No-Tillage System Can Improve Soybean Grain Production More Than Conventional Tillage System.

Soil management systems can directly interfere with crop yield via changes in the soil's physical and hydraulic properties. However, short- to medium-term experiments of conduction do not always demonstrate the modifications of the management systems in these properties. Thus, the aim of this study was to evaluate the physical properties of the soil in a long-term management system and to relate it to the storage and availability of water to plants, verifying its effect on soybean yield. The experiment was conducted in randomized blocks in a split-plot scheme with four replications. Plots were composed by soil management (conventional tillage and no-tillage), and subplots represented three soil depths (0.0-0.1, 0.1-0.2, and 0.2-0.4 m). The soil's physical and hydraulic properties, root development, and soybean yield were evaluated. The no-tillage system not only presented higher bulk density and soil resistance to compaction up to a depth of 0.2 m but also greater root development. This management also did not affect the process of water infiltration in the soil and presented an increase in soybean grain yield by 6.5%. The long-term no-tillage system (33 years) offers less risk of water stress to soybean plants; it contributes to greater grain yield of this crop when compared to the conventional tillage system.

Soil-Plant Relationships in Soybean Cultivated under Crop Rotation after 17 Years of No-Tillage and Occasional Chiseling.

No-tillage cover crops contribute to better soil quality, being able to replace mechanized tillage management. This observation can only be made after several years of adopting conservationist practices and through research on soil-plant relationships. The objective of the research was to verify the relationship between the production components, physiological, root development, and physical-hydric properties of the soil in the yield of soybean grown in succession to different cover crops or with soil chiseling. The experiment was carried out in a randomized block design with four replications, comparing the cultivation of sunn hemp (Crotalaria juncea) and millet (Penninsetum glaucum L.) as cover crops and a treatment with soil chiseling. The evaluations were carried out during soybean (Glycine max L.) cultivation in the 2019/20 summer crop, that is, after 17 years of experimenting started in 2003. Rotation with sunn hemp increased soybean yield by 6% and 10%, compared with millet rotation and soil chiseling. The species used in crop rotation in a long-term no-tillage system interfere with the physical and water characteristics of the soil, affecting the physiological responses and soybean yield. The rotation with sunn hemp offers greater water stability to the plants and provides greater soybean yield in succession. Future research that better addresses year-to-year variation, architecture, and continuity of pores provided by crop rotation, and evaluations of gas exchange, fluorescence, and activities of stress enzymes in soybean plants may contribute to a better understanding of soil-plant relationships in long-term no-till.

Soil morphostructural characterization and coffee root distribution under agroforestry system with Hevea Brasiliensis

Land use and tillage practices may change soil structure and undermine sustainable agriculture; however, such changes are hardly identified in the short term. In this sense, agroforestry systems have been used to reduce soil degradation and promote sustainable production in coffee plantations. These areas are expected to have well-structured soils and hence improved root distribution. This study aimed to evaluate soil quality by the morphostructural and root distribution analyses comparing open-grown coffee and coffee in agroforestry systems with rubber trees for 19 years, in an Oxisol in northern Paraná State (Brazil). Treatments consisted of open-grown coffee (OG), coffee partially shaded by rubber trees (PSH), and coffee fully shaded by rubber trees (FSH). The mapping of morphostructural features and soil resistance to penetration in cultural profile walls identified changes in soil structure resulting from different tillage systems. Root distribution was better in coffee plants grown in PSH and FSH systems. At greater depths, cultural profiles of FSH and PSH showed a larger numbers of roots compared to OG. Among the three systems, PSH provided a better environment for root growth and distribution. This result could be attributed to the high biological activity and interaction between roots and aggregates in that profile. The FSH agroforestry system provided less compact morphological structures and more roots throughout the soil profile. The agroforestry systems presented fewer soil structural changes by tillage operations and lower values of soil penetration resistance. Coffee root distribution was an effective indicator of soil quality and consistent with the morphostructural characterization of cultural profile.(AU)

Soil morphostructural characterization and coffee root distribution under agroforestry system with Hevea Brasiliensis

Land use and tillage practices may change soil structure and undermine sustainable agriculture; however, such changes are hardly identified in the short term. In this sense, agroforestry systems have been used to reduce soil degradation and promote sustainable production in coffee plantations. These areas are expected to have well-structured soils and hence improved root distribution. This study aimed to evaluate soil quality by the morphostructural and root distribution analyses comparing open-grown coffee and coffee in agroforestry systems with rubber trees for 19 years, in an Oxisol in northern Paraná State (Brazil). Treatments consisted of open-grown coffee (OG), coffee partially shaded by rubber trees (PSH), and coffee fully shaded by rubber trees (FSH). The mapping of morphostructural features and soil resistance to penetration in cultural profile walls identified changes in soil structure resulting from different tillage systems. Root distribution was better in coffee plants grown in PSH and FSH systems. At greater depths, cultural profiles of FSH and PSH showed a larger numbers of roots compared to OG. Among the three systems, PSH provided a better environment for root growth and distribution. This result could be attributed to the high biological activity and interaction between roots and aggregates in that profile. The FSH agroforestry system provided less compact morphological structures and more roots throughout the soil profile. The agroforestry systems presented fewer soil structural changes by tillage operations and lower values of soil penetration resistance. Coffee root distribution was an effective indicator of soil quality and consistent with the morphostructural characterization of cultural profile.

