the recommended application. In order to achieve UN-SDGs, local policies to disseminate knowledge and technologies are required for consolidating sustainable agricultural practices.

Biochar amendment improves degraded pasturelands in Brazil: environmental and cost-benefit analysis.

Most deforested lands in Brazil are occupied by low-productivity cattle ranching. Brazil is the second biggest meat producer worldwide and is projected to increase its agricultural output more than any other country. Biochar has been shown to improve soil properties and agricultural productivity when added to degraded soils, but these effects are context-dependent. The impact of biochar, fertilizer and inoculant on the productivity of forage grasses in Brazil (Brachiaria spp. and Panicum spp.) was investigated from environmental and socio-economic perspectives. We showed a 27% average increase in Brachiaria production over two years but no significant effects of amendment on Panicum yield. Biochar addition also increased the contents of macronutrients, soil pH and CEC. Each hectare amended with biochar saved 91 tonnes of CO2eq through land sparing effect, 13 tonnes of CO2eq sequestered in the soil, equating to U$455 in carbon payments. The costs of biochar production for smallholder farmers, mostly because of labour cost, outweighed the potential benefits of its use. Biochar is 617% more expensive than common fertilizers. Biochar could improve productivity of degraded pasturelands in Brazil if investments in efficient biochar production techniques are used and biochar is subsidized by low emission incentive schemes.

Chemical attributes of soil and growth of castor beans fertilized with drilling gravel from oil wells and castor pie.

The extraction of oil from onshore wells and the production of biodiesel from castor bean crops have grown in recent years, resulting in the production of large volumes of drill cuttings from these wells and castor pie, which can be harmful to the environment. The objective of this work was to evaluate the influence of a combination of different doses of drill cuttings and castor pie on the chemical attributes of a Planosol and on the dry mass production of the aerial part (DMAP) and dry mass of roots (DMR) of castor bean crops (Ricinus communis L.), cultivar BRS-149 Nordestina. The experimental design was a randomized block with a factorial 6 × 6, consisting of five castor pie doses (2, 4, 8, 16, and 32 Mg ha-1); five drill cuttings doses (5, 15, 30, 45, and 60 Mg ha-1) and an experimental control using only soil samples, with three repetitions. The soil used as the main substrate was collected at 0.0-0.2 m depth in a Planosol. The mixture of the topsoil layer with the experimental doses was performed using a mixer for 5 min, and the samples were distributed in 8 dm3 pots; each pot corresponded to an experimental unit. The mixture of cuttings from drill wells and castor pie with a 30: 16 Mg ha-1 ratio, provided favorable chemical conditions for castor bean crop development; however, drill cuttings doses >30 Mg ha-1 can cause soil salinization, and negatively affect the development of castor bean crops.

Fluoroquinolones in agricultural soils: Multi-temporal variation and risks in Rio de Janeiro upland region.

Our main goal was to investigate the potential accumulation of fluoroquinolones (FQs) in agricultural soils over extended periods of land use, predicting leaching and estimating risk quotients for soil microorganisms. Short to long-term of poultry litter fertilization (<1-30 years) were evaluated for enrofloxacin (ENR) and ciprofloxacin (CIP) input, in addition to the emergence of plasmid-mediated quinolone resistance (PMQR) genes. High FQs concentration (range 0.56-100 mg kg-1) were measured in poultry litter samples. In soils, FQs occurrence and risks have changed over the years. An accumulation trend was observed between short and medium-term fertilized soils (ST and MT soils), reaching a range of 330-6138 µg kg-1 ENR and 170-960 µg kg-1 CIP in MT soil, followed by decreased concentrations in long-term fertilized soils (LT soils). The environmental risk assessment showed a high ENR risk quotient (RQ ≥ 1) in ST and MT soils ranging (7-226) and high CIP risk (9-53) in LT soils. The detection of qnrS genes in the area with the lowest FQs concentration emphasizes the importance of a broader approach to environmental assessment, in which not only target compounds are considered. FQs soil-water migration model pointed out a high leaching risk in ST soil. To reduce risks, management measures to decrease antibiotic environmental load should be taken before poultry litter application. In addition, the high weathering of tropical soils contributing to possible fate of antibiotics to water resources through drainage basins should be considered.

Multi-temporal accumulation and risk assessment of available heavy metals in poultry litter fertilized soils from Rio de Janeiro upland region.

