Sum Of Bases Research Articles

Oxisol subsurface chemical attributes related to sugarcane productivity

In spite of the great homogeneity found in the morphological characteristics of Oxisols, there is great chemical diversity in subsurface layers of these soils. Studies indicate that crop yield presents significant correlation with the chemical attributes of the subsurface, which, are more stable than attributes found in the plough layer, subject to greater alterations as a consequence of agricultural exploration. This work evaluated the effects of subsurface chemical attributes of Oxisols of the South Central region of Brazil, on the yield of sugarcane clones and of variety RB72454, during the first, second and third cropping cycles. Productivity data were obtained between 1993 and 1998. Soils were characterized in terms of their mechanical analysis and chemical traits at 0.8 to 1.0 m; correlation studies between these attributes and mean daily productivity as well as multiple regression analysis were also carried out; variables were selected based on their R² values by means of the stepwise procedure. The subsurface chemical traits of the Oxisols influenced sugarcane productivity, especially the 3rd harvest; the clone productivity model for the 3rd harvest as a function of base saturation and phosphorus content presented R² = 0.31, i.e., 31% of the variation in sugarcane yield (t ha-1 day-1) can be explained by these two attributes. For variety RB72454, 47% of that variation is explained by the sum of bases and contents of calcium and organic matter. Variations on productivity at 1st and 2nd harvests can be better explained by pHwater.

Removal of Cu and Zn from swine raising wastewater using organic filters

Rice husks, coffee bean skins, sugar cane bagasse, maize cobs, saw dust and fine charcoal dust were evaluated as filters for the removal of heavy metals (Cu and Zn) from the waste water of swine raising installations. The specific mass, pH and the sum of bases and removable adds were determined to characterize each of the filter materials. Each filtering material was placed in a 100 mm diameter, 600 mm long, PVC column to a height of 500 mm under 12,500 N m‐2 of compression. Chemical and physical analyses were determined on effluent samples collected for each 1.5 l. up to a total of 15 l. The organic materials reduced the concentration of sediment solids (>90%), total solids (up to 33%) and Cu (up to 43.6%) of the inffluent but had little or no effect on Zn concentration.

Efeito de formas de manejo em algumas propriedades físicas e químicas de um Latossolo Vermelho em diferentes agroecossistemas

Foram selecionadas, em 1998, quatro áreas de um Latossolo Vermelho Eutrófico típico muito argiloso, uma sob mata nativa (Floresta Latifoliada Tropical) e três sob cultivo de milho, cana-de-açúcar e pastagem, localizadas na Fazenda de Ensino e Pesquisa da Faculdade de Ciências Agrárias e Veterinárias, Campus de Jaboticabal. Caracterizaram-se as seguintes propriedades físicas: resistência do solo à penetração, realizada com penetrômetro de impacto, até 40 cm de profundidade e velocidade de infiltração de água, realizada com o duplo cilindro concêntrico, nos quatro sistemas de uso do solo. Foram realizadas determinações analíticas de fósforo, matéria orgânica, pH, cálcio, magnésio, potássio, hidrogênio + alumínio e calculados a soma de bases, CTC e saturação por bases. Todas as formas de uso e manejo empregadas provocaram degradação das propriedades físicas do solo em relação ao solo natural (mata), quantificada através de maiores valores de resistência do solo à penetração e menores valores de velocidade de infiltração de água. A degradação das propriedades químicas dos solos nos agroecossistemas estudados foi maior nas culturas de cana-de-açúcar e milho, que na pastagem. A degradação das propriedades físicas causou ao solo níveis críticos mais limitantes ao desenvolvimento das culturas, que aqueles referentes às propriedades químicas.

Spatial heterogeneity of soil properties in areas under elephant-grass short-duration grazing system

Soil properties can be changed by several factors, such as plant roots and animal trampling. The identification of spatial heterogeneity of these properties depends on the sampling scale. This study was developed to test the hypothesis that soil chemical and physical properties beneath elephant-grass plants are different from those between them. The research was carried out in a soil classified as Kandiudalfic Eutrudox. Forty-eight soil samples were collected from 0-10 cm depth (24 beneath plants and 24 between plants). The following properties were measured: pH, organic matter, S, available P, K, Ca and Mg exchangeable, sum of bases, cation exchange capacity, base saturation percentage, dry-aggregate distribution, bulk density and soil penetration resistance. Statistical analyses (t test) indicated that there were no significant differences in soil chemical properties in relation to spatial position. However, significant differences were observed in soil physical properties, with higher values of bulk density and soil resistance to penetration between the plants than beneath the plants.