Fractal features of soil texture and physical attributes in indian dark earth under different uses in Western Amazon / Características fractais da textura e atributos físicos do solo em áreas com terra preta de índio sob diferentes usos na Amazônia Ocidental

Studying particle size distribution is important to understand soil structure and formation processes. This research aimed to assess the fractal dimension of soil texture in Indian Dark Earth (IDE) areas in southern Amazonas state under different land uses, as follows: two areas in the municipality of Apuí, one growing cocoa and the other coffee; a grassland area in the municipality of Manicoré; and a forest area in the municipality of Novo Aripuanã. A sampling grid containing 88 collection points (intersecting points on the grid) was established in each area, measuring 80 x 42 m for the cocoa and coffee-growing sites, and 80 x 56 m and 60 x 42 m for the grassland and forest areas, respectively. Soil samples were collected in soil core and as clumps at a depth of 0.0-0.20m to determine the structural physical properties and texture of the soil. The following physical attributes were assessed: texture (PSD), bulk density (BD), macroporosity (Macro), microporosity (Micro), total porosity (TP) and aggregate stability (GMD and WMD). The fractal dimension (D) of the soil texture was determined, followed by analysis of variance and comparison of the means using Tukey's test (p≤0.05). Pearson's correlation was applied to assess the correlation between variables. There was a significant difference between the IDEs studied, with a higher D value in the cocoa-growing area in relation to the other sites. Additionally, the larger the clay fraction, the higher the D value. Fractal dimension (D) showed a positive correlation with sand, clay, BD, Macro, GMD and WMD, and a negative correlation with silt, micro, TP. Based on the D values obtained, the ADE cultivated with cocoa showed superior quality in relation to the other areas studied.KEYWORDS: Fractal dimension. Soil physics. Soil use. INTRODUCTION Applications of fractal geometry in soil science have shown that soil exhibits fractal characteristics, being a porous medium having different particle compositions, with irregular shape and self-similar structure (TYLER; WHEATCRAFT, 1989; KRAVCHENKO; ZHANG, 1998). Fractal geometry, proposed and established by Mandelbrot (1982), is a method for describing systems with non-characteristic scales and self-similarity. In recent years, this theory has been used to quantitatively describe the particle size distribution of soil, attracting the interest of pedologists worldwide (DENG et al., 2017). Particle size distribution is one of the most important physical characteristics of soil because of its significant influence on water flow and soil erosion (XU; LI; LI, 2013). In this respect, broad and precise knowledge of particle size distribution is vital to understanding soil structures and formation, since it is closely related to soil erosion, organic matter content and moisture content (DU et al., 2017). Deng et al. (2017) studied the fractal features of soil particle size distribution and found an association between fractal dimensions and the physical and chemical properties of the soil analyzed, indicating that the lower the fractal dimension, the worse the soil physical and chemical properties. Recently, the fractal method was applied to estimate soil structure and proved to be an efficient tool in analyzing soil Received: 01/04/2019 Accepted: 30/01/2020

Estudar a distribuição do tamanho das partículas é importante para entender a estrutura do solo e os processos de formação. Esta pesquisa teve como objetivo avaliar a dimensão fractal da textura do solo em áreas de Terra Preta de Índio (TPI) no sul do Estado do Amazonas sob diferentes usos da terra: duas áreas no município de Apuí, uma com cultivo de cacau e outra de café; uma área de pastagem no município de Manicoré; e uma área florestal no município de Novo Aripuanã. Uma malha de amostragem contendo 88 pontos de coleta (pontos de interseção na grade) foi estabelecida em cada área, medindo 80 x 42 m para as áreas de cacau e café, e 80 x 56 m e 60 x 42 m para as áreas de pastagem e floresta, respectivamente. Amostras de solo foram coletadas em torrões a uma profundidade de 0,0-0,20 m para determinar as propriedades físicas estruturais e a textura do solo. Os seguintes atributos físicos foram avaliados: textura, densidade do solo (DS), macroporosidade (Macro), microporosidade (Micro), porosidade total (PT) e estabilidade de agregados (DMG e DMP). Determinou-se a dimensão fractal da textura do solo (D), seguida da análise de variância e comparação das médias pelo teste de Tukey (p≤0,05). A correlação de Pearson foi aplicada para avaliar a correlação entre as variáveis. Houve uma diferença significativa entre as TPIs estudadas, com um maior valor D na área de cultivo de cacau em relação aos outros locais. Além disso, quanto maior a fração argila, maior o valor de D. A dimensão fractal (D) apresentou correlação positiva com areia, argila, DS, Macro, DMG e DMP, e correlação negativa com silte, micro, PT. Com base nos valores de D obtidos, as TPIs cultivadas com cacau apresentaram qualidade superior em relação às demais áreas estudadas.PALAVRAS-CHAVES: Dimensão Fractal. Física do solo. Uso do solo. REFERENCES ALVARENGA, R. C.; FERNANDES, B.; SILVA, T. C. A.; RESENDE, M. Estabilidade de agregados de um Latossolo Roxo sob diferentes métodos de preparo do solo e de manejo da palha do milho. Revista Brasileira de Ciência do Solo, Viçosa, v. 10, n. 2, p. 273-277, 1986.

