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Revista Brasileira de Ciência do Solo, Volume: 43, Publicado: 2019
  • Genesis and Classification of Nitisols from Volcano-Sedimentary Lithology in Northeastern Brazil Division - Soil In Space And Time

    Costa, Edivan Uchôa Cavalcanti da; Araujo, Jane Kelly Silva; Neves, Laércio Vieira de Melo Wanderley; Araújo Filho, José Coelho de; Sousa, Juliet Emília Santos de; Corrêa, Marcelo Metri; Ribeiro Filho, Mateus Rosas; Souza Júnior, Valdomiro Severino de

    Resumo em Inglês:

    ABSTRACT On the southern coast of Pernambuco State (PE), Brazil, lithotypes of the Cabo Basin (volcanic and sedimentary rocks), in association with the relief, allow the determination of the dynamics of the formation of Nitossolos Háplicos (Nitisols), including those with high levels of exchangeable aluminum. The objective of this study was to evaluate the influence of lithological diversity (basalt and sedimentary siliciclastic rocks) on the morphological, physical, chemical, and mineralogical properties of Nitossolos Háplicos along a slope (P1-summit, P2-backslope, P3-footslope) on the southern coast of PE, in order to consider its genesis and the relation of soil properties to adjacent environments and to evaluate its framing within the Brazilian Soil Classification System (SiBCS). The interaction of lithology/soil permeability and climate indicate significant differences in the mineralogical composition and dynamics of soil chemical elements. The profiles P1 and P2 are subject to monosialitization, ferralitization, and alitization processes. All profiles showed high Fe contents (ferric soils) and clay fractions, consisting primarily of kaolinite, goethite, hematite, and gibbsite, as well as quartz and feldspar in the sand and silt fractions. However, smectite minerals (P3) are probably inherited from the sedimentary source material. In the conglomerate samples, under P3, biotite, muscovite, and plagioclase were identified. Allytic characteristics (P3) are probably associated with the weathering of aluminous smectite minerals. These properties distinguish these soils from adjacent Nitossolos and other Nitossolos in Brazil. For the classification of soils according to SiBCS, considering the high levels of Fe and Al, Nitossolo Háplico distroférrico (P1 and P2) and Nitossolo Háplico alitiférrico (P3) are suggested, and according to the World Reference Base of Soils (WRB), the soils are classified as Ferritic Nitisols.
  • Field Description and Identification of Diagnostic Qualifiers for Urban Soils in Brazil Division – Soil In Space And Time

    Costa, Jéssica Rafaela da; Pedron, Fabrício de Araújo; Dalmolin, Ricardo Simão Diniz; Schenato, Ricardo Bergamo

    Resumo em Inglês:

    ABSTRACT Human activities often alter soils found in urban areas. These alterations affect their environmental functions and potential for use. However, soils from urban areas in Brazil have not been surveyed and identified, which can pose a technical problem for the development of the city. Considering the importance of urban environments and their soils, this study aimed to evaluate the environmental and morphological characteristics and the physical properties of urban soils in Santa Maria, Rio Grande do Sul, Brazil. The purpose was then to organize a protocol for describing urban soils and to identify diagnostic qualifiers to subsidize establishment of an order that allows proper classification of these soils in the Brazilian Soil Classification System. The protocol containing general and environmental notes and morphological notes and qualifiers was organized based on the experience of this study and the relevant literature. The environmental, morphological, and physical analyses carried out supported interpretation of the urban soils of Santa Maria, their classification in the World Reference Base for Soil Resources system, and identification of diagnostic qualifiers proposed for the Brazilian Soil Classification System. The protocol tested in this study was adequate for data collection in the field. Soils had high variation in layer thickness, particle size composition, color, bulk density, saturated hydraulic conductivity, penetration resistance, stoniness, and the presence of artifacts. Considering the establishment of a Brazilian taxonomy for urban soils, the field data led to the proposal for new qualifiers, such as Saprolitic (residual saprolite material), Impervic (sealed/impermeable layer), Multigranic (layers with contrasting textures), Stonic (layers with stoniness), and Saprorockic (layers constituted of transported saprolite), which can be used as diagnostic attributes in the Brazilian Soil Classification System and even contribute to improvement of the order of Technosols in the World Reference Base For Soil Resources system.
  • Field Perception of the Boundary Between Soil and Saprolite by Pedologists and its Differentiation Using Mathematical Models Division – Soil In Space And Time

    Santos, Roseclênia Alves; Sermarini, Renata Alcarde; Guerra, Adriano Ribeiro; Santos, Jean Cheyson Barros dos; Azevedo, Antonio Carlos de

    Resumo em Inglês:

    ABSTRACT Saprolite plays a central role into hydrologic and nutrient cycles. Despite that, saprolite research is scattered and uses heterogeneous, sometimes conflicting, methods and concepts. During field work, it is difficult to assign the boundary between soil and saprolite. This paper aimed to identify the subjacent logic that pedologists use to assign to a regolith volume its soil or saprolite nature. To achieve this goal, a tree algorithm was used to build a hierarchy of physical and chemical properties of a set of regolith profiles. Such hierarchization expose the inner, subjective criteria used by researchers during the assignment of a certain profile zone as saprolite or soil. The following variables were measured: total porosity (TP); bulk density (Bd); particle density (Pd); total Fe2O3, Al2O3, CaO, MgO, K2O, Na2O, P2O5, and TiO2; selective extraction of iron by ditionite-citrate-bicarbonate (FeDCB) and ammonium oxalate (FeOA); and the FeDCB/FeOA ratio. These measurements were done in a set of 25 regolith profiles (137 horizons and layers), located in the Southeast region and Northeast region of Brazil. The decision tree algorithm was applied using the recursive partition method to identify which of the measured property was most strongly associated with the field assignment of the pedologists to a certain profile zone as saprolite or soil. The Bd, FeDCB/FeOA, MgO, CaO, TP, and P2O5 explained 93 % of the pedologists choice, being Bd responsible for 81 %.
  • AlradSpectra: a Quantification Tool for Soil Properties Using Spectroscopic Data in R Division - Soil In Space And Time

    Dotto, André Carnieletto; Dalmolin, Ricardo Simão Diniz; Caten, Alexandre ten; Gris, Diego José; Ruiz, Luis Fernando Chimelo

    Resumo em Inglês:

    ABSTRACT Soil reflectance spectroscopy has become an innovative method for soil property quantification supplying data for studies in soil fertility, soil classification, digital soil mapping, while reducing laboratory time and applying a clean technology. This paper describes the implementation of a Graphical User Interface (GUI) using R named AlradSpectra. It contains several tools to process spectroscopic data and generate models to predict soil properties. The GUI was developed to accomplish tasks such as perform a large range of spectral preprocessing techniques, implement several multivariate calibration methods, generate statistics assessment and graphical output, validate the models using independent dataset, and predict unknown variables using soil spectral data. AlradSpectra has four main modules: Import Data, Spectral Preprocessing, Modeling, and Prediction. The implementation of AlradSpectra is demonstrated by applying visible near-infrared reflectance spectroscopy for soil organic carbon (SOC) prediction. The data contains the value of SOC and Vis-NIR reflectance for 595 soil samples. The prediction statistic assessment of SOC was performed applying all spectral preprocessing and methods. The R 2 considering all models ranged from 0.54 to 0.80. In the partial least squares regression (PLSR) models, the performances were similar to multiple linear regression (MLR) and support vector machines (SVM). The lowest error in the SOC prediction was achieved by PLSR method with standard normal variate (SNV) preprocessing reaching an R 2 of 0.80, the smallest root mean square error (RMSE) of 0.47 %, and ratio of performance to inter-quartile distance (RPIQ) of 3.12. The capacity of performing multiple tasks, being free and open-source, easy to operate, and requiring no initial knowledge of R programming language are features that make AlradSpectra a useful tool to perform different modeling approaches and predict the desired soil variable.
  • A Regional Legacy Soil Dataset for Prediction of Sand and Clay Content with Vis-Nir-Swir, in Southern Brazil Division – Soil In Space And Time

    Silva, Elisângela Benedet; Giasson, Élvio; Dotto, André Carnieletto; Caten, Alexandre ten; Demattê, José Alexandre Melo; Bacic, Ivan Luiz Zilli; Veiga, Milton da

    Resumo em Inglês:

    ABSTRACT The success of soil prediction by VIS-NIR-SWIR spectroscopy has led to considerable investment in large soil spectral libraries. The aims of this study were 1) to develop a soil VIS-NIR-SWIR spectroscopy approach using legacy soil samples to improve spectral soil information in a regional scale; (2) to compare six spectral preprocessing techniques; and (3) to compare the performance of linear and non-linear multivariate models for prediction of sand and clay content. A total of 1,534 legacy soil samples, stored by Epagri, were collected from agricultural areas in 2009 on a regional scale, covering 260 municipalities of Santa Catarina. Six spectral preprocessing techniques were applied and compared with reflectance spectra (control treatment) in the development of sand and clay prediction models. Five multivariate regression models, Support Vector Machines, Gaussian Process Regression, Cubist, Random Forest, and Partial Least Square Regression were compared. The scatter-corrective preprocessing groups produced similar or better performance than spectral-derivatives. In addition, preprocessing spectra prior to regression analysis does not improve sand prediction, since reflectance spectra achieved the best performance using Cubist, SVM, and PLS models. In general, clay content presented better prediction accuracy than sand content. The best multivariate model to predict sand and clay content from soil VIS-NIR-SWIR spectra was Cubist. The best Cubist performance was achieved combined with reflectance spectra (R2 = 0.73; root mean square error = 10.60 %; ratio of the performance to the interquartile range = 2.36) and MSC (R2 = 0.83; root mean square error = 7.29 %; ratio of the performance to the interquartile range = 3.70) for sand and clay content, respectively. Considering the mean RMSE values of the validation set, the predictive ability of the multivariate models decreased in the following order: Cubist>PLS>RF>GPR>SVM for both properties. The predictive ability of VIS-NIR-SWIR reflectance spectroscopy achieved in this study for sand and clay content using legacy soil data and heterogeneous samples confirmed the potential of the spectroscopy approach.
  • Value of Functionalized Charcoal for Increasing the Efficiency of Urea N Uptake: Insights into the Functionalization Process and the Physicochemical Characteristics of Charcoal Division – Soil In Space And Time

    Paiva, Diogo Mendes de; Guimarães, Gelton Geraldo Fernandes; Teixeira, Breno Cardoso; Cantarutti, Reinaldo Bertola

    Resumo em Inglês:

    ABSTRACT Functionalized charcoal (CHox) incorporated into urea is known for its ability to reduce NH3 volatilization and increase agronomic efficiency. However, it is important to optimize the functionalization process and to elucidate its relationship with the physicochemical properties of CHox for N supply. Thus, charcoal obtained from eucalyptus wood was functionalized with different HNO3 concentrations and reaction times. Ammonia adsorption by CHox was evaluated in chambers with high NH3 concentrations. Dry matter yield, N uptake, and apparent N recovery efficiency of corn plants were evaluated after the application of the urea-CHox mixture to soil in a greenhouse experiment. The properties of CHox, such as pH, isoelectric point, and total acidity (carboxylic and phenolics groups) depended on the HNO3 concentration but were not influenced by the reaction time. The NH3 adsorption by the functionalized charcoal showed a positive correlation with the quantity of carboxylic and phenolic groups and a negative correlation with the pH value and the isoelectric point. The small differences observed in dry matter yield, N accumulation, and apparent N recovery efficiency among the corn plants from urea mixed with CHox or humic acids derived from charcoal (AHCH) are not sufficient to determine the higher efficiency of these sources.
  • Relief Position and Soil Properties under Continuous Banana Cropping in Subhumid Climate in Northeast Brazil Division – Soil In Space And Time