Poultry litter is widely used as fertilizer in soils and can be a relevant source of heavy metals for agricultural environments. In this study, poultry litter fertilization of long-term (< 1-30 years) was evaluated in tropical soils. Our main goal was to investigate the occurrence of temporal variation in the available fraction of heavy metals (Cu, Cr, Zn, Pb, Cd, and Mn) in soils, in addition to their environmental loads through new indexes for risk assessment. The highest mean concentrations in poultry litter were the following: 525 mg kg-1 for Mn, 146 mg kg-1 for Zn, and 94.4 mg kg-1 for Cu. For soils, concentrations were higher for the same heavy metals: Mn (906 mg kg-1), Zn (111 mg kg-1), and Cu (26.3 mg kg-1). Significant accumulation (p < 0.05) in fertilized soils was observed for Cu, Cr, and Zn. The high estimates of poultry litter input based on geological background (LIGB) for Cu, Cr, and Zn coincided with the accumulation observed in soils, confirming the effectiveness of the index. The risk of biogeochemical transfer based on fertilized soils (LIFS) decreased for Cu, Cr, and Zn between 10 and 30 years of soil fertilization. For Mn, a very high LIFS was estimated in all long-term fertilized soils. The proposed indices, based on heavy metal concentration, can be used in risk assessments to guide future studies that analyze other environmental matrices possibly impacted by manure and poultry litter fertilization.

Urease activity according to the different inhibitors.

The objective of this study was to evaluate NBPT, zeolite and humic acid in different concentrations as inhibitors of the activity of the enzyme urease. The activity of the urease enzyme was quantified by the methods proposed by May and Douglas (1976) and Witte and Medina-Escobar (2001). For this reason, two experiments were conducted in a completely randomized design in split plots, in which the incubation periods are the plots and the fertilizers with the inhibitors at the different concentrations are the subplots with three replications. Fifteen fertilizers based on NBPT-coated urea, humic acid and zeolite were used in different concentrations. The two methods of analysis used in the experiment confirmed the efficiency of NBPT in inhibiting the enzymatic action even at low concentration, with 0.02% (m/m) being sufficient to inhibit urease, with no difference between inhibitor concentrations. The addition of humic acid reduced the activity of urease after 36 hours of reaction when the activity of the enzyme was evaluated by the method proposed by May and Douglas (1976). Zeolite did not influence the activity of the urease enzyme when analyzed by the May and Douglas method (1976).

Spatial variability and solubility of barium in a petroleum well-drilling waste disposal area.

The petroleum industry generates a range of wastes which is often are disposed in soil close to the well location, negatively affecting soil and water quality. The objective of this study was to evaluate the solubility and map the spatial variability of barium in a potentially contaminated area. The study area consisted of a petroleum well-drilling waste disposal site located in the municipality of Mato Rico-PR. A large georeferenced sampling grid was organized. Soil samples were collected at depths of 30, 60, 90, and 120 cm for determination of the "pseudo-total" concentrations and geochemical fractionation of barium. The barium concentrations showed spatial dependence, which permitted the use of geostatistical interpolators. Regarding depth, the depth of 0-30 cm showed the largest contaminated area; however, higher concentrations of barium were found at the depth of 60-90 cm. The results of geochemical fractionation showed that the analyzed samples contained percentages higher than 99% in the non-labile fraction (residual). These results indicate clearly that the barium was in a condition of low solubility, even for samples that had the highest concentrations, presenting low-environmental risk.

Quality reference values of trace elements in Brazilian organosols.

Determination of the natural background levels of trace elements in organosols and the proposal of quality reference values (QRVs) for these elements are essential for monitoring these soils because they are fragile and subject to change more intensely and rapidly than other soil classes. Given the above information, the objectives of this study were to determine the QRVs of trace elements for organosols and to correlate some soil properties with the occurrence of these elements. Forty organic soil horizon samples from different regions of Brazil were selected to determine the pseudo-total content of trace elements. The samples were separated into three groups according to a cluster analysis. The soil variable Fe and C contents had the strongest influence on the trace element contents in the organosols and were therefore used in the group classification functions. QRVs were proposed according to the 75th percentiles of the groups. The classification functions are a suitable tool for the allocation of new samples into previously established groups and may potentially be used to estimate the degree of organosol degradation.

Structure-Property-Function Relationship in Humic Substances to Explain the Biological Activity in Plants.