Least limiting water range, S-index and compressibility of a Udalf under different management systems

Agricultural areas in the region of Turuçu, on the Southeast Hillside in the state of Rio Grande do Sul (RS), Brazil present many examples of soil physical degradation. Accordingly, strategies aimed at evaluating and ameliorating the structural quality of soils should be developed to ensure the sustainable use of these areas. This study aimed to evaluate the least limiting water range (LLWR), S-index, compressibility parameters, organic carbon and the organic matter granulometric fractions of a Udalf under different agricultural uses. Soil samples with disturbed and non-disturbed structure from the 0.00 to 0.10 m layer were collected on farms in the Southeast Hillside, Turuçu region, RS, for analyzing soil under: i) conventional system of corn after tobacco crop, (CT); ii) conventional system of corn after native field (CNF), iii) native field (NF) and iv) native area (NA). Both the CT and the CNF systems had a negative influence on the values of bulk density, soil porosity, least limiting water range, compressibility parameters and total organic carbon, coarse fraction carbon and carbon associated with minerals.(AU)

Least limiting water range, S-index and compressibility of a Udalf under different management systems

Agricultural areas in the region of Turuçu, on the Southeast Hillside in the state of Rio Grande do Sul (RS), Brazil present many examples of soil physical degradation. Accordingly, strategies aimed at evaluating and ameliorating the structural quality of soils should be developed to ensure the sustainable use of these areas. This study aimed to evaluate the least limiting water range (LLWR), S-index, compressibility parameters, organic carbon and the organic matter granulometric fractions of a Udalf under different agricultural uses. Soil samples with disturbed and non-disturbed structure from the 0.00 to 0.10 m layer were collected on farms in the Southeast Hillside, Turuçu region, RS, for analyzing soil under: i) conventional system of corn after tobacco crop, (CT); ii) conventional system of corn after native field (CNF), iii) native field (NF) and iv) native area (NA). Both the CT and the CNF systems had a negative influence on the values of bulk density, soil porosity, least limiting water range, compressibility parameters and total organic carbon, coarse fraction carbon and carbon associated with minerals.

Distribuição do tamanho de poros em um Latossolo Vermelho em sistema integrado de produção agropecuária / Distribution of size of pores in a Oxisolin an integrated system of agricultural production

Os sistemas integrados de produção agropecuária visam a sustentabilidade, procurando explorar o máximo da área, além de diminuir os impactos sobre as propriedades do solo. O presente trabalho teve objetivo estudar a distribuição do tamanho de poros de um Latossolo Vermelho em um sistema integrado de produção agropecuária após três anos de implantação do sistema. O experimento foi realizado na Fazenda pertencente ao grupo Facholi, no município de Caiuá/SP. O delineamento experimental utilizado foi em blocos casualizados, com três repetições e compostos por 7 tratamentos: 1 - Soja–Milho + B. ruziziensis (pastejo); 2 - Soja Milho + Piatã (pastejo); 3 - Soja Milho + Paiaguás (pastejo); 4 - Soja - Piatã (pastejo 2 anos) Soja - Piatã (pastejo); 5 - Soja - Paiaguás (pastejo 2 anos) Soja - Paiaguás (pastejo); 6 -Soja milho (Plantio direto); 7 - Soja milho (Preparo convencional). Foram realizadas as avaliações dos seguintes atributos do solo: macroporosidade, microporosidade, porosidade total e densidade do solo, em duas camadas do solo; 0,00-0,10 e 0,10-0,20 m de profundidade, em três épocas de coleta, utilizando o teste Tukey a 5% de probabilidade para a comparação de médias. Os resultados mostram que a macroporosidade aumentou com o tempo (3 anos de avaliação), e houve uma diminuição da densidade do solo, mostrando que os sistemas avaliados influenciaram positivamente os atributos do solo estudados. De forma geral, todos ao tratamentos aumentaram a macroporosidade em relação a caracterização inicial, com destaque para os tratamentos soja+piatã e soja+milho+piatã, camada de 0-0,10m que obtiveram valores médios superiores aos demais.(AU)

Integrated agricultural production systems aim at sustainability, seeking to exploit the maximum of the area, as well as reducing impacts on soil properties. The objective of this work was to study the distribution of pore size of an Oxisol in an integrated agricultural production system after three years of system implantation. The experiment was carried out at Fazenda belonging to the Facholi group, in the municipality of Caiuá / SP. The experimental design was a randomized complete block with three replicates and composed of 7 treatments: 1 - Soya - Maize + B. ruziziensis (grazing); 2 - Soybean - Maize + Piatã (grazing); 3 -Soya - Maize + Paiaguás (grazing); 4 - Soya - Piatã (grazing 2 years) - Soya - Piatã (grazing); 5 - Soybean - Paiaguás (grazing 2 years) - Soybean - Paiaguás (grazing); 6 - Soybean - maize (Direct planting); 7 - Soybean - corn (Conventional preparation). The following soil attributes were evaluated: macroporosity, microporosity, total porosity and soil density in two depths of soil; 0.00-0.10 and 0.10-0.20 m depth, in three sampling periods, using the Tukey test at 5% probability for the comparison of means. The results show that the macroporosity increased with time(3 years of evaluation), and there was a decrease in soil density, showing that the evaluated systems positively influenced the soil attributes studied. In general, all treatments increased the macroporosity in relation to the initial characterization, especially the soybean + piatan and soy + maize + piatã treatments, 0-0.10 m depth, which obtained higher, average values than the others.(AU)

Distribuição do tamanho de poros em um Latossolo Vermelho em sistema integrado de produção agropecuária / Distribution of size of pores in a Oxisolin an integrated system of agricultural production