    Almeida, Maria da Conceição de; Araujo, Jane Kelly Silva; Ribeiro Filho, Mateus Rosas; Souza Júnior, Valdomiro Severino de

    Resumo em Inglês:

    ABSTRACT Sequences of thick and eroded soils in hills surfaces are cultivated with banana since the beginning of the last century in the Northeast of Pernambuco (PE), Brazil. Measurements of soil properties depending on soil slope under intensive agricultural cultivation are limited mostly as the pedogenetic approach. This study aimed to identify the dominant soil types, to evaluate morphological, physical, chemical, and mineralogical properties of soil profiles, and link them to the relief position under continuous banana cropping, in the transition Mata-Agreste of PE. Three slope classes and soil profiles were considered: Profile 1 (P1), upper third of the elevation slope; Profile 2 (P2), middle third of the slope; and Profile 3 (P3) lower third. They were opened, described, and soil samples collected from all horizons at a typical slope of the region. Independent of relief position and land use, all soils are deep (>1.50 m) and present the argic horizons (Bt) developed in all steeply sloping surfaces (15-33 %). The Bt horizon presented the highest values of soil bulk density and microporosity. Despite the presence of illite, all the soil profiles showed remarkable degree weathering, are mostly kaolinitic, besides presenting goethite and quartz in the soil clay fraction, and predominance of quartz in the silt and sand fraction. Water-stable aggregates >2 mm were dominant in all the relief positions. Acidity, low cation exchange capacity, and in general, nutrient poverty were observed in the soil profiles, as opposed accumulation of exchangeable cations on the lower third of the slope (P3). However, the soil properties were affected by land use and water erosion. The Ap horizons showed the highest values of pH, exchangeable bases, phosphorus available, and organic carbon due to agricultural practices, while the steepest slope (P2) had the lowest content of clay, phosphorus and mean weight diameter of aggregates, and higher organic carbon content, in the superficial horizon, due to removal and deposition by water erosion. From the upper third to the lower third of the slope, Nitic Acrisol, Haplic Acrisol, and Nitic Lixisol were formed.
  • Micromorphology and Genesis of Soils from Topolitosequences in the Brazilian Central Plateau Division – Soil In Space And Time

    Rolim Neto, Fernando Cartaxo; Schaefer, Carlos Ernesto Gonçalves Reynaud; Camêlo, Danilo de Lima; Corrêa, Marcelo Metri; Parahyba, Roberto da Boa Viagem; Caldas, Anildo Monteiro; Ibraimo, Anifo Soares Mamudo

    Resumo em Inglês:

    ABSTRACT The micromorphology of deeply weathered soils (Ferralsols/ Latossolos ) from the Central Plateau of Brazil remains little studied, and its affiliation to different parent materials, poorly known. To clarify the processes of soil formation of these acric, gibbsitic, Fe-oxide rich Ferralsols, three lithotoposequences on local ultrabasic to basic intrusive rocks were studied. The influences of mixing and pedobioturbation are evident in all soils, and Ferralsols of the Central Plateau of Brazil are polygenetic, based on the coarse mineral composition, with ultrabasic and metapelitic rock contributions. The typical oxic microstructure with stable microaggregates encompasses a gibbsite/Fe rich micromass with random inclusions of charcoal, allochthonous quartz, Ti-magnetite, and perovskite grains. Shallow Cambisols ( Cambissolos ) on tuffites also display a similar “oxic” microstructure, but a much lower degree of weathering. These Cambisols possesses apatite, and mafic and pelitic minerals as residuals minerals grains, indicating the polygenetic colluvia mixture of different substrates. The common occurrence of perovskite (CaTiO3) as a residual grain in deep-weathered, acric Ferralsols on ultrabasic rocks, not yet reported in the literature, shows an unusual resistant Ca reserve in oxic soils, though nothing is known about its implications to soil fertility.
  • Growth, Biomass and Carbon Stocks in Forest Cover Planted in an Area of Bauxite Mining in Rehabilitation Division – Soil Use And Management

    Valente, Fernanda Daniele de Almeida; Castro, Marllon Fialho de; Torres, Carlos Moreira Miquelino Eleto; Neves, Júlio César Lima; Silva, Ivo Ribeiro; Oliveira, Teógenes Senna

    Resumo em Inglês:

    ABSTRACT Forest cover in areas degraded by mining is an alternative way of mitigating CO2 concentrations in the atmosphere by fixing C in tree biomass. This study evaluated the growth and C stocks of forest cover in an area of bauxite mining with four sources of fertilizer. Height (Ht), diameter at ground level (DGL), and diameter at breast height (DBH) were determined in Anadenanthera peregrina (Ap), clonal Eucalyptus (Euc), and a mixed plantation of 16 native forest species (Nat) at 6, 18, 36, and 56 months of age. Trunk+bark volume, biomass, and C stock were also determined for these forest covers at 56 months of age. The fertilization treatments were a standard (SF) adopted by the company, SF plus organic fertilizer (OF), chemical fertilizer (CF), and OF+CF. Euc displayed greater values of Ht, DGL, and DBH under OF+CF and OF. Fertilization did not influence the Ht and DBH of Ap, but DGL was higher under OF+CF at 36 months compared to SF. The Ht values of Nat were influenced by fertilization at 18 months, with the lowest values under SF. The fertilization influenced the DGL of Nat at 36 and 56 months, which did not occur with DBH. The pioneer species had higher Ht, DGL, and DGB compared to non-pioneer species, regardless of the type of fertilization studied. Fertilization influenced the Ht and DGL of pioneer species at 18 and 36 months of age and only the Ht of non-pioneer species. The estimates of Euc biomass (255 Mg ha-1) and C stocks (120 Mg ha-1) under OF+OC were four times greater than in Ap and Nat, which showed no difference between themselves or the types of fertilization. The growth and estimates of volume, biomass, and C stocks of the forest cover were comparable to those of unmined areas. Euc had the greatest growth, biomass, and C stocks.
  • Effects of Simulated Nitrogen Deposition and Precipitation Manipulation on Soil Microorganisms in the Desert Steppe of Northern China Division – Soil Processes And Properties

    Meiqing, Jia; Jing, Huang; Yinghua, Yang; Guodong, Han; Guogang, Zhang

    Resumo em Inglês:

    ABSTRACT: Soil microorganisms are influenced by climate change. However, the effect of climate change on soil cultivable bacteria are unclear. In this study, the composition and diversity of the soil cultivable bacterial community were explored by a dilution–plate method, PCR, and 16S rRNA sequencing in a desert steppe of northern China after repeated NH4NO3 amendments and precipitation manipulation for seven years. The experimental treatments were as follows: control (CK), N addition (+N), N addition plus water addition (+N+W), and N addition plus water reduction (+N-W). Among the treatment groups, 11 genera and 17 bacterial species were isolated. Nitrogen addition and precipitation manipulation significantly increased the number of cultivable bacteria in the 0.00-0.30 m layer compared to CK. Compared to +N treatment, the +N+W and +N–W treatments had no significant impact on the number of cultivable bacteria. Compared to the CK community, bacterial communities exposed to the other three treatments did not show shifts in the relative abundance of dominant genera and other cultivable bacteria, except for Pontibacter and Staphylococcus. The treatments +N+W and +N-W significantly modified the relative abundance of Pontibacter and Staphylococcus compared to the +N treatment. Available potassium and phosphorus, and moisture content contributed to the change in the composition of the cultivable bacterial community (p>0.05). Nitrogen addition and precipitation manipulation significantly decreased species richness in the 0.00-0.02 m layer, but they did not affect evenness and the Shannon-Wiener Index in the 0.00-0.30 m layer. This study provides insights into how the composition and diversity of the bacterial community is affected by climate change scenarios.
  • Do Aggregate Size Classes of the Subsurface Soil Horizon Have Different Chemical/Mineralogical Properties? Division - Soil Processes And Properties

    Mitton, Rolff Vladimir; Melo, Vander Freitas; Pauletti, Volnei

    Resumo em Inglês:

    ABSTRACT Variations in chemical and mineralogical properties of a soil can occur at short vertical and horizontal distances. The objective of the present study was to evaluate the chemical and mineralogical soil properties of different aggregate classes from young (Ustrochrept) and highly weathered (Acrustox) soils from the state of Paraná, Brazil. Undisturbed blocks (0.20 ×0.20 ×0.20 m) of soils were separated into aggregate classes: Acrustox – 8.0-4.0 mm; 4-2 mm; 2.0-0.5 mm; 0.5-0.2 mm; and <0.2 mm; and Ustrochrept – 8.0-4.0 mm; 4.0-2.0 mm; 2.0-0.5 mm; and 0.5-0.2 mm. The exchangeable K contents showed an opposite behavior for the two soils: higher contents in the Acrustox for the larger aggregate classes and higher contents in the Ustrochrept for the smaller aggregate classes. The crystallographic characteristics of hematite and goethite were variable according to the aggregate class. The goethite in the 2-4-mm aggregate class is expected to exhibit the highest reactivity for the Ustrochrept: lower growth and a more elongated form of the crystals. The smallest aggregate class presented the lowest contents of kaolinite and gibbsite in the clay fraction. Gibbsite and kaolinite in the intermediate classes presented higher growth in both soils. The studied soils present different side-by-side environments (aggregate classes) for the exploration by the root system. This means that for the precise identification of the environments explored by the roots of a single plant, field sampling should consider the aggregate class, obtained from an undisturbed soil sample. However, this is impractical in agricultural practice.
  • Influence of ZnO Nanoparticles and a Non-Nano ZnO on Survival and Reproduction of Earthworm and Springtail in Tropical Natural Soil Division – Soil Processes And Properties

    Alves, Micheli Lucia; Oliveira Filho, Luís Carlos Iuñes de; Nogueira, Patrícia; Ogliari, André Junior; Fiori, Márcio Antônio; Baretta, Dilmar; Baretta, Carolina Riviera Duarte Maluche

    Resumo em Inglês:

    ABSTRACT: In recent years, various studies and development using nanoparticles (NPs) have been carried out in the most diverse areas of knowledge. Although nanomaterials are widely employed by many sectors and some may have a fertilizing potential, little is known about their effects on the environment. This study aimed to evaluate the effect of applying, in tropical natural soil, different contents of nanoparticles of zinc oxide (NPs-ZnO) and non-nano zinc oxide (ZnO) on soil pH and on the survival and reproduction rates of earthworms ( Eisenia andrei ) and springtails ( Folsomia candida ) through standardized ecotoxicological tests. The tests used a tropical soil representative of Brazil, classified as Entisol ( Neossolo Quartzarênico órtico típico ) with no history of agricultural use, collected in the 0.00-0.20 m layer, previously sieved (2-mm mesh) and defaunated. The experimental design was completely randomized, and treatments consisted of two forms of zinc (Zn), NPs-ZnO and ZnO, at the following doses: 0, 50, 100, 200, 400, 800, 2,000, and 4,000 mg kg−1. Standardized ecotoxicological tests showed no toxicity of NPs-ZnO in terms of lethality of E. andrei and F. candida . In E. andrei reproduction tests, NPs-ZnO were toxic at doses higher than 400 mg kg−1 (EC50 of 1,021 mg kg−1). Tests with F. candida demonstrated that its reproduction rate was significantly affected by NPs-ZnO at a rate of 4,000 mg kg−1 (EC50 of 3,636 mg kg−1). When used in Entisol, the NPs-ZnO inhibit the reproduction of earthworms and springtails; earthworms are more sensitive to such an effect, it being demonstrate at lower contents than those found for springtails.
  • Humic Substances and Chemical Properties of an Acrisol Amended with Vermicomposted Vegetal and Animal Residues Division – Soil Processes And Properties

