Milton César Costa Campos

Dependência espacial da resistência do solo à penetração e do teor de água do solo sob cultivo contínuo de cana-de-açúcar

The intensive cultivation of soil and the use of machines and equipment promote soil compaction. Soil penetration resistance is a measure that detects this compaction, nevertheless soil moisture influences hardly on soil penetration resistance. The objective of this work was to evaluate the effect of soil moisture on the spatial variability of soil penetration resistance of an Oxisol. An area cultivated for 40 years with sugarcane was sampled in the crossing points of a regular grid, with 10 m intervals, comprising 100 points. Soil samples were collected at 0.00-0.15m, 0.15-0.30m and 0.30-0.45m depths, 24 and 72 hours after a 38mm precipitation. Soil penetration resistance values indicated that compaction was high at the two sampling periods. Soil moisture influenced the spatial variability of soil penetration resistance and a smaller spatial dependence was related to higher soil moistures. The grid used for the evaluation of soil penetration resistance variability must be closer than the one used for this study when the soil moisture is higher than the moisture observed 72 hours after the precipitation.

Topossequência de solos na transição campos naturais-floresta na região de Humaitá, Amazonas

The objective of this work was to study soil-relief relations in a grassland-forest transition, in the region of Humaita, Amazonas State, Brazil. The study area was selected based on the criterion of regional representativity (most common landscape) and in the level of environmental preservation. The sample collection was carried out in a transect from the grassland towards the forest, and the different soil environments were identified and limited according relief position, vegetation patterns and soil characteristics. Soil profiles were morphologically characterized and samples collected from all horizons for physical and chemical analysis for normal profile characterization. including SiO2, Al2O3 and Fe2O3 extracted by H2SO4 attack, free iron oxides by DCB extraction and poor crystalline iron oxides extracted by ammonium oxalate. Mineralogical analysis was also carried out by X-ray diffraction. The results suggest that soil variation in the landscape was directly related with the relief, which determines soil drainage and water table level.

Variabilidade espacial de atributos físicos em um cambissolo háplico, sob diferentes usos na região sul do Amazonas

Considering the importance of knowledge of the spatial distribution of soil properties, the purpose of this study was to evaluate the spatial variability of physical properties in a Cambisolunder different land uses in the southern Amazon region. The study was conducted on three farms with cassava, sugarcane, and agroforestry, in the region of Humaita, in the south of the State of Amazonas. In these areas, 70 x 70 m grids were established, with a regular spacing of 10 x 10 m and a total of 64 points, where soils were sampled at 0.0-0.10 m depth. Texture (sand, silt, and clay), macroporosity, microporosity, total porosity, bulk density, and aggregate stabilitywere determined. The data were analyzed using descriptive statistics and geostatistics. It was found that the propertiesvaried spatially and that the range of these variations between land uses was different, with the highest variability for the sugarcane management.

Relações solo-superfície geomórfica em uma topossequência várzea-terra firme na região de Humaitá (AM)

The geomorphic surface concept allows interrelationship among various branches of soil sciences, such as geology, geomorphology and pedology. The purpose of this study was to investigate soil-geomorphic surface relations along an upland-downland toposequence in the region of Humaita, Amazonas State, Brazil. A transect of 4,500 m was studied from the water divide downstream to the flood plain of the Madeira river. The geomorphic surfaces were identified based on the slope rupture, stratigraphic criteria and on other field observations. Trenches were dug in the identified slope segments, the soils were morphologically characterized and samples collected from each horizon. The physical properties particle size distribution, water dispersible clay and flocculation degree, soil and particle density, total porosity, and saturated hydraulic conductivity were determined. Chemical analysis involved pH in water and KCl; exchangeable Ca, Mg, K, Na, and Al; available P, Al + H and organic C; total SiO2, Al2O3 and Fe2O3 by sulfuric acid digestion; free iron oxides extracted with dithionite-citrate-bicarbonate and poor crystalline iron oxides with ammonium acid oxalate. The values of ∆pH, silt/clay, Ki and Fed/Fet ratio indicated more weathered soils at the top of the landscape, than along the infiltration slope, convex slope and alluvial footslope, coinciding with the older age of the soils of the geomorphic surface I than of II and III. The soil variations in the studied transect were related to the surface age, parent material and slope gradient. The understanding of the geomorphic events was important to explain the variation of soil properties in the toposequence.