Os sistemas integrados de produção agropecuária visam a sustentabilidade, procurando explorar o máximo da área, além de diminuir os impactos sobre as propriedades do solo. O presente trabalho teve objetivo estudar a distribuição do tamanho de poros de um Latossolo Vermelho em um sistema integrado de produção agropecuária após três anos de implantação do sistema. O experimento foi realizado na Fazenda pertencente ao grupo Facholi, no município de Caiuá/SP. O delineamento experimental utilizado foi em blocos casualizados, com três repetições e compostos por 7 tratamentos: 1 - Soja–Milho + B. ruziziensis (pastejo); 2 - Soja – Milho + Piatã (pastejo); 3 - Soja – Milho + Paiaguás (pastejo); 4 - Soja - Piatã (pastejo 2 anos) – Soja - Piatã (pastejo); 5 - Soja - Paiaguás (pastejo 2 anos) – Soja - Paiaguás (pastejo); 6 -Soja – milho (Plantio direto); 7 - Soja – milho (Preparo convencional). Foram realizadas as avaliações dos seguintes atributos do solo: macroporosidade, microporosidade, porosidade total e densidade do solo, em duas camadas do solo; 0,00-0,10 e 0,10-0,20 m de profundidade, em três épocas de coleta, utilizando o teste Tukey a 5% de probabilidade para a comparação de médias. Os resultados mostram que a macroporosidade aumentou com o tempo (3 anos de avaliação), e houve uma diminuição da densidade do solo, mostrando que os sistemas avaliados influenciaram positivamente os atributos do solo estudados. De forma geral, todos ao tratamentos aumentaram a macroporosidade em relação a caracterização inicial, com destaque para os tratamentos soja+piatã e soja+milho+piatã, camada de 0-0,10m que obtiveram valores médios superiores aos demais.

Integrated agricultural production systems aim at sustainability, seeking to exploit the maximum of the area, as well as reducing impacts on soil properties. The objective of this work was to study the distribution of pore size of an Oxisol in an integrated agricultural production system after three years of system implantation. The experiment was carried out at Fazenda belonging to the Facholi group, in the municipality of Caiuá / SP. The experimental design was a randomized complete block with three replicates and composed of 7 treatments: 1 - Soya - Maize + B. ruziziensis (grazing); 2 - Soybean - Maize + Piatã (grazing); 3 -Soya - Maize + Paiaguás (grazing); 4 - Soya - Piatã (grazing 2 years) - Soya - Piatã (grazing); 5 - Soybean - Paiaguás (grazing 2 years) - Soybean - Paiaguás (grazing); 6 - Soybean - maize (Direct planting); 7 - Soybean - corn (Conventional preparation). The following soil attributes were evaluated: macroporosity, microporosity, total porosity and soil density in two depths of soil; 0.00-0.10 and 0.10-0.20 m depth, in three sampling periods, using the Tukey test at 5% probability for the comparison of means. The results show that the macroporosity increased with time(3 years of evaluation), and there was a decrease in soil density, showing that the evaluated systems positively influenced the soil attributes studied. In general, all treatments increased the macroporosity in relation to the initial characterization, especially the soybean + piatan and soy + maize + piatã treatments, 0-0.10 m depth, which obtained higher, average values than the others.

Direct seeding with different furrow openers: changes in properties of a South Brazilian latosol (oxisol) and crop yields / Semeadura direta com diferentes mecanismos sulcadores: alterações em propriedades de um Latossolo Bruno e produtividade das culturas

The mechanisms of seeding machines to cut the mulch, mobilize the topsoil and deposit the seeds in the furrows modify soil properties and interfere in crop growth. This study sought to evaluate the effects of furrow openers and scarification on the attributes of a South Brazilian latosol (Bruno oxisol) and crop yields. The treatments were: double disc furrow opener (DD); shovel type furrow opener (S); shoe type furrow opener (SH); and scarification followed by double disc furrow opener (SC+DD). Samples were collected at 0-10, 10-20 and 20-40 cm and evaluated for soil physical (bulk density, total porosity, macro and microporosity), chemical (pH, Ca, Mg, K and P) and organic carbon content. The normality of data was tested, and the analysis of the variance was performed (F test, p 0.05), and the means was compared by Tukeys test (p=0.05). Soil attributes were analyzed for each layer separately. After four years it was observed that the bulk density is still affected by scarification, which reduces it. The successive use of DD in the winter for the implantation of the crops caused the homogenization of the soil, although with no differences on the other physical and chemical properties. In general, grain yield and dry mass were higher in the treatment that used scarification and the double disc during the summer, and the shoe type when compared to shovel type.(AU)

Os mecanismos das semeadoras para cortar os resíduos vegetais, mobilizar a camada superficial do solo e depositar as sementes nos sulcos modificam os atributos do solo e interferem no crescimento das culturas. Portanto, comparar os efeitos destes mecanismos é necessário. Este estudo objetivou avaliar o efeito de diferentes mecanismos sulcadores de semeadora-adubadoras, e da escarificação, sobre atributos de um Latossolo Bruno alumínico típico, e na produtividade de culturas. Os tratamentos avaliados foram: sulcadores tipo disco duplo (DD); sulcadores tipo guilhotina (GUI); sulcadores tipo facão (FA); e escarificação seguido de disco duplo (ESC+DD). Amostras de solo foram coletadas nas camadas de 0-10, 10-20 e 20-40 cm para avaliar atributos físicos (densidade, porosidade total, macro e microporosidade), químicos (pH, Ca, Mg, K e P) e conteúdo de carbono orgânico. Avaliou-se a matéria seca da parte aérea da soja e a produtividade das culturas em três safras distintas. Foi testada a normalidade dos dados, e realizada a análise da variância (teste F a p 0,05), e apresentando significância as médias foram comparadas pelo teste de Tukey a 5%. Os atributos de solo foram analisados para cada camada separadamente. Após quatro anos observou-se que a densidade do solo ainda é afetada pela escarificação, que a reduziu. A utilização sucessiva de DD no inverno para a implantação das culturas provocou homogeneização do solo, não diferindo as demais propriedades físicas e químicas. De maneira geral a produtividade de grãos e massa seca foram superiores no tratamento onde houve escarificação, utilização do disco duplo no verão e utilização do facão, em comparação a guilhotina.(AU)