    Antunes, Rul Martins; Leal, Otávio dos Anjos; Castilhos, Rosa Maria Vargas; Castilhos, Danilo Dufech; Andreazza, Robson; Schwalbert, Raí Augusto

    Resumo em Inglês:

    ABSTRACT Vermicomposted vegetal and animal residues are rich in nutrients and humic substances and thus can be applied to the soil as a source of functionalized organic matter (OM) and as an alternative to chemical fertilizers. In Southern Brazil, many animal and vegetal residues are easily accessible. Therefore, this study aimed to evaluate alterations in soil chemical properties and OM chemical composition in response to the application of local vermicomposted residues. The vermicomposts of: cattle manure (CM), sheep manure (SM), rice parboiling sludge (PS), CM+PS; SM+PS; CM+food waste (FW); SM+FW; CM+fruit waste (FRW); and SM+FRW were mixed with Acrisol (Argissolo) samples collected at 0.00-0.20 m layer, and the samples were incubated in plastic bags for 182 days. Soil samples without vermicomposts were also incubated (control). Overall, vermicomposts increased soil pH(H2O), exchangeable Ca and available P and K contents. The treatments with CM or SM with FW promoted carbon accumulation in the soil compared to the control, especially as humin. The humic acids of SM and PS were more oxygenated than the others, and oxygenation was apparently associated with aromatic structures. Fulvic acids of CM+PS showed the greatest oxygenation and aliphatic character. The relationship between vermicompost origin (animal or vegetal) and soil properties or OM composition was not clear. Aromaticity degree (H/C) and C/N ratio were similar in fulvic and humic acids, and oxygenation degree (O/C) as well as polarity index [(O+N)/C] were more efficient parameters to distinguish these humic fractions. We concluded that vermicomposts derived from cheap and easily available vegetal and animal residues in Southern Brazil have great potential as alternative fertilizers as well as sources of functionalized OM when applied to the soil, especially vermicomposts of rice parboiling sludge and cattle or sheep manure mixed with food waste.
  • Biochemical and Biological Properties of Soil from Murundus Wetlands Converted into Agricultural Systems Division – Soil Processes And Properties

    Martins, Luciene Nunes Barcelos; Santiago, Flávia Louzeiro de Aguiar; Montecchia, Marcela Susana; Correa, Olga Susana; Saggin Junior, Orivaldo José; Souza, Edicarlos Damacena de; Paulino, Helder Barbosa; Carneiro, Marco Aurelio Carbone

    Resumo em Inglês:

    ABSTRACT The implementation of conservationist systems that improve soil properties and reduce the impacts of the conversion of native areas is fundamental for feasible agricultural exploitation. This study aimed to evaluate the impact on soil biological properties caused by the conversion of murundus fields into agricultural systems and verify the ability of the no-tillage conservation system to recover these properties over the years. Treatments consisted of three agricultural areas subjected to the same management (no-tillage), in a chronosequence (7, 11, and 14 years of conversion) and a reference area (murundus field). To evaluate soil quality, we analyzed total soil organic carbon, microbial biomass carbon, soil basal respiration, metabolic and microbial quotients, and acid phosphatase activities, as well as the potential functionality of soil bacterial communities and the modifications in their genetic structure. The conversion of murundus field into agricultural systems negatively impacted soil biological properties, with expressive reduction in soil organic carbon content and microbial biomass carbon. The periods of adoption of the conservationist system (no-tillage) were not enough to recover the biological properties and/or to reverse the changes observed in the genetic structure of the soil bacterial communities of the managed areas, although stabilization trends were observed in the agricultural systems over the years.
  • Stability of Soil Moisture Patterns Retrieved at Different Temporal Resolutions in a Tropical Watershed Division – Soil Processes And Properties

    Barbosa, Luís Romero; Lira, Nicholas Borges de; Coelho, Victor Hugo Rabelo; Silans, Alain Marie Bernard Passerat de; Gadêlha, André Nóbrega; Almeida, Cristiano das Neves

    Resumo em Inglês:

    ABSTRACT Above and underground hydrological processes depend on soil moisture (SM) variability, driven by different environmental factors that seldom are well-monitored, leading to a misunderstanding of soil water temporal patterns. This study investigated the stability of the SM temporal dynamics to different monitoring temporal resolutions around the border between two soil types in a tropical watershed. Four locations were instrumented in a small-scale watershed (5.84 km2) within the tropical coast of Northeast Brazil, encompassing different soil types ( Espodossolo Humilúvico or Carbic Podzol, and Argissolo Vermelho-Amarelo or Haplic Acrisol), land covers (Atlantic Forest, bush vegetation, and grassland) and topographies (flat and moderate slope). The SM was monitored at a temporal resolution of one hour along the 2013-2014 hydrological year and then resampled a resolutions of 6 h, 12 h, 1 day, 2 days, 4 days, 7 days, and 15 days. Descriptive statistics, temporal variability, time-stability ranking, and hierarchical clustering revealed uneven associations among SM time components. The results show that the time-invariant component ruled SM temporal variability over the time-varying parcel, either at high or low temporal resolutions. Time-steps longer than 2 days affected the mean statistical metrics of the SM time-variant parcel. Additionally, SM at downstream and upstream sites behaved differently, suggesting that the temporal mean was regulated by steady soil properties (slope, restrictive layer, and soil texture), whereas their temporal anomalies were driven by climate (rainfall) and hydrogeological (groundwater level) factors. Therefore, it is concluded that around the border between tropical soil types, the distinct behaviour of time-variant and time-invariant components of SM time series reflects different combinations of their soil properties.
  • Comparison of the Casagrande and Fall Cone Methods for Liquid Limit Determinations in Different Clay Soils Division - Soil Processes And Properties

    Crevelin, Letícia Garcia; Bicalho, Kátia Vanessa

    Resumo em Inglês:

    ABSTRACT The liquid limit (LL) is an important parameter for soil classification systems. The use of the cone penetrometer technique for measuring the liquid limit is an attractive alternative method since the percussion method is highly operator dependent. In this article, the importance of specifying the procedure and equipment used to determine the LL of a clay soil is highlighted using LL test results conducted on different clay soils. The results of LL, obtained by the percussion method proposed by Casagrande (LLc) and by the penetration cone method (LLp) on clay soils of different geological origins and plasticity were compared. The LLp values were determined using the British cone (20 mm fall cone penetration) method. The LLc values were determined using different hardnesses of Casagrande apparatus. The LL test results show that variations on the investigated methods depend on the mineralogy of the clay soil and the hardness base of the Casagrande cup. The data obtained for kaolinites and illites minerals or low LL soils yielded LLp>LLc. The results obtained for smectite minerals or soils with high LL values indicated LLp<LLc and a greater dispersion among the results. Statistical analyses of residues show that empirical LLp-LLc correlations through a linear regression analysis should be used with caution.
  • Performance of the Groenevelt and Grant Model for Fitting Soil Water Retention Data from Brazilian Soils Division – Soil Processes And Properties

    Armindo, Robson André; van Lier, Quirijn de Jong; Turek, Maria Eliza; Reis, Aline Mari Huf dos; Melo, Marina Luciana Abreu de; Ramos, Maria Elisa Palma; Ono, Gabriela Massame

    Resumo em Inglês:

    ABSTRACT The soil water retention curve (SWRC) is essential for vadose zone hydrological modeling and related applications. In 2004, Groenevelt and Grant (GRT) presented a mathematical model for describing the SWRC and reported its mathematical versatility and good fit to soils from a Dutch database. In order to evaluate the application of GRT to SWRCs of Brazilian soils, we aimed to analyze the performance of GRT for 72 soils from Brazil. Besides that, the obtained results with GRT for these soils were compared to the fitting performance of the most frequently used models: Brooks and Corey (BC) and van Genuchten-Mualem (VGM). The three models were fitted to available soil water retention data by minimizing the sum of square errors. The Pearson correlation coefficient (r) and the Root Mean Square Error (RMSE) were used to assess the goodness-of-fit. Results showed high correlation coefficients (r≥0.95) and small values of RMSE (RMSE ≤0.03 cm3 cm-3) for all fits. The goodness-of-fit was of similar performance for the three models with a positively correlation between them. The major difference in shape among GRT, BC, and VGM occurred in the near saturated range, while they were almost identical for low matric potentials. The exponent of GRT showed to be highly correlated with exponents of BC and VGM, but the correlation between the other shape parameters is not well defined, making a direct conversion still difficult.
  • Hydrostatic Equilibrium between Soil Samples and Pressure Plates Used in Soil Water Retention Determination: Consequences of a Questionable Assumption Division - Soil Processes And Properties

    van Lier, Quirijn de Jong; Pinheiro, Everton Alves Rodrigues; Inforsato, Leonardo

    Resumo em Inglês:

    ABSTRACT Soil water retention is among the soil hydraulic properties most routinely measured in studies of soil physics and related areas. This property is used in dynamic simulations of vadose zone processes such as soil water availability, surface boundary processes of evaporation and infiltration, and the fate of soil pollutants. The most common measurement technique consists in establishing a hydrostatic equilibrium between an initially saturated soil sample and a porous medium at a certain tension on a tension table or pressure plate. However, there is reasonable doubt about the assumed hydrostatic equilibrium, especially in the dry range at low pressure heads. In this study we compared the traditional pressure plate apparatus protocol to an inverse parameter estimation protocol based on a transient evaporation experiment. Independent pressure head measurements using a dewpoint device were also performed. We sampled a variety of soil textures typical of the Brazilian subtropical humid zones, aiming to show differences between textures in their subjection to hydraulic nonequilibrium. The performed experiments allow to conclude that the two compared protocols showed real pressure heads in samples on a pressure plate to be less negative than the assumed ones, leading to an overestimation of the soil water content in the dry range at low pressure heads, especially in fine-textured soil samples. This affects the reliability of most soil hydraulic databases, derived PTFs in the dry range, as well as the wilting point estimation. Water availability predictions based on total and readily available water are more sensitive to the water retention measurement method when the chosen lower limits of available water are closer to the wilting point. In this sense, irrigation timing criteria based on readily available water should be preferred over total available water, especially for fine-textured soils. Finally, given the low reliability of the pressure plate apparatus for low pressure heads, possibly biasing hydrological simulations and their interpretation, alternative measurement methods for the drier part of the soil water retention curve should be preferred, e.g., the proposed inverse modeling of evaporation experiments.
  • Effect of Inoculation of Pineapple Plantlets with Arbuscular Mycorrhizal Fungi Obtained from Different Inoculum Sources Multiplied by the On-Farm Method Division – Soil Processes And Properties

    Moreira, Bruno Coutinho; Prates Junior, Paulo; Jordão, Thuany Cerqueira; Silva, Marliane de Cássia Soares da; Ribeiro, Ana Paula Ferreira; Stürmer, Sidney Luiz; Salomão, Luiz Carlos Chamhum; Otoni, Wagner Campos; Kasuya, Maria Catarina Megumi

    Resumo em Inglês:

    ABSTRACT The production of inoculum from arbuscular mycorrhizal fungi (AMF) at a large scale and low cost is essential for establishing methods to assist in producing pineapple plantlets with high nutritional and phytosanitary quality. However, this objective is difficult to accomplish because of the biotrophic nature of these fungi. The on-farm multiplication method for AMF inoculum presents a good alternative to supply the demand for the production of glomerospores. This study aimed to multiply and evaluate AMF inoculum originating from isolated species (including Rhizophagus clarus, Claroideoglomus etunicatum) versus native AMF from pineapple and coffee plantations multiplied by the on-farm method on the colonization in pineapple plantlets. Initially, inocula of R. clarus, C. etunicatum, and native AMF (pineapple and coffee) were multiplied by the on-farm method in Sorghum bicolor. After four months, the number of AMF spores and the percentage of viable spores at the layers of 0.00-0.05 and 0.05-0.10 m were evaluated. There were no differences in spore numbers in relation to the source of the inoculum (R. clarus, C. etunicatum, pineapple, and coffee) and evaluated layers, with an average number of 605 spores per 100 cm3 of soil. The percentage of viable spores was greater at the layer of 0.00-0.05 m (76.32 %) compared to the layer of 0.05-0.10 m (72.05 %), regardless of the inoculum source. The viability of the inoculum obtained from C. etunicatum was higher than that from the coffee crop (77.93 and 68.06 %, respectively). Subsequently, the spores were inoculated in pineapple plantlets to assess the rate of colonization. Pineapple plantlets inoculated with AMF had an average of colonization of 18 and 67.73 % after 50 and 180 days cultivation, respectively, with no significant difference being detected between treatments. Therefore, on-farm inoculum production was effective at multiplying the AMF of both isolates of R. clarus and C. etunicatum, as well as for commercial crops (pineapple and coffee), with spores having high viability. Arbuscular mycorrhizal fungi colonized pineapple plantlets independently of the inoculum utilized and favored its growth.
  • Validation of a Standard Operating Procedure (SOP) for Forensic Soils Investigation in Brazil Division – Soil Processes And Properties

    Testoni, Samara Alves; Melo, Vander Freitas; Dawson, Lorna Anne; Salvador, Fábio Augusto da Silva; Kunii, Paulo Akira

    Resumo em Inglês:

    ABSTRACT Soil traces are useful as forensic evidence due to their potential to transfer and adhere to different types of surfaces on a range of objects or persons. Several works have been developed in forensic soils, under different analytical approaches. However, in Brazil, only the researches from the Group of the Federal University of Paraná have developed works with soils under a forensic approach. Focus has been given on the sequential chemical analyses and mineralogical techniques once they presented a large potential to discriminate soil samples, even that originated from the same bedrock. In this way, this work aimed to test a Standard Operating Procedure (SOP) for forensic soil sampling and an analytical protocol in Brazil between the academy and the scientific police through a blind simulated crime scene scenario. Samples were collected at four sites located in the Curitiba Metropolitan Region. All soils were classified as Inceptisol ( Cambissolo ), and the parent material in Curitiba is claystone and in Colombo is limestone. Around 3 g of sample composed by silt + clay fraction were isolated and analyzed by sequential chemical procedure: i) extraction of poorly ordered iron and aluminum oxides with ammonium oxalate (AO); ii) extraction of crystalline iron oxides with sodium dithionite-citrate-bicarbonate (DCB); and iii) extraction of poorly ordered aluminosilicates and gibbsite with NaOH 0.5 mol L-1. All data were transformed by square root and formed a data matrix subsequently analyzed in a principal component analysis (PCA). Most of the samples were properly grouped according to their provenance at all four sites tested, showing the potential of the Standard Operating Procedure (SOP) in a real crime scene. The sampling procedures presented in the SOP were detailed enough to allow the appropriate police work in forensic cases in any part of Brazil. As future considerations, modifications to the sample treatment and analytical protocol could be made depending on the context of the forensic work. Intense anthropogenic activities, such as domestic waste disposal in urban areas, would potentially reduce the discrimination power of such a proposed chemical analytical protocol.
  • Mineralogical Evolution of Magnetic Rhodic Oxisols under Different Lithological Influences in Brazil Division – Soil Processes And Properties

    Silva Filho, Luiz Aníbal; Ker, João Carlos; Fontes, Maurício Paulo Ferreira; Camêlo, Danilo de Lima; Corrêa, Marcelo Metri; Cavalcante, Luis Carlos Duarte; Guimarães, Luciano de Moura

    Resumo em Inglês:

    ABSTRACT Ferrimagnetic Fe-oxides are important soil components, which are present in most of the agricultural soils of Brazil. Distinction, origin, and assessment of the influence of these minerals on magnetism and geochemistry is a challenge for mineralogists. This study aimed to characterize mineralogically Fe-rich Rhodic Oxisols ( Latossolos Vermelhos ) originating from several mafic rocks in Brazil, and assess the implications on their magnetic and geochemical properties. We present results on magnetic measurements, chemical dissolutions, X-ray diffractometry, Rietveld refinement, Raman, and Mössbauer spectroscopies of Fe-rich Rhodic Oxisols originating from several mafic rocks. They show that magnetite is inherited from the parent material, and its oxidation leads to the formation of maghemite. In the coarse fractions (sand and silt), magnetite and maghemite coexist and are interstratified with hematite, confirmed by Raman spectroscopy. This limited the distinction between magnetite and maghemite by Mössbauer spectroscopy. Maghemite represents the only ferrimagnetic Fe oxide in the clay fraction. The influence of both ferrimagnetic minerals, magnetite and maghemite, on magnetic susceptibility and total content of trace elements is determined by the pedogenic development, even among highly weathered soils. In general, the coarse fractions contribute with most of the total trace element contents, while the clay fraction contributes to trace elements availability and magnetic susceptibility of soils.
  • Methane emission induced by short-chain organic acids in lowland soil Division – Soil Processes And Properties

    Moscôso, Janielly Silva Costa; Silva, Leandro Souza da; Pujol, Stefen Barbosa; Giacomini, Sandro José; Severo, Fabiane Figueiredo; Marzari, Laura Brondani; Molin, Gustavo Dal

    Resumo em Inglês:

    ABSTRACT Methane (CH4) is the second major greenhouse gas after CO2, exerting a significant influence on the climate and the chemistry of the atmosphere. In lowland soil, acetate and H2/CO2 are the most important precursors of CH4 and formed from organic matter fermentation in an anaerobic environment, giving rise to short-chain organic acids (ethanoic, propanoic, and butanoic), depending on the type of crop residue and the soil management system. Ethanoic acid can be directly converted to CH4 by methanogenic microorganisms, but propanoic and butanoic acids must be converted to acetate before being converted to CH4. This study aimed to quantify, in isolation, the dynamics and CH4 emission potential of the three short-chain organic acids found in flooded lowland soils with rice crops. The study was carried out in a controlled environment using four standard carbon doses (0, 90, 180, and 270 mg kg−1) of ethanoic, propanoic, and butanoic acids. The dynamics and the potential emission of CH4 from soil were investigated when the acids were applied to flooded soil previously incubated for 20 days. The CH4 emission dynamics were altered with the application of the three short-chain organic acids to the soil, even using an equal amount of carbon. The faster and more intense emission was achieved with the ethanoic acid application in relation to the other two acids application, while butanoic acid presents slower, delayed, and prolonged dynamics of CH4 emission. Propanoic acid resulted in the lowest CH4 emission due to its own stoichiometry and the temperature condition in which the experiment was conducted, which were unfavorable to the hydrogenotrophic bacteria. The addition of short-chain organic acids promoted a priming effect in the soil with conversion values of C to CH4 above the calculated theoretical values.
  • Impact of agro-farming activities on microbial diversity of acidic red soils in a Camellia Oleifera Forest Division – Soil Processes And Properties

    Li, Jun; Wu, Zelong; Yuan, Jun

    Resumo em Inglês:

    ABSTRACT The production of Camellia oleifera (oil tea), typically planted in acidic red soils in southern China, is limited by low soil fertility. Agro-farming is one way to promote soil fertility by increasing organic matter and microbial communities. To understand the impact of agro-farming activity on soil fertility, three types of agro-farming, namely, raising laying hens under forest (RLH), cultivating Lolium perenne grass under forest (LPG), and maintenance of native grass (MNG), were employed in an oil tea farm with acidic red soil in Changsha, China. Soil samples were collected from the farm to estimate microbial communities, pH, and total organic carbon (TOC) in different seasons. The results indicated that TOC and temperature were the dominant factors influencing the variations of bacterial communities, while temperature and pH affected the fungal communities in the soil. The most abundant bacterial phyla were Acidobacteria, Proteobacteria, Actinobacteria, and Chloroflexi , while the most abundant fungal phyla were Ascomycota, Basidiomycota, and Zygomycota . Regardless of treatment, the bacterial richness and diversity were both low in spring, and the fungal richness and diversity in summer and autumn were higher than in spring and winter. The TOC content and pH in LPG were significantly higher than in other treatments. Microbial communities in LPG and MNG were more stable than in RLH. In summary, cultivating grass under forest treatment was the best way to improve the microenvironment with the highest TOC content and fewer pathogenic microorganisms.
  • Summer Cover Crops Shoot Decomposition and Nitrogen Release in a No-Tilled Sandy Soil Division – Soil Processes And Properties

    Weiler, Douglas Adams; Giacomini, Sandro José; Aita, Celso; Schmatz, Raquel; Pilecco, Getúlio Elias; Chaves, Bruno; Bastos, Leonardo Mendes

    Resumo em Inglês:

    ABSTRACT Cover crops have numerous benefits when used in a no-till system. Understanding the processes of decomposition and N release of summer cover crops (SCC) may help select species and management to be used in cropping systems. This study aimed to evaluate C and N loss of SCC shoots. Six SCCs were evaluated: velvet bean (Mucuna aterrima), pearl millet (Pennisetum americanum), dwarf pigeon pea (Cajanus cajan), sunn hemp (Crotalaria juncea), showy rattlebox (Crotalaria spectabilis), and jack bean (Canavalia ensiformis). The experiment was conducted for two years under no-till in soil classified as Typic Hapludalf (Argissolo). The C and N remaining of crop shoots were evaluated for 140 days using litter bags and the results were fitted with a simple nonlinear regression model. Elevated air temperature and rainfall volume accelerated C and N loss in the first year. Carbon and N loss was characterized by a rapid initial phase followed by a slower one. Jack bean had the highest C loss rates, while the lowest rates were found in pearl millet. Velvet bean and pearl millet had the lowest N loss rates in the first year, together with showy rattlebox in the second year. The rates of C (kC) and N (kN) loss were positively correlated with total N and water-soluble C and N in crop shoots. During the 35 days after cover crop termination, SCCs released 35 to 137 kg ha-1 N in 2010 and 5 to 66 kg ha-1 N in 2011. Velvet bean and showy rattlebox showed more gradual N release, which may favor the synchronization between N release and N uptake by the succeeding crop. The sunn hemp was the legume species that combined higher remaining residues on the soil surface, releasing less N but preventing soil erosion.
  • Rhizobial Inoculation and Molybdenum Fertilization in Peanut Crops Grown in a No Tillage System After 20 Years of Pasture Division – Soil Use And Management

    Crusciol, Carlos Alexandre Costa; Ferrari Neto, Jayme; Mui, Tsai Siu; Franzluebbers, Alan Joseph; Costa, Cláudio Hideo Martins da; Castro, Gustavo Spadotti Amaral; Ribeiro, Lívia Cristina; Costa, Nídia Raquel