Effect of two types of lime on some soil physical attributes of an oxisol from Brazil

Liming is a very important practice, especially in acid soils such as some Oxisols from Brazil, in which the chemical effects of liming are reasonably known. However, the effects of liming on soil physical properties are either not well known or, at least, controversial. In order to verify, under field conditions, the effect of liming on some soil physical attributes such us the aggregate stability, the water dispersible clay, the water retention were evaluated in a citrus liming experiment on a Dark Red Latosol (Typic Haplorthox) clay texture, from Cordeirópolis, São Paulo State, Brazil. The soil samples were collected in 0–10 cm and 10–20 cm depths, three years after the application of lime in the experiment, which had two replications per treatment. Calcitic and dolomitic limes were used with application rates of 0, 3, and 9 Mg ha‐1, with a total of five treatments, i.e., one control and two rates of application of each kind of lime. The results showed an increase in the aggregate stability. As a consequence, a significant linear correlation was found between aggregate mean weighted diameter (MWD) and calcium content and other indices affected by liming such as pH, sum of bases, base saturation and aluminum content. An increase in the stability indices (MWD) resulted in an increase in the water retained at 0.03 MPa and 0.1 MPa.

Large area spatial variability of soil chemical properties in central Brazil

Understanding the spatial distribution pattern of soil properties is important to determine soil constraints to plant nutrition and appropriate management of soil resources in recently cultivated areas. This study addresses spatial variability of exchangeable potassium (K e) and sum of bases ( S B) in Mato Grosso State, Brazil. Geostatistical methods described the spatial variability and predicted along four transects crossing different soil mapping units and land use types. Ordinary kriging appropriately estimates values in unsampled areas. It identifies places where more intensive sampling is required. This study shows that land use affected spatial variability of K e and S B in well-defined structural patterns. In particular, K e exhibits a strong spatial dependence and anisotropy in two horizons. Traditional surveys of soil fertility, together with data from soil survey maps, can be used in combination with geostatistics by decision-makers to support management planning and to predict indicators related to soil quality as a measure of sustainability. As it turns out, K e and S B need to be sampled at different densities, and soil survey information can be used to advantage to reduce the sampling efforts of S B by 96%.

Eficiência de cordões de pedra em contorno na retenção de sedimentos e melhoramento de propriedades de um solo litólico

Em face de suas características de moderada a alta erodibilidade e pequena profundidade efetiva, os solos litólicos requerem eficientes práticas conservacionistas no sentido de protegerem sua estreita camada arável, que é ameaçada por altas taxas de erosão em regiões semi-áridas do Estado do Ceará. Conhecem-se bem as conseqüências da erosão nesses solos, porém são escassas as pesquisas sobre os efeitos, a longo prazo, das práticas conservacionistas sobre a intensidade de perdas de solo, bem como sobre o melhoramento de suas propriedades. Treze anos após a construção de cordões de pedra em contorno, a massa de sedimentos retida e as mudanças que esta prática de controle da erosão induziu nas características químicas, físicas e topográficas de um solo litólico foram avaliadas. O experimento foi executado em Quixadá (CE), de março a julho de 1994. Sob declive de 0,03 mm-1, essa prática conservacionista reteve uma média de 60 t ha-1 ano-1 de sedimentos em camadas de até 0,30 m de espessura ao longo das barreiras de pedra. As deposições, provocadas por esses obstáculos às enxurradas, formaram, progressivamente, patamares pelo nivelamento natural da superfície original do terreno. Essa prática conservacionista induziu expressivos melhoramentos na qualidade do solo relacionados à elevação dos seguintes parâmetros: profundidade efetiva, porosidade, água disponível, matéria orgânica, nitrogênio, soma de bases, saturação de bases e capacidade de troca de cátions; por outro lado, verificou-se um decréscimo de alumínio nas camadas de sedimentos retidos pelos cordões de pedra, ao longo dos treze anos de controle da erosão.