Direct seeding with different furrow openers: changes in properties of a South Brazilian latosol (oxisol) and crop yields / Semeadura direta com diferentes mecanismos sulcadores: alterações em propriedades de um Latossolo Bruno e produtividade das culturas

The mechanisms of seeding machines to cut the mulch, mobilize the topsoil and deposit the seeds in the furrows modify soil properties and interfere in crop growth. This study sought to evaluate the effects of furrow openers and scarification on the attributes of a South Brazilian latosol (Bruno oxisol) and crop yields. The treatments were: double disc furrow opener (DD); shovel type furrow opener (S); shoe type furrow opener (SH); and scarification followed by double disc furrow opener (SC+DD). Samples were collected at 0-10, 10-20 and 20-40 cm and evaluated for soil physical (bulk density, total porosity, macro and microporosity), chemical (pH, Ca, Mg, K and P) and organic carbon content. The normality of data was tested, and the analysis of the variance was performed (F test, p 0.05), and the means was compared by Tukeys test (p=0.05). Soil attributes were analyzed for each layer separately. After four years it was observed that the bulk density is still affected by scarification, which reduces it. The successive use of DD in the winter for the implantation of the crops caused the homogenization of the soil, although with no differences on the other physical and chemical properties. In general, grain yield and dry mass were higher in the treatment that used scarification and the double disc during the summer, and the shoe type when compared to shovel type.

Os mecanismos das semeadoras para cortar os resíduos vegetais, mobilizar a camada superficial do solo e depositar as sementes nos sulcos modificam os atributos do solo e interferem no crescimento das culturas. Portanto, comparar os efeitos destes mecanismos é necessário. Este estudo objetivou avaliar o efeito de diferentes mecanismos sulcadores de semeadora-adubadoras, e da escarificação, sobre atributos de um Latossolo Bruno alumínico típico, e na produtividade de culturas. Os tratamentos avaliados foram: sulcadores tipo disco duplo (DD); sulcadores tipo guilhotina (GUI); sulcadores tipo facão (FA); e escarificação seguido de disco duplo (ESC+DD). Amostras de solo foram coletadas nas camadas de 0-10, 10-20 e 20-40 cm para avaliar atributos físicos (densidade, porosidade total, macro e microporosidade), químicos (pH, Ca, Mg, K e P) e conteúdo de carbono orgânico. Avaliou-se a matéria seca da parte aérea da soja e a produtividade das culturas em três safras distintas. Foi testada a normalidade dos dados, e realizada a análise da variância (teste F a p 0,05), e apresentando significância as médias foram comparadas pelo teste de Tukey a 5%. Os atributos de solo foram analisados para cada camada separadamente. Após quatro anos observou-se que a densidade do solo ainda é afetada pela escarificação, que a reduziu. A utilização sucessiva de DD no inverno para a implantação das culturas provocou homogeneização do solo, não diferindo as demais propriedades físicas e químicas. De maneira geral a produtividade de grãos e massa seca foram superiores no tratamento onde houve escarificação, utilização do disco duplo no verão e utilização do facão, em comparação a guilhotina.

Spatial and temporal variability of soil electrical conductivity related to soil moisture

Soil electrical conductivity (ECa) is a soil quality indicator associated to attributes interesting to site-specific soil management such as soil moisture and texture. Soil ECa provides information that helps guide soil management decisions, so we performed spatial evaluation of soil moisture in two experimental fields in two consecutive years and modeled its influence on soil ECa. Soil ECa, moisture and clay content were evaluated by statistical, geostatistical and regression analyses. Semivariogram models, adjusted for soil moisture, had strong spatial dependence, but the relationship between soil moisture and soil ECa was obtained only in one of the experimental fields, where soil moisture and clay content range was higher. In this same field, coefficients of determinations between soil moisture and clay content were above 0.70. In the second field, the low soil moisture and clay content range explain the absence of a relationship between soil ECa and soil moisture. Data repetition over the years, suggested that ECa is a qualitative indicator in areas with high spatial variability in soil texture.

Spatial and temporal variability of soil electrical conductivity related to soil moisture

Soil electrical conductivity (ECa) is a soil quality indicator associated to attributes interesting to site-specific soil management such as soil moisture and texture. Soil ECa provides information that helps guide soil management decisions, so we performed spatial evaluation of soil moisture in two experimental fields in two consecutive years and modeled its influence on soil ECa. Soil ECa, moisture and clay content were evaluated by statistical, geostatistical and regression analyses. Semivariogram models, adjusted for soil moisture, had strong spatial dependence, but the relationship between soil moisture and soil ECa was obtained only in one of the experimental fields, where soil moisture and clay content range was higher. In this same field, coefficients of determinations between soil moisture and clay content were above 0.70. In the second field, the low soil moisture and clay content range explain the absence of a relationship between soil ECa and soil moisture. Data repetition over the years, suggested that ECa is a qualitative indicator in areas with high spatial variability in soil texture.

