Controlled traffic and soil physical quality of an Oxisol under sugarcane cultivation
Scientia Agricola, 2015
ABSTRACT Machinery traffic in sugarcane (Saccharumsp.) plantations reduces soil physical quality,... more ABSTRACT Machinery traffic in sugarcane (Saccharumsp.) plantations reduces soil physical quality, and hinders both root development and crop yield. We evaluated the physical quality of an Oxisol and the development of sugarcane roots under controlled traffic. The treatments assessed were: without controlled machinery traffic (WCT), controlled traffic by adjusting the tractor and infield wagons to a 3.0 m track width with the operator guiding the machinery (CT1) and the previous treatment using real time kinematic / global positioning system (RTK / GPS) precision auto steer (CT2). Soil samples were collected from the planting rows, seedbed and inter-row center to determine the least limiting water range (LLWR) and soil porosity from scanned 2-D images. The root dry mass was sampled from monoliths, separated from the soil by washing through a 2-mm sieve and dried in an oven. A higher LLWR was observed in the planting row under CT1 and CT2 than under WCT. The planting row had a predominance of complex pores with a diameter > 500 µm in the 0.15-0.27 m depth layer under CT1 and CT2. In the planting rows under WCT, the root dry mass was only 44 % of that measured under CT2. Benefits regarding soil physical quality and growth roots were observed when the tractor-wagon track width was adjusted based on the sugarcane spacing using either precision auto steering or manual operation of the machinery.
Qualidade física do solo em uma parcela permanente sob floresta ombrófila densa
... ombrófila densa CARLOS EDUARDO PINTO JUHÁSZ(1), JOSÉ EDUARDO SORIA(2), MIGUEL COOPER(3), RAUL... more ... ombrófila densa CARLOS EDUARDO PINTO JUHÁSZ(1), JOSÉ EDUARDO SORIA(2), MIGUEL COOPER(3), RAUL SHISO TOMA(4), ALINE ROBERTA DE CARVALHO(5) ... Referências [1] RODRIGUES, RR & GANDOLFI, S. 1998. ...
Soil characterization and discrimination on a topo-sequence over diabase through their reflected energy Caractérisation des sols d’une toposéquence sur diabase au moyen de leur réflectance spectrale
The Quality of the Brazilian Agrarian Reform Settlement Projects
An extensive field survey was conducted during the second semester of 2002, interview-ing 14,414 ... more An extensive field survey was conducted during the second semester of 2002, interview-ing 14,414 persons in 4,430 agrarian reform settlement projects, established during 1985 and 2001 in the entire Brazilian territory. These settlements cover an area of 241,980 km2 where ...
Evolução temporal do comportamento físico-hídrico do solo de um sistema agroflorestal no Vale do Ribeira–SP Temporal evolution of soil hydro-physical behavior of an agroforestry system on Ribeira Valley–SP
Soil micromorphology and its relation with physical and hydrical attributes
ABSTRACT The objective of this work was to evaluate the relationship between soil micromorphologi... more ABSTRACT The objective of this work was to evaluate the relationship between soil micromorphological and physical attributes in an Oxisol (Rhodic Eutrudox) under sugarcane. Soil samples were collected at the intersection points of a regular grid, with 10 m intervals, comprising a total of 100 points, in the horizons A1 and AB. The higher values for bulk density, microporosity and soil penetration resistance and lower values for macroporosity, total porosity and saturated hydraulic conductivity mainly in the AB horizon, indicated compaction in this horizon, confirmed by image analysis ( micromorphology).
Soil genesis and classification in the environment" mar de morros" in the mid-valley of the river Paraiba do Sul, RJ
Solos tropicais são geralmente considerados altamente intemperizados, o que é atribuído às condiç... more Solos tropicais são geralmente considerados altamente intemperizados, o que é atribuído às condições climáticas de altas temperaturas e precipitação pluvial. Entretanto, no ambiente de Mar de Morros, a intensidade dos processos pedogenéticos pode ser alterada pela ...
Evaluation of physical quality indices of a soil under a seasonal semideciduous forest
The concept of soil quality is currently the subject of great discussion due to the interaction o... more The concept of soil quality is currently the subject of great discussion due to the interaction of soil with the environment (soil-plant-atmosphere) and practices of human intervention. However, concepts of soil quality relate quality to agricultural productivity, but assessment of soil quality in an agronomic context may be different from its assessment in natural areas. The aim of this study was to assess physical quality indices, the S index, soil aeration capacity (ACt/Pt), and water storage capacity (FC/Pt) of the soil from a permanent plot in the Caetetus Ecological Reserve (Galia, São Paulo, Brazil) under a seasonal semideciduous forest and compare them with the reference values for soil physical quality found in the literature. Water retention curves were used for that purpose. The S values found were higher than the proposed limit for soil physical quality (0.035). The A and E horizons showed the highest values because their sandy texture leads to a high slope of the water retention curve. The B horizons showed the lowest S values because their natural density leads to a lower slope of the water retention curve. The values found for ACt/Pt and FC/Pt were higher and lower than the idealized limits. The values obtained from these indices under natural vegetation can provide reference values for soils with similar properties that undergo changes due to anthropic activities. All the indices evaluated were effective in differentiating the effects of soil horizons in the natural hydro-physical functioning of the soils under study.