VARIABILIDADE ESPACIAL DE ARGILA, SILTE E ATRIBUTOS QUÍMICOS EM UMA PARCELA EXPERIMENTAL DE UM LATOSSOLO ROXO DE CAMPINAS (SP)

A grande maioria dos ensaios de manejo e fertilidade do solo utiliza o método de delineamentos experimentais, segundo o qual as observações devem ser independentes umas das outras e as parcelas experimentais, uniformes quanto aos atributos estudados. A hipótese de independência entre as amostras apenas pode ser satisfeita e verificada na prática, se a amostragem contiver informações geográficas, como, por exemplo, as coordenadas com referências a um eixo arbitrário para possibilitar análises da geoestatística. O objetivo deste trabalho foi estudar a variabilidade espacial de alguns atributos químicos e granulométricos do solo dentro de uma parcela experimental e mostrar o uso da geoestatística para analisar os dados. O campo estudado localiza-se no Centro Experimental de Campinas do Instituto Agronômico, Campinas (SP), em um latossolo roxo distrófico sob preparo convencional nos últimos dez anos. Marcou-se uma parcela de 30 m por 30 m a cada 5 m em duas direções, resultando em um reticulado quadrado de 49 pontos de amostragem. Em cada ponto, coletaram-se amostras de solo das camadas 0-25 cm e 25-50 cm de profundidade, as quais foram levadas ao laboratório, secas ao ar, peneiradas em uma malha de 2 mm e submetidas às análises granulométricas e químicas de rotina para obter teor de argila, teor de silte, delta pH, soma de bases (S), capacidade de troca catiônica (CTC) e saturação por bases (V%). Para a análise de variabilidade espacial, utilizou-se a geoestatística. Os coeficientes de variação encontrados são mais altos na camada 0-25 cm do que na 25-50 cm, provavelmente devido à região de maior alteração com cultivo. Foi encontrada dependência espacial para todos os atributos analisados para a camada 0-25 cm, e dependência fraca para a camada 25-50 cm. Considerando que o campo engloba apenas uma área de 30 m por 30 m, conclui-se que a variabilidade encontrada para os atributos químicos do solo foi grande e que a amostragem ao acaso falharia em detectá-la e, por isso, esconderia a realidade.

The content and distribution of cadmium in soils as influenced by the soil properties

The total and soluble cadmium contents of 29 natural, uncultured, unpolluted soils from the province of Salamanca (Spain) were determined. The two forms of the metal were found to occur at concentrations over the ranges 0.07-0.33 and 0.004-0.061 μg/g, respectively. The total Cd contents found were somewhat low relative to reported values for worldwide soils in general and European soils in particular. No significant correlation was found between the total and soluble Cd contents or between the former and any chemical parameters of the soils. On the other hand, there was a highly significant correlation ( P < 0.001) between soluble Cd and the pH, sum of bases and exchangeable Ca, as well as a significant correlation ( P < 0.01) between soluble Cd and the cation exchange capacity, degree of saturation and exchangeable Mg content of the soils. Finally, there were virtually no similarities in the distribution patterns of Cd and the other soil parameters in a given soil profile.

Relationships between soil properties and vegetation at the Northern Experimental Forest, Howland, Maine

This research relates the results of a survey and detailed analysis of soils in a northern mixed conifer forest to vegetation characteristics as represented by remotely sensed data. The work was conducted at International Paper's Northern Experimental Forest (NEF) at Howland, Maine as part of NASA's Forest Ecosystem Dynamics (FED) project. An intensive soil survey was performed and relationships between soil properties (i.e., drainage class, depth of active zone, water holding capacity, carbon / nitrogen ratio, pH, and sum of bases), species composition, and normalized difference vegetation index (NDVI) from the Advanced Visible and Infrared Imaging Spectrometer (AVIRIS) were derived. Results showed that there was great variability in soil properties across the landscape due to complex regional glacial activity and recent alluvial events. Significant statistical differences were observed in species composition and NDVI between soil mapping units and with soil drainage class. However, other specific soil properties could not be used to explain these differences given the number of soil samples characterized, or without taking disturbance and management history into account. Simulation modeling, which would include soil data and stand history information as inputs, would provide an additional means of interpreting the relationship between remotely sensed imagery, inferred ecosystem properties, and complex, landscape-level patterns of soil characteristics.