Caracterização mineralógica de Latossolos em diferentes feições do relevo na região de Jaboticabal, SP

Resumo - As diferentes feicoes da superficie terrestre, expressas pelo relevo, sao capazes de provocar variacoes nos atributos do solo em magnitudes diferenciadas, dependentes, principalmente, de um local especifico da paisagem. Sendo assim, o objetivo deste trabalho foi realizar a caracterizacao mineralogica de Latossolos em diferentes feicoes do relevo na regiao de Jaboticabal, SP. Foram abertas tres trincheiras nas pedoformas convexa, linear e concava e, em seguida, foram realizadas a descricao morfologica dos horizontes e coleta de solo para caracterizacao fisica, quimica e mineralogica. Constatou-se que a mineralogia oxidica e dependente do tipo de pedoforma, com dominância de goethita na pedoforma concava e a hematita dominou em pedoforma linear. Os minerais da fracao argila desferrificada exibiram dominio de gibbsita na pedoforma concava, em comparacao as pedoformas convexas e lineares que predominam a mineralogia caulinitica. Palavras-chave - Forma da paisagem. Pedogenese. Mineralogia do solo.

Caracterização de terras pretas arqueológicas no sul do estado do Amazonas

The Archaeological Dark Earth (ADE) soils are characterized by its high fertility, dark color, and presence of pottery fragments. Regarding the formation of ADE, the most widely accepted hypothesis is that anthropogenic processes involving pre-Columbian populations made them. The purpose of this study is to characterize ADE units located in the Southern Amazon Region, in the cities of Apui and Manicore. Seven ADE sites were selected, trenches opened and the soil profiles characterized morphologically. Then, samples of each horizon were collected for analyses of the following physical and chemical properties: particle size, water-dispersible clay, flocculation, soil bulk density, particle density, total porosity, pH in water and KCl solutions, Ca2+, Mg2+, K+, Al3+, available P, H+Al, and organic C. Also, total oxides, free oxides and amorphous forms were analyzed. The texture of the anthropic A horizon ranged from sandy loam to clay loam. The pottery fragments and lithic material were found in similar quantities and at similar depths in the A horizons of the studied soil profiles, suggesting some similarity between the anthropogenic factors of formation. The anthropic horizons of profiles P3, P4, and P7 had a eutrophic character and high to very high levels of available phosphorus, compared to P1, P2, P5, and P6, indicating the heterogeneity of the ADEs.

Caracterização e classificação de terras pretas arqueológicas na Região do Médio Rio Madeira

Although several studies have been published about the Archaeological Dark Earths, few of them tried to understand and elucidate questions about the pedogenesis and behavior of these soils. Thus, the objective of this study was to characterize and classify Archaeological Dark Earths in four sites, selected in the region of the Middle Madeira River. Four pedons were morphologically characterized and collected for chemical, physical and mineralogical analysis. Physical analysis involved par- ticle size distribution, water dispersible clay, soil bulk and particle density, total porosity and saturated hydraulic conductivity. Chemical analysis involved pH in water and KCl, exchangeable cations, exchangeable aluminum, available P, extractable acid- ity (Al+H), organic carbon and, SiO 2 , Al 2 O 3 and Fe 2 O 3 extracted with H 2 SO 4 . Free iron oxides were extracted with dithionite- citrate-bicarbonate and poor crystalline iron oxides were extracted using ammonium acid oxalate. Mineralogical analysis of sand, silt and clay fractions were carried out by X-ray diffraction. The studied soils were classified in the Brazilian System of Soil Classification as Red Yellow Argisol, Gray Argisol and Yellow Argisol. The presence of the anthropogenic A horizons with similar chemical properties and depths in all studied sites suggests that similar conditions have influenced their formation. All anthropogenic horizons studied in the region showed high base saturation and high to very high P availability as compared to subjacent horizons. The inclusion of the anthropogenic subgroup in the Brazilian System of Soil Classification was also suggested.