Assessment of pedotransfer functions for estimating soil water retention curves for the amazon region
Knowledge of the soil water retention curve (SWRC) is essential for understanding and modeling hy... more Knowledge of the soil water retention curve (SWRC) is essential for understanding and modeling hydraulic processes in the soil. However, direct determination of the SWRC is time consuming and costly. In addition, it requires a large number of samples, due to the high spatial and temporal variability of soil hydraulic properties. An alternative is the use of models, called pedotransfer functions (PTFs), which estimate the SWRC from easy-to-measure properties. The aim of this paper was to test the accuracy of 16 point or parametric PTFs reported in the literature on different soils from the south and southeast of the State of Pará, Brazil. The PTFs tested were proposed by Pidgeon (1972), Lal (1979), Aina & Periaswamy (1985), Arruda et al. (1987), Dijkerman (1988), Vereecken et al. (1989), Batjes (1996), van den Berg et al. (1997), Tomasella et al. (2000), Hodnett & Tomasella (2002), Oliveira et al. (2002), and Barros (2010). We used a database that includes soil texture (sand, silt, and clay), bulk density, soil organic carbon, soil pH, cation exchange capacity, and the SWRC. Most of the PTFs tested did not show good performance in estimating the SWRC. The parametric PTFs, however, performed better than the point PTFs in assessing the SWRC in the tested region. Among the parametric PTFs, those proposed by Tomasella et al. (2000) achieved the best accuracy in estimating the empirical parameters of the van Genuchten (1980) model, especially when tested in the top soil layer.
Genesis of cohesive soil horizons from north-east Brazil: role of argilluviation and sorting of sand
Cohesive horizons are widespread along the Brazilian coastal tablelands and, despite their import... more Cohesive horizons are widespread along the Brazilian coastal tablelands and, despite their importance to soil management under intensive cultivation, their genesis remains, in many aspects, controversial. Studies diverge and indicate the participation of different mechanisms in the formation of these soil horizons. Although clay illuviation has been considered as one of the processes determining the formation of this soil attribute, recent studies suggest a limited participation of this soil process. The aim of the present study was to evaluate the relative contribution of argilluviation and sorting of sand to the genesis of cohesive horizons in an Ultisol toposequence from a toposequence from north-east Brazil. Soil samples were collected from cohesive and non-cohesive horizons from four soil profiles. We determined bulk soil density (BD), penetration resistance (PR), particle size distribution and the percentage of different sand fractions. The sand fractionation data were treated statistically to obtain different grain size parameters, such as mean grain size, sorting and kurtosis. An additional micromorphological study was performed on cohesive and non-cohesive horizons. The lowest BD and PR were recorded in non-cohesive horizons (1.53 Mg m–3 and 0.74 MPa, respectively), whereas significantly higher values of BD (1.66–1.80 Mg m–3) and PR (2.61–7.71 MPa) were observed in cohesive horizons. Thin sections of cohesive soil horizons showed a significant reduction in void sizes and interconnecting pores compared with non-cohesive soil horizons. The higher values of BD and PR observed in the cohesive horizons are apparently related to this poorly interconnected void network. Textural pedofeatures observable with optical microscopy, which indicate argilluviation, were only found in one cohesive horizon. Sand fractionation showed a predominance of medium and fine sand fractions and indicated the dominance of poorly selected sand in cohesive horizons, probably causing the higher BD and PR values. However, the presence of textural pedofeatures (clay coatings) in one of the cohesive horizons studied may indicate a combined contribution of sand heterogeneity and argilluviation in the genesis of these horizons. Overall, the results of the present study showed that subtle variations in the distribution of basic soil components (i.e. particle size fractions) may determine the formation of cohesive horizons and thus must be taken into account in future studies aiming to predict their spatial distribution and to establish more efficient management strategies.
In the soil science, a direct method that allows the study of soil pore distribution is the bi-di... more In the soil science, a direct method that allows the study of soil pore distribution is the bi-dimensional (2D) digital image analysis. Such technique provides quantitative results of soil pore shape, number and size. The use of specific softwares for the treatment and processing of images allows a fast and efficient method to quantify the soil porous system. However, due to the high cost of commercial softwares, public ones can be an interesting alternative for soil structure analysis. The objective of this work was to evaluate the quality of data provided by the Image J software (public domain) used to characterize the voids of two soils, characterized as Geric Ferralsol and Rhodic Ferralsol, from the southeast region of Brazil. The pore distribution analysis technique from impregnated soil blocks was utilized for this purpose. The 2D image acquisition was carried out by using a CCD camera coupled to a conventional optical microscope. After acquisition and treatment of images, they were processed and analyzed by the software Noesis Visilog 5.4® (chosen as the reference program) and ImageJ. The parameters chosen to characterize the soil voids were: shape, number and pore size distribution. For both soils, the results obtained for the image total porosity (%), the total number of pores and the pore size distribution showed that the Image J is a suitable software to be applied in the characterization of the soil sample voids impregnated with resin.
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Papers by Miguel Cooper