    Resumo em Inglês:

    ABSTRACT: Peanut (Arachis hypogea) is an important legume grain consumed by humans and utilized for effective nutrient cycling in a diverse cropping system. Areas that have been cultivated with perennial pasture for decades may have nutritional deficiencies and lack a sufficient population of atmospheric nitrogen-fixing bacteria. Molybdenum is an essential micronutrient that is part of the enzyme nitrogenase contained within symbiotic Bradyrhizobium bacteria, which are responsible for fixing nitrogen in legumes. Our objective was to evaluate the effects of application of Mo at different rates and a rhizobial inoculant on peanut growth characteristics. The experiment was conducted in the 2009/2010 growing season in a no-tillage cropping system following 20-year use as pasture [Urochloa brizantha (Syn. Brachiaria brizantha)]. The experimental design was a randomized complete block with four replicates. The main plots were characterized by peanut inoculation with Bradyrhizobium inoculant or without, and the split plots were characterized by different rates of molybdenum (0, 50, 100, and 200 g ha-1) applied to leaves in the form of ammonium molybdate. The nutritional status of plants, nodulation (number of nodules and nodule dry matter per plant), nitrogenase activity, and nitrogenase specific activity were evaluated at 45 and 64 days after emergence (DAE). The yield components and kernel yield were evaluated at the end of the growing season. Nitrogenase enzyme activity at 64 DAE approximately doubled, and the number of pods per plant was greater with inoculation than without, both of which led to greater yields of pods and kernels. In long-term pasture areas, inoculation and molybdenum fertilization greater than the currently recommended rate appear to be necessary to increase pod and kernel yield per hectare of peanut when managed under no-tillage.
  • Spatial and Temporal Potential Groundwater Recharge: the Case of the Doce River Basin, Brazil Division – Soil Use And Management

    Souza, Eliana de; Pontes, Lucas Machado; Fernandes Filho, Elpídio Inácio; Schaefer, Carlos Ernesto Goncalves Reynaud; Santos, Eliana Elizabet dos

    Resumo em Inglês:

    ABSTRACT: Little is known about the groundwater recharge potential of weathered tropical catchments, where increasing water uptake is widespread to meet various water demands. This study aimed to estimate the volume of groundwater recharge of the Doce River Basin, Minas Gerais, Brazil. The BALSEQ model was applied to calculate the water balance over a period of two years (2007-2009). Evapotranspiration, runoff, and potential groundwater recharge (PGR) were calculated, using daily data on rainfall, potential evapotranspiration, and plant-available water. A soil survey was undertaken for all major soils occurring in the basin. Soils samples were used to determine hydraulic conductivity, bulk density, and water content at field capacity and at the permanent wilting point. Vegetation data were obtained from the literature and used to determine the following parameters: canopy interception, crop coefficient, and root depth. The estimated groundwater was spatially predicted using the Random Forests model with digital elevation, vegetation index, pedological, lithological, and climate maps. During the two years, an average of 32 % of rainfall was converted to groundwater. Annually, the percent of rainwater converted to groundwater varied between 27 and 48 % for all soil classes, highlighting the great temporal variability. The spatial prediction showed a volume of approximately 17,484 and 35,410 m3 of rainfall being converted to groundwater for the first and second year, respectively. The BALSEQ model showed a feasibility for the water balance calculation and can be reapplied for updating the groundwater maps of the Doce River Basin. These maps could then be used to guide land use planning programs, with the aim to protect water resources.
  • Impacts of Pig Slurry Applied to Two Different Soils on Nutrient Transport by Runoff Division – Soil Use And Management

    Kaufmann, Danieli Schneiders; Bertol, Ildegardis; Santos, Maria Aparecida do Nascimento dos; Bagio, Barbara; Mecabô Júnior, José; Borg, Heinz

    Resumo em Inglês:

    ABSTRACT: Runoff in agricultural areas with intensive application of pig slurry can transport significant amounts of nutrients. This study evaluates the effects of different pig slurry (PS) application rates (0, 50, 100, and 200 m3 ha-1) on nutrient loss through runoff during soybean cultivation under no-tillage. It was conducted at two sites in southern Brazil, one on an Alfisol (27° 43' south and 50° 3' west) and one on an Inceptisol (27° 47' south and 50° 18' west). The PS was applied to the soil once at the beginning of the soybean cycle. Each plot was 11 m long in the direction of the slope and 3.5 m wide. To induce runoff, artificial rainfall was applied in four different tests (T1, T2, T3, T4), with an intensity of 65 mm h-1 for 90 minutes. The first test was performed one day after PS application, while the other tests were performed throughout the soybean cycle. During each test, runoff samples were collected at 10-min intervals after the beginning of runoff. The runoff amount and the NO3-, NH4+, P, and K+ concentrations in the runoff were measured. In T1, nutrient transport from the Alfisol and the Inceptisol increased with increasing PS doses. In some cases, this effect was still noticeable in T2 and T3, but not in the last test (T4). The transported amounts of NO3-, NH4+, P, and K+ decreased as the period between PS application and simulated rainfall increased. Regardless of the soil and the treatment, NO3- was transported in the greatest quantities, followed by K+, NH4+, and P.
  • Acid Ammonium Citrate as P Extractor for Fertilizers of Varying Solubility Division – Soil Use And Management

    Santos, Wedisson Oliveira; Mattiello, Edson Marcio; Barreto, Matheus Sampaio Carneiro; Cantarutti, Reinaldo Bertola

    Resumo em Inglês:

    ABSTRACT: There are several globally accepted methods to chemically characterize P-fertilizers, but not all are suitable to predict the agronomic efficiency of the P sources in terms of plant nutrition. Our aim was to investigate the performance of P extractors for fertilizers, investigating the consistency of different methods for P sources of varying properties and the related plant responses. The experiment was carried out in a greenhouse, using corn as a model plant. Phosphorus values extractable in water, 2 % citric acid, 2 % formic acid, ammonium neutral citrate + water, and acid ammonium citrate were evaluated for eight P fertilizers of varied solubility and correlated with P uptake by corn. The extractors citric acid and formic acid recovered no predictive amounts of P from crystalline apatite sources (Araxá and Patos phosphate rocks, PRs). However, they showed a satisfactory performance for Bayóvar PR and partially acidulated PRs but extracted low amounts of P from soluble P sources such as superphosphates. Neutral ammonium citrate + water extractors could accurately predict the efficiency of soluble P sources but underestimated the performance of Bayóvar (a reactive PR). In contrast, the extractor acid ammonium citrate, AAC, (pH 3) accurately predicted the agronomic efficiency of all P fertilizers. We therefore suggest AAC as an effective predictor of the agronomic effectiveness of any inorganic phosphorus sources.
  • Tipping Bucket Prototype for Automatic Quantification of Surface Runoff Rate in Plots Division – Soil Use And Management

    Somavilla, André; Gubiani, Paulo Ivonir; Zwirtz, Anderson Luiz

    Resumo em Inglês:

    ABSTRACT: Quantification of runoff rate is an onerous task with non-automated devices; it requires a lot of manual labor to perform measurements. In this study, an automatic device to quantify the surface runoff rate from plots with a small area was developed and tested. The prototype was based on the tipping bucket technique and built with reused materials. Its performance was tested in the laboratory and a calibration curve was developed to improve measurement accuracy. The device can be used for automatic quantification of surface runoff in small plots, with a flow rate of less than 750 × 103 mm3 min-1. The device can be built with different dimensions to measure different flow rates. In that case, the error measurements and calibration curve must be recalculated.
  • Potassium Fertilization of Eucalyptus in an Entisol in Low-Elevation Cerrado Division - Soil Use And Management

    Gazola, Rodolfo de Niro; Buzetti, Salatiér; Teixeira Filho, Marcelo Carvalho Minhoto; Gazola, Raíssa Pereira Dinalli; Celestrino, Thiago de Souza; Silva, Alexandre Costa da; Silva, Paulo Henrique Müller da

    Resumo em Inglês:

    ABSTRACT Potassium (K) is one of the most highly accumulating nutrients in Eucalyptus and, consequently, is heavily exported by the harvesting of wood. Moreover, its availability in the soil in most Brazilian plantation areas is very low, especially in the regions of the Cerrado biome, which has soils with low natural fertility and marked water deficits, implying a lack of nutrient supply and, consequently, a less efficient water use. Our objective was to evaluate the effects of K fertilization on Eucalyptus biomass yield, the addition of nutrients to the soil by leaf deposition, nutrient use efficiency, and soil K availability. The experiment was conducted with clone I144 (Eucalyptus urophylla) in the municipality of Três Lagoas/MS, in a Neossolo Quartzarênico Órtico (Entisol). The experimental design was a randomized block with four treatments and five replicates. The treatments consisted of four K doses (0, 90, 135, and 180 kg ha-1 of K2O) as KCl. Plant biomass production (leaves, branches, trunk, and bark), senescent leaf deposition, leaf nutrient concentrations, nutrient accumulation in the different plant compartments, nutrient use efficiency, addition of nutrients to the soil by leaf deposition, and soil K availability were evaluated. Potassium fertilization increased the biomass yield of Eucalyptus plants, senescent leaf K content, the transfer of K to the soil, the accumulation of K in the aerial plant parts, and the K content in the soil. However, it did not influence senescent leaf deposition yield or plant K use efficiency.
  • Crop Yield Responses to Sulfur Fertilization in Brazilian No-Till Soils: a Systematic Review Division - Soil Use And Management

    Pias, Osmar Henrique de Castro; Tiecher, Tales; Cherubin, Maurício Roberto; Mazurana, Michael; Bayer, Cimélio

    Resumo em Inglês:

    ABSTRACT Sulfur (S) fertilization recommendations for grain crops in Brazil were formerly established from studies on crops with a low yield potential grown on soils under conventional tillage (CT). However, the subsequent adoption of no-tillage (NT) altered S dynamics in the soil, making it necessary to carefully evaluate the applicability of these S fertilizer recommendations. In addition, the emergence of modern high-yield-potential genotypes, the successive application of concentrated low-sulfur fertilizers, and reduction in S atmospheric deposition have raised the likelihood of positive responses of crops to S fertilization. Available literature reports contrasting crop responses to S fertilization in Brazilian soils, ranging from substantial gains to slight yield losses depending on the particular crop, soil, and climate. The primary aim of this study was to examine available data for crop grain responses to S application in NT soils in order to ascertain whether existing recommendations established for Brazilian CT soils also hold for NT soils. A systematic review of data from 35 scientific publications spanning 58 crop harvests revealed a positive yield response to S fertilization in 31 % of the crop harvests, with an average yield increase of 16 %. Crops on soils with available SO42–-S contents above the critical level (viz., 7.5 mg dm-3) exhibited no positive response to S fertilization in any crop harvest (n = 18). Dry edible bean and corn were the most responsive crops, and canola and wheat, the least. For the trials with positive crop responses, a fertilizer rate of 26 kg ha-1 S sufficed to obtain at least 95 % of the maximum possible yield. In general, the S fertilization recommendations previously established for CT soil proved effective with grain crops on NT soils as a result of the critical levels of soil available SO42--S and the fact that the recommended S rates are similar to those found in this study considering trials conducted under NT conditions only. However, existing recommendations could be improved by using additional criteria for soils with available SO42--S contents below the critical level since a positive response was observed in 22 % (n = 18) and 92 % (n = 12) of the crop harvests under a subtropical and a tropical climate, respectively. Our results suggest that S fertilization must be prioritized in NT soils with available SO42--S contents below 7.5 mg dm-3 in the 0.00-0.20 m layer, especially in tropical climate zones. In addition, regional fertilizer recommendation guidelines should consider crop type and yield expectation in order to facilitate more sustainable S management and increased crop yields in Brazil.
  • Sugarcane Root Development and Yield under Different Soil Tillage Practices Division - Soil Use And Management