Physical quality of the trails at the state park Cerrado PR / Qualidade física do solo das trilhas do parque estadual do Cerrado PR

The tourism in protected areas has been gaining attention and interest. However, the increased flow of people in these areas may endanger the ecological integrity of these environments preserved since the intensification of tourist crossing the tracks may enhance the possibility of soil compaction (soil degradation). This study aims to evaluate the effect of the movement of people in some soil physical properties of the State Park trails Cerrado (PR) to guide future actions in planning the use and occupation of the area that contribute to the preservation of the ecosystem. To evaluate the physical soil were collected at random points, 5 soil samples off track (FTr) and track (Tr) with preserved structure in the depth of 0-20 cm. With these samples, we determined the bulk density, total porosity, macro and micro, organic matter and aggregate stability. The trails of the state park Cerrado (PR) receiving more than 50 visitors over the month, showed no degradation as the organic matter content and soil aggregation in relation to the area of native soil.

A atividade turística em unidades de conservação vem ganhando interesse e destaque. Contudo, o aumento do fluxo de pessoas nestas áreas pode colocar em risco a integridade ecológica desses ambientes preservados, pois, a intensificação da passagem de turistas nas trilhas pode acentuar a possibilidade de compactação do solo (degradação do solo). O presente trabalho tem por objetivo avaliar o efeito do trânsito de pessoas em alguns atributos físicos do solo das trilhas do Parque Estadual do Cerrado (PR), a fim orientar futuras ações de planejamento do uso e ocupação da área que concorram para preservação do ecossistema. Para a avaliação física do solo foram coletadas em pontos aleatórios, 5 amostras de solo fora da trilha (FTr) e na trilha (Tr) com estrutura preservada na profundidade de 0-20 cm. Com essas amostras, determinou-se a densidade do solo, a porosidade total, a macro e microporosidade, a matéria orgânica e a estabilidade de agregados. As trilhas do parque estadual do Cerrado (PR) que recebem mais de 50 visitantes ao longo do mês, apresentaram degradação em relação à densidade e porosidade do solo, e não apresentaram degradação quanto ao teor de matéria orgânica e agregação do solo em relação á área de solo nativo.

Physical quality of the trails at the state park Cerrado PR / Qualidade física do solo das trilhas do parque estadual do Cerrado PR

The tourism in protected areas has been gaining attention and interest. However, the increased flow of people in these areas may endanger the ecological integrity of these environments preserved since the intensification of tourist crossing the tracks may enhance the possibility of soil compaction (soil degradation). This study aims to evaluate the effect of the movement of people in some soil physical properties of the State Park trails Cerrado (PR) to guide future actions in planning the use and occupation of the area that contribute to the preservation of the ecosystem. To evaluate the physical soil were collected at random points, 5 soil samples off track (FTr) and track (Tr) with preserved structure in the depth of 0-20 cm. With these samples, we determined the bulk density, total porosity, macro and micro, organic matter and aggregate stability. The trails of the state park Cerrado (PR) receiving more than 50 visitors over the month, showed no degradation as the organic matter content and soil aggregation in relation to the area of native soil.

A atividade turística em unidades de conservação vem ganhando interesse e destaque. Contudo, o aumento do fluxo de pessoas nestas áreas pode colocar em risco a integridade ecológica desses ambientes preservados, pois, a intensificação da passagem de turistas nas trilhas pode acentuar a possibilidade de compactação do solo (degradação do solo). O presente trabalho tem por objetivo avaliar o efeito do trânsito de pessoas em alguns atributos físicos do solo das trilhas do Parque Estadual do Cerrado (PR), a fim orientar futuras ações de planejamento do uso e ocupação da área que concorram para preservação do ecossistema. Para a avaliação física do solo foram coletadas em pontos aleatórios, 5 amostras de solo fora da trilha (FTr) e na trilha (Tr) com estrutura preservada na profundidade de 0-20 cm. Com essas amostras, determinou-se a densidade do solo, a porosidade total, a macro e microporosidade, a matéria orgânica e a estabilidade de agregados. As trilhas do parque estadual do Cerrado (PR) que recebem mais de 50 visitantes ao longo do mês, apresentaram degradação em relação à densidade e porosidade do solo, e não apresentaram degradação quanto ao teor de matéria orgânica e agregação do solo em relação á área de solo nativo.

Índice s no diagnóstico da qualidade estrutural de latossolo muito argiloso sob manejo intensivo / S index in structural quality diagnostic of a very clayey oxisol under intense management

Neste estudo foi verificada a adequação de uso do índice S no diagnóstico da qualidade estrutural de um Latossolo Vermelho distrófico de cerrado cultivado com cafeeiro sob sistema de manejo que adota a aplicação de altas doses de gesso na linha da cultura, cultivo e manejo mecanizado de braquiária na entrelinha da cultura, além de preparo do sulco de plantio até 60 cm de profundidade, dentre outras técnicas de manejo intensivo. O índice S foi correlacionado à densidade e à porosidade do solo nas profundidades de 5, 20, 40 e 80 cm, na linha do cafeeiro, e 5, 10, 20, 40, 65 cm na entrelinha do cafeeiro. Para a determinação do índice S nas diferentes profundidades e locais de amostragem foram construídas curvas de retenção de água, sendo utilizadas amostras com estrutura preservada. Os valores deste atributo físico foram superiores a 0,045 indicando ótima qualidade física do solo sob o sistema de manejo adotado. Houve boa correlação entre o índice S com os atributos físicos analisados, mostrando ser esta uma boa ferramenta a ser utilizada no diagnóstico da qualidade estrutural do solo.