Geoestatística na avaliação dos atributos físicos em latossolo sob floresta nativa e pastagem na Região de Manicoré, Amazonas

A utilizacao das tecnicas geoestatisticas permite detectar a existencia da dependencia e distribuicao espacial dos atributos do solo, constituindo importante ferramenta na analise e descricao detalhada do comportamento dos atributos fisicos do solo. Este trabalho teve como objetivo o uso da geoestatistica na avaliacao dos atributos fisicos em Latossolo sob floresta nativa e pastagem na regiao de Manicore no Amazonas. Nas areas de floresta nativa e pastagem, foram estabelecidas malhas com dimensao 70 × 70 m e demarcados pontos nessas malhas espacados a cada 10 m, totalizando 64 pontos. Esses pontos foram georreferenciados e, em seguida, foram feitas as coletadas de solo em cada ponto da malha nas camadas de 0,00-0,20 e 0,40-0,60 m para determinacao dos atributos fisicos, totalizando 128 amostras de solo em cada malha. Essas malhas encontram-se paralelas com uma distância uma da outra de 100 m e o solo nessas areas e classificado como Latossolo. Determinaram-se textura, densidade do solo e de particulas, macroporosidade, microporosidade, porosidade total e estabilidade dos agregados em agua. Apos a tabulacao dos dados, foram realizadas analises estatisticas descritivas e geoestatistica. A pastagem apresentou leve variacao nos seus atributos fisicos em relacao a floresta nativa, com coeficiente de variacao alto e dependencia espacial fraca. Os semivariogramas escalonados conseguiram reproduzir de forma satisfatoria o comportamento espacial dos atributos no mesmo padrao dos semivariogramas individuais, e o uso do parâmetro alcance do semivariograma mostrou-se eficiente para determinar a densidade amostral ideal para os ambientes em estudo. Os resultados geoestatisticos indicaram que a retirada da floresta nativa para a implantacao da pastagem alterou a variabilidade natural dos atributos fisicos.

Aplicação de adubo e corretivo após o corte da cana-planta utilizando técnicas geoestatísticas

Knowing the spatial variation of soil properties can contribute for planning and optimization of experiments and commercial crops based on precision agriculture. The objective of this research was to evaluate the necessity of fertilizer and limestone applications for the implantation of precision agriculture techniques based on the spatial behavior of chemical attributes of one Latosol after the harvest of the sugarcane. The data were evaluated by means of descriptive statistics and spatial dependence analysis with the adjustment of semivariograms. The geostatistics techniques applied were found to be suitable as auxiliary tools in the fertilizer application by means of variable rates. It was detected that phosphorus and limestone applications were not necessary according to the variable rate.

Discrimination of geomorphic surfaces with multivariate analysis of soil attributes in sandstone - basalt lithosequence

The geomorphic surface concept allows interrelationship among various branches of soil sciences, such as geology, geomorphology and pedology. This association enhances the understanding of spatial soil distribution through landscape, pointing out the soil attributes behavior, which are mainly related to stratigraphy and relief forms. Therefore, this study aims to apply multivariate statistics to categorize geomorphic surfaces in sandstone - basalt lithosequence, so as to provide a basis for soil assessment in similar areas. The study area is located in Pereira Barreto County, SP, Brazil. An area of 530 hectare was selected, where three geomorphic surfaces (I, II and III) were located and mapped. In this area, 134 soil samples were collected at depths of 0.0-0.2 m and 0.8-1.0 m below ground surface. Sand, silt and clay contents were determined, pH in CaCl2 solution, OM, P, Ca, Mg, K, Al and H+Al contents were also evaluated. Based on the results, univariate, multivariate analysis of variance, cluster and principal-component analysis were performed in order to compare the three geomorphic surfaces. The univariate statistical analysis of soil attributes was not efficient enough to categorize the three geomorphic surfaces. By using the physical and chemical soil properties, the multivariate statistical techniques enabled the differentiation of the three groups of soil natural bodies which were equivalent to the same three mapped geomorphic surfaces (GS). These results are interestingin order to demonstrate the feasibility of the numerical classification use on geomorphic surfaces to assist the soil mapping.