    Moraes, Emmerson Rodrigues de; Mageste, José Geraldo; Lana, Regina Maria Quintão; Torres, José Luiz Rodrigues; Domingues, Luis Augusto da Silva; Lemes, Ernane Miranda; Lima, Luara Cristina de

    Resumo em Inglês:

    ABSTRACT New strategies for sugarcane production have been very important since the incorporation of ethanol in the Brazilian energy mix in the early 1970s. Prior to planting sugarcane, the soil is prepared, and this process can affect root development and, consequently, sugarcane production. This study was conducted in an area of sugarcane crop renewal in the Cerrado biome (Brazilian tropical savanna), with the objective of identifying which tillage system generates the better root development and improved yield in sugarcane. The treatments were: 1) weed desiccation + moldboard plowing (0.4 m) + mild spike tooth harrowing (0.15 m); 2) subsoiler (0.3 m) + mild spike tooth harrowing (0.15 m); 3) weed desiccation + no-tillage (furrow opening and fertilizer); 4) weed desiccation + subsoiler (0.4 m); 5) ratoon destruction + subsoiler (0.4 m); 6) ratoon destruction + spike tooth harrowing (0.2 m) + moldboard plowing (0.4 m) + mild spike tooth harrowing (0.15 m). Characteristics of the sugarcane root system, such as the root length density, average distance between roots, and root soil exploration, after the first harvest (1.5 years) were studied. Root length density was greater for the treatments that included plowing (0.4 m) and harrowing (0.15 m) operations. The average distance between roots was low in the no-tillage system. The highest sugarcane yield in the plant crop was achieved by management practices with more extensive soil profile disturbances, like plowing followed by harrowing.
  • Phosphorus Fractions in Soil with Organic and Mineral Fertilization in Integrated Crop-Livestock System Division - Soil Use And Management

    Rigo, Amanda Zolet; Corrêa, Juliano Corulli; Mafra, Álvaro Luiz; Hentz, Paulo; Grohskopf, Marco André; Gatiboni, Luciano Colpo; Bedendo, Gizelle

    Resumo em Inglês:

    ABSTRACT Use of organic fertilizers in integrated crop-livestock (iCL) systems may affect soil phosphorus fractions. This study aimed to determine phosphorus fractions in the soil under the iCL system after six years of application of organic or mineral fertilizers. The experiment was conducted on a Rhodic Kandiudox (Nitossolo Vermelho Distroférrico) in a randomized block design, using a 5 × 3 + 1 factorial scheme, with four replicates. The treatments consisted of three organic fertilizers (poultry litter, pig slurry, and compost) and two mineral fertilizers (M1, equivalent to pig slurry; and M2, equivalent to poultry litter) in interaction with three application rates, corresponding to 75, 100, and 150 % of the fertilizer recommendation for the crop of interest and a control (with no fertilizer). Soil sampling was performed in the 0.00-0.05, 0.05-0.10, and 0.10-0.20 m layers for determination of the phosphorus fractions. Successive use of organic or mineral fertilizers for six years in the iCL system considerably raises the labile and moderately labile P fractions up to the 0.20 m depth and, with less intensity, raises the non-labile fractions up to the 0.10 m depth. The soil P increase associated with fertilizer input raises soybean and corn yields, and it does not exceed the critical P limit according to local environmental legislation.
  • Timing and Splitting of Nitrogen Side-Dress Fertilization of Early Corn Hybrids for High Grain Yield Division – Soil Use And Management

    Panison, Fernando; Sangoi, Luís; Durli, Murilo Miguel; Leolato, Lucieli Santini; Coelho, Antonio Eduardo; Kuneski, Hugo Francois; Liz, Vander Oliveira de

    Resumo em Inglês:

    ABSTRACT Currently, most nitrogen fertilizer is side-dressed when corn is in the four (V4) to eight (V8) expanded leaf stage. However, recent studies have shown that modern hybrids take up high amounts of nitrogen during grain filling. This indicates that a late nitrogen fertilization, at the time of crop flowering, may be important to optimize corn agronomic performance. This study aimed to evaluate the effect of the timing and splitting of nitrogen side-dress application on the agronomic performance of early corn hybrids in order to achieve high grain yield. The experiment was set in Lages, Santa Catarina, in the South of Brazil, during the 2014/2015 and 2015/2016 growing seasons. A randomized block design arranged in split plots was used. Two hybrids were tested in the main plots: P1680YH (very early) and P30F53YH (early). Six nitrogen side-dress systems were assessed in the split plots: control (without N), full N rate applied at V5, full N rate applied at V10, 1/2 N rate applied at V5 and 1/2 at V10, 1/3 N rate applied at V5, 1/3 at V10 and 1/3 at VT; and the whole N rate applied at VT. The nitrogen rate was 300 kg ha-1 N. Urea was used as the nitrogen source. Total grain yield and yield components, agronomic nitrogen use efficiency, and leaf area were determined. Grain yield ranged from 6,422 to 15,426 kg ha-1 in 2014/2015 and from 9,283 to 14,986 in 2015/2016. Nitrogen side-dress application performed one time at V5 or V10 or split into two or three applications at different growth stages had similar grain yield, number of ears per plant, kernels per ear, and 1,000 grain dry weight. Nitrogen side-dressed entirely at VT led to higher grain yield than the control. However, grain yield and agronomic nitrogen use efficiency were lower in this treatment than in the treatments involving the other growth stages of side-dress nitrogen. The early hybrid was higher yielding than the very early hybrid, regardless of the timing of nitrogen fertilization. Splitting of nitrogen fertilization up to tasseling was not an effective strategy to increase grain yield and agronomic nitrogen use efficiency of the corn hybrids P30F53YH and P1680YH.
  • Physical, Chemical, and Microbiological Properties of Soil under Different Plant Covers in the Seridó Desertification Region in the Brazilian Semiarid Division – Soil Use And Management

    Martins, Adriana Ferreira; Salcedo, Ignácio Hernan; Oliveira, Flávio Pereira de; Pereira, Walter Esfrain

    Resumo em Inglês:

    ABSTRACT The Seridó Desertification Region is a result of inadequate management of the native Caatinga vegetation, which generated degraded areas with little or no capacity for plant production. The area has experienced a succession of different land uses, but little is known about the impact of these changes. The present study tested the hypothesis that the intense degradation of the Caatinga drastically decreased vegetal biomass production, which favored direct soil exposure and resulted in a lower abundance and diversity of species and groups of vegetation as well as microorganisms. This study aimed to quantify some of the main physical, chemical, and microbiological properties of Alfisol ( Luvissolo Crômico órtico lítico ) and Entisol ( Neossolo Litólico eutrófico típico ) under different plant covers in the Seridó Desertification Region, in the municipality of Parelhas, in the state of Rio Grande do Norte (RN), Brazil. Three different areas were studied: an area of preserved Caatinga, a recovery area with jurema [ Mimosa tenuiflora (Willd.) Poir.], and a degraded area. Soil samples were collected from the 0.00-0.10 m soil layer and later characterized in terms of their physical and chemical properties. The microbiological characteristics analyzed were microbial activity (microbial biomass carbon and microbial respiration) and glomalin. The soil under the Caatinga vegetation exhibited better properties than the other analyzed soils. Aggregate stability was the physical property with the highest potential for differentiating between areas. Glomalin, which is associated with the presence of mycorrhizae, and which, in turn, is related to the uptake of P, which is often deficient in these soils, was the most discriminating microbiological variable according to an analysis of canonical variables. The total of Ca2+ and Mg2+ was the most discriminating chemical properties, and played a positive role in soil aggregation, especially Ca2+.
  • Nitrous Oxide Emissions in No-Tillage Onion ( Allium cepa L.) Crops Are Increased by Oilseed Radish Cover Crop and Poultry Manure Application Division – Soil Use And Management

    Müller Júnior, Vilmar; Koucher, Leoncio de Paula; Souza, Monique; Lima, Andria Paula; Kurtz, Claudinei; Couto, Rafael da Rosa; Lovato, Paulo Emílio; Giacomini, Sandro José; Brunetto, Gustavo; Comin, Jucinei José

    Resumo em Inglês:

    ABSTRACT The use of cover crops and poultry manure (PM) is an alternative to reduce the use of synthetic inputs and can contribute to the nutrient cycling in onions ( Allium cepa L.) grown under a no-tillage system. However, this management practice may contribute to an increase in N2O emissions to the atmosphere. The aims of this study were to evaluate the immediate effect on N2O emissions of adding PM onto cover crop residues and to verify the effect of different no-tillage systems on N2O emissions. Two studies (laboratory and field) were conducted with the addition of oilseed radish (OR), black oat (BO), and weed (WD) residues with and without PM under a no-tillage (NT) system. Emission of N2O (kg ha-1) was influenced by the different residue-management systems and was higher in treatments with OR residues (2.96 ± 0.67 kg ha-1 for OR and 5.28 ± 1.04 kg ha-1 for OR + PM). The other treatments behaved similarly with emissions of approximately 1.91 ± 0.17 kg ha-1 of N-N2O. The highest N2O emissions in the field study were found within the first 15 days and represented 50.3 % of the average emissions. Poultry manure showed high emissions when the cover crop was OR, but not when it was BO and WD.
  • Does Ferralsol Clay Mineralogy Maintain Potassium Long-Term Supply to Plants? Division – Soil Use And Management

    Moterle, Diovane Freire; Bortoluzzi, Edson Campanhola; Kaminski, João; Rheinheimer, Danilo dos Santos; Caner, Laurent

    Resumo em Inglês:

    ABSTRACT Ferralsols ( Latossolos ) should contain few or no 2:1 clay minerals and have low potassium (K) contents, and consequently low levels of non-exchangeable K forms are expected. The aim of this study was to evaluate how the clay mineralogy of a Ferralsol affects the soil K dynamics in response to K fertilization during cropping and whether the clay mineralogy was altered due to successive crops and K fertilization. A tropical Brazilian Ferralsol under field conditions was sampled (0.00-0.20 m) in contrasting K fertilization plots: no K application (control plot) and 3,200 kg ha-1 applied K2O fertilizer. These two treatments were submitted at eight different crop cycles, performed in pots under greenhouse conditions, and fertilized with 0, 30, and 90 mg kg-1 K2O before each crop cycle. The biomass K, exchangeable K, non-exchangeable K, and structural K contents were determined after each crop cycle. At the end of the experiment, the presence of 2:1 clay minerals with hydroxy-aluminum interlayered in the soil clay fraction was verified, which ensured K adsorption in a form available to plants when K fertilizer was added. Cropping without K fertilization resulted in limited crop yields and exhausted the exchangeable and non-exchangeable K soil reserves. The previous K fertilization history influenced the soil K reserve and its availability to plants in the Ferralsol studied. The crops without K addition decreased the proportion of 2:1 hydroxy-Al interlayer minerals in the soil in relation to the kaolinite clay minerals.
  • Optimal Simulation of the Land-Use Structure Based on the Local Ecological Environment: the Case of Huanghua City in Hebei Province, China Division – Soil Use And Management

    Chen, Ying; Cui, Jianghui; He, Ling; Men, Mingxin

    Resumo em Inglês:

    ABSTRACT The overuse of land has resulted in a sharp decline in ecological functions, affecting the environment as it relates to the existence and sustainable development of the whole biosphere. This work aims to evaluate the ecological and economic efficiencies of the land-use structure. A simulation model, CLUE-S (Conversion of Land-Use and its Effects at Small Region Extent), and an integrated model based on the MOP (Multi-Objective Program) and CLUE-S were applied to assess the suitability of unutilized lands in Huanghua City, China. This was to simulate the optimal structure of land-use in the research zone to avoid loss of the land ecological service functions and the decreasing values with rapid changes in the land-use structure. By the year 2020, the simulation of the single model shows that the economic efficiency is expected to increase, but the ecological efficiency will decline. Depending on the evaluation of the suitability of unutilized land and the optimization results of the integrated MOP- and CLUE-S-based models, the ecological and economic efficiencies are expected to increase by 1.17 and 2.23 %, respectively, compared with those in 2012. In addition, the sum of the two land functions will increase for the integrated MOP- and CLUE-S-based model by the year 2020 compared with the single model. Consequently, the ecological efficiency will significantly increase. However, the optimization solution based on the integrated MOP and CLUE-S model is better than the one based on the CLUE-S model.
  • Decomposition and Nutrient Release of Cover Crops in Mango Cultivation in Brazilian Semi-Arid Region Division – Soil Use And Management

    Freitas, Maria do Socorro Conceição de; Souto, Jacob Silva; Gonçalves, Mariana; Almeida, Larissa Emanuelle da Silva; Salviano, Alessandra Monteiro; Giongo, Vanderlise

    Resumo em Inglês:

    ABSTRACT Knowledge of the decomposition dynamics of aboveground phytomass and its release of nutrients in mixtures of cover crops as well as the impact on the soil tillage system is fundamental for the sustainable management of agroecosystems. This work aimed to evaluate whether soil tillage and the choice of cover crops cultivated in the interrows can be technological strategies to increase dry biomass production, increase the capacity to add carbon, and improve macronutrient cycling in a mango ( Mangifera indica L.) orchard in a semi-arid environment. The field experiment (sixth year) consisted of two soil tillage systems (NT-no tillage and CT-conventional tillage) combined with three plant mixtures (PM1-75 % leguminous + 25 % grasses and oilseed species, PM2-25 % leguminous + 75 % grasses and oilseed species, and SV - spontaneous vegetation). Phytomass production and nutrient accumulation were not affected by the soil tillage system, but PM1 had the highest phytomass production and accumulations of C, N, and K, and it was significantly superior to SV. Regardless of the type of plant mixture, cultivated or spontaneous, soil tillage increased the rates of phytomass decomposition and nutrient release evaluated for 315 days after the cover plant management. The PM1 had the highest rates of decomposition and release of P and K, followed by PM2 and SV. There was no difference between the mixtures for the release of N, Ca, and Mg. The use of a mixture of cover crops, regardless of the predominance of leguminous or non-leguminous species, and a no-tillage system were technological strategies that could be adopted to favor the addition of soil carbon and nutrient cycling in fruit agroecosystems in the Brazilian semi-arid region. Spontaneous vegetation, due to its capacity to accumulate nutrients and the recalcitrant characteristics of its phytomass, has the potential to cycle nutrients and keep the soil covered. In addition, spontaneous vegetation should be better investigated because it is a low-cost strategy in agroecosystem designs.
  • Assessment of Trace Element Contents in Soils and Water from Cerrado Wetlands, Triângulo Mineiro Region Division – Soil Use And Management

    Ribeiro, Bruno Teixeira; Nascimento, Diogo Costa; Curi, Nilton; Guilherme, Luiz Roberto Guimarães; Costa, Enio Tarso de Souza; Lopes, Guilherme; Carneiro, João Paulo

    Resumo em Inglês:

    ABSTRACT In the Brazilian Cerrado biome, there are wetlands locally known as “Veredas”, which are swampy plains between hills and rivers. Since the 1970’s, the Cerrado biome has been gradually converted to livestock, crop, or forestry production. Until now, very few studies were conducted to evaluate the baseline contents of trace elements in Cerrado wetland soils. Due to their position in the landscape (bottom lands), the wetlands are potentially susceptible to contamination by runoff and/or leaching from surrounding areas at higher altitudes. This work evaluated the As, Cd, Pb, Ni, Zn, Cu, Mn, and Fe contents in soils from six wetlands (undisturbed and disturbed) in the Minas Gerais Triangle region, Brazil. In each wetland, we collected topsoil samples (0.00-0.20 m layer) and subsurface samples (0.40-0.70 m layer) at different landscape positions in the wetlands (upper, middle, and bottom positions). The soil samples were air-dried, ground, and sieved through 2-mm mesh. Afterwards, the soil digestion was performed according to the USEPA 3051A protocol, and the trace elements were determined by atomic absorption spectrometry (flame or graphite furnace atomization). Water samples were also collected monthly from September 2014 to September 2015 to determine the elemental composition by inductively coupled plasma optical emission spectrometry. The contents of all soil trace elements studied were below the threshold values established by Brazilian guidelines. The soil trace element (cations and/or oxyanions) distributions varied according to soil depth and organic matter content. Our findings contribute to the sparse inventory of Brazilian Cerrado wetlands regarding trace-element contents.
  • Nitrate Reductase Activity and Nitrogen and Biomass Accumulation in Sugarcane under Molybdenum and Nitrogen Fertilization Division – Soil Use And Management

    Santos, Renato Lemos dos; Freire, Fernando José; Oliveira, Emídio Cantídio Almeida de; Freire, Maria Betânia Galvão dos Santos; West, Jason Brossard; Barbosa, José de Arruda; Moura, Maria José Alves de; Bezerra, Patrícia da Costa

    Resumo em Inglês:

    ABSTRACT Prior research on sugarcane showed increment of productivity following molybdenum (Mo) fertilization and some indication of the potential role either on nitrate reductase activity (NRA). However, this increment can depend on sugarcane variety and nitrogen (N) fertilization. This study aimed to evaluate the effect of Mo fertilization on Mo uptake, on NRA, nitrate (NO3--N), and ammonium (NH4+-N) contents in leaves and roots of sugarcane, and the accumulation of N and biomass across two sugarcane varieties (RB 867515 and RB 92579). The varieties were subjected to two rates of N fertilization (without N fertilization and 60 kg ha-1 of N) and two rates of Mo fertilization (without Mo fertilization and 200 g ha-1 of Mo). At 70, 100, 130, 200, and 365 days after planting (DAP), the following parameters were determined: Mo, NO3--N and NH4+-N contents, NRA in the leaves and roots, and the accumulation of N, as well as shoot dry matter (SDM). Molybdenum fertilization increased N accumulation in 36 and 44 % in the varieties RB 867515 and RB 92579, respectively. This increase in N accumulation was associated with NRA stimulation of 13 % in the leaves and 42 % in the roots. The maximum NRA occurred around 100 DAP, and its contents in the leaves and roots of the RB 92579 were 0.83 and 0.46 µmol NO2- g-1 h-1 of fresh matter, respectively, and in RB 867515 these values were 0.61 and 0.43 µmol NO2- g-1 h-1 of fresh matter, respectively. The assimilation of NO3--N was increased with Mo application, both with and without N fertilization, suggesting that Mo fertilization is indicated in nutrition management of sugarcane. This study provides insight into how Mo fertilization interacts with N fertilization and sugarcane varieties, altering N accumulation and dry matter production.
  • Reference Values of Grain Nutrient Content and Removal for Corn Division – Soil Use And Management

    Duarte, Aildson Pereira; Abreu, Mônica Ferreira de; Francisco, Eros Artur Bohac; Gitti, Douglas de Castilho; Barth, Gabriel; Kappes, Claudinei

    Resumo em Inglês:

    ABSTRACT: Unchanged reference values of grain nutrient contents for corn have been used for over 20 years, despite yield increases, the development of new hybrids, and modifications to cropping systems, especially the establishment of in-season second crops and the wide adoption of no-tillage. This study measured macro- and micronutrient contents in corn grains from different regions, in the first (summer) and second (fall) crop, to update the reference values of estimated nutrient removal. A secondary objective was to determine whether there were correlations between grain nutrient contents and grain yields and densities. In this study, 175 corn grain samples of experiments on cultivar evaluation and 22 samples from soil management trials from five states (SP, PR, MG, MT, and MS) were used. Grain nutrient contents were ranked as follows: N > K > P > Mg > S (g kg−1) and Ca > Zn > Fe > Mn > B > Cu (mg kg−1). Content values for half of the nutrients analyzed were negatively correlated with yield and/or seed weight, whereas grain density was not correlated with nutrient contents. For the first crop of corn, the N, S, and Cu contents clearly decreased with increases in grain yield and seed weight, indicating a lower nutrient removal at higher yields. The great variability of results among environments makes it difficult to differentiate between the first and second crop of corn. The reference values currently in use overestimate the removal of N, P, K, Ca, Mg, S, and Zn grain contents, but underestimate Cu and B in corn. The results of this study can be used to update the reference values of nutrient contents of corn grains to better estimate nutrient removal from the soil.
  • Ammonia Volatilization from Soil-Applied Organic Fertilizers Division – Soil Use And Management

    Rocha, Adriano Alvim; Araújo, Ednaldo da Silva; Santos, Silvio da Silva; Goulart, Jhonatan Marins; Espindola, José Antonio Azevedo; Guerra, José Guilherme Marinho; Alves, Bruno José Rodrigues; Rouws, Janaina Ribeiro Costa

    Resumo em Inglês:

    ABSTRACT: A reliable quantification of nitrogen (N) losses by ammonia (NH3) volatilization can contribute to identifying optimized strategies of fertilizer management. The objective of this study was to quantify ammonia volatilization from several organic N sources incorporated into or applied onto the soil surface. Two cultivation areas, under snap bean and corn, were evaluated at Embrapa Agrobiology, Seropédica, Rio de Janeiro (RJ). Both experiments used a randomized complete block design in split-plots, with four replications. The main plots consisted of four organic fertilizers (castor bean cake, bokashi, legume fertilizers, cattle manure), at rates of 200 kg ha-1 N, and a control treatment (without fertilization), and the subplots corresponded to the management forms (incorporated or surface-applied) of the fertilizers. In the first experiment, snap bean cv. Novirex was grown in winter/spring and in the second, corn cv. Catingueiro in summer/autumn. In each subplot, static semi-open NH3 collectors were installed. We conclude that surface-applied castor cake was the organic fertilizer with highest N loss by NH3 volatilization. A comparison of the management systems (incorporated or surface-applied) showed that volatilization from organic fertilizers incorporated into the soil was significantly lower, with a reduction of 80 % for castor cake, of 78 % for bokashi and 67 % for legume fertilizer. Nitrogen loss through ammonia volatilization varied, from rates of 3 to 25 % in winter/spring and from 2 to 38 % in summer/autumn, according to the organic fertilizer applied. The period required to recover 95 % of the N lost by NH3-N volatilization was between 13 to 18 days for castor cake; 14 to 43 days for bokashi; 17 to 49 days for legume fertilizer and more than 43 days for cattle manure.
  • Phosphate Sources and Filter Cake Amendment Affecting Sugarcane Yield and Soil Phosphorus Fractions Division – Soil Use And Management