Adsorption and Mobility of Cadmium in Natural, Uncultivated Soils

AbstractThe influence of soil properties on the adsorption and mobility of Cd was studied in 22 natural, uncultivated soils from Salamanca province to understand the environmental characteristics of Cd as a pollutant. Cadmium adsorption was studied by means of adsorption isotherms, using low Cd concentrations that were similar to those potentially found in polluted soils, and Cd mobility was investigated by using soil thin layer chromatography. The Freundlich adsorption constant (K) was not found to be related to any soil properties studied. In contrast, the distribution coefficients (Kd) at 15 and 30 µg L−1 equilibrium concentrations were found to be related to the cation exchange capacity (CEC) of the soil (r = 0.43 and r = 0.44, respectively, p &lt; 0.05). The adsorption (Q), amount adsorbed at high concentrations (Ci = 1000/µg L−1), was found to be significantly related to the CEC, the exchangeable Ca2+ content and the sum of bases. In addition, Rf values, which are indicative of the Cd mobility in soil, bore a highly significant (p &lt; 0.001) negative correlation with some soil parameters such as pH, the exchangeable Ca2+ and Mg2+ contents and the sum of bases, as well as a less significant (p &lt; 0.05), negative correlation with the CEC and clay content of the soil, but no correlation whatsoever with the adsorption constants. The type of organic matter present in the soil must be more influential on Cd mobility than was its content. The above results confirm that a CEC of a soil is highly influential on Cd adsorption and mobility.

Mobility of cadmium as influenced by soil properties, studied by soil thin-layer chromatography

We studied the mobility of cadmium in various natural soils by soil thin-layer chromatography. The R F values of the soils varied between 0.14 and 1.00 (mean = 0.64, mode = 0.87). Cadmium was found to be slightly mobile in 27%, moderately mobile in 14%, mobile in 41% and highly mobile in 18% of the soils studied. A statistical analysis of the results obtained revealed a highly significant correlation ( p < 0.001) between R F values and pH, the sum of bases and the exchangeable Ca 2+ and Mg 2+ contents, as well as a significant negative correlation ( p < 0.05) between R F and the clay content and cation-exchange capacity of the soils. The results show the significance of soil properties to the mobility of cadmium wastes from industrial, mining and farming applications.

Humus degradation under the influence of simulated ?acid rain?

The purpose of these investigations was to describe changes occurring in soil under the influence of simulated ‘acid rains’. It was achieved by treating three kinds of soil with water solutions of pH: 2.0, 3.0, 4.0, 5.0, 6.0, 7.8 for two vegetation periods. Differences were found in the pH of soils reaching 2.5 values in the sorption complex. The content of H+ increased and the sum of bases considerably decreased. Significant changes in number of bacteria, fungi, macromycetes were found. In most acid solutions they decreased by 100% as compared with the reference surface. The processes of nitrification, cellulose decomposition and soil respiration were limited, whereas ammonification was stimulated. Under the influence of ‘acid rains’ the content of C and N remained unchanged, while the content both of fulvic and grey and brown humic acids was reduced. With the increase in soil acidity the content of hymatomelanic acids increased. So significant changes in the content of bitumen, humins, humic C and the Q4/6 color quotient were observed under the influence of simulated ‘acid rains’.

Effects of deep ploughing and superficial disc harrowing on physical and chemical soil properties and biomass in a new plantation of Eucalyptus globulus

A field trial was carried out of Portugal on a plantation of Eucalyptus globulus Labill. to compare the effects of minimal (surface disc harrowing) and intensive (deep ploughing) site preparation techniques on various soil properties as well as on biomass production. The results presented cover the first 30 months after planting. Disc harrowing resulted in a significant decrease in bulk density to 30-cm depth, a decrease in soil compaction to 10-cm depth and an increase in aeration porosity in the 0 to 10-cm layer. Deep ploughing induced a decrease in the bulk density between 10- and 80-cm depth, but had no effect on the aeration porosity or the levels of soil compaction. The rate of water infiltration was higher in the former than in the latter type of treatment. In both treatments the chemical properties of the soil were only affected within the top 20 cm. Significant decreases in organic carbon, pH, exchangeable Ca, sum of bases and cation exchange capacity occurred in both treatments. Decreases in all variables except pH were significantly higher in deep ploughed than in disc-harrowed plots. i.e. where the organic matter was concentrated. Biomass production and partitioning, measured 18 and 30 months after planting, were not affected by the treatments. However, roots were concentrated in the 0 to 20-cm layer in the disc-harrowed plots and in the 20 to 75-cm layer in the deep-ploughed plots. The results are discussed with references to currently applied silvicultural techniques for managing E. globulus plantations in Portugal.