Knowledge of the structure-property-function relationship of humic substances (HSs) is key for understanding their role in soil. Despite progress, studies on this topic are still under discussion. We analyzed 37 humic fractions with respect to their isotopic composition, structural characteristics, and properties responsible for stimulating plant root parameters. We showed that regardless of the source of origin of the carbon (C3 or C4), soil-extracted HSs and humic acids (HAs) are structurally similar to each other. The more labile and functionalized HS fraction is responsible for root emission, whereas the more recalcitrant and less functionalized HA fraction is related to root growth. Labile structures promote root stimulation at lower concentrations, while recalcitrant structures require higher concentrations to promote a similar stimulus. These findings show that lability and recalcitrance, which are derived properties of humic fractions, are related to the type and intensity of their bioactivity. In summary, the comparison of humic fractions allowed a better understanding of the relationship between the source of origin of plant carbon and the structure, properties, and type and intensity of the bioactivity of HSs in plants. In this study, scientific concepts are unified and the basis for the agronomic use of HSs is established.

Vermicompost humic acids modulate the accumulation and metabolism of ROS in rice plants.

This work aims to determine the reactive oxygen species (ROS) accumulation, gene expression, anti-oxidant enzyme activity, and derived effects on membrane lipid peroxidation and certain stress markers (proline and malondialdehyde-MDA) in the roots of unstressed and PEG-stressed rice plants associated with vermicompost humic acid (VCHA) application. The results show that the application of VCHA to the roots of unstressed rice plants caused a slight but significant increase in root ROS accumulation and the gene expression and activity of the major anti-oxidant enzymes (superoxide dismutase and peroxidase). This action did not have negative effects on root development, and an increase in both root growth and root proliferation occurred. However, the root proline and MDA concentrations and the root permeability results indicate the development of a type of mild stress associated with VCHA application. When VCHA was applied to PEG-stressed plants, a clear alleviation of the inhibition in root development linked to PEG-mediated osmotic stress was observed. This was associated with a reduction in root ROS production and anti-oxidant enzymatic activity caused by osmotic stress. This alleviation of stress caused by VCHA was also reflected as a reduction in the PEG-mediated concentration of MDA in the root as well as root permeability. In summary, the beneficial action of VCHA on the root development of unstressed or PEG-stressed rice plants clearly involves the modulation of ROS accumulation in roots.

pH, sódio, potássio, cálcio, magnésio e alumínio em solos contaminados com fluido de perfuração de poços de petróleo após ensaios de lixiviação / pH, sodium, potassium, calcium, magnesium and aluminum in soils contaminated with petroleum drilling fluid after leaching tests

Na exploração do petróleo, o uso de fluidos de perfuração é essencial para o equilíbrio da pressão entre as formações e o interior do poço, além de impedir o refluxo do reservatório de petróleo ao poço. Os fluidos também são responsáveis pela elevação dos cascalhos de perfuração à superfície. Entretanto, estes podem ser potenciais contaminantes do ambiente, uma vez que chegam à superfície impregnados de fluidos. O trabalho objetivou avaliar o pH e os teores de Na+, K+, Ca2+, Mg2+e Al3+em um Latossolo e um Planossolo submetidos a doses de fluido de perfuração, após sofrerem dois ensaios de lixiviação. Os resultados mostraram que a adição dos fluidos ao Planossolo e Latossolo nas concentrações de 4%, 8% e 16% (m/m) reduziu o alumínio tóxico a zero e promoveu aumento do pH do solo, Na+, K+e Ca2+em comparação ao controle.

In petroleum exploration, the use of drilling fluids is critical to the balance of pressure between the formations and the interior of the shaft, and preventing the backflow of oil from the reservoir to the oill well. Fluids are also responsible for raising the drill cuttings to the surface. However, these may potentially contaminate the environment once they arrive at the fluid-impregnated surface. This study aimed to check the pH and Na+, K+, Ca2+, Mg2+ and Al3+ in an Oxisol and Planosol subjected to doses of drilling fluid, after suffering two leaching tests. The results showed that the addition of fluids to Planosoland Oxisol at concentrations of 4%, 8% and 16% (w / w) reduced toxic aluminum to zero and promoted an increase of the soil pH, Na+, K+ and Ca2+ compared to control.

Salinity Reduction and Biomass Accumulation in Hydroponic Growth of Purslane (Portulaca oleracea).