    Soltangheisi, Amin; Santos, Valdevan Rosendo dos; Franco, Henrique Coutinho Junqueira; Kolln, Oriel; Vitti, André Cesar; Dias, Carlos Tadeu dos Santos; Herrera, Wilfrand Ferney Bejarano; Rodrigues, Marcos; Soares, Thais de Marchi; Withers, Paul John Anthony; Pavinato, Paulo Sergio

    Resumo em Inglês:

    ABSTRACT: The use of mineral phosphate fertilizers associated with organic residues can improve fertilizer use efficiency and consequently decrease their usage costs. Soil application of filter cake (FC) can provide nutrients and enhance physical quality. This study aimed to evaluate the effects of different phosphate fertilizers [rock phosphate (RP) and triple superphosphate (TSP)] applied at different rates (90 and 180 kg ha-1 P2O5) associated with filter cake (10 Mg ha-1 dry matter) on the soil phosphorus (P) fractions after two consecutive seasons of sugarcane in two distinct soils, sandy and clayey. Yield was significantly improved with FC addition in the first year in both soils, while inorganic P sources did not influence crop yield at either location and in both years. Organic and residual P forms were only slightly altered in the sandy soil. The most significant changes occurred in the labile and moderately labile P fractions in both soils. Filter cake was an effective source of nutrients for plant development, increasing the levels of soil available P and keeping it at agronomically adequate levels for up to two years, however it was not able to facilitate the P release from mineral fertilizers, irrespective of the source or rate.
  • Emissions of Nitrous Oxide and Methane in a Subtropical Ferralsol Subjected to Nitrogen Fertilization and Sheep Grazing in Integrated Crop-Livestock System Division – Soil Use And Management

    Piva, Jonatas Thiago; Sartor, Laércio Ricardo; Sandini, Itacir Eloi; Moraes, Anibal de; Dieckow, Jeferson; Bayer, Cimélio; Rosa, Carla Machado da

    Resumo em Inglês:

    ABSTRACT Brazilian agriculture contributes significantly to nitrous oxide (N2O) and methane (CH4) emissions, so the understanding of such emissions at the field is crucial for mitigation strategies. This study quantified the impact of N application and sheep grazing on the N2O and CH4 emissions from a subtropical Ferralsol under an integrated crop-livestock (ICL) management system. In a long-term experiment in southern Brazil, gaseous fluxes were measured during a year-long cycle of ryegrass (Lolium multiflorum) plus oats (Avena sativa) winter pasture and a summer crop of common beans (Phaseolus vulgaris). Three rates of urea-nitrogen (0, 75, and 150 kg ha-1) were applied to the winter-pasture, which was subjected to two sheep grazing levels (continuously grazed, and ungrazed). The experiment had a complete randomized block design with three replicates. Soil N2O and CH4 fluxes were measured with closed static-chambers (0.20 m high × 0.25 m in diameter). Nitrous oxide emission peaks occurred 28 days after N application and increased with N application rate. Accordingly, the cumulative N2O emissions averaged across grazed and ungrazed treatments increased from 0.45 kg ha-1 in the control soil to 1.78 and 2.10 kg ha-1 after application of 75 and 150 kg ha-1, respectively. The N2O emission factors were 1.7 and 1.1 % when the N rates were 75 and 150 kg ha-1, respectively. The cumulative average N2O emission for all N rates was 2.09 kg ha-1 in ungrazed pasture, but it was reduced by 62 % with grazing to 0.80 kg ha-1, perhaps because of a possible denitrification of N2O to N2 associated with soil compaction from trampling. Overall, fertilizer-N is an important source of N2O from soil under ICL based on sheep grazing, with emission factors consistent with the IPCC’s default of 1 % (0.3-3.0 %). Grazing reduced the emission of soil N2O, but the underlying cause of that reduction needs to be better understood.
  • Ecotoxicology of Pig Slaughterhouse Waste Using Lactuca sativa L., Raphanus sativus L., and Oryza sativa L. Division – Soil Use And Management

    Ramires, Maiara Figueiredo; Souza, Eduardo Lorensi de; Fontanive, Daniel Erison; Bianchetto, Renan; Krynski, Ângelo Munaretto; Cezimbra, Júlio Cesar Grasel; Antoniolli, Zaida Inês

    Resumo em Inglês:

    ABSTRACT Pork is the most consumed animal protein around the world. The production levels are significant, which results in the generation of large amounts of slaughter waste. Such waste is often disposed of improperly in agricultural areas, causing environmental imbalance by the contamination of soil and water sources with metals and pathogenic organisms. This study evaluates the phytotoxic effects of pig slaughterhouse waste in natura and after stabilization processes on lettuce (Lactuca sativa Linnaeus, 1753), radish (Raphanus sativus Linnaeus, 1753), and rice (Oryza sativa Linnaeus, 1753), in addition to shoot nutrient contents. To do this, the waste was evaluated through phytotoxicity tests on lettuce, radish, and rice plants in natura (PSWin) as well as after aerated composting (PSWa), natural composting (PSWn), and vermicomposting (PSWv). The evaluations were done through germination, root length, plant development, and shoot nutrient analysis. We found that PSWin and PSWa negatively affected germination, root length, and plant development. Shoot nutrient contents varied greatly among treatments, some of which were above, below, or within the recommended limits. Based on these results, we infer that pig slaughterhouse waste in natura and after aerated composting is phototoxic to lettuce, radish, and rice plants. Phosphorus and sulfur exhibited contents above those recommended in all the treatments for lettuce, radish, and rice. On the other hand, potassium and calcium contents were below the recommended thresholds.
  • Assessing the Content of Micronutrients in Soils and Sugarcane in Different Pedogeological Contexts of Northeastern Brazil Division – Soil Use And Management

    Silva, Rita de Cássia Ferreira da; Silva, Fernando Bruno Vieira da; Biondi, Caroline Miranda; Nascimento, Clístenes Williams Araújo do; Oliveira, Emídio Cantídio Almeida de

    Resumo em Inglês:

    ABSTRACT Micronutrient research for sugarcane in northeastern Brazil is scarce and most works on this issue date back to the 70’s and 80’s. The objectives of this study were to assess the available and reserve pools of Fe, Mn, Cu, and Zn in soils cultivated with sugarcane under three geological contexts in northeastern Brazil as well as to diagnose the micronutrient nutritional status of sugarcane grown on these areas in order to identify pedogeological conditions in which micronutrient deficiencies are likely. Results showed that the soils cultivated with sugarcane in the states of Paraíba and Pernambuco posed available and reserve contents of micronutrients related to the parent materials and soil textural classes. The reserve contents of Fe, Mn, Zn, and Cu in all the soil samples analyzed were below the background values established for the region, which indicates a continuous exportation of micronutrients through cultivation. The mean and median contents of Mn, Zn, and Cu in diagnostic leaves of sugarcane were below their respective nutritional optimum ranges recommended to Brazil while Fe contents achieved the crop nutritional requirement. This is the first time such an approach based on pedogeological contexts is used to study the available and reserve pools of micronutrients in soils of Northeast Brazil.
  • Mitigation of Mombasa Grass ( Megathyrsus maximus ) Dependence on Nitrogen Fertilization as a Function of Inoculation with Azospirillum brasilense Division – Soil Use And Management

    Leite, Rubson da Costa; Santos, Antonio Clementino dos; Santos, José Geraldo Donizetti dos; Leite, Robson da Costa; Oliveira, Leonardo Bernardes Taverny de; Hungria, Mariangela

    Resumo em Inglês:

    ABSTRACT Using biological inputs to improve the efficiency of nitrogen fertilizers represents an alternative for the cultivation of grasses in tropical regions. Azospirillum brasilense is a species of plant growth promoting bacteria widely studied and used in inoculants. Thus, this study aimed to evaluate the performance of Mombasa grass ( Megathyrsus maximus ) in association with A. brasilense and nitrogen (N) fertilization. The study was conducted under field conditions in Araguaína-Tocantins State, between December 2017 and May 2018. The treatments were arranged in randomized blocks, in a 5 × 2 factorial arrangement, with five doses of N fertilization (0, 25, 50, 75, and 100 kg ha-1) combined with two inoculation treatments (inoculated and non inoculated), in four replicates. For the number of tillers and root production, the inoculation efficiency varied as a function of the supplied N doses. However, the percentage of leaf N was higher for inoculated plants regardless of the application of nitrogen. In the absence of nitrogen fertilization, it was possible to increase forage production by up to 36 % with inoculation.
  • Modeling of the Rainfall and R-Factor for Tocantins State, Brazil Division – Soil Use And Management

    Avanzi, Junior Cesar; Viola, Marcelo Ribeiro; Mello, Carlos Rogério de; Giongo, Marcos Vinicius; Pontes, Lucas Machado

    Resumo em Inglês:

    ABSTRACT The state of Tocantins is inserted in the new Brazilian agricultural frontier and has shown enormous potential for expansion of the agricultural lands. However, there is a lack of more elaborate scientific information for better planning and guide agricultural activities, especially regarding the soil and water conservation. Tocantins has a relevant rainfall spatial variability and, consequently, rainfall erosivity. Thus, this work aimed to develop models to estimate the mean monthly and annual rainfall and means rainfall erosivity factor (R-factor) of the Universal Soil Loss Equation (USLE) for the state of Tocantins. For that, 97 historical series of daily rainfall were studied, considering a standard period of 25 years (1985-2009). The fitting of the models adjustment datasets consists of 86 rain-gauges, out of which, 11 were randomly selected and used solely for model validation. Afterward, maps of these variables were generated based on the regression-kriging procedure. The fitted models presented precision statistical that allow characterizing them as “good quality”, with a coefficient of determination higher than 0.68 for rainfall models and 0.65 for the R-factor model, besides acceptable bias. Therefore, the application of the models can be successfully carried out, aiding the agricultural planning in the state of Tocantins.
  • Assessing Water Erosion Processes in Degraded Area Using Unmanned Aerial Vehicle Imagery Division – Soil Use And Management

    Siqueira Junior, Paulo; Silva, Marx Leandro Naves; Cândido, Bernardo Moreira; Avalos, Fabio Arnaldo Pomar; Batista, Pedro Velloso Gomes; Curi, Nilton; Lima, Wellington de; Quinton, John Norman

    Resumo em Inglês:

    ABSTRACT The use of Unmanned Aerial Vehicles (UAVs) and Structure from Motion (SfM) techniques can contribute to increase the accessibility, accuracy, and resolution of Digital Elevation Models (DEMs) used for soil erosion monitoring. This study aimed to evaluate the use of four DEMs obtained over a year to monitor erosion processes in an erosion-degraded area, with occurrence of rill and gully erosions, and its correlation with accumulated rainfall during the studied period. The DEMs of Geomorphic Change Detection (GCD) of horizontal and vertical resolutions of 0.10 and 0.06 m were obtained. It was possible to detect events of erosion and deposition volumes of the order of 2 m3, with a volumetric error of ∼50 %, in rills and gullies in the initial stage denominated R and GS-I, respectively. Events of the order of 100 m3, with a volumetric error around 14 % were found for advanced gullies, a segment denominated GS-II. In the three studied erosion situations, the deposition volume increased with the accumulated rainfall. The segments R and GS-I presented an inverse relationship between erosion volume and accumulated rainfall during the studied period. This behaviour can be explained by the dynamics of the deposition and erosion volumes during the erosion process. In the GS-II segment, erosion and deposition volumes were proportional and a direct relation with the cumulative rainfall over the studied period and a low percentage of volumetric error were found.
  • Errata: Stability of Soil Moisture Patterns Retrieved at Different Temporal Resolutions in a Tropical Watershed Errata

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