Alternative use of the SMP‐buffer solution to determine lime requirement of soils

Abstract A close relationship was found between the pH of soil suspensions in the SMP buffer solution (pHsmp) and the potential acidity of soils (H + Al) extracted by a neutral calcium acetate solution (r = 0.98), for twenty six soil samples of the State of Sao Paulo, Brazil, This relationship was represented by the equation lnY = 7.76 ‐ 1.053X, which allowed for the calculation of H + Al directly from the values of pHsmp. With the values of H + Al and the sum of bases, calcium, magnesium and potassium, the cation exchange capacity (CEC), and the base saturation (V) were calculated. Relationships between the base saturation of the soils and the active acidity of soil suspensions were close, both for pH determined in water (r=0.94) and pH determined in 0.01M CaCl2 solution (r ‐ 0.97). Thus the lime requirement (LR) of soils could be calculated, for given values of pH or base saturation, using the equation LR = CEC (V2 ‐ V1)/100, in which V1 is the base saturation of the soil and V2 is the expected value up...

Variability of Measured Properties in Morphologically Matched Pedons

AbstractVariability in data from morphologically matched pairs of pedons was assessed to establish operational norms in sampling and to consider alternative sampling procedures.Coefficients of Variation (C.V.'s) were computed for the physical properties—percent sand, silt, clay, and 1,500 kPa moisture—and range from 9 to 40% for loess, 23 to 35% for glacial drift, 33 to 47% for alluvium and residuum, 18 to 32% for A and B horizons, and 33 to 51% for C horizons. C.V.'s were computed for the chemical properties—extractable acidity, sum of bases, cation exchange capacity (CEC), base saturation, pH, and organic carbon—and range from 12 to 50% for Alfisols, 4 to 71% for Aridisols, 6 to 61% for Entisols, 10 to 63% for Inceptisols, 9 to 46% for Mollisols, 16 to 132% for Spodosols, 10 to 100% for Ultisols, and 8 to 46% for Vertisols. Cation exchange C.V.'s are directly related to pH dependent charge.On the average, clay content for central concepts of phases of series can be estimated within ± 5% clay (95% confidence level) by 1 to 4 samples in loess soils, 2 to 8 samples in glacial drift soils, and 4 to 24 samples in alluvial and residual soils.Similar estimates of base saturation (sum of cations) within ± 10% (95% confidence level) require 2 samples for Aridisols and Vertisols; 5 for Mollisols; 10 for Alfisols, Ultisols, Entisols, and Inceptisols; and 16 for Spodosols.Vertical distribution of properties and properties of important horizons are efficiently evaluated by sampling one complete pedon plus satellite samples of important horizons from other pedons. To assess a single horizons efficiently, sample only that horizon in several pedons. Sampling of paired pedons is a good first approach technique to study soils in an area.

Adsorption of Copper and Lead by Ap and B2 Horizons of Several Northeastern United States Soils

AbstractAdsorption of Cu and Pb by surface and subsurface samples of fifteen soils was ascertained. Soil adsorption maxima were derived from the reciprocal of the slope obtained by a least squares fit of “Langmuir” plots for each soil. The adsorption maxima were then regressed against various chemical and mineralogical properties of the soils in an attempt to deduce mechanisms of adsorption as well as to determine whether any commonly measured soil quantity could serve as a predictor of adsorption. The best predictor of adsorption by all samples was sum of bases, which explained 84 and 76% of the variation in Cu and Pb adsorption, respectively. In the subsurface horizons, the adsorption of both Cu and Pb was significantly related to vermiculite content (r2 = 0.78 and 0.85, respectively), but sum of bases was still a better prediction for these horizons alone (r2 = 0.83 and 0.92, respectively). Organic matter content had no significant relationship to adsorption by surface horizons.

Effects of social support on adherence to therapeutic regimens: Retha V. Wellons, Institute of Social Research, RCGD, University of Michigan, Ann Arbor, MI, 48106; Robert D. Caplan, R. Van Harrison, John R. P. French, Jr.