In this study we verified the adequacy of use of the Dexter S index in the diagnosis of structural quality of a Cerrado Oxisol cultivated with coffee in management system that adopts the application of high doses of gypsum in row culture, mechanized cultivation and management of Brachiaria in the interrows, and preparation of the furrow 60 cm deep, among other techniques of intensive management. The S was correlated with the density and porosity of the soil at depths of 5, 20, 40 and 80 cm along the row of coffee, and 5, 10, 20, 40, 65 cm between rows of coffee. For the determination of the S at different depths and sampling sites were built water retention curves, using samples with structure preserved. The values of this physical attribute were greater than 0.045 indicating good soil physical quality under the management system adopted. There was good correlation between the S with the physical attributes analyzed, showing that this is a good tool to use in the diagnosis of structural soil quality.

Soil physical properties in Royal Gala apple orchards under conventional and organic production systems / Atributos físicos do solo em pomares de maçãs Royal Gala em sistemas convencional e orgânico de produção

The management of apple orchards is conditioned by the form of cultivation adopted, which influences on plant yield, profitability and longevity of the area. This study aimed to evaluate the effects of management systems for conventional and organic apple production on soil physical properties and identify the variables that discriminate between the two production systems, using canonical discriminant analysis (CDA). The experiment was carried out in São Joaquim, SC, in two orchards, one under conventional system (CS) and the other under organic system (OS), both established in 2001, using Royal Gala cultivar, on M9 rootstock, in a Humic Cambisol. Soil samples were collected during 2008-2009 season in the layers 0-10 cm and 10-20 cm. The soil physical properties evaluated were particle size distribution, aggregate stability, represented by the mean geometric diameter (MGD), bulk density (BD), total porosity (TP) and degree of flocculation (DF). The results were tested for comparison of means and CDA. The OS had higher values of MGD and BD in the two layers. In the 10-20 cm layer, macroporosity was greater in the CS. The MGD in the layer 0-10 cm and microporosity in the layer 10-20 cm showed the highest values of parallel discrimination rate coefficient (PDRC), revealing that these properties were good indicators of soil physical quality and can be used to study changes in apple

O manejo dos pomares de maçãs é condicionado pela forma de cultivo adotado, o qual influencia na sua produtividade, lucratividade e longevidade. O presente estudo teve como objetivo avaliar os efeitos dos sistemas de manejo convencional e orgânico de produção de maçãs sobre atributos físicos do solo e identifi car os parâmetros que discriminam os dois sistemas de produção, por meio da utilização da análise canônica discriminante (ACD). O experimento foi realizado no município de São Joaquim, SC, em dois pomares, um no sistema convencional (PC) e o outro no sistema orgânico (PO), ambos implantados em 2001, com a cultivar Royal Gala, sobre porta-enxerto M-9, em um Cambissolo Húmico. As amostras de solo foram coletadas na safra 2008-2009, nas camadas de 0-10 cm e 10-20 cm. Os atributos físicos do solo avaliados foram granulometria, estabilidade de agregados, representada pelo diâmetro médio geométrico (DMG), densidade do solo (Ds), macro, micro e porosidade total (PT) e grau de floculação (GF). Os resultados obtidos foram submetidos ao teste de Tukey para comparação de médias e à ACD. O PO apresentou menores valores de DMG e macroporosidade na camada de 0-10 cm. Na camada de 10-20 cm, a macroporosidade e PT foram maiores no PC. O DMG na camada de 0-10 cm e a microporosidade na camada de 10-20 cm apresentaram os maiores valores de coeficientes de taxa de discriminação paralela (TDP

Soil physical properties in Royal Gala apple orchards under conventional and organic production systems / Atributos físicos do solo em pomares de maçãs Royal Gala em sistemas convencional e orgânico de produção

The management of apple orchards is conditioned by the form of cultivation adopted, which influences on plant yield, profitability and longevity of the area. This study aimed to evaluate the effects of management systems for conventional and organic apple production on soil physical properties and identify the variables that discriminate between the two production systems, using canonical discriminant analysis (CDA). The experiment was carried out in São Joaquim, SC, in two orchards, one under conventional system (CS) and the other under organic system (OS), both established in 2001, using Royal Gala cultivar, on M9 rootstock, in a Humic Cambisol. Soil samples were collected during 2008-2009 season in the layers 0-10 cm and 10-20 cm. The soil physical properties evaluated were particle size distribution, aggregate stability, represented by the mean geometric diameter (MGD), bulk density (BD), total porosity (TP) and degree of flocculation (DF). The results were tested for comparison of means and CDA. The OS had higher values of MGD and BD in the two layers. In the 10-20 cm layer, macroporosity was greater in the CS. The MGD in the layer 0-10 cm and microporosity in the layer 10-20 cm showed the highest values of parallel discrimination rate coefficient (PDRC), revealing that these properties were good indicators of soil physical quality and can be used to study changes in apple