In many of the world's semi-arid and arid regions, the increase in demand for good quality water associated with the gradual and irreversible salinisation of the soil and water have raised the development of techniques that facilitate the safe use of brackish and saline waters for agronomic purposes. This study aimed to evaluate the salinity reduction of experimental saline solutions through the ions uptake capability of purslane (Portulaca oleracea), as well as its biomass accumulation. The hydroponic system used contained three different nutrient solutions composed of fixed concentrations of macro and micronutrients to which three different concentrations of sodium chloride had been added. Two conditions were tested, clipped and intact plants. It was observed that despite there being a notable removal of magnesium and elevated biomass accumulation, especially in the intact plants, purslane did not present the expected removal quantity of sodium and chloride. We confirmed that in the research conditions of the present study, purslane is a saline-tolerant species but accumulation of sodium and chloride was not shown as previously described in the literature.

Acúmulo de nutrientes e produtividade de crambe em função da fertilização com torta de mamona e serpentinito / Nutrient accumulation and productivity of crambe according to fertilization castor bean and serpentinite

O uso de fontes alternativas para a fertilização na agricultura vem sendo cada vez mais explorada pelo homem, devido à escassez das fontes finitas dos minerais utilizados atualmente. Produtos como a torta de mamona e silicatos de serpentinito podem ser fontes viáveis para o uso na agricultura. Com isso, o objetivo deste trabalho foi avaliar os teores e conteúdos de N, P, K, Ca e Mg na cultura do crambe, assim como a sua produção em função da adubação com torta de mamona PDS e silicato de serpentinito. O experimento foi conduzido em casa de vegetação em um delineamento inteiramente casualizado, com sete doses de torta de mamona PDS e duas doses de silicato de serpentinito (com e sem enxofre elementar), totalizando 21 tratamentos. Utilizaram-se as doses de 0,0; 0,5; 1; 2; 4; 6 e 8t ha-1 de torta de mamona PDS (equivalente à aplicação de 0, 15, 30, 60, 120 e 240kg ha-1 de N) e as doses de silicato de serpentinito em 0 e 1t ha-1, com e sem enxofre. A aplicação de silicato de serpentinito sem enxofre aumentou os teores e conteúdos de nutrientes de N, P, K, Ca e Mg do crambe e a produção de sementes. O uso de torta de mamona PDS como fertilizante orgânico favoreceu o crescimento e desenvolvimento do crambe. A dose de 8t ha-1 de torta de mamona PDS foi a mais indicada para a fertilização da cultura do crambe.

The use of alternative sources for fertilization in agriculture is being increasingly exploited by man because of the shortage of the finite sources of minerals used today. Products such as cake castor bean and serpentinite silicate, may be viable sources for use in agriculture. Thus, the aim of this study was to evaluate the contents and accumulation of N, P, K, Ca and Mg in the culture of crambe, as well as their production in line with fertilization cake castor bean PDS and silicate serpentinite. The experiment was conducted in a greenhouse in a completely randomized design with seven doses of cake castor bean PDS and two doses of serpentinite silicate (with and without elemental sulfur), totaling 21 treatments. We used doses of 0.0, 0.5, 1, 2, 4, 6 and 8t ha-1 of cake castor bean PDS (equivalent to the application of 0, 15, 30, 60, 120 and 240kg ha-1 of N) and the doses of serpentinite silicate 0 and 1t ha-1 for with and without sulfur. The application of serpentinite silicate without sulfur increased the content and nutrient content of N, P, K, Ca and Mg and crambe seed production. The use of cake castor bean PDS as organic fertilizer increased the growth and development of crambe. A dose of 8t ha-1 of castor bean PDS was the most suitable for the fertilization of the crop crambe.

The effects of oil well drill cuttings on soil and rice plant development (Oryza sativa) under two redox conditions.

Few studies have focused on the release of toxic elements from oil well drill cuttings and their effect on soil. The present study evaluated these effects using rice growth as the endpoint. Drill cuttings were collected from a Brazilian well and added in doses of 300, 3,000 and 6,000 mg kg(-1) soil, which was maintained at oxidized or reduced conditions. When the redox potential reached approximately -250 mV, barium concentrations were determined by geochemical fractionation. Overall, doses of 300 and 3,000 mg kg(-1) promoted plant development, while a dose of 6,000 mg kg(-1) inhibited it due to the associated increase in electrical conductivity and exchangeable sodium concentration. In addition, the lower redox potential promoted solubilization of barite from the drill cuttings, which increased barium absorption by plants and translocation to grain, posing a risk to human health.