A soil fertility index map (SFIm) can provide key information to decision-makers in regard to spatial planning in the context of sustainable land management. The establishment of such SFIm requires basic soil properties that can be modelled for spatial mapping. The objective of this study was to take advantage of Benin soil legacy data to produce a digital SFIm at a national level based on 8 soil properties (soil organic matter, nitrogen, pH (water), exchangeable potassium, assimilable phosphorus, sum of bases, cation exchange capacity and base saturation). Specific research aims were (1) to model and develop digital soil maps, (2) to identify the key covariates influencing soil nutrients, and (3) to build an SFIm using digital maps of the soil properties. For each soil property, modelling procedures involved the use of different covariates, including soil type, topographic, bioclimatic and spectral data, along with the comparative assessment of the cubist (CB) and quantile random forest (QRF) models. Models were evaluated not only on the basis of classical error metrics (RMSE, R2) but also on the ability to predict local uncertainty based on the prediction interval coverage probability (PICP). The results revealed that CB performed marginally better than the QRF based on classical error metrics (R2, RMSE) but produced the worst uncertainty with an overestimation of the local uncertainty. This suggested that the use of accuracy plots such as PICP to evaluate models can identify accuracy problems not evident with classical error metrics. The analysis revealed that the distance to the nearest stream, which was part of topographic covariates, had strong predictive ability for all the soil properties along with the bioclimatic variables. The spatial distribution of the different classes of SFIm showed a preponderance of low fertility levels with severe limitations for crop development. A limited number of high and average fertility level soils were found in the low elevation areas of southern Benin, and policy could advocate for their sole use for agricultural purposes and promote sustainable management practices.

Levantamento pedológico detalhado da estação experimental de Ribeirão Preto, SP

O presente trabalho descreve o levantamento de solos, ao nível de série, efetuado na Estação Experimental de Ribeirão Preto, SP, a qual ocupa uma área de 594 ha. O relevo regional é dominado por superfícies suavizadas, colinosas, entre as quais sobressaem testemunhos tabuliformes; o tipo climático segundo o sistema de Köppen é o Aw, o material de origem é proveniente de basalto e a vegetação primitiva era predominantemente a mata latifoliada tropical. Em trincheiras de 60 x 60 x 60 cm, complementadas por tradagens em sua base e em barrancos de estradas, foram observados e descritos 361 pontos, dos quais em 174 foi coletado material para análise granulométrica e/ou química. Além desses pontos coletaram-se e descreveram-se nove perfis. Foram estabelecidas nove unidades taxonômicas pertencentes aos grandes grupos: Eutrortox, Haplortox, Umbriortox, Tropudalf e Eutropept e ainda dois complexos indiscriminados. Tomando por base o valor da saturação em bases (V%) do horizonte óxico superior ou inferior a 50, subdividiu-se o grande grupo Eutrortox em duas classes. Considerando os valores de soma de bases (S) e de saturação em bases (V%) do epipedon, subdividiram-se as várias classes de solos pertencentes à subordem Ortox em fases, obtendo-se na legenda geral um total de 24 unidades de mapeamento.

Características analíticas dos agregados dos solos terra-roxa (latossolo roxo) e massapé (podzólico vermelho amarelo-orto)

Os resultados de laboratório mostram que o solo massapé contém maior quantidade de agregados grosseiros, de maior estabilidade nágua, do que a terra-roxa, confirmando as descrições de campo dêsses dois solos. As características físicas e químicas (textura, umidade, pH, matéria orgânica, N, bases trocáveis, capacidade de troca e óxidos livres de ferro), determinadas em todos os tamanhos de agregados dêsses solos, mostraram que: a)na terra roxa os valores dessas características, exceção feita dos óxidos livres de ferro, são mais elevados nos agregados maiores, e menores e mais baixos nos intermediários; os teores de óxidos livres de ferro parecem variam em função inversa dos teores de argila e matéria orgânica; b) no massapé observou-se que os valores das características analisadas eram praticamente os mesmos em tôdas as classes de tamanho de agregados; c) há uma relação nítida entre os valores de argila, matéria orgânica, soma de bases e capacidade de troca em tôdas as classes de tamanho de agregados. Os autores discutem a influência que os diversos elementos analisados podem ter sôbre as características estruturais dêsses solos.