O manejo dos pomares de maçãs é condicionado pela forma de cultivo adotado, o qual influencia na sua produtividade, lucratividade e longevidade. O presente estudo teve como objetivo avaliar os efeitos dos sistemas de manejo convencional e orgânico de produção de maçãs sobre atributos físicos do solo e identifi car os parâmetros que discriminam os dois sistemas de produção, por meio da utilização da análise canônica discriminante (ACD). O experimento foi realizado no município de São Joaquim, SC, em dois pomares, um no sistema convencional (PC) e o outro no sistema orgânico (PO), ambos implantados em 2001, com a cultivar Royal Gala, sobre porta-enxerto M-9, em um Cambissolo Húmico. As amostras de solo foram coletadas na safra 2008-2009, nas camadas de 0-10 cm e 10-20 cm. Os atributos físicos do solo avaliados foram granulometria, estabilidade de agregados, representada pelo diâmetro médio geométrico (DMG), densidade do solo (Ds), macro, micro e porosidade total (PT) e grau de floculação (GF). Os resultados obtidos foram submetidos ao teste de Tukey para comparação de médias e à ACD. O PO apresentou menores valores de DMG e macroporosidade na camada de 0-10 cm. Na camada de 10-20 cm, a macroporosidade e PT foram maiores no PC. O DMG na camada de 0-10 cm e a microporosidade na camada de 10-20 cm apresentaram os maiores valores de coeficientes de taxa de discriminação paralela (TDP

Adjustment of the expedite method for clay content determination in Rondônia soils / Ajuste de método expedito para determinação de teor de argila em solos de Rondônia

Soil clay content is an important soil attribute and has been used to classification of phosphorus status in the soil in order to determinate the needing of phosphorus amounts to be applied to crops production. The aim of this research was to adjust the method for soil clay content determination, adopted by the laboratories of Southern Brazil (ROLAS-RS/SC), for soil clay content evaluation in Rondônia soils. The study was conducted using 50 soil samples from Rondônia State with wide range clay content. It was tested shaking periods (1.5, 2.0 and 2.5h) associated with periods for soil particles decantation (1.5 and 2.0h) to correlate with the standard method for soil texture testing, known as the pipette method. Clay content determined through this method was significantly correlated with pipette method. The better treatment was the combination of 2.0h of shaking and 1.5h of decantation, resulted in total period of 3.5h, which reduced the period to determine the soil clay content without loss of accuracy.

O teor de argila é um importante atributo de solo e é utilizado na determinação de faixas de teores de fósforo para fins de recomendação de adubação. O objetivo deste trabalho foi ajustar o método de determinação de argila utilizado pelos laboratórios da ROLAS-RS/SC para avaliar os teores de argila dos solos de Rondônia. O estudo foi conduzido com 50 amostras de solos do Estado de Rondônia, com diferentes teores de argila. O teor de argila foi determinado utilizando-se o método da ROLAS-RS/SC, com diferentes períodos de agitação (1,5; 2,0 e 2,5h) e de decantação das partículas do solo (1,5 e 2,0h) e o método da pipeta, considerado padrão para essa determinação. Os teores de argila determinados nas combinações de períodos de agitação e de decantação se correlacionaram significativamente com os teores determinados pelo método da pipeta. O melhor tratamento foi a combinação de 2,0h de agitação e 1,5h de decantação, resultando em tempo total de 3,5h, que reduz o tempo para determinação do teor de argila do solo sem perda significativa da eficiência.

Chemical migration during soil water retention curve evaluation

Wetting and drying (W-D) cycles can induce important elemental migrations in soils. The main purpose of this work was to study the possible existence of soil chemical elemental migrations in samples submitted to repeated W-D cycles during evaluations of soil water retention curve (SWRC). The experimental measurements were carried out by Atomic Absorption Spectrometry (AAS) for Ca2+, Mg2+ and K+ on samples of three different Brazilian tropical soils (Geric Ferralsol, Eutric Nitosol and Rhodic Ferralsol). Results demonstrate an increase in the electrical conductivity of the water extracted from the samples and significant losses of Ca2+, Mg2+ and K+ during the applications of up to nine W-D cycles. It was also observed differences in SWRC for all soils when samples submitted to the application of several W-D cycles were compared with samples not submitted to it. These differences occurred at the region of both structural and textural pores. A possible explanation for these results could be the soil chemical migration during the sequences of W-D cycles, which can affect the soil structure development.

Os ciclos de umedecimento e secamento (U-S) podem induzir importantes migrações de elementos químicos no solo. O objetivo principal deste trabalho foi estudar a possível existência de migração de elementos químicos em amostras de solos submetidas a repetidos ciclos de U-S durante a avaliação da curva de retenção de água do solo. As determinações de Ca2+,Mg2+ e K+ foram obtidas por Espectrometria de Absorção Atômica em três diferentes solos tropicais do Brasil (Latossolo Vermelho-Amarelo, Nitossolo Vermelho e Latossolo Vermelho). Os resultados demonstram um aumento da condutividade elétrica da água extraída das amostras de solo e perda significativa de Ca2+, Mg2+ e K+ após a aplicação de nove ciclos de U-S. Diferenças nas curvas de retenção foram também observadas para todos os solos quando as amostras submetidas aos ciclos de U-S foram comparadas com as amostras não submetidas. Essas diferenças ocorreram tanto na região estrutural quanto textural dos poros do solo. Uma possível explicação para esses resultados pode ser a migração de elementos químicos do solo durante as sequências de ciclos de U-S, os quais podem afetar o desenvolvimento da estrutura do solo.