Carbono em agregados do solo sob vegetação nativa, pastagem e sistemas agrícolas no bioma Cerrado

Oliveira

Carducci

et al. 2016

SCA

Morphological characteristics of the soil aggregates are important tools to analyzing and monitoring the structural quality. The present study aimed to characterize morphometrically aggregates of a Inceptisol, originated from pelitic rocks, after 1.5 years of the implementation of a management system that adopts conservation tillage practices in the coffee cultivation. The aggregates were collected at the depths of 0.0-0.05; 0. 05-0.20; 0.20-0.40; 0.40-0.80 m, both at row and interrow position in a coffee field, and also a natural environment of native vegetation that was used as a reference for the study. The analyzes of the aggregates were carried through 2D images obtained by scanning at 300 dpi spatial resolution. Each image contained 60 households and were processed using the software QUANTPORO. The morphometric variables were obtained: area, perimeter, compactness, roughness, appearance and Ferret diameter. For validation, the correlations among morphometric variables determined by image analysis and pattern aggregation indices (GMD, MWD and aggregates retained in the class > 2.00 mm) obtained by wet sieving were studied. After 1.5 years of implantation increased the dimensions of the aggregates on the natural environment have been detected, as well as better structural quality Inceptisol. Key words: Image analysis. Morphometric characteristics of the aggregates. Structural quality. ResumoAs características morfológicas dos agregados são importantes indicadores da qualidade estrutural do solo. O presente trabalho teve por objetivo caracterizar morfometricamente os agregados de um Cambissolo originado de rochas pelíticas (siltito) após 1,5 anos da implantação de um sistema de manejo que adota práticas conservacionistas do solo no cultivo do cafeeiro. Os agregados foram coletados nas profundidades de 0,0-0,05; 0,05-0,20; 0,20-0,40; 0,40-0,80 m, nas posições linha e entrelinha do cafeeiro e também em um ambiente natural Cerrado Nativo tomado como referência para o estudo. As análises dos agregados foram realizadas por meio de imagens 2D obtidas por escaneamento, em 300 dpi de resolução espacial. Cada imagem continha 60 agregados e foram processadas utilizando o software Quantporo. As variáveis morfométricas obtidas foram: área, perímetro, compacidade, rugosidade, aspecto e diâmetro de Ferret. Para validação, foram estudadas as correlações entre as variáveis 1 Parte da Dissertação do primeiro autor. Trabalho financiado pelos órgãos CNPq e FAPEMIG.

Section: It Is Also Observed That Casupporting

confidence: 65%

“…These characteristics favor an increase in carbon stocks by physically protecting organic matter within soil aggregates (BAYER et al, 2004;COSTA JÚNIOR et al, 2012) against microbial activity, besides decreasing the availability of oxygen for oxidation processes of decomposition (BALESDENT et al, 2000).…”

Section: Resultsmentioning

confidence: 99%

Aggregates morphometry of a Inceptisol under conservationist system

Oliveira

Carducci

et al. 2016

SCA

“…Costa Júnior et al (2012) found that smaller aggregates have a greater ability to absorb C. In this study, the correlation between SI for fast wetting and the soil exchangeable Ca content was positive (r = 0.73) and significant (p<0.01). However, despite the fact that the Ca 2+ ion promotes flocculation of the soil clay fraction, it is noteworthy that at high concentrations, Ca +2 can displace Al 3+ from the clay surface (initial condition), which can trigger dispersion in the clay fraction .…”

Section: Resultssupporting

confidence: 51%

“…It should be noted that stable aggregates exhibit tightly bound soil fractions that are rarely broken, mainly due to the presence of organic carbon as cementing agent, and can confer good permeability and water infiltration (Lado et al, 2004;Costa Júnior et al, 2012).…”

Section: Resultsmentioning

confidence: 99%

Aggregate stability by the "high energy moisture characteristic" method in an oxisol under differentiated management

Oliveira

et al. 2014

Rev. Bras. Ciênc. Solo

SUMMARYStudies testing the High Energy Moisture Characteristic (HEMC) technique in tropical soils are still incipient. By this method, the effects of different management systems can be evaluated. This study investigated the aggregation state of an Oxisol under coffee with Brachiaria between crop rows and surfaceapplied gypsum rates using HEMC. Soil in an experimental area in the Upper São Francisco region, Minas Gerais, was studied at depths of 0.05 and 0.20 m in coffee rows. The treatments consisted of 0, 7, and 28 Mg ha -1 of agricultural gypsum rates distributed on the soil surface of the coffee rows, between which Brachiaria was grown and periodically cut, and compared with a treatment without Brachiaria between coffee rows and no gypsum application. To determine the aggregation state using the HEMC method, soil aggregates were placed in a Büchner funnel (500 mL) and wetted using a peristaltic pump with a volumetric syringe. The wetting was applied increasingly at two pre-set speeds: slow (2 mm h -1 ) and fast (100 mm h -1 ). Once saturated, the aggregates were exposed to a gradually increasing tension by the displacement of a water column (varying from 0 to 30 cm) to obtain the moisture retention curve [M = f (Ψ Ψ Ψ Ψ Ψ)], underlying the calculation of the stability parameters: modal suction, volume of drainable pores (VDP), stability index (slow and fast), VDP ratio, and stability ratio. The HEMC method conferred sensitivity in quantifying the aggregate stability parameters, and independent of whether gypsum was used, the soil managed with Brachiaria between the coffee rows,

“…The experiment was set up in 1988/1989 in Londrina, state of Parana, (23º11'39" S and 51º10'40" W), in a Rhodic Eutrudox (EMBRAPA, 2013). Details of the experimental area can be found in Barreto et al (2009).…”

Section: Introductionmentioning

confidence: 99%

Carbon in aggregate size classes in a Rhodic Eutrudox under different cropping systems

Machado

Melo

Figueiredo

et al. 2019

SCA

Soil productive capacity is related to levels of carbon (C) in aggregates of different sizes. The aim of this study was to assess total organic carbon levels in different size classes of water-stable aggregates in a Rhodic Eutrudox under different production systems. The cropping systems assessed were no-tillage (NT); no-tillage scarified every three years (NTS); disk plowing (DP) and heavy disking (HD). All systems were subjected to crop succession (S) (soybean - Glycine max / wheat - Triticum aestivum) and rotation (R) (soybean, maize (Zea mays), wheat) and cover and green manure (Lupinus albus, Raphanus sativus and Avena strigosa). Intact soil samples were collected in trenches at depths of 0–0.10; 0.10-0.20; 0.20–0.30 and 0.30-0.40 m. The highest levels of carbon were found under no-tillage, irrespective of the aggregate size class. In all treatments, the top layer (0.0–0,10 m) under crop succession showed the highest carbon content for all aggregate size classes. However, at depths below 0.10 m, crop rotation exhibited the highest carbon levels (between 12 and 20 g kg-1). After 29 years of trials, cropping systems with the lowest soil disturbance combined with crop rotation were found to contribute to raising the level of carbon in the soil and maintaining stable aggregates.